Method for recovering organotin catalysts

Abstract

The organotin catalyst recycling method consists of the following sequential steps: 1) (i) water, at least one C1-C 12 Alcohol, water, and at least one C1-C 12 The method comprises the steps of: 1) preparing a mixture containing (ii) a polar solvent selected from a mixture with an alcohol, (ii) an organotin catalyst residual solution S1 obtained from the synthesis of an aminoalkyl (meth)acrylate compound, and (iii) at least one organic extraction solvent ES1, and performing liquid-liquid extraction LLE1 of the mixture using the organic extraction solvent ES1 to obtain an organic solution OS1 and an aqueous solution AS1; 2) performing distillation D1 of the organic solution OS1 at temperature T1 and pressure P1 to obtain an organic solution OS1' and an organic distillate OD1; and 3) performing distillation D2 of the organic solution OS1' at temperature T2 and pressure P2 to obtain an organic solution OS1'' and an organic distillate OD2.

Description

Technical Field

[0001] The present invention relates to a new method for recycling an organotin catalyst, which is carried out after the method for synthesizing aminoalkyl (meth)acrylate.

Background Art

[0002] Aminoalkyl (meth)acrylates such as 2-dimethylaminoethyl (meth)acrylate and its quaternized derivatives are well-known monomers used in the preparation of polymers used in many industries, such as water treatment, papermaking, home care and personal care, or the oil and gas industry, such as oil & gas recovery enhancement, hydraulic fracturing, water shutoff, etc.

[0003] These monomers are obtained by transesterification of an alkyl (meth)acrylate catalyzed by an organometallic derivative with an amino alcohol. The choice of catalyst depends on various criteria such as the nature of the aminoalkyl (meth)acrylate used, the nature of the alcohol, or the nature of the synthesis process.

[0004] In the case of 2-dimethylaminoethyl (meth)acrylate, it is well-known to use an organotin derivative, especially a dialkyltin oxide such as dibutyltin oxide (DBTO), as a catalyst. The role of the catalyst is to shift the equilibrium so that more 2-dimethylaminoethyl (meth)acrylate is produced and the formation of impurities is reduced. After the reaction, the catalyst can be reused in a new synthesis method, but during these reuse cycles, the DBTO catalyst tends to deactivate and needs to be replaced regularly. This results in costly, difficult-to-manage and handle toxic waste.

[0005] As DBTO deactivation begins, the reaction product contains more impurities. These impurities are Michael adducts of alcohols that react with (meth)acrylic acid, such as methanol or dimethylaminoethanol, including methyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, or (meth)acrylic acid. These impurities, produced as by-products, reduce the quality of the resulting 2-dimethylaminoethyl (meth)acrylate. This reduction in monomer quality affects the performance of polymers prepared from such monomers.

[0006] Many attempts have been made to reuse the catalyst as efficiently as possible.

[0007] Reference JP2008-231003 describes the synthesis of polyfunctional acrylates and the recovery of catalysts by the addition of strong acids.

[0008] Reference WO03 / 028888 describes the recovery of transesterification catalysts by extraction with water.

[0009] Reference WO2019 / 196048 describes a method for producing 2-dimethylaminoethyl (meth)acrylate using a mixture of fresh and recycled catalysts.

[0010] As an alternative to organotin catalysts, tetraalcoxy titanate catalysts have been used in the synthesis of 2-dimethylaminoethyl (meth)acrylate, as described in US 7,268,251. Such titanium catalysts require an activation step involving ligand exchange by first reacting tetraisopropyl titanate with dimethylaminoethanol, which generates a side flow of isopropanol that must be further disposed of. This activation step is energy-intensive and generates a side flow of waste. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] JP2008-231003 [Patent Document 2] WO03 / 028888 [Patent Document 3] WO2019 / 196048 [Patent Document 4] US 7,268,251 [Patent Document 5] WO 2016 / 124837 [Overview of the project] [Problems that the invention aims to solve]

[0012] Despite the greater or lesser success of all these attempts, there is still a need for improved catalyst recovery methods that would enable greater reuse and thereby reduce the environmental impact of (meth)acrylate aminoalkyl synthesis methods. [Means for solving the problem]

[0013] The recycling method according to the present invention is in line with environmental awareness principles and the impact that industry and humanity have on the planet. This recycling method enables better recovery of the catalyst and improved performance of the subsequent (meth)acrylate aminoalkyl synthesis method, thereby reducing overall emissions of greenhouse gases such as CO2.

[0014] The present invention relates to a method for synthesizing aminoalkyl (meth)acrylates, for example, a novel method for reusing organotin catalysts after the synthesis of 2-dimethylaminoethyl (meth)acrylate.

[0015] More specifically, the organotin catalyst recycling method consists of the following sequential (i.e., continuous or successive) steps: 1) (i) Water, at least one type of C1-C 12 Alcohol, water, and at least one C1-C 12A mixture is prepared comprising (ii) a polar solvent selected from a mixture with an alcohol, (ii) an organotin catalyst residue solution S1 obtained from the synthesis of an aminoalkyl (meth)acrylate compound, and (iii) at least one organic extraction solvent ES1. The process involves performing a liquid-liquid extraction LLE1 of this mixture using an organic extraction solvent ES1 to obtain an organic solution OS1 and an aqueous solution AS1. 2) Distillation D1 of organic solution OS1 at temperature T1 and pressure P1 is performed on the organic solution OS 1' and a step to obtain the organic distillate OD1, 3) Organic solution OS at temperature T2 and pressure P2 1' Distillation D2 is performed on the organic solution OS 1" And the process of obtaining the organic distillate OD2, organic solution OS 1" However, it contains 2-40 wt% organotin catalyst residue. Temperature T2 is higher than temperature T1, and / or pressure P2 is lower than pressure P1. Process and Includes, In step 1), (i) when the polar solvent is added, (ii) the organotin catalyst residual solution S1 and (iii) at least one organic extraction solvent ES1 are already mixed, or (i) the polar solvent, (ii) the organotin catalyst residual solution S1, and (iii) at least one organic extraction solvent ES1 are added simultaneously.

[0016] Another object of the present invention relates to a (meth)acrylate aminoalkyl synthesis process that uses at least a portion of a recycled organotin catalyst obtained by the recycling method of the present invention.

[0017] Another object of the present invention relates to polymers obtained from a method for synthesizing aminoalkyl (meth)acrylates using at least a portion of recycled organotin catalysts obtained by the recycling method of the present invention. [Brief explanation of the drawing]

[0018] [Figure 1] This diagram illustrates the continuous mode using a single liquid-liquid extraction LLE. [Figure 2] This diagram illustrates the continuous mode using two liquid-liquid extraction LLEs. [Figure 3] This diagram illustrates a continuous mode using n liquid-liquid extraction LLEs. [Modes for carrying out the invention]

[0019] As used herein, the expression "A and / or B" means "A or B, or A and B."

