CN110627928A

CN110627928A - Method for preparing hydrogenated copolymer by hydrogenation of conjugated diene

Info

Publication number: CN110627928A
Application number: CN201910972712.2A
Authority: CN
Inventors: 王耀伟; 王辉; 马韵升; 黎艳艳; 栾波; 任学斌; 刘振学; 曹峰; 郝福兰; 周德芳; 郭宗磊; 佟伟超; 杜庆之; 王勇; 王英超
Original assignee: Shandong Jingbo Zhongju New Materials Co Ltd; Qingdao University of Science and Technology; Shandong Chambroad Petrochemicals Co Ltd
Current assignee: Shandong Jingbo Zhongju New Materials Co Ltd; Qingdao University of Science and Technology; Shandong Chambroad Petrochemicals Co Ltd
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2019-12-31
Anticipated expiration: 2039-10-14
Also published as: CN110627928B

Abstract

The invention provides a method for preparing hydrogenated copolymer by hydrogenation of conjugated diene, which comprises the following steps: a) mixing part of the conjugated diene rubber latex with a Holveda-Grubbs II catalyst to obtain a mixture A; b) mixing the residual conjugated diene rubber latex, the mixture A and an auxiliary agent to obtain a mixture B; the auxiliary agent is potassium oleate and/or sodium oleate; c) introducing hydrogen into the mixture B to perform stirring and degassing treatment, and then continuing stirring treatment to obtain a mixture C; d) and (3) heating the mixture C and increasing the hydrogen pressure to carry out hydrogenation reaction to obtain the hydrogenated copolymer. According to the invention, through a mixing mode that the conjugated diene latex and the Holveda-Grubbs II catalyst are added in batches, a specific auxiliary agent is introduced, and a treatment means that hydrogen is adopted in advance for degassing treatment and stirring is carried out after degassing treatment is carried out, the selective hydrogenation reaction of the conjugated diene can be efficiently realized under the solvent-free condition, and a product with high hydrogenation degree is obtained.

Description

Method for preparing hydrogenated copolymer by hydrogenation of conjugated diene

Technical Field

The invention relates to the technical field of catalytic hydrogenation, in particular to a method for preparing a hydrogenated copolymer by hydrogenation of conjugated diene.

Background

The research and development of the hydrogenated diene-based rubber product mainly obtains the rubber product with required performance through formula design and subsequent processing methods according to the application environment of the rubber part. At present, in both laboratory and industrial production, hydrogenated diene-based rubbers, such as nitrile-butadiene rubber (also referred to as NBR) prepared by polymerization of acrylonitrile and butadiene, are mainly prepared by hydrogenating the parent diene-based unsaturated polymer in 3 ways, taking NBR as an example, three preparation methods are specifically as follows:

(1) acrylonitrile-ethylene copolymerization. In the copolymerization of ethylene and acrylonitrile, since reactivity ratios of acrylonitrile and ethylene are greatly different (0.04 for acrylonitrile and 0.8 for ethylene), the charging ratio of the reaction raw materials must be strictly controlled. In addition, group rearrangement easily occurs in the copolymerization reaction process, side reactions are more, the randomness of chain segments is poor, the performance of the obtained product is poor, and the processing performance of the product is finally influenced, so the method is still in the research stage at present.

(2) Emulsion hydrogenation: adding a heavy metal catalyst into the butyronitrile latex for hydrogenation to prepare HNBR. The United states Goodyear company firstly proposed a process for preparing emulsion HNBR by using diimide as a reducing agent in 1984, NBR latex can directly generate HNBR (related US patent application: US4452950A) under the action of hydrazine hydrate, oxygen or hydrogen peroxide as an oxidizing agent and iron and copper metal ion initiators, but the reduction mode is easy to generate gel, the utilization rate of hydrazine or hydrogen peroxide is low, and the recovery is difficult. The emulsion hydrogenation has the advantages of mild reaction conditions compared with solution hydrogenation, simple process, reduced cost and pollution, and the product can be recycled (the product is emulsion and can be used as special coating). Therefore, NBR emulsion hydrogenation processes are receiving increasing attention. The disadvantage is that the double bonds which are not hydrogenated may have crosslinking reaction, which leads to the increase of the system viscosity and influences the later processing; the emulsion polymerization of NBR leads to difficulties in product separation due to the severe crosslinking reactions which make the product gel-forming easily. Meanwhile, the emulsion hydrogenation method has the problem of slow hydrogenation rate, and is not suitable for large-scale production.

