EP0201925A1 - Verfahren zur Herstellung einer freien Aminosäure aus einem Alkalimetallsalz derselben - Google Patents

Verfahren zur Herstellung einer freien Aminosäure aus einem Alkalimetallsalz derselben Download PDF

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Publication number
EP0201925A1
EP0201925A1 EP86106619A EP86106619A EP0201925A1 EP 0201925 A1 EP0201925 A1 EP 0201925A1 EP 86106619 A EP86106619 A EP 86106619A EP 86106619 A EP86106619 A EP 86106619A EP 0201925 A1 EP0201925 A1 EP 0201925A1
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EP
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Prior art keywords
anolyte
alkali metal
amino acid
solution
metal salt
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EP86106619A
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English (en)
French (fr)
Inventor
Konosuke c/o Kabushiki Kaisha Musashino Kishida
Takatoshi c/o Kabushiki Kaisha Musashino Tanabe
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KK Musashino Kagaku Kenkyusho
Musashino Chemical Laboratory Ltd
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KK Musashino Kagaku Kenkyusho
Musashino Chemical Laboratory Ltd
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B3/00—Electrolytic production of organic compounds
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/14—Alkali metal compounds
    • C25B1/16—Hydroxides

Definitions

  • This invention relates to a process for electrolytically producing a neutral amino acid having one amino group and one carboxyl group and an alkali metal hydroxide from an alkali metal salt of said amino acid. More specifically, the present invention relates to a process for electrolytically producing a free neutral amino acid having one amino group and one carboxyl group and an alkali metal hydroxide from an alkali metal salt of said amino acid, with low electric power consumption and without causing the decompositional loss of said amino acid.
  • amino acids such as glycine, 0(-alanine, ⁇ -alanine, ⁇ -phenylalanine and the like can be produced by subjecting an alkali metal aminate (hereinafter abbreviated to an aminate) obtained from a reaction process or the like to ion exchange to convert the aminate to the corresponding amino acid.
  • an alkali metal aminate hereinafter abbreviated to an aminate
  • This ion exchange is conducted mainly by either of the following methods.
  • an electrolytic process for producing an alkali metal hydroxide from an inorganic salt such as sodium chloride or the like which comprises using an ion exchange membrane as a separating membrane.
  • an aqueous aminate solution is electrolyzed using the solution as an anolyte, in an electrolytic cell having a cation-exchange membrane for separating the anode chamber and the cathode chamber, the aminate will be converted to the corresponding amino acid and the corresponding alkali metal hydroxide with the amino acid being available in the anolyte and the alkali metal hydroxide being available in the catholyte.
  • this analogy is realized as anticipated, no acid is required; the alkali metal hydroxide is recovered; and there occurs no formation of a waste solution containing a large amount of a salt.
  • Electrolysis of an aqueous aminate solution using the solution as an anolyte causes decomposition of the amino acid. This not only results in the loss of the amino acid in an innegligible amount but also incurs in many cases coloring and generation of unusual odor in the anolyte. It is said that carboxylic acids also undergo anodic reactions and are decomposed; however, amino acids are decomposed more easily by electrolysis.
  • Fig. 1 is a diagram showing one example of the electrolytic apparatus used in the present invention process
  • Fig. 2 is a graph showing a relation between the pH of aqueous glycine solution used in electrolysis and the percentage of glycine lost due to electrolytic decomposition.
  • a cation-exchange membrane 3 is provided between an anode 1 and a cathode 2 to separate an anode chamber 4 and a cathode chamber 5.
  • an anolyte A namely, an aqueous solution containing an amino acid and an alkali metal salt thereof.
  • the anolyte may contain, besides said amino acid and said salt, an acid or acids stronger than said amino acid, such as organic acids (e. g . acetic acid) or mineral acids (e.g. sulfuric acid), or alkali metal salts thereof.