[0020] As used herein, the term "heavie" refers to Michael adducts of alcohols that react with methyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, or (meth)acrylic acid, such as methanol or dimethylaminoethanol.

[0021] The present invention also includes all possible combinations of the various embodiments disclosed, whether preferred or exemplary, if they are not mutually exclusive. Furthermore, where ranges of values ​​are indicated, the end values ​​are part of these ranges. The disclosure also includes all combinations between the end values ​​of these ranges. For example, the range “1 to 20, preferably 5 to 15” implies the disclosure of the ranges “1 to 5”, “1 to 15”, “5 to 20”, and “15 to 20”.

[0022] Liquid-liquid extraction LLE1 of organotin catalyst residual solution S1 The reuse method can be carried out after any (meth)acrylate aminoalkyl synthesis method as described in the prior art, using alkyl (meth)acrylate and 2-dimethylaminoethanol as starting materials. Advantageously, the alkyl (meth)acrylate has an alkyl chain of 1 to 6 carbon atoms (preferably a linear alkyl chain), and more preferably, the alkyl (meth)acrylate is methyl (meth)acrylate. Preferably, the reuse method is carried out after a synthesis method of 2-dimethylaminoethyl (meth)acrylate with an organotin catalyst. Thus, the organotin catalyst residue solution S1 preferably results from the synthesis of 2-dimethylaminoethyl (meth)acrylate.

[0023] In the method for synthesizing (meth)acrylate aminoalkyl, the reaction is carried out in the presence of a reaction solvent that forms an azeotropic mixture with a lower alcohol formed as a byproduct during the synthesis. This azeotropic mixture is distilled during the synthesis to shift the reaction to the formation of (meth)acrylate aminoalkyl.

[0024] The reaction solvent is advantageously selected from saturated or unsaturated linear, branched, or cyclic hydrocarbons containing 3 to 16 carbon atoms. Preferably, the solvent is selected from n-hexane, isomers of n-hexane, and mixtures thereof.

[0025] At the end of the (meth)acrylate aminoalkyl synthesis method, the azeotropic mixture is distilled to obtain a reaction mixture generally containing (meth)acrylate aminoalkyl, catalyst (organotin catalyst) residue, and trace amounts of raw materials, such as (meth)acrylate, 2-dimethylaminoethanol, alcohol, and reaction solvent. Generally, a distillation step is performed to separate different compounds. After such a distillation step, an organotin catalyst residue solution S1 containing the catalyst and high-boiling compound, such as Michael adduct, is obtained.

[0026] According to a preferred embodiment, the organotin catalyst residue solution S1 results from the synthesis of aminoalkyl (meth)acrylate (preferably 2-dimethylaminoethyl (meth)acrylate) in the presence of dialkyltin oxide, preferably dibutyltin oxide.

[0027] According to the present invention, in the first step (liquid-liquid extraction LLE1 step), (ii) the organotin catalyst residue solution S1 is mixed with a polar solvent selected from at least (iii) an extraction solvent ES1 and (i) water or at least one C1-C 12 alcohol or a mixture of water and at least one C1-C 12 alcohol.

[0028] Generally, the organotin catalyst residue solution S1 contains Michael adducts, high-boiling compounds, organotin catalysts, and possibly trace amounts of starting materials and aminoalkyl (meth)acrylates.

[0029] The organotin catalyst residue solution S1 advantageously contains an organotin catalyst between 1 and 40% by weight, preferably between 3 and 30% by weight, more preferably between 5 and 20% by weight.

[0030] The organic extraction solvent ES1 is advantageously selected from linear saturated hydrocarbons containing 3 to 16 carbons, linear unsaturated hydrocarbons containing 3 to 16 carbons, branched saturated hydrocarbons containing 3 to 16 carbons, branched unsaturated hydrocarbons containing 3 to 16 carbons, cyclic saturated hydrocarbons containing 3 to 16 carbons, cyclic unsaturated hydrocarbons containing 3 to 16 carbons, and mixtures thereof. Preferably, the extraction organic solvent ES1 is a saturated alkane having a carbon chain in the range of C3-C 12 It may be a mixture of C3-C 12 alkanes.

[0031] Examples of the organic extraction solvent ES1 used in the present invention include n-propane, n-butane, n-pentane, n-hexane, n-heptane, n-decane, toluene, benzene, xylene, cyclohexane, isooctane, C3-C6 and C10 Examples include isomers of n-alkanes and mixtures thereof.

[0032] Preferably, the organic extraction ES1 solvent is selected from n-propane, n-butane, n-pentane, n-hexane, n-heptane, n-decane, their isomers, and mixtures thereof. More preferably, the organic extraction ES1 solvent contains at least 50% by mass of n-hexane, even more preferably at least 60% by mass, even more preferably at least 70% by mass, even more preferably at least 80% by mass, and even more preferably at least 85% by mass of n-hexane.

[0033] As already mentioned, step 1) involves water and lower alcohol (C1-C1). 12 ), and a polar solvent selected from mixtures thereof. Lower alcohols (C1-C 12 The solvent comprises methanol, ethanol, and mixtures thereof. Preferably, this polar solvent contains at least 70% by mass of water, more preferably at least 80% by mass, and even more preferably at least 90% by mass of water.

[0034] In step 1), the mass ratio of the organic extraction solvent ES1 to the polar solvent is advantageously between 20:1 and 2:1, preferably between 15:1 and 2.5:1, more preferably between 12:1 and 3:1, and even more preferably between 9:1 and 4:1.

[0035] Liquid-liquid extraction LLE1 can be carried out by any means known to those skilled in the art.

[0036] Advantageously, the liquid-liquid extraction LLE1 includes at least one mixing step and one separation step.

[0037] Liquid-liquid extraction LLE1 is advantageously carried out at temperatures between 1 and 90°C, preferably between 10 and 80°C, and more preferably between 20 and 70°C.

[0038] In certain embodiments, LLE1 is performed using a continuous extraction column.

[0039] The mixing step (polar solvent + ES1 + S1) can be carried out using any mixing apparatus, for example, using a stirring blade, centrifugal pump, static mixer, or rotor / stator combination. Preferably, the mixing step is carried out using a stirring blade. It consists of (i) water, at least one C1-C 12 Alcohol, water, and at least one C1-C 12 The process involves mixing a polar solvent selected from a mixture with alcohols, (ii) an organotin catalyst residue solution S1 obtained from the synthesis of an aminoalkyl (meth)acrylate compound, and (iii) at least one organic extraction solvent ES1.

