EP1718592A1 - Cleaving oligomeric (meth)acrylic acid in the liquid phase and under pressure - Google Patents
Cleaving oligomeric (meth)acrylic acid in the liquid phase and under pressureInfo
- Publication number
- EP1718592A1 EP1718592A1 EP05715401A EP05715401A EP1718592A1 EP 1718592 A1 EP1718592 A1 EP 1718592A1 EP 05715401 A EP05715401 A EP 05715401A EP 05715401 A EP05715401 A EP 05715401A EP 1718592 A1 EP1718592 A1 EP 1718592A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- acrylic acid
- meth
- splitting
- cleavage
- splitting agent
- 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- Withdrawn
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0059—General arrangements of crystallisation plant, e.g. flow sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
- B01D5/0033—Other features
- B01D5/0054—General arrangements, e.g. flow sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/24—Stationary reactors without moving elements inside
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/09—Preparation of carboxylic acids or their salts, halides or anhydrides from carboxylic acid esters or lactones
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
- B01D3/146—Multiple effect distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00002—Chemical plants
- B01J2219/00004—Scale aspects
- B01J2219/00006—Large-scale industrial plants
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
- B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
- B01J2219/00094—Jackets
Definitions
- the present invention relates to a process for the cleavage of (meth) acrylic acid oligomers in the liquid phase, the use of water, if appropriate with a protic compound as a cleaving agent for the cleavage of (meth) acrylic acid oligomers, a device for (meth) acrylic acid synthesis, the use of this device for the production of (meth) acrylic acid and (meth) acrylic acid which has been produced using this device.
- (Meth) acrylic acid is used in this text for the compounds with the nomenclature names "methacrylic acid” and "acrylic acid”. Of both compounds, acrylic acid is preferred according to the invention.
- oligomer (s) is used in this text for Related compounds that have two or more repeats of an atomic sequence in a molecule. This term includes in particular molecules which are based on at least two monomers, in particular (meth) acrylic acid.
- Acrylic acid is usually obtained by catalytic gas phase oxidation of propylene with an oxygen-containing gas.
- the propylene is first catalytically oxidized to acrolein, which is then converted to acrylic acid in a second stage using catalysts.
- the acrylic acid thus obtained is removed from the gaseous reaction mixture by absorption with water in the form of an aqueous solution.
- the acrylic acid is then purified by distillation of the acrylic acid solution in a rectification column, by extraction with suitable extraction agents or by crystallization processes.
- the synthesis of methacrylic acid is carried out in a comparable manner by catalytic oxidation of isobutylene, tert-butanol, methacrolein or isobutyraldehyde in the gas phase.
- (meth) acrylic acid oligomers has a disadvantageous effect in particular in the production of absorbent polymers and the absorbent polymers obtainable thereby.
- the amount of residual monomers present in the absorbent polymer after it has been produced increases. This is particularly disadvantageous when the absorbent polymers are used in the area of baby hygiene articles, since diapers place particularly high demands on the purity of the polymers used in the diapers.
- No. 4,317,926 describes the non-catalytic cleavage of acrylic acid dimers in the liquid phase at a pressure of 20 to 500 nmHg and at a temperature in a range from 120 to 220.degree.
- the residence times of the dimers in the cleavage reactor in a range from 3 to 8 hours are required.
- Inorganic copper compounds promote cleavage in the process described in this document.
- No. 5,734,075 describes the non-catalytic cleavage of acrylic acid dimers in the gas phase at a temperature in a range from 140 to 260 ° C.
- the monomer recovery rate improves in the process described in this document if mixtures of residues from acrylic acid synthesis and from acrylic acid ester synthesis are used.
- the residence time of the dimers in the cleavage reactor is between 0.5 and 3 hours, with up to 80% by weight of the dimers being cleaved. This document does not disclose that the cleavage is carried out under positive pressure.
- No. 3,086,046 describes the non-catalytic, continuous cleavage of acrylic acid at a pressure of 5 to 150 mHg and at a temperature in a range from 350 to 650 ° C.
- the residence time of the dimers in the can is in a range between 0.5 and 2 s.
- the process described in this document is only suitable for acrylic acid residues that have a low molecular weight (at most acrylic acid dimers).
- No. 3,868,410 describes the cleavage of oligomers which are formed in the esterification of acrylic acid monomers with an alcohol. The cleavage is carried out by reacting the bottom product formed in the esterification reaction with suitable acidic catalysts. The use of water in the cleavage reaction is not disclosed.
- EP-A-0 751 759 describes the catalytic cleavage of acrylic acid dimers in the gas phase by means of a circulation reactor with a fixed bed at a pressure in a range from 100 to 250 mbar and at a temperature in a range from 200 to 400 ° C. Oxides of alkali or alkaline earth metals, such as MgO, are used as catalysts.
- the object of the present invention was to provide a process for the cleavage of (meth) acrylic acid oligomers which is improved compared to the processes described in the prior art.
