2-DIMETHYLAMINOETHYL ACRYLATE POLYMERS AND THEIR PREPARATION PROCESS

Abstract

The present invention relates to a water-soluble polymer obtained by polymerization of at least one 2-dimethylaminoethyl acrylate monomer and / or its salts, in the presence of at least one tocopherol and / or its derivatives, or of a tocotrienol and / or its derivatives, and its uses.

Description

Title of the invention: 2-DIMETHYLAMINOETHYL ACRYLATE POLYMERS AND PROCESS FOR PREPARING THE SAME PREPARATION TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a water-soluble polymer obtained from a composition comprising at least one 2-dimethylaminoethyl acrylate monomer and / or its salts combined with a tocopherol and / or its derivatives, or a tocotrienol and / or its derivatives, and its uses. TECHNOLOGICAL BACKGROUND

[0002] 2-Dimethylaminoethyl acrylate is a well-known monomer used to produce polymers used in many industries, such as water treatment, papermaking, personal care and hygiene products or the oil & gas industry such as enhanced oil recovery, hydraulic fracturing, water inflow reduction and others.

[0003] During long periods of storage, or long-distance transport, these monomers are subject to degradation due to Cope elimination. Cope elimination is a periplanar syn elimination during which six electrons form in a five-membered cycle according to the following [Fig.l]:

[0004] [Chem.l] Figure 1

[0005] Naturally occurring oxygen, which is required to activate a polymerization inhibitor, such as hydroquinone monomethyl ether (MeHQ), during storage of said monomers can react with the tertiary amine and form an amine oxide. The amine oxide is cleavable by a thermally induced mechanism into vinyl acrylate and hydroxydimethylamine in the case of 2-dimethylaminoethyl acrylate monomer.

[0006] Cope elimination is a common phenomenon, which leads to the formation of a significant amount of vinyl acrylate when said monomers are stored for a long period. Vinyl acrylate can also be formed during the synthesis of said monomers.

[0007] In some industries, for example in the hydraulic fracturing industry or in the paper industry, there is a need for a very high molecular weight and completely linear polymer, for example as a friction reducer or as a retention agent for paper. This impurity creates a covalent bond between two 2-dimethylaminoethyl acrylate monomers and, when preparing polymers from monomers comprising vinyl acrylate, their performance is considerably reduced.

[0008] US Document No. 10,343,980 describes the preparation of N,N-(di)alkylaminoalkyl(meth)acrylamide or N,N-(di)alkylaminoalkyl (meth)acrylate and their quaternary ammonium salt by controlling the amount of dioxygen present during the synthesis of said monomers and therefore the amount of vinyl acrylate present during the polymerization.

[0009] The control of the operating conditions of the processes described above must be very strict, and additional processing steps, such as purification steps, may lead to the formation of various by-products, most of which must not remain in the final product. These additional steps inevitably lead to known disadvantages, e.g., yield losses, higher maintenance and operating costs and, more importantly, they do not prevent the formation of additional vinyl acrylate impurities once the monomers are stored due to the presence of dioxygen, during storage, which is necessary for the activation of polymerization inhibitors such as MeHQ, as described in the publication "The role of hydroquinone monomethyl ether in the stabilization of acrylic acid", Holger Becker and Herbert Vogel, Chem. Eng.Technol. 2006, 29, No.10, 1227-1231. .

[0010] The applicant has surprisingly discovered that by combining 2-dimethylaminoethyl acrylate monomers and / or their salts with at least one tocopherol and / or its derivatives, or one tocotrienol and / or its derivatives, the formation of vinyl acrylate is inhibited and the polymers resulting from said monomers and / or their salts exhibit better performance.

[0011] The preparation of the polymers of the invention is part of a general principle of improving product performance. The improved performance of the polymers of the invention allows for a reduction in the quantity of product required for application and reduces water consumption, which implicitly contributes to reducing greenhouse gas emissions such as CO2. Summary of the invention

[0012] The present invention relates to a water-soluble polymer obtained by polymerization of at least one 2-dimethylaminoethyl acrylate monomer and / or its salts in the presence of at least one tocopherol and / or its derivatives, or of a tocotrienol and / or its derivatives.

[0013] The invention also relates to the process for preparing such a water-soluble polymer, comprising the polymerization of at least one 2-dimethylaminoethyl acrylate monomer and / or its salts in the presence of at least one tocopherol and / or its derivatives, or of a tocotrienol and / or its derivatives.

[0014] The invention also relates to a method for inhibiting the formation of vinyl acrylate resulting from a reaction between at least one 2-dimethylaminoethyl acrylate monomer and / or its salts and oxygen, comprising mixing said 2-dimethylaminoethyl acrylate monomer and / or its salts with a tocopherol and / or its derivatives, or a tocotrienol and / or its derivatives.

[0015] The present invention also relates to a composition comprising: - from 1 to 99.9999% by weight of at least one monomer of 2-dimethylaminoethyl acrylate and / or its salts; - from 1 to 10,000 ppm of at least one tocopherol and / or its derivatives, or one tocotrienol and / or its derivatives, based on the amount of 2-dimethylaminoethyl acrylate monomer and / or its salts; - optionally at least one additive chosen from biocides, polymerization inhibitors, moisture absorbers, color stabilizers.

[0016] The amount of 2-dimethylaminoethyl acrylate monomer and / or its salts, and optionally of the additive, is expressed relative to the total weight of the composition. The amount of tocopherol and / or its derivatives, or tocotrienol and / or its derivatives, is expressed relative to the amount of 2-dimethylaminoethyl acrylate monomer and / or its salts.

[0017] A person skilled in the art knows how to adjust the quantities of the constituents of the composition, in particular the quantities of 2-dimethylaminoethyl acrylate monomer and / or its salts, of tocopherol and / or its derivatives, or of tocotrienol and / or its derivatives, and optionally of the additive, to reach 100% by weight.

[0018] The present invention also relates to the use of said water-soluble polymer for water treatment, sludge dewatering, a paper manufacturing process, agriculture, a cosmetic or detergent composition, a textile process, an oil and gas exploitation process.

[0019] Finally, the present invention also relates to the use of said water-soluble polymer as a dispersant, coagulant, flocculant, thickener, grinding agent, friction reducer, super-absorbent, retention agent. DESCRIPTION OF THE INVENTION

[0020] As used herein, the term "polymer" refers to a homopolymer or copolymer comprising at least two different monomers.

[0021] As used herein, the expression "A and / or B" means "A or B, or A and B".

[0022] As used herein, the term "water-soluble polymer" refers to a polymer that gives an aqueous solution (concentration of 10 gL-1 at 25°C) without insoluble particles after being properly mixed with water.

[0023] The present invention relates to a water-soluble polymer obtained from a composition comprising at least one 2-dimethylaminoethyl acrylate monomer and / or its salts combined with at least one tocopherol and / or its derivatives, or one tocotrienol and / or its derivatives.

[0024] Tocopherol and its derivatives, and tocotrienol and its derivatives, exist in four different forms α (alpha), β (beta), γ (gamma), and δ (delta) depending on their substituents and positions.