At present, both an ethylene-acrylonitrile copolymerization method and an NBR emulsion polymerization method are in a laboratory research stage, and no prior case exists for industrial application. The only industrialization is NBR solution hydrogenation, which is used by german langerhans, japanese rapes and zanan technologies. Due to the difference of catalytic systems used in hydrogenation reactions, the Japan Rui Wen corporation mainly adopts palladium/white carbon black heterogeneous catalyst with white carbon black as a carrier to prepare HNBR; the Langsheng company mainly adopts rhodium homogeneous catalysisReagent RhCl (P (C)₆H₅)₃)₃Preparing HNBR; the Zanan company mainly adopts ruthenium catalyst to prepare HNBR.

(3) Solution hydrogenation process

The NBR solution hydrogenation method comprises a heterogeneous solution hydrogenation method and a homogeneous solution hydrogenation method, wherein during operation, NBR is crushed and dissolved in a proper organic solvent, and the used solvent mainly comprises cyclohexanone, xylene, chloroform and the like. And placing the HNBR in a high-temperature high-pressure reactor, reacting the HNBR with hydrogen under the action of a noble metal catalyst, and carrying out selective hydrogenation to prepare HNBR.

The solution hydrogenation method is the main method for industrially producing HNBR at present. In the hydrogenation, only the double bonds of the butadiene units are selectively hydrogenated to reduce them to saturated single bonds, without hydrogenating the nitrile groups. The key to the solution hydrogenation process is the choice of catalyst. The NBR solution hydrogenation method can be classified into heterogeneous hydrogenation using a group viii metal coated on an inorganic carrier as a catalyst and homogeneous hydrogenation mainly using a catalyst such as a rhodium-based, ruthenium-based, or palladium-based catalyst. The heterogeneous catalyst adopted by the heterogeneous solution hydrogenation method is a supported catalyst which takes palladium, rhodium, ruthenium and the like as active components and takes alumina, silica, active carbon, carbon black, alkaline earth metal carbonate and the like as carriers, and a hydrogenation product is directly separated from the catalyst by adopting a filtration or centrifugal separation method after the hydrogenation reaction is finished. In the 80 th century of the Japan Ruizui company, the supported catalyst is used for NBR hydrogenation reaction at the earliest, the heterogeneous carrier catalyst is a palladium/carbon catalyst taking carbon as a carrier, the catalyst has high selectivity, the hydrogenation rate can reach as high as 95.6%, but in the hydrogenation reaction, the carbon is easy to adsorb rubber molecules, so that the agglomeration is caused, and the product performance is influenced. The main advantage of the heterogeneous supported catalyst is that the catalyst is easy to separate, but the activity and selectivity of the hydrogenation catalyst are greatly influenced by the environment. In addition, most of active components of the supported catalyst prepared by the traditional method are distributed in the pore channel, NBR molecules must diffuse into the pore channel to carry out hydrogenation reaction, in order to improve the reaction rate, the reaction must be carried out under the conditions of high pressure and strong stirring, the reaction time is long, the energy consumption of the process is high, and the performance of the polymer is easy to deteriorate.

The art of catalytic hydrogenation of polymers based on organic solutions is well established and relevant patents include US-A-6,410,657, US-A-6,020,439, US-A-5,705,571, US-A-5,057,581 and US-A-3,454,644. Carbon-carbon double bonds in diene-based polymers can be selectively hydrogenated by treating the polymer in organic solution with hydrogen in the presence of a catalyst to produce their saturated polymers having significantly improved end-use properties. Such a process may be selective for the double bond to be hydrogenated, so that, for example, the double bond in an aryl or cycloalkyl group is not hydrogenated and the double or triple bond between carbon and other atoms, such as nitrogen or oxygen, is not affected. The art includes many examples of catalysts suitable for such hydrogenation, including cobalt, nickel, rhodium, ruthenium, osmium, and iridium-based catalysts. The suitability of the catalyst depends on the desired degree of hydrogenation, the rate of hydrogenation reaction and the presence or absence of other groups such as carboxyl and nitrile groups in the polymer.

US 6410657 discloses a process for the selective hydrogenation of unsaturated double bonds in conjugated diene units of homopolymers or copolymers in the presence of a homogeneous organotitanium-based catalyst. The use of a catalyst mixture consisting of a substituted or unsubstituted monocyclopentadienyl titanium compound and lithium hydride derived from the reaction of an alkyl lithium with hydrogen in solution exhibits a high degree of hydrogenation and hydrogenation reproducibility.

