Process for producing aminoundecanoic acid and aminodecanoic acid

Abstract

The present invention is mainly directed to a method for producing an aminocarboxylic acid represented by the following formula (I): NH3-CH2-(CH2) n -COOH (I) (wherein n is an integer of 7 to 12) (i) a compound represented by the following formula (II): CH=CH-(CH2) n-1 -COOH(II) with hydrogen bromide (HBr) to form a compound of formula (III): Br-CH2-(CH2) n -COOH (III) forming an ω-bromoalkanoic acid of (ii) reacting the resulting ω-bromoalkanoic acid of formula (III) with ammonia in an aqueous solution to form a reaction mixture comprising an aminocarboxylic acid of formula (I) and ammonium bromide; (iii) separating the reaction mixture of the aminocarboxylic acid of formula (I) with the aqueous solution rich in ammonium bromide; (iv) contacting the resulting ammonium bromide-rich aqueous solution with sodium hydroxide to form ammonia and a sodium bromide-rich aqueous solution; (v) purifying the resulting sodium bromide-rich aqueous solution to remove organic impurities; (vi) contacting the resulting purified sodium bromide-rich aqueous solution with chlorine to form a bromine and sodium chloride-rich aqueous solution; (vii) reacting the resulting bromine with hydrogen to form hydrogen bromide; and (viii) recycling the obtained hydrogen bromide to step (i) The present invention relates to a method, comprising: The present invention also relates to a method for producing polyamides or copolyamides from said aminocarboxylic acids.

Description

Technical Field

[0001] This patent application relates to a method for producing aminocarboxylic acids, particularly 10-aminodecanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. It also relates to a method for producing polyamides or copolyamides from said aminocarboxylic acids.

Background Art

[0002] Aminocarboxylic acids such as 10-decanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid are monomers particularly used in the production of long-chain polyamides such as polyamide 10, polyamide 11, and polyamide 12.

[0003] The excellent thermal and mechanical properties of these polyamides, as well as their chemical resistance, make them advantageous for various applications, particularly in the automotive, sports goods, coating, or 3D printing fields. One increasingly important advantage of these polyamides is the fact that their monomers can be obtained from plant-derived products and are thus renewable.

[0004] Thus, 11-aminoundecanoic acid can be obtained from castor oil by transesterification in the presence of methanol and subsequent pyrolysis. The resulting methyl 10-undecenoate can be hydrolyzed to 10-undecenoic acid, which can be brominated at the chain end by a hydrobromination process. The resulting 11-bromoundecanoic acid (or ω-bromoundecanoic acid) can then be subjected to an ammonolysis step by reaction with ammonia to obtain 11-aminoundecanoic acid and ammonium bromide.

[0005] The hydrobromination process is described, for example, in French Patent No. 928265. Hydrobromic acid is made to act on 10-undecenoic acid in a solution of an organic solvent in the presence of a catalyst such as benzoyl peroxide.

[0006] French Patent No. 951932 proposes to increase the yield of 11-bromoundecanoic acid to about 80% using excess hydrobromic acid and a hydrocarbon solvent such as benzene, toluene, petroleum ether or chlorinated hydrocarbon.

[0007] According to European Patent No. 3,030,543, the reaction is carried out in two steps. The first step consists of mixing 10-undecenoic acid and hydrobromic acid in the form of a turbulent liquid flow in a first reactor, and the second step consists of continuing the reaction in a second reactor in a transitional or laminar flow. In this case, it is also possible to use other solvents.

[0008] French Patent Application No. 928265 and European Patent No. 235866 describe the conversion of 11-bromoundecanoic acid to 11-aminoundecanoic acid by treatment with an aqueous solution of ammonium hydroxide. The formed 11-aminoundecanoic acid is separated from the formed ammonium bromide.

[0009] International Publication No. 2018 / 080869 pamphlet describes the synthesis of 10-aminodecanoic acid from 9-decenoic acid obtained from palm oil compositions. In particular, the hydrobromic acid chlorination of 9-decenoic acid is carried out by bubbling gaseous hydrobromic acid into a solution of 9-decenoic acid in toluene in the presence of benzoyl peroxide at a temperature of 5 °C to 15 °C. After washing, drying and purification with hexane, the yield of 10-bromodecanoic acid is 64%. 10-bromodecanoic acid can react with 28% ammonium hydroxide at room temperature and then at 45 °C to form 10-aminodecanoic acid, which is recovered by crystallization at room temperature, followed by filtration, washing and drying.

[0010] It is known to those skilled in the art that 11-dodecenoic acid produced from 10-undecenoic acid can react with hydrobromic acid in the presence of benzoyl hydroperoxide to obtain 12-bromododecanoic acid in a yield of 88% (see Chemistry&Industry (London) 1954, 190-191).

[0011] All these methods require a significant amount of hydrogen bromide, which is generally generated in situ by the expensive reaction of bromine and hydrogen, and have the disadvantage of producing effluents containing large amounts of salts.

[0012] It is known to convert ammonium bromide obtained in the ammonolysis step to hydrogen bromide, to sodium bromide, then to bromine, and then to react with hydrogen (see Kunststoff Handbuch, Polyamide, 3 / 4, published by L. Bottenbruch and R. Binsack, Hanser Fachbuchverlag 1998, pp. 646 - 648).

[0013] Although there have been improvements, there is still a need to improve this method. In particular, low yields are observed for the conversion of sodium bromide to bromine, and fouling is observed during the conversion of the thus - obtained bromine to hydrogen bromide. SUMMARY OF THE INVENTION

[0014] Accordingly, an object of the present invention is to propose a method for producing aminocarboxylic acids, particularly 12 - aminododecanoic acid, 11 - aminoundecanoic acid, and 10 - aminodecanoic acid, which is more economical and enables reduction of the amount of effluents.