[0040] The mixing time (polar solvent + ES1 + S1) is advantageously between 5 seconds and 60 minutes, preferably between 1 minute and 30 minutes, and more preferably between 90 seconds and 10 minutes.

[0041] The rotational speed of the mixture (polar solvent + ES1 + S1) is advantageously between 10 and 10,000 rpm, preferably between 100 and 5,000 rpm, and more preferably between 200 and 1,000 rpm (rpm = revolutions per minute).

[0042] The mixing time and rotation speed (polar solvent + ES1 + S1) depend on (1) the design of the stirrer and the volume of the mixing vessel, (2) the amount of organotin catalyst in the organotin catalyst residual solution S1, and (3) the ratio of the solvent (polar + ES1) to the organotin catalyst residual solution S1. Since these parameters correspond to conventional settings, those skilled in the art can easily determine them.

[0043] The separation process allows for the formation of two separate phases, an aqueous phase and an organic phase. The separation process can be achieved by any one of the following methods: centrifuge, coalescer, cyclone, column, gravity sedimentation, and any combination thereof. Preferably, the separation process is achieved by gravity sedimentation.

[0044] The separation process is advantageously carried out for a period of 10 seconds to 60 minutes, preferably 30 seconds to 30 minutes, and more preferably 1 minute to 10 minutes.

[0045] At the end of the liquid-liquid extraction LLE1, an organic solution OS1 and an aqueous suspension AS1 are obtained.

[0046] Generally, organic solution OS1 contains Michael adducts, organotin catalyst residues, organic extraction solvent ES1, and possibly trace amounts of (meth)acrylate aminoalkyl.

[0047] The organic solution OS1 advantageously contains organotin catalyst residue between 1 and 40% by mass, preferably between 2 and 30% by mass, and more preferably between 3 and 20% by mass.

[0048] Generally, aqueous suspension AS1 contains some organotin catalysts and starting materials, as well as aminoalkyl (meth)acrylate.

[0049] The aqueous suspension AS1 advantageously contains organotin catalyst residue between 0.1 and 10% by mass, preferably between 0.15 and 5% by mass, and more preferably between 0.5% and 2% by mass.

[0050] Liquid-liquid extraction of aqueous suspension AS1 LLE2 In certain embodiments, the aqueous suspension AS1 is treated by liquid-liquid extraction LLE2 using the extraction solvent ES2.

[0051] This liquid-liquid extraction LLE2 can be performed using the same apparatus as described for liquid-liquid extraction LLE1.

[0052] The organic extraction solvent ES2 is advantageously an organic solvent.

[0053] The organic extraction solvent ES2 is advantageously selected from linear saturated hydrocarbons containing 3 to 16 carbon atoms, linear unsaturated hydrocarbons containing 3 to 16 carbon atoms, branched saturated hydrocarbons containing 3 to 16 carbon atoms, branched unsaturated hydrocarbons containing 3 to 16 carbon atoms, cyclic saturated hydrocarbons containing 3 to 16 carbon atoms, cyclic unsaturated hydrocarbons containing 3 to 16 carbon atoms, and mixtures thereof. Preferably, the organic extraction solvent ES2 is C3-C 12 It is a saturated alkane having a carbon chain in the range of C3~C 12 It may also be a mixture of alkanes.

[0054] Organic HCl solvent ES n Examples of (where n is an integer greater than or equal to 1) include n-propane, n-butane, n-pentane, n-hexane, hexane, n-heptane, n-decane, toluene, benzene, xylene, cyclohexane, isooctane, their isomers, and mixtures thereof, preferably an organic extraction solvent ES. n These are n-hexane and its isomers.

[0055] The ratio of the extraction solvent ES2 to the aqueous suspension AS1 is advantageously between 20:1 and 2:1, preferably between 15:1 and 2.5:1, more preferably between 12:1 and 3:1, and even more preferably between 9:1 and 4:1.

[0056] There is no specific order for adding the extraction solvent ES2 and the aqueous solution AS1. The addition of the extraction solvent can be divided into several steps. The extraction solvent ES2 may be added first, or the aqueous suspension AS1 may be added first, or they may be added alternately (i.e., a first fraction of the extraction solvent ES2, followed by a first fraction of the aqueous suspension AS1, then a second fraction of the extraction solvent ES2, followed by a second fraction of the aqueous suspension AS1, or vice versa), or they may be added simultaneously. Preferably, the extraction solvent ES2 is added first.

[0057] Liquid-liquid extraction LLE2 can be carried out by any means known to those skilled in the art. Advantageously, liquid-liquid extraction LLE2 includes at least one mixing step and one separation step.

[0058] Liquid-liquid extraction LLE2 is advantageously carried out at temperatures between 1 and 90°C, preferably between 10 and 80°C, and more preferably between 20 and 70°C.

[0059] The mixing time is advantageously between 5 seconds and 30 minutes, preferably between 1 minute and 10 minutes, and more preferably between 90 seconds and 5 minutes.

[0060] The mixing rotation speed is advantageously between 50 and 10,000 rpm, preferably between 100 and 5,000 rpm, and more preferably between 200 and 1,000 rpm.

[0061] The mixing time and rotation speed depend on (1) the design of the stirrer and the volume of the mixing vessel, (2) the amount of organotin catalyst residue in the aqueous suspension AS1, and (3) the ratio of the extraction solvent ES2 to the aqueous solution AS1. Since these parameters are conventional settings, those skilled in the art can easily determine them.

[0062] The second separation step allows for the formation of two separated phases, an aqueous phase and an organic phase. The separation step is advantageously performed by gravity sedimentation.

[0063] The separation process is advantageously carried out for a period of 10 seconds to 60 minutes, preferably 30 seconds to 10 minutes, and more preferably 1 minute to 5 minutes.

[0064] At the end of the liquid-liquid extraction LLE2, an organic solution OS2 and an aqueous suspension AS2 are obtained.

[0065] In a preferred embodiment, the organic solution OS2 is reused in part or whole to form or complete the organic extraction solvent ES1 in the first liquid-liquid extract LLE1.

[0066] In certain embodiments, the aqueous suspension AS2 is discarded.

[0067] In a preferred embodiment, the aqueous suspension AS2 is distilled, and the resulting aqueous distilled phase is partially or completely reused in a first liquid-liquid extract LLE1 or a second liquid-liquid extract LLE2.

