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EP2054370A1 - Procede integre et dispositif pour la fabrication d'esters d'acide methacrylique a partir d'acetone et d'acide cyanhydrique - Google Patents

Procede integre et dispositif pour la fabrication d'esters d'acide methacrylique a partir d'acetone et d'acide cyanhydrique

Info

Publication number
EP2054370A1
EP2054370A1 EP07803110A EP07803110A EP2054370A1 EP 2054370 A1 EP2054370 A1 EP 2054370A1 EP 07803110 A EP07803110 A EP 07803110A EP 07803110 A EP07803110 A EP 07803110A EP 2054370 A1 EP2054370 A1 EP 2054370A1
Authority
EP
European Patent Office
Prior art keywords
methacrylic acid
water
esterification
cleaning
heat exchanger
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.)
Withdrawn
Application number
EP07803110A
Other languages
German (de)
English (en)
Inventor
Udo Gropp
Robert Weber
Thomas Schäfer
Andreas Perl
Rudolf Sing
Thomas Mertz
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.)
Roehm GmbH Darmstadt
Original Assignee
Evonik Roehm GmbH
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 Evonik Roehm GmbH filed Critical Evonik Roehm GmbH
Publication of EP2054370A1 publication Critical patent/EP2054370A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C231/00—Preparation of carboxylic acid amides
    • C07C231/14—Preparation of carboxylic acid amides by formation of carboxamide groups together with reactions not involving the carboxamide groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/18—Preparation of carboxylic acid esters by conversion of a group containing nitrogen into an ester group
    • C07C67/20—Preparation of carboxylic acid esters by conversion of a group containing nitrogen into an ester group from amides or lactams
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
    • C07B61/00—Other general methods
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C253/00—Preparation of carboxylic acid nitriles
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/52—Esters of acyclic unsaturated carboxylic acids having the esterified carboxyl group bound to an acyclic carbon atom
    • C07C69/533—Monocarboxylic acid esters having only one carbon-to-carbon double bond
    • C07C69/54—Acrylic acid esters; Methacrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D4/00—Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • the subject matter of the present invention relates generally to a process for the preparation of alkyl esters of methacrylic acid and its secondary products which can be used in a variety of chemical synthesis processes which can lead to a wide variety of further processing products, and to an apparatus for carrying out this process.
  • an object of the invention to provide a process which permits the largest possible utilization of the material streams occurring in the context of the process.
  • an object of the invention was to provide a device for To provide that allows implementation of the method according to the invention.
  • the acetone cyanohydrin can be freed in a rectification column, for example at least from impurities having a boiling point of more than about -5 0 C and less than about 100 0 C, these impurities are attributed to the reaction for the preparation of acetone cyanohydrin can.
  • impurities having a boiling point of more than about -5 0 C and less than about 100 0 C, these impurities are attributed to the reaction for the preparation of acetone cyanohydrin can.
  • methacrylamide resulting gaseous products can be introduced into the reaction mixture of the esterification.
  • the methacrylic acid alkyl ester formed in the esterification of methacrylamide with at least one alkyl alcohol is Washed water and the wash water obtained after washing is returned to the esterification process.
  • the mixture of water and sulfuric acid and optionally further substances from the esterification can be freed, for example, first by means of flotation of solids and optionally additionally subsequently cooled.
  • the cooling can be carried out in heat exchangers and the mixture of water and sulfuric acid and optionally other substances from the esterification in the heat exchanger can be mixed with the washing water obtained in the washing of Methacrylklarealkylesters with water.
  • the entry of the wash water in the heat exchanger takes place such that the inner surfaces of the heat exchanger are at least partially wetted with the wash water during operation.
  • the entry of the wash water into the heat exchanger can be carried out according to the invention, for example, such that during operation are not permanently wetted with the mixture of water and sulfuric acid and optionally other substances from the esterification in contact inner surfaces of the heat exchanger with the wash water.
  • Main cleaning be subjected.
  • substances can be separated, which have a lower boiling point than the methacrylic acid alkyl ester.
  • substances can be separated, which have a higher boiling point than the methacrylic acid alkyl ester. It may, for example, have advantageous effects if substances are separated in the pre-purification, which have a lower boiling point than the alkyl methacrylate and these substances are then condensed by cooling, leaving non-condensed residues in the gas phase and in the
  • the process is carried out such that the aqueous phase is at least partially recycled to the esterification or the organic phase is returned to the pre-purification or both.
  • a process according to the invention is carried out in the context of an integrated plant with a device for splitting sulfuric acid, it may be advantageous if the mixture of water and sulfuric acid is optionally introduced together with other substances into such a plant for splitting the sulfuric acid (sulfuric acid splitting plant) ,
  • SO3 obtained from the sulfuric acid splitting plant can be further processed into sulfuric acid, and the sulfuric acid thus obtained can be used in the production of acetone cyanohydrin.
  • the present invention also relates to an apparatus for the production of alkyl methacrylates, comprising fluid-conducting interconnected
  • Methacrylic acid alkyl ester optionally followed by;
  • the apparatus comprises a rectification column for removing constituents having a boiling point of more than -5 0 C and less than 100 0 C from the produced acetone cyanohydrin and the rectification column is fluidly connected to the plant element for producing acetone cyanohydrin so that the removed components in the reaction for the production of acetone cyanohydrin are recycled.
  • the plant element for producing alkyl methacrylate may be connected in a fluid-conducting manner to the plant element for producing methacrylamide in such a way that gaseous products obtained in the production of methacrylamide are introduced into the reaction mixture of the esterification.
  • the plant element for the production of methacrylic acid ester by esterification of methacrylamide with at least one alkyl alcohol may, for example, at least one scrubber for washing
  • the scrubber may be in fluid communication with the plant element for producing methacrylic acid ester in such a way that the scrubbing water obtained after the scrubbing is recycled to the esterification process.
  • a device according to the invention comprises a plant element in which the mixture of water and sulfuric acid and optionally other substances from the esterification first by means of flotation of
  • Solids can be released and then cooled.
  • a device according to the invention may comprise heat exchangers in fluid communication with the plant element for producing methacrylic acid ester such that the mixture of water and sulfuric acid and optionally further substances from the esterification in the heat exchanger with the in the washing of the plant element for producing methacrylic acid ester such that the mixture of water and sulfuric acid and optionally further substances from the esterification in the heat exchanger with the in the washing of the plant element for producing methacrylic acid ester such that the mixture of water and sulfuric acid and optionally further substances from the esterification in the heat exchanger with the in the washing of the
  • Methacrylic acid alkyl ester is mixed with water obtained washing water.
  • the wash water in the heat exchanger may be provided as a supply line, which allow entry of the wash water such that the inner surfaces of the heat exchanger are at least partially wetted with the wash water during operation.
  • the entry of the wash water can for example be such that during operation are not permanently wetted with the mixture of water and sulfuric acid and optionally other substances from the esterification in contact inner surfaces of the heat exchanger with the wash water.
  • the plant element for purifying the methacrylic acid alkyl ester may further comprise at least one pre-cleaning element and a Main cleaning element, so that the methacrylic acid alkyl ester is subjected to a pre-cleaning and a main cleaning.
  • the precleaning element can, for example, comprise at least one column for condensing methacrylic acid alkyl ester and a device for
  • the at least one apparatus for condensing gaseous substances as part of the pre-cleaning element may moreover be in fluid-conducting connection with a device for phase separation, so that a condensate obtained during the joint after-condensation is subjected to phase separation, whereby an aqueous phase and an organic phase can form.
  • the device for phase separation can furthermore be in fluid-conducting connection with the system element for preparing alkyl methacrylate, for example, such that an aqueous phase obtained in the device for phase separation can be at least partially supplied to the preparation of alkyl methacrylate.