[0015] Specifically, the present invention is based on the observation that by substituting part of the bromine with chlorine, it is possible to reduce the amount of bromine required for the method and the amount of bromide discharged into the environment.

[0016] Furthermore, it has been found that by a step of purifying sodium bromide before conversion to bromine, fouling of the reactor can be substantially reduced during the conversion to hydrogen bromide.

[0017] Accordingly, according to a first aspect, one subject of the present invention is a method for producing an aminocarboxylic acid of the following formula (I), NH3 - CH2 - (CH2) n-COOH (I) (wherein n is an integer of 7 to 12, preferably 8 to 10.) The following steps: (i) The following formula (II) CH=CH-(CH2) n-1 -COOH (II) The unsaturated carboxylic acid is reacted with hydrogen bromide (HBr) to form the following formula (III) Br-CH2-(CH2) n -COOH (III) The step of forming ω-bromoalkanoic acid, (ii) The ω-bromoalkanoic acid of formula (III) obtained is reacted with ammonia in an aqueous solution to form a reaction mixture containing the aminocarboxylic acid of formula (I) and ammonium bromide, (iii) The step of separating the reaction mixture of the aminocarboxylic acid of formula (I) and the aqueous solution rich in ammonium bromide, (iv) The obtained aqueous solution rich in ammonium bromide is brought into contact with sodium hydroxide to form ammonia and an aqueous solution rich in sodium bromide, (v) The step of purifying the obtained aqueous solution rich in sodium bromide to remove organic impurities, (vi) The obtained purified aqueous solution rich in sodium bromide is brought into contact with chlorine to form bromine and an aqueous solution rich in sodium chloride, (vii) The step of reacting the obtained bromine with hydrogen to form hydrogen bromide, and (viii) The step of recycling the obtained hydrogen bromide to step (i) is a method comprising.

[0018] According to one embodiment, bromides derived from another method are added to the solution rich in ammonium bromide or sodium bromide in step (iv). According to another embodiment, bromine derived from another method is added to the bromine obtained in step (vi).

[0019] According to one embodiment, step (v) of purifying the aqueous solution of bromide enables a five-fold ultra-reduction of TOC (total organic carbon). According to another embodiment, step (vi) is carried out using a bromide solution having a TOC of less than 2%, preferably less than 1%, and more preferably less than 0.5%.

[0020] According to a first embodiment of the method which is the subject of the present invention, step (v) is carried out by acidifying the aqueous solution rich in sodium bromide obtained from step (iv), followed by decantation of the oily phase formed. Preferably, the aqueous solution rich in sodium bromide resulting from step (iv) is acidified by adding an acid to a pH between 3 and 5. Advantageously, step (v) includes a subsequent step (va) in which the oily phase formed in step (v) is subjected to an extraction operation to obtain an aqueous solution enriched with sodium bromide, which is again fed to step (iv) or (vi). Advantageously, the operation enabling the extraction of the aqueous solution enriched with sodium bromide in step (va) is liquid / liquid extraction.

[0021] According to a second embodiment of the method which is the subject of the present invention, step (v) is carried out by neutralizing the aqueous solution rich in sodium bromide followed by liquid / liquid extraction. Preferably, the aqueous solution rich in sodium bromide is neutralized to a pH between 3 and 10 in step (v). Advantageously, the neutralization in step (v) is carried out by adding an aqueous solution of hydrochloric acid, hydrobromic acid, sulfuric acid or a mixture thereof.

[0022] According to a third embodiment of the method which is the subject of the present invention, step (v) is carried out by adsorption onto an adsorbent material. Preferably, the adsorbent material is selected from adsorbent materials, in particular mineral materials such as activated carbon, silica or alumina or mixtures thereof, organic materials such as adsorbent macro-crosslinked resins or ion exchange resins, for step (v).

[0023] According to a fourth embodiment of the method which is the subject of the present invention, step (v) is carried out by membrane separation to form a permeate enriched in sodium bromide and depleted in organic impurities and a concentrate depleted in sodium bromide and enriched in organic impurities. Step (v) can in particular be carried out by means of one or more nanofiltration membranes. Advantageously, step (v) includes a subsequent step (va') in which the concentrate obtained in step (v), depleted in sodium bromide and enriched in organic impurities, is subjected to a diafiltration step in order to recover an aqueous solution enriched in sodium bromide and depleted in organic impurities, and this solution can be mixed with the permeate obtained from step (v). Furthermore, step (v) can include a subsequent step (vb) in which the permeate obtained in step (v), enriched in sodium bromide and depleted in organic impurities, and, where appropriate, the aqueous solution enriched in sodium bromide and depleted in organic impurities resulting from step (va') are subjected to a second membrane separation step.

[0024] According to another aspect, the invention also relates to a claim for a method for producing a polyamide or copolyamide from said aminocarboxylic acid.

Embodiments for Carrying Out the Invention

[0025] Definition of Terms The term "bromide" is generally understood to denote bromide salts, in particular alkali metal bromides such as sodium bromide or potassium bromide, ammonium bromide, or compounds containing bromine atoms in the (-I) oxidation state lacking a carbon-hydrogen bond, such as hydrogen bromide or hydrobromic acid.

[0026] As mentioned above, the object of the present invention is to improve the economics of a method for producing an aminocarboxylic acid such as 12-aminododecanoic acid, 11-aminoundecanoic acid or 10-aminodecanoic acid by reducing or even preventing the supply and fouling of bromine during the conversion of the bromine thus obtained into hydrogen bromide.

