TWI574943B - Process for preparation of methacrylic acid and methacrylic acid esters - Google Patents

Description

Method for preparing methacrylic acid and methacrylic acid esters

The present invention relates to a process for the preparation of methacrylic acid, a process for the preparation of methacrylates and a process for the treatment of an aqueous phase comprising at least one organic compound.

Methacrylic acid (MAA) and methacrylates such as methyl methacrylate (MMA) and butyl methacrylate are used in a wide variety of applications. The commercial production of methacrylic acid occurs, inter alia, by a heterogeneously catalyzed gas phase oxidation reaction of isobutylene, tert-butanol, methacrolein or isobutyraldehyde. The gaseous reaction phase thus obtained is converted to an aqueous solution of methacrylic acid by cooling and condensation, optionally separated from low boiling materials such as acetaldehyde, acetone, acetic acid, acrolein and methacrolein and subsequently introduced into a solvent extraction column.俾 Extract and separate methacrylic acid using a suitable extractant such as a short chain hydrocarbon. The separated methacrylic acid is further purified, for example, by distillation, and high boiling impurities such as benzoic acid, maleic acid, and terephthalic acid are separated to obtain pure methacrylic acid. This known method is described, for example, in EP 0 710 643, US 4,618, 709, US 4, 956, 493, EP 386 117 and US 5,248,819.

These known processes produce large amounts of wastewater at various stages of the process, the largest of which is in the form of an aqueous phase remaining after the methacrylic acid is extracted from the quenching phase. The water mainly comes from the steam or water added to the gas phase oxidation step, and the water as a quenching agent in the cooling and condensation steps and the oxidation reaction itself. water. This wastewater contains a significant amount of organic compound and can no longer be used or disposed of safely without further treatment to remove at least a portion of the organic compounds. Such organic compounds typically include undesired products (such as methacrylic acid due to incomplete extraction into the organic extractant) and other by-products of the oxidation step, such as acrylic acid, acetic acid, and propionic acid, which are also of commercial value. The organic content in this wastewater is usually too high to be incompatible with water treatment methods (such as biological treatments, such as activated sludge methods) that do not require significant dilution, considerable time, and very large treatment facilities, such that they are often burned at Waste water in the commercial manufacture of methacrylic acid, as described, for example, in US 4,618,709. However, the combustion of wastewater is not conducive to the environment and economy, requires the input of high energy, leads to radiation that may require further treatment before being released to the environment, and also results in the loss of potentially valuable organic compounds present in the wastewater and the loss of water itself. .

It may therefore be advantageous to be able to recover at least a portion of the organic compounds present in the wastewater. It may also be advantageous to recover at least some of the water itself, having a low organic content sufficient to allow it to be biologically treated and/or arbitrarily discharged to the environment without further treatment, or having a purity sufficient to render the water reusable. For example, as industrial process water or in the reaction itself, for example in an oxidation and/or quenching step. CN 1903738 proposes the use of a membrane separator and subsequent purification of waste water from acrylic acid production in a rectification column and recovery of acrylic acid, toluene and acetic acid. A disadvantage of membrane filtration is that it usually requires a large amount of water (often using the wastewater itself) to wash away components that do not pass through the filter. This cleaning water itself with an increased concentration of organic compounds must then be further processed or burned.

The object of the invention is to generally overcome the disadvantages of the prior art methods as much as possible.

A further object is to increase the overall efficiency and/or yield of the methacrylic acid manufacturing process by recovering organic compounds from the process wastewater.

Another object of the present invention is to minimize the contamination of wastewater with organic compounds, to make the water reusable, to carry out biological purification processes, or to arbitrarily discharge to the environment after biological or other types of purification methods, rather than with organic compounds. combustion.

The contribution to the above object is achieved by a process for preparing at least one of methacrylic acid and methacrylic acid ester, which comprises the following process steps: a1) gas phase oxidation of at least one C ₄ compound to obtain methacrylic acid. a reaction phase; a2) quenching the reaction phase to obtain a crude aqueous phase comprising methacrylic acid; a3) extracting at least a portion of methacrylic acid from the crude aqueous phase containing methacrylic acid to an organic solvent to obtain a methyl group a crude organic phase of acrylic acid and a first aqueous phase, wherein the first aqueous phase comprises the following components: i. at least 65% by weight, based on the total weight of the first aqueous phase, preferably from 65% to 99.9% by weight In the range, more preferably from 70% by weight to 99.8% by weight, still more preferably from 75% by weight to 99% by weight, more preferably from 76% by weight to 98.5% by weight. More preferably, it is in the range of from 77% by weight to 98% by weight, even more preferably in the range of from 78% by weight to 97.5% by weight, even more preferably in the range of from 79% by weight to 95% by weight, and more preferably Preferably, the water is in the range of from 80% by weight to 90% by weight, and ii. The total weight of the aqueous phase is not more than 35% by weight, preferably from 0.1% by weight to 35% by weight, preferably from 0.2% by weight to 30% by weight, more preferably from 1% by weight. More preferably in the range of from 1.5% by weight to 24% by weight, still more preferably in the range of from 2% by weight to 23% by weight, even more preferably from 2.5% by weight to 22% by weight In the range of % by weight, even more preferably in the range from 5% by weight to 21% by weight, more preferably from 10% by weight to 20% by weight, in addition to at least one organic compound (except in method step a3) In addition to the organic solvent used as the extractant, wherein the sum of the weights of i. and ii. is 100% by weight; a4) separating at least a portion of the methacrylic acid from the crude organic phase obtained in process step a3) and optionally purifying ; a5) optionally esterifying at least a portion of the methacrylic acid obtained in step a4); b) extracting at least a portion (preferably all) of the first aqueous phase obtained in step a3) with an extractant, Forming an extract phase comprising component ii. and a second aqueous phase, the component of the second aqueous phase being consumed compared to the first aqueous phase ;c) at least partially separating the second aqueous phase obtained in step b) from the extract phase obtained in step b); d) optionally at least partially separating at least a portion of the second aqueous phase obtained in step c) An organic compound, obtaining a third aqueous phase, wherein at least one organic compound in the third aqueous phase is depleted compared to the second aqueous phase; e) optionally separating at least a portion of the extractant from the extracting phase to obtain at least one Extract of component ii.

One solution to the above object is also achieved by a process for treating an aqueous phase comprising at least one organic compound comprising the following process steps: a) providing a first aqueous phase comprising the following components: i. total weight of the first aqueous phase At least 65% by weight, preferably from 65% by weight to 99.9% by weight, more preferably from 70% by weight to 99.8% by weight, still more preferably from 75% by weight to 99% by weight More preferably, it is in the range of from 76% by weight to 98.5% by weight, more preferably from 77% by weight to 98% by weight, even more preferably from 78% by weight to 97.5% by weight. Within, even more preferably from 79% by weight to 95% by weight, still more preferably from 80% by weight to 90% by weight Water in the range of ii. and not more than 35% by weight, preferably from 0.1% by weight to 35% by weight, based on the total weight of the first aqueous phase, preferably from 0.2% by weight to 30% by weight More preferably, it is in the range of from 1% by weight to 25% by weight, still more preferably in the range of from 1.5% by weight to 24% by weight, more preferably from 2% by weight to 23% by weight. Even more preferably in the range of from 2.5% by weight to 22% by weight, even more preferably in the range of from 5% by weight to 21% by weight, still more preferably in the range of from 10% by weight to 20% by weight An organic compound wherein the sum of the weights of i. and ii. is 100% by weight, b) extracting at least a portion (preferably all) of the first aqueous phase with an extractant to form at least one component ii. and second The extract phase of the aqueous phase, at least one component of the second aqueous phase is depleted compared to the first aqueous phase; c) at least partially separating the second aqueous phase from the extract phase; d) optionally from step c The second aqueous phase obtained at least partially separates at least one organic compound to obtain a third aqueous phase, at least one of the third aqueous phase compared to the second aqueous phase Organic compound is depleted; E) optionally separated from the extract phase at least a portion of the extraction agent, a composition comprising at least one component ii extract.

C for gas phase oxidation reaction of a1) in accordance with step ₄ of the method of the present invention is preferably a compound selected from isobutylene, tert-butanol, methacrolein or isobutyraldehyde, and two or more C ₄ compounds mixtures thereof. In a preferred aspect of the present invention, C ₄ compound is derived from methyl tertiary butyl ether cleavage (MTBE) or ethyl tertiary butyl ether (ETBE) is.

The gas phase oxidation reaction in step a1) of the process according to the invention preferably takes place in the presence of at least one oxidation catalyst. If the C ₄ compound is isobutylene or tert-butanol, a gas phase oxidation reaction for obtaining a gas phase comprising methacrylic acid can occur in one step, whereby a step in the present context is considered to mean preliminary oxidation to isobutylene. The aldehyde and further oxidation to methacrylic acid occur substantially in the same reaction zone in the presence of at least one catalyst. Alternatively, the gas phase oxidation reaction in step a1) may occur in more than one step, preferably two steps, preferably two or more reaction zones separated from each other, thereby A plurality of catalysts are preferred, and each catalyst is preferably present in a separate reaction zone with each of the other catalysts. In the two-step gas phase oxidation, the first step of C ₄ compound is preferably at least partial oxidation of methacrolein, followed by at least partial oxidation of methacrolein to methacrylic acid. Accordingly, for example, preferably at least one catalyst suitable for the oxidation of at least one C ₄ compound to methacrolein is present in the first reaction step and at least one catalyst suitable for the oxidation of methacrolein to methacrylic acid is present in the second reaction. In the steps.

The reaction conditions suitable for gas phase catalytic oxidation are, for example, from about 250 ° C to about 450 ° C, preferably from about 250 ° C to about 390 ° C and from about 1 atmosphere to about 5 atm. The change in space velocity may range from about 100 to about 6000 (NTP) per hour, and preferably from about 500 to about 3000 per hour. C ₄ feed (such as isobutylene) oxide (e.g., vapor phase catalytic oxidation) to methacrolein and / or methacrylic acid, and the catalyst system for this example, from US 5,248,819, US 5,231,226, US 5,276,178 , US 6,596,901, US 4,652,673 It is well known in the literature of US 6,498,270, US 5,198,579, US 5,583,084.