  • the anolyte must be formulated so as to have a pH of 9.5 or below. It is desirable that the anolyte be further formulated so that the ratio of the alkali metal ion concentration [M + to the hydrogen ion concentration [H +1, namely, [M + ]/[H + ] is at least 50.
  • a catholyte C namely, an alkali metal hydroxide solution.
  • This alkali metal hydroxide preferably is hydroxide of the same alkali metal as constitutes the aminate as a raw material.
  • the aminate in the anolyte is gradually converted to the corresponding amino acid; the alkali metal ion concentration [M ] in the anolyte decreases; and the pH of the anolyte comes down, in other words, the hydrogen ion concentration [H + ] increases. Therefore, in order to keep the pH and, desirably, also [M + ]/[H + ] at the respective ranges specified above, there is newly added to the anolyte an aqueous solution F containing the same aminate as in the anolyte (hereinafter the solution F is referred to as an original solution).
  • an anolyte amount exceeding that required for circulation is taken out as an ion-exchanged solution E. It is desirable that the operation of adding the original solution and the operation of taking out the ion-exchanged solution be conducted continuously. However, these operations may be conducted intermittently when the total volume of the anolyte circulation system is large or when the anolyte circulation system comprises a storage tank for the anolyte.
  • the cathode chamber water is consumed by the cathodic reaction and simultaneously an alkali metal hydroxide is formed. Therefore, water is added to the catholyte so that the alkali metal hydroxide concentration can be kept at a proper level. Since this increases the amount of the catholyte, a catholyte amount exceeding that required for circulation is taken out of the system as a recovered alkali R.
  • the recovered alkali R may be used in reaction processes, etc. as it is or after having been concentrated.
  • the concentration of alkali metal hydroxide at catholyte is decided in view of the performance characteristics of the ion-exchange membrane used, application of recovered alkali, etc. However, the concentration is desired to be at least 0.5 N to ensure a sufficient conductivity.
  • alkali metal salts of neutral amino acids show a pH of 11 or above in their aqueous solutions.
  • these aqueous solutions are subjected to electrolytic ion exchange, the pH of solution decreases as the proportion of free amino acid formed increases.
  • the amino acid tends to decompose as mentioned above, when contacted with the anode while the pH of the solution is still high. Even if the loss of the amino acid due to this decomposition is small, there occur other disadvantageous phenomena of (1) coloring of solution and (2) generation of unusual odor.
  • Fig. 2 shows a relation between the pH of solution and the decomposition loss of glycine per unit of current passed when various aqueous solutions containing glycine and sodium glycinate in various proportions have been subjected to electrolysis by passing between the two electrodes an electric current equivalent to the amount of glycine radical contained in the solution. It is appreciated from Fig.
  • the degree of amino acid decomposition varries with the kind of amino acid, the type of anode used, current density, co-existing substances, etc., the degree is affected predominantly by the pH of the solution to be electrolyzed. Therefore, a requirement of pH 9.5 or below holds universally. Since amino acids are more stable at lower pH, it is desirable that operation of electrolysis be carried out at a pH as low as possible as long as other conditions allow.
  • the present invention process enables electrolysis of alkali metal salts of almost all kinds of neutral amino acids. Exceptionally, the present invention can not be applied to amino acids having a thioether bond such as methionine, because these amino acids decompose even at low pH to incur an inneglibgible extent of loss.
  • the ion-exchanged solution taken out in the present invention process is part of the anolyte and accordingly has a pH of 9.5 or below which is same as that of the anolyte. Therefore, the most part of the amino acid contained in the ion-exchanged solution takes a form of free amino acid and only the small part takes a form of aminate.
  • the ratio of aminate to free amino acid is determined by the pH of ion-exchanged solution, namely, anolyte.
  • aqueous solutions containing sodium ⁇ -alanate and o(-alanine at proportions of 1:4, 1:9 and 1:99 have pH of 9.5, 9.07 and 8.04, respectively, at room temperature.
