JP2008101005A - Decomposition method for ammonium salt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel method that permits efficient manufacture at a low cost of a free organic acid having a high melting point from an ammonium salt of the organic acid obtained by microbial conversion of a carbon resource in the presence of a neutralizing agent while recycling and reusing reaction raw materials used or by-products without disposing of them. <P>SOLUTION: An ammonium salt of an organic acid A such as a dicarboxylic acid, a tricarboxylic acid or an amino acid is subjected to reaction crystallization, using an acid B such as a monocarboxylic acid satisfying equation (1) below to separate the free organic acid A as a solid. pKa(A)≤pKa(B) (1) (provided that pKa(A) and pKa(B) are the respective electrolytic dissociation constants of the organic acid A and the acid B and, when they have a plurality of electrolytic dissociation constants, represent the minimum pKa among them). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention, dicarboxylic acids, tricarboxylic acids, or organic acids having a high melting point such as amino acids (hereinafter referred to as "organic acid A" collectively.) For more information, biological ingredients glucose, dextrose, suitable when cellulose or the like to produce the organic acid a by microbial conversion, a new separation of organic acids, about the decomposition how suitable ammonium salt for the manufacture how organic acids including a purification step.

  Dicarboxylic acids such as succinic acid or derivatives thereof are widely used as raw materials for polymers such as polyesters and polyamides, particularly biodegradable polyesters, and as raw materials for foods, pharmaceuticals, and cosmetics. Tricarboxylic acids such as citric acid are widely used as food additives. In recent years, in particular, succinic acid is expected as a raw material for biodegradable polymers together with lactic acid.

  Succinic acid has conventionally been industrially obtained by hydrogenating maleic acid, which is a raw material derived from petroleum. Therefore, as a technique for producing organic acids such as malic acid, tartaric acid and citric acid from plant-derived raw materials, techniques using fermentation operations have been studied. In addition, amino acids have already been produced by a fermentation method, but the separation and purification of amino acids has conventionally been generally performed by isoelectric crystallization using sulfuric acid.

  Furthermore, these organic acids such as dicarboxylic acids and tricarboxylic acids have two or more carboxylic acids, or carboxylic acid groups and amino groups as functional groups, and generally have a melting point due to their hydrogen bonding. (Usually 120 ° C. or higher), and the distillation process, which is a general separation and purification technique, cannot be used in the production process. Further, in the production of these organic acids by fermentation, neutralization is necessary because microorganisms such as fungi and molds used for fermentation generally do not exhibit sufficient activity under low pH conditions. For this reason, the organic acid obtained from a fermenter is usually in the form of a salt with an alkali used for neutralization. This has caused the separation and purification of these organic acids to be more difficult.

  Conventionally, as a general method for separating and purifying an organic acid salt produced by fermentation, there is a method using electrodialysis (Japanese Patent Laid-Open No. 2-283289). However, since electrodialysis is increased in proportion to the production scale, there is a problem that even in industrial scale production, the merit of scale is small and the cost is high.

  A method using an ion exchange resin (USP 6,284,904) has also been proposed. In this method, a salt of strong acid and strong base (such as NaCl) is formed during the regeneration of the ion exchange resin, and eventually this salt needs to be discarded or treated by electrodialysis.

  In addition, a method of decomposing calcium succinate with sulfuric acid (Japanese Patent Laid-Open No. 3-038655) has also been proposed. This method has a problem in its treatment because a large amount of calcium sulfate is by-produced.