[0025] Tocopherol derivatives

[0026] [Tables 1] Derived\ of tocopherols R' R- R3 Nam CH; CH; ! CH; i Tocopherol CH; H! CH; P-; Tocopherol H' CH; | CH; : V- Tocopherol HH! CH; i 3- Tocopherol

[0027] Tocotrienol derivatives

[0028] [Tables2] Tocotrienol derivatives i R5 R- R3 .Name i CH, CH; CHj î a- i î Tocotrienol § CH; HCH; p- § Tocotrienol i H CH; CH; ; -y-! Tocotrienol § HH CH3 S- J Tocotrienol §

[0029] In a preferred embodiment of the invention, the acrylate monomer of 2-dimethylaminoethyl and / or its salts is / are combined with a tocopherol and / or a tocotrienol.

[0030] In a preferred embodiment of the invention, the 2-dimethylaminoethyl acrylate monomer and / or its salts is / are combined with a tocopherol.

[0031] In this case, the 2-dimethylaminoethyl acrylate monomer and / or its salts is / are preferably combined with an α-tocopherol.

[0032] The amount of tocopherol(s) and / or its derivatives, and / or tocotrienol(s) and / or its / their derivatives is preferably between 1 ppm and 10,000 ppm, based on the amount of 2-dimethylaminoethyl acrylate monomer and / or its salts, preferably between 1 ppm and 1,000 ppm, more preferably between 5 ppm and 500 ppm, and even more preferably between 5 ppm and 50 ppm.

[0033] Tocopherol and / or its derivatives, or tocotrienol and / or its derivatives, may be combined with 2-dimethylaminoethyl acrylate monomer and / or its salts at any time.

[0034] More specifically, tocopherol and / or its derivatives or tocotrienol and / or its derivatives may be combined before, during, at the end of or after the synthesis of the 2-dimethylaminoethyl acrylate monomer and / or its salts. Preferably, they are added after the synthesis of the 2-dimethylaminoethyl acrylate monomer.

[0035] Tocopherol and / or its derivatives or tocotrienol and / or its derivatives may be combined before, during, at the end of or after a purification step of the 2-dimethylaminoethyl acrylate monomer and / or its salts. Preferably, they are added after the purification step.

[0036] The purification step(s) include, for example and without limitation, distillation, fractional distillation, crystallization. Preferably, the purification step is fractional distillation.

[0037] Tocopherol and / or its derivatives or tocotrienol and / or its derivatives may be combined before or during storage of the 2-dimethylaminoethyl acrylate monomers and / or their salts, or just before their polymerization or just before their quaternization or salification. Preferably, they are combined before storage of the 2-dimethylaminoethyl acrylate monomers and / or their salts.

[0038] In order to increase the effectiveness of inhibiting the formation of vinyl acrylate, tocopherol and / or its derivatives, or tocotrienol and / or its derivatives, and 2-dimethylaminoethyl acrylate monomer and / or its salts, are preferably mixed homogeneously.

[0039] The mixing may be carried out, for example and without limitation, by stirring, in a static mixer, in a recirculation loop, by gas bubbling. Preferably the mixing is carried out by stirring.

[0040] The duration of the mixing ensures the homogeneity of the composition. In general, the mixing lasts at least 1 min, preferably at least 10 min, more preferably at least at least 30 min, and even more preferably at least 60 min.

[0041] According to the prior art, 2-dimethylaminoethyl acrylate monomers and / or their salts are generally stored for less than 3 months in order to limit the amount of vinyl acrylate formed to about 20 ppm. According to the invention, said monomers can be stored for 6 months, and the amount of vinyl acrylate is less than 10 ppm based on the amount of 2-dimethylaminoethyl acrylate monomers, and after 12 months, the amount of vinyl acrylate formed is less than 20 ppm.

[0042] The concentration of vinyl acrylate in 2-dimethylaminoethyl acrylate monomers can be determined using gas chromatography (GC) analysis; Agilent 7820A instrument, with an MS detector equipped with a 30m DB-WAX column, helium for carrier gas at 1 mL / min. The temperature of the injectors and the transfer line are maintained at 250°C. The injection is made with 1 pL at a ratio of 1:100. The oven temperature is 80°C for 5 min, then increased by 5°C / min to 122°C for 2 min, then the temperature is increased to 240°C by 35°C / min for 11 min.

[0043] The 2-dimethylaminoethyl acrylate monomer may be in its neutral, quaternized, or salified form. The 2-dimethylaminoethyl acrylate may be partially or fully quaternized or salified. Preferably the 2-dimethylaminoethyl acrylate monomer, when quaternized, is quaternized with methyl chloride.

[0044] Preferably the water-soluble polymer of the invention comprises at least 1 mol% of the 2-dimethylaminoethyl acrylate monomer and / or its salts (from the composition), based on the total number of moles of monomers in the polymer, preferably at least 2 mol%, more preferably at least 5 mol%, more preferably at least 10 mol%, more preferably at least 15 mol%, more preferably at least 20 mol%, more preferably at least 25 mol%, even more preferably at least 30 mol%.

[0045] Another subject of the invention is a composition comprising: - from 1 to 99.9999% of at least one 2-dimethylaminoethyl acrylate monomer and / or its salts; - from 1 to 10,000 ppm of at least one tocopherol and / or its derivatives, or one tocotrienol and / or its derivatives, based on the amount of 2-dimethylaminoethyl acrylate and / or its salts; - optionally at least one additive chosen from biocides, polymerization inhibitors, moisture absorbers, color stabilizers.

[0046] In a preferred embodiment of the invention, the composition comprises between 5 and 95% of 2-dimethylaminoethyl acrylate monomer and / or its salts.

[0047] In a preferred embodiment of the invention, the composition comprises between 2 and 10,000 ppm of at least one tocopherol and / or its derivatives, or one tocotrienol and / or its derivatives based on the amount of 2-dimethylaminoethyl acrylate and / or its salts, more preferably between 5 and 1,000 ppm.

[0048] Above 10,000 ppm of tocopherol and / or its derivatives, or tocotrienol and / or its derivatives, based on the amount of 2-dimethylaminoethyl acrylate and / or its salts, the economic interest of the composition drops dramatically. Below 1 ppm of tocopherol and / or its derivatives, or tocotrienol and / or its derivatives, the effect of preventing the formation of vinyl acrylate is much lower and is therefore not significant.

[0049] The composition of the invention may comprise other additives, for example and without limitation biocides, polymerization inhibitors, moisture absorbers, color stabilizers, and the like.

[0050] In a preferred embodiment of the invention, the composition comprises at least one color stabilizer chosen from: niacinamide, retinol, 3-tert-butyl-4-hydroxyanisole (3-BHA), 2-tert-butyl-4-hydroxyanisole and 2,6,-di-tert-butyl-4-methylphenol. More preferably, the color stabilizer is 2,6-di-tert-butyl-4-methylphenol.

[0051] When using a color stabilizer, the weight ratio between tocopherol or its derivatives, or tocotrienol or its derivatives, and the color stabilizer is between 1 and 100, preferably between 2 and 10. The water-soluble polymer

[0052] The water-soluble polymer of the invention can be obtained by polymerization of the composition described above and / or non-ionic monomers, and / or anionic monomers, and / or cationic monomers, and / or zwitterionic monomers. Since the 2-dimethylaminoethyl acrylate monomer is cationic, the water-soluble polymer of the invention is cationic or amphoteric.