- the present invention was also based on the object of providing a process in which an effective oligomer cleavage can be made possible even without the addition of metallic catalysts.
- a further object on which the present invention is based was to provide a method with which (meth) acrylic acid esters or (meth) acrylic acid amides can be obtained in a targeted manner from (meth) acrylic acid oligomers.
- Another object underlying the present invention was to provide a process for the cleavage of (meth) acrylic acid oligomers which not only enables the cleavage of the oligomers into (meth) acrylic acid, but which also cleaves the oligomers to form monomeric ones (Meth) acrylic acid ester enables.
- Ri is a hydrogen atom or a - to C 10 -alkyl group, preferably a C 2 - to C 8 -alkyl group, particularly preferably a C 2 - to C -alkyl group,
- R 2 is a hydrogen atom or a methyl group
- n is an integer in a range between 1 and 20, preferably in a range from 1 to 15 and particularly preferably in a range from 1 to 10,
- the (meth) acrylic acid oligomers not at a pressure of at least 1 bar, preferably at least 10 bar and moreover preferably at least 80 bar, a pressure of 1,000 bar, particularly preferably 800 bar and more preferably 600 bar is exceeded, to a temperature of at least 50 ° C, particularly preferably to a temperature of at least 150 ° C and more preferably to a temperature of at least 250 ° C, a temperature of 500 ° C, particularly preferably of 400 ° C and moreover preferably not to be exceeded by 300 ° C, are heated.
- the (meth) acrylic acid oligomers are cleaved in the presence of a cleaving agent.
- the present invention accordingly also relates to a process for cleaving a (meth) acrylic acid oligomer of structure I
- Ri is a hydrogen atom or a - to C 10 -alkyl group, preferably a C 2 - to C 8 -alkyl group, particularly preferably a C 2 - to C 4 -alkyl group,
- R 2 is a hydrogen atom or a methyl group
- n is an integer in a range between 1 and 20, preferably in a range from 1 to 15 and particularly preferably in a range from 1 to 10,
- R 3 is a hydrogen atom, ad- to C 12 -alkyl group, particularly preferably a C 2 - to C 8 -alkyl group and moreover preferably a C 2 - to C -alkyl group, or else a -C x H 2x -OH group where x is a whole Number in a range from 1 to 12, preferably in a range from 2 to 8 and particularly preferably in a range from 2 to 4, and
- R is a hydrogen atom or a C1 to C 2 alkyl group, particularly preferably a C to C 8 alkyl group and moreover preferably a C 2 to C alkyl group, with the proviso that both radicals are not hydrogen atoms,
- the (meth) acrylic acid oligomer with the splitting agent at a temperature of at least 50 ° C, particularly preferably at a temperature of at least 150 ° C and more preferably at a temperature of at least 250 ° C, a temperature of 500 ° C , particularly preferably not exceeding 400 ° C. and more preferably 300 ° C., and at a pressure of at least 1 bar, preferably of at least 10 bar and more preferably of at least 80 bar, a pressure of 1,000 bar being particularly preferred preferably not exceeding 800 bar and more preferably not exceeding 600 bar, is brought into contact in the preferably liquid phase.
- a compound of structure II is used as the splitting agent, in which it is used
- Structure II is a mixture of at least two structurally different ones
- this mixture comprising at least 10, preferably at least 50 and particularly preferably at least 80 and more preferably at least 95% by weight, based in each case on the splitting agent
- Alcohols methanol, ethanol, 1-propanol, 2-propanol, tert-butanol, n-butanol, iso-butanol and sec-butanol and the diols ethylene glycol, propylene glycol,
- Mixtures are further preferred splitting agents of structure II from at least two of the above-mentioned splitting agents, in particular mixtures of water and ethanol or mixtures of water and butanol.
- mixtures of the previously defined splitting agent of structure II with other protic compounds in particular with splitting agents of structure III or also with polyols, can be used.
- the pressure and temperature conditions during the cleavage reaction are selected such that all the reactants involved in the cleavage reaction are at least partially liquid.
- the cleaving agent in which the cleavage takes place in the presence of a cleaving agent, it is preferred that the cleaving agent is brought into contact with the (meth) acrylic acid oligomer in the presence of a protic compound of structure II or of which is different from water Structure III, preferably structure II, takes place.
- this protic compound can be used instead of water and according to another embodiment of the method according to the invention in addition to the water, the latter embodiment being preferred.
- splitting agent and the (meth) acrylic acid oligomer in a weight ratio of splitting agent: (meth) acrylic acid oligomer in a range from 0.01: 1 to 10: 1, particularly preferably in one Range from 0.1: 1 to 8: 1 and more preferably in a range from 0.5: 1 to 6: 1.