US 6020439 discloses a process for the hydrogenation of living polymers comprising mainly conjugated double bond monomers and aromatic vinyl monomers. A polymer produced from at least one conjugated diene compound is contacted with hydrogen in the presence of a catalyst. The catalyst is formed from a cyclopentadienyl titanium compound. The promoter is provided in the form of a lithium alkoxide compound. The catalyst system selectively hydrogenates unsaturated double bonds within the conjugated diene units of the living polymer in solution.

US 5705571 discloses a process for the selective hydrogenation of conjugated diene polymers. The process comprises contacting a conjugated diene polymer with hydrogen in an inert organic solvent in the presence of a hydrogenation catalyst composition comprising a substituted or unsubstituted bis (cyclopentadienyl) group VIII transition metal compound and an organolithium compound.

US 5057581 discloses a process for the selective hydrogenation of carbon-carbon double bonds of conjugated diene copolymers in homogeneous solution in an organic solvent in the presence of certain divalent ruthenium carbonyl complex catalysts comprising phosphine ligands with bulky alkyl substituents.

US 3454644 discloses the hydrogenation in solution of unsaturated organic compounds having 2 to 20 carbon atoms containing at least one moiety selected from the group consisting of ketones, formyl, nitriles, non-aromatic carbon double bonds and carbon-carbon triple bonds using as catalyst a ruthenium or osmium metal complex bonded to two electronegative species selected from the group consisting of hydrogen and halogen and coordinated to at least two organic stabilizing ligands such as carbonyl or tertiary phosphines.

In summary, the prior art mainly comprises dissolving the polymer in an organic solvent, and carrying out the hydrogenation of the diene-based polymer in an organic solvent system. However, the dissolution of the polymer in organic solvents has several disadvantages and problems.

However, many diene-based polymers/copolymers are prepared by emulsion polymerization and are in the form of a latex when discharged from the polymerization reactor. It would therefore be highly desirable to develop a process which allows the direct hydrogenation of diene-based polymer latices. Direct hydrogenation of polymer latices has received increasing attention in the last decade. Much effort has been expended to implement this method as described below.

US 6552132 discloses a process for the hydrogenation of polymers consisting of diene monomer units and nitrile group-containing monomer units, wherein the hydrogenation is carried out in the presence of hydrazine and an oxidizing compound in the form of an aqueous dispersion.

US 6521694 discloses a process for hydrogenating the carbon-carbon double bonds of unsaturated polymers in the form of an aqueous dispersion, in which (1) a reducing agent selected from hydrazine and hydrazine-releasing compounds, (2) an oxidizing compound and (3) a catalyst are added to the unsaturated polymer, wherein the catalyst contains an element of group 13 of the periodic table of the elements.

US 5272202 discloses a process for the selective hydrogenation of carbon-carbon double bonds of nitrile group-containing unsaturated polymers with hydrogen in the presence of a hydrogenation catalyst. Relates to an aqueous emulsion of an unsaturated polymer containing nitrile groups. Optionally, an organic solvent capable of dissolving or swelling the polymer is present in a volume ratio of aqueous emulsion to organic solvent in the range of 1: 3 to 1: 0. A palladium compound is used as the hydrogenation catalyst. The aqueous emulsion is contacted with gaseous or dissolved hydrogen while maintaining the emulsified state.

JP02178305 discloses a process for the hydrogenation of nitrile rubbers by contacting the emulsion with hydrogen in the presence of a Pd compound and optionally swelling the emulsion in an organic solvent. Thus, 100ml of a 10% nitrile rubber emulsion (containing 39.4% units derived from acrylonitrile) was mixed with 63.3mg of palladium benzoate in 50ml of benzene and heated at 50 ℃ for 6 hours under a hydrogen pressure of 30atm to give a 90.2% hydrogenated emulsion.

EP 1705194 a1 discloses a process for hydrogenating diene-based polymer latexes using an organometallic catalyst and high pressure gaseous hydrogen. The organometallic catalyst is RhCl (PPh)₃)₃. A 300ml glass lined stainless steel autoclave with temperature control, stirrer and hydrogen addition point was used. A butadiene-acrylonitrile polymer latex having a limited acrylonitrile content of about 38% by weight and a Mooney viscosity (ML1+4@100 ℃ C.) of about 29 was used, the latex having a solids content of 14.3% by weight. The average diameter of the polymer particles in the latex was about 75 nm. And carrying out hydrogenation reaction with a catalyst in a water medium system. After 87 hours, the degree of hydrogenation reached 92%. The main problems of this technique are the slow reaction rate, resulting in very long times and low catalytic efficiency.