[0053] The additional cationic monomer(s) that may be used in the invention are preferably chosen from water-soluble vinyl monomers, more particularly of the acrylamide, acrylic, allyl or maleic type having a quaternary ammonium group. In particular and without limitation, quaternized or salified 2-dimethylaminoethyl acrylate (DMAEA), quaternized or salified 2-dimethylaminoethyl methacrylate (DMAEMA), quaternized or salified allylamine, quaternized or salified allydimethylamine, quaternized or salified diallylmethylamine, dimethyldiallylammonium chloride (DADMAC), quaternized or salified di-methylaminopropyl acrylamide, acrylamidopropyltrimethylammonium chloride (APTAC), dimethylami- quaternized or salified monopropyl and methacrylamidopropyltrimethylammonium chloride (MAPTAC). Preferably, the additional cationic monomer is dimethyldiallylammonium chloride (DADMAC).

[0054] The water-soluble polymer preferably comprises between 0 and 99 mol% of additional cationic monomers based on the total number of moles of monomers of said polymer, preferably 99 mol% or less, more preferably 98 mol% or less, more preferably 95 mol% or less, more preferably 90 mol% or less, more preferably 85 mol% or less, more preferably 80 mol% or less, more preferably 75 mol% or less, more preferably 70 mol% or less, even more preferably 50 mol% or less,

[0055] The non-ionic monomer(s) that can be used in the invention are preferably chosen from water-soluble vinyl monomers. Preferred monomers belonging to this family are, for example, acrylamide, methacrylamide, N-isopropylacrylamide, N-tert-butylacrylamide, N,N-dimethylacrylamide, N-methylolacrylamide, N-vinylformamide, N-vinylimidazole, N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone, acryloylmorpholine (ACMO), diacetone acrylamide, and mixtures thereof. Preferably, the non-ionic monomer is acrylamide.

[0056] The water-soluble polymer preferably comprises between 0 and 99 mol% of non-ionic monomers based on the total number of moles of monomers of said polymer, preferably 95 mol% or less, preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less.

[0057] The anionic monomer(s) that can be used in the invention are preferably selected from monomers having a carboxylic function and the salts thereof; monomers having a sulfonic acid function and the salts thereof; monomers having a phosphoric acid function and the salts thereof. The anionic monomers include, for example, acrylic acid, acrylamido-tert-butylsulfonic acid, methacrylic acid, maleic acid, itaconic acid; and hemiesters thereof. The most preferred monomers are acrylic acid, acrylamido-tert-butylsulfonic acid (ATBS), 3-Allyloxy-2-hydroxy-1-propanesulfonic acid, and the salts thereof. Preferably, the anionic monomer is acrylic acid.

[0058] The anionic monomers may be non-salified, or partially or completely salified.

[0059] The salified form preferably corresponds to an alkali metal (Li, Na, K...), an alkali-earth metal (Ca, Mg...) or ammonium salts, in particular qua-ammonium ternary. The preferred salts are sodium salts.

[0060] The non-salified form corresponds to the acid form of the anionic monomer, for example CH2=CH-C(=O)OH in the case of acrylic acid. Salification can be carried out before and / or during and / or after polymerization. Salification can be partial or total.

[0061] The anionic part of the water-soluble polymer can be obtained by post-hydrolysis.

[0062] A post-hydrolysis reaction is a chemical reaction on a polymer after its formation by polymerization of monomers. This step consists of reacting hydrolyzable functional groups of monomers, preferably non-ionic monomers, more preferably monomers containing a hydrolyzable function (preferably an amide or an ester), with a hydrolysis agent. This hydrolysis agent may be an enzyme, an ion exchange resin, or an alkali metal. Preferably, the hydrolysis agent is a Brönsted base, for example, NaOH or KOH. During this post-hydrolysis step of the polymer, the number of carboxylic acid functions (COOH) and / or carboxylate functions (COO-) increases. Indeed, the reaction between the hydrolysis agent (for example a Brônsted base) and the hydrolyzable function (for example an amide or an ester function) present in the polymer produces carboxylate groups.Hydrolysis can be carried out before and / or during and / or after polymerization. Hydrolysis can be partial or total.

[0063] The water-soluble polymer preferably comprises between 0 and 100 mol% of salified form of anionic monomers based on the total number of moles of anionic monomers in the polymer.

[0064] The water-soluble polymer preferably comprises between 0 and 99 mol% of anionic monomer based on the total number of moles of monomers of said polymer, preferably 40 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 10 mol% or less.

[0065] In a particular embodiment of the invention, the anionic monomer is 2-acrylamido-2-methylpropane sulfonic acid in its hydrated form. The hydrated form of 2-acrylamido-2-methylpropane sulfonic acid is a particular form of 2-acrylamido-2-methylpropane sulfonic acid obtainable by controlled crystallization of 2-acrylamido-2-methylpropane sulfonic acid monomer. U.S. Patent No. 10,759,746 describes how to obtain the hydrated form of 2-acrylamido-2-methylpropane sulfonic acid.

[0066] One or more zwitterionic monomers and one or more hydrophobic monomers may be used as additional monomers in the polymer of the invention.

[0067] Those skilled in the art know that a polymer composition cannot exceed 100 mol% of monomers when the water-soluble polymer according to the invention is prepared. He will thus adjust the quantities of monomer(s) described previously so as not to exceed 100% in moles.

[0068] According to the invention, the water-soluble polymer may have a linear structure, a branched, star, comb, block, micro-block structure or a polydispersity controlled in molecular weight. These properties may be obtained by selecting one or more of the following elements: the initiator, the transfer agent, the polymerization technique.

[0069] The general knowledge of a person skilled in the art allows him to prepare a water-soluble polymer having one of these types of structure. The water-soluble polymer of the invention, having a specific morphology as described above, remains water-soluble.

[0070] The water-soluble polymer may be crosslinked. When a crosslinking agent is used, the amount used is such that the water-soluble polymer remains water-soluble. Those skilled in the art know how to adjust the amount of crosslinking agent and, where applicable, the amount of the transfer agent, so that the water-soluble polymer remains water-soluble.

[0071] In a preferred embodiment of the invention, the water-soluble polymer of the invention is not crosslinked.

[0072] The water-soluble polymer according to the invention preferably has a weight-average molecular weight of between 50,000 g / mol and 30,000,000 g / mol, preferably between 100,000 g / mol and 20,000,000 g / mol, more preferably between 500,000 g / mol and 15,000,000 g / mol. The weight-average molecular weight is preferably greater than or equal to 1 million g / mol, more preferably greater than or equal to 2 million g / mol, even more preferably greater than or equal to 10 million g / mol.

[0073] According to the present invention, the weight average molecular weight is determined by the intrinsic viscosity. The intrinsic viscosity can be measured by methods known to those skilled in the art. The intrinsic viscosity can be calculated from the reduced viscosity values ​​for different concentrations by a graphical method consisting of plotting the reduced viscosity values ​​(on the y-axis) as a function of the concentrations (on the x-axis) and extrapolating the curve to a concentration of zero. The intrinsic viscosity value is plotted on the y-axis or by using the least squares method. Then, the weight average molecular weight can be determined by the Mark-Houwink equation: [î]] = K Ma

[0074] in which:

[0075] [q] is the intrinsic viscosity of the polymer determined by a measurement method of solution viscosity,

[0076] K is an empirical constant,

[0077] M is the molecular weight of the polymer,

[0078] a is the Mark-Houwink coefficient.

[0079] a and K depend on the particular polymer-solvent system. There are tables that give the values ​​of a and K as a function of the polymer-solvent system.