- the cleaving agent in which the cleavage is carried out after adding a cleaving agent, is used in a molar amount which is at most 90%, preferably at most 80% and moreover preferably not more than 50% of the molar amount of (meth) acrylic acid which is bound in oligomeric form in the (meth) acrylic acid oligomers (two (meth) acrylic acid molecules in one dimer, three (meth) acrylic acid molecules in a trimer etc.).
- the splitting agent is used in a molar amount which is at least 50%, preferably at least 80% and moreover preferably at least 90% of the molar amount of (meth) acrylic acid which is in the (meth ) Acrylic acid oligomers is bound.
- cleaving agent if the addition of a cleaving agent is required to cleave the (meth) acrylic acid oligomers, the person skilled in the art will easily determine the amount of cleaving agent required for the cleavage by suitable preliminary tests. If, for example, pure water is used as a splitting agent in order to convert the (meth) acrylic acid oligomers into (meth) acrylic acid monomers, the person skilled in the art will add water until the most complete possible splitting has taken place under the selected pressure and temperature conditions or until no further formation of monomeric (meth) acrylic acid can be observed even with the further addition of water.
- alcohols of structure II are used as cleaving agents in order to convert the (meth) acrylic acid oligomers into the corresponding (meth) acrylic acid esters, the person skilled in the art will add these alcohols until the oligomers have been cleaved as completely as possible or until if alcohol is added further, monomeric (meth) acrylic acid or monomeric (meth) acrylic acid esters are no longer formed.
- the cleavage of the (meth) acrylic acid oligomer by means of compounds of structure II or structure III preferably results in monomeric compounds of structure IN FL OH ⁇ C - C - O FL H /
- R 6 is a hydrogen atom or a C 1 to C 2 alkyl group, particularly preferably a C 2 to C 8 alkyl group and moreover preferably a C 2 to C alkyl group, with the proviso that not both R 6 groups Are hydrogen atoms,
- R 5 is a hydrogen atom, a Q to C 12 alkyl group, particularly preferably a C 2 to C 8 alkyl group and moreover preferably a C 2 to C alkyl group, or else a -C x H 2x -OH group x is an integer in a range from 1 to 12, preferably in a range from 2 to 8 and particularly preferably in a range from 2 to 4;
- R 2 is a hydrogen atom or a methyl group.
- the (meth) acrylic acid oligomer is used in the form of a composition which comprises the process steps during the continuous process of (meth) acrylic acid synthesis i) catalytic oxidation of C 3 or C starting compounds in the gas phase, ii) absorption or condensation or both of the (meth) acrylic acid formed in water, and iii) processing of the aqueous (meth) acrylic acid solution thus obtained by distillation as the bottom product of the distillative Working up of the (meth) acrylic acid solution in process step iii) is obtained.
- a crystallization step iv) can be provided in the above process for (meth) acrylic acid synthesis instead of process step iii).
- the aqueous (meth) acrylic acid solution can be freed from impurities such as (meth) acrylic acid oligomers.
- the (meth) acrylic acid purified by the distillation can be further purified by removing impurities such as (meth) acrylic acid oligomers.
- Both embodiments have in common that the impurities such as (meth) acrylic acid oligomers accumulate in the mother liquors and effluents from these crystallization steps and can be fed to the process according to the invention for the cleavage of (meth) acrylic acid oligomers.
- the process according to the invention for the cleavage of (meth) acrylic acid oligomers can also be supplied with the composition which accumulates as waste in the swamps at the most diverse points in the (meth) acrylic acid synthesis during purification and separation steps.
- composition or this bottom product preferably has: ( ⁇ l) 0.1 to 70% by weight, particularly preferably 5 to 60% by weight and moreover preferably 10 to 50% by weight of monomeric (meth) acrylic acid, as ⁇ l connection, ( ⁇ 2) 1 to 90% by weight, particularly preferably 10 to 40% by weight and moreover preferably 20 to 30% by weight of (meth) acrylic acid dimers, as the ⁇ 2 compound,
- ( ⁇ 4) 0 to 20% by weight, particularly preferably 1 to 10% by weight and more preferably 2 to 8% by weight of water, as the ⁇ 4 compound, ( ⁇ 5) 1 to 92% by weight, particularly preferably 10 to 75% by weight and moreover preferably 40 to 57% by weight of oligomers which are larger than (meth) acrylic acid trimers, as the ⁇ 5 compound, and to
- ( ⁇ 6) 1 to 20% by weight, particularly preferably 2 to 15% by weight and moreover preferably 5 to 10% by weight of further, of the ⁇ l, ⁇ 2, ⁇ 3, ⁇ 4 and ⁇ 5 compounds various compounds, as by-products, the sum of components ( ⁇ l) to ( ⁇ 6) being 100% by weight.
- the by-products ( ⁇ 6) are preferably those
- C-Starting compounds such as isobutene, isobutane, tert-butanol or methacrolein, are formed in addition to the methacrylic acid.