Particularly preferred catalysts and processes suitable for the oxidation of isobutylene or tert-butanol to methacrolein and/or methacrylic acid are described in EP 0 267 556, and are particularly preferred catalysts for the oxidation of methacrolein to methacrylic acid. And methods are described in EP 0 376 117. The documents are hereby incorporated by reference in their entirety for all purposes in the extent of the disclosure.

In the process according to the invention, the gas phase oxidation of methacrolein to methacrylic acid preferably occurs at a temperature of from about 250 to less than about 350 ° C, at a pressure of from about 1 to about 3 atm and At a volumetric load of from about 800 to about 1800 Nl/l/h.

Oxygen is typically used as the oxidant, for example in the form of air, or in the form of oxygen, or in the form of oxygen diluted with at least one gas inert under the reaction conditions, such as at least one of nitrogen, carbon monoxide and carbon dioxide, whereby air is used as the oxidant. Preferably, nitrogen and/or carbon dioxide is used as the diluent gas. If carbon dioxide is used as the diluent gas, it is preferably carbon dioxide recycled from combustion, preferably catalytic or thermal combustion of the reaction gas and/or by-products. The gas which carries out the gas phase oxidation reaction in step a1) of the process according to the invention preferably also comprises water, which is usually present in the form of water vapour. Oxygen, and an inert gas or gases such as water vapor may be introduced before, during or prior to the reaction or during the reaction phase and the C ₄ compound or composition.

In a preferred embodiment of the process according to the invention, at least one C ₄ compound, air or oxygen and recycled oxidation reactor outlet gas (preferably an oxidation reactor outlet gas which has been combusted prior to the cycle) will be included. The mixture is supplied to step a1). Reactor off-gas separation system depends on the conditions and the presence and action of a combustion step preferably comprises C ₄ and at least one compound of the unreacted at least one carbon oxide, nitrogen and oxygen, and water.

In the two-step gas phase oxidation reaction according to the present invention, the preferred volume ratio of the C ₄ compound:O ₂ :H ₂ O:inert gas in the first step is usually 1:0.5-5:1-20: 3-30, preferably 1:1-3:2-10:7-20. The amount of methacrolein: O ₂ :H ₂ O: inert gas in the second step is preferably from 1:1 to 5:2 to 20:3 to 30, preferably from 1:1 to 4:3 to 10: 7-18.

In step a2) of the process according to the invention, the gas phase comprising methacrylic acid is cooled and condensed (often known as quenching) to obtain a condensate in the form of a crude aqueous solution comprising methacrylic acid. Condensation can occur by any means known and apparently suitable to those skilled in the art, for example by cooling a gas phase comprising methacrylic acid to at least one of its components (particularly at least water and methacrylic acid). One) the temperature of the dew point. Suitable cooling methods are known to those skilled in the art, for example by cooling with at least one heat exchanger, or by quenching, for example by spraying a liquid phase, for example with water, an aqueous composition or an organic solvent, such as selected from aromatics. Or an organic solvent of a mixture of aliphatic hydrocarbons or at least two of them, whereby the preferred organic solvent has a relatively low vapor pressure under quenching conditions, such as heptane, toluene or xylene, thereby using water as The quench liquid according to the present invention is preferably, and at least a portion of the condensate formed by the quenching step itself is even more preferred. Suitable quenching methods are known to those skilled in the art, for example from DE 21 36 396, EP 297 445, EP 297 788, JP 01193240, JP 01242547, JP 01006233, US 2001/0007043, US 6,596,901, US 4,956,493, US 4,618,709. The disclosure of such quenched acrylic and methacrylic materials is hereby incorporated by reference and constitutes a part of the present disclosure. It is preferred according to the invention to cool the gas phase to a temperature between 40 and 80 ° C and to wash with water and/or condensate from the quenching step to obtain an aqueous solution comprising methacrylic acid, which may also comprise different Contents of impurities such as acetic acid, maleic acid, fumaric acid, citraconic acid, acrylic acid and formic acid, and aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, acrolein, methacrolein, ketones and The C ₄ compound or compound of the reaction. The impurities and water must be separated from the methacrylic acid to the greatest extent possible to obtain high purity methacrylic acid.

Extraction of at least a portion of the methacrylic acid from the crude aqueous solution comprising methacrylic acid occurs in process step a3) using, for example, at least one organic solvent, preferably at least one organic solvent which is substantially immiscible with water, This makes it possible to form an aqueous phase and an organic phase. Process step a3) also comprises separating the aqueous phase and the organic phase from each other. Preferred organic solvents which can be used in step c) of the process according to the invention have a boiling point which is different (preferably lower) from the boiling point of methacrylic acid. In the process according to the invention, the organic extractant used in process step a3) preferably has a boiling point measured at atmospheric pressure and below 161 °C. The organic extractant can in principle be separated from the methacrylic acid by, for example, distillation (preferably partial distillation), preferably to the extent of the step a4) of the process according to the invention, preferably in a distillation apparatus. The layer higher than pure methacrylic acid is at least partially removed as an extractant of low boiling. The separated organic extractant or a portion thereof can be directed back to process step a3), optionally after at least one cooling and/or purification step. Preferred organic solvents for this step are particularly selected from the group consisting of alkanes and aromatics (preferably alkyl aromatics), hydrocarbons, and thus preferably at least one organic solvent selected from the group consisting of C ₆ -C ₈ hydrocarbons, whereby It is particularly preferred as heptane, toluene and xylene, and heptane (preferably n-heptane). Process step a3) can be carried out in any manner known and apparently suitable to the skilled person, preferably in reverse flow extraction, for example using a solvent extraction column, a pulsating packed column or a packed column, a rotary extractor, a washing column, phase separation Or other device suitable for extracting the aqueous phase with an organic solvent and separating the organic phase from the aqueous phase. It is preferred according to the invention to comprise at least a portion, preferably at least 50% by weight, preferably at least about 70% by weight, preferably at least about 80% by weight, more preferably at least about 90% by weight, in the methyl group. The methacrylic acid in the aqueous acrylic acid solution is extracted into the organic phase.

In step a3) of the process according to the invention, therefore, two phases are obtained: a crude organic phase comprising methacrylic acid, which is guided to step a4) of the process according to the invention, and a component comprising the amounts described above. The first aqueous phase of i. and ii. (water and at least one organic compound). The organic compound in the first aqueous phase which may comprise component ii. is any organic compound formed during the gas phase oxidation reaction, such as those described above in connection with the crude aqueous phase obtained in the quenching step, and C ₄ compounds and unreacted remainder of the aqueous phase to remain in any methacrylic acid. Although it is possible to include in the first aqueous phase a small amount of organic solvent for extraction in process step a2), for example due to an organic phase which is not completely separated from the first aqueous phase, this solvent is not considered to be component ii.

In step a4) of the process according to the invention, the crude organic phase comprising methacrylic acid obtained in step a3) is subjected to separation, preferably a thermal separation process, for use as an organic extractant in process step a3) The solvent separates at least a portion of the methacrylic acid contained therein. If thermal separation is used, this is preferably distillation, whereby the organic solvent used for the extraction in process step a3) is preferably removed as an overhead product or in the upper layer of the distillation column, while methacrylic acid or methyl-rich The phase of the acrylic acid is removed as a bottom product or in a distillation column layer that is lower than the extraction solvent. It is also possible to use, for example, a fractionation or rectification column such that impurities having a higher boiling point than methacrylic acid remain in the bottom product and higher purity methacrylic acid can be removed in a layer higher than the bottom of the column. If the organic solvent used for the extraction has a boiling point higher than the boiling point of methacrylic acid, it is also possible to remove the methacrylic acid phase at the top of the column and/or at the higher column layer. Further purification of the methacrylic acid or methacrylic acid rich phase thus obtained may utilize additional thermal methods such as distillation or rectification, or otherwise, such as crystallization. The process according to the invention may also comprise intermediate steps before or during process step a4), such as separation of low boiling or high boiling stripping or distillation, removal of solid impurities by filtration, crystallization, washing and the like. One or more. The number of purification and other separation steps depends on the amount of contamination and the desired purity of the final product of methacrylic acid. If methacrylic acid is used as such (for example, as a monomer or co-monomer) for the preparation of methacrylic acid polymers, higher purity may be preferred, depending on the final application. If you want to esterify methacrylic acid, you can accept a lower purity of A The base acrylic acid, for example, if the ester final product can be purified more simply, more efficiently or more efficiently than methacrylic acid.

The esterification of at least a portion of the methacrylic acid thus obtained in process step a5) can be carried out in any manner known and apparently suitable by the skilled artisan, optionally in the presence of a polymerization inhibitor, to prevent methacrylic acid and/or Polymerization of methyl acrylate. The manner in which esterification is carried out in the step a5) is not particularly limited. The esterification can be carried out, for example, as described in US 6,469,202, JP 1249743, EP 1 254 887, US 4,748,268, US 4, 474, 981, US 4, 956, 493, or US 4, 464, 229, the disclosure of which is hereby incorporated herein incorporated herein And constitute a part of the invention. Esterification in a liquid phase is preferred. If the esterification occurs by direct reaction between methacrylic acid and an alcohol, it is preferred to catalyze the reaction with a suitable catalyst. Esterification catalysts are known to those skilled in the art and include, for example, heterogeneous or homogeneous catalysts such as solid state catalysts or liquid catalysts. The esterification catalyst is preferably an acidic ion exchange resin such as those described in US 6,469,292, JP 1249743, EP 1 254 887 or on the market under the trade names Amberlyst ^® (Rohm and Haas Corp.), Dowex ^® (Dow). Obtained by Corp.) or Lewertit ^® (Lanxess AG), or an acid capable of catalyzing esterification, such as H ₂ SO ₄ sulfate.