[0080] The formation of the water-soluble polymer does not require a specific polymerization process.The water-soluble polymer can be obtained by any polymerization techniques known to those skilled in the art resulting in a polymer which is preferably in powder form, such as the following techniques: gel polymerization followed by drying and grinding steps; precipitation polymerization; solution polymerization, followed by a spray drying step; inverse emulsion polymerization, followed by a spray drying step; inverse suspension polymerization, advantageously to obtain microbeads; micellar polymerization followed or not by a precipitation step; post-hydrolysis or co-hydrolysis polymerization; what is called a “matrix”, radical, or controlled radical polymerization, and more particularly of the RAFT (Reversible Addition-Fragmentation Chain Transfer) type.

[0081] The polymerization of water-soluble monomers is a radical polymerization. A radical polymerization means, within the meaning of the invention, a radical polymerization using at least one UV, azo, redox or thermal initiator or a controlled radical polymerization (CRP) technique or a matrix polymerization technique. The water-soluble polymer can be used in any form known to those skilled in the art such as an aqueous solution, a powder, a water-in-oil emulsion, or a polymer dispersion in a brine. Preferably, as mentioned above, the water-soluble polymer is in a powder form.

[0082] When polymerizing 2-dimethylaminoethyl acrylate monomers and / or their salts combined with at least one tocopherol or its derivatives, or tocotrienol or its derivatives, the vinyl acrylate content is generally less than 20 ppm based on the total amount of 2-dimethylaminoethyl acrylate monomers and / or their salts used during the polymerization, preferably less than 10 ppm, more preferably less than 5 ppm.

[0083] The non-ionic monomer used in the polymer of the invention is preferably an acrylamide. The acrylamide is preferably produced from acrylonitrile by a biological process comprising the use of nitrile hydratase. Improved nitrile hydratases have been developed to increase the productivity of the biological process. Generally, the improvement involves modifying the protein sequence of a wild-type nitrile hydratase. For example, some improvements are made by modifying the alpha and / or beta subunit of the wild-type nitrile hydratase protein sequence. The following paragraphs describe an improved nitrile hydratase.

[0084] The following paragraphs describe an improved nitrile hydratase.

[0085] An improved nitrile hydratase is derived from a wild-type nitrile hydratase but is not limited to any specific wild type. Here, a "wild-type nitrile hydratase" indicates: a nitrile hydratase isolated from living organisms found in nature (microorganisms such as soil bacteria, for example); the amino acid sequence forming the enzyme and the base sequence of the gene encoding the enzyme are not artificially deleted, inserted, or substituted with other amino acids or bases; and the nitrile hydratase retains the original properties that occur naturally.

[0086] A "wild-type nitrile hydratase" has a top structure formed with α and β subunit domains, and contains a non-heme iron atom, or a non-corrin cobalt atom as a prosthetic molecule. Such a nitrile hydratase is identified and referred to as an iron-containing nitrile hydratase or a cobalt-containing nitrile hydratase.

[0087] For a cobalt-containing nitrile hydratase, examples are those derived from a strain Rhodococcus rhodochrous J1 (may be referred to hereinafter as "strain J1") or derived from Pseudonocardia thermophila JCM3095. A cobalt-containing nitrile hydratase derived from strain J1 is linked to a cobalt atom through a site identified as a cysteine ​​cluster that forms the active site of the α-subunit.

[0088] A preferred wild-type nitrile hydratase is Rhodococcus rhodochrous Jl-H, Rhodococcus rhodochrous M8, Rhodococcus ruber TH, Rhodococcus pyridinovorans MW3, and P.thermophila JCM3095.

[0089] An improved (mutant) nitrile hydratase is generally formed by substituting amino acids of a wild-type nitrile hydratase into the alpha and / or beta subunit. Amino acid sequences of wild-type nitrile hydratases to be substituted are made public in NCBI databases such as GenBank (http: / / www.ncbi.nlm.nih.gov / ) and the like.

[0090] The improved nitrile hydratase is characterized by modifying the amino acid sequence of a wild-type nitrile hydratase, said modification comprising at least one amino acid modification, preferably at least two amino acid modifications, more preferably at least three amino acid modifications on the beta subunit selected from the following list: 14S, 14Q, 14D, 17G, 17E, 17A, 17V, 17W, 43H, 43Q, 43N, 46H, 46T, 48D, 48W, 48D, 57V, 57M, 57G, 69F, 69T, 77P, 77E, 95Y, 95M, 95V, 97A, 97W, 107M, 107K, 107H, 114Y, 114F, 114W, 114M, 133R, 133G, 1331, 167S, 167T, 167Y, 179C, 179M, 179T, 202P, 202W, 218T, 218H, 218V, 219A, 219N, 219R; and at least one amino acid modification on the alpha subunit selected from the following list: 49H, 49W, 68G, 68T, 112V, 112P, 174K, 174L, 174C, 187A, 187G, 187V.

[0091] The numbers correspond to an amino acid residue at position "XXX" (a number comprising 1, 2 or 3 digits) counted downward from the N-terminal amino acid residue in the amino acid sequence of a [3] subunit or the alpha subunit.

[0092] Possible combinations are listed below. AA means amino acid, and commonly used abbreviations for amino acids are used, such as A for Alanine. If a position is not mentioned, the amino acid is the amino acid of the wild-type nitrile hydratase. For example, position [315 is not mentioned in the following combinations, and this means that the amino acid at position [315 is the amino acid of the wild-type amino acid at position [315. The following combinations include the al74L modification, but the description also includes the same combinations in which the al74L modification is replaced by the al74K or al74C modifications.

[0093] List of combinations

[0094] al74L, [317G, [346T, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0095] al74L, [317G, [348W, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0096] al74L, [317G, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0097] al74L, [317G, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0098] al74L, [317G, [348N, [357M, [395V, [3114Y, [3167T, [3218H, [3219A

[0099] al74L, [317G, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0100] al74L, [317G, [348N, [357M, [395V, [3114Y, [3167T, [3218H, [3219A

[0101] al74L, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0102] al74L, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0103] al74L, [346T, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0104] al74L, [346T, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0105] al74L, [346T, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219R

[0106] al74L, [346T, [348N, [357M, [395V, [3114W, [3167S, [3218H, [3219R

[0107] al74L, [346T, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0108] al74L, [317G, [346T, [348N, [357K, [395V, [3114Y, [3167S, [3218H, [3219A

[0109] al74L, [317G, [346T, [348N, [357K, [395V, [3114Y, [3167S, [3218H, [3219A

[0110] al74L, [317G, [346T, [348N, [357K, [395V, [3114Y, [3167S, [3218H, [3219R

[0111] al74L, [317G, [346T, [348N, [357K, [395V, [3114Y, [3167S, [3218H, [3219R

[0112] al74L, [317X, [348N, [357M, [395V], [3114F, [3167S, [3218H], [3219A

[0113] in the description,

[0114] al74L, [317X, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0115] al74L, [317X, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219R

[0116] al74L, [317X, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219R

[0117] al74L, [317X, [346T, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219R

[0118] al74L, [317X, [346T, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0119] al74L, [317X, [346T, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0120] al74L, [317X, [346T, [348N, [357K, [395V, [3114W, [3167S, [3218H, [3219A

[0121] al74L, [317X, [346T, [348N, [357K, [395V, [3114F, [3167S, [3218A, [3219A

[0122] al74L, [317X, [346T, [348N, [357K, [395V, [3114F, [3167S, [3218Q, [3219A

[0123] al74L, [317X, [346T, [348N, [357K, [395V, [3114F, [3167S, [3218H, [3219R

[0124] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0125] al74L, [317X, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0126] al74L, [317X, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0127] al74L, [317X, [346T, [348N, [357M, [395V, [3114W, [3167S, [3218H, [3219A