- by-products include low-boiling organic compounds whose boiling point is below the
- the boiling point of acrylic acid is, such as acrolein, acetic acid or formaldehyde, and high-boiling organic compounds whose boiling point is above the boiling point of acrylic acid, such as maleic acid.
- the continuous Procedure is preferred.
- the bottom product obtained in the working up of the aqueous (meth) acrylic acid solution by distillation is continuously removed and, if the cleavage requires the addition of a cleaving agent, preferably transferred to a mixing device by means of a pump.
- a continuous removal of the bottom liquid in the sense of this invention means that the removal can take place either in portions at constant or non-constant time intervals or continuously at a constant speed.
- the splitting agent is also introduced into the mixing device, preferably by means of a pump. If a splitting agent mixture comprising at least two structurally different splitting agents is used, the individual splitting agents can be mixed separately from one another with the composition comprising the (meth) acrylic acid oligomer or else used together as a mixture in the process according to the invention.
- the components After the components have been mixed in the mixing device, they are brought to a temperature of at least 50 ° C., particularly preferably at a temperature of at least 150 ° C. and moreover preferably at a temperature of at least 250 ° C., a temperature of 500 ° C, particularly preferably not exceeding 400 ° C. and more preferably not exceeding 300 ° C.
- the heating is carried out at a pressure of at least 1 bar, preferably of at least 10 bar and moreover preferably of at least 80 bar, a pressure of 1,000 bar, particularly preferably 800 bar and more preferably 600 bar not being exceeded.
- the mixed components are preferably heated by means of a heat exchanger. It is also conceivable to first heat the individual components under the pressures mentioned above and then mix them together.
- This splitting device can be from Mixing device be spatially separated. However, it is also conceivable that the mixing of the components and the subsequent cleavage of the (meth) acrylic acid oligomers takes place in the same device unit.
- the (meth) acrylic acid oligomers are heated to the above-mentioned temperatures in the cleaving device without prior mixing with a cleaving agent and thus cleaved.
- the residence time of the (meth) acrylic acid oligomers in the cleavage reactor is preferably in a range from 0.1 seconds to 20 minutes, particularly preferably in a range from 1 second to 15 minutes and moreover preferably in a range from 1 to 10 minutes.
- the (meth) acrylic acid oligomer is therefore in the form of a Composition used, which during the process of (meth) acrylic acid
- step III) catalytic oxidation of C 3 or C 4 starting compounds in the gas phase, II) absorption or condensation or both of the (meth) acrylic acid formed in water to give an absorption product, III) optionally working up the aqueous (meth) acrylic acid solution thus obtained by distillation , and IN) purification of the absorption product or the concentrated (meth) acrylic acid solution obtained by distillation or both by crystallization, as mother liquor in the purification by crystallization in process step IV) is obtained. In one embodiment of the method according to the invention, this also includes step III) as mandatory.
- This mother liquor preferably has at most 65% by weight (meth) acrylic acid.
- the proportion of (meth) acrylic acid oligomers in the mother liquor is preferably in a range from 0.1 to 50% by weight, particularly preferably in a range from 0.5 to 50% by weight and moreover preferably in a range from 1 to 30% by weight, based in each case on the total weight of the composition.
- the mother liquor resulting from the crystallization of the (meth) acrylic acid solution is continuously removed and, if a splitting agent is added, preferably transferred to a mixing device by means of a pump.
- the removal of the mother liquor can be carried out either in portions at constant or non-constant time intervals or continuously at a constant rate if the process according to the invention is carried out continuously.
- the (meth) acrylic acid oligomers are cleaved in the presence of a catalyst.
- Preferred catalysts are metal catalysts such as catalysts based on antimony, cobalt or manganese, acid salts, inorganic acid catalysts such as sulfuric acid or hydrochloric acid, organic acid catalysts such as p-toluenesulfonic acid or methanesulfonic acid or both, hydroxides such as potassium hydroxide, lithium hydroxide, antimony hydroxides, cobalt hydroxides , Manganese hydroxides or lead hydroxides, metal salts such as zinc chlorides, or mixtures of at least two of them.
- the catalyst can be used in pure form or immobilized on a substrate, for example in combination with zeolites, which are preferably water-resistant, or ion exchange resins.
- zeolites which are preferably water-resistant, or ion exchange resins.
- the catalyst in an amount in a range from 1 to 5000 ppm, particularly preferably in an amount in a range from 10 to 2000 ppm and further preferably in an amount in a range from 100 to 1000 ppm, based on the (meth) acrylic acid oligomers, is used.
- the invention also relates to the use of compounds of structure II or structure III, preferably structure II, where R 3 and Rt are as defined above, as cleaving agents for cleaving (meth) acrylic acid oligomores of structure I at a temperature of at least 50 ° C, particularly preferably at a temperature of at least 150 ° C and moreover preferably at a temperature of at least 250 ° C, a temperature of 500 ° C, particularly preferably of 400 ° C and more preferably of 300 ° C not is exceeded, and at a pressure of at least 1 bar, preferably at least 10 bar and more preferably at least 100 bar, a pressure of 1,000 bar, particularly preferably of 800 bar and further preferably of 600 bar not being exceeded in the liquid phase.