In summary, there are two main approaches to the above field of research: one approach is similar to conventional solution catalytic hydrogenation, which hydrogenates the polymer in latex form; another approach involves the use of hydrazines and the like, in which a source of hydrogen is generated in situ as a result of a redox reaction. However, both of the two approaches have problems of poor hydrogenation reaction rate, poor conversion rate and easy gel formation, and the hydrogenation reaction usually needs to be carried out in the presence of an organic solvent, which causes environmental pollution and increased cost due to the use of the organic solvent.

Disclosure of Invention

In view of the above, the present invention is directed to a method for preparing a hydrogenated copolymer by hydrogenating a conjugated diene. The method provided by the invention can efficiently realize the hydrogenation reaction of the conjugated diene under the solvent-free condition, reduce the dosage of the catalyst, accelerate the reaction rate and obtain a product with high hydrogenation degree.

The invention provides a method for preparing hydrogenated copolymer by hydrogenation of conjugated diene, which comprises the following steps:

a) mixing part of the conjugated diene rubber latex with a Holveda-Grubbs II catalyst to obtain a mixture A;

b) mixing the residual conjugated diene rubber latex, the mixture A and an auxiliary agent to obtain a mixture B;

the auxiliary agent is potassium oleate and/or sodium oleate;

c) introducing hydrogen into the mixture B to perform stirring and degassing treatment, and then continuing stirring treatment to obtain a mixture C;

d) and (3) heating the mixture C and increasing the hydrogen pressure to carry out hydrogenation reaction to obtain the hydrogenated copolymer.

Preferably, in the step c), the degassing treatment is performed at a temperature of 0-50 ℃, under a pressure of 0.1-6 MPa, and for a time of 10-300 min.

Preferably, in the step c), the speed of the continuous stirring treatment is 50-800 r/min, and the time is 30-12 h.

Preferably, the conjugated diene rubber latex is butadiene-acrylonitrile polymer latex;

the acrylonitrile content in the latex is 15-50 wt%;

the solid content of the latex is 10-30%;

the Mooney viscosity ML (1+4@100 ℃) of the latex is 55 +/-3.

Preferably, the conjugated diene rubber latex is cis-gloss NBR 3355.

Preferably, the mass ratio of the Hoveda-Grubbs II catalyst to the diene polymer in all the conjugated diene rubber latex is 0.0001-5%;

the mass ratio of the conjugated diene rubber latex in the step a) to the conjugated diene rubber latex in the step b) is (0.1-10) to 1.

Preferably, the mass ratio of the auxiliary agent to all the conjugated diene rubber latex is 0.001-20%.

Preferably, in the step d), the temperature is increased to 35-200 ℃, the hydrogen pressure is increased to 0.5-35 MPa, and the reaction is carried out for 10 min-24 h.

Preferably, in the step c), the degassing treatment is carried out at a temperature of 10-30 ℃, a pressure of 0.5-4 MPa and a time of 20-240 min;

the speed of the continuous stirring treatment is 200-400 r/min, and the time is 2-4 h;

in the step d), the temperature is increased to 60-200 ℃, the hydrogen pressure is increased to 3-10 MPa, and the reaction lasts 15 min-20 h.

Preferably, the mass ratio of the Hoveda-Grubbs II catalyst to the diene polymer in all the conjugated diene rubber latex is 0.0001-2%;

the mass ratio of the conjugated diene rubber latex in the step a) to the conjugated diene rubber latex in the step b) is (0.5-2) to 1;

the mass ratio of the auxiliary agent to all the conjugated diene rubber latex is 0.01-10%;

in the step c), the degassing treatment is carried out at the temperature of 25 ℃, the air pressure of 1-3 MPa and the time of 30-120 min;

in the step d), the temperature is increased to 80-180 ℃, and the reaction is carried out for 30 min-4 h.

The method provided by the invention is an organic solvent-free hydrogenation method, and by adopting a mixing mode of adding conjugated diene latex and a Heveda-Grubbs II catalyst in batches, a specific auxiliary agent is introduced, and a treatment means of carrying out degassing treatment by adopting hydrogen in advance and stirring after degassing treatment is carried out, so that the selective hydrogenation reaction of conjugated diene can be efficiently realized, the catalyst dosage is reduced, a product with high hydrogenation degree is obtained, the reaction rate can be accelerated, the overall catalytic efficiency is improved, the reaction condition temperature is low, the industrial cost is reduced, and the method is beneficial to green chemical industry and realization of rapid industrialization.