[0128] al74L, [317X, [346T, [348N, [357K, [395V, [3114W, [3167S, [3218H, [3219A

[0129] al74L, [317X, [346T, [348N, [357M, [395V, [3114W, [3167S, [3218H, [3219R

[0130] al74L, [317X, [346T, [348N, [357K, [395V, [3114W, [3167R, [3218H, [3219R

[0131] al74L, [317X, [348N, [357K, [395V, [3114W, [3167S, [3218H, [3219R

[0132] al74L, [317G, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0133] al74L, [317G, [357M, [395V, [3107L, [3114Y, [3167S, [3218H, [3219A

[0134] al74L, [317G, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0135] al74L, [317G, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0136] al74L, [317G, [348N, [357M, [395V, [31O7K, [3114Y, [3167T, [3218H, [3219A

[0137] al74L, [317G, [348N, [357M, [395V, [31O7L, [3114Y, [3167S, [3218H, [3219A

[0138] al74L, [317G, [348N, [357M, [395V, [31O7L, [3114Y, [3167T, [3218H, [3219A

[0139] al74L, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0140] al74L, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0141] al74L, [346T, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0142] al74L, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0143] al74L, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0144] al74L, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R

[0145] al74L, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0146] al74L, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0147] al74L, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0148] al74L, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0149] al74L, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0150] al74L, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0151] al74L, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0152] al74L, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0153] al74L, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0154] al74L, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0155] al74L, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0156] al74L, [317X, [346T, [348N, [357M, [395V, |3107H, [3114F, [3167S, [3218H, [3219A

[0157] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0158] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218A, [3219A

[0159] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218Q, [3219A

[0160] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0161] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0162] al74L, [317X, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0163] al74L, [317X, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0164] al74L, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0165] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0166] al74L, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R

[0167] al74L, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167R, [3218H, [3219R

[0168] al74L, [317X, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R]

[0169] al74L, [314S, [317G, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0170] al74L, [314S, [317G, [357M, [395V, [3107L, [3114Y, [3167S, [3218H, [3219A

[0171] al74L, [314S, [317G, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0172] al74L, [314S, [317G, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0173] al74L, [314S, [317G, [348N, [357M, [395V, [31O7K, [3114Y, [3167T, [3218H, [3219A

[0174] al74L, [314S, [317G, [348N, [357M, [395V, [3107L, [3114Y, [3167S, [3218H, [3219A

[0175] al74L, [314S, [317G, [348N, [357M, [395V, [3107L, [3114Y, [3167T, [3218H, [3219A

[0176] al74L, [314S, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0177] al74L, [314S, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0178] al74L, [314S, [346T, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0179] al74L, [314S, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0180] al74L, [314S, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0181] al74L, [314S, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R

[0182] al74L, [314S, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0183] al74L, [314S, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0184] al74L, [314S, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0185] al74L, [314S, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0186] al74L, [314S, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0187] al74L, [314S, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0188] al74L, [314S, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0189] al74L, [314S, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0190] al74L, [314S, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0191] al74L, [314S, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0192] al74L, [314S, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0193] al74L, [314S, [317X, [346T, [348N, [357M, [395V, |3107H, [3114F, [3167S, [3218H, [3219A

[0194] al74L, [314S, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0195] al74L, [314S, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218A, [3219A

[0196] al74L, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218Q, [3219A

[0197] al74L, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0198] al74L, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0199] al74L, [317X, [343Q, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0200] al74L, [317X, [343Q, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0201] al74L, [317X, [343Q, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0202] al74L, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0203] al74L, [317X, [343Q, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R

[0204] al74L, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167R, [3218H, [3219R

[0205] al74L, [317X, [343Q, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R]

[0206] al74L, [314S, [317X, [346T, [348N, [357M, [395V, |3107H, [3114F, [3167S, [3218H, [3219A

[0207] al74L, [314S, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0208] al74L, [314S, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218A, [3219A

[0209] al74L, [317X, [343Q, [346T, [348N, [357K, [377P, [395V, [31O7K, [3114F, [3167S, [3218Q, [3219A

[0210] al74L, [317X, [343Q, [346T, [348N, [357K, [377P, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0211] al74L, [317X, [343Q, [346T, [348N, [357K, [377P, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0212] al74L, [317X, [343Q, [348N, [357K, [377P, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0213] al74L, [317X, [343Q, [348N, [357M, [377P, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0214] al74L, [317X, [343Q, [346T, [348N, [357M, [377P, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0215] al74L, [314S, [346T, [348N, [357M, [397A, [31O7K, [3114W, [3167S, [3218H, [3219R

[0216] al74L, [314S, [346T, [348N, [357M, [397A, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0217] al74L, [314S, [317G, [346T, [348N, [357K, [397A, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0218] al74L, [314S, [346T, [348N, [357K, [397A, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0219] al74L, [314S, [317G, [346T, [348N, [357K, [397A, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0220] al74L, [314S, [317G, [346T, [348N, [357K, [397A, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0221] al74L, [314S, [317X, [348N, [357M, [397A, [31O7K, [3114F, [3167S, [3218H, [3219A

[0222] al74L, [314S, [317X, [348N, [357M, [397A, [31O7K, [3114F, [3167S, [3218H, [3219A

[0223] al74L, [314S, [317X, [348N, [357M, [397A, [31O7K, [3114F, [3167S, [3218H, [3219R

[0224] a49H, [317G, [348N, [357M, [395V, [3114Y, [3167T, [3218H, [3219A

[0225] a49H, [317G, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0226] a49H, [317G, [348N, [357M, [395V, [3114Y, [3167T, [3218H, [3219A

[0227] a49H, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0228] a49H, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0229] a49H, [346T, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0230] a49H, [346T, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219A

[0231] a49H, [346T, [348N, [357M, [395V, [3114Y, [3167S, [3218H, [3219R

[0232] a49H, [346T, [348N, [357M, [395V, [3114W, [3167S, [3218H, [3219R

[0233] a49H, [317X, [346T, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219R

[0234] a49H, [317X, [346T, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0235] a68T, [317X, [346T, [348N, [357M, [395V, [3114F, [3167S, [3218H, [3219A

[0236] a68T, [317X, [346T, [348N, [357K, [395V, [3114W, [3167S, [3218H, [3219A

[0237] a68T, [317X, [346T, [348N, [357K, [395V, [3114F, [3167S, [3218A, [3219A

[0238] a68T, [317X, [346T, [348N, [357K, [395V, [3114F, [3167S, [3218Q, [3219A

[0239] a68T, [317X, [346T, [348N, [357K, [395V, [3114F, [3167S, [3218H, [3219R

[0240] a68T, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0241] a68T, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R

[0242] a68T, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0243] a68G, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0244] a68G, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0245] a68G, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0246] a68G, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219R

[0247] a68G, [317X, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0248] a68G, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0249] al 12V, [317X, [346T, [348N, [357M, [395V, [31O7K, [3114F, [3167S, [3218H, [3219A

[0250] al 12V, [317X, [346T, [348N, [357M, [395V, |3107H, [3114F, [3167S, [3218H, [3219A

[0251] al 12V, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0252] al 12V, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218A, [3219A

[0253] al 12V, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218Q, [3219A

[0254] al 12V, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0255] al87G, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0256] al87G, [317X, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0257] al87G, [317X, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0258] al87G, [314S, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219R

[0259] al87G, [314S, [346T, [348N, [357M, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0260] al87V, [314S, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0261] al87V, [314S, [317G, [346T, [348N, [357K, [395V, [31O7K, [3114Y, [3167S, [3218H, [3219A

[0262] al87V, [314S, [317X, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218A, [3219A

[0263] al87V, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218Q, [3219A

[0264] al87V, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0265] al87V, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114F, [3167S, [3218H, [3219R

[0266] al87V, [317X, [343Q, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0267] al87V, [317X, [343Q, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0268] al87V, [317X, [343Q, [346T, [348N, [357M, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0269] al87V, [317X, [343Q, [346T, [348N, [357K, [395V, [31O7K, [3114W, [3167S, [3218H, [3219A

[0270] Nitrile hydratases are sensitive to impurities contained in the acrylonitrile solution, more specifically, hydrocyanic acid, and or its salts, decreases their effectiveness.