- the present invention relates to the use of water, alcohols such as ethanol or butanol, or mixtures of water and ethanol or water and butanol as a splitting agent for splitting compounds of structure I under the pressure and temperature conditions mentioned above.
- the invention further relates to a device for producing (meth) acrylic acid comprising, as components which are connected to one another in a fluid-conducting manner, a (meth) acrylic acid synthesis unit, a quench absorber or condensing device, a distillation device and / or a crystallization device and a (meth) acrylic acid device.
- Oligomer splitting device, the (meth) acrylic acid oligomer splitting device a splitting agent reservoir, a first and a second delivery unit, a mixing device, a heating device, a splitting reactor, which is preferably made of high-alloy steels, in particular nickel-based steels, and at least a first to fifth guide, wherein
- the first conveyor unit has an inlet which contains a composition as defined above, including a (meth) acrylic acid oligomer;
- the splitting agent reservoir is connected to the second delivery unit via a first guide;
- the first and the second conveyor unit are connected to the mixing device via a second and third guide;
- the mixing device is connected to the heating device via a fourth guide;
- the heating device is connected to the gap reactor via a fifth guide.
- fluid-conducting is understood to mean that gases or liquids or their mixtures are led through corresponding lines.
- pipelines, pumps and the like can be used for this.
- All reactor types known to the person skilled in the art which can be operated under the pressure and temperature conditions mentioned at the outset can be used as the gap reactor.
- Preferred heating devices are tube reactors, tube bundle reactors and Taylor reactors.
- oligomer splitting device In a preferred embodiment of the oligomer splitting device according to the invention, at least two selected from the mixing device, heating device and the splitting reactor form a spatial unit. It is further preferred that the mixing device, heating device and the splitting reactor form a spatial unit.
- a spatial unit means that, for example, the mixing and heating device are present together in one section and the mixing and heating step takes place at the same location. It is particularly preferred that the heating device and the splitting reactor are present together in one section.
- a condensing device is connected to the splitting reactor via a sixth guide.
- the (meth) acrylic acid is separated from the heavier-boiling impurities.
- the condensing device is operated at a lower pressure than the cracking reactor.
- the crude product formed in the cracking reactor is preferably expanded in the condensing device. This is preferably done in the presence of a protective gas such as nitrogen or argon.
- the separation of the liquid Phase from the gaseous phase can be carried out by separation devices known to the person skilled in the art, such as a cyclone.
- the liquid phase, which still contains large amounts of (meth) acrylic acid oligomers, can be carried out renewed compression can be fed back to the splitting device.
- the gaseous phase which in addition to monomeric (Mefh) acrylic acid can also contain small amounts of (meth) acrylic acid oligomers, can then be fed to the condenser or another purification device, for example a distillation column, for further purification.
- the heavy-boiling impurities separated off in the condensing device can be fed back to the first conveyor unit. This is preferably done if the oligomers are not completely cleaved. On the other hand, no recycle is preferred for high boilers not containing monomers.
- the (meth) acrylic acid separated off via the condensing device if this is accompanied by water, is sent to a crystallization for further purification.
- a device for the production of (meth) acrylic acid preferably has the following structure in the area which has a (meth) acrylic acid synthesis unit and a quench absorber in the synthesis of acrylic acid: propylene and optionally further inert gases such as nitrogen or combustion gases such as CO 2 or nitrogen oxides are fed in a first reactor for a first catalytic oxidation via an educt feed which leads into a first reactor.
- the first reactor is connected via a further line to a second reactor into which the product of the first catalytic oxidation from the first reactor is introduced for a second catalytic oxidation.
- the product of the second catalytic oxidation containing acrylic acid is fed to the lower half of the quench absorber via a line located between the second reactor and the quench absorber.
- the product of the second catalytic oxidation is brought into contact with water in the quench absorber, the water being fed into the quench absorber above the feed of the product of the second catalytic oxidation.
- the first phase can at least partially again be returned to the quench absorber.
- the first phase which is not returned to the quench absorber, is fed to the distillation device in order, for example, to be subjected to an azeotropic separation in which the acrylic acid is concentrated and purified. It is also conceivable that the first phase not returned to the quench absorber is fed to the crystallization device, in which the acrylic acid can also be cleaned. It is also possible that the first phase not returned to the quench absorber is first fed to a distillation device and the acrylic acid purified and concentrated by the distillation device is then fed to the crystallization device. Above the return of the first phase and below the feed of water into the quench absorber, a second phase containing acrylic acid and water can be removed from the quench absorber.
- the second phase can be fed to the distillation device or the crystallization device in the same way as the first phase.
- the exhaust gases derived from the quench absorber can be fed to a catalytic combustion.