[0068] In certain embodiments, at least one carboxylic acid is added to the aqueous suspension AS1 before performing the liquid-liquid extraction LLE2. The carboxylic acid is advantageously selected from acrylic acid, methacrylic acid, acetic acid, formic acid, itaconic acid, maleic acid, citric acid, fumaric acid, tartaric acid, and mixtures thereof. Preferably, the carboxylic acid is acrylic acid.

[0069] The mass ratio of carboxylic acid to organotin catalyst residue in the aqueous suspension AS1 is advantageously between 0.005 and 0.2, preferably between 0.01 and 0.15, and more preferably between 0.02 and 0.1.

[0070] Liquid-liquid extraction LLE2 is advantageously carried out at temperatures between 1 and 200°C, preferably between 5 and 120°C, more preferably between 5 and 80°C, and more preferably between 10 and 70°C.

[0071] The liquid-liquid extraction process is advantageously carried out at an absolute pressure between 0.1 and 20 bar, preferably between 0.5 and 5 bar, more preferably between 0.8 and 2 bar, and more preferably between 0.9 and 1.1 bar, and more preferably at atmospheric pressure.

[0072] Optionally, after LLE1, a distillation step of AS1 is performed to obtain an aqueous phase having a water content of 90% by mass or more. This aqueous phase is advantageously reused for liquid-liquid extraction.

[0073] Distillation D1 In the second step, distillation D1 is performed on the organic solution OS1, and the organic solution OS 1' To obtain.

[0074] Distillation D1 can be carried out in any distillation apparatus known to those skilled in the art, such as a flash evaporator, thin-film evaporator, wiped-film evaporator, short-stroke distillation apparatus, fall-film type, agitated reactor, or reaction vessel. Preferably, distillation D1 is carried out in a flash evaporator.

[0075] Distillation D1 is advantageously carried out at a temperature T1 which is between 5 and 180°C, preferably between 10 and 150°C, and more preferably between 15 and 80°C.

[0076] The distillation D1 is advantageously carried out at an absolute pressure P1 which is between 0.01 and 1 bar, preferably between 0.05 and 0.8 bar, and more preferably between 0.3 and 0.6 bar.

[0077] At the end of distillation D1, the organic solution OS 1' This can be obtained.

[0078] organic solution OS 1' The solution advantageously contains organotin catalyst residue between 1 and 40% by mass, preferably between 2 and 35% by mass, and more preferably between 3 and 30% by mass.

[0079] Distillation D1 consists of distillate (fraction DF1) and organic solution OS 1' This will result in...

[0080] In certain embodiments, the distilled fraction DF1 can be partially or entirely reused for the first and / or second liquid-liquid extract LLE2, with or without a pretreatment step (as shown in Figure 2).

[0081] In certain embodiments, at least one carboxylic acid is added to the organic solution OS1 before distillation D1. The carboxylic acid is advantageously selected from acrylic acid, methacrylic acid, acetic acid, formic acid, itaconic acid, maleic acid, citric acid, fumaric acid, tartaric acid, and mixtures thereof. Preferably, the carboxylic acid is acrylic acid.

[0082] The mass ratio of carboxylic acid to organotin catalyst residue in the organic solution OS1 is advantageously between 0.005 and 0.2, preferably between 0.01 and 0.15, and more preferably between 0.02 and 0.1.

[0083] Distillation D2 In the third step, distilled D2 is converted into organic solution OS 1' This was performed on organic solution OS 1" To obtain.

[0084] Distillation D2 can be carried out in any distillation device known to those skilled in the art, such as a flash evaporator, thin-film evaporator, wiped-film evaporator, short-stroke distillation apparatus, drip-film type, agitated reactor, or reaction vessel. Preferably, distillation D2 is carried out in a flash evaporator.

[0085] Distillation D2 is advantageously carried out at a temperature T2 which is between 20 and 220°C, preferably between 30 and 200°C, and more preferably between 50 and 190°C.

[0086] Distillation D2 is advantageously carried out at an absolute pressure P2 between 0.001 and 1 bar, preferably between 0.01 and 0.5 bar, and more preferably between 0.02 and 0.2 bar.

[0087] The temperature T2 of distillation D2 is higher than the temperature T1 of distillation D1, and / or the pressure P2 of distillation D2 is lower than the pressure P1 of distillation D1.

[0088] At the end of distillation D2, the organic solution OS 1" And the distilled fraction DF2 is obtained.

[0089] organic solution OS 1" Advantageously, the solution contains organotin catalyst residue between 2 and 40% by mass, preferably between 3 and 40% by mass, and more preferably between 5 and 40% by mass.

[0090] The distilled fraction DF2 generally consists of Michael adducts and organic extraction solvent ES. n(where n is an integer greater than or equal to 1), and (meth)acrylate aminoalkyl. The distilled fraction DF2 can be disposed of or further treated by the method described in reference WO 2016 / 124837, which describes the heat treatment of high-boiling compounds for the recovery and reuse of 2-dimethylaminoethanol and / or (meth)acrylate alkyl and / or (meth)acrylate 2-dimethylaminoethyl.

[0091] In certain embodiments, before distillation D2, at least one carboxylic acid is used in the organic solution OS. 1' It is added to the mixture. The carboxylic acid is advantageously selected from acrylic acid, methacrylic acid, acetic acid, formic acid, itaconic acid, maleic acid, citric acid, fumaric acid, tartaric acid, and mixtures thereof. Preferably, the carboxylic acid is acrylic acid.

[0092] organic solution OS 1' The mass ratio of the carboxylic acid to the organotin catalyst residue is advantageously between 0.005 and 0.2, preferably between 0.01 and 0.15, and more preferably between 0.02 and 0.1.

[0093] The resulting organic solution OS 1" At least a portion of it can be reused as a catalyst in the (meth)acrylate aminoalkyl synthesis method. Advantageously, based on the total amount of catalyst in the new (meth)acrylate aminoalkyl synthesis method, 100% by mass of the catalyst can be reused in the organic solution OS. 1" The catalyst is derived from, preferably 90% by mass or less, more preferably 80% by mass or less, more preferably 70% by mass or less, more preferably 60% by mass or less, and more preferably 50% by mass or less. The remaining catalyst is advantageously a fresh organotin catalyst.

[0094] "Fresh" here means that it is not a recycled organotin catalyst.

[0095] Optional step 4) In a particular embodiment of the present invention, the method for reusing an organotin catalyst includes an optional step 4).

[0096] Optional step 4) involves at least the extraction solvent ES n Using an aqueous suspension AS n-1 Further liquid-liquid extraction LLE n Performing organic solution OS n and aqueous suspension AS n This involves obtaining (where n is a non-zero integer > 1).