The methacrylate prepared in step a5) of the process according to the invention preferably has the formula [CH ₂ =C(CH ₃ )C(=O)O] _n -R and can be supported by methacrylic acid An alcohol of the formula R(OH) _m is esterified to form, whereby n and m represent an integer from 1 to 10, preferably from 1 to 6, more preferably from 1 to 5, still more preferably from 1 to 4. More preferably from 1 to 3, and R is selected from linear or branched, saturated or unsaturated, aliphatic or aromatic, cyclic or linear hydrocarbons and linear or branched containing heteroatoms, saturated or not Saturated, aliphatic or aromatic, cyclic or linear hydrocarbons such as alkyl, hydroxyalkyl, amine alkyl, other nitrogen- and/or oxygen-containing residues, ethylene glycol, glycols, triols a bisphenol, a fatty acid residue, whereby R preferably represents methyl, ethyl, propyl, isopropyl, butyl (especially n-butyl, isobutyl), hydroxyethyl (preferably 2) -hydroxyethyl) and hydroxypropyl, preferably 2-hydroxypropyl or 3-hydroxypropyl), 2-ethylhexyl, isodecyl, cyclohexyl, isodecyl, benzyl, 3,3 , 5-trimethylcyclohexyl, stearyl, dimethylaminoethyl, dimethylaminopropyl, 2-tert-butylaminoethyl, ethyl three Glycol, tetrahydrofuranyl, butyl diethylene glycol, methoxy polyethylene glycol-350, methoxy polyethylene glycol 500, methoxy polyethylene glycol 750, methoxy polyethylene glycol 1000, Methoxy polyethylene glycol 2000, methoxy polyethylene glycol 5000, allyl, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, polyethylene glycol 400, 1, 3-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, ethyl diaminecarboxylate, ethoxylated bisphenol A, ethoxylate with 10 ethylene oxide units bisphenol A, trimethylolpropane, an ethoxylated C ₁₆ -C ₁₈ fatty alcohols (such as having 25 ethylene oxide units), 2-trimethylammonium ethyl.

The methacrylates can also be prepared from methyl methacrylate by other methods known to those skilled in the art, for example by transesterification. In another possible preparation of the hydroxy ester derivative, the methacrylic acid according to the invention may be reacted with a corresponding oxygen-containing ring (for example, an epoxide, in particular ethylene oxide or propylene oxide) in a ring opening reaction. reaction.

Preferred methacrylates are alkyl methacrylates, especially methyl methacrylate, ethyl ester, propyl ester, isopropyl ester, butyl ester, especially methyl methacrylate, n-butyl ester, and different Butyl ester, second butyl ester, especially methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate; hydroxy methacrylate derivative, such as hydroxyethyl methacrylate (preferably A 2-hydroxyethyl acrylate) and hydroxypropyl methacrylate (preferably 2-hydroxypropyl methacrylate or 3-hydroxypropyl methacrylate); and other alkyl methacrylates, such as Ethyl acrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, cyclohexyl methacrylate, isodecyl methacrylate, benzyl methacrylate, methacrylic acid 3,3, 5-trimethylcyclohexyl ester, stearyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, 2-tert-butylaminoethyl methacrylate Ester, triethylene glycol ethyl methacrylate, tetrahydrofuran methacrylate, diethylene glycol butyl methacrylate, methoxy Polyethylene glycol-350 methacrylate, methoxy polyethylene glycol 500 methacrylate, methoxy polyethylene glycol 750 methacrylate, methoxy polyethylene glycol 1000 methacrylate, Methoxy polyethylene glycol 2000 methacrylate, methoxy polyethylene glycol 5000 methacrylate, allyl methacrylate, ethoxylation (optionally having, for example, 25 moles EO) C ₁₆ - C ₁₈ fatty alcohol methacrylate, 2 trimethyl ammonium methacrylate ethyl chloride; ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate Ester, polyethylene glycol 200 dimethacrylate, polyethylene glycol 400 dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, glycerol dimethacrylate, ethyl dimethacrylate dimethacrylate, ethoxylated bisphenol A dimethacrylate, ethoxylation (optional) For example, having 10 EO) bisphenol A dimethacrylate; trimethylolpropane trimethacrylate, whereby methyl methacrylate, methacrylic acid Hydroxyethyl acrylate and methacrylate, particularly preferred ester derivatives.

In step b) of the process according to the process of the invention, at least a portion (preferably all) of the first aqueous phase comprising components i. and ii. is extracted with an extractant to form an extract phase and a second aqueous phase. It is preferred according to the invention to extract at least a portion of at least one component ii. into the extract phase such that at least one component ii. of the second aqueous phase is depleted compared to the first aqueous phase. The extraction preferably occurs at ambient or elevated temperatures, preferably from about 15 ° C to about 70 ° C, preferably from about 20 ° C to about 65 ° C, more preferably from The temperature in the range of from about 30 ° C to about 60 ° C is more preferably from about 40 ° C to about 55 ° C. The extraction is preferably liquid-liquid extraction. The extraction can be carried out in any manner known and apparently suitable to those skilled in the art, for example using an extraction column, a wash column, a phase separator or other means known to those skilled in the art and which are clearly suitable for liquid-liquid extraction. The extractants which have been found to be suitable for process step b) of the process according to the invention are organic solvents, ionic liquids and organic or inorganic oils. The extractant (particularly an organic solvent) suitable for use in process step b) of the process according to the invention preferably has at least one of the following properties, preferably at least two, more preferably at least three, More preferably characterized by all of the properties: i) the average k-value of acetic acid in the system extractant-water as determined at 25 ° C according to the method described herein is in the range from 0.1 to 100, preferably from 0.2 to Within the range of 90, better From 0.3 to 80, more preferably from 0.3 to 70, more preferably from 0.4 to 60; ii) no more than 2260 仟 joules/kg, preferably no more than 2000 焓. Joules/kg, preferably no more than 1500 仟 joules/kg, more preferably no more than 1000 仟 joules/kg, and even more preferably no more than 800 仟 joules/kg; iii) boiling points in the range from 35 to 140 °C Preferably, it is in the range of from 35 to 125 ° C, more preferably in the range of from 40 to 120 ° C, still more preferably in the range of from 40 to 110 ° C; iv) at a temperature of 25 ° C, preferably The solubility in water at a temperature of 35 ° C, more preferably at a temperature of 45 ° C, more preferably at a temperature of 50 ° C, does not exceed 150 g / liter, preferably does not exceed 130 g / liter, more preferably does not exceed 110 grams / liter, and more preferably no more than 100 grams / liter, and even better than 90 grams / liter.

The above properties are measured at about 50 ° C and ambient pressure unless otherwise stated. The term 〝k-value 〞 refers to the partition coefficient, that is, the distribution ratio of the respective organic compounds of the component ii. of the present invention to the equilibrium between the organic phase (extraction) and the aqueous phase. A k-value greater than 1 means that more individual organic compounds are present in the organic (extracted) phase than in the aqueous phase. Although the method according to the invention may have a good effect I using an extractant having a k-value of less than 1, it is preferably a higher k-value, such as a k-value greater than 1, since the equivalent is indicated from the first The aqueous phase extracts the organic compound more completely into the extract phase. Although the k-value may be at most 100, it has at most about 5, 10, 20, 30, according to the present invention. An extractant having a k-value of 40, 50, 60, 70, 80 or 90 may also be preferred. It is also acceptable, for example, to have a lower (particularly below 5) and a k-value within the above range, especially if the extractant also has one or more of the other preferred properties within the advantageous range. If the extractant is an organic solvent, the evaporation enthalpy and boiling point are preferably within as low practical limits as possible, in particular the extractant is preferably liquid at the temperature at which the extraction takes place. The evaporation enthalpy is preferably not less than about 22 Torr/mole, and the boiling point is preferably greater than 0 ° C and more preferably not lower than the operating temperature at which the extraction is carried out. The evaporating enthalpy preferably does not exceed the evaporation of water 焓 2260 仟 joules/kg or 40.65 仟 joules/mole, as far as possible to minimize the separation of the second aqueous phase from the extract phase in step c) of the process according to the invention. The energy input necessary for the thermal separation of any residual extractant in the second aqueous phase. The evaporating enthalpy preferably also does not exceed the evaporation enthalpy of at least one of the organic compounds of component ii. to minimize the energy input necessary to thermally separate the extractant from one or more organic compounds of component ii. It is especially preferred that the evaporation enthalpy does not exceed the evaporation enthalpy of at least one of methacrylic acid, acrylic acid and acetic acid. For the same reason and to facilitate separation of the extractant, the boiling point of the extractant is preferably lower than the boiling point of at least one of the organic compounds of component ii., preferably at least one of methacrylic acid, acrylic acid and acetic acid. The boiling point is low and is preferably within the preferred range as low as possible. If an ionic liquid or an organic or inorganic oil is used as the extractant, it is preferred to have as high a vaporization enthalpy and a boiling point as possible, preferably higher than at least one of water and at least one organic compound of component ii. The extractant preferably has only low solubility in water, especially at the extraction temperature, and is preferably substantially or completely insoluble in water, and preferably substantially or completely immiscible with water, so as to be as Completely The extract phase and the second aqueous phase are separated.

In step c) of the process according to the invention, the second aqueous phase is at least partially separated from the extract phase. The extraction according to step b) of the process according to the invention and the separation of process step c) can be carried out in any manner known to the skilled person and apparently suitable, preferably by countercurrent extraction, whereby process steps b) and c are carried out. ) preferably in the same apparatus, for example using an extraction column, a pulsating packed column or packing column, a rotary extractor (especially those using centrifugal force separation), a washing column, a phase separator or a suitable self-aqueous phase Other means of separating the organic phase or the ionic liquid phase. If an organic solvent is used as the extractant in process step b), it is possible to incinerate the extract phase obtained after the separation of process step c). This incineration has the advantage of allowing the substantial organic extract phase to act as a fuel, thus reducing the need to purchase fuel. This choice may be preferred, for example, if unfavorable fuel costs or related requirements, such as ease of transport and/or cost, and/or low market value of one or more of the organic compounds of component ii. Compare the overall effort and expenditure necessary for its separation and/or purification.