- the combustion gases of the catalytic combustion can be fed into the first reactor as inert gases.
- the water recovered from the concentration of acrylic acid can be returned to the quench absorber. Further details on the production of acrylic acid are disclosed in DE 197 40 252 AI, the content of which is hereby incorporated by reference as part of this disclosure.
- a device for producing methacrylic acid has the (meth) acrylic acid synthesis unit and a quench absorber in the synthesis of methacrylic acid by catalytic gas phase oxidation of C 4 starting compounds with oxygen.
- Methacrylic acid is particularly preferably obtainable by catalytic gas phase oxidation of isobutene, isobutane, tert-butanol, isobutyraldehyde, methacrolein or methyl tert-butyl ether. Further details are disclosed in EP 0 092 097 B1, EP 0 058 927 and EP 0 608 838, the content of which is hereby incorporated by reference as part of this disclosure.
- the composition which is fed to the first conveyor unit corresponds to the composition which is obtained as the bottom product of the distillative workup of the (meth) acrylic acid solution.
- the composition which is fed to the first conveyor unit corresponds to the composition which is obtained as mother liquor in the purification of the distillate by crystallization.
- the invention further relates to the use of the device described above for the production of (meth) acrylic acid.
- the invention also relates to the use of (meth) acrylic acid, obtainable by using the device described above, for the production of fibers, moldings, films, foams, leather and paper auxiliaries, detergents and superabsorbent polymers or hygiene articles.
- FIG. 1 shows a schematic representation of an oligomer splitting device according to the invention.
- FIG. 2 shows the schematic structure of an oligomer splitting device used in the examples according to the invention.
- Fig. 3 shows a schematic representation of a particular embodiment of the oligomer splitting device according to the invention
- the composition containing (meth) acrylic acid oligomers contained in an educt tank 1 according to FIG. 1 is fed via an educt line 2, regulated by an educt valve 3, to an educt pressure pump 4 as the first delivery unit.
- the (meth) acrylic acid oligomer-containing composition is compressed by the educt pressure pump 4 and fed to a mixing device 5. If no additional splitting agent is used, the mixing device can be dispensed with.
- the splitting agent located in a splitting agent reservoir 6 is fed to a splitting agent pressure pump 9 in a controlled manner via a splitting agent line 7 through a splitting agent valve 8.
- the gap medium pressure pump 9 compresses the gap medium as a second delivery unit and feeds it to the mixing device 5.
- the mixture obtained from starting material and splitting agent in the mixing device 5 is fed to a heating device 10 having a splitting reactor.
- the heating device 10 is heated via a heat exchanger 11.
- the fission reactor product of the (meth) acrylic acid oligomer fission located in the heating device 10 is expanded via a relief valve 12 and fed to a condenser 13.
- Protective gas is supplied to the condenser 13 via a protective gas supply 14.
- the condenser 13 is cooled via a coolant supply 15 and a coolant discharge line 16, so that high boilers are concentrated in the lower region of the condenser 13 and, in a condenser head 17, (meth) acrylic acid is optionally enriched with water, which is fed via a pure product line 18 to a crystallization device 19 , in which the (meth) acrylic acid is separated from the adhering water and further purified.
- the crystallization device 19 can also be a distillation or condensation device.
- high boilers are transferred into a high boiler, which on the one hand can be returned to the feed tank 1 or on the other hand can be fed to a high boiler removal 22.
- FIG. 2 shows the experimental setup used in the following examples. With regard to the individual parts of the oligomer splitting device, reference is made to the statements relating to FIG. 1.
- FIG. 3 shows a special embodiment of the splitting device according to the invention, in which the expansion of the splitting product is not carried out in the condenser 13, as shown in FIG. 1, but in an expansion device 23 (flash device) which is separate from the condenser.
- a liquid phase P1 and a gaseous phase P2 are obtained in the flash device 23 (see FIG. 3).
- the gaseous phase P2 which may also contain small amounts of oligomers in addition to monomeric (meth) acrylic acid, can then be introduced into a further purification device 13, which is, for example, an evaporator which is a distillation column, optionally before the introduction a condensation of the components of the gaseous phase P2 can be carried out.
- the liquid phase P1 which still contains large amounts of (meth) acrylic acid oligomers, can be fed to the high boiler removal 22 (25) or can be returned to the heating device 10 for cleavage. If a splitting agent is used for the splitting, the liquid phase P1 can be returned to the heating device via the mixing device 5, as shown in FIG. 3. If no additional splitting agent is added to the composition to be split, the liquid phase P1 can also be fed directly to the heating device 10 (not shown) after appropriate compression.
- FIG. 2 An apparatus shown in FIG. 2 was used, in which two HPLC pumps were used as delivery units and a static mixer from SULZER with the dimensioning 80 15.5 mm in front of the cracking reactor.
- a reactor was used in the Marlotherm bath.