[0097] More specifically, the reuse method involves one or more of the following further liquid-liquid extraction LLEs. n+1 (where n is an integer greater than or equal to 1): - (i) Aqueous suspension AS n (ii) at least one extraction solvent ES n Prepare a mixture containing the following: Liquid-liquid extraction of this mixture LLE n+1 Perform the following steps to create an organic solution OS n+1 and aqueous suspension AS n+1 process to obtain It can include...

[0098] In this particular embodiment, organic solution OS n+1 At least a portion of is distilled by steps 2) and 3) of claim 1 to form (respectfully) organic solution OS' n+1 , and then organic solution OS'' n+1 To obtain.

[0099] The resulting organic solution OS'' n+1' At least a portion of it can be used as a catalyst for the synthesis of (meth)acrylate aminoalkyl. Advantageously, based on the total amount of catalyst, 100% by mass of the catalyst in this synthesis method can be reused in the organic solution OS''. n+1 The catalyst is derived from, preferably 90% by mass or less, more preferably 80% by mass or less, more preferably 70% by mass or less, more preferably 60% by mass or less, and more preferably 50% by mass or less. The remaining catalyst is advantageously a fresh organotin catalyst.

[0100] In this particular embodiment, aqueous suspension AS n+1This refers to partial or whole liquid-liquid extraction (LLE), with or without a pretreatment step. n+2 Used in organic solution OS n+1 This refers to partial or whole liquid-liquid extraction (LLE), with or without a pretreatment step. n It will be reused.

[0101] In this particular embodiment, the extraction solvent ES n It is advantageously composed of at least one organic solvent, which is advantageously a saturated or unsaturated linear, branched, or cyclic hydrocarbon containing 3 to 16 carbon atoms, preferably C3 to C6. 12 A saturated alkane having a carbon chain in the range of ES is selected, and mixtures thereof, and the total amount of polar solvent and organic solvent is the extraction solvent ES. n This corresponds to 100% by mass.

[0102] ED Solvent ES n Examples of organic extraction solvents used include n-propane, n-butane, n-pentane, n-hexane, hexane, n-heptane, n-decane, toluene, benzene, xylene, cyclohexane, isooctane, their isomers, and mixtures thereof.

[0103] In a particular embodiment, an aqueous suspension AS n+1 It is advantageous to distill it (D3) and use it as an aqueous suspension AS n+1' and organic solution OS n+1' To obtain.

[0104] Distillation D3 can be carried out in any distillation apparatus known to those skilled in the art, such as a flash evaporator, thin-film evaporator, wiped-film evaporator, short-stroke distillation apparatus, drip-film type, agitated reactor, or reaction vessel. Preferably, distillation D3 is carried out in a flash evaporator.

[0105] Distillation D3 is advantageously carried out at a temperature T3 which is between 10 and 100°C, preferably between 30 and 100°C, and more preferably between 50 and 100°C.

[0106] Distillation D3 is advantageously carried out at an absolute pressure P3 between 0.001 and 1 bar, preferably between 0.05 and 1 bar, and more preferably between 0.1 and 1 bar.

[0107] In certain embodiments, organic solution OS n+1 To be advantageous, LLE n It is reused partially or entirely, with or without pretreatment.

[0108] Specific embodiments of the present invention In certain embodiments, distillation D1 and distillation D2 are carried out using the same distillation device.

[0109] In certain embodiments, organic solution OS 1" Before being reused in the synthesis of (meth)acrylate aminoalkyl, at least one carboxylic acid and / or one alcohol is added to the organic solution OS 1" It is added to it.

[0110] The carboxylic acid is advantageously selected from acrylic acid, methacrylic acid, acetic acid, formic acid, itaconic acid, maleic acid, citric acid, fumaric acid, tartaric acid, and mixtures thereof. Preferably, the carboxylic acid is acrylic acid.

[0111] Alcohol is advantageously lower alcohol (C1-C1). 12 For example, the alcohol is selected from methanol, ethanol, propanol, butanol, and mixtures thereof. Preferably, the alcohol is methanol.

[0112] organic solution OS 1" The molar ratio of (1) carboxylic acid and / or alcohol to (2) organotin catalyst residue is advantageously between 1:50 and 1:2, preferably between 1:30 and 1:5, and more preferably between 1:20 and 1:10.

[0113] The reuse method can be carried out in batches or as a semi-continuous or continuous process. Preferably, the reuse method is carried out as a continuous process.

[0114] In certain embodiments, the reuse method of the present invention is carried out as a continuous process. A “continuous process” according to the present invention means that at least one flow enters continuously (ES n (Advantageously, the organotin catalyst residual solution S1), from which at least two flows exit in succession (advantageously, one (LS1) is the aqueous phase AS n This corresponds to the other (LS2) being the organic phase OS n It should be understood that this is a process equivalent to (where n is an integer greater than or equal to 1). The continuous process according to the present invention can be operated without interruption for several days to several months.

[0115] In this particular embodiment, the residence time in the distillation device (D1+D2) is between 30 seconds and 60 minutes, preferably between 1 minute and 30 minutes, and more preferably between 5 minutes and 20 minutes.

[0116] In this particular embodiment, the mass ratio of LS1 to LS2 is advantageously between 0.01 and 1, preferably between 0.1 and 1, and more preferably between 0.15 and 1 (where n is an integer of 1 or more).

[0117] Another object of the present invention relates to a (meth)acrylate aminoalkyl synthesis process that uses at least a portion of a recycled organotin catalyst obtained by the recycling method of the present invention.

[0118] Advantageously, based on the total amount of catalyst, at least 70% by mass or less of the catalyst used in this synthesis is derived from the organotin catalyst recycling method of the present invention, preferably 60% by mass or less, and more preferably 50% by mass or less. The remaining catalyst is advantageously a fresh organotin catalyst.

[0119] Another object of the present invention relates to polymers obtained from a method for synthesizing aminoalkyl (meth)acrylates using at least a portion of recycled organotin catalysts obtained by the recycling method of the present invention.

[0120] The present invention and its advantages will not be limited, but will be better illustrated by the following embodiments provided to illustrate the invention.