The second aqueous phase preferably comprises not more than 5.0% by weight, preferably not more than 4.5% by weight, more preferably not more than 4.0% by weight, still more preferably not more than 3.5% by weight, based on the total weight of the second aqueous phase. More preferably, it is no more than 3.0% by weight, even more preferably not more than 2.5% by weight of the organic compound (except for the extractant used in process step b). The amount of the organic compound other than the extracting agent in the second aqueous phase is preferably as small as possible, and is preferably 0% by weight, although the lower limit of 0.5% by weight, 0.8% by weight, 1.0% by weight or 1.2% by weight is acceptable. In the total amount of organic compound not comprising any residual extractant from process step b) in the second aqueous phase, formaldehyde may generally be present in an amount of up to about 1.5% by weight based on the total weight of the second aqueous phase, with the remainder remaining It consists of C ₂ or higher C-chain organic compounds, in particular C ₂ -C ₆ or C ₂ -C ₄ compounds. The total amount of such organic compounds depends on the number of extraction steps or extraction cycles contained in the extraction of process step b) and the amount of extraction used in the extraction. The more extraction steps result in less organic compound content in the second aqueous phase, but generally also requires longer and/or multi-stage extraction, and/or more extraction dose, which may result in subsequent further processing or incineration. The larger volume of the extract phase.

The process according to the invention may also comprise intermediate steps such as stripping of low boiling or removal of low or high boiling distillation.

In a selection step d) of the process according to the invention, at least one organic compound is at least partially separated from the second aqueous phase to obtain a third aqueous phase, at least one organic compound in the third aqueous phase compared to the second aqueous phase Exhausted. The third aqueous phase preferably comprises no more than 3% by weight, preferably no more than 2.8% by weight, more preferably no more than 2.5% by weight, even more preferably no more than 2.2% by weight, based on the total weight of the third aqueous phase. More preferably, it is no more than 2.0% by weight of the organic compound (except for the extractant used in process step b). The amount of the organic compound in the third aqueous phase is preferably as small as possible and preferably 0% by weight. If the organic compound is present in the third aqueous phase, up to about 1.5% by weight may be in the form of formaldehyde, while the remainder comprises C ₂ or higher C-chain compound (except for the extractant used in process step b) Other than), especially C ₂ -C ₆ or C ₂ -C ₄ compounds. The third aqueous phase thus preferably comprises less than 5000 ppm, preferably less than 4000 ppm, more preferably less than 3000 ppm, preferably from 0 to 3000 ppm, based on the total weight of the third aqueous phase. Preferably, in the range from 0 to 2500 ppm, more preferably from 0 to 2200 ppm, optimally no more than 2000 ppm of organic compounds (except for the C ₁ compound (formaldehyde) and method step b) In addition to the extractant used, the lower limit of 500 ppm or 1000 ppm or 1500 ppm or 1800 ppm may thus be accepted depending on the intended use and/or treatment of the third aqueous phase. The separation in process step d) is preferably thermal separation, such as distillation or azeotropic distillation, preferably at atmospheric pressure. Preference is given to separating the residual extractant from process step b) remaining in the second aqueous phase in the process step d) to the greatest extent possible. If the extractant used in process step b) forms an azeotrope with water, the separation may comprise azeotropic distillation, for example azeotropic distillation using an azeotropic additive. In a preferred embodiment of step d) of the process according to the invention, if distillation separation (particularly by fractionation or rectification) is used in process step d), it is preferred to have a low boiling component (especially having a boiling point) The component lower than the extractant is separated at the top of the column, and the extractant is discharged at the side outlet of the column and any component ii. is discharged with the extractant or at the other side of the column, preferably in the ratio of the extractant. The side outlet is a low side outlet. Any thus separated extractant can then be recycled to the extraction of step b) of the process according to the invention, corresponding to step h) of the process according to the invention. If one or more organic compounds of component ii are separated in the same phase as any of the extractants separated in this step, this phase can be added to the extract phase separated in process step c). If one or more organic compounds of component ii are separated in a different phase than the extractant, this different phase can be directed to step f) or step j) of the process according to the invention. When an organic solvent has been used as the extractant in step b) of the process of the invention, step d) of the process according to the invention is preferably carried out, but if ionic liquid or oil is used in process step b) , you can also perform this step d).

In step e) of the process according to the invention, the extractant used in process step b) is at least partially separated from the extract phase to obtain an extract comprising at least one component ii. If an organic solvent is used as the extractant, the separation in process step e) preferably takes place using a thermal separation process. Suitable thermal separation methods are known to those skilled in the art, and thus distillation, fractionation, rectification, and the like are preferred in accordance with the present invention, whereby vacuum distillation is preferred. One or more separation methods can be included in step e) of the method according to the invention. In a preferred thermal separation process, the organic solvent used herein as the extractant in process step b) has a lower boiling point than the one or more components ii to be separated, the extractant being at the top of the distillation column or at the fractionation column. Or the upper or upper layer of the rectification column is removed, preferably in the upper half of the column, and one or more components ii. or the extract comprising at least one component ii. is in the lower layer, and the extractant is removed in the lower layer. The lower layer or the bottom of the column is removed. The use of an organic solvent having a boiling point lower than at least one component ii. as an extractant in process step b) has the advantage that some or all of the components ii. (especially methacrylic acid and acrylic acid) are thermally sensitive and at temperature When increasing, it tends to be dimerized, oligomerized, or polymerized. The heat treatment of such compounds at elevated temperatures therefore typically requires the addition of a polymerization inhibitor. If the low boiling extractant is to be separated and/or if it is separated into a vacuum distillation, the separation can be carried out at a temperature lower than the boiling point of each component ii., reducing the tendency to polymerize and thus also reducing the need for polymerization inhibitors.

If an ionic liquid or an organic or inorganic oil is used as the extractant in process step b), the separation in process step e) preferably takes place by phase separation or evaporation, preferably by evaporation of the volatile components. Or component class.

The process according to the invention may also comprise one or more intermediate steps between any or all of the process steps, such as stripping of low boiling materials or distillation of low or high boiling materials.

In a preferred embodiment of the method according to the invention, the method further comprises the following method steps: f) separating at least a portion of at least one component ii. from the extract.

The separation in process step f) is preferably a thermal separation process, preferably distillation, fractionation or rectification, preferably vacuum distillation, whereby at least a portion of at least one component ii. is separated from the extract. The extract contains, for example, an extractant or other component ii., in addition to at least one component to be separated ii. If more than one component ii. is included in the extract, for example two or more components ii., it is possible to separate only one component ii. or two or more components ii in process step f). . The choice of distillation, fractionation or rectification as a separation mode can be readily determined by those skilled in the art and will depend primarily on the number and amount of other compounds in the extract from which at least one component ii. is to be separated, and The separation of one or more components ii. and the components of the extract which are not intended to be separated, in particular, the boiling point of the other components of the extract is close to the boiling point of at least one component ii. And if more than one component ii. is to be separated, the boiling points of the components to be separated ii. are close to each other. Another consideration is the desired purity of at least one component ii. to be separated. After step f) of the method according to the invention, it may be possible It may be necessary or even further to purify at least one component ii.

In the process according to the invention, it is possible to subject the third aqueous phase to at least one biological purification treatment in a further process step g).

In the context of the present invention, the term "biopurification treatment" is intended to mean the use of one or more biological organisms and/or microorganisms or biological or biochemically active substances (for example substances derived from such organisms or microorganisms) to increase the purity of water. Any treatment, such as by removing contaminants or impurities, is preferably an organic contaminant. The contaminants and impurities removed in this manner are typically organic compounds remaining in the third aqueous phase. Removal is achieved by digesting or decomposing some or all of the organic compounds. The increase in water purity is measured, for example, by reducing contaminants and/or impurities and/or by reducing the biochemical oxygen demand (BOD) or chemical oxygen demand (COD) of the water, preferably to representative wastewater. The level of reuse, for example, depending on the purity achieved, into industrial process water or in the process according to the invention, in particular in one or both of process steps a1) or a2), or in the environment or In the water supply chain. The biological purification treatment is known to those skilled in the art and may be one or more of the so-called activated sludge treatment. Such treatments are known or known to those skilled in the art. The biological purification treatment can be carried out in one or more stages, or can be continuous or discontinuous treatment.

If the third aqueous phase is subjected to at least one biological purification treatment in process step g), the treatment is preferably at least one of an aerobic treatment and an anaerobic treatment. In a specific example having two or more stages of treatment, for example, anaerobic treatment followed by aerobic treatment may be performed first, followed by aerobic treatment followed by anaerobic treatment, or may be carried out, for example, in successive batch reactors. Use anaerobic and / or aerobic treatment.

In a further aspect of the process according to the invention, in a further process step h), at least a portion of the extractant separated by at least one of process steps d) and e) is recycled to process step b).

A portion or substantially all of the extractant separated by one or both of method steps d) and e) can be directed back to process step b), optionally in one or more intermediate steps, such as cooling, purification (eg , by distillation), washing or the like, or stripping of a variety of volatile compounds. This extractant recycle has the advantage of reducing the total amount of extractant in the process, particularly reducing the amount of spent extraction that must be disposed of.

If the separation in step f) of the process according to the process of the invention is thermal separation, it is not possible to separate the components from each other at any time or, for example, in an economically or technically feasible manner, for example if two or more components have very similar Boiling point. This may be a special case if the extract of method step f) comprises a relatively large amount of components, in particular if one or more components ii. have a composition similar to at least one component ii. to be separated in process step f). At the boiling point, it is more difficult to separate only one component ii. in fine-tuning in process step f). It is then possible to separate two or more components ii. in a further method step j) more suitably or practically, which can be more easily achieved here in accordance with the specific separation requirements of the individual components ii. According to this, in one aspect of the process according to the invention, the at least one component ii. obtained in step f) is a mixture of at least two components ii. and in the following additional process steps: From this mixture at least partially separate at least one component ii.