[0271] The content of hydrocyanic acid, and / or its salts, in the acrylonitrile solution depends on each producer and varies over time. This is a disadvantage as the amount of nitrile hydratase must be continuously adjusted during the acrylonitrile conversion, because otherwise the final acrylamide may have a high content of residual acrylonitrile which can lead to safety problems.

[0272] To maintain the conversion rate of acrylonitrile to acrylamide and lower the amount of residual acrylonitrile in the acrylamide solution, it is necessary to overdose the nitrile hydratase. However, overdosing can lead to several problems in the downstream process such as filtration problems that can lead to high coloration and turbidity of the final acrylamide product.

[0273] To moderate the effect of the hydrocyanic acid contained in the acrylonitrile solution, the latter can be purified by bringing the acrylonitrile solution into contact with an aldehyde compound.

[0274] The simplest aldehyde is acetaldehyde, but this molecule is known to be carcinogenic, to have a low flash point and a boiling point at 20°C, which makes its use complicated.

[0275] The aldehyde compound may be aliphatic or aromatic.

[0276] The aldehyde compound may be a compound obtained by reacting a polyacrylamide with a difunctional aldehyde, for example by reacting a polyacrylamide with a glyoxal, a propanediol, a butanediol, a pentanediol, or it may be a propionaldehyde, a butyraldehyde or a mixture of propionaldehyde and butyraldehyde. Preferably, the aldehyde compound is a butyraldehyde.

[0277] The reacting polyacrylamide may be obtained by polymerization of non-ionic monomers and / or anionic monomers, and / or cationic monomers, and / or amphoteric monomers.

[0278] The reacting polyacrylamide preferably has a weight-average molecular weight of between 1,000 g / mol and 10,000,000 g / mol.

[0279] The reacting polyacrylamide may be linear, structured or crosslinked. Preferably, the reacting polyacrylamide is linear.

[0280] The acrylonitrile solution comprises at least 99% by weight of acrylonitrile, preferably at least 99.5% by weight.

[0281] The amount of aldehyde compound brought into contact with the acrylonitrile solution is between 1 ppm and 500 ppm relative to the amount of acrylonitrile solution, preferably between 5 ppm and 200 ppm, more preferably between 10 ppm and 100 ppm, and even more preferably between 20 ppm and 50 ppm.

[0282] The contact time between the acrylonitrile solution and the aldehyde compound is between 5 minutes and 48 hours, preferably between 30 minutes and 24 hours, more preferably between 1 hour and 12 hours.

[0283] Mixing of the acrylonitrile solution and the aldehyde compound may be done in the storage tank, in an acrylamide reactor, or on the feed line to the acrylamide reactor.

[0284] Contact between the acrylonitrile solution and the aldehyde compound can be carried out with a static mixer, with a recirculation line, by stirring, or by natural diffusion.

[0285] The purified acrylonitrile solution generally contains less than 20 ppm of hydrocyanic acid, preferably less than 10 ppm, more preferably less than 5 ppm.

[0286] Acrylamide can be obtained by enzymatic bioconversion of a purified acrylonitrile solution obtained by contacting the acrylonitrile solution with an aldehyde compound.

[0287] The polyacrylamide polymer can be obtained by polymerization of acrylamide obtained by enzymatic bioconversion of a purified acrylonitrile solution.

[0288] The polymer obtained from acrylamide obtained from purified acrylonitrile can be used in hydrocarbon (oil and / or gas) recovery; in well drilling and cementing; in hydrocarbon (oil and / or gas) well stimulation, e.g., hydraulic fracturing, conforming, diversion; in open, closed or semi-closed water treatment; in fermentation paste processing; in papermaking; in construction; in wood processing; in hydraulic composition processing (concrete, cement, mortar and aggregates); in mining industry; in cosmetic formulation; in detergent formulation; in textile manufacturing; in battery component manufacturing; in geothermal energy; in sanitary napkin manufacturing; or in agriculture.

[0289] Uses of 2-dimethylaminoethyl acrylate polymers

[0290] The present invention also relates to the use of the water-soluble polymer of the invention in water treatment, pulp dehydration, a papermaking process, agriculture, a cosmetic composition, a detergent composition, a textile process, an oil and gas exploitation process, such as enhanced oil recovery, fracturing, mining such as tailings treatment.

[0291] The present invention also relates to the use of the water-soluble polymer of the invention as a dispersant, coagulant, flocculant, thickener, grinding agent, friction reducer, superabsorbent, retention agent.

[0292] The present invention will be further described with the aid of the following examples, which are merely illustrative of the invention and are not intended to limit it. Unless otherwise indicated, all percentages are by weight (wt%). Description of figures

[0293] [Fig.l] illustrates the evaluation of the friction reducing effect of polymers 1 to 5 by FlowLoop tests. EXAMPLES Example 1 - Storage & Insolubility Rate Preparation of the composition

[0294] At the end of the synthesis of 2-dimethylaminoethyl acrylate (DMAEA) monomers, the monomers are purified via distillation. The distillate fraction, at least 98%, of 2-dimethylaminoethyl acrylate monomers is collected. A polymerization inhibitor, monomethyl ether hydroquinone, is added (1000 ppm) and mixed homogeneously. Tocopherol and / or its derivatives, or a tocotrienol and / or its derivatives is then added and mixed homogeneously for 30 minutes at 20°C in air. The prepared composition is then transferred for storage and stored in air for 1 to 12 months. The 2-dimethylaminoethyl acrylate monomers are conventionally quaternized with methyl chloride, the quaternization being known per se to those skilled in the art, before being polymerized.

[0295] The different compositions prepared are summarized in Table 3.

[0296] [Tables3] Composition Tocopherols or tocotrienols Concentration of Tocopherols or Tocotrienols Composition 1 reference - - Composition 2 invention a-tocopherol 20 ppm Composition 3 invention 200 ppm Composition 4 invention y-tocopherol 25 ppm Composition 5 invention 250 ppm Composition 6 invention a-tocotrienol 20 ppm Composition 7 invention 300 ppm Composition 8 mvennon a-tocopherol + 30 ppm of 2,6,-di-tert-butyl-4-niethylphenol 20 ppm Composition 9 invention 200 ppm

[0297] The concentration of vinyl acrylate in 2-dimethylaminoethyl acrylate monomers is determined by gas chromatography (GC); Agilent 7820A instrument with an MS detector equipped with a DB-WAX column, 30m, helium for carrier gas at 1 mL / min. The temperature of the injectors and the transfer line is maintained at 250°C. The injection is made with 1 pL at a ratio of 1:100. The oven temperature is at 80°C for 5 min, then increased by 5°C / min to 122°C for 2 min, then the temperature is increased to 240°C, at 35°C / min for 11 min.