[0027] According to the present invention, a method for producing an aminocarboxylic acid of the following formula (I), comprising the following, NH3-CH2-(CH2)n -COOH (I) (wherein n is an integer of 7 to 12, preferably 8 to 10.) (i) The following formula (II) CH=CH-(CH2) n-1 -COOH (II) The unsaturated carboxylic acid is reacted with hydrogen bromide (HBr) to form the following formula (III) Br-CH2-(CH2) n -COOH (III) to form ω-bromoalkanoic acid, (ii) reacting the obtained ω-bromoalkanoic acid of formula (III) with ammonia in an aqueous solution to form a reaction mixture containing the amino carboxylic acid of formula (I) and ammonium bromide, (iii) separating the reaction mixture of the amino carboxylic acid of formula (I) and the aqueous solution rich in ammonium bromide, (iv) contacting the obtained aqueous solution rich in ammonium bromide with sodium hydroxide to form ammonia and an aqueous solution rich in sodium bromide, (v) purifying the obtained aqueous solution rich in sodium bromide to remove organic impurities, (vi) contacting the obtained purified aqueous solution rich in sodium bromide with chlorine to form bromine and an aqueous solution rich in sodium chloride, (vii) reacting the obtained bromine with hydrogen to form hydrogen bromide, and (viii) recycling the obtained hydrogen bromide to step (i) A method comprising

[0028] As described above, a certain number of unsaturated carboxylic acids of formula (II) such as 11-dodecenoic acid, 10-undecenoic acid, and 9-decenoic acid used in the method can be obtained from renewable sources such as vegetable oils.

[0029] 10-Undecenoic acid can be reduced to undecenol, then converted to undecenyl bromide, then treated with sodium cyanide, and the resulting nitrile hydrolyzed to obtain 11-dodecenoic acid.

[0030] 10-Undecenoic acid can be obtained from castor oil by the following steps for forming methyl ricinoleate: methanolysis, pyrolysis to methyl 10-undecenoate and heptanal, and then hydrolysis of methyl 10-undecenoate. 10-Undecenoic acid can also be obtained by pyrolysis of ricinoleic acid obtained by hydrolysis of castor oil. Methyl ricinoleate can also be obtained by reactive grinding of castor seeds.

[0031] 9-Decenoic acid can be obtained from esters of fatty acids derived from natural oils, for example, by reaction with an α-olefin in the presence of a catalyst and hydrolysis of the resulting ester of 9-decenoic acid to 9-decenoic acid, as described in WO 2018 / 080869.

[0032] Step (i) The reaction of an unsaturated carboxylic acid of formula (II) with hydrogen bromide (HBr) according to step (i) of the process of the invention to form an ω-bromoalkanoic acid of formula (III) is known to those skilled in the art and is described, for example, in French Patent No. 951,932, US Patent No. 2,772,302, European Patent 3,030,543, Chinese Patent No. 103,804,209, or WO 2018 / 080869.

[0033] The unsaturated carboxylic acid of formula (II) is preferably used in liquid form and is in particular melted or dissolved in a solvent or a mixture of solvents.

[0034] HBr can be in gaseous or liquid form, for example, it can be liquefied under saturated vapor pressure and can be in solution in a solvent or a mixture of solvents.

[0035] When the solvent is used in the process of the present invention, the solvent is preferably selected from benzene, fluorobenzene, chlorobenzene, toluene, α,α,α-trifluorotoluene, ethylbenzene, xylene, cyclohexane, methylcyclohexane, methylcyclopentane, n-hexane, 2-methylhexane, 3-methylhexane, n-heptane, isooctane, tetrachloroethylene, 1,1,1-trichloroethane, dibromomethane, trichloromethane, tetrachloromethane, 1-bromopropane, dimethyl carbonate, tetrahydrofuran (THF), 1,4-dioxane, 2-methyltetrahydrofuran, tetrahydropyran (THP), 1-propoxypropane, 1-ethoxybutane, 2-isopropoxypropane, acetonitrile, and mixtures thereof.

[0036] Advantageously, any solvent is heated to a temperature in the range of -50 °C to 30 °C, preferably -40 °C to 10 °C, preferably -30 °C to 0 °C, preferably -30 °C to -10 °C.

[0037] The reaction is generally carried out with an excess molar amount of HBr relative to the unsaturated carboxylic acid of formula (II).

[0038] The reaction is usually carried out in the presence of a radical initiator. The radical initiator can be a radical generator selected particularly from oxygen or oxygen-containing gases such as air or oxygen-enriched air, peroxides such as benzoyl peroxide, or UV irradiation. Oxygen or oxygen-containing gases are particularly preferred due to the ease of their industrial processing, their stability, and their low cost compared to other types of initiators.

[0039] The hydrobromination may be carried out in a homogeneous liquid medium or in a liquid-gas phase.

[0040] The reaction can be carried out in a packed column reactor, a stirred reactor or a tubular reactor.

[0041] The reaction mixture leaving the reactor may be subjected to evaporation of excess HBr or washed with water to remove residual HBr. After evaporating any solvent and purifying if necessary, ω-bromoalkanoic acid of formula (III) is obtained.

[0042] Steps (ii) and (iii) In step (ii) of the process of the present invention, the ω-bromoalkanoic acid of formula (III) thus obtained is reacted with ammonia, and this step is called an ammonolysis step. Step (iii) of the process of the present invention consists of separating the aminocarboxylic acid of formula (I) formed from the reaction mixture. The separation can be carried out, in particular, by solid-liquid separation. The product is then purified, in particular, by washing with water or an aqueous solution. In this way, an aqueous solution rich in ammonium bromide is obtained.

[0043] These steps (ii) and (iii) are known to those skilled in the art and are described, for example, in French Patent No. 928,265, French Patent No. 958,178, Chinese Patent No. 1,078,585, Chinese Patent No. 103,804,209 or International Publication No. 18 / 080,869 pamphlet.