- a spring valve from Hoke as a relief valve
- the pressurized product obtained in the cracking reactor was released and subjected to condensation in a flash dome with an intensive cooler DN50.
- the product collected in the sump of the flash dome was examined for its constituents by means of GC and Karl Fischer titration.
- the degree of cleavage [in%] was determined from the compositions obtained in this way. The degree of cleavage is defined as follows:
- Degree of cleavage 100 x (number of moles of the split dimers / number of moles of the dimers contained in the composition used)
- the (meth) acrylic acid oligomers were used in the form of a composition which was obtained as the bottom product in the working up of an aqueous acrylic acid solution by distillation.
- the compositions are given in the examples below.
- a bottom product obtained in the distillative workup of an aqueous acrylic acid solution containing 0.1% by weight of water, 54% by weight of acrylic acid and 31% by weight of dimeric acrylic acid was split at different temperatures in the device described above.
- the degree of cleavage was determined. The following values were determined for the degree of cleavage:
- a bottom product obtained in the distillative workup of an aqueous acrylic acid solution containing 0.1% by weight of water, 54% by weight of acrylic acid and 31% by weight of dimeric acrylic acid was split in the device described above using different amounts of water. The degree of cleavage was determined.
- the indication -19 indicates that after heating in the splitter under pressure, the amount of dimers increased in the absence of water.
- Table 2 shows that the degree of cleavage increases with the amount of water and the temperature.
- Table 3 shows that the reaction takes place essentially spontaneously and is completed after only three minutes (at 280 ° C.).
- a bottom product obtained in the distillative workup of an aqueous acrylic acid solution containing 0.1% by weight of water, 60% by weight of acrylic acid and 22% by weight of dimeric acrylic acid was cleaved with butanol as the cleaving agent. The degree of cleavage was determined.
- Table 4 shows that the cleavage process according to the invention enables a degree of cleavage of 95% to be achieved within approximately 5 minutes.
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Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102004008575A DE102004008575A1 (en) | 2004-02-19 | 2004-02-19 | Cleavage of oligomeric (meth) acrylic acid in the liquid phase under pressure |
PCT/EP2005/001705 WO2005080308A1 (en) | 2004-02-19 | 2005-02-18 | Cleaving oligomeric (meth)acrylic acid in the liquid phase and under pressure |
Publications (1)
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EP1718592A1 true EP1718592A1 (en) | 2006-11-08 |
Family
ID=34832909
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP05715401A Withdrawn EP1718592A1 (en) | 2004-02-19 | 2005-02-18 | Cleaving oligomeric (meth)acrylic acid in the liquid phase and under pressure |
Country Status (8)
Country | Link |
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US (1) | US20070280866A1 (en) |
EP (1) | EP1718592A1 (en) |
JP (1) | JP2007523120A (en) |
CN (1) | CN1934062A (en) |
BR (1) | BRPI0507845A (en) |
DE (1) | DE102004008575A1 (en) |
WO (1) | WO2005080308A1 (en) |
ZA (1) | ZA200606855B (en) |
Families Citing this family (9)
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DE102004005863A1 (en) * | 2004-02-05 | 2005-09-08 | Stockhausen Gmbh | Reactor with an insert having a heat exchanger area |
DE102006036177B4 (en) * | 2006-07-21 | 2013-05-08 | Evonik Degussa Gmbh | Apparatus and process for the production of acrylic acid with reduced autoxidation tendency |
DE102006039205A1 (en) * | 2006-08-22 | 2008-03-20 | Stockhausen Gmbh | On renewable raw materials based acrylic acid and water-absorbing polymer structures and processes for their preparation by dehydration |
EP2786980A1 (en) * | 2007-08-31 | 2014-10-08 | Arkema Inc. | Method of decarboxylating maleic acid to acrylic acid |
DE102008054587A1 (en) * | 2008-12-12 | 2010-06-17 | Basf Se | Process for the cleavage of Michael adducts contained in a liquid F, which was formed during the production of acrylic acid or its esters |
DE102012212424A1 (en) * | 2012-07-16 | 2014-01-16 | Basf Se | Process for the preparation of acrylic acid by a thermolysis of poly-3-hydroxypropionate catalyzed by at least one molecular active compound |
FR3008971B1 (en) * | 2013-07-29 | 2016-08-19 | Arkema France | PROCESS FOR THE CONTINUOUS PRODUCTION OF LIGHT ACRYLATES BY ESTERIFICATION OF A RAW ESTER ACRYLIC ACID |