The test result shows that the catalyst dosage can be as low as 0.001%, the hydrogenation reaction time is less than 4h, the hydrogenation degree of the obtained product reaches more than 96%, and no gel is generated in the reaction.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is an infrared spectrum of a sample before and after hydrogenation in example 1 of the present invention;

FIG. 2 shows a sample of example 1 of the present invention before and after hydrogenation¹H-NMR spectrum.

Detailed Description

the auxiliary agent is potassium oleate and/or sodium oleate;

According to the invention, a portion of the conjugated diene latex is first mixed with a Holveda-Grubbs II catalyst to obtain a mixture A.

In the invention, the conjugated diene rubber latex is obtained by polymerizing a diene monomer and a comonomer. Preferably, the conjugated diene rubber latex is butadiene-acrylonitrile polymer latex. The content of acrylonitrile in the butadiene-acrylonitrile polymer latex is preferably 15 wt% to 50 wt%. The solid content of the butadiene-acrylonitrile polymer latex is preferably 10-30%; in some embodiments of the invention, the solids content is 23.6 wt%. The Mooney viscosity ML (1+4@100 ℃ C.) of the butadiene-acrylonitrile polymer latex is preferably 55. + -.3. In the present invention, most preferably, the conjugated diene rubber latex is a cis-gloss NBR3355 latex available from ningbo cis-gloss rubber ltd.

In the invention, the Chinese name of the Holovad-Grubbs II catalyst is (1, 3-bis (2,4, 6-trimethylphenyl) -2-imidazolidinylidene) dichloro (o-isopropoxybenzylidene) ruthenium, and the structure of the Holovad-Grubbs II catalyst is shown as a formula (a):

in the present invention, the mixing is not particularly limited, and one raw material may be added to the other raw material, and then the subsequent feeding step is directly continued; or after part of the latex and the catalyst are fully mixed by the aid of a stirring means, the subsequent feeding step is continued. In some embodiments of the present invention, the first mixing mode is adopted. The temperature of the mixing is not particularly limited in the present invention, and the mixing may be carried out at room temperature. After mixing, a mixture a is obtained.

According to the invention, after obtaining the mixture A, the remaining conjugated diene latex, said mixture A and the auxiliary agent are mixed to obtain the mixture B

In the invention, the auxiliary agent is potassium oleate and/or sodium oleate, and potassium oleate is more preferable. The specific emulsifier is introduced into the reaction system of the invention as an auxiliary agent, and can act synergistically with the catalyst to improve the catalytic efficiency under the solvent-free condition.

In the invention, the mass ratio of the auxiliary agent to all the conjugated diene rubber latex is preferably 0.001-20%; more preferably 0.01% to 10%, most preferably 0.5% to 5%. In some embodiments of the invention, the above-mentioned amount ratio is 0.5%, 2% or 10%.

In the present invention, the mixing manner is not particularly limited, and the raw materials are mixed uniformly according to a mixing method known to those skilled in the art. In some embodiments of the invention, the mixing is performed by stirring. The stirring speed is preferably 100-300 r/min, and the time is preferably 5-30 min. The temperature of the mixing is not particularly limited in the present invention, and the mixing may be carried out at room temperature. After mixing, a mixture B was obtained.

In the steps a) to b), the latex material is added in batches, wherein the mass ratio of the Hoveda-Grubbs II catalyst to the diene polymer in all the conjugated diene latexes is preferably 0.0001% to 5%, more preferably 0.0001% to 2%, and most preferably 0.001% to 0.009%. In some embodiments of the invention, the dosage ratio is 0.001% or 0.009%. Wherein the mass ratio of the conjugated diene rubber latex in the step a) to the conjugated diene rubber latex in the step b) is preferably (0.1-10) to 1, more preferably (0.5-2) to 1, and most preferably 1 to 1. Compared with the prior art, the method obviously reduces the dosage of the catalyst.

In the steps a) to b) of the invention, a specific feeding mode is adopted, part of latex is mixed with the catalyst, and then the rest of latex is added for mixing, and the specific mode of adding latex in batches is adopted, so that the catalyst performance and dispersion are better, and the catalytic effect is better.

According to the present invention, after the mixture B is obtained, hydrogen gas is introduced into the mixture B to perform a stirring degassing treatment, and then the stirring treatment is continued to obtain the mixture C.