[0044] It is possible to use liquid ammonia or ammonium hydroxide in an aqueous, alcoholic or aqueous-alcoholic solution. The reaction can be carried out at a low temperature, for example room temperature or 30 °C, or at a higher temperature, for example 80 °C. Depending on the temperature selected, the reaction time can vary between about 5 hours and 120 hours, and the yield is lower at higher temperatures. Advantageously, the reaction medium is subjected to a regular temperature increase between an initial temperature of 15 °C to 25 °C and a final temperature of 26 °C to 40 °C. The pressure can be atmospheric pressure or a pressure close thereto.

[0045] The ammonolysis reaction can be carried out in a stirred reactor or in a battery of 2 to 25 stirred reactors in series or in parallel.

[0046] The formed aminocarboxylic acid of formula (I) can be separated from the reaction mixture, for example, by the following steps. The reaction mixture is diluted with water and heated to boiling. The ammonia released is recovered in water to form an ammonium hydroxide solution, which can be reused, especially to supply the ammonia used in step (ii). Then, before cooling, the mixture is separated from any oil layer formed by hot decantation to separate 12-aminododecanoic acid, 11-aminoundecanoic acid or 10-aminodecanoic acid by crystallization. The solid is discharged, washed with water and optionally recrystallized with boiling water.

[0047] The mother liquor collected during the separation and purification of the target product contains ammonium bromide and constitutes an ammonium bromide-rich solution that is subsequently treated in the process of the present invention.

[0048] The aminocarboxylic acid of formula (I) can also be separated from the ammonolysis reaction mixture by solid-liquid separation such as filtration through a filter or draining. The recovered mother liquor can be subjected to liquid-liquid extraction, crystallization and / or filtration to form an ammonium bromide-rich aqueous solution depleted of the aminocarboxylic acid of formula (I).

[0049] Step (iv) In step (iv), an ammonium bromide-rich aqueous solution formed from the mother liquor obtained in the previous step is reacted with sodium hydroxide to convert ammonium bromide to sodium bromide and generate ammonia in gaseous form.

[0050] This reaction can be carried out, for example, in a stirred reactor or a packed column.

[0051] The amount of sodium hydroxide added is preferably approximately stoichiometric with respect to the amount of ammonium ions. Very satisfactory results are obtained when sodium hydroxide is added in a molar ratio of 1:0.8 to 1:1.25 with respect to the ammonium ion content in the solution. Advantageously, the amount of sodium hydroxide added in this step is a stoichiometric amount or a slightly excessive amount, for example, a molar ratio of 1:1.0 to 1:1.1 with respect to the ammonium ion content in the solution.

[0052] Sodium hydroxide may be added in solid form or in the form of a solution, especially an aqueous solution. Advantageously, a concentrated aqueous solution of sodium hydroxide is used to reduce water consumption. It is particularly useful to use sodium hydroxide in the form of a solution having a content of 2 to 20 mol / l, especially 6 to 11 mol / l.

[0053] To promote the evaporation of ammonia, the reaction mixture can be brought to a higher temperature. Preferably, the reaction mixture is heated to a temperature of 50 °C to 150 °C, advantageously 80 °C to 130 °C, more preferably 95 °C to 110 °C, to evaporate a part of ammonia and water. The evaporation of ammonia makes it possible to prevent the formation of potentially troublesome by-products in subsequent steps of the process.

[0054] The ammonia generated is preferably reused in step (ii) either as it is or after being dissolved in water.

[0055] The aqueous solution rich in sodium bromide recovered generally has a pH of 9 to 13, preferably 9.5 to 11.5.

[0056] Step (v) In this step, the aqueous solution rich in sodium bromide obtained in the previous step is subjected to one or more purification steps to remove organic impurities. These impurities form a complex mixture and their content can be characterized by total organic carbon (TOC).

[0057] The fact that organic impurities are removed from an aqueous solution rich in sodium bromide enables step (vi) to be carried out without fouling by soot, which is very harmful to the operation of such a method.

[0058] The organic impurities present in the sodium bromide solution can be removed, in particular, by liquid-liquid extraction, adsorption or membrane separation in an acidified, acidic or neutral medium, or by any combination of these methods. Four embodiments A to D of step (v) are described in more detail below.

[0059] Step (v) Variant A: Acidification followed by decantation In this variant, the sodium bromide solution obtained from step (iv) is acidified by adding an acid to a pH of less than 5. Then, a less dense oily phase is formed that can be easily separated, for example, by decantation.

[0060] The sodium bromide-rich solution resulting from step (iv) can be acidified by adding an aqueous solution of a strong mineral acid, such as hydrochloric acid, hydrobromic acid or sulfuric acid, alone or as a mixture. Preferably, the acid solution rich in sodium bromide has a pH of from 3 to 5, preferably from 3 to 4.5.

[0061] The formation of an oily phase rich in organic impurities is observed, and this phase is less dense than the aqueous solution rich in sodium bromide. The oily phase can be separated by means known per se, such as by decantation. This decantation may be carried out, for example, in a static decanter or a centrifugal decanter. Then, the purified aqueous solution rich in sodium bromide depleted of organic compounds can be subjected to step (vi) after, optionally, one or more additional purification steps according to one of variants A to D.

[0062] The formed oily phase can be removed directly or subjected in advance to one or more bromide extraction steps to recover the aqueous phase containing bromide and to be reused in step (v) or step (vi) while removing the oily phase containing organic impurities.

[0063] According to one embodiment, in order to extract more bromide, the oil phase can be subjected to liquid-liquid extraction with, for example, a concentrated aqueous saline solution. Extraction with a sodium chloride solution, preferably such a solution having a concentration of 1 mol / l to 6 mol / l, is particularly preferred. The bromide-containing aqueous phase is recovered and reused in step (v) or step (vi), and the oil phase is recovered and removed.