The separation in method step j) of the method according to the invention may comprise a Or a plurality of separation steps, such as thermal separation, chromatographic separation, chemical separation as discussed above in accordance with other separation steps in the method of the invention (e.g., by a preferential reaction of a component ii. The reaction product separated from one or more other components ii. or the reaction product formed by two or more components ii. to form a reaction product which is more easily separated from each other) or any other known or apparently suitable to those skilled in the art. Separation method.

In a preferred embodiment of the process according to the invention, at least one component ii.) of at least one organic compound (preferably in process step j) of component ii. is at least one selected from the group consisting of carboxylic acids, Organic compounds of aldehydes and ketones. Among these, it is preferred according to the invention that at least one component ii.) at least one component ii. (preferably in process step j) is at least partially ii.) acetic acid, acrylic acid, propionic acid and methacrylic acid At least one of them.

If at least one component ii. separated by at least one of method steps e), f) and j) is or comprises methacrylic acid, in a preferred embodiment of the method according to the invention, at least a portion This methacrylic acid phase is added to the crude aqueous phase obtained in process step a2) and/or to the crude organic phase obtained in process step a3). This may be a preferred embodiment, for example if the methacrylic acid separated by one or more of method steps e), f) and j) does not have the desired purity for its end use. For example, if the isolated methacrylic acid has been separated from one or more components having a lower boiling point than methacrylic acid, it may be preferred to add to the crude aqueous phase. For example, if a component other than methacrylic acid has a higher boiling point than methacrylic acid, it may be preferred to add to the crude organic phase because of such higher boiling boiling. The substance can be separated in method step a4). While methacrylic acid may also play a role in the relative proportions of other components (particularly other components ii.), at least one component separated by at least one of method steps e), f) and j) The nature of the other components in ii. has a greater effect on which phase the methacrylic acid containing phase separated by at least one of method steps e), f) and j) is added to. For example, if at least one of the method steps e), f) and j) is separated from methacrylic acid, it comprises, for example, no more than about 5% by weight, preferably no more than about 4% by weight, preferably Not more than about 3% by weight, preferably not more than about 2% by weight, preferably from about 1% by weight to about 2% by weight of impurities or other components ii., preferably incorporated The methacrylic acid is subjected to an optional purification step of method step a4).

In a further aspect of the method according to the invention, at least a part of at least one component ii. separated by at least one of method steps e), f) and j) or obtained in method step a3) At least a portion of the first aqueous phase accepts the following process steps: k) esterification to obtain an ester phase comprising at least one ester.

This step may be preferred if at least one of the individual components ii. is a carboxylic acid. The details of the esterification step are the same as those described above for process step a5) of the process according to the invention. It may be preferred to esterify at least one component ii. separated by at least one of method steps e), f) and j) (not or in addition to obtaining at least one individual component ii. itself), and component ii In comparison to the esters, the esterification may depend, for example, on the purity of the individual components ii. available, the market for each component ii., or further applications. For example, if the first aqueous phase contains only a low proportion of impurities and/or components that are not intended to be separated, for example, Less than about 6% by weight, preferably less than about 5% by weight, preferably less than about 4% by weight, more preferably less than about 3% by weight, based on the total weight of the aqueous phase, of undesired impurities And/or the total amount of impurities of component ii., in particular, for example, impurities which are more easily separated from the ester of each component ii. by self-component ii. itself, the first aqueous phase obtained in process step a3) At least one component included in the ii. esterification may be preferred.

Particularly preferred esters contained in the ester phase according to the invention are based on C ₁ -C ₄ carboxylic acids and C ₁ -C ₄ alcohols, whereby C ₂ -C ₄ carboxylic acids are used as substrates. Esters are preferred. In addition to the methacrylates described in process step a5), particularly preferred esters are methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate. Ester, second butyl acetate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, second butyl acrylate, methyl propionate, propionic acid Among the esters, n-propyl propionate, isopropyl propionate, n-butyl propionate, isobutyl propionate, and second butyl propionate, among these, acetates and acrylates are preferred.

According to the invention it is possible to have the ester phase comprise at least two esters. This may be if at least one component ii separated in at least one of method steps e), f) and j) or at least a portion of the first aqueous phase obtained in method step a3) comprises at least two An example of a component ii. (particularly at least two carboxylic acids) capable of reacting to form an ester. This particular example may be preferred if at least two components which are capable of reacting to form an ester ii. are particularly difficult to separate, for example by heat or other means such as such properties (such as boiling point, solubility in a given solvent and/or The volatility is very close, and the esters can be separated from each other with a lower degree of difficulty.

The process according to the invention may further comprise the following process steps: m) at least partially separating at least one ester from the ester phase; n) optionally purifying at least one ester isolated in process step m).

In addition to the at least one ester, the ester phase may generally comprise a solvent such as water or at least one organic solvent suitable for the esterification reaction or a mixture thereof, and unreacted components ii., and may also contain additional esters or esters. The separation in process step m) can be any separation fraction known to the skilled artisan and apparently suitable for separating the individual esters from the ester phase. Examples of suitable separation means are, for example, thermal separation (such as distillation, fractionation or rectification), separation methods based on solubility of at least one ester compared to other components of the ester phase, solid-liquid separation ( Such as filtering). Purification of at least one ester isolated in process step m) can also be carried out if necessary or desired. The manner of purification depends on the ester and can thus be considered, for example, by thermal means, by chromatography, by washing or by crystallization.

In a preferred embodiment of the process according to the invention, at least a portion of the at least one ester obtained in at least one of process steps k), m) and n) is used as the extractant in process step b).

In a specific example of the method according to the invention, the method further comprises the steps of: aa1) splitting methyl tributyl ether (MTBE) to obtain at least one C ₄ compound and methanol, wherein at least a portion of at least one C ₄ The compound is supplied as a feed to the gas phase oxidation reaction of at least one of process step a1). MTBE is widely used as a raw material for isobutylene and the splitting of MTBE is well known in the art. The splitting of MTBE can occur in any suitable manner known to those skilled in the art. Suitable catalysts and reaction conditions are described for example in EP 1 149 814, WO 04/ 018393, WO 04/052809; Ullmann's Encyclopedia of Industrial Chemistry, 5 th Edition, Vol.A4, p.488; V.Fattore, M.Massi mauri, G.Oriani, G.Paret, Hydrocarbon Processing , August 1981, p.101-106; Ullmann's Encyclopedia of Industrial Chemistry, 5 th Edition, Vol.A16, p.543-550; A.Chauvel, G.Lefebvre, "Petrochemical Processes, Technical and Economic Characteristics", Vol. 1, Éditions Technip, Paris, 1989, p. 213 et seq.; US 5, 336, 841, US 4, 570, 026 and references cited therein. The disclosures of these references are hereby incorporated by reference in their entirety in their entirety in their entirety in the extent of the disclosure.

MTBE split two major products of C ₄ compounds isobutylene and methanol. An additional C ₄ compound, third butanol, may also be included in the split reaction product phase. In one or both of isobutylene and tert-butanol may be supplied as a feed to a process step a1), the feed composition or method step in addition to other C ₄ content from another source the total content of C ₄ compound. Between one or more intermediate separation and / or purification steps may also be interposed at least one C ₄ compound to MTBE splitting process step thus obtained was supplied with a1) a gas phase oxidation reaction, for example at least one C ₄ compound as possible Separation from methanol and removal from the split may adversely affect any by-products of the gas phase oxidation reaction. Isolation and/or purification can be by any means known to the skilled artisan and apparently suitable. Suitable purification and separation methods are described, for example, in EP 1 149 814, WO 04/018393 and WO 04/052809. After separation of the methanol, a compound comprising C ₄ isobutylene phase may then optionally purified and provided as feed to the process step a1 splitting group as the main component). Suitable purification methods are known to those skilled in the art and preferably comprise at least one of distillation, extraction, adsorption, absorption, chromatography or washing, preferably at least one of distillation and extraction, preferably At least one distillation and at least one extraction. In this step can be from C ₄ compound phase separating at least a portion of the unreacted MTBE. The isolated MTBE can be optionally purified and at least partially recycled to the split reaction.

In a preferred embodiment of the process according to the invention, the methanol obtained in process step aa1) is supplied to process step k). In a further aspect of the method according to the invention, the methanol obtained in process step aa1) can be supplied to process step a5). The methanol can be optionally purified, preferably by thermal purification such as distillation, fractionation or rectification, crystallization, extraction, column or washing, more preferably at least one distillation. An example of purified methanol is described in EP 1 254 887.

The invention also relates to a device for making at least one of acrylic acid and methacrylate comprising at least the following components in fluid communication with each other: A1) gas phase oxidation unit, A2) quench unit, A3) first extraction Unit, A4) the first separation unit, A5) a random first esterification unit, B) a second extraction unit.

It should be understood that the term "flow-through" refers to the connection of a unit such that a fluid (which can be at least one of a liquid, a gas, a vapor, a supercritical fluid, or any other fluid) can be directed from one unit to at least one other. Unit. This may be directly communicated or utilized by a tank truck, for example, via a tube or conduit (e.g., made of a material that is resistant to the reagents and conditions at the time, such as stainless steel or glass or any other suitable material known to those skilled in the art). Or arrange indirect communication between the tanks or reservoirs between the units. If the gas is to be directed and the gaseous form of the gas should be maintained, the means for directing the gas is preferably maintained at a higher temperature than the dew point of the gas. If the liquid is to be directed, the means for directing the liquid is preferably maintained at a temperature higher than the solidification and/or precipitation point of the liquid and/or the component present in the liquid. This can be achieved by means of insulation and/or heating of the individual gases or liquids. All reactors, columns, and other device components are preferably made of materials that are resistant to reagents and conditions, such as temperature and pressure conditions, particularly to such acceptance conditions.

