[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

CN108727518B - Process for the polymerization of ethylene and polyethylene - Google Patents

Process for the polymerization of ethylene and polyethylene Download PDF

Info

Publication number
CN108727518B
CN108727518B CN201710260645.2A CN201710260645A CN108727518B CN 108727518 B CN108727518 B CN 108727518B CN 201710260645 A CN201710260645 A CN 201710260645A CN 108727518 B CN108727518 B CN 108727518B
Authority
CN
China
Prior art keywords
filter cake
mesoporous
composite material
cake
mesoporous material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201710260645.2A
Other languages
Chinese (zh)
Other versions
CN108727518A (en
Inventor
亢宇
张明森
吕新平
周俊岭
徐世媛
张志会
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
Original Assignee
Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sinopec Beijing Research Institute of Chemical Industry, China Petroleum and Chemical Corp filed Critical Sinopec Beijing Research Institute of Chemical Industry
Priority to CN201710260645.2A priority Critical patent/CN108727518B/en
Publication of CN108727518A publication Critical patent/CN108727518A/en
Application granted granted Critical
Publication of CN108727518B publication Critical patent/CN108727518B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00Polymerisation catalysts
    • C08F4/02Carriers therefor
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F110/00Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F110/02Ethene
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00Polymerisation catalysts
    • C08F4/42Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62Refractory metals or compounds thereof
    • C08F4/64Titanium, zirconium, hafnium or compounds thereof
    • C08F4/642Component covered by group C08F4/64 with an organo-aluminium compound
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00Polymerisation catalysts
    • C08F4/42Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62Refractory metals or compounds thereof
    • C08F4/64Titanium, zirconium, hafnium or compounds thereof
    • C08F4/642Component covered by group C08F4/64 with an organo-aluminium compound
    • C08F4/6421Titanium tetrahalides with organo-aluminium compounds

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
  • Silicates, Zeolites, And Molecular Sieves (AREA)

Abstract

The invention relates to the field of polymerization reaction, and discloses an ethylene polymerization method and polyethylene prepared by the method. The method for polymerizing ethylene comprises the step of polymerizing ethylene in the presence of a catalyst under polymerization reaction conditions, wherein the catalyst comprises a spherical mesoporous composite material and a magnesium salt and/or a titanium salt loaded on the spherical mesoporous composite material, and the spherical mesoporous composite material is prepared by a preparation method comprising the following steps of: (1) preparing a first mesoporous material filter cake; (2) preparing a second mesoporous material filter cake; (3) preparing a silica gel filter cake; (4) and respectively or after mixing the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake, carrying out ball milling on the ball-milled products by using a ceramic membrane filter, and then carrying out spray drying. The method uses a supported catalyst with high activity, and can obtain polyethylene products with lower bulk density and melt index.