In the present invention, the pressure of the introduced hydrogen (i.e., the pressure of the degassing treatment) is preferably 0.1 to 6MPa, more preferably 0.5 to 4MPa, further preferably 1 to 3MPa, and most preferably 1.2 to 2.5 MPa; and in some embodiments of the invention is 2 MPa. Introducing hydrogen to perform degassing treatment on the whole latex system, wherein the degassing treatment temperature is preferably 0-50 ℃, more preferably 10-30 ℃, and most preferably 25 ℃. The time for the degassing treatment is preferably 10-300 min, more preferably 20-240 min, further preferably 30-120 min, and most preferably 50-70 min; in some embodiments of the invention, the degassing is 60 min. In some embodiments of the invention, the degassing treatment is carried out at 25 ℃ and at a pressure of 2MPa for a period of 60 min. In the degassing process, the stirring speed is preferably 50-800 r/min, and more preferably 200-400 r/min; in some embodiments of the invention, the stirring speed is 200 rpm.

In the present invention, after the degassing is completed, the material in the reaction system is continuously stirred. In the invention, the speed of the continuous stirring treatment is preferably 50-800 r/min, and more preferably 200-400 r/min; in some embodiments of the invention, the stirring speed is 200 rpm. The time for the continuous stirring treatment is preferably 30 min-12 h, and more preferably 2-4 h; in some embodiments of the invention, the time of stirring is 4 hours. After the above treatment, a mixture C was obtained.

The latex system is degassed by adopting specific hydrogen and is combined with stirring treatment, so that a good dispersing and activating effect is achieved on the catalyst.

According to the present invention, after obtaining the mixture C, the mixture C is subjected to hydrogenation reaction by raising the temperature and the hydrogen pressure to obtain a hydrogenated copolymer.

In the invention, the temperature rise is preferably to 35-200 ℃, more preferably to 60-200 ℃, further preferably to 80-180 ℃, and most preferably to 90-160 ℃; in some embodiments of the invention, the temperature is raised to 90 ℃.

In the invention, the pressure of the lifting hydrogen is preferably raised to 0.5-35 MPa, and more preferably to 3-10 MPa; in some embodiments of the invention, to 5.52MPa or 6.89 MPa.

In the invention, the time of the hydrogenation reaction can be 10 min-4 h, also can be 0.5-4 h, also can be 1-4 h, and also can be 1-3 h; in some embodiments of the invention, 0.5h, 1h, 2h, 3h, or 4 h. After the above hydrogenation reaction, a hydrogenated copolymer is formed. Taking butadiene-acrylonitrile polymer latex as an example, the hydrogenation reaction route is as follows:

in the present invention, after the completion of the hydrogenation reaction, it is preferable to further add an alcohol solution to coagulate the hydrogenated latex to obtain a hydrogenated copolymer. The alcohol solution is not particularly limited in kind, and may be conventional alcohols well known to those skilled in the art, and is preferably one or more of ethanol and methanol; in some embodiments of the invention, ethanol.

In the present invention, the whole preparation process, i.e., steps a) to d), is carried out in the absence of a solvent. According to the invention, under the condition of no solvent, a specific auxiliary agent is introduced by a mixing mode of adding the conjugated diene latex and the Holveda-Grubbs II catalyst in batches, and activation and dispersion are carried out by a processing means of carrying out degassing treatment by adopting hydrogen in advance and stirring after the degassing treatment.

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

In the following examples, the conjugated diene latex used is Ningbo cis latex NBR3355, the parameters of which are characterized as follows: the acrylonitrile content is about 33% by weight, the Mooney viscosity ML (1+4) at 100 ℃ is 55, the solids content is 23.6% by weight, and the average diameter of the polymer particles in the latex is about 88 nm. The hovyda-grubbs II catalyst used was supplied by sigma aldrich. The reactor used was a 300mL polytetrafluoroethylene high pressure reactor (parr instruments) with temperature control, stirrer and hydrogen addition point.

Example 1

S1, 50mL of latex and 0.00212g of Holveda-grubbs II are added to the reactor.

S2, 50mL of latex and 2g of potassium oleate are added, and the mixture is stirred at 200rpm for 30 min.

S3, introducing hydrogen into the system, wherein the degassing temperature is 25 ℃, the pressure is 2MPa, the time is 60min, and the stirring speed is 200rpm during degassing; after degassing was complete, stirring was continued for 4 h.

S4, heating to 90 ℃, raising the hydrogen pressure to 800psi (5.52MPa), and reacting for 1 hour. The hydrogenated NBR latex was coagulated with ethanol to obtain a HNBR copolymer.

The route of the above hydrogenation reaction is as follows:

the results of the infrared test and the nuclear magnetic hydrogen spectrum test on the samples before and after hydrogenation are respectively shown in fig. 1 and fig. 2, wherein fig. 1 is the infrared spectrum of the sample before and after hydrogenation in example 1 of the invention, and fig. 2 is the infrared spectrum of the sample before and after hydrogenation in example 1 of the invention¹H-NMR spectrum. It can be seen that after the hydrogenation reaction, the carbon-carbon double bonds in the latex feed are hydrogenated.