[0121] List of abbreviations: ADAME: 2-dimethylaminoethyl acrylate MA: Methyl acrylate DMOH: Dimethylaminoethanol Hx: Hexane DBTO: Dibutyltin oxide Ptz: Phenothiazine GC-FID: Gas chromatography flame ionization detector Hv: Heavy content MeOH: methanol ICP-OES: Inductively Coupled Plasma-Emission Spectroscopy AZDN: Azobisisobutyronitrile [Examples]

[0122] (Example 1) ADAME Synthesis Add 89 g of MA, 46 g of DMOH, 13 g of Hx, 1.84 g of DBTO, and 0.11 g of Ptz to a 250 mL three-necked round-bottom flask. Start the magnetic stirrer at 500 RPM. A column with an inner diameter of 20 mm and a height of 50 cm, filled with 3 mm Dixon rings, is attached to one end, and a cooling condenser containing glycol water at -10°C is attached to the top of the column. The temperature at the top of the column is monitored and adjusted by changing the reflux ratio, and the collection of the distillate is controlled using a metering valve. A round-bottom flask is heated using a heating plate, and the external temperature is set to 110°C. By maintaining the top temperature at 48-53°C using a reflux ratio control valve, the distillate is continuously collected at the top of the column. Each time 10 mL of distillate is collected, 7 mL of Hx is added back into the reaction medium. The reaction continues until it is no longer possible to maintain the column top temperature below 53.5°C by maximizing the reflux ratio. The reaction mixture is analyzed by GC-FID. The GC Agilent 7820A is used with a 30m DB-WAX UI column with an inner diameter of 0.50 μm. The temperature is set to 80°C for 5 minutes, then increased by 4°C per second to 122°C, left at 122°C for 2 minutes, then increased again by 35°C per second to 240°C, left at 240°C for 9 minutes. The injector is set to 250°C and helium is used as the phase carrier. 1 μL is injected at a split ratio of 1:100. A flame ionization detector is used for detection. Five sample standards with different compositions are injected together with ADAME, DMOH, MA, MeOH, and Hx to establish a calibration curve. The response coefficient obtained with ADAME is used to quantify the heavy component after a 16-minute retention period. As a result, the ADAME concentration was measured at 64.6% wt, DMOH at 0.9 wt%, and high molecular weight heavy components at 0.35%. The conversion rate of ADAME is ((%ADAME / (%ADAME+%DMOH+%heavy component)) * The calculation is 100) = 98.2%.

[0123] Next, using the same configuration, the reaction mixture is distilled under vacuum to recover the ADAME monomer. When the top column temperature reaches 78°C at 40 mbar absolute pressure, the different fractions are collected sequentially down to 10 mbar absolute pressure until the final ADAME fraction is obtained. The composition of the ADAME fraction, as measured by GC-FID, is 99.5% wt ADAME, 1500 ppm DMOH, 100 ppm MeOH, 1500 ppm MA, and 505 ppm Hv. The concentrated solution in the round-bottom flask corresponds to the catalyst residue solution S1.

[0124] The tin concentration is measured by ICP-OES using an Agilent ICPE-5800. 0.1 g of S1 is weighed into 8 ml of concentrated hydrochloric acid and 2 ml of nitric acid. The sample is placed in a sealed crucible. The crucible is heated in a 600 W microwave for 90 minutes until it reaches 150°C. The resulting solution is diluted 100-fold and sprayed at 0.7 L / min. The emission intensity is measured at a wavelength of 189,925 nm and quantified based on the tin standard solution. The tin concentration is corrected using the molecular weight assuming a pure DBTO structure. 2.87% wt of Sn is measured, which corresponds to 6% wt of DBTO.

[0125] (Example 2) (This invention) 500 g of Hx and 250 g of the catalyst residue solution S1 prepared in Example 1 are added to a 1 L reactor equipped with a mechanical stirrer defined by a 4-blade 90° impeller. Set the stirrer to 500 RPM and add 50g of water after 30 seconds. Stop stirring after 1 minute and let the solution stand for 1 minute to allow it to settle. The upper and lower phases are collected separately, corresponding to OS1 and AS1, respectively. In a 1L batch distillation apparatus, OS1 was distilled at 60°C; 300mbar for 30 minutes, and the Hx phase in the distillate DF1 was collected. The lower phase was OS 1' It corresponds to this. Next, distillation is continued at 120°C; 5 mbar until no more distillate can be collected. 35 g was obtained from the bottom concentrate, which is OS 1" It corresponds to this. OS 1" The tin composition inside was measured according to ICP-OES and found to be 6%wt, which corresponds to 12.6%wt of DBTO.

[0126] (Example 3) (counterexample) 500 g of Hx and 250 g of the catalyst residue solution S1 prepared in Example 1 are added to a 1 L reactor equipped with a mechanical stirrer defined by a 4-blade 90° impeller. Set the stirrer to 500 RPM and add 50g of water after 30 seconds. Stop stirring after 1 minute and let the solution stand for 1 minute to allow it to settle. The upper and lower phases are collected separately, corresponding to OS1 and AS1, respectively. OS1 is distilled in a 1L batch distillation apparatus at 60°C; 300mbar for 30 minutes, and the Hx phase in the distillate DF1 is collected. 55 g was obtained from the bottom concentrate, which is OS 1' It corresponds to this. OS 1' The tin composition inside was measured according to ICP-OES and found to be 3.80%wt, which corresponds to 8.0%wt of DBTO.

[0127] (Example 3-2) (counterexample) 50 g of water and 250 g of the catalyst residue solution S1 prepared in Example 1 are added to a 1 L reactor equipped with a mechanical stirrer defined by a 4-blade 90° impeller. Set the stirrer to 500 RPM and add 500 g of Hx after 30 seconds. Stop stirring after 1 minute and let the solution stand for 1 minute to allow it to settle. The upper and lower phases are collected separately, corresponding to OS1 and AS1, respectively. In a 1 L batch distillation apparatus, OS1 is distilled at 60°C; 300 mbar for 30 minutes to collect the Hx phase in the distillate DF1. Distillation is then continued at 120°C; 5 mbar until no more distillate can be collected. 45 g of the bottom concentrate is obtained, which is OS 1" It corresponds to this. OS 1" The tin composition inside was measured according to ICP-OES and found to be 0.5% wt, which is equivalent to 1.05% wt of DBTO.

[0128] (Example 3-3) (counterexample) 500 g of Hx and 250 g of the catalyst residue solution S1 prepared in Example 1 are added to a 1 L reactor equipped with a mechanical stirrer defined by a 4-blade 90° impeller. Set the stirrer to 500 RPM and add 300g of water after 30 seconds. Stop stirring after 1 minute and let the solution stand for 1 minute to allow it to settle. A stable emulsion is obtained. The lower and upper phases cannot be separated.