The gas phase oxidation unit A1) preferably comprises at least one reactor suitable for carrying out a gas phase reaction, in particular a pressure reactor, preferably at least one multi-tube reactor formed, for example, as a tube and shell reactor, and/or At least one plate reactor and / or at least one fluidized bed reactor, whereby a multi-tube reactor is preferred. Particularly preferred is at least one multi-tube reactor in which the oxidizing catalyst is disposed in at least one of the tubes, wherein the tube is preferably filled or coated (preferably filled) with an oxidizing catalyst. Preferred oxidation catalysts according to the present invention are those The above is described in relation to the method of the present invention. The reactor material should be resistant and preferably inert to the reagents and conditions at the time of the reactor. Suitable reactors are commercially available, for example, from MAN DWE GmbH, Deggendorfer Werft, Germany or from IHI Corporation, Japan, and form part of the general knowledge of those skilled in the art.

In a two-stage gas phase oxidation reaction, the gas phase oxidation unit may comprise at least two reaction zones, each zone comprising an oxidation catalyst. The at least two reaction zones can be at least two reaction zones in a single reactor, or at least two reactors. The oxidizing catalyst in the first reaction zone is preferably an oxidation catalyst for oxidizing at least one C ₄ compound (preferably isobutylene and/or third butanol) to methacrolein, and in the second reaction zone. The oxidizing catalyst is preferably suitable for oxidizing methacrolein to methacrylic acid. Suitable catalysts are those described above in relation to the method according to the invention.

In a preferred aspect of the apparatus of the present invention, at least one feeder for at least one oxidant source (preferably oxygen, preferably air) and at least one feeder and gas for water and/or steam The phase oxidation unit is in fluid communication. If the gas phase oxidation unit comprises at least a first and additional oxidation zone, the apparatus may comprise at least one feeder for each oxidation zone for at least one source of oxidant and at least one feeder for water and/or steam. The apparatus may additionally comprise a feeder for the diluent, such as nitrogen, argon and/or carbon dioxide, preferably nitrogen or carbon dioxide, for example from a catalytic combustion unit (CCU) or a thermal combustion unit (TCU) (preferably according to the present invention) A recycle gas comprising carbon dioxide in the CCU or downstream of the TCU in the inventive device. Each feeder should be made of a material that is resistant to the reagents and conditions at the time (for example, stainless steel or glass). In a preferred design the oxygen, diluent and water is supplied to the C ₄ flow before entering each reactor, such that the pre-formed mixture into the reactor.

Step a1) of the process according to the invention is preferably carried out in a gas phase oxidation unit.

In a preferred embodiment of the apparatus according to the invention, the quench unit A2) is an absorption unit in which the gaseous oxidation phase is condensed and/or absorbed to form a liquid phase. Preferably, the methacrylic acid present in the oxidizing phase leaving the catalytic reaction zone is condensed in the absorption unit to form a solution (preferably an aqueous solution) comprising methacrylic acid as the main oxidation product. Unreacted methacrolein can also be separated in the absorption unit and, if desired, directed back to the gas phase oxidation zone for further reaction. Quench units suitable for use in the apparatus according to the present invention are known to those skilled in the art. Step a2) of the process according to the invention is preferably carried out in an absorption unit.

In a preferred embodiment of the apparatus according to the invention, the quench unit A2) is followed by a first extraction unit A3). The aqueous solution containing methacrylic acid formed in the quenching unit A2) is guided to the first extraction unit A3) where an organic solvent is provided, and methacrylic acid is preferably extracted into the solvent in a large amount. The organic solvent is preferably substantially immiscible with water, thus forming an aqueous phase in which at least a portion of the methacrylic acid is depleted and an organic phase comprising methacrylic acid. Details regarding preferred organic solvents are set forth in the description of method step a3) above. Process step a3) is preferably carried out in the first extraction unit A3). Any extraction unit known to the skilled artisan and apparently suitable for the extraction of methacrylic acid can be considered as the first extraction unit A3).

The device according to the invention comprises a first separation unit A4) downstream of the first extraction unit A3). If the apparatus according to the invention is used for the manufacture of methyl methacrylate, the first separation unit A4) is upstream of the first esterification unit A5), preferably at the first extraction unit A3) with the first esterification Units A5) are in fluid communication. The first separation unit A4) is preferably suitable for separating and preferably purifying methacrylic acid, in particular for separating methacrylic acid from the extractant used in the first extraction unit A3), and preferably also allowing The other components present in the crude organic phase withdrawn from the first extraction unit A3) of the apparatus according to the invention separate methacrylic acid, corresponding to the crude organic phase of process step a3) of the process according to the invention. The first separation unit A4) is preferably a thermal separation unit, preferably comprising a distillation column, a fractionation column, a rectification column and any other known to those skilled in the art and which are apparently suitable for the separation of process step a3) of the process of the invention. At least one of the thermal separation devices. It is possible that the first separation unit A4) contains more than one separation stage.

The optional first purification unit for purifying the methacrylic acid separated in the first separation unit may also be arranged downstream of the first separation unit. The optional first purification unit can be, for example, a thermal purification unit such as a distillation column, a fractionation column, a rectification column or the like, a crystallization unit or any other device known to those skilled in the art and which is obviously suitable for purifying methacrylic acid.

The device according to the invention may further comprise one or more additional components between any or all of said units or components, such as heat or stripping equipment for separating high and/or low boiling components, for solids/ A device for liquid separation, such as at least one filtration and/or centrifugation, and/or a cooling and/or heating unit. In a preferred design, for example, a distillation column for low boiling materials and Optionally, the filter is also arranged downstream of the quench unit and upstream of the extraction unit. In a further preferred aspect of the two-stage gas phase oxidation unit, the quench unit is arranged between two stages.

Unreacted methacrolein may be separated from any of the quench unit, the first extraction unit, the first separation unit, the first purification unit, or any of the above-described more plant components and directed back to the gas phase oxidation unit for further processing reaction.

The first esterification unit A5) may be arranged in the first separation unit A4) or optionally downstream of the first purification unit. The first esterification unit A5) is not particularly limited and may be any unit suitable for forming a methacrylate (preferably methyl methacrylate) from methacrylate. It is preferably suitable for liquid phase esterification. The first esterification unit A5) preferably comprises an esterification catalyst which may be a heterogeneous or homogeneous catalyst such as a solid or liquid catalyst, and preferably an acidic ion exchange resin such as those in US 6,469,292. Acquired in JP 1249743, EP 1 254 887 or marketed under the trade names Amberlyst ^® (Rohm and Haas Corp.), Dowex ^® (Dow Corp.) or Lewertit ^® (Lanxess AG), or capable of catalyzing esterification Acid, such as sulfuric acid H ₂ SO ₄ .

The second purification unit can be arranged downstream of the first esterification unit A5) to purify the methacrylate produced therein. The optional second purification unit can be, for example, a thermal purification unit such as a distillation column, a fractionation column, a rectification column or the like, a crystallization unit or a skilled person known to the skilled artisan and apparently suitable for purifying methacrylates (especially methyl groups). Any other device of methyl acrylate).

The device according to the invention further comprises a second extraction unit B). a second extraction unit B) suitable for at least one portion of at least one organic compound A portion of the water contained in the first aqueous phase obtained in the first extraction unit A3) is separated (particularly for at least one component ii.), as described above, to obtain a second aqueous phase and an organic phase. Process step b) of the process according to the invention is preferably carried out in a second extraction unit B).

In the second extraction unit B), at least a portion of the first aqueous phase is extracted with an extractant to form a second aqueous phase and an extract phase, and preferably also from the extract phase to the maximum extent possible within the technical limits. Dihydrate phase. Thus, at least process step b) of the method according to the invention and preferably also method step c) is preferably carried out in the second extraction unit B), preferably in a continuous manner. The second extraction unit B) preferably comprises at least one extraction column, washing column, phase separator or cooker known to the skilled person and is obviously suitable for liquid-liquid extraction, and preferably also suitable for separating organic from the aqueous phase. a phase or ionic liquid phase, more preferably a continuous extraction and separation of other means, such as at least one extraction column, at least one pulsation packed column and / or packed column, at least one rotary extractor (especially at least one using centrifugal force) A separate rotary extractor), at least one cleaning column, and/or at least one phase separator. The second extraction unit B) is preferably capable of withstanding ambient temperatures and temperatures outside the ambient temperature and operating at such temperatures, in particular at elevated temperatures, in particular at the abovementioned temperatures relating to process steps b) and c).

At least one incinerator or combustion unit may be included in the apparatus according to the invention, for example for incinerating the extract phase obtained in the second extraction unit.

The device according to the invention may further comprise a third separation unit D). The third separation unit D) is preferably adapted to separate any remaining extractant used in process step b) from the second aqueous phase. Method according to the method of the present invention Step d) is preferably carried out in a third separation unit D). The third separation unit D) may be an additional extraction unit, but is preferably a thermal separation unit, such as a distillation column, a fractionation column, a rectification column or the like, from which the skilled artisan is known and apparently suitable for this purpose. Any device that is separated is in the device according to the invention.

The device according to the invention may further comprise a fourth separation unit E). The fourth separation unit E) preferably comprises at least one thermal separation device for separating at least a portion of the extractant from the extraction phase, obtaining an extract comprising at least one component ii. according to the invention, corresponding to the method of the invention Method step e). It is also possible to comprise at least one further thermal separation device for separating at least one of the at least one component according to the invention from the extract, step f) of the method corresponding to the method according to the invention. It is conceivable to use a thermal decomposition apparatus which is known to the person skilled in the art and which is obviously suitable for carrying out the separation of process steps e) and f) for use in a plant according to the invention, such as a distillation column, a fractionation column or a rectification column or the like. At least one.

Further separation units can also be included in the device according to the invention. An example of a preferred further separation unit is one which is suitable for separating at least one from a mixture comprising at least two components ii. according to the invention (for example, a mixture obtained in step f according to the method of the invention) The separation unit of component ii. corresponds to step j) of the method according to the invention. These additional separation units are preferably thermal separation units, preferably comprising at least one distillation column, fractionation column, rectification column or the like.