Further, as a promising method, a method of performing reactive crystallization by salt exchange reaction using sulfuric acid (Japanese Patent Publication No. 2001-514900, USP 5,958,744) has been proposed. That is, it is a method in which organic acid is precipitated and separated by adding sulfuric acid to organic acid ammonium salt and performing reaction crystallization.
In this method, the oxalic acid ammonium salt corresponding to the solubility remains in the crystallization mother liquor after separating the organic acid by crystallization, and the crystallization mother liquor also contains ammonium sulfate. In order to increase the recovery rate of the entire process, it is necessary to recover the organic acid ammonium salt remaining in the crystallization mother liquor. It is very difficult to separate the ammonium sulfate as a solid while remaining in it. In addition, even when trying to separate by gas-liquid separation operation such as distillation, the organic acid ammonium salt and ammonium sulfate have a very high melting point, and the organic acid ammonium salt undergoes a dehydration reaction under high temperature conditions to vaporize them, and organic The acid cannot be recovered. Further, this method requires special equipment for thermal decomposition of ammonium sulfate at 300 ° C. or higher in order to recover and reuse the sulfuric acid from ammonium sulfate.
JP-A-2-283289 USP 6,284,904 Japanese Patent Application Laid-Open No. 3-030685 Special table 2001-514900 gazette USP 5,958,744

The object of the present invention is to solve the above-mentioned conventional problems, in particular, to separate and purify free organic acid A from a salt of organic acid A produced by fermentation by microbial conversion of a carbon source in the presence of a neutralizing agent. Oite novel way of producing high organic acid a purity and, by the generated by-product salts to decompose and reused, low waste environmentally friendly, efficient organic acid a low cost Provided is a method for decomposing ammonium salts, which can be produced in a continuous manner.

As a result of intensive research on the above problems, the present inventor has found that the organic acid A targeted by the present invention is an acid such as a monocarboxylic acid that is a weak acid such as acetic acid or propionic acid (hereinafter referred to as “acid B”). In some cases, the solubility is generally small and the temperature dependency is large, and the ammonium salt of the organic acid A is focused on the acid B. If these characteristics are utilized, an ammonium salt of the organic acid A, which is difficult to decompose if judged only by pKa (Ka: acid dissociation constant, pKa = log ₁₀ Ka) by reaction crystallization using acid B, is used as an acid. It was found that the ammonium salt of the acid B produced as a by-product can be decomposed under relatively mild heating conditions, and the ammonia obtained by the decomposition can be reused.

  In the present invention, “ammonium salt” means a monoammonium salt, a diammonium salt, and / or a triammonium salt unless otherwise specified.

  In general, it is a well-known fact that a weak acid salt is decomposed by a strong acid by a salt exchange reaction, and a weak acid can be obtained as a by-product of the strong acid salt. In this method, a salt exchange reaction is performed (USP 5,958,744). Moreover, the method using an ion exchange resin also requires that the acid strength of the ion exchange resin is stronger than that of dicarboxylic acid or tricarboxylic acid. However, as described above, such a method produces a salt of a stronger acid than the corresponding organic acid.

When comparing pKa which is an index of acid strength of acid-base exchange reaction, for example, pKa of oxalic acid and acetic acid is as follows, and the first ammonia (second pKa of ammonium oxalate salt (diammonium salt) is as follows: ) Is capable of an acid-base exchange reaction with acetic acid, but it can be seen that the second ammonia (monoammonium salt) is difficult to undergo an acid-base exchange reaction with acetic acid.

Therefore, as described above, conventionally, a method using a strong acid or a strongly acidic ion exchange resin has been adopted. As shown in JP-T-2001-514900, in crystallization using an inorganic acid, since the ammonium salt of the inorganic acid is generally non-volatile, a high recovery rate is required in one-stage crystallization. Therefore, in the case of oxalic acid, since the first pKa is 4.21, the pH must be smaller than 2.1 in order to obtain a sufficient recovery rate. Thus, in Japanese translations of PCT publication No. 2001-514900, reaction crystallization is performed using sulfuric acid. This method particularly requires a pH of 1.5 to 1.8.

  However, the present inventor uses an acid B such as a monocarboxylic acid that is weaker than the target organic acid A and easily crystallizes the organic acid A, which is difficult to obtain only by an acid-base reaction. It was found that it can be separated and purified.