[0298] Storage & insolubility rate in polymer preparation

[0299] The UL viscosity (Brookfield viscosity), the insoluble content and the insoluble points are measured on a polymer composed of 70 mol% acrylamide and 30 mol% quaternized DMAEA prepared by conventional bulk polymerization.

[0300] UL viscosity measurement: UL viscosity is measured using a Brookfield viscometer equipped with a UL adapter, the unit of which rotates at 60 rpm (0.1 percent by weight of polymer in 1M sodium chloride saline solution) between 23 and 25°C.

[0301] The insoluble content is measured by transferring 1 g of the polymer solution into 200 ml of water at 20°C, and stirring for 2 h, then the dissolved solution is filtered with a 4 cm diameter filter having a porosity of 200 μm. After the filtered solution is completely drained, the filter paper is weighed. In the case of a non-filterable solution, the sieve filter is placed at 105°C for 4 h. The residual mass is used to determine the insoluble amount, and the insoluble content is related to the initial polymer mass. As mentioned above, the vinyl acrylate impurity creates covalent bonds between 2-dimethylaminoethyl acrylate monomers resulting in aggregates that do not pass through the filter.

[0302] The insoluble rate corresponds to the number and size of aggregates on the filter, after all the solution has passed through the filter, counted visually. The following scale is used: point (pt) between 1 and 3 mm; large point (bp) for more than 3 mm.

[0303] [Tables4] Composition Duration Concentration of vinyl acrylate in 2-dimethylaminoethyl acrylate monomers UL Viscosity (cps) Insoluble points Insoluble rate Composition 1 1 month 10 ppm 5.3 10 pts 1% 3 months 15 ppm. 53 20 bps $ % 6 months 40 ppm Not measurable Not filterable 10033 12 months 60 ppm Not measurable Not filterable 100% Composition 2 imWïOfs 1 month 2 ppm 5.3 5 pis i:% 3 months 5ppm 5.3 10 pts 1% 6 months 10 ppm 53 30 pis 2% 12 months 15 ppm 5.0 10 bps 1% Composition 3 Tî-JV&rçfîWÏ 1 month 1 PW 5.2 5 pis 1 % 3 months 5 ppm 54 10 pts 1% 6 months 8 ppm 5.1 30 pis 7 % ■ 12 months 18 ppm 54 10 bps 2¾ Composition 4 m'enlion 1 month 3 ppm 53 6 pis 1% 3 months 7 ppm 5.3 10 pts 1 % 6 months 10 ppm 5.0 30 pts 2% 12 months 20 ppm 5.2 20 bps 2% Composition 5 1 month 2 ppm 5.3 10 pts 1% 3 months 4 ppm 5.3 10 pts 1 % 6 months 12 ppm '5.3 30 pts 233 12 months 19ppm 5.0 10 bps 2 % Composition 6 tnvwtfios 1 month 3 ppm 5.2 10 pts 1 % 3 months 5 ppm 5.3 10 pts 1% 6 months 10 ppm 5.1 30 pts ?% 12 months 49 ppm 5.3 10 bps 7 Composition 7 WWW 1 month 1 ppm 5.3 10 pts r% 3 months 4 ppm 5.3 10 pts i% 6 months 7 ppm 5.0 30 pts 2% 12 months 18 ppm 5.2 15 bps 7 % Composition ë 1 month i ppm 54 10 pts 134 3 months 3 ppm 5.1 10 pts 1 34 6 months S ppm 5.0 30 pts 2 34 12 months 15 ppm 5.2 8 bps 2 34 Composition 9 lisVesfw 1 month <1 ppm 5.1 2 pts <1% 3 months 2ppm 5.2 5 pts 134 6 months 5 ppm 5.3 20 pts 134 12 months 12 ppm 5.3 5 bps 234 .

[0304] As can be seen from Table 4, the combination of 2-dimethylaminoethyl acrylate monomers and a tocopherol and / or its derivatives, or a tocotrienol and / or its derivatives, reduces the formation of vinyl acrylate during storage.

[0305] Even after only 1 month, the monomers of the invention have a reduced amount of vinyl acrylate. Thanks to the invention, the monomers can be stored for up to 12 months and still have an amount of vinyl acrylate equivalent to approximately 3 months of storage of conventional monomers.

[0306] Concerning the insoluble points, without the combination of the invention, the number of points corresponding to polymer aggregates is greater for monomers stored without tocopherol and / or its derivatives, or without a tocotrienol and / or its derivatives, even after one month. Example 2: Friction Reduction Test

[0307] Preparation of 2-dimethylaminoethyl acrylate polymers.

[0308] Different quaternized 2-dimethylaminoethyl acrylate / acrylamide (30% / 70%) copolymers were synthesized with different weight % of 2-dimethylaminoethyl acrylate monomers from composition 3, prepared in Example 1, after 6 months of storage. The polymers are obtained by conventional bulk polymerization.

[0309] The compositions of the polymers are summarized in Table 5.

[0310] [Tables5] Polymer % by weight of DMAEA combined with α-tocopherol in the quaternized DMAEA / acylamide copolymer Polymer 1 counterexample 0% by weight of 2-dimethylammoethyl acrylate Polymer 2 invention 5% by weight of 2-dimethylammoethyl acrylate Polymer 3 invention 30% by weight of 2-dimethylammoethyl acrylate Polymer 4 invention 50% by weight of 2-dimethylammoethyl acrylate Polymer 5 invention 80% by weight of 2-dimethylammoethyl acrylate

[0311] Preparation of a hydraulic fracturing fluid

[0312] Polymers 1 to 5 are added with stirring, at a concentration of 10,000 ppm, into a brine consisting of water, 85 g of sodium chloride (NaCl) and 33.1 g of calcium chloride (CaCl2, 2H2O) per liter of brine.

[0313] The resulting saline polymer solutions are then injected at a concentration of 0.05 pptg (pounds per thousand gallons) (which gives 0.006 g / L = 6 g / m3, since 1 pptg = 0.1198 g / L) into the recirculating brine for the flow loop tests that follow.

[0314] Flow Loop Friction Reduction Tests

[0315] A friction flow loop was constructed from 1 / 4 inch outside diameter stainless steel tubing (which gives 0.635 cm, since 1 inch = 2.54 cm), with a total length of 20 feet (which gives 6.096 m, since 1 foot = 0.3048 m). The test solutions are pumped from the bottom of a conical 5 liter tank. The solution flows through the tubing and is returned to the tank. The flow rate is achieved using a triplex pump equipped with a variable speed drive. 4 liters of fresh water or brine (e.g., synthetic brine or seawater) are prepared in the sample tank and the pump is started and set to deliver a flow rate of 1.5 gal / min (1 US gai = 3.78541 liters). The brine solution is recirculated until the temperature equilibrates to 25°C and a stabilized pressure differential is reached. This pressure is recorded as the initial pressure of the fresh water or seawater or brine. To evaluate the friction-reducing effect of each of the polymers 1 to 5, the flow loop tank was filled with the brine described above. The brine is then recirculated through the flow loop at a flow rate of 1.5 gahmin *. The polymer is added at a concentration of 0.05 pptg to the recirculating brine.

[0316] The polymer solution is rapidly injected with a syringe into the sample reservoir containing the fresh water or seawater or brine, and a timer is started. The pressure is recorded every second for 5 minutes. The percentage friction reduction (% FRt) at a given time 't' is calculated from the initial pressure drop APi and the pressure drop at time t, APt, using the equation:

[0317] [Math.l] AP - AP %FRt = ; p ' X 100 ' A Pj

[0318] The results of the flow loop are shown in [Fig.l].

