阅读说明：本技术 用于生产（甲基）丙烯酸2-二甲氨基乙酯的方法 (Process for producing 2-dimethylaminoethyl (meth) acrylate ) 是由 塞德里克·法维罗 约翰·基弗 凌静 于 2018-04-12 设计创作，主要内容包括：一种以多级分批反应生产(甲基)丙烯酸2-二甲氨基乙酯的方法,包括使催化剂(DBTO)再循环到后续反应中、向再循环的催化剂中添加一定量的新鲜催化剂、在后续反应中使用所述催化剂,并且其中由于共沸蒸馏而引起的体积减小通过连续添加包含(甲基)丙烯酸甲酯和二甲氨基乙醇的组合物进行补偿,从而在反应期间保持反应器中的体积恒定。(A process for producing 2-dimethylaminoethyl (meth) acrylate in a multi-stage batch reaction, comprising recycling catalyst (DBTO) to a subsequent reaction, adding an amount of fresh catalyst to the recycled catalyst, using said catalyst in the subsequent reaction, and wherein the volume reduction due to azeotropic distillation is compensated for by continuous addition of a composition comprising methyl (meth) acrylate and dimethylaminoethanol, thereby keeping the volume in the reactor constant during the reaction.)

1. 2-dimethylaminoethyl (meth) acrylate obtained according to a process comprising at least two consecutive batch reactions, wherein in each batch reaction methyl (meth) acrylate, dimethylaminoethanol, a solvent and dibutyltin oxide as a catalyst are added as initial feeds to a stirred reactor equipped with a distillation column, wherein azeotropic distillation is carried out continuously during the reaction, wherein the decrease in volume due to said azeotropic distillation is compensated for by the continuous addition of a composition comprising methyl (meth) acrylate and dimethylaminoethanol, which may also comprise dibutyltin oxide, so as to keep the volume in said reactor constant, said process comprising:

-a first batch reaction in which the dibutyltin oxide used as catalyst is fresh dibutyltin oxide;

-a separation step wherein dibutyltin oxide from the first batch reaction is recovered from the reaction mixture of the first batch reaction, and the dibutyltin oxide from the first batch reaction constitutes recycled dibutyltin oxide;

-at least a second batch reaction, wherein at least 65% by weight of the recycled dibutyltin oxide is used as catalyst for the second batch reaction together with fresh dibutyltin oxide:

wherein the amount of fresh dibutyltin oxide is from 0.1 to 35 wt% based on the recycled dibutyltin oxide from the first batch reaction,

wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide added in the initial charge is from 220/1 to 80/20,

omicron, wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide, if dibutyltin oxide is included, is from 100/0 to 0/100 in the composition continuously added to compensate for the azeotropic distillation.

2. 2-dimethylaminoethyl (meth) acrylate according to claim 1, wherein the process comprises at least one subsequent batch reaction in which at least 65% by weight of the recycled dibutyltin oxide from the previous reaction is used as catalyst for the reaction together with fresh dibutyltin oxide:

wherein the amount of fresh dibutyltin oxide is from 0.1 to 35 wt% based on the recycled dibutyltin oxide from the previous reaction,

wherein the mass ratio of recycled dibutyltin oxide from the previous reaction added in the initial charge to fresh dibutyltin oxide is from 220/1 to 80/20,

omicron wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide from the previous reaction, in the case where dibutyltin oxide is included, is from 100/0 to 0/100 in the composition continuously added to compensate for the azeotropic distillation.

3. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein the process comprises a total of at least 3, preferably 4, more preferably 5, even more preferably 6, even more preferably 7, even more preferably 8, even more preferably 9, even more preferably 10, up to 20 batch reactions, wherein in each batch reaction the recycled dibutyltin oxide from the previous reaction is used as catalyst in combination with fresh dibutyltin oxide according to claim 1.

4. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein the solvent is a linear, cyclic or branched alkane from C6 to C12.

5. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein the continuous batch reaction of the process is carried out in the same reactor.

6. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein the composition continuously added during the reaction to compensate for the volume reduction due to the azeotropic distillation comprises methyl (meth) acrylate, dimethylaminoethanol, dibutyltin oxide and a solvent.

7. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein the composition continuously added during the reaction to compensate for the volume reduction due to the azeotropic distillation is the same as the composition initially added to the reactor before the start of the reaction.

8. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein at least 80 wt%, preferably at least 85 wt%, more preferably at least 90 wt% of the recycled dibutyltin oxide from the preceding reaction is recovered in the second and/or subsequent batch reaction together with fresh dibutyltin oxide as catalyst for the subsequent reaction.

9. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein the amount of fresh dibutyltin oxide in each subsequent reaction is from 0.1 to 20 wt%, preferably from 0.5 to 15 wt%, even more preferably from 0.5 to 10 wt%, based on the recycled dibutyltin oxide.

10. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein in each subsequent batch reaction the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide added in the initial charge to each subsequent reaction is from 97/3 to 85/15, preferably from 95/5 to 87/13, even more preferably from 90/10, even more preferably from 99/1.

11. 2-dimethylaminoethyl (meth) acrylate according to any one of the preceding claims, wherein in the composition continuously added to compensate for the azeotropic distillation to keep the volume in the reactor constant, the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide, in the case where dibutyltin oxide is included, is from 95/5 to 5/95, preferably from 90/10 to 10/90.

12. A 2-dimethylaminoethyl (meth) acrylate mixture recovered after a separation step from a reaction mixture obtained according to the process comprising at least two consecutive batch reactions, wherein in each batch reaction methyl (meth) acrylate, dimethylaminoethanol, a solvent and dibutyltin oxide as a catalyst are added as initial feeds to a stirred reactor equipped with a distillation column, wherein azeotropic distillation is carried out continuously during the reaction, wherein the decrease in volume due to said azeotropic distillation is compensated for by the continuous addition of a composition comprising methyl (meth) acrylate and dimethylaminoethanol, which may also comprise dibutyltin oxide, so as to keep the volume in said reactor constant, said process comprising:

-a first batch reaction in which the dibutyltin oxide used as catalyst is fresh dibutyltin oxide;

-a separation step wherein dibutyltin oxide from the first batch reaction is recovered from the reaction mixture of the first batch reaction, and the dibutyltin oxide from the first batch reaction constitutes recycled dibutyltin oxide;

-at least a second batch reaction, wherein at least 65% by weight of the recycled dibutyltin oxide is used as catalyst for the second batch reaction together with fresh dibutyltin oxide:

wherein the amount of fresh dibutyltin oxide is from 0.1 to 35 wt% based on the recycled dibutyltin oxide from the first batch reaction,

wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide added in the initial charge is from 220/1 to 80/20,

omicron, wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide, if dibutyltin oxide is included, is from 100/0 to 0/100 in the composition continuously added to compensate for the azeotropic distillation.

13. The 2-dimethylaminoethyl (meth) acrylate mixture according to claim 12, wherein said process comprises at least one subsequent batch reaction wherein at least 65% by weight of said recycled dibutyltin oxide from the previous reaction is used as catalyst for said reaction together with fresh dibutyltin oxide:

wherein the amount of fresh dibutyltin oxide is from 0.1 to 35 wt% based on the recycled dibutyltin oxide from the previous reaction,

wherein the mass ratio of recycled dibutyltin oxide from the previous reaction added in the initial charge to fresh dibutyltin oxide is from 220/1 to 80/20,

omicron wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide from the previous reaction, in the case where dibutyltin oxide is included, is from 100/0 to 0/100 in the composition continuously added to compensate for the azeotropic distillation.

14. 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein the process comprises a total of at least 3, preferably 4, more preferably 5, even more preferably 6, even more preferably 7, even more preferably 8, even more preferably 9, even more preferably 10, up to 20 batch reactions, wherein in each batch reaction the recycled dibutyltin oxide from the previous reaction is used as catalyst in combination with fresh dibutyltin oxide according to claim 12.

15. The 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein the solvent is a C6 to C12 linear, cyclic or branched alkane.

16. The 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein the continuous batch reaction of the process is carried out in the same reactor.

17. The 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein the composition continuously added during the reaction to compensate for volume reduction due to the azeotropic distillation comprises methyl (meth) acrylate, dimethylaminoethanol, dibutyltin oxide and a solvent.

18. The 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein the composition of the composition continuously added during the reaction to compensate for the volume reduction due to the azeotropic distillation is the same as the composition initially added to the reactor before the reaction starts.

19. 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein at least 80 wt%, preferably at least 85 wt%, more preferably at least 90 wt% of the recycled dibutyltin oxide from the preceding reaction is recovered in the second and/or subsequent batch reaction as catalyst for the subsequent reaction together with fresh dibutyltin oxide.