[0064] As a modification, the extraction of bromide from the oil phase can be carried out by mixing with water and a water-immiscible liquid carboxylic acid and decantation. Such immiscible carboxylic acids can include heptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, fatty acids containing 10 to 12 carbon atoms, or mixtures of such acids. It is also possible to use distillation residues (light and heavy) of heptanoic acid or octanoic acid or 2-ethylhexanoic acid or nonanoic acid, preferably such residues containing at least 30%, preferably at least 50% of heptanoic acid, octanoic acid, 2-ethylhexanoic acid or nonanoic acid.

[0065] The weight ratio of the oil phase / water / carboxylic acid can vary from 1:0.3:0.3 to 1:3:2. This extraction is generally carried out between room temperature and 130°C, preferably between 50°C and 100°C.

[0066] The extraction can be carried out, for example, in a stirred reactor in a step of contacting by vigorously mixing. A static mixer can also be used. An oil phase depleted of bromide and an aqueous solution enriched with bromide are obtained, and these phases can be separated by conventional liquid-liquid separation means, such as decantation, carried out in a reactor or a decanter.

[0067] Alternatively, - injection of water into the upper part of the column, - injection of the carboxylic acid and the oil phase into the lower part of the column, - withdrawing the aqueous phase at the lower part of the column, and - withdrawing the oil phase at the upper part of the column This enables extraction to be carried out using a continuous liquid-liquid extraction column.

[0068] The obtained purified aqueous solution rich in sodium bromide may be subjected to step (v) or step (vi) after one or more additional purification steps according to any one of Modifications A to D, optionally.

[0069] According to another embodiment, the extraction of bromide from the oily phase can be carried out by a process of dilution with water or an aqueous sodium hydroxide solution and diafiltration by membrane separation. At the outlet of the diafiltration, a stream enriched in organic impurities and depleted in sodium bromide, and an aqueous phase enriched in bromide and depleted in organic impurities are obtained. The stream enriched in organic impurities and depleted in bromide can be removed. The aqueous phase enriched in bromide and depleted in organic impurities may be subjected to step (v) or step (vi).

[0070] The membranes and procedures used are described in Modification D below.

[0071] Advantageously, the pH of the mixture can be adjusted to above 7, preferably from 8 to 11, more preferably from 9 to 10, before being subjected to the membrane.

[0072] Step (v) Modification B: Liquid-liquid extraction In this modification, the aqueous solution rich in sodium bromide obtained from step (iv) is neutralized and then directly subjected to liquid-liquid extraction without prior decantation.

[0073] The aqueous solution rich in sodium bromide obtained from step (iv) can be neutralized by adding an aqueous solution of a strong mineral acid such as hydrochloric acid, hydrobromic acid or sulfuric acid, alone or as a mixture. Preferably, the neutralized solution rich in sodium bromide has a pH of from 3 to 10, preferably from 4 to 10.

[0074] Next, an aqueous solution rich in sodium bromide can be directly subjected to liquid-liquid extraction as described above. In particular, the solution rich in sodium bromide may be mixed with a water-immiscible carboxylic acid as described above. The formed oily phase can be separated by a conventional method, for example, by decantation.

[0075] Liquid-liquid extraction can also be carried out in a stirred reactor or in a continuous liquid-liquid extraction column, - injection of the solution rich in sodium bromide into the upper part of the column, - injection of the carboxylic acid into the lower part of the column, - withdrawing the purified aqueous solution rich in sodium bromide at the lower part of the column, and - withdrawing the oily phase at the upper part of the column can be carried out by.

[0076] The formed oily phase is either removed directly or subjected to one or more additional bromide extraction steps beforehand.

[0077] The obtained purified aqueous solution rich in sodium bromide can undergo a steam stripping step to remove volatile organic impurities. This steam stripping step can be carried out in a stirred reactor or a column.

[0078] The obtained purified aqueous solution rich in sodium bromide may be subjected to step (vi) after, optionally, one or more additional purification steps according to one of Variants A to D.

[0079] Step (v) Variant C: Adsorption In this variant, the aqueous solution rich in sodium bromide obtained from step (iv) is purified by contacting it with an adsorbent.

[0080] Suitable adsorbents can in particular be activated carbon, macroreticular adsorbent resins, ion exchange resins or mixtures of ion exchange retardants, silica-type, alumina-type or silica-alumina-type adsorbents.

[0081] The contact is carried out in one or more columns or in a stirred reactor and can subsequently be subjected to solid-liquid separation. Advantageously, the contact is carried out in several consecutive columns in which the solid is stationary and the liquid passes through the bed of the solid. When the adsorbent is saturated, the bromide-rich aqueous solution may be fed to another reactor or to one or more other columns containing fresh adsorbent. The saturated adsorbent may be discharged and removed or, where appropriate, regenerated.

[0082] The adsorbent can be regenerated by conventional methods, for example by washing with water, washing with a water-miscible solvent and then washing again with water. The organic impurities extracted from the adsorbent and the solvent carrying water can be regenerated by distillation and reused. Examples of solvents include methanol, ethanol, dimethyl sulfoxide, acetic acid, propanoic acid and the like.

[0083] Before the adsorption step, the pH of the aqueous sodium bromide solution can be adjusted to a pH within the optimal range of the effectiveness of the adsorbent, for example by addition of an acid as described above in the upper section, in particular between 4 and 11, preferably between 8 and 10.5.

[0084] The resulting purified aqueous solution rich in sodium bromide may be fed to step (vi) optionally after one or more additional purification steps according to one of Variants A - D.

[0085] Step (v) Variant D: Membrane separation In this variant, the bromide-rich aqueous solution obtained from step (iv) is purified by membrane separation.

[0086] The membrane separation can be carried out, for example, by nanofiltration, pervaporation or reverse osmosis.