Description

Process for the polymerization of ethylene and polyethylene
Technical Field
The invention relates to the field of polymerization reaction, in particular to a method for polymerizing ethylene and polyethylene prepared by the method.
Background
Since the synthesis of a regular mesoporous material with highly ordered pore channels by Mobile corporation in 1992, the material has a high specific surface, a regular pore channel structure and a narrow pore channelThe pore size distribution of the mesoporous material enables the application of the mesoporous material in the fields of catalysis, separation, medicine and the like to get great attention. A novel mesoporous material SBA-15 is synthesized by Zhao Dongyuan et al in 1998, which has highly ordered pore diameter (6-30nm) and large pore volume (1.0 cm)3The preparation method of the mesoporous molecular sieve carrier material is disclosed by D.Y.ZHao, J. L, Feng, Q.S.Huo, et al Science 279(1998) 548-550. CN1341553A, and the mesoporous material prepared by the method is used as a heterogeneous reaction catalyst carrier, so that the separation of the catalyst and a product is easily realized.
However, the conventional ordered mesoporous material SBA-15 has a rod-like microscopic morphology, the flowability of the material is poor, and the high specific surface area and the high pore volume of the material cause the material to have strong water and moisture absorption capacity, so that the agglomeration of the ordered mesoporous material is further aggravated, and the storage, transportation, post-processing and application of the ordered mesoporous material are limited.
The development and application of polyethylene catalysts is a major breakthrough in the field of olefin polymerization catalysts after traditional Ziegler-Natta catalysts, which makes the research of polyethylene catalysts enter a rapidly developing stage. The homogeneous phase polyethylene catalyst has high activity, needs large catalyst consumption and high production cost, and the obtained polymer has no granular shape and cannot be used in a polymerization process of a slurry method or a gas phase method which is widely applied. An effective method for overcoming the above problems is to carry out a supporting treatment of the soluble polyethylene catalyst. At present, a great number of researches on the loading of polyethylene catalysts are reported. In order to develop new support/catalyst/cocatalyst systems in depth, it is necessary to develop different supports to drive the further development of the supported catalyst and polyolefin industries.
At present, common catalyst carriers are mesoporous materials and silica gel carriers. Among them, the mesoporous material has not high enough catalytic activity after loading the polyethylene catalyst, and there is a need to develop a catalyst carrier capable of improving activity to promote further development of the carrier catalyst and polyolefin industry.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for polymerizing ethylene and polyethylene, wherein a supported catalyst used in the method has high catalytic activity and can obtain a polyethylene product with lower bulk density and melt index.
At present, silica gel and mesoporous materials are usually removed by using a plate-and-frame filter press, but the catalytic activity of a carrier obtained by using the method after loading a catalyst is low, possibly because the removal of impurities is not thorough. In addition, the plate and frame filter press still has a lot of shortcomings, for example, plate and frame filter press area is great, simultaneously, because the plate and frame filter press is discontinuous operation, inefficiency, the operation room environment is relatively poor, has secondary pollution, and in addition, because use filter cloth, it is relatively poor to get rid of the impurity effect, and waste water can not recycle, wastes the water source very much in the washing process, simultaneously because the exhaust waste water can't be handled, causes environmental pollution and secondary waste again. After intensive research, the inventor of the present invention finds that when the ceramic membrane is used for washing the spherical mesoporous composite material, the obtained spherical mesoporous composite material has high catalytic activity after loading the polyethylene catalyst, and the obtained polyethylene product has low bulk density and low melt index. The present inventors have completed the present invention based on the above findings.
In order to achieve the above object, the present invention provides a method for polymerizing ethylene, comprising: polymerizing ethylene in the presence of a catalyst under polymerization conditions, wherein the catalyst comprises a spherical mesoporous composite material and a magnesium salt and/or a titanium salt loaded on the spherical mesoporous composite material, and the spherical mesoporous composite material is prepared by a preparation method comprising the following steps: (1) carrying out first mixing contact on a template agent, tetramethoxysilane, ethanol, trimethylpentane and an acid agent, and crystallizing and filtering a mixture obtained by the first mixing contact to obtain a first mesoporous material filter cake; (2) carrying out second mixing contact on ethyl orthosilicate, hexadecyl trimethyl ammonium bromide and ammonia, and filtering a mixture obtained by the second mixing contact to obtain a second mesoporous material filter cake; (3) carrying out third mixing contact on water glass and inorganic acid, and filtering a mixture obtained after the third mixing contact to obtain a silica gel filter cake; (4) respectively or after mixing the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake, carrying out ball milling on the ball-milled products, washing the ball-milled products by using a ceramic membrane filter, and then carrying out spray drying to obtain the spherical mesoporous composite material; or washing the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake respectively or after mixing by using a ceramic membrane filter, and then carrying out ball milling and spray drying to obtain the spherical mesoporous composite material.
The invention also provides polyethylene prepared by the method.
The spherical mesoporous composite material prepared by the ceramic membrane filtration method has the following advantages: (1) the separation process is simple, the separation efficiency is high, the number of matched devices is small, the energy consumption is low, and the operation is simple and convenient; (2) the template agent is directly removed by ceramic membrane filtration, and compared with the prior art, the step of removing the template agent by calcination is omitted; (3) the cross-flow filtration is adopted, and the higher membrane surface flow rate is used, so that the accumulation of pollutants on the membrane surface is reduced, and the membrane flux is improved; (4) the ceramic membrane has good chemical stability, acid resistance, alkali resistance, organic solvent resistance and strong regeneration capability, and can be suitable for the preparation process of the carrier; (5) the production of waste liquid is obviously reduced, and the method is green and environment-friendly.
The spherical mesoporous composite material prepared by the method has large aperture and high specific surface area, and is beneficial to loading of catalytic components; in addition, the carrier has a spherical geometric shape, and the shape has obvious advantages in the aspects of reducing powder agglomeration, improving fluidity and the like. The prepared spherical mesoporous composite material has high catalytic activity in the process of catalyzing ethylene polymerization reaction, and can obtain a polyethylene product with low bulk density and melt index, wherein the obtained polyethylene product is spherical and has uniform particle size.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is an X-ray diffraction pattern of a spherical mesoporous composite material C1 in example 1;
FIG. 2 is an SEM scanning electron micrograph of a spherical mesoporous composite material C1 in example 1;
fig. 3 is a pore size distribution diagram of the spherical mesoporous composite material C1 in example 1.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The present invention provides a process for the polymerization of ethylene, the process comprising: polymerizing ethylene in the presence of a catalyst under polymerization conditions, wherein the catalyst comprises a spherical mesoporous composite material and a magnesium salt and/or a titanium salt loaded on the spherical mesoporous composite material, and the spherical mesoporous composite material is prepared by a preparation method comprising the following steps:
(1) carrying out first mixing contact on a template agent, tetramethoxysilane, ethanol, trimethylpentane and an acid agent, and crystallizing and filtering a mixture obtained by the first mixing contact to obtain a first mesoporous material filter cake;
(2) carrying out second mixing contact on ethyl orthosilicate, hexadecyl trimethyl ammonium bromide and ammonia, and filtering a mixture obtained by the second mixing contact to obtain a second mesoporous material filter cake;
(3) carrying out third mixing contact on water glass and inorganic acid, and filtering a mixture obtained after the third mixing contact to obtain a silica gel filter cake;
(4) respectively or after mixing the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake, carrying out ball milling on the ball-milled products, washing the ball-milled products by using a ceramic membrane filter, and then carrying out spray drying to obtain the spherical mesoporous composite material; or,
and (3) washing the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake respectively or after mixing, and then carrying out ball milling and spray drying to obtain the spherical mesoporous composite material.
In the present invention, the template may be any template that is conventional in the art, as long as the pore structure of the obtained spherical mesoporous composite material meets the requirements. For example, the templating agent may be a triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene. Wherein the templating agent is commercially available (e.g., from Aldrich under the trade name P123, formula EO)20PO70EO20And Mn of 5800) or can be prepared by various conventional methods. When the template is polyoxyethylene-polyoxypropylene-polyoxyethylene, the number of moles of the template is calculated from the number average molecular weight of polyoxyethylene-polyoxypropylene-polyoxyethylene.