DE102013217386A1 (en) | 2013-09-02 | 2015-03-05 | Evonik Industries Ag | Process for the production of acrylic acid |
DE102015215662A1 (en) | 2015-08-18 | 2017-02-23 | Friedrich-Alexander-Universität Erlangen-Nürnberg | Process for the implementation of equilibrium-limited reactions |
Family Cites Families (21)
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US3086046A (en) * | 1959-01-30 | 1963-04-16 | Basf Ag | Cleavage of diacrylic acid to form acrylic acid |
US3868410A (en) * | 1972-08-03 | 1975-02-25 | Celanese Corp | Conversion of oligomeric acrylates to acrylate monomers |
DE2407236C2 (en) * | 1974-02-15 | 1983-02-03 | Hoechst Ag, 6000 Frankfurt | Process for the production of monomeric acrylic acid from residues that arise during the processing of crude acrylic acid |
US4230888A (en) * | 1977-12-15 | 1980-10-28 | Standard Oil Company (Ohio) | Process for purification of acrylic acid by fractional crystallization |
US4317926A (en) * | 1978-01-19 | 1982-03-02 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Process for preparing and recovering acrylic acid |
JPS5498718A (en) * | 1978-01-19 | 1979-08-03 | Nippon Shokubai Kagaku Kogyo Co Ltd | Recovery of acrylic acid |
DE3106557A1 (en) * | 1981-02-21 | 1982-09-16 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING (ALPHA) ALKYLACROLEINS |
DE3213681A1 (en) * | 1982-04-14 | 1983-10-27 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING (ALPHA) ALKYLACROLEINS |
FR2727964B1 (en) * | 1994-12-12 | 1997-01-24 | Atochem Elf Sa | PROCESS FOR RECOVERING THE LIGHT NOBLE PRODUCTS CONTAINED IN THE DISTILLATION RESIDUES FROM THE MANUFACTURING PROCESSES OF ACRYLIC ACID AND ITS ESTERS |
DE19701737A1 (en) * | 1997-01-20 | 1998-07-23 | Basf Ag | Process for the esterification of (meth) acrylic acid with an alkanol |
DE19740252A1 (en) * | 1997-09-12 | 1999-03-18 | Basf Ag | A novel method of acrylic and methacrylic acid production by catalytic gas oxidation of 3 - 4C hydrocarbons |
DE19924533A1 (en) * | 1999-05-28 | 2000-11-30 | Basf Ag | Fractional condensation of acrylic acid-containing oxidation gas with acrylic acid oligomer drawn off and cracked to give acrylic acid which is fed to the quenching liquid circuit |
US6498272B1 (en) * | 1999-03-06 | 2002-12-24 | Basf Aktiengesellschaft | Method for producing acrylic acid |
MY122671A (en) * | 1999-03-06 | 2006-04-29 | Basf Ag | Fractional condensation of a product gas mixture containing acrylic acid |
DE50108001D1 (en) * | 2000-04-11 | 2005-12-15 | Basf Ag | PROCESS FOR CLEANING A CRUDE ACRYLIC MELT |
DE10036880A1 (en) * | 2000-07-28 | 2002-02-07 | Basf Ag | Control of a washing column in a melt crystallization process |
BR122012016827B1 (en) * | 2001-12-04 | 2015-07-14 | Mitsubishi Chem Corp | Method for installing liquid level meter |
JP4318431B2 (en) * | 2002-06-04 | 2009-08-26 | 株式会社日本触媒 | Method for producing (meth) acrylic acid (salt) polymer |
DE10247240A1 (en) * | 2002-10-10 | 2004-04-22 | Basf Ag | Process for the production of acrylic acid |
WO2005007609A1 (en) * | 2003-07-11 | 2005-01-27 | Basf Aktiengesellschaft | Thermal separation method for separating at least one (meth)acrylmonomer-enriched material flow |
DE10332758A1 (en) * | 2003-07-17 | 2004-05-27 | Basf Ag | Thermal separation process for the separation of at least one (meth)acrylic monomer enriched material stream comprises use of a device having separate volume elements and defined residence time |
-
2004
- 2004-02-19 DE DE102004008575A patent/DE102004008575A1/en not_active Withdrawn
-
2005
- 2005-02-18 CN CNA2005800089245A patent/CN1934062A/en active Pending
- 2005-02-18 EP EP05715401A patent/EP1718592A1/en not_active Withdrawn
- 2005-02-18 US US10/589,775 patent/US20070280866A1/en not_active Abandoned
- 2005-02-18 BR BRPI0507845-8A patent/BRPI0507845A/en not_active IP Right Cessation
- 2005-02-18 WO PCT/EP2005/001705 patent/WO2005080308A1/en active Application Filing
- 2005-02-18 JP JP2006553550A patent/JP2007523120A/en active Pending
-
2006
- 2006-08-17 ZA ZA200606855A patent/ZA200606855B/en unknown
Non-Patent Citations (1)
Title |
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See references of WO2005080308A1 * |
Also Published As
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BRPI0507845A (en) | 2007-07-10 |
DE102004008575A1 (en) | 2005-09-08 |
JP2007523120A (en) | 2007-08-16 |
CN1934062A (en) | 2007-03-21 |
WO2005080308A1 (en) | 2005-09-01 |
US20070280866A1 (en) | 2007-12-06 |
ZA200606855B (en) | 2008-07-30 |
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