[0087] The membrane may be made of ceramic, glass or metal, composites, or crosslinked or non-crosslinked polymers, or may be mixed (inorganic or organic). Particular preference is given to membranes made of polyamide, such as the MPS-34 nanofiltration membrane sold by Koch Membrane Systems.

[0088] The membrane can be operated in continuous, semi - continuous or batch mode. The flow can be either frontal or tangential to the filter.

[0089] An aqueous solution rich in sodium bromide is fed to the membrane, which makes it possible to separate a first stream depleted in organic impurities from a second stream rich in organic impurities.

[0090] To further increase the recovery rate of bromide, the stream enriched in organic impurities can then be subjected to a diafiltration step by dilution in water and membrane separation. At the outlet of the diafiltration, a stream enriched in organic impurities and depleted in sodium bromide, and a stream enriched in bromide and depleted in organic impurities are obtained. The stream enriched in organic impurities and depleted in bromide can be removed. The stream enriched in bromide and depleted in organic impurities can be mixed with the first stream of bromide depleted in organic impurities.

[0091] Before passing through the membrane, the pH of the aqueous solution rich in sodium bromide can be adjusted to a pH greater than 7, preferably from 8 to 11, more preferably from 9 to 10, for example, by the addition of a base such as sodium hydroxide or an acid as described above, in order to optimize the effectiveness of the membrane with respect to separation and lifespan.

[0092] As a variant, the stream enriched in organic impurities can be subjected to a bromide extraction step by one or more of the steps described in the above Variants A - C instead of the diafiltration step.

[0093] The purified aqueous solution obtained after membrane separation can then be sent to step (vi) optionally after one or more additional purification steps by one of Variants A - D.

[0094] Step (vi) This step aims to convert the bromide in the purified aqueous solution rich in sodium bromide obtained in the previous step into bromine. This step is carried out by reacting the aqueous solution with chlorine to obtain an aqueous solution rich in bromine and sodium chloride.

[0095] This step can be carried out, for example, in a column containing a filler, - injection of the purified aqueous sodium bromide solution obtained from step (v) to the top of the column, - injection of chlorine to the lower quarter of the column, - injection of steam at the bottom of the column to heat the bottom of the column to a temperature of 70 °C to 100 °C, preferably 90 °C to 100 °C, - step of taking out a stream mainly composed of sodium chloride and water at the bottom of the column, - recovery of bromine at the top of the column and can be carried out together.

[0096] Advantageously, the aqueous sodium bromide solution contains less than 2%, preferably less than 1%, more preferably less than 0.5% of total organic carbon (TOC). Specifically, it has been observed that such a concentration makes it possible to limit the loss of bromide at the bottom of the column.

[0097] The flow rate of chlorine is advantageously adjusted to ensure a stoichiometric amount with respect to the bromide injected, preferably 0 to 30%, more preferably 5% to 20% excess moles.

[0098] Step (vii) This step aims to react the obtained bromine with hydrogen to form hydrogen bromide. This step is known to those skilled in the art and is described, for example, on page 82 of "Bromine and its compounds" (London 1966) published by Z.E. Jolles, US Patent No. 2,070,263, or "Bromine" (2015) published from Wiley Ullmann’s Encyclopedia of Industrial Chemistry.

[0099] More specifically, this step can be carried out by condensing the bromine recovered at the upper part of the column in the previous step and injecting it in vaporized form into the tubular reactor in co-current flow with hydrogen heated to a high temperature, for example 500 °C to 1000 °C.

[0100] Accordingly, hydrogen bromide that is partially or even fully generated from the recycling of the bromide produced by the method is recovered.

[0101] When the TOC contained in the aqueous bromide solution entering step (v) is lower, it has been found that the fouling of the hydrogen bromide synthesis reactor in the form of soot is proportionally less.

[0102] Step (vii) This step aims to recycle the hydrogen bromide obtained in the previous step to step (i).

[0103] The formed hydrogen bromide is cooled and can be reused in the hydrobromination step described in Example 1.

[0104] In a specific embodiment of this method, the amount of hydrogen bromide recovered in step (vii) is less than the amount of hydrogen bromide injected in step (i). The composition of the bromine element can be carried out at various times of the method, particularly in the form of bromine in step (vi), or in the form of bromide in step (iv) or (v) or A, B, C or D, so that the generated hydrogen bromide is at least equal to the amount of hydrogen bromide required in step (i).

[0105] According to a specific embodiment, the aminocarboxylic acid of formula (I) obtained in step (iii) may undergo additional purification steps such as dissolution, subsequent liquid-liquid extraction, adsorption, recrystallization, drying, etc.

[0106] Optionally, the aminocarboxylic acid thus purified may be polymerized to the corresponding polyamide, for example by polycondensation. Alternatively, it may be used together with other monomers such as polyethers for the production of the corresponding copolymers.

[0107] The present invention will be described in more detail in the following examples.

Example

[0108] Measurement of total organic carbon (TOC) Total organic carbon is assayed by the difference between the total carbon measured by catalytic combustion at 680 °C using infrared detection by a Shimadzu TOC meter and the inorganic carbon measured by acidification with 2N hydrochloric acid and infrared detection.

[0109] Measurement of bromine loss at the bottom of the bromine synthesis column Bromine loss in the bromine synthesis process is quantified by correlating the flow rate of bromide in the brine stream at the bottom of the column with the flow rate of bromide injected into the column. The flow rate of bromide is calculated from the product of the mass flow rate of the stream and the mass concentration of bromide measured by silver salt measurement according to the following protocol: diluting the solution to be titrated with distilled water acidified with drops of nitric acid and then titrating with an aqueous silver nitrate solution (0.1 mol / l) using a Mettler titrator equipped with a DMi141-SC electrode.

[0110] Fouling of the hydrogen bromide synthesis reactor The formation of soot in the hydrogen bromide synthesis reactor is detected by qualitative visual observation after operating the tubular reactor for one day.