  • these pH values change slightly by the coexistence of other electrolytes.
  • Neutral amino acids show isoelectric points of about 6.
  • the most part of the amino acid contained in the ion-exchanged solution takes a form of free amino acid at a fairly wide pH range including the isoelectric point of the amino acid.
  • Separation of an amino acid from the ion-exchanged solution wherein the most part of the aminate supplied has been converted to the corresponding free amino acid can be done easily by concentration, crystallization, etc. In this separation operation, the aminate which has not been converted to the corresponding amino acid remains in a mother liquid; therefore, it can be added to the original solution for reuse in electrolysis.
  • electrolysis is conducted at a pH close to the isoelectric point of an amino acid to be obtained, to expect a very high conversion percentage from aminate to amino acid, because it makes operations such as crystallization and the like easier.
  • an aqueous amino acid solution has a very low conductivity while an aqueous aminate solution has a relatively high conductivity.
  • the supporting electrolyte there can be used, for example, acids stronger than the amino acid to be produced, such as acetic acid, iminodicarboxylic acid, phosphoric acid, sulfuric acid or the like, or alkali metal salts of said acids. It is desirable that the alkali metal contained in the supporting electrolyte be same as that constituting the raw material aminate.
  • the alkali metal hydroxide recovered becomes a mixture of two kinds of alkali metal hydroxides. If the situation allows the utilization of such a mixed alkali metal hydroxide, the supporting electrolyte may contain an alkali metal different from that in the raw material aminate.
  • an aqueous alkali metal aminate solution obtained by subjecting an amino nitrile produced from a reaction of aldehyde cyanhydrin with ammonia to hydrolysis with an alkali ordinarily contains, as a side product, a small amount of an alkali metal salt of a corresponding iminodicarboxylic acid.
  • This side product satisfies the above mentioned requirement for supporting electrolyte.
  • Such an impurity can function as a supporting electrolyte by remaining as it is. In many cases, it is not sufficient and addition of other supporting electrolyte is preferred. Desirable as the supporting electrolyte to be added are those which remain stable when contacted with an anode, such as sulfuric acid, phosphoric acid and their alkali metal salts.
  • an anolyte to be electrolyzed contains a supporting electrolyte and has a pH higher than the isoelectric point of the amino acid constituting the aminate contained in the anolyte
  • the aminate is predominantly subjected to ion exchange by electrolysis and is converted to the corresponding amino acid and the supporting electrolyte remains as it is, i.e., in the original salt form.
  • the anolyte containing a supporting electrolyte can have a pH lower than the isoelectric point of said amino acid.
  • [M + ]/[H + ] is desirably at least 50, more desirably at least 200.
  • [H + ] is 0.001 M and hence [M + ] is desirably 0.2 M or above.
  • a higher concentration of the supporting electrolyte reduces the required electrolytic voltage to a lower level until the concentration reaches a certain upper limit, although there is a fear that the higher concentration makes more difficult the separation of formed amino acid from ion-exchanged solution.
  • An amino acid of high purity can be separated even from an ion-exchanged solution containing such a large amount of supporting electrolytes, by means of repeated fractional crystallization or electrical dialysis for desalting followed by crystallization.
  • the most part of the supporting electrolyte can be recovered in the form of a solid or a solution, according to fractional crystallization or electrical dialysis and can then be reused.
  • an inexpensive salt is used as a supporting electrolyte, there is no need of recovering it.
  • An optimum concentration of the supporting electrolytes is determined in view of all the above mentioned matters and ordinarily it is 0.1 to 3.0 N.
  • both the anolyte and the catholyte be circulated in amounts as large as possible in order to prevent the increase of electrical resistance due to the shielding effect caused by bubbles of the gases generated at electrode surfaces.