[0319] The polymers prepared from the composition of the invention offer better performance, the friction reduction effect is faster, and the maximum %FRt is higher, making these polymers more effective than those of the prior art.

[0320] It can be seen from [Fig.l] that the more 2-dimethylaminoethyl acrylate monomers are derived from the invention, the better the performance will be. of the polymer. Example 3 - Retention agent in paper

[0321] Retention agents are polymers added to cellulose fiber pulps prior to paper formation to increase the efficiency with which fine material particles, including cellulosic fine materials, are retained in the paper product.

[0322] Type of dough used

[0323] Virgin fiber pulp:

[0324] A wet pulp is obtained by disintegrating a dry pulp to obtain a final aqueous concentration of 1% by weight. It is a neutral pH pulp consisting of 90% bleached virgin long fibers, 10% bleached virgin short fibers and 30% additional GCC (natural calcium carbonate) (Hydrocal® 55 from Omya) by weight based on the weight of the fibers.

[0325] Evaluation of total retention and charge retention

[0326] For all the following tests, the polymer solutions are prepared at 0.5% by weight. After 45 minutes of preparation, the polymer solutions are diluted 10 times before injection.

[0327] The various results are obtained using a Britt Jar type device with a stirring speed of 1000 rpm.

[0328] The sequence of the process is as follows: - T=0 s: Stirring of 500 mL of paper pulp at a concentration of 0.5% by weight. - T=10 s: Addition of the retention agent (300 g of dry polymer / ton of dry paste). - T=20 s: Elimination of the first 20 mL corresponding to the dead volume under the canvas, then recovery of 100 mL of white water.

[0329] The first pass retention percentage (%FPR), corresponding to the total retention, is calculated according to the following formula: %FPR = (CHb-Cww) / CHb*100

[0330] First pass ash retention in percentage (%FPAR) is calculated using the following formula: %FPAR = (AHB-Aww) / AHB*100 with : - CHB: Headbox consistency - Cww: Consistency of white water - Ahb: Consistency of the ash in the headbox - Aww: Consistency of white water ashes

[0331] For each of these analyses, the highest values ​​correspond to the best performances.

[0332] The same polymers as in Example 2 were tested and the results are summarized in Table 6.

[0333] Evaluation of gravity drainage performance using the “Canadian Standard Freeness (CSF) »

[0334] In a beaker, the pulp is processed at a stirring speed of 1000 rpm.

[0335] The sequence of the process is as follows: - T=0 s: Stirring of 500 mL of paper pulp at a concentration of 0.6% by weight. - T=10 s: Addition of the retention agent (300 g of dry polymer / ton of dry paste). - T=20 s: Stop stirring and add the necessary quantity of water to obtain 1 liter.

[0336] This liter of paste is transferred into the “Canadian Standard Freeness Tester” and the TAPPI T227om-99 procedure is applied.

[0337] The volume, expressed in mL, recovered by the lateral tubule gives a measure of gravity drainage. The higher the value, the better the gravity drainage.

[0338] This performance can also be expressed by calculating the percentage improvement over blank (% CSF).

[0339] Higher values ​​correspond to better performance.

[0340] The same polymers as in Example 2 were tested and the results are summarized in Table 6.

[0341] [Tableauxô] Polymer %FPAR %FPR %CSF I reference <22.3 65.4 - 2 invention ri ri 66.6 5.2 3 lavention 27.5 67.9 10.9 4 Hiveni ion 29.1 70.2 15.1 5 invention 34.6 79.7 25.9

[0342] The polymers of the invention provide better performance as a retention agent for paper.

[0343] Regarding CSF, a polymer prepared with only 2-dimethylaminoethyl acrylate monomers according to the invention improves performance by more than 25%.

[0344] The more 2-dimethylaminoethyl acrylate monomers are derived from the invention, the better the performance of the polymer will be.

Claims

Claims

1. Water-soluble polymer obtained by polymerization of at least one 2-dimethylaminoethyl acrylate monomer and / or its salts, in the presence of at least one tocopherol and / or its derivatives, or of a tocotrienol and / or its derivatives.

2. Water-soluble polymer according to claim 1, said water-soluble polymer being obtained by polymerization of at least one 2-dimethylaminoethyl acrylate monomer and / or its salts in the presence of at least one α-tocopherol.

3. A water-soluble polymer according to any preceding claim, wherein the amount of tocopherol and / or its derivatives or tocotrienol and / or its derivatives is between 1 ppm and 10,000 ppm, based on the amount of 2-dimethylaminoethyl acrylate monomer and / or its salts.

4. A water-soluble polymer according to any preceding claim, wherein tocopherol and / or its derivatives, or tocotrienol and / or its derivatives, is / are added to the 2-dimethylaminoethyl acrylate monomer and / or its salts after the synthesis of said 2-dimethylaminoethyl acrylate monomer and / or its salts.

5. A water-soluble polymer according to any preceding claim, wherein tocopherol and / or its derivatives, or tocotrienol and / or its derivatives, is / are added to the 2-dimethylaminoethyl acrylate monomer and / or its salts before storage of said 2-dimethylaminoethyl acrylate monomers and / or their salts.

6. A water-soluble polymer according to any preceding claim, wherein the 2-dimethylaminoethyl acrylate monomer is quaternized with methyl chloride.

7. A water-soluble polymer according to any preceding claim, wherein the water-soluble polymer comprises at least 1 mol% of 2-dimethylaminoethyl acrylate monomer and / or its salts based on the total number of moles of monomers.

8. A water-soluble polymer according to any preceding claim, wherein the water-soluble polymer has a weight-average molecular weight of between 50,000 g / mol and 30,000,000 g / mol.

9. Composition comprising: • from 1 to 99.9999% by weight of at least one 2-dimethylaminoethyl acrylate monomer and / or its salts; • from 1 to 10,000 ppm of at least one tocopherol and / or its derivatives, or of one tocotrienol and / or its derivatives, based on the amount of 2-dimethylaminoethyl acrylate monomer and / or its salts, • optionally at least one additive chosen from biocides, polymerization inhibitors, moisture absorbers, color stabilizers.

10. Composition according to claim 9, comprising at least one color stabilizer chosen from: niacinamide, retinol, 3-tert-butyl-4-hydroxyanisole (3-BHA), 2-tert-butyl-4-hydroxyanisole and 2,6,-di-tert-butyl-4-methylphenol.

11. A composition according to claim 9 or claim 10, wherein the weight ratio of tocopherol and / or its derivatives or tocotrienol and / or its derivatives to the color stabilizer is between 1 and 100.

12. Use of the water-soluble polymer according to claim 1 in water treatment, sludge dewatering, a papermaking process, agriculture, a cosmetic composition, a detergent composition, a textile process, an oil and gas exploitation process.

13. Use of the water-soluble polymer according to claim 1 as a dispersant, coagulant, flocculant, thickener, grinding agent, friction reducer, superabsorbent, retention agent.

14. A process for inhibiting the formation of vinyl acrylate resulting from a reaction between at least one 2-dimethylaminoethyl acrylate monomer and / or its salts and oxygen, comprising a mixture of said 2-dimethylaminoethyl acrylate monomer and / or its salts with a tocopherol and / or its derivatives, or a tocotrienol and / or its derivatives.

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