[0111] Example 1: Preparation of 11-bromoundecanoic acid by hydrobromination of 10-undecenoic acid A benzene / toluene solvent mixture with a volume ratio of 50 / 50 is continuously fed to the top of an absorption column cooled to -20 °C, and gaseous hydrogen bromide is injected at the bottom.

[0112] The hydrogen bromide and solvent stream recovered at the bottom of the column is mixed with a stream of oxygen and contacted with a stream of 10-undecenoic acid at 50 °C in a T-shaped mixing device connected to a PFA pipe.

[0113] The weight ratios of the flow rates of the solvent, hydrogen bromide, oxygen, and 10-undecenoic acid are 6.3 / 0.49 / 0.0028 / 1. The volume of the pipe corresponds to a residence time of 0.4 minutes.

[0114] The reaction mixture exiting this pipe is evaporated to separate the benzene and toluene solvents and the excess hydrogen bromide, and 11-bromoundecanoic acid with a purity close to 94% is isolated.

[0115] Example 2: Preparation of 11-aminoundecanoic acid by ammonolysis of 11-bromoundecanoic acid 32% ammonium hydroxide is placed in a jacketed reactor equipped with a mechanical stirrer at 0 °C. At atmospheric pressure, 220 g of molten 11-bromoundecanoic acid is added rapidly dropwise at 90 °C. The weight ratio of 32% ammonium hydroxide to 11-bromoundecanoic acid is 6 / 1. The temperature set point of the medium is adjusted to 22 °C, and then the reaction medium is subjected to a temperature increase from 2 °C to 32 °C up to the sixth hold, which also lasts for 12 hours and 30 minutes, every 12 hours and 30 minutes.

[0116] Example 3: Separation of 11-aminoundecanoic acid and treatment of the filtrate The reaction medium obtained in Example 2 is filtered, and the cake is washed with a small amount of water. Then, the cake is suspended in water such that the weight of the water used is 3.8 times the amount of 11-bromodecanoic acid used. The mixture is heated to 120 °C and then recrystallized by cooling to 25 °C. After filtration, the cake is washed with a small amount of water. The recovered solid is dried to obtain a powder of 11-aminoundecanoic acid.

[0117] All the filtrate is collected, then heated to 95 °C and evaporated under reduced pressure. Evaporation is stopped when a solid content of about 50% is reached, and then cooling to 25 °C is carried out. After solid-liquid separation, the cake of 11-aminoundecanoic acid is washed with water.

[0118] The filtrate from this crystallization step containing ammonium bromide and organic impurities in the aqueous solution is evaporated to a bromide concentration of about 350 g / l.

[0119] Next, 50 wt% sodium hydroxide in an aqueous solution is added in an appropriate amount to reach pH 11, and heating to 95 °C is carried out to generate ammonia, which is captured in water.

[0120] The recovered aqueous solution contains sodium bromide and organic impurities. The solution contains 3% of total organic carbon.

[0121] Example 4: Chlorination of Sodium Bromide In a column containing packing, the aqueous sodium bromide solution obtained in Example 3 above is continuously injected at the top of the column, chlorine is continuously injected into the lower quarter of the column, and steam is continuously injected at the bottom of the column, and the bottom of the column is heated to 100 °C. The flow rate of chlorine is adjusted to be 10% in excess moles relative to the bromide being injected.

[0122] A brine stream mainly composed of sodium chloride and water is recovered at the bottom of the column. The bromine recovered at the top of the column is condensed, then vaporized, and injected into a tubular reactor heated to 900 °C in co-current with hydrogen.

[0123] The formed hydrogen bromide is cooled and can be reused in the hydrobromination step described in Example 1.

[0124] The losses of bromine in the bromine synthesis column and the fouling of the hydrogen bromide synthesis reactor are listed in Table 1.

[0125] Example 5: Chlorination of Sodium Bromide with Organic Impurities Removed in Advance (Method A) The aqueous sodium bromide solution obtained in Example 3 above, cooled to 25 °C, is acidified with 33% hydrochloric acid to reach pH 4. The settled oily phase is separated. Then, the aqueous phase analyzed with 0.3% total organic carbon is treated as in Example 4.

[0126] The losses of bromine in the bromine synthesis column and the fouling of the hydrogen bromide synthesis reactor are listed in Table 1. [Table 1] JPEG0007712965000001.jpg39170

[0127] Example 6: Chlorination of Sodium Bromide with Prior Removal of Organic Impurities (Method C) The aqueous sodium bromide solution from Example 3 and Amberlite XAD 4 macroreticular resin are stirred at a weight ratio of 5:1 for 15 minutes, and then solid-liquid separation is performed. Next, the aqueous sodium bromide phase with a total organic carbon of 0.1% is treated as described in Example 4. The bromine loss in the bromine synthesis column and the fouling of the hydrogen bromide synthesis reactor are listed in Table 1.

[0128] Example 7: Chlorination of Sodium Bromide with Prior Removal of Organic Impurities (Method D) The aqueous sodium bromide solution from Example 3 is sent to an MPS-34 (Koch Membrane Systems) nanofiltration membrane at 50 °C and 30 bar. The volume concentration factor, defined as the ratio of the volume flow rate of the feed to the volume flow rate of the concentrate, is about 10. The measured average filtration flow rate is 6 kg / h / m 2 is. The total organic carbon measured for the permeate is 0.03%.

[0129] The amount of bromine lost in the concentrate (the ratio of the amount of bromide in the concentrate to the amount of bromide in the aqueous sodium bromide solution fed to the nanofiltration) is 5.4%.

[0130] The diafiltration step on the same membrane is performed on the concentrate after dilution with 0.5 volume of water per volume of concentrate. The second membrane separation step makes it possible to reduce the bromide loss to 1.4% of the bromide in the aqueous sodium bromide solution fed to the nanofiltration step.

[0131] Next, the collected permeate is treated as described in Example 4. The bromine loss in the bromine synthesis column and the fouling of the hydrogen bromide synthesis reactor are listed in Table 1.

[0132] Example 8: Chlorination of Sodium Bromide with Prior Removal of Organic Impurities (Method D) The aqueous sodium bromide solution from Example 3 is subjected to a Suez DK nanofiltration membrane at 50 °C and 30 bar. The measured average filtration flux is 24 kg / h / m 2 . The total organic carbon measured in the permeate is 0.2%. The amount of bromine lost in the concentrate without the diafiltration step is 0.3%.

[0133] The permeate is then treated as described in Example 4. The losses of bromine in the bromine synthesis column and the fouling of the hydrogen bromide synthesis reactor are listed in Table 1.

[0134] All the results show that the method according to the invention enables the recovery of a large amount of bromide in the effluents resulting from the method for producing 11-aminoundecanoic acid and 10-aminodecanoic acid, thus reducing the need to add bromine, which significantly improves the economics of the method while further reducing the amount of effluents.

[0135] [List of cited documents, etc.] U.S. Patent Application Publication No. 2009 / 0292073 A1 U.S. Patent Application Publication No. 2005 / 0004326 A1 U.S. Patent No. 8,013,251 B2 U.S. Patent Application Publication No. 2017 / 0242372 A1

Claims

1. A method for producing an aminocarboxylic acid of the following formula (I), NH2-CH ２ -(CH ２ ) ｎ -COOH (I) (wherein n is an integer from 7 to 12). The following steps: (i) An unsaturated carboxylic acid of the following formula (II) CH2=CH-(CH ２ ) ｎ－１ -COOH (II) is reacted with hydrogen bromide (HBr) to form an ω-bromoalkanoic acid of the following formula (III) Br-CH ２ -(CH ２ ) ｎ -COOH (III) ; a step of forming; (ii) reacting the obtained ω-bromoalkanoic acid of formula (III) with ammonia in an aqueous solution to form a reaction mixture containing the aminocarboxylic acid of formula (I) and ammonium bromide; (iii) separating the reaction mixture of the aqueous solution rich in the aminocarboxylic acid of formula (I) and ammonium bromide; (iv) contacting the obtained aqueous solution rich in ammonium bromide with sodium hydroxide to form ammonia and an aqueous solution rich in sodium bromide; (v) purifying the obtained aqueous solution rich in sodium bromide to remove organic impurities; (vi) contacting the obtained purified aqueous solution rich in sodium bromide with chlorine to form bromine and an aqueous solution rich in sodium chloride; (vii) reacting the obtained bromine with hydrogen to form hydrogen bromide, and (viii) recycling the obtained hydrogen bromide to step (i) A method comprising.

2. The method according to claim 1, wherein in formula (I), n is an integer from 8 to 10.

3. The method according to claim 1 or 2, wherein bromide derived from another method is added to the solution rich in ammonium bromide or sodium bromide in step (iv).

4. The method according to any one of claims 1 to 3, wherein bromine derived from another method is added to the bromine obtained in step (vi).

5. The method according to any one of claims 1 to 4, wherein the step (v) of purifying the aqueous solution of bromide enables the TOC to be reduced by 5 times to an extremely low level.

6. The method according to any one of claims 1 to 5, wherein step (vi) is carried out using a bromide solution having a TOC of less than 2%.

7. The method according to claim 6, wherein step (vi) is carried out using a bromide solution having a TOC of less than 1%.

8. The method according to claim 7, wherein step (vi) is carried out using a bromide solution having a TOC of less than 0.5%.

9. The method according to any one of claims 1 to 8, wherein step (v) is carried out by acidifying the aqueous solution rich in sodium bromide obtained as a result of step (iv), followed by decantation of the formed oily phase.

10. The method according to claim 9, wherein the aqueous solution rich in sodium bromide resulting from step (iv) is acidified to a pH between 3 and 5 by adding an acid.

11. The method according to any one of claims 1 to 10, wherein step (v) includes a subsequent step (va) of subjecting the oily phase formed in step (v) to an extraction operation to obtain an aqueous solution enriched in sodium bromide, which is returned to step (iv) or (vi).

12. The method according to any one of claims 1 to 8, wherein step (v) is carried out by neutralization of the aqueous solution rich in sodium bromide followed by liquid / liquid extraction.

13. The method according to claim 12, wherein the aqueous solution rich in sodium bromide is neutralized to a pH between 3 and 10 in step (v).

14. The method according to any one of claims 1 to 8, wherein step (v) is carried out by adsorption onto an adsorbent material.

15. The method according to any one of claims 1 to 8, wherein step (v) is carried out by membrane separation to form a permeate enriched in sodium bromide and depleted in organic impurities, and a concentrate depleted in sodium bromide and enriched in organic impurities.

16. The method according to claim 15, wherein step (v) is carried out by one or more nanofiltration membranes.

17. The method according to claim 15 or 16, wherein step (v) includes a subsequent step (va') in which the concentrate obtained in step (v), depleted in sodium bromide and enriched in organic impurities, is subjected to a diafiltration step to recover an aqueous solution enriched in sodium bromide and depleted in organic impurities, and this solution can be mixed with the permeate obtained from step (v).

18. The method according to any one of claims 15 to 17, wherein step (v) includes a subsequent step (vb) of subjecting the permeate obtained in step (v), enriched in sodium bromide and depleted in organic impurities, and, where appropriate, the aqueous solution enriched in sodium bromide and depleted in organic impurities resulting from step (va'), to a second step of membrane separation.

19. A method for producing a polyamide or copolyamide from an aminocarboxylic acid of formula (I) obtained by the method according to any one of claims 1 to 18.

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