In the present invention, the acid agent may be various acidic aqueous solutions conventionally used in the art, and preferably, the acid agent is acetic acid and sodium acetate buffer solution having a pH of 1 to 6. The amount of the acid agent is not particularly limited, and may be varied within a wide range, and it is preferable that the pH value in the first mixing contact is 1 to 7.
According to the present invention, the order of the first mixing and contacting is not particularly limited, and the template, tetramethoxysilane, ethanol, trimethylpentane and acid agent may be mixed at the same time, or any two or three of them may be mixed, and the other components may be added and mixed uniformly. According to a preferred embodiment of the present invention, the template agent, ethanol and acid agent are mixed uniformly, then trimethylpentane is added and mixed uniformly, and then tetramethoxysilane is added and mixed uniformly.
In the present invention, the amount of the template, ethanol, trimethylpentane and tetramethoxysilane may vary over a wide range, for example, the molar ratio of template, ethanol, trimethylpentane and tetramethoxysilane may be 1: 100-500: 200-500: 50-200, more preferably 1: 180-400: 250-400: 70-150.
In the present invention, the conditions of the first mixing contact are not particularly limited, and for example, the conditions of the first mixing contact generally include: the temperature can be 10-60 ℃, preferably 10-20 ℃; the time can be 10 to 72 hours, preferably 10 to 30 hours; the pH may be from 1 to 7, preferably from 3 to 6. In order to further facilitate uniform mixing between the substances, according to a preferred embodiment of the invention, the first mixing contact is carried out under stirring conditions.
In the present invention, the conditions for crystallization of the mixture obtained by the first mixing contact include: the temperature can be 30-150 ℃, preferably 40-80 ℃; the time may be 10 to 72 hours, preferably 20 to 30 hours. According to a preferred embodiment, the crystallization is carried out by hydrothermal crystallization.
According to the invention, the content of the individual substances in the second mixed contact can also be selected and adjusted within a wide range, for example, the molar ratio of ethyl orthosilicate, cetyltrimethylammonium bromide and ammonia can be 1: 0.1-1: 0.1 to 5, preferably 1: 0.2-0.5: 1.5-3.5.
In the present invention, the ammonia is preferably added in the form of aqueous ammonia. The aqueous ammonia of the present invention may be present in a concentration of 10 to 25% by weight.
In the present invention, the second mixed contacting process of tetraethyl orthosilicate, cetyltrimethylammonium bromide and ammonia is carried out in the presence of water. Preferably, part of the water is introduced in the form of aqueous ammonia and part of the water is added in the form of deionized water. In the second mixed contact system of tetraethoxysilane, hexadecyl trimethyl ammonium bromide and ammonia, the molar ratio of tetraethoxysilane to water can be 1:100-200, and is preferably 1: 120-180.
In the present invention, the conditions of the second mixing contact are not particularly limited, and may include, for example: the contact temperature is 25-100 ℃, preferably 50-90 ℃; the contact time is 2-8 hours, preferably 3-7 hours, and the pH may be 7.5-11, preferably 8-10. Preferably, the second mixing contact is carried out under agitation to facilitate uniform mixing between the substances.
In the present invention, the conditions of the third mixed contact are not particularly limited and may be appropriately determined according to a conventional process for preparing silica gel. For example, the conditions of the third mixing contact include: the temperature can be 10-60 ℃, preferably 20-40 ℃; the time may be 1 to 5 hours, preferably 1 to 3 hours; the pH value is 2-4. In order to facilitate uniform mixing of the materials, the third mixing contact process is preferably performed under stirring conditions.
In the present invention, the amounts of the water glass and the inorganic acid may vary within a wide range. For example, the weight ratio of the water glass to the inorganic acid may be 3 to 6: 1.
in the present invention, the water glass is an aqueous solution of sodium silicate, and the concentration thereof may be 3 to 20% by weight, preferably 10 to 20% by weight. The inorganic acid may be various inorganic acids conventionally used in the art, and may be, for example, one or more of sulfuric acid, nitric acid, and hydrochloric acid. The inorganic acids can be used in pure form or in the form of their aqueous solutions, preferably in the form of 3 to 20% by weight aqueous solutions. The inorganic acid is preferably used in such an amount that the pH of the contact reaction system of the water glass and the inorganic acid is 2 to 4.
According to the present invention, in the step (4), the amounts of the first mesoporous material cake, the second mesoporous material cake and the silica gel cake may vary within a wide range, for example, the silica gel cake may be used in an amount of 1 to 200 parts by weight, preferably 20 to 180 parts by weight, and more preferably 50 to 150 parts by weight, relative to 100 parts by weight of the total amount of the first mesoporous material cake and the second mesoporous material cake; the weight ratio of the first mesoporous material filter cake to the second mesoporous material filter cake can be 1:0.1-10, and preferably 1: 0.5-2.
In the invention, the ceramic filter is a gas, liquid and solid separation and purification device which integrates filtration, slag discharge, cleaning and regeneration and takes a ceramic membrane element as a core. The ceramic membrane filter may include a ceramic membrane module and a ceramic membrane element, and the ceramic membrane element may be an inorganic ceramic membrane element (inorganic ceramic membrane for short). The inorganic ceramic membrane is a precise ceramic filter material with a porous structure, which is usually formed by sintering alumina, titanium oxide, zirconium oxide and the like at high temperature, a porous supporting layer, a transition layer and a microporous membrane layer are asymmetrically distributed, and the filtering precision covers micro-filtration, ultra-filtration and nano-filtration. Ceramic membrane filtration is a form of "cross-flow filtration" of fluid separation process: the raw material liquid flows at high speed in the membrane tube, the clarified penetrating fluid containing small molecular components penetrates through the membrane outwards along the direction vertical to the clear penetrating fluid under the drive of pressure, and the turbid concentrated solution containing large molecular components is intercepted by the membrane, so that the purposes of separating, concentrating and purifying the fluid are achieved. The ceramic membrane can be obtained commercially, for example, an inorganic ceramic membrane element obtained from york jiugu high-tech co. The ceramic membrane module may be determined according to the particular circumstances of the ceramic membrane element and the sample to be treated.
According to a specific embodiment, the parameters of the inorganic ceramic membrane elements used in the present invention include: the membrane is made of alumina, and has a shape of multi-channel cylindrical, the number of channels is 19, the diameter of the channel is 4mm, the length is 1016mm, the outer diameter (diameter) is 30mm, and the effective membrane area is 0.24m2
In the present invention, the conditions for the washing treatment using the ceramic membrane filter include: the operating pressure can be from 2.5 to 3.9bar, preferably from 3 to 3.5 bar; the membrane pressure on the side of the circulation may be from 3 to 5bar, preferably from 3.5 to 4.5 bar; the pressure of the membrane at the circulating side can be 2-2.8bar, preferably 2.2-2.6 bar; the flow rate of the circulating side membrane surface can be 4-5m/s, and is preferably 4-4.5 m/s; the pressure of the permeation side is 0.3-0.5 bar; the temperature may be 10-60 ℃. Wherein the operating pressure is the average of the cycle side membrane inlet pressure and the cycle side membrane outlet pressure.
In the invention, the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake can be washed by using a ceramic membrane filter respectively, or the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake can be mixed and then washed by using a ceramic membrane, and then ball milling and spray drying are carried out, or the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake can be mixed and then ball milling is carried out, and the ball milling product is washed by using the ceramic membrane filter and then spray drying is carried out.
According to a specific embodiment, in the step (4), the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake are respectively washed by using a ceramic membrane filter, and then are mixed, ball-milled and spray-dried to obtain the spherical mesoporous composite material.
According to a specific embodiment, in the step (4), the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake are respectively washed by using a ceramic membrane filter, then are respectively ball-milled, and are mixed and then are spray-dried to obtain the spherical mesoporous composite material.
According to a specific embodiment, in the step (4), the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake are mixed and then washed by using a ceramic membrane filter, and then ball-milled and spray-dried to obtain the spherical mesoporous composite material.
According to a specific embodiment, in the step (4), the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake are respectively ball-milled, then the ball-milled products are respectively washed by using a ceramic membrane filter, and the washed products are mixed and then spray-dried to obtain the spherical mesoporous composite material.
According to a specific embodiment, in the step (4), the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake are respectively ball-milled, and then the ball-milled products are mixed and then are washed and spray-dried by using a ceramic membrane filter, so as to obtain the spherical mesoporous composite material.
According to a specific embodiment, in the step (4), the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake are mixed and then ball-milled, and then the ball-milled product is subjected to washing treatment and spray drying by using a ceramic membrane filter, so as to obtain the spherical mesoporous composite material.
The washing treatment may be performed using water and/or an alcohol (e.g., ethanol). According to a preferred embodiment of the present invention, when the content of sodium ions in the washing liquid of the ceramic membrane filter is detected to be 0.02 wt% or less and the content of the template agent is detected to be less than 1 wt%, the filtration is stopped to obtain a filter cake.