  That is, the present inventor has shown that the organic acid A obtained as a result of microbial conversion in the presence of a neutralizing agent is highly soluble as an ammonium salt of the organic acid A with respect to the acid B, which is a weak acid, and is an ammonia-free organic acid. Focusing on the low solubility of A, the present inventors have found that there is a region that dissolves in acid B as an ammonium salt of organic acid A but cannot be dissolved as ammonia-free organic acid A.

  On the other hand, since the acid B functions as a proton source, the pH is lowered by coexistence of a sufficient amount of the acid B, and the acid-base reaction with the acid B causes the ammonia-free organic acid A to be converted from the ammonium salt form. I can do it. When the ammonia-free organic acid A is present above its solubility, the ammonia-free organic acid A is deposited. At this time, the organic acid A in the form of an ammonium salt has a sufficiently high solubility in the acid B and does not precipitate at the same time.

  From these newly discovered findings, the present inventor used acid B, which is a weaker acid than organic acid A, and obtained organic acid A, which was difficult to obtain only by acid-base reaction, by reaction crystallization. Succeeded in being separable.

  On the other hand, in this case, the recovery rate per stage may be worse than the conventional crystallization using a strong acid. Therefore, it is preferable for industrial implementation to separate and recover the by-product acid B ammonium salt and organic acid A ammonium salt contained in the mother liquor and recycle them from the mother liquor. Further, when the salt of the acid B produced as a by-product is discarded, a waste problem occurs as in the prior art. Therefore, it is preferable to decompose and reuse the ammonium salt of the acid B produced as a by-product. .

  The inventor of the present invention is that the ammonia constituting the ammonium salt of the organic acid A is a volatile base, and the acid B is a volatile acid, preferably a saturated monocarboxylic acid having a low boiling point such as acetic acid or propionic acid. It has been found that when used, the ammonium salt of acid B can be vaporized. By this operation, the organic acid A was successfully recovered from the mother liquor obtained by reaction crystallization.

Thus, the present invention is characterized by having the following gist .

1 . In the method of decomposing acid B ammonium salt into acid B and ammonia to separate and recover acid B and ammonia, acid B ammonium salt and acid B alkali metal salt and / or alkaline earth metal salt and water A step of heating the liquid containing the aqueous solution to extract the gas of the basic aqueous solution, and the direct or condensation of the basic aqueous solution extracted in the heating step, followed by gas-liquid separation at a temperature below the melting point of the ammonium salt of the acid B A method for decomposing an ammonium salt, comprising gas-solid separation or gas-liquid solid separation.

2 . In the method of decomposing acid B ammonium salt into acid B and ammonia to separate and recover acid B and ammonia, acid B ammonium salt and acid B alkali metal salt and / or alkaline earth metal salt and water And a heating step of extracting the gas of the basic aqueous solution from the top of the distillation column. A method for decomposing ammonium salts characterized by the above.

3 . The alkali metal and / or alkaline earth metal constituting the alkali metal salt and / or alkaline earth metal salt of acid B is one or more selected from the group consisting of Na, K, Ca, and Mg. 3. A method for decomposing an ammonium salt as described in 1 or 2 above.

4 . 4. The method for decomposing an ammonium salt according to any one of 1 to 3 above, wherein the acid B is one or more selected from the group consisting of formic acid, acetic acid, propionic acid, and butyric acid.

5 . 1 to 4 comprising the step of separating and recovering acid B by separating and recovering acid B by a separation step at 125 ° C. or higher under reduced pressure or normal pressure after extracting the gas of the basic aqueous solution in the heating step. The method for decomposing an ammonium salt according to any one of the above.

6 . 6. The method for decomposing an ammonium salt as described in 5 above, wherein the residual liquid after the separation and recovery step is mixed with a system containing water, and the amide compound by-produced in the heating step and the separation and recovery step is hydrolyzed and then circulated to the heating step .

Na us, pKa of a compound such as various organic acid, the other characteristics are shown in Table 2 below.