  • the circulation amount desirably is at least 0.5 liter per 1 AH.
  • the apparent amount of circulation flowing through the external path of the circulation system can be reduced by constructing the cell so as to allow convection inside the electrode chamber as well as gas-liquid separation. In this case, too, the apparent circulation amount of anolyte must be determined so that the solution in the anode chamber can satisfy the aforementioned requirements for pH and [M + ]/[H + ].
  • the anode of the electrolytic apparatus used in the present invention process has a small overpotential during oxygen generation.
  • titanium having on the surface a catalyst layer composed mainly of iridium oxide is suitable as the anode.
  • Suitable as the cation-exchange membrane are perfluorocarbon type cation-exchange membranes such as commercially available Nafion (brand name).
  • Various metals can be used as the cathode. Of them, nickel- plated iron is least expensive and gives a good performance.
  • Integration of many of such unit cells into an apparatus capable of conducting electrolysis on a commercial basis can be done based on the technique already established in the field of sodium chloride electrolysis.
  • the present invention process can be operated also as a so-called SPE (solid polymer electrode) electrolytic process wherein a porous anode or a cathode or both of them are integrated with a cation-exchange membrane and an anolyte or a catholyte or both of them are circulated behind the electrode(s) to conduct electrolysis.
  • SPE solid polymer electrode
  • a 2M aqueous d-alanine solution was added to a 2M aqueous sodium d-alanate solution, whereby 5 kinds of aqueous solutions having the ratios of sodium ⁇ -alanate to d-alanine, of 1/0, 1/1, 1/5, 1/9 and 1/19 were prepared.
  • electrolytic ion exchange was conducted while circulating each of said solutions kept at 60°C and passing a direct current at 4V between the two electrodes, until the pH of the anolyte became about 7.0.
  • the ion-exchange membrane used was Nafion 315.
  • the pH of the anolyte before electrolysis, the recovery percentage of ⁇ -alanine in anolyte and the percentage of ⁇ alanine moved to catholyte both as measured by analyses of anolyte and catholyte after electrolysis, the total recovery percentage of d-alanine as a sum of the previous two percentages, and the properties of anolyte after electrolysis are shown in Table 1.
  • Table 1 As appreciated from the table, when a solution having a pH above 9.5 is electrolyzed as an anolyte, the loss of ⁇ -alanine due to decomposition, the coloring of anolyte and the generation of unusual odor in anolyte are striking.
  • the total amount of each of the anolyte and the catholyte was recovered and analyzed.
  • the cell voltage was 4.7 V; the current efficiency as obtained from the recovered amount of sodium hydroxide was 82%; and the recovery percentage of ⁇ -alanine was as follows.
  • Example 2 Using the same aqueous sodium ⁇ -alanate solution as used in Example 2, electrolytic ion exchange was conducted in the same manner as in Example 2 except that no supporting electrolyte was used.
  • the cell voltage was 9.8 V; the current efficiency was 80%; and the recovery percentage of ⁇ -alanine was as follows.
  • Example 2 Decompositional loss of d-alanine is seen neither in Example 2 nor in Example 3. However, the effect of sodium sulfate added as a supporting electrolyte is clearly seen when the cell voltages of Examples 1 and 2 are compared.
  • the cathion-exchange membrane used was Nafion 901.
  • the cell voltage was 4.4 V; the current efficiency was 95%; and the recovery percentage of glycine was as follows.
  • An ion-exchanged solution was obtained by repeating the same procedure as in Example 4 except that the pH of anolyte was kept at 10.5.
  • the cell voltage was 4.2 V; the current efficiency was 95%; and the recovery percentage of glycine was as follows.
  • the ion exchange percentage of ion-exchanged solution was 40% and the proportion of glycine lost to glycine formed by the ion exchange was 7.5%.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Inorganic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
EP86106619A 1985-05-15 1986-05-15 Verfahren zur Herstellung einer freien Aminosäure aus einem Alkalimetallsalz derselben Withdrawn EP0201925A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP60101567A JPS61261488A (ja) 1985-05-15 1985-05-15 アミノ酸アルカリ金属塩の電解法
JP101567/85 1985-05-15