According to the present invention, in the step (4), the conditions and the specific operation method of the ball milling are not particularly limited and may be conventionally selected in the art. For example, the ball milling may be carried out in a ball mill in which the inner walls of the milling bowl are preferably lined with polytetrafluoroethylene and the grinding balls in the ball mill may have a diameter of 2-3 mm; the number of the grinding balls can be reasonably selected according to the size of the ball milling tank, and 1 grinding ball can be generally used for the ball milling tank with the size of 50-150 ml; the material of the grinding ball can be agate, polytetrafluoroethylene and the like, and agate is preferred. The ball milling conditions may include: the rotation speed of the grinding ball can be 300-500r/min, the temperature in the ball milling tank can be 15-100 ℃, and the ball milling time can be 0.1-100 hours.
According to the present invention, in step (4), the spray drying may be carried out according to a conventional method. May be at least one selected from the group consisting of a pressure spray drying method, a centrifugal spray drying method and a pneumatic spray drying method. According to a preferred embodiment of the present invention, the spray drying is a centrifugal spray drying method. The spray drying may be carried out in an atomizer. The conditions of the spray drying may include: the temperature is 100-300 ℃, and the rotating speed is 10000-15000 r/min; preferably, the spray drying conditions include: the temperature is 150-250 ℃, and the rotating speed is 11000-13000 r/min.
The preparation method of the spherical mesoporous composite material in the prior art usually further comprises a step of removing the template agent after spray drying, for example, removing the template agent by a calcination method. Because the method of the invention adopts the ceramic membrane for washing treatment, the method for preparing the spherical mesoporous material of the invention can not comprise the step of calcining to remove the template agent.
In the invention, the average particle diameter of the spherical mesoporous composite material is 20-60 μm, and the specific surface area is 150-600m2(iii) g, pore volume of 0.5-1.8m L g, pore diameter in trimodal distribution, and trimodal corresponding to the secondA first mode pore size of 5-15nm, a second mode pore size of 20-40nm and a third mode pore size of 45-60 nm.
Preferably, the average particle diameter of the spherical mesoporous composite material is 40-50 μm, and the specific surface area is 220-300m2The pore volume is 1.1-1.7m L/g, the pore diameter is in trimodal distribution, and the trimodal corresponds to the first most probable pore diameter of 6-9nm, the second most probable pore diameter of 25-35nm and the third most probable pore diameter of 45-54nm, respectively.
In the present invention, the specific surface area, pore volume and pore diameter are measured by a nitrogen adsorption method, and the average particle diameter is measured by a laser particle size distribution instrument. The average particle diameter is the average particle diameter.
According to the present invention, the contents of the spherical mesoporous composite material and the magnesium salt and/or titanium salt supported on the spherical mesoporous composite material in the supported catalyst may vary within a wide range. For example, the spherical mesoporous composite may be included in an amount of 50 to 99 wt%, and the sum of the contents of the magnesium salt and the titanium salt, in terms of magnesium element and titanium element, respectively, may be 1 to 50 wt%, based on the total weight of the catalyst. Preferably, the content of the spherical mesoporous composite material is 85-99 wt% based on the total weight of the catalyst, and the sum of the contents of the magnesium salt and the titanium salt in terms of magnesium element and titanium element is 1-15 wt%.
According to a preferred embodiment of the present invention, the magnesium salt and the titanium salt are used in a weight ratio of 1:0.1 to 2, preferably 1: 0.5-2.
In the present invention, the kind of the magnesium salt and the titanium salt is not particularly limited, and may be conventionally selected in the art. For example, the magnesium salt may be one or more of magnesium chloride, magnesium sulfate, magnesium nitrate and magnesium bromide, preferably magnesium chloride; the titanium salt may be titanium tetrachloride and/or titanium trichloride.
In the invention, the content of each element in the catalyst component can be measured by adopting an X-ray fluorescence spectrum analysis method.
In the present invention, the supported catalyst may be prepared according to various methods conventionally used in the art, as long as a magnesium salt and/or a titanium salt is supported on the spherical mesoporous composite material.
According to a preferred embodiment, the method for preparing the supported catalyst comprises: in the presence of inert gas, the spherical mesoporous composite material is contacted with mother liquor containing magnesium salt and/or titanium salt.
In the present invention, the mother liquor containing magnesium salt and/or titanium salt may be an organic solvent containing magnesium salt and/or titanium salt, the organic solvent may be isopropanol and tetrahydrofuran, and the volume ratio of tetrahydrofuran to isopropanol may be 1: 1-3, preferably 1: 1-1.5.
In the preparation process of the catalyst, the magnesium salt and the titanium salt are preferably used in an excess amount with respect to the spherical mesoporous composite material. For example, the magnesium salt, the titanium salt and the spherical mesoporous composite material are used in an amount such that the spherical mesoporous composite material is contained in an amount of 50 to 99 wt% based on the total weight of the catalyst, and the sum of the contents of the magnesium salt and the titanium salt in terms of magnesium element and titanium element, respectively, is 1 to 50 wt%; preferably, the content of the spherical mesoporous composite material is 85-99 wt% based on the total weight of the catalyst, and the sum of the contents of the magnesium salt and the titanium salt in terms of magnesium element and titanium element is 1-15 wt%.
Preferably, the conditions for contacting the spherical mesoporous composite material with the mother liquor containing magnesium salt and/or titanium salt include: the temperature can be 25-100 ℃, preferably 40-75 ℃; the time can be from 0.1 to 5h, preferably from 1 to 4 h.
In the present invention, the preparation method of the supported catalyst may further include: after the spherical mesoporous composite material is contacted with a mother solution containing magnesium salt and/or titanium salt, the carrier loaded with the magnesium salt and/or titanium salt is filtered and dried. The drying conditions are not particularly limited and may be drying means and conditions which are conventional in the art. Preferably, the preparation of the supported catalyst also comprises a washing process after filtration and before drying, and/or a milling process after drying. The washing and milling conditions can be selected by the person skilled in the art according to the practical circumstances and will not be described in detail here.
In the present invention, the inert gas is a gas which does not react with the raw materials and the product, and may be, for example, nitrogen gas or at least one of group zero element gases in the periodic table, preferably nitrogen gas, which is conventional in the art.
According to the present invention, the conditions of the polymerization reaction may be those conventional in the art. For example, the polymerization reaction is carried out in the presence of an inert gas under conditions comprising: the temperature can be 10-100 ℃, the time can be 0.5-5h, and the pressure can be 0.1-2 MPa; preferably, the temperature is 20-95 ℃, the time is 1-4h, and the pressure is 0.5-1.5 MPa; further preferably, the temperature is 70-85 ℃, the time is 1-2h, and the pressure is 1-1.5 MPa.
The pressure referred to herein is gauge pressure.
In the present invention, the polymerization reaction may be carried out in the presence of a solvent, and the solvent used in the polymerization reaction is not particularly limited, and may be, for example, hexane.
According to the present invention, in a preferred aspect, a process for the polymerization of ethylene comprises: under the condition of polymerization reaction, in the presence of catalyst and adjuvant making ethylene undergo the process of polymerization reaction; preferably, the adjuvant is an alkyl aluminium compound.
In the present invention, the alkyl aluminum compound has a structure represented by formula I:
AlRnX5 (3-n)formula I
In the formula I, R may be each C1-C5Alkyl groups of (a); x5May each be one of the halogen groups, preferably-Cl; n is 0, 1, 2 or 3.
Preferably, said C1-C5The alkyl group of (a) may be one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl and neopentyl.
In the present invention, specific examples of the alkyl aluminum compound include, but are not limited to: trimethylaluminum, dimethylaluminum chloride, triethylaluminum, diethylaluminum chloride, tri-n-propylaluminum, di-n-propylaluminum chloride, tri-n-butylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum, di-n-butylaluminum chloride and diisobutylaluminum chloride. Most preferably, the alkyl aluminium compound is triethyl aluminium.
In the present invention, the amount of the alkyl aluminum compound may also be selected conventionally in the art, and in general, the mass ratio of the alkyl aluminum compound to the amount of the catalyst may be 1:0.1 to 10; preferably, the mass ratio of the alkyl aluminum compound to the catalyst is 1: 0.2 to 8; more preferably 1: 0.4-4.
In the invention, the ethylene polymerization method can further comprise the step of performing suction filtration separation on the final reaction mixture after the polymerization reaction is finished, so as to obtain the polyethylene granular powder.
The invention also provides polyethylene prepared by the method.
The present invention will be described in detail below by way of examples.
In the following examples and comparative examples,
polyoxyethylene-polyoxypropylene-polyoxyethylene, available from Aldrich, abbreviated as P123, having the formula EO20PO70EO20The substance having a number average molecular weight Mn of 5800 is registered with the American chemical Abstract under the accession number 9003-11-6.
The ceramic membrane filter used was an inorganic ceramic membrane element of JWCM19 x 30, available from Kyosu Jiuwu high-tech Co., Ltd., and a packing membrane area of 0.5m2The ceramic membrane module of (a); the parameters of the inorganic ceramic membrane element include: the shape is a multi-channel cylinder, the number of channels is 19, the diameter of the channels is 4mm, the length is 1016mm, and the outer diameter (diameter) is 30 mm.