  • the device for phase separation may, for example, be in fluid-conducting connection with the prepurification element in such a way that the organic phase can be returned to the column of the prepurification element, in particular into the top of the column.
  • the present invention furthermore relates to the use of a methacrylic acid alkyl ester obtainable by a process according to any one of claims 1 to 16 for the production of fibers, films, paints, molding compositions, moldings, paper auxiliaries, leather auxiliaries, Flocculants and drilling additives; and fibers, films, lacquers, molding compounds, shaped articles, paper auxiliaries, leather auxiliaries, flocculants or drilling additives based on a methacrylic acid alkyl ester obtainable by a process according to the invention.
  • acetone cyanohydrin is prepared by generally known methods (see, for example, Ullmanns Enzyklopadie der ischen Chemie, 4th Edition, Volume 7). Frequently acetone and hydrocyanic acid are used as reactants.
  • the reaction is an exothermic reaction.
  • the heat of reaction is usually removed by a suitable apparatus.
  • the reaction can in principle be carried out as a batch process or as a continuous process, if a continuous procedure is preferred, the reaction is often carried out in a loop reactor, which is set up accordingly.
  • a key feature of a high yielding product to the desired product is often that the reaction product is cooled with sufficient reaction time and the reaction equilibrium is shifted in the direction of the reaction product.
  • the reaction product for the benefit of overall yield often with a added stabilizer to prevent decomposition in the subsequent workup in the starting materials.
  • the mixing of the reactants acetone and hydrocyanic acid can basically be carried out in substantially any desired manner.
  • the type of mixing depends in particular on whether a discrete mode of operation, for example in a batch reactor, or a continuous mode of operation, for example in the loop reactor, is selected.
  • the acetone is fed into the reaction via a feed tank which has a wash tower. Vent lines that carry acetone and hydrocyanic acid containing exhaust air, can be performed for example through this reservoir.
  • the exhaust air escaping from the storage tank can be washed with acetone, whereby hydrogen cyanide are removed from the exhaust air and recycled into the process.
  • Each of the two or more storage containers can carry a corresponding wash tower. However, it is sufficient in many cases, if only one of the storage tanks is equipped with a corresponding wash tower. In this case, however, it is often useful if corresponding exhaust air lines that can transport acetone and hydrogen cyanide are passed through this container or via this wash tower.
  • the temperature of the acetone in the storage container can basically be within a substantially arbitrary range, insofar as the Acetone is in the liquid state at the corresponding temperature.
  • the temperature in the storage tank is about 0 to about 20 ° C.
  • the acetone used for washing is cooled to a temperature of about 0 to about 10 ° C via a corresponding cooler, for example via a plate cooler with brine.
  • the temperature of the acetone entering the scrubbing tower is therefore preferably, for example, about 2 to about 6 ° C.
  • the hydrocyanic acid required in the reaction can be introduced into the reactor either in liquid or gaseous form. This may be, for example, raw gas from the BMA or from the Andrussow process.
  • the hydrogen cyanide for example, be liquefied, for example by the use of a corresponding cooling brine.
  • hydrocyanic acid coking gas can be used.
  • hydrogen cyanide-containing coke oven gas after washing with potash is continuously washed countercurrently with acetone containing 10% water, and the reaction to acetone cyanohydrin can be carried out in the presence of a basic catalyst in two series gas scrubbing columns.
  • a gas mixture comprising hydrogen cyanide and inert gases in particular a crude gas from the BMA process or from the Andrussow process, can be reacted with acetone in the presence of a basic catalyst and acetone cyanohydrin in a gas-liquid reactor.
  • a raw BMA gas or an Andrussow raw gas is preferably used. That from the above-mentioned usual processes for the production of hydrogen cyanide resulting gas mixture can be used as such or after an acid wash.
  • the raw gas from the BMA process in which hydrogen cyanide and hydrogen are formed essentially from methane and ammonia, typically contains 22.9% by volume of HCN, 71.8% by volume of H 2 , 2.5% by volume. NH3, 1, VoI .-% N 2 , 1, 7 VoI .-% CH 4 .
  • hydrocyanic acid and water are formed from methane and ammonia and atmospheric oxygen.
  • the raw gas of the Andrussow process typically contains about 8% by volume of HCN, 22% by volume of H 2 , 46.5% by volume of N 2 , 15% by volume of H 2 O, 5 when oxygen is used as the source of oxygen Vol .-% CO, 2.5% by volume of NH3 and 0.5% by volume of CH4 and CO 2 .
  • the ammonia contained in the raw gas When using a non-acidic raw gas from the BMA or Andrussow process, the ammonia contained in the raw gas often acts as a catalyst for the reaction. Since the ammonia contained in the raw gas often exceeds the amount required as a catalyst and therefore can lead to high losses of sulfuric acid used for stabilization, such a raw gas is often subjected to an acid wash to eliminate ammonia therefrom. When using such an acid-washed crude gas, however, then a suitable basic catalyst must be added to the reactor in a catalytic amount. In principle, known inorganic or organic basic compounds can act as a catalyst.
  • Hydrogen cyanide in gaseous or in liquid form or a hydrogen cyanide-containing gas mixture and acetone are continuously fed to a loop reactor as part of the continuous procedure.
  • the loop reactor thereby comprises at least one possibility for supplying acetone or two or more such possibilities, at least one possibility for supplying liquid or gaseous hydrocyanic acid, or two or more such possibilities as well as at least one possibility for supplying a catalyst.
  • any alkaline compounds such as ammonia, sodium hydroxide or potassium hydroxide, which can catalyze the conversion of acetone and hydrogen cyanide to acetone cyanohydrin, are suitable as catalyst.
  • Catalyst an organic catalyst in particular an amine is used.
  • Suitable examples are secondary or tertiary amines, such as diethylamine, dipropylamine, thethylamine, tri-n-propylamine and the like.
  • a loop reactor which can be used within the scope of the described process element furthermore has at least one pump, or two or more pumps, and at least one mixing device, or two or more such mixing devices.
  • both mixing devices with movable elements and so-called static mixers are suitable in which immobile flow resistances are provided.
  • static mixers for example, those are suitable which allow a Radio Understand scholar of at least about 10, for example at least about 15 or at least about 20 bar under operating conditions without significant restrictions on the functionality.
  • Corresponding mixers may be made of plastic or metal.
  • plastic are, for example, PVC, PP; HDPE, PVDF, PFA or PTFE.
  • Metal mixers may for example consist of nickel alloys, zirconium, titanium and the like. Also suitable, for example, rectangular mixer.
  • the addition of the catalyst is preferably carried out in the loop reactor downstream of the pump and upstream of a loop reactor Mixing element.
  • Catalysts are used in the context of the reaction described, for example, in such an amount that the overall reaction at a pH of at most 8, in particular at most about 7.5 or about 7 is driven. It may be preferred if the pH in the reaction is within a range of about 6.5 to about 7.5, for example about 6.8 to about 7.2.
  • Feed acetone into the loop reactor it may be advantageous to provide for appropriate mixing of acetone and catalyst prior to feeding into the loop reactor.
  • a corresponding mixing can be done for example by using a mixer with moving parts or by using a static mixer.
  • a continuous procedure in a loop reactor is selected as the operating mode, it may be expedient to investigate the state of the reaction mixture by means of punctual or continuous analyzes. This offers the advantage that, if necessary, it is also possible to react quickly to changes in the state of the reaction mixture. In addition, for example, the reactants can be dosed as accurately as possible in order to minimize yield losses.
  • a corresponding analysis can be carried out for example by sampling in the reactor loop.
  • Suitable analysis methods are, for example, pH measurement, measurement of the heat of reaction or measurement of the composition of the reaction mixture by suitable spectroscopic methods.