[0129] (Example 4) (This invention) 500 g of Hx and 250 g of the catalyst residue solution S1 prepared in Example 1 are added to a 1 L reactor equipped with a mechanical stirrer defined by a 4-blade 90° impeller. Set the stirrer to 500 RPM and add 50g of water after 30 seconds. Stop stirring after 1 minute and let the solution stand for 1 minute to allow it to settle. The upper phase corresponding to OS1 is collected. The lower phase corresponding to AS1 is left in the reactor, 500g of Hx is added, followed by stirring at 500 RPM for 1 minute, and then settling for 1 minute. The upper and lower phases are collected separately, corresponding to OS2 and AS2, respectively. In a 1L batch distillation apparatus, OS2 was distilled at 60°C; 300mbar for 30 minutes, and the Hx phase in the distillate DF1 was collected. The lower phase was OS 2' It corresponds to this. Next, distillation is continued at 120°C; 5 mbar until no more distillate can be collected. Bottom concentrate OS 2" Then 40g is obtained. OS 2" The tin composition inside was measured according to ICP-OES and found to be 7.3%wt, which corresponds to 15.4%wt of recycled DBTO.

[0130] (Example 5) (This invention) This embodiment corresponds to the specific configuration shown in Figure 3.

[0131] 6 L of Hx is added to a 7 L Kuhni stirring column, which consists of a 10-stage, 4-blade, 90° impeller. Set the stirrer to 100 RPM. Continuously add the catalyst residue solution S1 prepared in Example 1 to the first shelf of the column at a rate of 250 g / hour. A homogeneous mixture of Hx / water (50:50) is continuously added at a rate of 100 g / hour to the second shelf adjacent to the top of the column. Hx is continuously added at a rate of 200 g / hour on the last shelf of the column. The organic phase OS1 and aqueous phase AS1 are collected at the top and bottom of the column, respectively. OS1 was distilled in a rotary evaporator at 60°C; 300 mbar for 30 minutes to obtain the Hx phase in the distillate DF1 and the organic phase OS at the bottom. 1' Collect them. Next, distillation OS 1' Continue at 120°C; 5 mbar until no more distillate can be collected. Bottom concentrate OS 1" Then 45g / hour can be obtained. Using ICP-OES to OS 1" The tin composition inside was measured to be 8.1% wt, which corresponds to 17% wt of recycled DBTO.

[0132] (Example 6) ADAME using recycled DBTO in Examples 2-5 The recycled DBTO produced in Examples 2-5 is used in a new ADAME synthesis method as described in Example 1. However, the amount of catalyst is adjusted to start at the same DBTO concentration. The final composition of the ADAME fraction is summarized in Table 1.

[0133] The composition of the ADAME fraction, as measured by GC-FID, is ADAME 99.5% wt, DMOH 1500 ppm, MeOH 100 ppm, MA 1500 ppm, and Hv 505 ppm.

[0134] [Table 1]

[0135] (Example 7) ADAME Polymer Synthesis and Practical Testing In the following examples, the ADAME material synthesized in Example 6 is quaternized with methyl chloride. In a 2L autoclave reactor equipped with a four-bladed impeller and a double jacket, the reactor is degassed with a nitrogen stream for 30 minutes and then sealed. Using a gear pump, add ADAME at a rate of 236 g / hour for 3 hours. When the volume reaches 200 ml, start stirring the reactor and add methyl chloride at a rate of 128 g / hour for 2 hours. Use a double jacket to regulate the temperature to reach a maximum of 45°C. After 1 hour, begin adding water at a rate of 216 g / hour for 1 hour. The mixture is left at 40°C for 1 hour while stirring, then cooled and degassed to reach atmospheric pressure. Next, dilute chloromethylated ADAME (ADC80) with 10g of water. 1190 g of the final product is obtained at an activity concentration of 80% by mass. This final product is then polymerized as described in the following process: Add 137 g of acrylamide solution (50% wt in water), 437 g of water, and 926 g of ADC80 to a 2 L beaker. The mixture is cooled to 0°C under stirring, and the pH is adjusted to 3.6 with phosphoric acid. Transfer this solution to a Dewar flask and degas it with nitrogen for 15 minutes. Next, add 1 mg of AZDN to 1 mL of water. Maintain nitrogen degassing for 15 minutes and monitor the temperature. At the end of the degassing time, 2 mg of sodium hypophosphite per 1 mL of water is added to the Dewar flask, followed by 6 mg of sodium persulfate per 1 mL of water and 4 mg of Mohr's salt dissolved in 1 mL of water. The polymerization reaction begins. Next, the reaction is left in an adiabatic state until the temperature reaches a plateau between 80 and 85°C. Next, the resulting gel is left at plateau temperature for 30 minutes, and then crushed into small pieces. Dry the ground ingredients in an oven at 70°C for 2 hours. Next, these polymer particles are crushed to produce a powder with a particle size in the range of 1.5 to 2.5 mm.

[0136] UL viscosity is measured at 60 revolutions / min between 23–25°C using a Brookfield viscometer equipped with a UL adapter (1M saline solution, i.e., 0.1 mass percent polymer in 1M sodium chloride solution).

[0137] Insolubility is measured by transferring 1 g of polymer solution to 200 ml of water at 20°C, stirring for 2 hours, and then filtering the dissolved solution through a 4 cm diameter filter with 200 μm pores to drain the solution.

[0138] The insolubility number corresponds to the number of aggregates on the filter, which were visually counted after the entire solution had passed through the filter. The results are summarized in Table 2.

[0139] [Table 2]

[0140] (Example 8) ADAME synthesis from Example 1 The catalyst residue solution S1 produced in Example 1 is reused directly in the ADAME synthesis method described in Example 1 without any further treatment. However, the raw materials, methyl acrylate and dimethylaminoethanol, are prepared by referring to the monomers remaining in the catalyst residue solution S1. This operation is repeated 10 times. The results are summarized in Table 3.

[0141] [Table 3]

[0142] (Example 9) ADAME synthesis using the reuse method of Example 4 between each cycle Organic solution OS produced in Example 4 1" This is used in the new method described in Example 1. However, the raw materials, methyl acrylate and dimethylaminoethanol, are used in the organic solution OS. 1" Adjust the mixture by referring to the residual monomers inside. Repeat this process 10 times. Summarize the results in Table 4.

[0143] [Table 4]

[0144] (Example 10) ADAME synthesis: Use the reuse method of Example 4 between each cycle, and mix with 50% fresh catalyst. Organic solution OS produced in Example 4 1" This is used in the new method described in Example 1. However, the raw materials, methyl acrylate and dimethylaminoethanol, are used in the organic solution OS. 1" Adjust by referring to the residual monomers inside, OS 1" Half of it is replaced with fresh DBTO according to its equivalent amount based on its Sn content. This operation is repeated 10 times. The results are summarized in Table 5.

[0145] [Table 5]

[0146] (Example 11) Synthesis and Practical Testing of ADAME Polymers

[0147] [Table 6]

[0148] The ADAME monomers of Examples 8, 9, and 10 were quaternized, and the polymers were prepared according to Example 7. In order to observe the effects of different recycling methods according to the present invention, the numerical values of UL viscosity and insolubility were compared. The results are summarized in Table 6, Table 7, and Table 8.

[0149]

Table 7

[0150]

Table 8

Explanation of Signs

[0151] S1 Catalyst Residual Solution ES1 Organic Extraction Solvent LLE1 Liquid-Liquid Extraction OS1 Organic Solution AS1 Aqueous Suspension D1 Distillation OD1 Organic Distillate OS 1' Organic Solution D2 Distillation OD2 Organic Effluent OS 1" Organic Solution LLE2 Liquid-Liquid Extraction OS2 Organic Solution AS2 Aqueous Suspension DF1 Fraction DF2 Fraction ES n Organic Extraction Solvent LLE n Liquid-Liquid Extraction OS n Organic Solution AS n Aqueous Suspension

Claims

1. A method for reusing organotin catalyst residue, comprising the following sequential steps: 1) (i) Water, at least one type of C 1 ~C 12 Alcohol, water, and at least one type of C 1 ~C 12 (ii) A polar solvent selected from a mixture with an alcohol, (ii) a residual organotin catalyst solution S obtained from the synthesis of an aminoalkyl (meth)acrylate compound. 1 , and (iii) at least one organic extraction solvent ES 1 Prepare a mixture containing the following: Organic extraction solvent ES 1 Use this to perform liquid-liquid extraction LLE 1 of this mixture to obtain an organic solution OS 1 and an aqueous solution AS 1 and the step of obtaining 2) Temperature T 1 and pressure P 1 Organic solution OS 1 Distillation D 1 Perform the following steps to create an organic solution OS 1' and organic distillates OD 1 The process of obtaining, 3) Temperature T 2 and pressure P 2 Organic solution OS 1' Distillation D 2 Perform the following steps to create an organic solution OS 1" and organic distillates OD 2 This is the process of obtaining organic solution OS 1" It contains 2 to 40 wt% organotin catalyst residue. temperature T 2 is temperature T 1 Higher and / or pressure P 2 pressure P 1 lower Process and Includes, In step 1), (i) when a polar solvent is added, (ii) organotin catalyst residual solution S 1 and (iii) at least one organic extraction solvent ES 1 Either (i) a polar solvent, or (ii) a residual solution of organotin catalyst S is already mixed, or (i) a polar solvent, or (ii) an organotin catalyst. 1 , and (iii) at least one organic extraction solvent ES 1 These are added at the same time. How to reuse.

2. Organotin catalyst residual solution S 1 However, the recycling method according to claim 1 is obtained from the synthesis of 2-dimethylaminoethyl (meth)acrylate.

3. Organotin catalyst residual solution S 1 The reuse method according to claim 2, which is obtained from the synthesis of 2-dimethylaminoethyl (meth)acrylate in the presence of dialkyltin oxide.

4. The recycling method according to claim 3, wherein the dialkyltin oxide is dibutyltin oxide.

5. Organic HCl solvent ES 1 The recycling method according to claim 1, wherein the hydrocarbons are selected from linear saturated hydrocarbons containing 3 to 16 carbon atoms, linear unsaturated hydrocarbons containing 3 to 16 carbon atoms, branched saturated hydrocarbons containing 3 to 16 carbon atoms, branched unsaturated hydrocarbons containing 3 to 16 carbon atoms, cyclic saturated hydrocarbons containing 3 to 16 carbon atoms, cyclic unsaturated hydrocarbons containing 3 to 16 carbon atoms, and mixtures thereof.

6. Organic HCl solvent ES 1 The recycling method according to claim 1, wherein it contains at least 50% by mass of n-hexane.

7. The recycling method according to claim 1, wherein the polar solvent contains at least 80% by mass of water.

8. Organic HCl solvent ES 1 And ES containing polar solvents in a ratio between 20:1 and 2:1 1 The recycling method according to claim 1, wherein the mass ratio of polar solvents is as described above.

9. Liquid-liquid extraction LLE 1 The recycling method according to claim 1, further comprising at least one mixing step and one separation step.

10. The reuse method according to claim 9, wherein the mixing step is carried out for 5 seconds to 60 minutes and involves mechanical stirring with a rotational speed between 10 and 10,000 rpm.

11. The recycling method according to claim 9, wherein the separation step is carried out by gravity sedimentation.

12. The reuse method according to claim 9, wherein the separation continues for a period of 10 seconds to 60 minutes.

13. Distillation D 1 However, the temperature T is included in the range of 5 to 180°C. 1 The reuse method according to claim 1, which is carried out by [the specified method].

14. Distillation D 1 However, the absolute pressure P included in the range of 0.01 to 1 bar 1 The reuse method according to claim 1, which is carried out by [the specified method].

15. Distillation D 2 However, the temperature T is included in the range of 20 to 220°C. 2 The reuse method according to claim 1, which is carried out by [the specified method].

16. Distillation D 2 However, the absolute pressure P included in the range of 0.001 to 1 bar 2 The reuse method according to claim 1, which is carried out by [the specified method].

17. One or more of the following further liquid-liquid extractions LLE n+1 (where n is an integer greater than or equal to 1): - (i) Aqueous AS n (ii) Residual solution S of organotin catalyst produced from the synthesis of aminoalkyl (meth)acrylate compounds 1 , and (iii) at least one organic extraction solvent ES n Prepare a mixture containing the following, and perform a liquid-liquid extraction of this mixture. n+1 Perform the following steps to create an organic solution OS n+1 and aqueous solution AS n+1 process to obtain The reuse method according to claim 1, including the method described in claim 1.

18. organic solution OS n+1 At least a portion of is distilled by steps 2) and 3) of claim 1 to form the organic solution OS' n+1 , and then organic solution OS'' n+1 The reuse method according to claim 17, which obtains the result.

19. Aqueous AS n However, with or without a pretreatment step, partial or whole liquid-liquid extraction LLE n+1 Used in organic solution OS n+1 However, with or without a pretreatment step, partial or whole liquid-liquid extraction LLE n The reuse method according to claim 17, wherein the product is reused.

20. Distillation D 1 and distillation D 2 The reuse method according to claim 1, wherein the process is carried out within the same distillation apparatus.

21. The reuse method according to claim 1, which is carried out as a continuous process.

22. A method for synthesizing aminoalkyl (meth)acrylate, comprising using at least a portion of the recycled organotin catalyst obtained according to claim 1.

23. A polymer obtained from a method for synthesizing aminoalkyl (meth)acrylates using at least a portion of a recycled organotin catalyst obtained according to claim 1.

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