The device according to the invention preferably comprises at least one fourth separation unit E) and/or at least one further separation unit and first extraction unit A3) And/or a conduit between the first separation unit A4) for guiding at least one of methacrylic acid and a phase comprising methacrylic acid to return to at least one of the first extraction unit A3) and the first separation unit A4) By.

The apparatus according to the invention optionally comprises at least one second esterification unit K) for esterifying at least one component ii. to obtain an ester phase, preferably in a second extraction unit B), a third separation unit D And downstream of at least one of the fourth separation unit E). Process step k) is preferably carried out in a second esterification unit. The details regarding the second esterification unit are the same as those of the first esterification unit A5) described above.

The device according to the invention may also comprise at least one ester separation unit M) for the at least partial separation of one or more esters, in particular for at least partially separating at least one ester phase obtained from at least one second esterification unit. The ester corresponds to process step m) of the process according to the invention. Any device known to the skilled artisan and apparently suitable for separating esters can be used as the ester separation unit M). The thermal separation unit of the type mentioned, as well as the crystallization unit, the extraction unit and the phase separation unit, are preferred as the ester separation unit M) in the apparatus according to the invention.

At least one further purification unit N) may also be provided in the apparatus according to the invention for purifying the esters and/or esters obtained in the second esterification unit or separated in at least one ester separation unit. Process step n) of the process according to the invention is preferably carried out in a further purification unit N). The details of this additional purification unit correspond to those purification units described in relation to the first esterification unit A5).

The device according to the invention may also comprise at least one second extraction sample An ester conduit between element B) and at least one of a second esterification unit K), an ester separation unit M) and an additional purification unit N) for purifying at least one ester. At least one ester conduit is adapted to direct at least one ester from at least one of the second esterification unit K), the ester separation unit M) and the further purification unit N) for purifying the at least one ester to the second extraction unit B) Here, at least one ester can be used arbitrarily as an extractant.

In a preferred aspect of the apparatus according to the invention, the apparatus additionally comprises an MTBE splitting unit AA1) upstream of the gas phase oxidation unit A1). MTBE splitting unit, and adapted to divide the catalyst in the present art is well known and constitute a part of those familiar with the general knowledge in the art, as for example in Ullmann's Encyclopedia of Industrial Chemistry, 5 th Edition, Vol.A4, p.488; V .Fattore, M.Massi Mauri, G.Oriani, G.Paret , Hydrocarbon Processing, August 1981, p.101-106; Ullmann's Encyclopedia of Industrial Chemistry, 5 th Edition, Vol.A16, p.543-550; A. Chauvel, G. Lefebvre, "Petrochemical Processes, Technical and Economic Characteristics", Vol. 1, Éditions Technip, Paris, 1989, p. 213 et seq.; US 5, 336, 841, US 4, 570, 026 and the references cited therein.

The isobutylene separation unit S1) is preferably arranged between the MTBE splitting unit AA1) and the gas phase oxidation unit A1) and each is in fluid communication. The isobutylene separation unit S1) is suitable for separating the isobutene phase and preferably also separating the methanol phase from the effluent of the second catalyst reaction zone, the effluent comprising isobutylene and methanol as the main components. The isobutylene separation unit S1) can be an extractor or a knot At least one of a crystallizer, a column, a distillation apparatus, a rectification apparatus, a membrane, a pervaporation apparatus, a phase separator, and a cleaning apparatus. The isobutylene separation unit S1) preferably comprises an isobutylene phase outlet and a methanol phase outlet. The isobutylene phase outlet is preferably optionally connected to the gas phase oxidation unit via an intermediate unit, such as a purification unit, a heat exchanger, and/or a pressure regulator. The methanol phase outlet is preferably optionally connected to at least one of the first esterification unit and the second esterification unit via an intermediate methanol purification unit. Any device known to the skilled artisan and apparently suitable for purifying methanol can be included as a methanol purification unit. Examples of suitable purification units preferably comprise at least one distillation unit, crystallizer, extractor, column or cleaning unit, more preferably at least one distillation unit. An example of a purification unit for methanol is described in EP 1 254 887.

The invention also relates to a method according to the invention, wherein the method occurs in a device according to the invention.

The invention is illustrated more closely by the following graphical and non-limiting examples.

According to the specific example of Fig. 2, the C ₄ compound is introduced into the gas phase oxidation unit A1 where it is oxidized to methacrylic acid by a one- or two-stage catalytic gas phase oxidation reaction. The inlet of the C ₄ compound, oxygen, steam and inert diluent gas to the gas phase oxidation unit A1 is not shown. The C ₄ compound can be provided from the MTBE splitting unit AA1 (not shown) via an isobutylene separation unit S1 (not shown). The methacrylic acid gas phase obtained in the gas phase oxidation unit A1 is guided via line 1 to a quench unit A2 where it is cooled and absorbed into water or an aqueous phase to form an aqueous phase comprising methacrylic acid. The quench liquid is not shown to the inlet of the quench unit A2. The aqueous phase of methacrylic acid is directed via line 2 to a first extraction unit A3 where it is extracted with an organic solvent as an extractant to form an organic phase and an aqueous phase (first aqueous phase according to the process of the invention). The two phases are separated in the first extraction unit A3.

The organic phase from the first extraction unit A3 is directed via line 3 to a first separation unit A4 where it is distilled to separate methacrylic acid and an extractant. The extractant can be recycled via line 6 to the first extraction unit A3. Methacrylic acid can be collected via line 5 and optionally purified in a downstream purification unit or unit or the like (not shown) or can be directed via line 4 to first esterification unit A5, optionally purified (not shown). In the first esterification unit A5, methacrylic acid can be esterified with, for example, methanol (for example, methanol separated from the MTBE split phase in the separation unit S1 (not shown) to form methyl methacrylate. It is also possible to esterify methacrylic acid in the first esterification unit A5 with the above other alcohols. The esters produced in the first esterification unit A5 are collected via line 7 and optionally polymerized in polymerization unit A6 (not shown), optionally purified in the middle and/or downstream.

The aqueous phase separated in the first extraction unit A3 is led via line 8 to a second extraction unit B where it is extracted with an organic solvent as a second extractant to form an aqueous phase (corresponding to the second aqueous phase of the process of the invention) ) and the organic phase. The aqueous phase is directed via line 9 to a third separation unit D where the remaining extractant from the second extraction step can be at least partially separated and optionally recycled via line 25 to the second separation unit B. The remaining aqueous phase of the third aqueous phase corresponding to the process of the invention can be recycled via line 20 to, for example, a gas phase oxidation unit A1 (a conduit not shown) for use as treated water, directed to a biological purification unit (not shown) or discharged . Organic separated in the second extraction unit B The phase can be directed via line 10 to a fourth separation unit E where at least one component ii. can be separated. At least one component ii. of at least a portion separated in the fourth separation unit E can be collected via line 11 and optionally purified (not shown). If the mixture of component ii. is separated in the fourth separation unit E, the mixture can be directed to another separation unit to separate the components ii. from each other (not shown). If methacrylic acid or a phase comprising methacrylic acid is separated in the fourth separation unit E, this methacrylic acid or phase comprising methacrylic acid can be directed via line 15 to the first extraction unit A3 or via line 16 to First separation unit A4. It is also possible to direct at least one component ii. of at least a portion separated in the fourth separation unit E to the second esterification unit K via line 14. Any one of the organic phase and the aqueous phase separated in the second extraction unit B or the third separation unit D may be guided to the second esterification unit K. In the second esterification unit K, at least one component ii. is esterified with an alcohol to form the corresponding ester. If the alcohol is methanol, this methanol can be introduced, for example, from the MTBE splitter AA1 via separation unit S1, optionally by intermediate purification (not shown). If the ester phase obtained in the second esterification unit K contains more than one ester, at least one ester can be separated in the ester separation unit M. At least one ester can be purified in a downstream ester purification unit N (not shown). At least one ester obtained by one or more of the second esterification unit K, the ester separation unit M and the ester purification unit N may be introduced to the second extraction unit B to be used as an extractant.

experiment method Measurement of partition coefficient (k-value)

The aqueous phase containing a predetermined amount of acetic acid is combined with the same volume of organic solvent (extractant). The two phases are shaken and/or stirred at 50 ° C for 15-30 minutes to ensure an equilibrium distribution of acetic acid throughout the aqueous and organic phases. The mixture was then allowed to separate and return to an organic phase and an aqueous phase at 50 ° C, and the two phases were separated from each other. The amount of acetic acid present in the separated organic phase is measured by gas chromatography (GC) or high pressure liquid chromatography (HPLC).

‧HPLC: Agilent 1200

‧ Pumps: Quaternary Pumps

○ Flow rate: 1.0 ml / min

○ Stop time: 30 minutes

○ Hours: 5 minutes

○ Control pressure: 190 bar, maximum 250 bar

‧Autosampler: Autosampler

○ Injection volume: 20 microliters

‧ Tower oven: including tower switch control

○ Temperature: 30 ° C

○ Tower: Agilent SB-Aq

▪ Maße length 150 mm, d _i 4.6 mm, 3.5 micron material

‧Detector MWD or DAD

○UV 210 nm, 241 nm, 254 nm, 265 nm

(better with DAD)

‧GC: Perkin Elmer Autosystem

‧Autosampler: Perkin Elmer

○ cleaning solvent THF

○ injection volume 1.0 microliter

‧syringe:

○Split split ratio 100

○ Temperature program 200 ° C

‧ Flow rate Constant pressure 12.0

‧ Tower oven:

○ Tower J&W Scientific DB 225

○ Size length 30 meters, d _i 0.25 mm, 0.25 micron material

○Operating time: 18.3 minutes

‧Detector FID

○Set point 260°C

Example 1:

This example was carried out in the experimental plant according to Figure 3. The artificial first aqueous phase was mixed and stored in B-100. The first aqueous phase is filtered, preheated and pumped to the top of the liquid-liquid-extraction column K-100. K-100 is a glass-filled and jacketed extraction column that is temperature controlled to 50 °C via a heat transfer fluid in a double jacket. Fluid-fluid-extraction is a reverse flow mode of operation while directing the feed to the top of the column and directing the extractant to the bottom of the column. Ethyl acetate was used as the extractant with an extractant/feed ratio of 2.5. The K-100 was filled in a random filling mode and operated in a continuous phase pulsation mode (10 mm stroke and 56 minutes ^-1 frequency). The extractant used is continuously regenerated and thus operates in a continuous recirculation loop. The extract phase is preheated and fed to an extractant regeneration glass type distillation column K-200. Distillation column K-200 is structured to be packed and operated by a steam heated evaporator and a condenser with cooling water. The distillate stains the regenerated extractant and collects it in a storage container. The sump effluent is the final extract that is directed to the separation unit. The second aqueous phase was extracted from the bottom of K-100, preheated to 90 ° C and fed to a second extractant regenerated glass distillation column K-300. The distillation column K-300 is continuously packed in a structured packing and continuously operated by a steam heated evaporator and a cooling water operated condenser. The third aqueous phase is extracted from the sump of K-300 and fed into the final tank for the third aqueous phase. The regenerated extractant is extracted at the top of the K-300 and fed to the storage vessel along with the regenerated extractant from K-200.