Scanning electron microscopy analysis was performed on a scanning electron microscope of type X L-30 from FEI USA, pore structure parameter analysis was performed on a nitrogen desorption apparatus of type Autosorb-1 from Conotan USA, wherein prior to testing, the sample was degassed at 200 ℃ for 4 hours, X-ray fluorescence analysis was performed on an X-ray fluorescence analyzer of type Axios-Advanced from Netherlands, and the particle size distribution curve was measured with a Malvern laser particle sizer.
The bulk density of the polyolefin powder was determined by the method specified in GB/T1636-2008.
Polymer melt index: measured according to ASTM D1238-99.
Example 1
This example serves to illustrate the process for the polymerization of ethylene according to the invention and the polyethylene obtained
(1) Preparation of spherical mesoporous composite material
Adding 1g (0.00017mol) of template P123 and 1.69g (0.037mol) of ethanol into 28m L of acetic acid and sodium acetate buffer solution with the pH value of 4.4, stirring at 15 ℃ until the template is completely dissolved, adding 6g (0.05mol) of trimethylpentane into the solution, stirring at 15 ℃ for 8 hours, adding 2.13g (0.014mol) of tetramethoxysilane into the solution, stirring at 15 ℃ for 20 hours, transferring the solution into an agate-lined reaction kettle, carrying out oven crystallization at 60 ℃ for 24 hours, and carrying out suction filtration to obtain a first mesoporous material filter cake A11.
Adding hexadecyl trimethyl ammonium bromide and ethyl orthosilicate into an ammonia water solution with the concentration of 25 weight percent at the temperature of 80 ℃, and then adding deionized water, wherein the adding amount of the ethyl orthosilicate is 1g, and the mol ratio of ammonia to water in the ethyl orthosilicate, the hexadecyl trimethyl ammonium bromide and the ammonia water is 1: 0.37: 2.8: 142 and stirred at the temperature of 80 ℃ for 4 hours, and then the solution is filtered by suction to obtain a second mesoporous material filter cake a 12.
Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in the weight ratio of 5: 1, and then the mixture was subjected to a contact reaction at 20 ℃ for 1.5 hours, followed by adjusting the pH to 3 with sulfuric acid having a concentration of 98% by weight, and then the resulting reaction mass was subjected to suction filtration to obtain a silica gel cake B1.
5g of the filter cake A11 prepared above, 5g of the filter cake A12 prepared above and 10g of the filter cake B1 prepared above are mixed, and the mixture is washed by a ceramic membrane filter until the content of sodium ions is 0.02 wt% and the content of a template agent is less than 1 wt%, so that the spherical mesoporous composite material filter cake is obtained. Wherein the operating pressure of the membrane module is 3.3bar, the pressure of the membrane at the circulating side is 4bar, the pressure of the membrane at the circulating side is 2.5bar, the flow rate of the membrane surface at the circulating side is 4m/s, the pressure of the permeation side is 0.3bar, and the temperature is 20 ℃.3 parts by weight of water is consumed for preparing one part by weight of the spherical mesoporous composite filter cake.
And (2) putting the spherical mesoporous composite filter cake into a ball milling tank of 100m L, wherein the ball milling tank is made of agate, the grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, the rotating speed is 400r/min, closing the ball milling tank, carrying out ball milling for 5 hours at the temperature of 60 ℃ in the ball milling tank, and carrying out spray drying on the slurry subjected to ball milling at the temperature of 200 ℃ at the rotating speed of 12000r/min to obtain the spherical mesoporous composite C1.
The spherical mesoporous composite material C1 is characterized by XRD, a scanning electron microscope and a nitrogen adsorption instrument.
Fig. 1 is an X-ray diffraction pattern, wherein a is an XRD pattern of the spherical mesoporous composite material C1, the abscissa is 2 θ, and the ordinate is intensity. As can be seen from a small-angle spectrum peak appearing in an XRD spectrogram, the spherical mesoporous composite material C1 has a 2D hexagonal pore channel structure which is unique to mesoporous materials.
FIG. 2 is an SEM image. As can be seen from the figure, the microscopic morphology of the spherical mesoporous composite material C1 is microspheres with the particle size of 30-60 μm, and the dispersion performance is good.
Fig. 3 is a pore size distribution diagram of the spherical mesoporous composite material C1. As can be seen from the figure, the spherical mesoporous composite material C1 has a porous structure distribution and uniform pore channels.
The pore structure parameters of the spherical mesoporous composite material C1 are shown in table 1 below.
TABLE 1
Figure BDA0001274655240000151
*: the first most probable aperture, the second most probable aperture, and the third most probable aperture are separated by commas: the first most probable aperture, the second most probable aperture and the third most probable aperture are arranged in the order from left to right.
(2) Preparation of Supported catalysts
0.1g of magnesium chloride and 0.1g of titanium tetrachloride were dissolved in 10m L of a composite solvent of tetrahydrofuran and isopropanol (the volume ratio of tetrahydrofuran to isopropanol was 1: 1.2) to form a catalyst mother liquor, 1g of spherical mesoporous composite material C1 was added to the mother liquor at 45 ℃ to be immersed for 1 hour, and then filtered, and washed with n-hexane for 4 times, dried at 75 ℃ and ground to obtain catalyst D1.
As a result of X-ray fluorescence analysis, the catalyst D1 obtained in this example had a magnesium element content of 7.0 wt% and a titanium element content of 1.7 wt%, calculated as elements.
(3) Ethylene polymerization
In a stainless steel high-pressure polymerization kettle of 2L, nitrogen and ethylene are respectively replaced three times, then 200m L hexane is added, the kettle is heated to 80 ℃, 800m L hexane is added, 2m L hexane solution of triethyl aluminum (TEA) with the concentration of 1 mol/L is added along with the addition of the hexane, 0.5g of catalyst component D1 is added, ethylene gas is introduced, the pressure is increased to 1.0MPa and maintained to 1.0MPa, the reaction is carried out for 1 hour at 70 ℃, then, the polyethylene granular powder is obtained by suction filtration and separation, and the Bulk Density (BD) and the melt index MI of the obtained polyethylene granular powder are obtained2.16And the catalyst efficiencies are listed in table 4.
Example 2
This example serves to illustrate the process for the polymerization of ethylene according to the invention and the polyethylene obtained
(1) Preparation of spherical mesoporous composite material
Adding 1g (0.00017mol) of template P123 and 1.4g (0.03mol) of ethanol into 28m L of acetic acid and sodium acetate buffer solution with the pH value of 4.4, stirring at 10 ℃ until the template is completely dissolved, adding 4.56g (0.04mol) of trimethylpentane into the solution, stirring at 10 ℃ for 8 hours, adding 1.83g (0.012mol) of tetramethoxysilane into the solution, stirring at 10 ℃ for 30 hours, transferring the solution into an agate-lined reaction kettle, carrying out oven crystallization at 80 ℃ for 20 hours, and carrying out suction filtration to obtain a first mesoporous material filter cake A21.
Adding hexadecyl trimethyl ammonium bromide and ethyl orthosilicate into an ammonia water solution with the concentration of 25 weight percent at 50 ℃, and adding deionized water, wherein the adding amount of the ethyl orthosilicate is 1g, and the mol ratio of ammonia to water in the ethyl orthosilicate, the hexadecyl trimethyl ammonium bromide and the ammonia water is 1: 0.5: 1.5: 180 and stirring at 50 ℃ for 7 hours, and then filtering the solution by suction to obtain a second mesoporous material filter cake A22.
Mixing water glass with the concentration of 20 weight percent and sulfuric acid solution with the concentration of 12 weight percent in a weight ratio of 3: 1, and then the mixture is contacted and reacted at 20 ℃ for 3 hours, then the pH value is adjusted to 4 by using sulfuric acid with the concentration of 98 weight percent, and then the obtained reaction material is filtered by suction to obtain a filter cake B2 of silica gel.
6.7g of the filter cake A11, 3.3g of the filter cake A12 and 15g of the filter cake B1 prepared in the above were mixed, and the mixture was washed with a ceramic membrane filter until the sodium ion content was 0.02% by weight and the content of the template agent was less than 1% by weight, to obtain a spherical mesoporous composite filter cake. Wherein the operating pressure of the membrane module is 3bar, the pressure of the membrane at the circulating side is 3.5bar, the pressure of the membrane at the circulating side is 2.5bar, the flow rate of the membrane surface at the circulating side is 4.5m/s, the pressure of the permeation side is 0.4bar, and the temperature is 60 ℃.
And (2) putting the spherical mesoporous composite filter cake into a ball milling tank of 100m L, wherein the ball milling tank is made of agate, the grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, the rotating speed is 500r/min, closing the ball milling tank, carrying out ball milling for 20 hours at the temperature of 35 ℃ in the ball milling tank, and carrying out spray drying on the ball-milled slurry at the temperature of 150 ℃ at the rotating speed of 13000r/min to obtain the spherical mesoporous composite C2.
The pore structure parameters of the spherical mesoporous composite material C2 are shown in table 2 below.
TABLE 2
Figure BDA0001274655240000171
*: the first most probable aperture, the second most probable aperture, and the third most probable aperture are separated by commas: the first most probable aperture, the second most probable aperture and the third most probable aperture are arranged in the order from left to right.
(2) Preparation of Supported catalysts
0.1g of magnesium chloride and 0.2g of titanium tetrachloride were dissolved in 10m L of a composite solvent of tetrahydrofuran and isopropanol (the volume ratio of tetrahydrofuran to isopropanol was 1: 1.5) to form a catalyst mother liquor, 1g of spherical mesoporous composite material C2 was added to the mother liquor at 60 ℃ to be immersed for 1 hour, and then filtered, and washed with n-hexane for 4 times, dried at 75 ℃ and ground to obtain catalyst D2.
As a result of X-ray fluorescence analysis, the catalyst D2 obtained in this example had a magnesium element content of 6.3 wt% and a titanium element content of 1.4 wt%, calculated as elements.
(3) Ethylene polymerization