The resulting coagulum was dissolved in MEK for analysis of the degree of hydrogenation, measured using a FT-IR instrument and calculated using standard methods.

The results show that: after 1 hour of reaction, the degree of hydrogenation was 97.6%. The reaction did not produce a gel and the resulting polymer was soluble in methyl ethyl ketone.

Example 2

S1, 50mL of latex and 0.00212g of Holveda-grubbs II are added to the reactor.

S2, adding 50mL of latex and 10g of potassium oleate, and stirring at 200rpm for 30 min.

S4, heating to 90 ℃, raising the hydrogen pressure to 800psi (5.52MPa), and reacting for 30 min. The hydrogenated NBR latex was coagulated with ethanol to obtain a HNBR copolymer.

The results show that: the reaction did not produce a gel and the resulting polymer was soluble in methyl ethyl ketone.

Example 3

S1, 50mL of latex and 0.00212g of Holveda-grubbs II are added to the reactor.

S2, 50mL of latex and 0.5g of potassium oleate are added, and the mixture is stirred at 200rpm for 30 min.

S4, heating to 90 ℃, raising the hydrogen pressure to 800psi (5.52MPa), and reacting for 2 h. The hydrogenated NBR latex was coagulated with ethanol to obtain a HNBR copolymer.

Example 4

S1, 50mL of latex and 0.000236g of Holveda-grubbs II are added to the reactor.

S4, heating to 90 ℃, raising the hydrogen pressure to 800psi (5.52MPa), and reacting for 3 h. The hydrogenated NBR latex was coagulated with ethanol to obtain a HNBR copolymer.

Example 5

S1, 50mL of latex and 0.000236g of Holveda-grubbs II are added to the reactor.

Example 6

S1, 50mL of latex and 0.000236g of Holveda-grubbs II are added to the reactor.

S4, heating to 90 ℃, raising the hydrogen pressure to 800psi (5.52MPa), and reacting for 4 hours. The hydrogenated NBR latex was coagulated with ethanol to obtain a HNBR copolymer.

Comparative example 1

The procedure is as for the preparation of example 6, except that no potassium oleate emulsifier is added.

Comparative example 2

The procedure is as in example 6 except that no potassium oleate emulsifier is added and the hydrogenation reaction time is extended to 7 h.

Comparative example 3

The procedure is as in example 6, except that the latex is added in one portion and degassed by replacing hydrogen with nitrogen, the reaction time being extended to 6 h. The specific process is as follows:

s1, 100mL of latex, 0.000236g of Holveda-grubbs II, 0.5g of potassium oleate are added to the reactor, and the mixture is stirred at 200rpm for 30 min.

S2, introducing nitrogen into the system, wherein the degassing temperature is 25 ℃, the pressure is 2MPa, the time is 60min, and the stirring speed is 200rpm during degassing; after degassing was complete, stirring was continued for 4 h.

S4, heating to 90 ℃, raising the hydrogen pressure to 800psi (5.52MPa), and reacting for 6 h. The hydrogenated NBR latex was coagulated with ethanol to obtain a HNBR copolymer.

Comparative example 4

The procedure is as for example 6, except that the latex NBR3355 is replaced by blue-ened N41 and the reaction time is extended to 6 h; the latex is demulsified in the hydrogenation process.

Example 7

The hydrogenation degree of the products obtained in examples 2 to 6 and comparative examples 1 to 4 was measured by the test method of example 1, and the results are shown in Table 1.

TABLE 1 hydrogenation Effect of examples 1 to 6 and comparative examples 1 to 4

	Amount of catalyst, phr	The amount of auxiliary agent(s)%	Hydrogenation time h	Hydrogenation pressure, psi	Degree of hydrogenation%
						Example 1	0.009	2	1	800	97.6
Example 2	0.009	10	0.5	800	98.1
						Example 3	0.009	0.5	2	800	96.1
Example 4	0.001	2	3	800	97.2
						Example 5	0.001	10	2	800	98.2
Example 6	0.001	0.5	4	800	97.1
						Comparative example 1	0.001	Is free of	4	800	50.1
Comparative example 2	0.001	Is free of	7	800	90.0
						Comparative example 3	0.001	0.5	6	800	80.8
Comparative example 4	0.001	0.5	6	800	20.2

From the test results of the embodiments 1 to 6, it can be seen that the method of the present invention can obtain a polymer with a high hydrogenation degree under a low catalyst usage amount and a short reaction time, and effectively improve the efficiency of the selective hydrogenation of conjugated diene.