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992007648A2 (en) * 1990-10-31 1992-05-14 Reilly Industries, Inc. Electro-synthesis of alcohols and carboxylic acids from corresponding metal salts
EP1016651A1 (de) * 1998-12-30 2000-07-05 Archer-Daniels-Midland Company Verfahren zu gleichzeitiger Herstellung von Aminosäurehydrochlorid und Alkali durch elektrodialytische Wasseraufspaltung
WO2002062826A1 (fr) * 2001-02-07 2002-08-15 Vadim Viktorovich Novikov Procede de fabrication des peptides
EP1659197A1 (de) * 2004-11-18 2006-05-24 Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO Verfahren zur zurückgewinnung von Säuren
US11271233B2 (en) 2013-09-25 2022-03-08 Lockheed Martin Energy, Llc Electrolyte balancing strategies for flow batteries
US11524931B2 (en) 2018-03-13 2022-12-13 Taminco Bv Process for drying N,N-dimethyl glycinate salte

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE652765C (de) * 1935-08-17 1937-11-09 Chem Fab Flora Verfahren zur Gewinnung von Aminosaeuren durch Elektrolyse
US2921005A (en) * 1952-10-17 1960-01-12 Rohm & Haas Electrolytic conversions with permselective membranes
DE3405522A1 (de) * 1984-02-16 1985-08-29 Basf Ag, 6700 Ludwigshafen Verfahren zur gewinnung von carbonsaeuren, die struktureinheiten der formel n-ch(pfeil abwaerts)2(pfeil abwaerts)-cooh enthalten, aus deren alkali- oder erdalkali-salzen

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE652765C (de) * 1935-08-17 1937-11-09 Chem Fab Flora Verfahren zur Gewinnung von Aminosaeuren durch Elektrolyse
US2921005A (en) * 1952-10-17 1960-01-12 Rohm & Haas Electrolytic conversions with permselective membranes
DE3405522A1 (de) * 1984-02-16 1985-08-29 Basf Ag, 6700 Ludwigshafen Verfahren zur gewinnung von carbonsaeuren, die struktureinheiten der formel n-ch(pfeil abwaerts)2(pfeil abwaerts)-cooh enthalten, aus deren alkali- oder erdalkali-salzen

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 96, no. 5, February 1, 1982, Columbus, Ohio, USA YUASA BATTERY CO., "Purification of amino acids" page 715, column 1, abstract no. 35722w & JPN. KOKAI TOKKYO KOHO JP 81 118 047, 16 SEPTEMBER 1981 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992007648A2 (en) * 1990-10-31 1992-05-14 Reilly Industries, Inc. Electro-synthesis of alcohols and carboxylic acids from corresponding metal salts
WO1992007648A3 (en) * 1990-10-31 1992-11-26 Reilly Ind Inc Electro-synthesis of alcohols and carboxylic acids from corresponding metal salts
EP1016651A1 (de) * 1998-12-30 2000-07-05 Archer-Daniels-Midland Company Verfahren zu gleichzeitiger Herstellung von Aminosäurehydrochlorid und Alkali durch elektrodialytische Wasseraufspaltung
WO2002062826A1 (fr) * 2001-02-07 2002-08-15 Vadim Viktorovich Novikov Procede de fabrication des peptides
EP1659197A1 (de) * 2004-11-18 2006-05-24 Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO Verfahren zur zurückgewinnung von Säuren
WO2006054893A2 (en) * 2004-11-18 2006-05-26 Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno Process for the recovery of acids
WO2006054893A3 (en) * 2004-11-18 2006-07-06 Schappelijk Onderzoek Tno Nl O Process for the recovery of acids
US11271233B2 (en) 2013-09-25 2022-03-08 Lockheed Martin Energy, Llc Electrolyte balancing strategies for flow batteries
US11843147B2 (en) 2013-09-25 2023-12-12 Lockheed Martin Energy, Llc Electrolyte balancing strategies for flow batteries
US11524931B2 (en) 2018-03-13 2022-12-13 Taminco Bv Process for drying N,N-dimethyl glycinate salte

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