In a stainless steel high-pressure polymerization vessel of 2L, nitrogen and ethylene were each replaced three times, followed by addition of 200m L hexane, raising the temperature of the vessel to 75 ℃, addition of 900m L hexane, addition of a1 mol/L Triethylaluminum (TEA) solution in hexane of 2m L with addition of hexane, addition of 0.1g of catalyst component D2, introduction of ethylene gas, raising the pressure to 1MPa and maintaining the pressure at 1MPa, reaction at 75 ℃ for 1.5 hours, separation by suction filtration to obtain polyethylene pellet powder, Bulk Density (BD) of the polyethylene pellet powder, melt index MI of the polyethylene pellet powder, and the like2.16And the catalyst efficiencies are listed in table 4.
Example 3
This example serves to illustrate the process for the polymerization of ethylene according to the invention and the polyethylene obtained
(1) Preparation of spherical mesoporous composite material
Adding 1g (0.00017mol) of template P123 and 3.13g (0.068mol) of ethanol into 28m L of acetic acid and sodium acetate buffer solution with the pH value of 4.4, stirring at 20 ℃ until the template is completely dissolved, adding 7.75g (0.068mol) of trimethylpentane into the solution, stirring at 20 ℃ for 8h, adding 3.8g (0.025mol) of tetramethoxysilane into the solution, stirring at 20 ℃ for 10h, transferring the solution into an agate-lined reaction kettle, crystallizing in an oven at 40 ℃ for 30h, and filtering to obtain a first mesoporous material filter cake A31.
Adding hexadecyl trimethyl ammonium bromide and ethyl orthosilicate into an ammonia water solution with the concentration of 25 weight percent at 90 ℃, and adding deionized water, wherein the adding amount of the ethyl orthosilicate is 1g, and the mol ratio of ammonia to water in the ethyl orthosilicate, the hexadecyl trimethyl ammonium bromide and the ammonia water is 1: 0.2: 3.5: 120 and stirring for 3 hours at the temperature of 90 ℃, and then filtering the solution by suction to obtain a second mesoporous material filter cake A32.
Mixing water glass with the concentration of 10 weight percent and sulfuric acid solution with the concentration of 12 weight percent in a weight ratio of 4: 1, and then the mixture is contacted and reacted for 1.5h at 30 ℃, then the pH value is adjusted to 2 by using sulfuric acid with the concentration of 98 weight percent, and then the obtained reaction material is filtered by suction to obtain a filter cake B3 of silica gel.
Mixing 7g of the filter cake A31, 14g of the filter cake A32 and 10g of the filter cake B3, and washing the mixture by using a ceramic membrane filter until the content of sodium ions is 0.02 wt% and the content of a template agent is less than 1 wt%, thereby obtaining the spherical mesoporous composite filter cake. Wherein the operating pressure of the membrane module is 3.4bar, the pressure of the membrane at the circulating side is 4.5bar, the pressure of the membrane at the circulating side is 2.3bar, the flow rate of the membrane surface at the circulating side is 4.2m/s, the pressure of the permeate side is 0.5bar, and the temperature is 40 ℃.
And (2) putting the spherical mesoporous composite filter cake into a ball milling tank of 100m L, wherein the ball milling tank is made of agate, the grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, the rotating speed is 500r/min, closing the ball milling tank, carrying out ball milling for 10 hours at the temperature of 50 ℃ in the ball milling tank, and carrying out spray drying on the slurry subjected to ball milling at the temperature of 250 ℃ at the rotating speed of 11000r/min to obtain the spherical mesoporous composite C3.
The pore structure parameters of the spherical mesoporous composite material C3 are shown in table 3 below.
TABLE 3
Figure BDA0001274655240000191
*: the first most probable aperture, the second most probable aperture, and the third most probable aperture are separated by commas: the first most probable aperture, the second most probable aperture and the third most probable aperture are arranged in the order from left to right.
(2) Preparation of Supported catalysts
0.2g of magnesium chloride and 0.1g of titanium tetrachloride were dissolved in 10m L of a composite solvent of tetrahydrofuran and isopropanol (the volume ratio of tetrahydrofuran to isopropanol was 1: 1) to form a catalyst mother liquor, 1g of spherical mesoporous composite material C3 was added to the mother liquor at 40 ℃ to be immersed for 1 hour, then filtered, and washed with n-hexane for 4 times, dried at 75 ℃ and ground to obtain catalyst D3.
As a result of X-ray fluorescence analysis, the catalyst D3 obtained in this example had a magnesium element content of 5.3 wt% and a titanium element content of 1.1 wt%, calculated as elements.
(3) Ethylene polymerization
In a stainless steel high-pressure polymerization kettle of 2L, nitrogen and ethylene are respectively used for replacing three times, then 200m L hexane is added, the kettle is heated to 85 ℃, 700m L hexane is added, 2m L hexane solution of triethyl aluminum (TEA) with the concentration of 1 mol/L is added along with the addition of the hexane, 1g of catalyst component D3 is added, ethylene gas is introduced, the pressure is increased to 1MPa and maintained to 1MPa, the reaction is carried out for 2 hours at 85 ℃, then, suction filtration and separation are carried out to obtain polyethylene granular powder, and the Bulk Density (BD) and the melt index MI of the obtained polyethylene granular powder are obtained2.16And the catalyst efficiencies are listed in table 4.
Comparative example 1
This comparative example serves to illustrate a reference ethylene polymerization process and the polyethylene obtained
(1) Preparation of the support
Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in the weight ratio of 5: 1 at 20 c, followed by adjustment of the pH to 3 with 98% by weight sulfuric acid, and then treatment of the resulting reaction mass with a plate and frame filter press, followed by washing with water to a sodium ion content of 0.02% by weight, to give a silica gel filter cake. Eleven parts by weight of water were consumed to prepare one part by weight of the silica gel filter cake.
And (3) putting 10g of the silica gel filter cake into a 100ml ball milling tank, wherein the ball milling tank is made of polytetrafluoroethylene, grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, and the rotating speed is 400 r/min. And (3) sealing the ball milling tank, carrying out ball milling for 5h at the temperature of 60 ℃ in the ball milling tank, carrying out spray drying on the ball-milled slurry at the temperature of 200 ℃ at the rotating speed of 12000r/min, and calcining the spray-dried product in a muffle furnace at the temperature of 400 ℃ for 10h in a nitrogen atmosphere to remove hydroxyl and residual moisture, thereby obtaining the silica gel carrier DA 1.
(2) Preparation of Supported catalysts
The procedure was followed as in example 1, except that the spherical mesoporous composite material C1 was replaced with the silica gel carrier DA1 to obtain a supported catalyst DD 1.
As a result of X-ray fluorescence analysis, the obtained catalyst DD1 contained 1.1 wt% of magnesium, 1.7 wt% of titanium, and 18.32 wt% of chlorine.
(3) Ethylene polymerization
Polymerization of ethylene was carried out in accordance with the procedure of experimental example 1, except that the same parts by weight of the supported catalyst DD1 was used in place of the catalyst D1 prepared in example 1. Bulk Density (BD) and melt index MI of the obtained polyethylene granular powder2.16The pulverization rates and the catalyst efficiencies are shown in Table 4.
Comparative example 2
This comparative example serves to illustrate a reference ethylene polymerization process and the polyethylene obtained
(1) Preparation of the support
The procedure of example 1 was followed, except that the washing was not carried out using a ceramic membrane filter, but a mixture of the first mesoporous material cake, the second mesoporous material cake, and the silica gel cake was washed using distilled water, and only the mixture was mixed with distilled water and then subjected to suction filtration, and the washing was repeated until the sodium ion content was 0.02% by weight, to obtain a spherical mesoporous composite filter cake. Eleven parts by weight of water consumed by preparing one part by weight of the spherical mesoporous composite filter cake. Followed by ball milling and spray drying according to the method of example 1, to obtain a spherical mesoporous composite material DC 1.
(2) Preparation of Supported catalysts
The procedure was followed as in example 1, except that the spherical mesoporous composite material C1 was replaced with the spherical mesoporous composite material DC1, to obtain a supported catalyst DD 2.
(3) Ethylene polymerization
Polymerization of ethylene was carried out in accordance with the procedure of Experimental example 1, except thatInstead of the catalyst D1 prepared from example 1, the same parts by weight of the supported catalyst DD2 were used. Bulk Density (BD) and melt index MI of the obtained polyethylene granular powder2.16The pulverization rates and the catalyst efficiencies are shown in Table 4.
Comparative example 3
This comparative example serves to illustrate a reference ethylene polymerization process and the polyethylene obtained
The preparation of the support and supported catalyst was carried out according to the method of comparative example 2, except that the following steps were added after spray drying: and calcining the spray-dried product in a muffle furnace at 400 ℃ for 24h in a nitrogen atmosphere, and removing the template agent to obtain the spherical mesoporous composite material DC2 and the supported catalyst DD 3.
Ethylene polymerization
Polymerization of ethylene was carried out in accordance with the procedure of experimental example 1, except that the same parts by weight of the supported catalyst DD3 was used in place of the catalyst D1 prepared in example 1. Bulk Density (BD) and melt index MI of the obtained polyethylene granular powder2.16The pulverization rates and the catalyst efficiencies are shown in Table 4.
TABLE 4
Figure BDA0001274655240000221
From the results of examples 1-3 and comparative examples 1-3, it can be seen that the polyethylene catalyst prepared by using the spherical mesoporous composite material prepared by the method of the present invention as a carrier has high catalytic activity, and can obtain spherical polyethylene products with low bulk density and low melt index. In addition, the carrier of the supported catalyst prepared by the method of the invention has less water consumption and less generated waste water. The catalyst can be directly loaded after spray drying without calcining, thereby simplifying the preparation process.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (26)