Comparing comparative examples 1-2 with example 6, it can be seen that without the addition of an auxiliary: the degree of hydrogenation of comparative example 1 decreased significantly at the same reaction time; the hydrogenation reaction time was prolonged to 7h, and the hydrogenation degree of comparative example 2 also reached only 90.0%, which is still significantly lower than that of example 6. Therefore, the method can effectively improve the catalytic efficiency under the action of the specific auxiliary agent.

Comparing comparative example 3 with example 6, it can be seen that the hydrogenation degree of comparative example 3 is significantly reduced even though the hydrogenation time is prolonged after changing the feeding manner and the degassing manner. It is demonstrated that the catalytic efficiency can only be effectively improved by activating the latex in the specific batch latex feeding mode and the hydrogen degassing mode.

As can be seen by comparing comparative example 4 with example 6, the hydrogenation level of comparative example 4 is significantly reduced after changing the latex feed. The preparation system and conditions of the invention prove that the catalytic efficiency can be effectively improved for specific latex raw materials.

It can be seen from the comparison between the above examples and comparative examples that the present invention utilizes the batch mixing mode of adding conjugated diene latex and Holveda-Grubbs II catalyst in batches, introduces specific auxiliary agents, and uses hydrogen gas to perform degassing treatment in advance and then performs activation and dispersion by stirring after degassing treatment, and through the above synergistic effects in many aspects, the conjugated diene latex realizes efficient selective hydrogenation reaction under the solvent-free condition, reduces the catalyst usage, accelerates the reaction rate, obtains products with high hydrogenation degree, and does not generate gel during the reaction, and improves the overall catalytic efficiency.

Examples 8 to 13

The preparation processes of examples 1 to 6 were carried out, respectively, except that the hydrogen pressure was raised to 1000psi (6.89MPa) in step S4.

The hydrogenation degree of the products obtained in examples 8 to 13 was measured according to the test method of example 1, and the results are shown in Table 2.

TABLE 2 hydrogenation effects of examples 8 to 13

	Amount of catalyst, phr	The amount of auxiliary agent(s)%	Hydrogenation time h	Hydrogenation pressure, psi	Degree of hydrogenation%
						Example 8	0.009	2	1	1000	99.0
Example 9	0.009	10	0.5	1000	99.1
						Example 10	0.009	0.5	2	1000	98.1
Example 11	0.001	2	3	1000	99.1
						Example 12	0.001	10	2	1000	99.2
Example 13	0.001	0.5	4	1000	98.6

As can be seen from the comparison between table 2 and table 1, the hydrogenation effect can be further improved by increasing the hydrogen pressure.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a hydrogenated copolymer by hydrogenating conjugated diene, which is characterized by comprising the following steps:

the auxiliary agent is potassium oleate and/or sodium oleate;

2. The method according to claim 1, wherein in the step c), the degassing treatment is performed at a temperature of 0 to 50 ℃, a pressure of 0.1 to 6MPa, and a time of 10 to 300 min.

3. The method as claimed in claim 1, wherein in the step c), the speed of the continuous stirring treatment is 50-800 r/min, and the time is 30 min-12 h.

4. The process according to claim 1, wherein the conjugated diene latex is a butadiene-acrylonitrile polymer latex;

the acrylonitrile content in the latex is 15-50 wt%;

the solid content of the latex is 10-30%;

the Mooney viscosity ML (1+4@100 ℃) of the latex is 55 +/-3.

5. The process according to claim 1 or 4, characterized in that the conjugated diene latex is cis-gloss NBR 3355.

6. The process of claim 1, wherein the mass ratio of the hoveya-grubbs ii catalyst to the diene polymer in all conjugated diene latexes is between 0.0001% and 5%;

7. The method according to claim 1, wherein the mass ratio of the auxiliary agent to the total conjugated diene rubber latex is 0.001 to 20%.

8. The method according to claim 1, wherein in the step d), the temperature is raised to 35-200 ℃, the hydrogen pressure is raised to 0.5-35 MPa, and the reaction is carried out for 10 min-24 h.

9. The method according to claim 1, wherein in the step c), the degassing treatment is performed at a temperature of 10 to 30 ℃, a pressure of 0.5 to 4MPa, and a time of 20 to 240 min;

10. The process of claim 1, wherein the mass ratio of the hoveya-grubbs ii catalyst to the diene polymer in all conjugated diene latexes is between 0.0001% and 2%;