ACA=acetic acid

AA=Acrylic

MAA=methacrylic acid

PRA=propionic acid

EtAC=ethyl acetate

EtOH=ethanol

ACK=Acetone

FOL = formaldehyde

A1‧‧‧ gas phase oxidation unit

A2‧‧‧Quench unit

A3‧‧‧First extraction unit

A4‧‧‧ first separation unit

A5‧‧‧First esterification unit

B‧‧‧Second separation unit

Second extraction unit

D‧‧‧ third separation unit

E‧‧‧fourth separation unit

K‧‧‧Secondization unit

M‧‧‧ ester separation unit

N‧‧‧ ester purification unit

1-25‧‧‧ pipeline

K-100‧‧‧Liquid-Liquid Extraction Tower

K-200‧‧‧Extractant Regeneration Glass Distillation Tower

K-300‧‧‧Second extractant regeneration glass type distillation tower

Figure 1 is a flow chart showing a preferred embodiment of the method in accordance with the present invention.

Figure 2 is a diagram showing a specific example of the apparatus according to the present invention.

Figure 3 shows the experimental plant performing Example 1.

Claims (26)

A method of preparing at least one of methacrylic acid and methacrylic acid comprising the following method steps: a1) gas phase oxidation of at least one C ₄ compound to obtain a reaction phase comprising methacrylic acid; a2) The reaction phase is quenched to obtain a crude aqueous phase comprising methacrylic acid; a3) at least a portion of the methacrylic acid is extracted from the crude aqueous phase comprising methacrylic acid to an organic solvent to obtain a methacrylic acid-containing a crude organic phase of an aqueous phase, wherein the first aqueous phase comprises the following components: i. at least 65% by weight water based on the total weight of the first aqueous phase, and ii. based on the total weight of the first aqueous phase Not more than 35% by weight of at least one organic compound (other than the organic solvent used as the extractant in process step a3), wherein the sum of the weights of i. and ii. is 100% by weight; a4) at least a portion of the The base acrylic acid is separated from the crude organic phase obtained in process step a3) and optionally purified; a5) optionally at least a portion of the methacrylate obtained in step a4); b) obtained in step a3) At least part of The first aqueous phase is extracted with an extractant to form an extract phase comprising component ii. and a second aqueous phase, the component ii. of the second aqueous phase being depleted compared to the first aqueous phase; c) The extract phase obtained in step b) at least partially separates the second aqueous phase obtained in step b); d) optionally at least partially separating at least one organic compound from the second aqueous phase obtained in step c), Obtaining a third aqueous phase, at least one organic compound in the third aqueous phase is depleted compared to the second aqueous phase; e) optionally separating at least a portion of the extractant from the extracting phase to obtain at least one Extract of component ii. The method of claim 1, wherein the first aqueous phase comprises the following components: i. 65-99.9 wt% water based on the total weight of the first aqueous phase, and ii. From 0.1 to 35% by weight, based on the weight of the at least one organic compound (except for the organic solvent used as the extractant in process step a3). A method of treating an aqueous phase comprising at least one organic compound, comprising the following method steps: a) providing a first aqueous phase comprising: i. at least 65% by weight based on the total weight of the first aqueous phase Water, and ii. not more than 35% by weight, based on the total weight of the first aqueous phase, of at least one organic compound, wherein the sum of the weights of i. and ii. is 100% by weight, b) extracting at least a portion of the first aqueous phase with an extractant to form an extract phase comprising at least one component ii. and a second aqueous phase, at least one of the second aqueous phases being compared to the first aqueous phase a component ii. is depleted; c) at least partially separating the second aqueous phase from the extract phase; d) optionally at least partially separating at least one organic compound from the second aqueous phase obtained in step c) Obtaining a third aqueous phase, at least one organic compound in the third aqueous phase being depleted compared to the second aqueous phase; e) optionally separating at least a portion of the extractant from the extracting phase to obtain at least one group Part ii. Extract. The method of claim 3, wherein the first aqueous phase comprises the following components: i. 65-99.9 wt% water based on the total weight of the first aqueous phase, and ii. 0.1 to 35% by weight, based on the weight, of at least one organic compound. According to the method of claim 1 or 2, further comprising the following method steps: f) separating at least a portion of at least one component ii. from the extract. The method of claim 1 or 2, wherein the second aqueous phase comprises no more than 5.0% by weight of the organic compound based on the total weight of the second aqueous phase (except for the extractant used in method step b) other than). According to the method of claim 1 or 2, wherein the third The aqueous phase comprises no more than 3% by weight of organic compound based on the total weight of the third aqueous phase (other than the extractant used in process step b). The method of claim 1 or 2, wherein in the further method step g), the third aqueous phase is subjected to at least one biological purification treatment. The method of claim 8, wherein the at least one biological purification treatment is at least one of an aerobic treatment and an anaerobic treatment. The method of claim 1 or 2, wherein in a further method step h), at least a portion of the extractant separated in at least one of method steps d) and e) is recycled to method step b ). The method of claim 1 or 2, wherein the at least one component ii. obtained in step f) is a mixture of at least two components ii. and wherein in a further method step j) At least one component ii. is at least partially separated from the mixture. The method of claim 1 or 2, wherein the at least one organic compound of the component ii. is at least one organic compound selected from the group consisting of carboxylic acids, aldehydes and ketones. The method of claim 1 or 2, wherein the extractant used in method step b) is characterized by at least one of the following properties: i) determined at 25 ° C according to the method described herein The average k-value of acetic acid in the system extractant-water is in the range from 0.1 to 100; Ii) the evaporation enthalpy does not exceed 2260 仟 joules/kg; iii) the boiling point ranges from 35 to 140 ° C; iv) the solubility in water at 25 ° C temperature does not exceed 150 gram / liter. The method of claim 1 or 2, wherein the extractant used in method step b) is characterized by at least two of the following properties: i) determined at 25 ° C according to the method described herein The average k-value of acetic acid in the system extractant-water is in the range from 0.1 to 100; ii) the evaporating enthalpy does not exceed 2260 仟 joules/kg; iii) the boiling point is in the range from 35 to 140 ° C; iv) The solubility in water at a temperature of 25 ° C does not exceed 150 g / liter. The method of claim 1 or 2, wherein the extractant used in method step b) is characterized by at least three of the following properties: i) determined at 25 ° C according to the method described herein The average k-value of acetic acid in the system extractant-water is in the range from 0.1 to 100; ii) the evaporating enthalpy does not exceed 2260 仟 joules/kg; iii) the boiling point is in the range from 35 to 140 ° C; iv) The solubility in water at a temperature of 25 ° C does not exceed 150 g / liter. The method of claim 1 or 2, wherein the extractant used in method step b) is characterized by at least four of the following properties: i) determined at 25 ° C according to the method described herein The average k-value of acetic acid in the system extractant-water is in the range from 0.1 to 100; ii) the evaporating enthalpy does not exceed 2260 仟 joules/kg; iii) the boiling point is in the range from 35 to 140 ° C; iv) The solubility in water at a temperature of 25 ° C does not exceed 150 g / liter. The method of claim 1 or 2, wherein at least one component ii. is at least one of acetic acid, acrylic acid, propionic acid, and methacrylic acid. The method of claim 17, wherein at least one component ii. separated in at least one of method steps e), f) and j) is or comprises methacrylic acid, and the methacrylic acid is At least a part of it is added to the crude aqueous phase obtained in process step a2) or to the crude organic phase obtained in process step a3). The method according to claim 1 or 2, wherein at least a part of at least one component ii. separated in at least one of method steps e), f) and j) or in method step a3) At least a portion of the first aqueous phase obtained is subjected to the following process steps: k) esterification to obtain an ester phase comprising at least one ester. According to the method of claim 19, wherein the ester phase Contains at least two esters. According to the method of claim 19, further comprising the following method steps: m) at least partially separating at least one ester from the ester phase; n) optionally purifying at least one ester isolated in process step m). The method of claim 19, wherein at least a portion of the at least one ester obtained in at least one of steps k), m) and n) is used as the extractant in process step b). The method of claim 19, wherein the at least one ester is based on a C ₁ -C ₄ carboxylic acid and a C ₁ -C ₄ alcohol. The method according to claim 1 or 2, further comprising the steps of: aa1) splitting methyl tert-butyl ether to obtain at least one C ₄ compound and methanol, wherein at least a portion of at least one C ₄ compound is used as The feed is supplied to the gas phase oxidation of at least one of process step a1). According to the method of claim 24, the methanol obtained in process step aa1) is supplied to process step k). An apparatus for a method of producing at least one of methacrylic acid and methacrylic acid according to claim 1 of the patent application, comprising at least the following components in fluid communication with each other: A1) gas phase oxidation unit, A2 ) quench unit, A3) a first extraction unit, A4) a first separation unit, A5) a random first esterification unit, and B) a second extraction unit.