1. A process for the polymerization of ethylene, the process comprising: the method is characterized in that the catalyst contains a spherical mesoporous composite material and magnesium salt and/or titanium salt loaded on the spherical mesoporous composite material, and the spherical mesoporous composite material is obtained by a preparation method comprising the following steps:
(1) carrying out first mixing contact on a template agent, tetramethoxysilane, ethanol, trimethylpentane and an acid agent, and crystallizing and filtering a mixture obtained by the first mixing contact to obtain a first mesoporous material filter cake;
(2) carrying out second mixing contact on ethyl orthosilicate, hexadecyl trimethyl ammonium bromide and ammonia, and filtering a mixture obtained by the second mixing contact to obtain a second mesoporous material filter cake;
(3) carrying out third mixing contact on water glass and inorganic acid, and filtering a mixture obtained after the third mixing contact to obtain a silica gel filter cake;
(4) respectively or after mixing the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake, carrying out ball milling on the ball-milled products, washing the ball-milled products by using a ceramic membrane filter, and then carrying out spray drying to obtain the spherical mesoporous composite material; or,
and (3) washing the first mesoporous material filter cake, the second mesoporous material filter cake and the silica gel filter cake respectively or after mixing, and then carrying out ball milling and spray drying to obtain the spherical mesoporous composite material.
2. The method according to claim 1, wherein the washing treatment using the ceramic membrane filter comprises: the operating pressure is 2.5-3.9bar, the pressure of the circulating side inlet membrane is 3-5bar, the pressure of the circulating side outlet membrane is 2-2.8bar, and the flow rate of the circulating side membrane surface is 4-5 m/s; the pressure of the permeation side is 0.3-0.5 bar; the temperature is 10-60 ℃.
3. The method according to claim 1, wherein, in the step (4), the silica gel cake is used in an amount of 1 to 200 parts by weight with respect to 100 parts by weight of a total amount of the first mesoporous material cake and the second mesoporous material cake.
4. The method according to claim 3, wherein, in the step (4), the silica gel cake is used in an amount of 20 to 180 parts by weight with respect to 100 parts by weight of a total amount of the first mesoporous material cake and the second mesoporous material cake.
5. The method according to claim 3, wherein, in the step (4), the silica gel cake is used in an amount of 50 to 150 parts by weight with respect to 100 parts by weight of a total amount of the first mesoporous material cake and the second mesoporous material cake.
6. The method according to claim 1, wherein the first mesoporous material filter cake and the second mesoporous material filter cake are used in a weight ratio of 1: 0.1-10.
7. The method according to claim 6, wherein the first mesoporous material filter cake and the second mesoporous material filter cake are used in a weight ratio of 1: 0.5-2.
8. The method according to claim 1, wherein, in step (1), the templating agent is a triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene; the acid agent is acetic acid and sodium acetate buffer solution with pH value of 1-6.
9. The method of claim 1, wherein the template, ethanol, trimethylpentane, and tetramethoxysilane are present in a molar ratio of 1: 100-500: 200-500: 50-200.
10. The method of claim 9, wherein the molar ratio of the templating agent, ethanol, trimethylpentane, and tetramethoxysilane is 1: 180-400: 250-400: 70-150.
11. The method of claim 1, wherein the conditions of the first mixing contact comprise: the temperature is 10-60 ℃, the time is 10-72 hours, and the pH value is 1-7; the conditions for crystallization of the mixture obtained by the first mixing contact include: the temperature is 30-150 ℃ and the time is 10-72 hours.
12. The process of claim 1, wherein in step (2), the molar ratio of ethyl orthosilicate, cetyltrimethylammonium bromide and ammonia is 1: 0.1-1: 0.1-5.
13. The process of claim 12, wherein in step (2), the molar ratio of ethyl orthosilicate, cetyltrimethylammonium bromide, and ammonia is 1: 0.2-0.5: 1.5-3.5.
14. The method of claim 1, wherein the conditions of the second mixing contact comprise: the temperature is 25-100 ℃ and the time is 2-8 hours.
15. The method according to claim 1, wherein the weight ratio of the water glass to the inorganic acid is 3-6:1, and the inorganic acid is one or more of sulfuric acid, nitric acid and hydrochloric acid.
16. The method of claim 1, wherein the conditions of the third mixed contacting comprise: the temperature is 10-60 deg.C, the time is 1-5 hr, and the pH value is 2-4.
17. The method of claim 1, wherein the ball milling conditions comprise: the rotation speed of the grinding ball is 300-.
18. The method of claim 1, wherein the conditions of the spray drying comprise: the temperature is 100-300 ℃, and the rotating speed is 10000-15000 r/min.
19. The method as claimed in any one of claims 1 to 18, wherein the spherical mesoporous composite material has an average particle diameter of 20 to 60 μm and a specific surface area of 150 to 600m2The pore volume is 0.5-1.8m L/g, the pore diameter is trimodal distribution, and the trimodal corresponds to the first most probable pore diameter of 5-15nm, the second most probable pore diameter of 20-40nm and the third most probable pore diameter of 45-60 nm.
20. The method as claimed in claim 19, wherein the spherical mesoporous composite has an average particle diameter of 40-50 μm and a specific surface area of 220-300m2The pore volume is 1.1-1.7m L/g, the pore diameter is in trimodal distribution, and the trimodal corresponds to the first most probable pore diameter of 6-9nm, the second most probable pore diameter of 25-35nm and the third most probable pore diameter of 45-54nm, respectively.
21. The method according to claim 1, wherein the spherical mesoporous composite material is contained in an amount of 50 to 99 wt%, and the sum of the contents of the magnesium salt and the titanium salt, in terms of magnesium element and titanium element, respectively, is 1 to 50 wt%, based on the total weight of the catalyst.
22. The method of claim 21, wherein the spherical mesoporous composite is present in an amount of 85 to 99 wt%, and the sum of the amounts of the magnesium salt and the titanium salt, calculated as magnesium and titanium, is 1 to 15 wt%, based on the total weight of the catalyst.
23. The method of claim 1, wherein the catalyst is prepared by a method comprising: in the presence of inert gas, the spherical mesoporous composite material is contacted with mother liquor containing magnesium salt and/or titanium salt.
24. The method of claim 23, wherein the conditions of the contacting comprise: the temperature is 25-100 ℃ and the time is 0.1-5 h.
25. The process of claim 1, wherein the polymerization reaction is carried out in the presence of an inert gas, and the conditions of the polymerization reaction include: the temperature is 10-100 ℃, the time is 0.5-5h, and the pressure is 0.1-2 MPa.
26. A polyethylene prepared by the process of any one of claims 1 to 25, wherein the polyethylene has a bulk density of 0.4g/m L and a melt index MI2.160.3g/10min, or the polyethylene has a bulk density of 0.41g/m L and a melt index MI2.16Is 0.39g/10 min;
alternatively, the polyethylene has a bulk density of 0.4g/m L and a melt index MI2.16It was 0.4g/10 min.
CN201710260645.2A 2017-04-20 2017-04-20 Process for the polymerization of ethylene and polyethylene Active CN108727518B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201710260645.2A CN108727518B (en) 2017-04-20 2017-04-20 Process for the polymerization of ethylene and polyethylene