  • pH measurement for example, pH measurement, measurement of the heat of reaction or measurement of the composition of the reaction mixture by suitable spectroscopic methods.
  • it has often proven useful to determine the conversion in the reaction mixture on the heat dissipated from the reaction mixture and to compare with the theoretically released heat.
  • the actual reaction can, with a suitable choice of the loop reactor, basically take place in the pipe systems arranged inside the loop reactor. However, since the reaction is exothermic, care can be taken to avoid loss of yield, sufficient cooling or sufficient removal of the heat of reaction. It has often proved to be advantageous if the reaction takes place within a heat exchanger, preferably within a shell-and-tube heat exchanger. Depending on the amount of product to be produced, the capacity of a corresponding heat exchanger can be chosen differently. Heat exchangers with a volume of about 10 to about 40 m 3 have proven particularly suitable for industrial processes.
  • the tube bundle heat exchangers preferably used are heat exchangers which have a liquid-flowed tube bundle in a jacket through which liquid flows.
  • the heat transfer between the two liquids can be adjusted accordingly. It is fundamentally possible in the context of the method described to carry out the reaction to the effect that the reaction mixture is driven through the heat exchanger in the tube bundle itself and the reaction takes place within the tube bundle, wherein the heat is removed from the tube bundle into the sheath liquid.
  • the ratio of jacket volume to volume of the tube bundle may be about 10: 1 to about 1: 10, preferably the volume of the jacket is greater than the volume of the tube bundle (based on the contents of the tubes).
  • the heat removal from the reactor is adjusted with a suitable coolant, for example with water, such that the reaction temperature within a corridor is about 25 to about 45 ° C., in particular about 30 to about 38, in particular about 33 to about 35 ° C. ,
  • a product is continuously removed.
  • the product has a temperature within the above reaction temperatures, for example, a temperature of about 35 0 C.
  • the product is cooled via one or more heat exchangers, in particular via one or more plate heat exchangers.
  • a brine cooling system is used.
  • the temperature of the product after cooling should be about 0 to 10, in particular 1 to about 5 0 C.
  • the product is preferably transferred to a storage container having a buffer function.
  • the product can be further cooled in the storage container, for example, by constantly discharging a partial flow from the storage container to a suitable heat exchanger, for example to a plate heat exchanger, or maintained at a suitable storage temperature. It is quite possible that a post-reaction can take place in the storage container.
  • the return of the product in the storage container can basically be done in any way. It has, however, in some cases as advantageously found that the product is recycled through a system of one or more nozzles in the storage container so that takes place within the storage container, a corresponding mixing of the stored product.
  • From the storage container product is further continuously discharged into a stabilization tank.
  • the product is treated with a suitable acid, for example with H 2 SO 4 .
  • the catalyst is deactivated and the reaction mixture is adjusted to a pH of about 1 to about 3, in particular about 2.
  • Sulfuric acid for example sulfuric acid with a content of about 90 to about 105%, in particular from about 93 to about 98%, of H 2 SO 4 is particularly suitable as the acid.
  • the stabilized product is removed from the stabilization tank and transferred to the purification stage.
  • a portion of the removed, stabilized product can be returned, for example, in such a way in the stabilization tank, that a sufficient mixing of the container is ensured by a system of one or more nozzles.
  • Acetone cyanohydrin which were obtained in an upstream stage, for example, from the reaction of acetone with hydrogen cyanide, subjected to a distillative workup.
  • the stabilized crude acetone cyanohydrin is freed via a corresponding column of low-boiling constituents.
  • a suitable distillation process can be carried out, for example, via only one column.
  • a combination of two or more Use distillation columns also combined with a falling film evaporator.
  • two or more falling film evaporators or two or more distillation columns can be combined.
  • the crude acetone cyanohydrin is usually at a temperature of about 0 to about 15 0 C, for example a temperature of about 5 to about 10 0 C from the storage for distillation.
  • the crude acetone cyanohydrin can be introduced directly into the column.
  • the distillative purification of acetone cyanohydrin is carried out via a distillation column or a rectification column with more than 10 trays or via a cascade of two or more appropriately suitable distillation columns.
  • the heating of the column bottom is preferably carried out with steam. It has been found to be advantageous if the bottom temperature does not exceed a temperature of 140 0 C, good yields and a good cleaning can be achieved if the bottom temperature is not greater than about 130 0 C or not higher than about 110 0 C.
  • the temperature data refer to the wall temperature of the column bottom.
  • the crude acetone cyanohydrin is fed to the column body in the upper third of the column.
  • the distillation is preferably carried out at reduced pressure, for example at a pressure of about 50 to about 900 mbar, in particular about 50 to about 250 mbar and with good results between 50 to about 150 mbar.
  • Gaseous impurities, in particular acetone and hydrocyanic acid are taken off from the top of the column and the separated gaseous substances are cooled by means of a heat exchanger or a cascade of two or more heat exchangers. In this case, preferably a brine cooling with a temperature of about 0 to about 10 0 C is used.
  • the gaseous ingredients of the vapors are given the opportunity to condense.
  • the first condensation stage can take place, for example, at normal pressure. However, it is also possible and has proved to be advantageous in some cases when this first condensation stage under reduced pressure, preferably in the
  • the condensate is forwarded to a cooled collecting vessel and there collected at a temperature of about 0 to about 15 0 C, in particular at about 5 to about 10 0 C.
  • the non-condensing in the first condensation step gaseous compounds are removed via a vacuum pump from the vacuum chamber.
  • a vacuum pump can be used.
  • dry running vacuum pumps are preferably used here, for example.
  • the escaping on the pressure side of the pump gas stream is passed through a further heat exchanger, which is preferably cooled with brine at a temperature of about 0 to about 15 0 C.
  • This condensing ingredients are also collected in the sump, which already catches the condensates obtained under vacuum conditions.
  • the condensation carried out on the pressure side of the vacuum pump can take place, for example, through a heat exchanger, but also with a cascade of two or more heat exchangers arranged in series in parallel. After this Condensation step remaining gaseous substances are removed and any other recycling, for example, a thermal utilization, fed.
  • the collected condensates can also be reused as desired. However, it has proved extremely advantageous from an economical point of view to recycle the condensates into the reaction to produce acetone cyanohydrin. This is preferably done at one or more locations allowing access to the loop reactor.
  • the condensates may in principle have any composition, provided that they do not interfere with the production of the acetone cyanohydrin. In many cases, however, the majority of the condensate will consist of acetone and hydrocyanic acid, for example in a molar ratio of from about 2: 1 to about 1: 2, often in a ratio of about 1: 1.
  • acetone cyanohydrin is first cooled by a first heat exchanger by the supplied, cold crude acetone cyanohydrin to a temperature of about 40 to about 80 0 C. Subsequently, the
  • Acetone cooled via a least a further heat exchanger to a temperature of about 30 to about 35 0 C and optionally stored.
  • the acetone cyanohydrin in a rectification column at least from impurities having a boiling point of more than about -5 0 C and less than about 100 0 C, for example more than about 0 0 C and less than about 90 0 C, is freed, and these impurities are recycled into the reaction to produce acetone cyanohydrin.
  • the corresponding process variant is advantageously carried out with the aid of a device comprising a rectification column for removing constituents having a boiling point of more than -5 0 C and less as 100 0 C from the prepared acetone cyanohydrin and the rectification column is fluidly connected in such a way with the plant element for the production of acetone cyanohydrin, that the removed components can be returned to the reaction for the preparation of acetone cyanohydrin.
  • the acetone cyanohydrin produced in the first step is subjected to hydrolysis.
  • methacrylamide forms as product after a series of reactions.
  • the reaction is effected in a manner known to those skilled in the art by a reaction between concentrated sulfuric acid and acetone cyanohydrin.
  • the reaction is exothermic, so that reaction heat can be removed from the system, for example, for the reaction control.
  • the reaction can also be carried out here again in a batch process or in continuous processes. The latter has proved advantageous in many cases. If the reaction is carried out as part of a continuous process, the use of loop reactors has proven itself. The reaction can be carried out, for example, in only one loop reactor. However, it may be advantageous if the reaction is carried out in a cascade of two or more loop reactors.
  • a suitable loop reactor in the described process comprises one or more feed sites for acetone cyanohydrin, one or more concentrated sulfuric acid feed stations, one or more gas separators, one or more heat exchangers, and one or more mixers.
  • the hydrolysis of acetone cyanhydrin with sulfuric acid to methacrylamide is, as already described, exothermic.
  • the heat of reaction arising in the context of the reaction can advantageously be at least substantially removed from the system such that a
  • Yield maximization can be achieved because with increasing temperature in the reaction, the yield decreases. It is basically possible to achieve a rapid and comprehensive removal of the heat of reaction with appropriate heat exchangers. However, it may be advantageous not to cool the mixture too much, since a sufficient heat transfer is required for a corresponding exchange at the heat exchangers. Since the viscosity of the mixture increases with decreasing temperature, circulation in the loop reactor can be made more difficult if the temperature is too high. In this case, if appropriate, a sufficient removal of the reaction energy from the system can no longer be guaranteed.
  • a part, for example about two thirds to about three quarters, of the volume flow can be introduced from a stream of acetone cyanohydrin into a first loop reactor.
  • a first loop reactor may have one or more heat exchangers, one or more pumps, one or more mixing elements and one or more gas separators.
  • the passing through the first loop reactor Circulating flows are for example in the range of about 100 to 450 m 3 / h, preferably in a range of 200 to 400 m 3 / h and moreover preferably in a range of about 250 to 350 m 3 / h.
  • the recirculation streams are preferably in a range of about 40 to 450 m 3 / h, preferably in a range of 50 to 400 m 3 / h and moreover preferably in a range of about 60 up to 350 m 3 / h.
  • about 1 to 10 0 C are preferred as the temperature difference across the heat exchanger, with about 2 to 7 0 C are particularly preferred.
  • the supply of acetone cyanohydrin can in principle be carried out at any point in the loop reactor. However, it has proven to be advantageous if the supply takes place in a mixing element, for example in a mixer with moving parts or a static mixer.
  • the supply of sulfuric acid is advantageously carried out before
  • the ratio of reactants in the loop reactor is controlled so that there is an excess of sulfuric acid.
  • Excess sulfuric acid may be about 1, 8: 1 to about 3: 1 in the first loop reactor, and about 1.3: 1 to about 2: 1 in the last loop reactor, in terms of the molar ratio of the ingredients.
  • the sulfuric acid can be used here as a solvent and keep the viscosity of the reaction mixture low, whereby a higher removal of heat of reaction and a lower temperature of the reaction mixture can be ensured. This can bring significant yield advantages.
  • the temperature in the reaction mixture is about 90 to about 120 0 C, for example about 95 to about 115 0 C.
  • the heat removal can be ensured by one or more heat exchangers in the loop reactor. It has often proven to be advantageous if the heat exchangers have a suitable sensor for adjusting the cooling capacity in order to prevent excessive cooling of the reaction mixture for the reasons mentioned above.
  • the loop reactor should also have at least one gas separator. On the one hand the loop reactor continuously formed product is removed via the gas separator. On the other hand, gases formed during the reaction can thus be withdrawn from the reaction space. The gas is mainly carbon monoxide.
  • the product taken from the loop reactor is preferably transferred to a second loop reactor.
  • the reaction mixture containing sulfuric acid and methacrylic acid amide, as obtained by the reaction in the first loop reactor, is reacted with the remaining partial stream of acetone cyanohydrin.
  • the excess of sulfuric acid from the first loop reactor, or at least part of the excess sulfuric acid reacts with the acetone cyanohydrin with further formation of methacrylamide.
  • the implementation of the reaction in two or more loop reactors has the advantage that due to the sulfuric acid excess in the first loop reactor, the pumpability of the reaction mixture and thus the heat transfer and ultimately the yield can be improved.
  • at least one mixing element, at least one heat exchanger and at least one gas separator arranged.
  • the reaction temperature in the second loop reactor is also about 90 to about 120 ° C.
  • the second loop reactor has a heat exchanger whose cooling capacity can be controlled by appropriate sensors.
  • the supply of acetone cyanohydrin is again carried out in a suitable mixing element, preferably in a static mixer.
  • the product is removed and heated to a temperature of about 140 to about 180 0 C to complete the reaction and to form the methacrylamide.
  • the heating is preferably carried out such that the maximum temperature is achieved only for the shortest possible time period, for example for a time of about one minute to about 30 minutes, in particular for a time of about two to about eight or about three to about five minutes.
  • This can basically be done in any apparatus to achieve such a temperature for such a short period of time.
  • the power can be supplied conventionally by electrical energy or by steam.
  • the heat exchanger may, for example, with one or more
  • Combined gas separators it is possible, for example, to lead the reaction mixture after leaving the first coiled tubing in the heat exchanger through a gas separator. In this case, for example, formed during the reaction, gaseous components are separated from the reaction mixture. It is also possible to treat the reaction mixture after leaving the second coil with a gas separator. It may also be advantageous to treat the reaction mixture with a gas separator at both points, both after leaving the first and after leaving the second coiled tubing.
  • the amide solution thus obtainable generally has a temperature of more than 100 0 C, usually a temperature of about 140 to 180 0 C.
  • the resulting gaseous compounds in the amidation can basically be disposed of in any way or fed to a further processing. In some cases, however, it may be advantageous if the corresponding gases are combined in a transport line in such a way that they can be subjected either continuously or if necessary, if necessary, to pressure, for example with steam pressure, and thus transported onward.
  • Production of methacrylamide amide resulting gaseous products are introduced in the context of further transport into the reaction mixture of the below-described esterification. It can be one Initially done at any point in the esterification. Often, however, it is advantageous, especially when an esterification takes place in several Keseln to initiate the resulting gaseous products in the reaction mixture of the esterification, which is a first boiler.
  • the introduction of the resulting gaseous products for example, be designed so that the steamed gases are introduced into a boiler so that they provide for at least local mixing of the boiler contents or for heating the boiler contents or for a substantially constant temperature of the boiler contents or provide for a combination of two of said elements.
  • Another step of the invention is the hydrolysis of methacrylamide to methacrylic acid and their simultaneous esterification to methacrylic acid ester.
  • This reaction can be carried out in one or more heated, for example steam-heated boilers. It has proved advantageous in many cases if the esterification is carried out in at least two successive boilers, but for example also in three or four or more successive boilers.
  • a solution of methacrylamide is introduced into the boiler or in the first boiler of a two or more boiler cascade of boilers.
  • an amide solution as obtainable from the amidation reaction described here, can be fed into a first vessel.
  • the boiler is heated with steam, for example.
  • the supplied amide solution points in the Typically, an elevated temperature, for example, a temperature of about 100 to about 180 0 C, substantially corresponding to the discharge temperature of the amide solution from the amidation reaction presented above.
  • the boilers continue to be supplied with an alkanol, which can be used for esterification.
  • any alkanols having 1 to about 4 carbon atoms which may be linear or branched, saturated or unsaturated, are suitable here, with methanol being particularly preferred.
  • these alkanols can be used together with methacrylic acid esters, which is the case in particular in transesterifications.
  • the boiler is further charged with water, so that a total water concentration in the boiler of about 13 to about 26 wt .-%, in particular about 18 to about 20 wt .-% prevails.
  • the amount of amide solution and alkanol is controlled such that a total molar ratio of amide to alkanol of about 1: 1, 4 to about 1: 1, 6 prevails.
  • the alkanol can be distributed to the kettle cascade such that in the first reactor the molar ratio is about 1: 1, 1 to about 1: 1, 4 and in the following reaction stages based on the Automatamidstrom molar ratios of about 1: 0.05 to about 1 : 0.3 can be adjusted.
  • the alkanol fed into the esterification can be composed of "fresh alkanol" and alkanol from recycling streams of the work-up stages and, if required, also from recycling streams of the downstream processes of the production network.
  • the feeding of the first kettle with water can basically be carried out by supplying water from any source to the kettle, provided that this water has no ingredients which could adversely affect the esterification reaction or the subsequent process stages.
  • the boiler VE-water or well water can be supplied. It is, however, too possible to supply the boiler with a mixture of water and organic compounds, as obtained for example in the purification of methacrylic acid or methacrylic acid esters.
  • the boilers are at least partially charged with a mixture of water and such organic compounds.
  • the resulting gaseous substances in particular the methacrylic acid esters, can in principle be withdrawn from each vessel individually and fed to a purification.
  • the gaseous products from the first boiler are first fed into the second reaction vessel, without the gaseous compounds from the first boiler are fed directly to a cleaning.
  • This approach has the advantage that the often strong foaming in the first boiler does not have to be counteracted by expensive, defoaming apparatus.
  • the foam formed in the first tank and possibly entrained simply enters the reaction space of the second boiler. Since foaming is generally much lower there, it is not necessary to defoam the equipment.
  • first boiler second boiler now takes on the one hand the overflow of the first boiler, on the other hand it is fed with the gaseous substances formed in the first boiler or existing in the first boiler.
  • the second boiler and the possibly following are also charged with methanol. It is preferred that the amount of methanol from boiler to boiler by at least 10%, based on the previous boiler, decreases.
  • the water concentration in the second boiler and in the other boilers may differ from that of the first boiler, but often the concentration difference is small.
  • the vapors produced in the second boiler are removed from the boiler and introduced into the bottom of a distillation column.
  • the overflow of the second boiler is transferred to a third boiler and the overflow of the third boiler is transferred to a fourth boiler if necessary.
  • the other boilers are also steam-heated.
  • the temperature in the boilers 3 and optionally 4 is set to about 120 0 C to about 140 0 C.
  • the vapors escaping from the boilers are introduced into a distillation column, these preferably in the
  • the vapors comprise an azeotropic mixture of carrier vapor, methacrylic acid ester and alkanol and depending on the alkanol used have a temperature of about 60 to about 120 0 C, for example about 70 to about 90 0 C when using methanol.
  • the methacrylic acid ester is separated in gaseous form from the vapor components boiling at higher temperatures.
  • the high-boiling components mainly methacrylamide, hydroxyisobutyric acid ester and water
  • the methacrylic acid ester formed is withdrawn from the top of the column and cooled by a heat exchanger or a cascade of two or more heat exchangers.
  • the methacrylic acid ester formed can be cooled in the gaseous state via a first heat exchanger with water cooling. Both condensed and non-condensed materials are then transferred to a second heat exchanger, where further condensation via water cooling takes place.
  • gaseous substances can now be transferred into a separate, cooled with brine heat exchanger.
  • the condensate in this brine-cooled heat exchanger is then added to the distillate stream, while the remaining gaseous substances can be recycled or sent for disposal.
  • Heat exchanger is then cooled in a cooled with water or with sole heat exchanger to a temperature of less than 15 0 C, preferably about 8 to about 12 0 C.
  • This cooling step can lead to the methacrylic acid ester formed having a significantly lower formic acid content than would be the case without the corresponding cooling step.
  • the cooled condensate is then transferred to a phase separator.
  • the organic phase (methacrylic acid ester) is separated from the aqueous phase.
  • the aqueous phase which in addition to water may still have a content of organic compounds, in particular alkanol, from the distillation step, can in principle be used as desired. However, as already described above, it may be preferable that this mixture of water and organic compounds again in the Esterification process by feeding into the first reaction vessel takes place.
  • the separated organic phase is fed to a scrubber. There, the methacrylic acid ester is washed with demineralized water.
  • the separated aqueous phase which contains a mixture of water and organic compounds, in particular alkanol, can in principle be used in any other way. However, it is advantageous from an economic point of view to recycle this aqueous phase back into the esterification step, for example, by feeding it into the first kettle.
  • methacrylic acid esters have a strong tendency to undergo polymerization, it is advantageous in many cases when, in the course of the esterification of methacrylic acid, care is taken to prevent such polymerization.
  • the material streams can be mixed with stabilizers in such a way that the least possible polymerization takes place in the system itself.
  • the part of the plant is supplied with appropriate stabilizers in which the methacrylic acid or the methacrylic acid ester is present during or after the distillation in high concentration.
  • Methacrylic acid ester to supply a stabilizer. Furthermore, it has proved to be advantageous to rinse those parts of the plant with a solution of stabilizer in methacrylic acid esters in which methacrylic acid or methacrylic acid ester with a temperature of more than about 20 0 C, preferably at a temperature in the range of about 20 to about 120 0 C. circulated.
  • part of the condensate accumulating in the heat exchangers, together with a suitable stabilizer is returned to the top of the distillation column in such a way that the column head is continuously sprayed on its inside with stabilized methacrylic acid ester or stabilized methacrylic acid.
  • Methacrylic acid esters are acted upon in such a way that here no quiet zones can be trained.
  • the MMA obtained in the course of the esterification and the subsequent pre-cleaning or the methacrylic acid ester obtained or the resulting methacrylic acid are then fed to a further treatment. From the esterification results as remaining residue dilute sulfuric acid, which can also be fed to a further recovery.
  • the subject matter of the present invention can also be used in connection with a process for the prepurification of methacrylic acid or methacrylic acid ester, as described in the following process element.
  • a process for the prepurification of methacrylic acid or methacrylic acid ester as described in the following process element.
  • crude methacrylic acid or a crude methacrylic acid ester is subjected to further purification in order to arrive at a product which is as pure as possible.
  • Such a further process element representing cleaning for example, be single-stage.
  • it has proven to be advantageous in many cases if such a purification comprises at least two stages, wherein in a first pre-cleaning, as described herein, the low-boiling constituents of the product are removed.
  • crude methacrylic acid ester or crude methacrylic acid is first transferred to a distillation column in which the low-boiling constituents and water can be separated off.
  • the crude methacrylic acid ester is fed to a distillation column, the addition being carried out approximately in the upper half of the column.
  • the column bottom is heated with steam, for example, such that a wall temperature of about 50 to about 120 0 C is reached.
  • the cleaning is carried out under vacuum.
  • the pressure within the column is preferably about 100 to about 600 mbar in the case of the ester.
  • the pressure within the column is preferably about 40 to about 300 mbar in the case of the acid.
  • the low-boiling components are removed.
  • these may be, for example, ether, acetone and methyl formate.
  • the vapors are then condensed via one or more heat exchangers.
  • it has proven useful, for example, first to carry out a condensation via two series-connected, water-cooled heat exchangers.
  • the heat exchangers are preferably operated in a vertical state to increase the flow rate and to prevent the formation of stationary phases. Downstream of the water-cooled heat exchanger or water-cooled heat exchangers may be a brine-cooled heat exchanger, but it is also possible to connect a cascade of two or more brine-cooled heat exchangers.
  • the vapors are condensed, provided with stabilizer and fed, for example, a phase separator. Since the vapors can also contain water, any accumulating aqueous phase is disposed of or sent for further use.
  • the return in an esterification reaction for example, in an esterification reaction as described above, offers.
  • the aqueous phase is preferably recycled to the first esterification vessel.
  • the separated organic phase is fed as reflux into the top of the column. Part of the organic phase can in turn be used to spray the heat exchanger heads and the column head. Since the separated organic phase is a phase which is mixed with stabilizer, it is possible to do so effectively prevent the formation of quiet zones on the one hand. On the other hand, the presence of the stabilizer causes a further suppression of the polymerization tendency of the separated vapors.
  • the condensate stream obtained from the heat exchangers is preferably mixed with demineralized water in such a way that a sufficient separation effect can be achieved in the phase separator.
  • the gaseous compounds remaining after the condensation in the heat exchanger cascade can, preferably by means of vapor ejectors as negative pressure generators, again be subjected to condensation via one or more further heat exchangers. It has been found to be advantageous from an economic point of view, if not only the gaseous substances from the pre-cleaning are condensed in the context of such a post-condensation. Thus, it is possible, for example, to supply further gaseous substances to such after-condensation, as they result from the main purification of methacrylic acid esters.
  • the advantage of such a procedure is, for example, that a proportion of methacrylic acid ester, which was not condensed in the context of the main purification stage, can be transferred again via the phase separator into the purification column during the pre-purification.
  • a maximization of yield can take place, and the lowest possible losses of methacrylic ester occur.
  • the composition of the exhaust gas leaving this heat exchanger in particular the content of low boilers, can be adjusted by suitably selecting the design and operation of this further heat exchanger.
  • the water content in the esterification and the concentration of low-boiling constituents in the crude Methyl methacrylate increase continuously.
  • this discharging can take place, for example, in an order of magnitude in which water is supplied to the system in the pre-cleaning.
  • the deposited in the phase separator aqueous phase usually has a content of organic ingredients. It may therefore be advantageous to supply this water to a form of disposal which exploits this content of organic matter.
  • the crude, prepurified methacrylic acid ester is subjected to a redistillation.
  • the crude methacrylic acid ester is freed from its high-boiling constituents with the aid of a distillation column to obtain a pure methacrylic acid ester. This is the raw
  • Methacrylic acid ester introduced in a manner known to those skilled in the lower half of a distillation column.
  • the distillation column can correspond to any embodiment which appears suitable to a person skilled in the art. However, it has proven to be advantageous for the purity of the product obtained in many cases, if the distillation column with one or several packs, which corresponds approximately to the following specifications:
  • the columns can be spray units designed for spraying the column internals
  • the column internals can interconnect with one another or with the column via interrupted adhesive seams
  • Such adhesive seams have at least about 2, preferably at least about 5 and most preferably at least about 10 interruptions to 1 m adhesive seam length.
  • the length of these breaks may be selected to be at least about 10, preferably at least about 20, and most preferably at least about 50%, but generally not more than 95% of the length of the adhesive seam
  • Another constructional measure may be that less than about 50%, preferably less than about 25% and particularly preferably less than about 10% of all surfaces, in particular of column internals, are horizontal in the inner column regions, in particular those which come into contact with the methacrylic acid ester run.
  • the opening into the interior of the column neck can be configured conically or with inclined surfaces.
  • a Measure consist in keeping the amount of liquid of methacrylic acid ester during operation of the column in the column bottom as low as possible and on the other hand to avoid overheating of this amount despite moderate temperatures and large evaporation surfaces during evaporation.
  • the amount of liquid in the column bottom may be in the range from about 0.1 to 15% and preferably about 1 to 10% of the total amount of methacrylic acid ester in the column.
  • the measures proposed in this section can also be used in the distillation of methacrylic acid.
  • the column bottom is heated with steam.
  • the bottom temperature is preferably about 50 to about 80 0 C, in particular about 60 to about 75 0 C at a wall temperature of less than about 120 0 C.
  • the material obtained in the bottom of the column is preferably removed continuously and via a heat exchanger or a cascade of several heat exchangers to a temperature in a range from about 40 to about 80 0 C, preferably about 40 to about 60 0 C and more preferably in a range of about 50 to 60 0 C cooled.
  • This material predominantly methacrylic acid ester
  • a storage container for example, disposed of or otherwise used. It has proven advantageous in many cases if the material obtained in the column bottom is returned to the esterification reaction. For example, the material is recycled from the bottom of the column in the first esterification boiler. This has the advantage that in terms of the most economical driving and a As high yield contained in the bottom of the column, higher-boiling compounds are attributed to the esterification reaction.
  • the purified by distillation methacrylic acid ester is removed and cooled by a heat exchanger or a cascade of two or more heat exchangers.
  • the heat of the vapors can be dissipated by water-cooled heat exchangers or by brine-cooled heat exchangers or by a combination of both. It has proven useful in some cases if the vapors from the distillation column in two or more parallel
  • Heat exchangers are transferred, which are operated by means of water cooling.
  • the non-condensed fractions from the water-cooled heat exchangers can be introduced, for example, into a brine-cooled heat exchanger or a cascade of two or more brine-cooled heat exchangers, which can be arranged in series or in parallel.
  • the condensates obtainable from the heat exchangers are introduced into a collecting tank and fed by means of a pump via a further heat exchanger or a cascade of two or more further heat exchangers to a buffer tank.
  • the condensate stream is, for example, via a cascade of one or two water-cooled heat exchangers and one or two brine-cooled heat exchangers to a temperature in a range of about 0 to about 20 0 C, preferably about 0 to about 15 0 C and more preferably in a range of cooled down about 2 to 10 0 C.
  • the condensate stream is taken from a partial stream, which is returned via the top of the column in the distillation column.
  • the feeding of the condensate stream into the column head can take place in any desired manner, for example via distributors.
  • stabilizer is introduced into the top of the column with this feed.
  • a further partial stream of the condensate provided for recycling into the column can be branched off, for example, before introduction into the vapor line and introduced directly into the top of the column. Again, it is preferred that is introduced with this feed stabilizer in the top of the column.
  • the introduction into the column head can take place, for example, in such a way that the interior of the column head is sprayed with the condensate in such a way that no quiet zones can form in the column head at which polymerization of the methacrylic acid ester can take place. It may also be advantageous if a stabilizer to prevent polymerization is added to a partial flow of condensate returned to the column.
  • non-condensable gaseous substances are supplied for disposal, for example.
  • the crude product contained in the buffer tank is maintained at a temperature of about 0 to about 20 0 C, preferably about 0 to about 15 0 C and more preferably in a range of about 2 to 10 0 C with the aid of a brine cooler.
  • the product may be subjected to an adsorptive purification step. It has proven, for example, when the pure product is completely purified or at least a portion of the pure product using a molecular sieve on. Particularly acidic impurities, in particular formic acid formed during the production process, can thus be removed from the product stream in a simple manner.
  • the material streams occurring in the course of workup predominantly comprise polymerizable compounds.
  • the material streams occurring in the course of workup predominantly comprise polymerizable compounds.
  • Alkyl methacrylates and these substances are then condensed by cooling, leaving non-condensed residues in the gas phase, -
  • main cleaning substances are separated, which have a higher boiling point than the alkyl methacrylate and this is condensed by cooling, with non-condensed residues remain in the gas phase and
  • a condensate obtained in such a joint after-condensation can advantageously be subjected to a phase separation, wherein an aqueous and an organic phase can form.
  • the aqueous phase can be wholly or partially recycled to the esterification or the organic phase can be wholly or partially recycled to the pre-cleaning or both.
  • the total product obtained in the purification stage is then removed at a temperature in the range of about -5 to about 20 0 C, preferably about 0 to about 15 0 C and more preferably in a range of about 2 to 10 0 C of the purification stage ,
  • a stream of spent sulfuric acid as can be obtained from the esterification, be subjected to steam in a flotation tank.
  • a flotation tank In this case, at least part of the solids contained can deposit on the surface of the liquid, wherein these separated solids can be removed.
  • the vapors are then condensed in a heat exchanger, preferably with water cooling, cooled and returned to the esterification reaction.
  • the stripping occurring, non-condensable gaseous compounds are fed to any further use or disposed of.
  • the present invention furthermore relates to the use of the methacrylic acid obtainable by the process according to the invention or the methacrylic acid ester obtainable by the process according to the invention in fibers, films, paints, molding compositions,
  • the present invention relates to fibers, films, coatings, molding compositions, moldings, paper auxiliaries, leather auxiliaries, flocculants and drilling additives which are based on a methacrylic acid obtainable by the process according to the invention or a methacrylic acid ester obtainable by the process according to the invention.
  • Fig. 1 an apparatus for manufacturing and processing of
  • FIG. 2 shows schematically a plant for the production of acetone cyanohydrin
  • FIG. 3 shows schematically a reprocessing plant of acetone cyanohydrin
  • Fig. 7 The fine cleaning system of the ester.
  • Fig. 1 the preferred elements are shown a plant composite 1 for the production of methacrylic acid or methacrylic acid esters and their processing products.
  • the system composite 1 has various interconnected mostly fluid-conducting systems as elements of this composite.
  • This composite includes acetone cyanohydrin production 20, followed by acetone cyanohydrin work-up 30, followed by amidation 40, followed by esterification / hydrolysis 50 / 50a), followed by work-up for ester or methacrylic acid 60, again followed by a finely-cleaned 70, after which Ester, usually methyl methacrylate, or methacrylic acid is present.
  • the pure ester / pure acid thus obtained can be fed to a further processing plant 80.
  • Suitable further processing plants 80 are, in particular, polymerization apparatuses and reactors for further organic reactions.
  • Polymethacrylates can be prepared in the polymerization reactors, and in the reactors for organic reactions, the pure monomers obtained here can be converted into further organic compounds.
  • the further processing products are polymers of methacrylic acid or methacrylic acid esters, in particular methyl methacrylate, these are transformed into fibers, molding compositions, in particular granules, films, plates, automobile parts and other shaped articles by suitable processes Equipment such as extruders, blow extruders, injection molding equipment, spinnerets and the like, further processed.
  • the system composite 1 in many cases includes a sulfuric acid plant 100.
  • Sulfuric acid 2 supplied with concentrated sulfuric acid.
  • the dilute sulfuric acid also referred to as "spent acid” from the esterification 50 (hydrolysis 50a) is transferred to the sulfuric acid plant 100 through the spent sulfuric acid lines 4 and 5, respectively.
  • the dilute sulfuric acid can be worked up in the sulfuric acid plant 100.
  • the dilute sulfuric acid can be worked up, for example, as described in WO 02/23088 A1 or WO 02/23089 A1
  • Hydrocyanic acid tank 22 is provided.
  • the acetone container 21 has a washing tower 23, which has one or more cooling elements 24 in its upper region.
  • In the wash tower 23 opens a series of Exhaust pipes 25, which come from different systems of the system composite 1.
  • a loop reactor 26 the acetone is fed via the acetone feed line 27 and the hydrocyanic acid via the hydrocyanic acid feed line 28 downstream of the hydrocyanic acid feed line 28 there is a pump 29, again followed by a catalyst feed 210, followed by a static mixer 211.
  • the reaction mixture consisting of acetone, hydrocyanic acid and catalyst is driven to a considerable extent in a cycle which is characterized by bold lines.
  • the reaction mixture is passed over the flow resistance along the cooling lines 214 and a part of the circulating stream passed into another heat exchanger 215, followed by a collecting tank 216, in which a nozzle 217 as part of a cooling circuit 218 with a heat exchanger 219th is located, whereby the reaction product is held on the one hand in motion and the other cool.
  • a stabilizer tank 221 is connected via a discharge line 220 adjoining the collecting tank 216, to which a sulfuric acid feed line 222 opens and from which the crude acetone cyanohydrin is passed through the discharge line 223 into the acetone cyanohydrin work-up 30.
  • the derivative 223 discharges from cyanohydrin production 20 into a heat exchanger 31, in which the stream coming from cyanogen 20 is heated.
  • the heat exchanger 31 is followed by a vapor feed line 32, which opens into the upper, preferably the top region of a column 33.
  • the column 33 has a plurality of packages 34, which are usually designed as trays.
  • In the lower region of the column 33 there is the column sump 35, from which a sump discharge 36 leads into the heat exchanger 31 and heats the streams conducted via the discharge line 233 into the heat exchange 31.
  • To the heat exchanger 31 is followed by a pure product guide 37, followed by the amidation 40 downstream.
  • a head discharge 38 which opens into a heat exchanger 39, which is followed by a vacuum pump 310, which in turn opens into a heat exchanger 311.
  • Both the heat exchanger 39 and the heat exchanger 311 are connected via lines to a cooling tank 312, which is followed by a recycle 313, which is connected to the loop reactor 26 in the acetone cyanohydrin production 20.
  • the amidation 40 shown in FIG. 4 initially has a
  • Acetoncyanhydrinzu Adjustment 41 and a sulfuric acid feed 42 which open into a loop reactor 43.
  • the acetone cyanohydrin feed 41 which is connected to the acetone cyanohydrin work-up 30, flows into the loop of the loop reactor 43 after a pump 44 in front of a mixer 45.
  • the sulfuric acid feed 42 ends before this pump 44.
  • a heat exchanger 46 follows, which in turn discharges into a gas separator 47 on the one hand, a gas outlet 48 and a supply line 49 to another loop reactor 410 goes off.
  • the further loop reactor 410 or a third is comparable to the first loop reactor 43 constructed.
  • a feed line 411 passes into a heat exchanger 412, followed by a gas separator 413, from which leads to a gas outlet 414 and an amide line 415 leading to the esterification / saponification 50 / MAS unit 50a.
  • FIG. 5 shows the esterification 50 in which a solvent line 51 leading to water and organic solvents and an amide line 52 connected to the amidation 40 open into a vessel 53 which can be heated by a boiler heater 54.
  • a boiler heater 54 In the boiler 53 further opens a dashed lines drawn alcohol pipe 55.
  • the alcohol pipe 55 opens into both the upper and in the lower part of the boiler 53.
  • the first boiler 53 is connected to a further boiler 53 ', which has a further boiler heater 54'.
  • This further boiler 53 ' is connected to the alcohol pipe 55 both from below and from above.
  • the ester vapor line 56 connects, which opens into a sump 57 of a column 58.
  • a boiler unit 510 framed in the dotted ellipse is formed from a heatable vessel 53 and 54 with alcohol pipe 55 and ester vapor line 56.
  • One, two or more of such boiler units may follow each other in a cascade, with each of these boiler units 510 being connected via the ester vapor line 56 to the bottom 57 of the column 58. From the bottom 57 of the column 58 further leads a heavy soother line 511 to the boiler 53 to supply water and organic solvents again the esterification.
  • a first stabilizer feed 414 stabilizer labeled "S”
  • a further stabilizer feed 515 may be provided to supply an undesired polymerization preventing inhibitor or stabilizer to the further phase separator 513 is followed by a scrubber 516, in the lower region of which passes a solvent line 517 which opens into the solvent line 51 via a heat exchanger 521.
  • a crude ester line is discharged, which discharges into the ester processing 60 the upper portion of the boiler 53 'and the boiler of the last boiler unit 510 outgoing donor acid conduit 59 opens into a flotation tank 519 for separating the solids or in the
  • the ester workup shown in FIG. 6 is followed by a crude ester line 61 to the esterification 50, the crude ester feed line 61 discharging into the middle region of a vacuum distillation column 62.
  • This column 62 has column internals 63 and a bottom heater 64 arranged in the lower region of the column 62.
  • an ester derivative 65 From the lower region of the column 62, which represents the bottom of this column, is an ester derivative 65, which opens into the fine ester cleaning 70 and thus freed from low boilers crude ester feeds the fine cleaning.
  • a first heat exchanger 66 and a further or a plurality of heat exchangers 67 adjoin via a discharge, followed by a phase separator 69.
  • phase separator 69 the mixture originating from the heat exchanger 67 is divided into organic and aqueous constituents, with a recycle 611 in the upper region adjoining the phase separator 69, which opens in the upper region of the column 62.
  • a water outlet 610 In the lower part of the separator there is a water outlet 610, which opens into the esterification 50 in order to recycle the separated water to the esterification.
  • a vacuum generator 613 Connected to the heat exchangers 66 and 67 via a vacuum line 612 is a vacuum generator 613.
  • the ester derivative 65 originating from the ester workup 60 discharges into a distillation column 71.
  • This comprises a plurality of column internals 71 and a bottom sump heater 73 at the bottom of the distillation column 71.
  • a clean ester vapor line 74 passes into a first heat exchanger 75 onto which one (or more) further heat exchanger 76 follow, which are connected to a vacuum generator 717.
  • the outlet of the further heat exchanger 76 has a line from which, on the one hand, an ester recycle line 77 opens into the upper region of the top of the distillation column 71.
  • the ester recycle 77 has a stabilizer feed 79, which is arranged in the ester recycle line 77 in front of a mixer 78.
  • a stabilizer feed 79 which is arranged in the ester recycle line 77 in front of a mixer 78.
  • an additional heat exchanger 711 and another heat exchanger 712. Connected to these in series, an additional heat exchanger 711 and another heat exchanger 712. This is followed by a molecular sieve container 713 having molecular sieve packages 714. Further purified by the molecular sieve, the pure test ester is transferred to the further processing plant 80 by the pure ester ester removal following the molecular sieve container.

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  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Abstract

L'invention concerne principalement un procédé de fabrication d'esters alkyliques de l'acide méthacrylique, ledit procédé comprenant au moins les étapes suivantes : fabrication de cyanhydrine d'acétone à partir d'acide cyanhydrique et d'acétone lors d'une première étape, purification de la cyanhydrine d'acétone lors d'une deuxième étape, fabrication d'un amide de l'acide méthacrylique à partir de la cyanhydrine d'acétone lors d'une troisième étape, estérification d'un mélange réactionnel contenant l'amide de l'acide méthacrylique et au moins un alcool alkylique en présence d'un mélange d'eau et d'acide sulfurique pour former un ester alkylique de l'acide méthacrylique lors d'une quatrième étape et purification de l'ester alkylique de l'acide méthacrylique lors d'au moins une étape supplémentaire. L'invention concerne également un dispositif pour la réalisation de ce procédé.
EP07803110A 2006-12-08 2007-08-31 Procede integre et dispositif pour la fabrication d'esters d'acide methacrylique a partir d'acetone et d'acide cyanhydrique Withdrawn EP2054370A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006058250A DE102006058250A1 (de) 2006-12-08 2006-12-08 Integriertes Verfahren und Vorrichtung zur Herstellung von Methacrylsäureestern aus Aceton und Blausäure
PCT/EP2007/059110 WO2008068064A1 (fr) 2006-12-08 2007-08-31 Procédé intégré et dispositif pour la fabrication d'esters d'acide méthacrylique à partir d'acétone et d'acide cyanhydrique

Publications (1)

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EP2054370A1 true EP2054370A1 (fr) 2009-05-06

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EP07803110A Withdrawn EP2054370A1 (fr) 2006-12-08 2007-08-31 Procede integre et dispositif pour la fabrication d'esters d'acide methacrylique a partir d'acetone et d'acide cyanhydrique

Country Status (12)

Country Link
US (1) US20100069662A1 (fr)
EP (1) EP2054370A1 (fr)
JP (1) JP2010511651A (fr)
KR (1) KR20090096450A (fr)
CN (1) CN101195574A (fr)
AU (1) AU2007327788A1 (fr)
BR (1) BRPI0719692A2 (fr)
DE (1) DE102006058250A1 (fr)
MX (1) MX2009005895A (fr)
RU (1) RU2009125683A (fr)
TW (1) TW200835680A (fr)
WO (1) WO2008068064A1 (fr)

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DE102012205257A1 (de) 2012-03-30 2013-10-02 Evonik Röhm Gmbh Verfahren zur Hydrolyse von Acetocyanhydrin

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DE102008000785A1 (de) * 2008-03-20 2009-09-24 Evonik Röhm Gmbh Verfahren zur Herstellung von Methacrylsäure
DE102008000787A1 (de) * 2008-03-20 2009-09-24 Evonik Röhm Gmbh Verfahren zur Aufreinigung von Methacrylsäure
DE102009002592A1 (de) * 2009-04-23 2010-10-28 Evonik Röhm Gmbh Dosierring
DE102011076642A1 (de) * 2011-05-27 2012-11-29 Evonik Röhm Gmbh Verfahren zur Herstellung von Methacrylsäure
WO2014051971A1 (fr) * 2012-09-28 2014-04-03 Rohm And Haas Company Procédé de production de mma et/ou de maa à partir de cyanohydrine d'acétone et d'acide sulfurique
EP3212603B1 (fr) 2014-10-27 2020-11-25 Rohm and Haas Company Procédé à encrassement réduit pour la production de méthacrylate de méthyle
EP3212604B1 (fr) 2014-10-27 2020-11-25 Rohm and Haas Company Procédé pour la production de méthacrylate de méthyle avec réduction d'encrassement
EP3392237B1 (fr) 2017-04-21 2019-10-02 Evonik Degussa GmbH Procédé destiné à la fabrication de cyanhydrine de l'acroléine
JP2021113378A (ja) * 2020-01-21 2021-08-05 村田機械株式会社 空気紡績機
WO2021197636A1 (fr) * 2020-04-03 2021-10-07 Rockwool International A/S Procédé de production de lignines oxydées et système de production de lignines oxydées
US20230174566A1 (en) * 2020-04-03 2023-06-08 Rockwool A/S Method for producing oxidized lignins and system for producing oxidized lignins
WO2021198467A1 (fr) * 2020-04-03 2021-10-07 Rockwool International A/S Procédé de drainage d'eau
US11690332B2 (en) 2020-04-03 2023-07-04 Rockwool A/S Method of growing plants
CN116348444A (zh) 2020-10-23 2023-06-27 罗姆化学有限责任公司 通过在转化过程中减少的返混而改进的用于制备甲基丙烯酸甲酯和/或甲基丙烯酸的方法
EP4100387B1 (fr) 2020-10-23 2023-05-31 Röhm GmbH Procédé optimisé de fabrication d'acide méthacrylique et/ou de méthacrylate d'alkyle par réduction des sous-produits interférents
CN116490488A (zh) 2020-10-23 2023-07-25 罗姆化学有限责任公司 通过减少干扰性副产物而优化的制备甲基丙烯酸烷基酯的方法
WO2023117754A1 (fr) 2021-12-23 2023-06-29 Röhm Gmbh Procédé de production de méthacrylates d'alkyle avec des rendements supérieurs et des émissions réduites en composés organiques volatils
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KR20090096450A (ko) 2009-09-10
DE102006058250A1 (de) 2008-06-12
CN101195574A (zh) 2008-06-11
JP2010511651A (ja) 2010-04-15
MX2009005895A (es) 2009-07-24
RU2009125683A (ru) 2011-01-20
BRPI0719692A2 (pt) 2013-12-24
AU2007327788A1 (en) 2008-06-12
TW200835680A (en) 2008-09-01
WO2008068064A1 (fr) 2008-06-12
US20100069662A1 (en) 2010-03-18

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