20. 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein the amount of fresh dibutyltin oxide in each subsequent reaction is from 0.1 to 20 wt%, preferably from 0.5 to 15 wt%, even more preferably from 0.5 to 10 wt%, based on the recycled dibutyltin oxide.

21. 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein in each subsequent batch reaction the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide added in the initial charge to each subsequent reaction is from 97/3 to 85/15, preferably from 95/5 to 87/13, even more preferably from 90/10, even more preferably from 99/1.

22. 2-dimethylaminoethyl (meth) acrylate mixture according to any one of the preceding claims, wherein in the composition continuously added to compensate for the azeotropic distillation to keep the volume in the reactor constant, the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide, if any, is from 95/5 to 5/95, preferably from 90/10 to 10/90.

23. A quaternized form of 2-dimethylaminoethyl (meth) acrylate according to any one of claims 1-11 or a mixture of 2-dimethylaminoethyl (meth) acrylates according to any one of claims 12-22.

24. A polymer prepared with the quaternized form of 2-dimethylaminoethyl (meth) acrylate of claim 23.

25. A polymer according to claim 24, obtained by polymerizing the quaternized form of 2-dimethylaminoethyl (meth) acrylate according to claim 23 and at least one monomer selected from the list of:

-nonionic monomers: acrylamide, methacrylamide, N-dimethylacrylamide, N-diethylacrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, methacrylic acid esters of polyethylene glycol, diacetone acrylamide, N-isopropylacrylamide, 2-hydroxyethyl acrylate, 2, 3-dihydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2, 3-dihydroxypropyl methacrylate, N-tert-butylacrylamide,

-anionic monomers: non-salified, partially salified or fully salified acrylic acid, 2-acrylamido-2-methylpropanesulfonic Acid (ATBS), methacrylic acid, itaconic acid, maleic acid, allyl sulfonate,

-a cationic monomer: diallyldimethylammonium chloride (DADMAC), acrylamido dialkylaminopropyl, methacrylamido dialkylaminopropyl, and acidified salts or quaternary ammonium salts thereof.

-a structuring agent: polyethylenically unsaturated monomers having at least two unsaturated functional groups (e.g., vinyl, allyl, acrylic and epoxy functional groups), such as Methylene Bis Acrylamide (MBA), triallylamine, tetraallylammonium chloride, or macroinitiators such as polyperoxides, polyazo compounds and transfer polymerization agents such as polythiol polymers.

26. Use of a polymer according to claim 24 or 25 in water treatment, sludge dewatering, paper making processes, agriculture, cosmetic and cleaning compositions, textile processes, oil and gas recovery processes such as enhanced oil recovery, fracturing, mining operations such as tailings treatment.

Technical Field

The invention relates to a process for the production of 2-dimethylaminoethyl (meth) acrylate (also known as DMAE (M) A or (M)

) The method of (1).

Background

2-dimethylaminoethyl (meth) acrylate monomers are typically quaternized, for example with methyl chloride, dialkyl sulfate or benzyl chloride, and then polymerized to produce cationic polymers. These polymers are used in many industries such as water treatment, paper making, home and personal care, tertiary oil recovery.

It is known to catalyze transesterification reactions with organotin compounds. Among the (meth) acrylic esters of interest, 2-dimethylaminoethyl (meth) acrylate is obtained by transesterification of an alkyl (meth) acrylate and dimethylaminoethanol using a tin oxide derivative (e.g., dibutyltin oxide (DBTO)) as a catalyst. The role of the catalyst is to shift the equilibrium to produce more 2-dimethylaminoethyl (meth) acrylate and to reduce impurity formation.

The alkyl (meth) acrylate may be methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate. Methyl (meth) acrylate is generally preferred.

It is also known that other metal alkoxides may be used as transesterification catalysts, such as aluminum (III) isopropoxide, or titanium (IV) acid tetraalkoxides, such as described in US 8,067,637 or CN 105330556. Acetylacetonate derivatives are also used as catalysts, for example the metal complexes zirconium acetylacetonate, aluminum acetylacetonate, zinc acetylacetonate, iron acetylacetonate, for example as described in US 7,071,351 or WO 2001/157645. DBTO is a particularly advantageous catalyst because it is very active at low dosages, can be recycled many times and minimizes impurity formation, as opposed to titanate derivative catalysts which require stoichiometric amounts of catalyst associated with the starting materials.

Despite such advantages, DBTO tends to deactivate upon recycling and requires periodic replacement, which is expensive and generates toxic waste that is difficult to manage and dispose of.

When DBTO begins to deactivate, the reaction product contains more impurities. Generally, in the reaction of methyl (meth) acrylate and dimethylaminoethanol using DBTO as a catalyst, there are impurities produced as by-products, which degrade the quality of 2-dimethylaminoethyl (meth) acrylate. These impurities are Michael adducts of methanol or dimethylaminoethanol reacted with methyl (meth) acrylate, dimethylaminoethyl (meth) acrylate or (meth) acrylic acid.

In order to limit the formation of impurities such as Michael adducts formed from low molecular weight alcohols (methanol), it is known to conduct the reaction in a solvent. This enables elimination of low molecular weight alcohols during continuous azeotropic distillation. A disadvantage of this process is that the reduction in volume in the reactor makes the process less efficient.

At the end of the reaction, if the catalyst activity of the catalyst is sufficient to limit the formation of impurities, the catalyst is separated from the reaction mixture and recycled.

Typically, in the first reaction, fresh DBTO is used as catalyst. After this reaction, 100% of the DBTO recovered from the first reaction was recycled to the second reaction. After the second reaction, 100% of the DBTO recovered from the second reaction was recycled to the third reaction. But the DBTO recovered in the third reaction does not have sufficient catalytic activity to be used in the fourth reaction. In other words, if the DBTO is used in the fourth reaction, the quality of 2-dimethylaminoethyl (meth) acrylate is low because it contains a large amount of impurities.

Disclosure of Invention

The problem to be solved by the present invention is to improve the efficiency of the process for producing 2-dimethylaminoethyl (meth) acrylate and the quality of the resulting monomers.

It has been unexpectedly found that this can be accomplished by more efficient use of the reactor volume and more efficient use of the catalyst. The present invention is based on two principles. The first principle is to continuously add a composition comprising methyl (meth) acrylate, dimethylaminoethanol to compensate for the volume reduction due to azeotropic distillation and removal of low molecular weight alcohols. The second principle is to add a portion of fresh DBTO in addition to recycled DBTO in at least a subsequent batch reaction.

The present invention provides a process for producing 2-dimethylaminoethyl (meth) acrylate, which comprises at least two consecutive batch reactions, wherein in each batch reaction, methyl (meth) acrylate, dimethylaminoethanol, a solvent and dibutyltin oxide as a catalyst are added as initial feeds to a stirred reactor equipped with a distillation column, wherein azeotropic distillation is continuously carried out during the reaction, wherein the volume reduction due to said azeotropic distillation is compensated for by continuously adding a composition comprising methyl (meth) acrylate and dimethylaminoethanol, which may also comprise dibutyltin oxide, so that the volume in the reactor remains constant, said process comprising:

-a first batch reaction in which the dibutyltin oxide used as catalyst is fresh dibutyltin oxide;

-a separation step, wherein dibutyltin oxide from the first batch reaction is recovered from the reaction mixture of the first batch reaction, and said dibutyltin oxide from the first batch reaction constitutes recycled dibutyltin oxide;

-at least a second batch reaction, wherein at least 65% by weight of the recirculated dibutyltin oxide is used as catalyst for the second batch reaction together with fresh dibutyltin oxide:

o wherein the amount of fresh dibutyltin oxide, based on the recycled dibutyltin oxide from the first batch reaction, is from 0.1 to 35% by weight,

o wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide added in the initial charge is from 220/1 to 80/20,

o a composition wherein the mass ratio of the recycled dibutyltin oxide to the fresh dibutyltin oxide, in the case where dibutyltin oxide is contained, is from 100/0 to 0/100, wherein the composition is continuously added to compensate for azeotropic distillation.

By definition, fresh dibutyltin oxide is meant dibutyltin oxide which was first used for the reaction. In other words, fresh dibutyltin oxide was not recovered from the previous reaction for producing 2-dimethylaminoethyl (meth) acrylate. The term novel dibutyltin oxide is also used in the present invention and has the same meaning as fresh dibutyltin oxide.

In a preferred embodiment, the process of the invention comprises at least one subsequent batch reaction in which at least 65% by weight of the recirculated dibutyltin oxide from the preceding reaction is used as catalyst for the reaction together with fresh dibutyltin oxide:

o wherein the amount of fresh dibutyltin oxide, based on the recycled dibutyltin oxide from the previous reaction, is from 0.1 to 35% by weight,

o wherein the mass ratio of recycled dibutyltin oxide from the previous reaction to fresh dibutyltin oxide added in the initial charge is from 220/1 to 80/20,

o a composition wherein the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide from the previous reaction, in the case where dibutyltin oxide is contained, is from 100/0 to 0/100, wherein the composition is continuously added to compensate for azeotropic distillation.

The process of the present invention is a multi-stage batch reaction comprising recycling catalyst (DBTO) to a subsequent reaction, adding an amount of fresh or fresh catalyst to the recycled catalyst, and using the catalyst in a subsequent reaction.

The continuous addition of the composition comprising methyl (meth) acrylate and dimethylaminoethanol during the reaction enables the use of the maximum volume of the reactor, which is advantageous in terms of productivity. The composition may also contain dibutyltin oxide, which is preferred.

The combination of this maximum use of reactor volume, the recycle of DBTO and the addition of a specific proportion of fresh DBTO according to the invention makes it possible to improve the efficiency of the process for the production of 2-dimethylaminoethyl (meth) acrylate and to improve the quality of this monomer. Since 2-dimethylaminoethyl (meth) acrylate contains less impurities, its quality is better. The monomer quality was also more consistent in subsequent batches, since the catalyst activity remained constant at the optimum concentration for all batches. Another advantage of the process of the invention is that the overall consumption of catalyst per batch is reduced and therefore the overall amount of waste generated per batch is reduced.

In a preferred embodiment of the present invention, the process of the present invention comprises a total of at least 3, preferably 4, more preferably 5, even more preferably 6, even more preferably 7, even more preferably 8, even more preferably 9, even more preferably 10, up to 20 batch reactions, wherein according to the present invention recycled dibutyltin oxide from a previous reaction is used as catalyst in combination with fresh dibutyltin oxide.

In other words, this means that after the first reaction involving the process of the invention using only fresh catalyst, the process of the invention comprises at least 2, preferably 3, more preferably 4, even more preferably 5, even more preferably 6, even more preferably 7, even more preferably 8, even more preferably 9, up to 19 batch reactions, wherein according to the invention recycled dibutyltin oxide from the previous reaction is used as catalyst in combination with fresh dibutyltin oxide.

The reaction according to the invention is carried out in a stirred reactor equipped with a distillation column and a temperature-raising device. Typically, a solvent, methyl (meth) acrylate, dimethylaminoethanol, and dibutyltin oxide (DBTO) are added to the reactor. The reaction is initiated at elevated temperatures, as is known in the art. Methanol produced by the reaction is continuously evaporated together with some solvent and some (meth) acrylic ester and introduced into a distillation column. Preferably, the recovered solvent is recycled after separation from the alcohol and the (meth) acrylate.

The solvent used in the process of the invention is preferably an inert solvent and is typically a linear, cyclic or branched alkane of C6 to C12. The preferred solvent is hexane which forms an azeotrope with low molecular weight alcohols, especially with methanol.

According to the invention, the reduction in volume due to the evaporation of these products is continuously compensated by the continuous addition of equal volumes of a composition comprising methyl (meth) acrylate and dimethylaminoethanol. In a preferred embodiment, the composition further comprises dibutyltin oxide and a solvent. In a more preferred embodiment, the composition is the same as the composition initially added to the reactor prior to the start of the reaction.

The person skilled in the art knows how to carry out this reaction and can refer to document US 2012/0123148. The process of the present invention does not require a specific additional means to carry out the reaction to obtain 2-dimethylaminoethyl (meth) acrylate by transesterification of methyl (meth) acrylate and dimethylaminoethanol using dibutyltin oxide (DBTO) as a catalyst. The chemical ratios, temperatures and other parameters of the reaction are well known.

At the end of each batch reaction, 2-dimethylaminoethyl (meth) acrylate is recovered from the reaction mixture and purified, typically by distillation. DBTO is also recovered and recycled as described in the present invention. The skilled person knows how to perform these processes.

In a preferred embodiment, the reactions of the process of the invention are carried out in the same reactor, but may also be carried out in different reactors.

In a preferred embodiment, at least 80% by weight, preferably at least 85% by weight, more preferably at least 90% by weight of the recycled dibutyltin oxide recovered from the previous reaction is used as catalyst for the subsequent reaction together with fresh dibutyltin oxide in the second and/or subsequent batch reaction according to the invention.

In a preferred embodiment, the amount of fresh dibutyltin oxide in each subsequent reaction is from 0.1 to 20% by weight, preferably from 0.5 to 15% by weight, even more preferably from 0.5 to 10% by weight, based on the dibutyltin oxide recycled.

In a preferred embodiment, the mass ratio of recycled dibutyltin oxide to fresh dibutyltin oxide added in the initial charge for each subsequent reaction is from 97/3 to 85/15, preferably from 95/5 to 87/13, even more preferably from 90/10, even more preferably from 99/1.

In a preferred embodiment, in each subsequent reaction, in the case of dibutyltin oxide, the mass ratio of dibutyltin oxide recycled to fresh dibutyltin oxide is from 95/5 to 5/95, preferably from 90/10 to 10/90, in the composition which is added continuously to compensate for the azeotropic distillation and thus to keep the volume in the reactor constant.

In a preferred embodiment, the mass ratio of dibutyltin oxide recycled to dibutyltin oxide fresh is the same for the dibutyltin oxide added in the initial charge and the composition continuously added to compensate for the azeotropic distillation for each subsequent reaction. In this case, the preferred mass ratio is preferably 97/3 to 85/15, preferably 95/5 to 87/13, even more preferably 90/10, even more preferably 99/1.

The invention also provides 2-dimethylaminoethyl (meth) acrylate obtained according to the process of the invention. The monomeric 2-dimethylaminoethyl (meth) acrylate obtained is of better quality as it contains less impurities. The monomer quality with increasing batch is also improved as it is more uniform compared to a process without adding fresh catalyst and without compensating for the volume reduction (quality decreases significantly with increasing batch). This is because the process of the invention enables the action of the catalyst to be more uniform as the batch increases.

The present invention also provides a 2-dimethylaminoethyl (meth) acrylate mixture recovered from the reaction mixture obtained according to the process of the present invention after the separation step. The 2-dimethylaminoethyl (meth) acrylate mixture contains fewer impurities and has better quality.

The present invention also provides quaternized forms of the 2-dimethylaminoethyl (meth) acrylate of the invention. Quaternization is carried out, for example, with dimethyl sulfate, diethyl sulfate, benzyl chloride or methyl chloride or mixtures thereof, and preferably with methyl chloride to convert tertiary amines to quaternary amines.

The present invention also provides polymers prepared with quaternized forms of the 2-dimethylaminoethyl (meth) acrylate of the present invention. Any polymerization method may be used, such as gel polymerization, liquid phase polymerization, or emulsion polymerization. The polymer may be obtained in any form, e.g. powder, emulsion, dispersion, solution. The polymers of the invention are preferably water soluble, but may also be water swellable.

Additional monomers may be used in combination with quaternized forms of 2-dimethylaminoethyl (meth) acrylate to produce the polymers of the present invention. These monomers may be selected from the following list:

-nonionic monomers: acrylamide, methacrylamide, N-dimethylacrylamide, N-diethylacrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, methacrylic acid esters of polyethylene glycol, diacetone acrylamide, N-isopropylacrylamide, 2-hydroxyethyl acrylate, 2, 3-dihydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2, 3-dihydroxypropyl methacrylate, N-tert-butylacrylamide,

-anionic monomers: non-salified, partially salified or fully salified acrylic acid, 2-acrylamido-2-methylpropanesulfonic Acid (ATBS), methacrylic acid, itaconic acid, maleic acid, allyl sulfonate,

-a cationic monomer: diallyldimethylammonium chloride (DADMAC), acrylamido dialkylaminopropyl, methacrylamido dialkylaminopropyl, and acidified salts or quaternary ammonium salts thereof.

-a structuring agent: polyethylenically unsaturated monomers having at least two unsaturated functional groups, such as vinyl, allyl, acrylic and epoxy functional groups, and mention may be made, for example, of Methylene Bisacrylamide (MBA), triallylamine, tetraallylammonium chloride, or macroinitiators such as polyperoxides, polyazo compounds and transfer polymerization agents such as polythiol polymers.

The polymer according to the present invention is not limited in molecular weight. The polymer preferably has a weight average molecular weight of from 5,000g/mol to 100,000g/mol, or a weight average molecular weight of from 100,000g/mol to 1,000,000g/mol, or a weight average molecular weight of from 1,000,000g/mol to 30,000,000 g/mol. The weight average molecular weight was measured by Gel Permeation Chromatography (GPC).

The invention also provides the use of the polymers of the invention in water treatment, sludge dewatering, paper making processes, agriculture, cosmetic and cleaning compositions, textile processes, oil and gas recovery processes such as enhanced oil recovery, fracturing, mining operations such as tailings treatment.

Detailed Description

The present invention will now be illustrated in more detail by the following examples.