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201710260645.2A CN108727518B (en) 2017-04-20 2017-04-20 Process for the polymerization of ethylene and polyethylene

Publications (2)

Publication Number Publication Date
CN108727518A CN108727518A (en) 2018-11-02
CN108727518B true CN108727518B (en) 2020-07-24

Family

ID=63933368

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201710260645.2A Active CN108727518B (en) 2017-04-20 2017-04-20 Process for the polymerization of ethylene and polyethylene

Country Status (1)

Country Link
CN (1) CN108727518B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108722382B (en) * 2017-04-20 2021-04-13 中国石油化工股份有限公司 Spherical mesoporous composite material, supported catalyst and preparation method thereof

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100953545B1 (en) * 2004-03-23 2010-04-21 삼성에스디아이 주식회사 Supported catalyst and method of preparing the same
CN105330767B (en) * 2014-06-13 2018-03-02 中国石油化工股份有限公司 A kind of support type polyethylene catalyst and preparation method thereof and support type polyethylene catalysts and application
CN106467582B (en) * 2015-08-17 2018-11-30 中国石油化工股份有限公司 The spherical complex carrier of macropore two dimension straight channels and composite material containing polyethylene catalysts with and its preparation method and application
CN106467579B (en) * 2015-08-17 2018-11-30 中国石油化工股份有限公司 Macropore two dimension double hole channel spherical complex carrier and composite material and their preparation method and application containing polyethylene catalysts

Also Published As

Publication number Publication date
CN108727518A (en) 2018-11-02

Similar Documents

Publication Publication Date Title
CN105330768B (en) A kind of support type polyethylene catalyst and preparation method thereof and support type polyethylene catalysts and application
CN105330769B (en) A kind of support type polyethylene catalyst and preparation method thereof and support type polyethylene catalysts and application
CN105440168A (en) Spherical montmorillonite mesoporous composite carrier, loaded polyethylene catalyst, preparation methods of spherical montmorillonite mesoporous composite carrier and loaded polyethylene catalyst and use of loaded polyethylene catalyst
CN106632760B (en) Spherical aluminum-containing mesoporous composite material, supported catalyst, preparation method and application of supported catalyst, and ethylene polymerization method
CN108017740B (en) Spherical porous mesoporous composite material, supported catalyst and preparation method thereof
CN108727518B (en) Process for the polymerization of ethylene and polyethylene
CN108727523B (en) Process for the polymerization of ethylene and polyethylene
CN107840913B (en) Spherical small-particle-size mesoporous composite material, supported catalyst and preparation method of supported catalyst
CN108003261B (en) Method for polymerizing ethylene and polyethylene
CN108794666A (en) The method and polyethylene of vinyl polymerization
CN110734511B (en) Polyolefin catalyst with spherical double-mesoporous composite material as carrier, polyolefin and preparation methods of polyolefin catalyst and polyolefin
CN107417820B (en) Spherical diatomite mesoporous composite material, supported catalyst and preparation method thereof
CN108722382B (en) Spherical mesoporous composite material, supported catalyst and preparation method thereof
CN108727522B (en) Process for the polymerization of ethylene and polyethylene
CN107840912B (en) Method for polymerizing ethylene and polyethylene
CN108786919B (en) Supported metallocene catalyst, preparation method and application thereof, and preparation method of methyl acrylate
CN108727519B (en) Three-dimensional cubic mesoporous composite material, supported catalyst and preparation method thereof
CN108929393B (en) Spherical double-mesoporous attapulgite composite carrier and preparation method and application thereof
CN108727520B (en) Double-hole spherical mesoporous composite material, supported catalyst and preparation method thereof
CN108017731B (en) Spherical mesoporous composite material, supported catalyst and preparation method thereof
CN108623723B (en) Ethylene polymerization process and polyethylene
CN107417824B (en) Method for polymerizing ethylene and polyethylene
CN108623720B (en) Spherical mesoporous composite material, supported catalyst and preparation method thereof
CN107417831B (en) Method for polymerizing ethylene and polyethylene
CN108794667A (en) Silica-gel carrier and loaded catalyst and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant