Intermittent synthesis method of amino alkyl (meth) acrylate

Abstract

The invention relates to a novel intermittent synthesis method of aminoalkyl (meth) acrylate. The method comprises the following steps: 1) preparing a mixture M1 containing the following components in percentage by weight: 50-97.899% of alkyl (meth) acrylate; 0.1 to 40% by weight of an alkanolamine; 0.001 to 10 wt% of a catalyst; 2 to 30 wt% of a solvent; 2) preparing a mixture M2: (i) heating the mixture M1 to a temperature T1 of 40-120 DEG C, and removing alkyl alcohol formed in the reaction process by azeotropic distillation; the azeotropic distillation is carried out at T1 for 30 to 720 min, (ii) during the azeotropic distillation, further continuously adding 15 to 85 wt% of alkanolamine based on the total amount of alkanolamine used in steps 1) and 2); and 3) distilling the mixture M2 to recover the amino alkyl (meth) acrylate. The process improves the yield and purity of the synthesized aminoalkyl (meth) acrylate, reduces the waste produced, and allows the catalyst to have optimal recyclability, thereby reducing the emissions of greenhouse gases and waste as a whole.

Description

Technical Field

[0001] This invention relates to a novel batch synthesis method for aminoalkyl methacrylates. Background Technology

[0002] (Meth)acrylate aminoalkyl esters, such as (meth)acrylate 2-dimethylaminoethyl ester and its quaternized derivatives, are well known monomers for the preparation of polymers used in many industries, such as water treatment, papermaking, home and personal care, or the oil and gas industry, such as enhanced oil recovery, hydraulic fracturing, water shut-off, etc.

[0003] These monomers are obtained via transesterification reactions of alkyl (meth)acrylates with alkanolamines catalyzed by organometallic derivatives. The choice of catalyst depends on various criteria, such as the nature of the aminoalkyl (meth)acrylate or alcohol used, or the nature of the synthetic process. The catalyst's role is to shift the equilibrium, producing more aminoalkyl (meth)acrylates and reducing the formation of impurities.

[0004] After the reaction, the catalyst can be recycled in new synthesis processes, but during these cycles, the catalyst often deactivates, leading to the formation of more impurities. These impurities, called heavies, are Michael adducts of alcohols and / or amines such as methanol or dimethylaminoethanol, reacting at the double bonds of methyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, or (meth)acrylic acid. The formation of these impurities reduces reaction yield, increases waste generation, and reduces the quality of the produced aminoalkyl (meth)acrylates, which affects the properties of polymers prepared from such aminoalkyl (meth)acrylates.

[0005] Numerous attempts have been made to reduce the formation of heavy materials. In document WO2019196048, the applicant proposed replacing part of the original catalyst with a new catalyst in consecutive synthesis batches, thereby extending the lifespan of the recycled catalyst and resulting in higher yields and purity of the produced (meth)acrylate aminoalkyl esters. However, this solution requires increased catalyst consumption.

[0006] Document US4059617 describes a batch synthesis of dimethylaminoethyl methacrylate by continuously adding a mixture of dimethylaminoethanol and methyl methacrylate at approximately the same rate as the consumption of the amino alcohol reactants during the reaction. This improves the yield and reduces the formation of heavy substances.

[0007] Alternative solutions are disclosed in WO2013045786 and WO2016124837. In these documents, heavy materials are thermally decomposed to reverse their formation. However, such processes require a large amount of energy.

[0008] The applicant has discovered that by starting the synthesis from a specific mixture composition and continuously adding at least one alkanolamine throughout the batch synthesis process, the reaction yield and purity of aminoalkyl methacrylates obtained in a batch process can be improved, waste generated can be reduced, and optimal catalyst recyclability can be achieved. Compared with classical methods for the synthesis of aminoalkyl methacrylates, the method according to the invention also improves the kinetics of the synthesis of aminoalkyl methacrylates, and even further increases the yield, while reducing the total energy required for synthesis.

[0009] The novel batch synthesis method for aminoalkyl methacrylates of this invention aligns with environmental awareness and the principles of industrial and human impact on the planet. This novel batch synthesis method improves the yield and purity of synthesized aminoalkyl methacrylates, reduces waste generation, and optimizes catalyst recyclability, thereby reducing overall greenhouse gas (e.g., CO2) and waste emissions. Summary of the Invention

[0010] This invention relates to a novel batch synthesis method for aminoalkyl methacrylates.

[0011] More specifically, the batch synthesis method of the (meth)acrylate aminoalkyl ester includes the following sequential steps:

[0012] 1) Prepare a mixture M1 comprising the following:

[0013] (i) 50 to 97.899% by weight of at least one alkyl (meth)acrylate;

[0014] (ii) 0.1 to 40% by weight of at least one alkanolamine;

[0015] (iii) at least one catalyst, ranging from 0.001 to 10% by weight;

[0016] (iv) 2 to 30% by weight of at least one solvent;

[0017] Based on the total weight of mixture M1;

[0018] 2) Mixture M2 is prepared by the following method:

[0019] (i) The mixture M1 is heated to a temperature T1 of 40°C to 120°C, and the alkyl alcohols formed during the reaction are removed by azeotropic distillation; the azeotropic distillation is carried out at T1 for 30 to 720 min.

[0020] (ii) During the azeotropic distillation process, at least one alkanolamine is further added continuously in an amount of 15 to 85% by weight based on the total amount of alkanolamines used in steps 1) and 2).

[0021] 3) Recover (meth)acrylate aminoalkyl esters by distilling mixture M2.

[0022] Another object of the present invention relates to aminoalkyl methacrylates and their salts obtained by the intermittent synthesis method according to the present invention.

[0023] Another object of the present invention relates to polymers obtained by polymerizing aminoalkyl methacrylates obtained by the intermittent synthesis method according to the present invention. Detailed Implementation

[0024] As used herein, the term "polymer" refers to a homopolymer or copolymer. A "homogeneous polymer" is a polymer prepared from only one monomer, while a "copolymer" is a polymer obtained from at least two different monomers.

[0025] As used in this article, the expression "A and / or B" means "A, or B, or A and B".

[0026] This invention also includes all possible combinations of the various disclosed embodiments, whether they are preferred or exemplary embodiments, provided they are not mutually exclusive. Furthermore, where numerical ranges are specified, the endpoints are part of those ranges. This disclosure also includes all combinations between the endpoints of these ranges. For example, the range “1 to 20, preferably 5 to 15” implicitly discloses the ranges “1 to 5”, “1 to 15”, “5 to 20”, and “15 to 20”.

[0027] Step 1)

[0028] Mixture M1 contains:

[0029] (i) 50 to 97.899% by weight of at least one alkyl (meth)acrylate;

[0030] (ii) 0.1 to 40% by weight of at least one alkanolamine;

[0031] (iii) 0.001 to 10% of at least one catalyst;

[0032] (iv) 2 to 30% by weight of at least one solvent;

[0033] Based on the total weight of mixture M1;

[0034] Mixture M1 is advantageously prepared under stirring.

[0035] Mixing can be carried out in any manner known to a technician. We may mention, for example, the use of mechanical mixing devices such as 45° three- or four-bladed impellers, Rushton turbines, marine propellers (whether single or multiple, combined or uncombined), or circulation loops equipped with centrifugal pumps and / or rotor-stator homogenizers.

[0036] The stirring speed is advantageously 10 to 1000 rpm, preferably 50 to 800 rpm.

[0037] In a particular embodiment, stirring is performed by a static mixer, which is a piping element comprising a helix or baffle or any other obstruction designed to increase turbulence, placed upstream of the reactor on a recirculation loop for reagents, catalyst, and recirculation flow.

[0038] Based on the total weight of mixture M1, the amount of alkyl (meth)acrylate is 50 to 97.899% by weight, preferably 60 to 90% by weight, and more preferably 65 to 85% by weight.

[0039] Alkyl methacrylates can be straight-chain, cyclic (substituted or unsubstituted), or branched. Preferably, the alkyl methacrylate is straight-chain, and the alkyl chain advantageously comprises 1 to 10, more preferably 1 to 8, and more preferably 1 to 4 carbons. Even more preferably, the alkyl group is methyl or ethyl. Even more preferably, the alkyl methacrylate is methyl methacrylate.

[0040] Based on the total weight of mixture M1, the amount of alkanolamine is 0.1 to 40% by weight, preferably 2 to 30% by weight, more preferably 5 to 25% by weight.

[0041] Alkylamines correspond to compounds containing both a hydroxyl group (-OH) and an amine functional group on the alkane backbone. The amine functional group can be a primary amine (-NH2), a secondary amine (-NHR1), or a tertiary amine (-NR1R2). Preferably, the amine functional group is a tertiary amine (-NR1R2). The alkane backbone is a hydrocarbon chain containing 1 to 10 carbon atoms.

[0042] The alkyl groups -R1 and -R2 of the tertiary amine are hydrocarbon chains that each independently contain 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. More preferably, -R1 and -R2 each have 1 carbon atom.

[0043] Based on the total weight of mixture M1, the amount of catalyst is 0.001 to 10% by weight, preferably 2 to 30% by weight, and preferably 0.01 to 5% by weight.

[0044] The amount of catalyst is advantageously 0.1 to 150 mmol per mol of alkanolamine, preferably 1 to 30 mmol, more preferably 1.1 to 25 mmol per mol of alkanolamine.

[0045] The catalyst is an organometallic derivative. The choice of catalyst depends on various criteria, such as the nature of the aminoalkyl methacrylate to be synthesized or the alcohol used. For example, the organometallic catalyst can be a derivative of tin, titanium, zirconium, or zinc. A non-limiting list of catalysts includes titanium tetraisopropoxide (TTIP) and zirconium tetraacetylacetone. Preferably, the catalyst is a tin derivative, more preferably dialkyltin oxide. Even more preferably, the catalyst is dibutyltin oxide (DBTO).

[0046] Adjust the amounts of the different compounds constituting mixture M1 so that they do not exceed 100% by weight.

[0047] In a preferred embodiment, the catalyst is in the form of a suspension S1, wherein 70% to 95% by weight of the catalyst is dissolved based on the total amount of catalyst in the suspension S1, and 5% to 30% by weight of the catalyst is in the form of particles suspended in the suspension S1. Preferably, more than 80% by weight and no more than 95% by weight, more preferably more than 85% by weight and no more than 95% by weight of the catalyst is dissolved in the suspension S1.

[0048] In the batch synthesis method (step 1 + step 2), the molar ratio between the alkyl methacrylate and the total amount of alkanolamine used is advantageously 1:5 to 5:1, preferably 1:2 to 2:1.

[0049] The solvent used in the method of the present invention is advantageously an inert solvent, i.e., a solvent that does not react with alkanolamines and alkyl (meth)acrylates, and is advantageously selected from saturated or unsaturated straight-chain, branched, or cyclic hydrocarbons containing 3 to 16 carbon atoms. Preferably, the solvent is selected from n-hexane, n-hexane isomers, and mixtures thereof.

[0050] Based on the total weight of mixture M1, the amount of solvent is 2 to 30% by weight, preferably 3 to 20% by weight, more preferably 4 to 15% by weight.

[0051] Step 2)

[0052] In the second step, mixture M1 is heated at a temperature T1 ranging from 40°C to 120°C, and the alkyl alcohols formed during the reaction are removed by azeotropic distillation. An azeotrope is formed between the solvent and the alkyl alcohols produced by the transesterification of (meth)acrylate with alkanolamines. By distilling mixture M1, the thermodynamic equilibrium shifts towards the formation of (meth)acrylate aminoalkyl esters. The distillation time ranges from 30 minutes to 720 minutes. During the distillation process, an additional amount of alkanolamine is continuously added.

[0053] The mixture M1 is heated at a temperature T1 of 40°C to 120°C, preferably 70°C to 100°C.

[0054] Azeotropic distillation is advantageously carried out for 30 to 720 minutes, preferably 240 to 500 minutes.

[0055] Based on the total amount of alkanolamines used in steps 1) and 2), the additional amount of alkanolamines added sequentially is 15 to 85% by weight, preferably 20 to 80% by weight.

[0056] The addition rate of at least one alkanolamine preferably corresponds to the evaporation rate of the alkyl alcohol.

[0057] In step 2)(ii), the alkanolamine is continuously added while the alkyl alcohol evaporates. The addition advantageously continues for 30 to 720 minutes. In other words, in step 2)(ii), the alkanolamine is added... at the same time Alkyl alcohols are distilled off.

[0058] In a preferred embodiment, the addition of alkanolamines is carried out in three stages:

[0059] (i) First stage: Add 10 to 40% by weight of the total alkanolamines added sequentially in step 2).

[0060] Continue for 10% to 40% of the total distillation time in step 2);

[0061] (ii) Second stage: Add 20 to 60% by weight of the total alkanolamines added sequentially in step 2.

[0062] Continue for 20% to 50% of the total distillation time in step 2);

[0063] (iii) Third stage: Add 10 to 25% by weight of the total alkanolamines added sequentially in step 2.

[0064] Continue for 10% to 30% of the total distillation time in step 2).

[0065] Advantageously, in this preferred embodiment, the addition rate of the alkanolamine will be adjusted by a technician such that the addition rate of the alkanolamine in the second stage (ii) is higher than that in the first stage (i) (second stage (ii) > first stage (i)), and the addition rate of the alkanolamine in the third stage (iii) is lower than that in the second stage (ii) (third stage (iii) < second stage (ii)).

[0066] Furthermore, the sum of the distillation times of the three stages (i) to (iii) equals the total distillation time of step 2 (the distillation time of stage (i) + stage (ii) + stage (iii) = 100% of the total distillation time).

[0067] In a specific implementation, an additional amount of catalyst is added continuously in step 2)(ii).

[0068] Based on the total amount of catalyst used in steps 1) and 2), the additional amount of catalyst added continuously is 1 to 80% by weight, preferably 30 to 50% by weight.

[0069] Additional catalysts may be added in solid form or as a suspension (such as suspension S1 as defined above) or in liquid form.

[0070] In step 2)(ii), the addition of the alkanolamine advantageously begins when mixture M1 reaches its boiling point. Preferably, in step 2)(ii), the alkanolamine is added when the alkyl alcohol begins to evaporate.

[0071] Step 3)

[0072] In step 3), aminoalkyl methacrylate is recovered by distillation of mixture M2.

[0073] Distillation can be carried out at atmospheric pressure or below. Preferred distillation is carried out at below atmospheric pressure.

[0074] When distillation is carried out at a pressure below atmospheric pressure, the pressure is advantageously from 1 to less than 1000 mbar absolute pressure (1 mbar = 100 Pa). The pressure is preferably less than 900 mbar absolute pressure, more preferably less than 800 mbar absolute pressure, more preferably less than 700 mbar absolute pressure, more preferably less than 600 mbar absolute pressure, more preferably less than 500 mbar absolute pressure, more preferably less than 400 mbar absolute pressure, more preferably less than 300 mbar absolute pressure, more preferably less than 200 mbar absolute pressure, more preferably less than 100 mbar absolute pressure, and even more preferably less than 50 mbar absolute pressure, and preferably greater than 1 mbar absolute pressure. Absolute pressure corresponds to pressure relative to zero pressure (vacuum).

[0075] The distillation time is advantageously from 30 minutes to 600 minutes, preferably from 60 minutes to 360 minutes.

[0076] To accelerate the distillation process, the mixture M2 can be advantageously heated at 60 to 120°C, preferably 80 to 100°C.

[0077] Optional steps

[0078] The batch synthesis method according to the invention may include additional optional steps. For example, after the (meth)acrylate aminoalkyl ester is recovered, it may be purified, for example, by distillation.

[0079] When using an organotin catalyst, the catalyst can be recycled as described in the applicant's patent application WO2019196048, or it can be recycled as described in the applicant's patent application CN117000313.

[0080] In a preferred embodiment, steps 1 to 3 of the intermittent method are repeated.

[0081] In this embodiment, the method advantageously includes recycling the catalyst.

[0082] In a specific implementation, at least one of the (meth)acrylate alkyl ester, alkanolamine, and solvent in the batch synthesis method is derived from a raw material containing recycled or biologically derived materials.

[0083] Another object of the present invention relates to aminoalkyl methacrylates and their salts obtained by the intermittent synthesis method according to the present invention.

[0084] Another object of the present invention relates to polymers obtained by polymerizing at least one aminoalkyl ester of (meth)acrylate obtained by the batch synthesis method according to the present invention.

[0085] The present invention and its advantages will be better illustrated by, but not limited to, the embodiments given below for illustrating the invention.

[0086] List of abbreviations:

[0087] DMAEA: 2-Dimethylaminoethyl acrylate

[0088] MA: Methyl acrylate

[0089] DMOH: Dimethylaminoethanol

[0090] Hx: Hexane

[0091] DBTO: Dibutyltin oxide

[0092] Ptz: Phenothiazine

[0093] GC-FID: Gas Chromatography Flame Ionization Detector

[0094] MeOH: Methanol

[0095] ICP-OES: Inductively Coupled Plasma Optical Emission Spectroscopy

[0096] Example

[0097] Example 1: Intermittent Synthesis of DMAEA - General Procedure

[0098] a) Preparation of mixture M1 (Step 1)

[0099] In a 250 mL three-necked round-bottom flask, add MA, DMOH, Hx, DBTO, and Ptz to form mixture M1. Stir reaction mixture M1 at 500 rpm.

[0100] A 50cm high column with an inner diameter of 20mm and fitted with a Dixon ring (3mm) is mounted on the central neck, and a cooling condenser containing -10°C ethylene glycol water is placed on top of the column.

[0101] The mixture M1 is heated at 110°C using a heating plate.

[0102] b) Prepare mixture M2 (Step 2)

[0103] Then, a certain amount of DMOH was continuously added to the reaction mixture using a metering pump for 4 hours.

[0104] By maintaining the temperature at the top of the column within the range of 48 to 53°C, the distillate is continuously collected at the top of the column. This temperature range indicates that the vapor composition is close to an azeotropic mixture Hx / MeOH.

[0105] The reflux rate control valve is used to collect distillate, control the reflux rate, and indirectly regulate the heating temperature.

[0106] For every 10 mL of distillate collected, 7 mL of Hx is reintroduced into the reaction medium to simulate the industrial process of Hx / MeOH phase separation and Hx reinjection.

[0107] The reaction continues until the temperature at the top of the column can no longer be kept below 53°C, indicating that the reaction is complete.

[0108] The reaction mixture was analyzed using the GC-FID method.

[0109] The GC Agilent 7820A is used with a 30m DB-WAX UI column with an inner diameter of 0.50μm.

[0110] Detection was performed using a flame ionization detector.

[0111] Five sample standards with different compositions, namely DMAEA, DMOH, MA, MeOH, and Hx, were injected to establish calibration curves.

[0112] The response factor obtained from DMAEA was applied to quantify the heavier components observed after a retention time of 16 minutes.

[0113] DMAEA conversion rate is calculated as follows:

[0114]

[0115] c) Recover DMAEA (Step 3)

[0116] The reaction mixture was then distilled under heating and vacuum pressure using the same apparatus as described above. DMAEA was collected when the temperature at the top of the column reached 78°C at an absolute pressure of 40 mbar to 5 mbar. 90% of the DMAEA in the mixture was recovered by distillation. The DMAEA fraction was weighed and analyzed using the GC-FID method. The residue below was collected and weighed.

[0117] According to Example 1 (E1) of the present invention, the amount of DMOH added in step 2)(ii) is 75% by weight.

[0118] Comparative Examples 2 to 4 (CE2 to CE4) were conducted in step 2)(ii) using amounts of DMOH that were outside the scope of the present invention.

[0119] Comparative Example 5 (CE5) was carried out in the same manner as Example 1, except that in step 2), an additional amount of DMOH was added all at once instead of being added continuously by distillation.

[0120] The components of steps 1) and 2) in different embodiments are listed in Table 1.

[0121]

[0122] Table 1. Amounts of raw materials used in steps 1 and 2 of batch methods with different compositions (E1 according to the present invention and comparative examples CE2 to CE5).

[0123] *DMOH is added all at once, rather than continuously through azeotropic distillation.

[0124] After distilling the DMAEA product, collect the residue below, adjust the amount of the initial feedstock with fresh feedstock, and use it for the second DMAEA reaction.

[0125] The batch process was repeated four times (hereinafter referred to as x.1 to x.4) under the same reaction conditions as the first reaction (hereinafter referred to as "x.0").

[0126] Assess the amounts of DMAEA, residual DMOH, heavy matter, and waste, as well as the conversion rate and reaction time for each reaction process.

[0127] The results are shown in Tables 2 to 6 below.

[0128] 1) Results of adding 75% by weight DMOH in step 2) using the intermittent method (E1.0 to E1.4) according to the present invention.

[0129]

[0130] Table 2. Results of the synthesis of DMAEA using the five-times batch reaction method according to the present invention (E1.0 to E1.4); 2) Results of the comparative batch method (CE2.0 to CE2.4) without the addition of DMOH in step 2).

[0131] Comparative Example 2 (CE2) CE2.0 CE2.1 CE2.2 CE2.3 CE2.4 DMAEA (weight %) 69.1 68.1 67.1 64.1 62.0 DMOH (wt%) 0.5 1.0 1.5 5.1 6.0 Heavy matter (wt%) 0.4 0.7 1.1 1.4 1.7 Reaction time (h) 7 7.5 8 8.5 9 Conversion rate (%) 98.8 97.6 96.3 90.8 88.9 Final waste (g) 6.1 6.9 7.8 10.7 11.8 Waste / DMAEA (% by weight / weight) 0.07 0.07 0.09 0.12 0.14

[0132] Table 3. Results of the synthesis of DMAEA using the five batch reaction methods without the addition of DMOH in step 2) (CE2.0 to CE2.4)

[0133] 3) Results of the comparative intermittent method (CE3.0 to CE3.4) in step 2) with the addition of 90 wt% DMOH.

[0134] Comparative Example 3 (CE3) CE3.0 CE3.1 CE3.2 CE3.3 CE3.4 DMAEA (weight %) 68.7 68.1 67.1 65.1 64.1 DMOH (wt%) 0.5 0.8 1.0 2.8 3.3 Heavy matter (wt%) 0.2 0.5 0.7 1.0 1.2 Reaction time (h) 9 7 8.5 9 9 Conversion rate (%) 98.9 98.1 97.4 94.5 93.5 Final waste (g) 5.9 6.5 6.9 8.4 9.0 Waste / DMAEA (% by weight / weight) 0.057 0.063 0.069 0.086 0.094

[0135] Table 4. Results of the synthesis of DMAEA by five batch reactions with 90 wt% DMOH added in step 2) (CE3.0 to CE3.4)

[0136] 4) Results of the comparative intermittent method (CE4.0 to CE4.4) in step 2) by adding 100% DMOH.

[0137] Comparative Example 4 (CE4) CE4.0 CE4.1 CE4.2 CE4.3 CE4.4 DMAEA (weight %) 68.9 68.1 67.1 64.6 63.1 DMOH (wt%) 0.5 0.9 1.3 4.0 4.6 Heavy matter (wt%) 0.3 0.6 0.9 1.2 1.5 Reaction time (h) 10 9 8.5 9 9 Conversion rate (%) 98.8 97.9 96.9 92.6 91.2 Final waste (g) 6.0 6.7 7.3 9.6 10.4 Waste / DMAEA (% by weight / weight) 0.058 0.065 0.073 0.099 0.110

[0138] Table 5. Results of the synthesis of DMAEA by five batch reactions with 100% DMOH added in step 2) (CE4.0 to CE4.4)

[0139] 5) Results of the comparative intermittent method (CE5.0 to CE5.4) in which 85% wt% DMOH was added in a single step in step 2).

[0140] Comparative Example 5 (CE5) CE5.0 CE5.1 CE5.2 CE5.3 CE5.4 DMAEA (weight %) 68.9 68.1 66.7 64.5 63.0 DMOH (wt%) 0.6 1.1 1.4 4.5 5.8 Heavy matter (wt%) 0.4 0.7 1.1 1.4 1.7 Reaction time (h) 7.1 7.8 7.9 8.4 8.8 Conversion rate (%) 98.7 97.5 96.4 916 89.3 Final waste (g) 6.1 6.9 7.7 103 11.7 Waste / DMAEA (% by weight / weight) 0.066 0.075 0.085 0.119 0.138

[0141] Table 6. Results of the synthesis of DMAEA using a five-stage batch reaction method with a single addition of DMOH in step 2) (CE5.0 to CE5.4)

[0142] The results show that, according to the present invention, the continuous addition of a specific amount of DMOH in step 2) allows the reaction to be carried out in a batch manner while maintaining a good conversion rate and DMAEA yield, and also results in a reduction in the amount of waste and heavy materials.

[0143] These tables show that when a specific amount of DMOH is added during the synthesis of (meth)acrylate aminoalkyl, and when a specific amount of DMOH is added continuously during the synthesis process, the synthesis is improved in terms of yield, catalyst recyclability, waste reduction due to the formation of less heavy material, and synthesis kinetics.

Claims

1. A batch synthesis method for (meth)acrylate aminoalkyl esters, comprising the following sequential steps: 1) Prepare a mixture M1 comprising the following: (i) 50 to 97.899% by weight of at least one alkyl (meth)acrylate; (ii) 0.1 to 40% by weight of at least one alkanolamine; (iii) at least one catalyst, ranging from 0.001 to 10% by weight; (iv) 2 to 30% by weight of at least one solvent; Based on the total weight of mixture M1; 2) Mixture M2 is prepared by the following method: (i) The mixture M1 is heated to a temperature T1 of 40°C to 120°C, and the alkyl alcohols formed during the reaction are removed by azeotropic distillation; the azeotropic distillation is carried out at T1 for 30 to 720 min. (ii) During the azeotropic distillation process, at least one alkanolamine is further added continuously in an amount of 15 to 85% by weight based on the total amount of alkanolamines used in steps 1) and 2). 3) Recover (meth)acrylate aminoalkyl esters by distilling mixture M2.

2. The batch synthesis method according to claim 1, wherein the alkyl methacrylate is methyl methacrylate.

3. The batch synthesis method according to claim 1 or 2, wherein the amine of the alkanolamine is a tertiary amine -NR1R2, wherein R1 and R2 are alkyl groups having 1 to 8 carbon atoms independently.

4. The batch synthesis method according to any one of claims 1 to 3, wherein the alkanolamine is dimethylaminoethanol.

5. The batch synthesis method according to any one of claims 1 to 4, wherein the catalyst is in the form of a suspension S1, wherein, Based on the total amount of catalyst in the suspension S1, 70% to 95% by weight of the catalyst is dissolved, and 5% to 30% by weight of the catalyst is in the form of particles suspended in the suspension S1.

6. The batch synthesis method according to any one of claims 1 to 5, wherein the amount of alkanolamine added in step 2)(ii) is 20 to 80% by weight based on the total weight of the alkanolamines used in steps 1) and 2).

7. The batch synthesis method according to any one of claims 1 to 6, wherein in step 2)(ii), an alkanolamine is continuously added while the alkyl alcohol is evaporated, the addition lasting for 30 to 720 min.

8. The batch synthesis method according to any one of claims 1 to 7, wherein the addition of at least one alkanolamine in step 2) is divided into three stages: (i) First stage: Add 10 to 40% by weight of the total alkanolamines added sequentially in step 2). Continue for 10% to 40% of the total distillation time in step 2); (ii) Second stage: Add 20 to 60% by weight of the total alkanolamines added sequentially in step 2. Continue for 20% to 50% of the total distillation time in step 2); (iii) Third stage: Add 10 to 25% by weight of the total alkanolamines added continuously in step 2, for 10% to 30% of the total distillation time of step 2).

9. The batch synthesis method according to any one of claims 1 to 8, wherein an additional amount of catalyst is continuously added in step 2)(ii).

10. The batch synthesis method according to claim 9, wherein the catalyst is continuously added in an amount of 1 to 80% by weight based on the total weight of the catalyst used in steps 1) and 2).

11. The batch synthesis method according to any one of claims 1 to 10, wherein step 2)(ii) is started when the mixture M1 reaches its boiling point.

12. The batch synthesis method according to any one of claims 1 to 11, wherein step 2)(ii) begins when the alkyl alcohol begins to evaporate.

13. The intermittent synthesis method according to any one of claims 1 to 12, wherein steps 1 to 3 are repeated.

14. The batch synthesis method according to any one of claims 1 to 13, wherein steps 1 to 3 are repeated and wherein the batch synthesis method comprises recycling the catalyst.

15. The batch synthesis method according to any one of claims 1 to 13, wherein at least one of the alkyl methacrylate, alkanolamine and solvent is derived from a raw material comprising recycled or biologically derived material.

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