According to the present invention, a free organic acid A is converted from an ammonium salt of an organic acid A having a high melting point such as dicarboxylic acid, tricarboxylic acid, and amino acid produced by microbial conversion of a biological carbon source into a conventional acid-base reaction. in unexpectedly, the reactive crystallization utilizing an acid base reaction using a weak acid B such as a monocarboxylic acid, a weak acid than the organic acid a, isolated as a solid, organic acid a by reaction応晶analysis From the crystallization mother liquor after precipitation and separation, an acid B such as a monocarboxylic acid and an ammonium salt of an acid B such as an ammonium salt of a monocarboxylic acid are vaporized and efficiently separated to obtain an organic acid A and its ammonium salt. It can be recovered. The side reaction in this vaporization operation can be prevented, and the separation and recovery efficiency of each substance can be increased. The separated acid B, organic acid A and ammonium salt thereof can be circulated and reused without requiring complicated operations.

  Further, a method is provided in which the separated ammonium salt of acid B such as monocarboxylic acid ammonium salt is decomposed into acid B such as monocarboxylic acid and ammonia using an alkali (earth) metal salt. At that time, the water B present in the reaction system and the acid B such as monocarboxylic acid can be easily separated to efficiently recover the acid B having a low water content and the ammonia water not containing the acid B.

  Embodiments of an organic acid production method to which the present invention is applied will be described in detail below.

[Formation of ammonium of organic acid A]
Examples of the organic acid A produced in the present invention include those having a melting point of preferably 120 ° C. or higher. The carbon number is preferably 4 to 12, and a linear dicarboxylic acid, a tricarboxylic acid or the like is a typical example. The organic acid A preferably has two or three carboxyl groups bonded to a saturated or unsaturated aliphatic carbon, may have a branched or cyclic structure, and has a substituent. You may do it. The organic acid A also includes amino acids having a melting point of preferably 120 ° C. or higher.

  Specifically, the organic acid A is, for example, succinic acid, fumaric acid, maleic acid, malic acid, tartaric acid, aspartic acid, glutaric acid, glutamic acid, adipic acid, suberic acid, citric acid, itaconic acid, terephthalic acid, Examples include phenylalanine, tryptophan, asparagine, glutamine, valine, isoleucine, leucine, histidine, methionine, tyrosine and the like. Two or more of these may be mixed. Of these, preferred organic acids A include succinic acid, adipic acid, glutamic acid, suberic acid, tartaric acid, citric acid and the like. Particularly preferred are succinic acid, adipic acid, glutamic acid, and suberic acid.

  These organic acids A are produced, for example, by microbial conversion using a carbon source as a starting material. As the carbon source, carbohydrates such as galactose, lactose, glucose, fructose, glycerol, sucrose, saccharose, starch, and cellulose; and fermentable carbohydrates such as polyalcohols such as glycerin, mannitol, xylitol, and ribitol are usually used. Of these, glucose, fructose, and glycerol are preferable, and glucose is particularly preferable. As a broader plant-derived material, cellulose, which is the main component of paper, is preferable. Moreover, the starch saccharified liquid, molasses, etc. containing the said fermentable saccharide | sugar are also used. These fermentable carbohydrates may be used alone or in combination of two or more.

  The microorganism used for microbial conversion is not particularly limited as long as it has the ability to produce organic acid A. For example, anaerobic bacteria such as Anaerobiospirillum genus (USP 5,143,833), Actinobacillus genus (USP 5,504,004), A facultative anaerobic bacterium such as Escherichia (USP 5,770,435) or an aerobic bacterium such as Corynebacterium (Japanese Patent Laid-Open No. 11-113588) can be used. Reaction conditions such as reaction temperature and pressure in microbial conversion will depend on the activity of the selected fungus body, mold, etc., but suitable conditions for obtaining the corresponding organic acid A depend on each case. Just choose.

  In the above microbial conversion, a neutralizing agent is used because the metabolic activity of the microorganism is lowered or the activity of the microorganism is stopped when the pH is lowered, and the production yield is deteriorated or the microorganism is killed. Usually, the pH in the reaction system is measured by a pH sensor, and the pH is adjusted every time the neutralizing agent is added so that the pH is within a predetermined range. In the present invention, the addition method of the neutralizing agent is not particularly limited, and may be continuous addition or intermittent addition.

Examples of the neutralizing agent include ammonia, ammonium carbonate, urea, alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal carbonate, alkaline earth metal carbonate (in the following, An alkali metal and / or an alkaline earth metal may be referred to as an “alkali (earth) metal”). Ammonia, ammonium carbonate and urea are preferred. That is, as described above, when an alkali (earth) metal hydroxide or an alkali (earth) metal carbonate is used, in the reaction crystallization with acid B, the alkali (earth) metal of acid B is used. Since a salt is by-produced and the alkali (earth) metal used for neutralization cannot be directly recovered, a step of obtaining an ammonium salt of acid A is required in the Solvay method reaction step. Examples of the alkali (earth) metal hydroxide include NaOH, KOH, Ca (OH) ₂ , Mg (OH) ₂ , or a mixture thereof. Examples of the alkali (earth) metal carbonate include _{is, Na 2 CO 3, K 2} CO 3, CaCO 3, MgCO 3, NaKCO 3 etc., or the like and mixtures thereof.

  The pH value adjusted with these neutralizing agents is adjusted to a range in which the activity is most effectively exhibited depending on the type of fungus body, mold, etc., but in general, pH is 4 to 10, preferably It is in the range of about 6-9.

  The ammonium salt of organic acid A, which is the raw material of organic acid A produced in the present invention, is not necessarily limited to that obtained by the above-described microbial conversion, and is produced from a petrochemical process or other various processes, or by-product. Applicable to what is done.

[Reaction crystallization]
In general, crystallization refers to an operation for precipitating a necessary component in a state where unnecessary components are dissolved in a solvent. In the present invention, “reaction crystallization” refers to obtaining a necessary component by reaction and simultaneously performing crystallization. Say operation. That is, it means an operation of simultaneously crystallizing the object while performing a reaction for obtaining the object to be crystallized. In the present invention, the organic acid A is separated and purified by reaction crystallization using the acid B which is weaker than the organic acid A as described above. The acid B to be used must satisfy the following formula (1).
pKa (A) ≦ pKa (B) (1)
(However, pKa (A) and pKa (B) represent the ionization index of organic acid A and acid B, respectively, and when they have a plurality of values, represent the smallest pKa of them.)

  In addition, although greatly influenced also by the functional group which the organic acid A has, it is preferable that pKa (B) is 0-3 larger than pKa (A), even if the said Formula (1) is satisfied.

  Examples of the acid B include preferably monocarboxylic acids having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms, and specifically selected from formic acid, acetic acid, propionic acid, normal butyric acid, and isobutyric acid. 1 type or 2 types or more are mentioned. Of these, acetic acid or propionic acid is preferred from the viewpoint of low corrosiveness to the apparatus material and latent heat of vaporization. More preferably, it is an acid by-produced by the microbial cells used for microbial conversion. For example, in the case of the microbial cells described in JP-A-11-206385 and Japanese Patent Application No. 2002-34826, acetic acid is preferable. Also, acid B must be volatile in order to separate from the alkali metal salt. Furthermore, it is preferable that it is stable against heat. What is not preferable is specifically one having a carbon-carbon double bond or triple bond, and polymerizing or decomposing under conditions of 200 ° C. or less in the presence of an alkali (earth) metal, or as a functional group Peroxides and peroxides that self-decompose at 200 ° C or less in the presence of alkali metals, or have multiple functional groups in one molecule such as lactic acid, tartaric acid, and amino acids However, they are those that make a polymer (polyester or polyamide) alone.

  As described above, the organic acid A is obtained from the fermenter as a dilute aqueous solution in the form of a salt with a neutralizing agent used in microbial conversion. Therefore, the organic acid A as a product can be produced by separating and purifying the organic acid A from the reaction solution discharged from the fermenter. Here, the case where one or more selected from the group consisting of ammonia, ammonium carbonate, and urea (hereinafter may be referred to as “ammonia-based neutralizer”) is used as the neutralizer. To do.

  In this case, the reaction liquid from the fermenter containing the ammonium salt of organic acid A is generally a dilute aqueous solution, and it is preferable to concentrate this reaction liquid. The concentration method is not particularly limited, and examples thereof include evaporation, crystallization using alcohol, membrane separation using reverse osmotic pressure, electrodialysis using an ion exchange membrane, and the like. Among them, as described above, electrodialysis has the disadvantages that scale merit cannot be obtained and the apparatus cost and operation cost are high. In crystallization using alcohol or the like, an extra distillation device is required to recover the alcohol. From this point of view and cost, distillation is preferable, and distillation using a multi-effect can is preferable.

  As the degree of concentration of the reaction solution, even if it is a high concentration aqueous solution, for example, a high concentration aqueous solution of 40% by weight or more of the organic acid A ammonium salt, it is concentrated until the organic acid A ammonium salt is precipitated as a solid. May be. In the case of a high-concentration aqueous solution, there is an advantage that it can be easily dissolved in the acid B and can be easily operated as compared with a slurry or a solid. On the other hand, when the ammonium salt of the organic acid A is made into a solid form, mixing of water and the acid B can be avoided, and even if excessive ammonia or an ammonium salt of the acid B produced as a by-product exists, for example, a thin film If an evaporator is used, there is an advantage that it can be removed by vaporization in the drying / evaporation process. Which degree of concentration is used is appropriately determined so that the entire process can be optimized, including the reaction conditions for microbial conversion that affects the type and amount of impurities.

  Depending on the type of organic acid A and the type of acid B, the number of stages of reaction crystallization may be one stage or multiple stages (multiple stages). Due to restrictions on initial investment, operating conditions, and recovery rate, there are usually multiple stages, and 2 to 4 stages are often preferred. Moreover, when performing multistage crystallization, the thing whose pH is 7 or less corresponds to the reaction crystallization in this invention. If the pH is 7 or less, for example, if the organic acid A is oxalic acid, a monoammonium salt of oxalic acid can be obtained from the diammonium salt of oxalic acid. It can be obtained with a high recovery rate. Therefore, it corresponds to reaction crystallization.

  In the final stage of reaction crystallization (when reaction crystallization is a single stage, in the first stage), the amount of acid B added to the reaction solution is the amount by which organic acid A is precipitated by addition of acid B, ie, acid It is sufficient that the amount of the organic acid A is sufficient to be produced by the acid-base reaction between B and the ammonium salt of the organic acid A, and the amount of the produced organic acid A is not dissolved but is precipitated. The amount of acid B added varies depending on the type of acid B and pKa, the type and pKa of organic acid A, the degree of concentration of the fermentation reaction solution, and the like, and is not particularly limited. In terms of workability, precipitation efficiency, etc., the amount of acid B added is about 1 to 100 moles, preferably 1.5 to 30 moles, relative to the ammonium salt of organic acid A when the concentrate is solid. About twice, more preferably about 2 to 20 mole times.

  In addition, the system in which the organic acid A is precipitated may contain water. In particular, under conditions where a large amount of ammonia is present, in order to dissolve the ammonium salt of acid B produced as a by-product, it is often preferable that water is contained, and water is added even when the amount of acid B used is small. May be.

  There are no particular restrictions on the conditions for reaction crystallization of the organic acid A by addition of the acid B. In general, the acid B is added to the concentrate of the reaction solution and heated, and then cooled and allowed to stand. Good. Alternatively, water may be added to dissolve the ammonium salt of organic acid A, and then acid B may be added to cause crystallization. The latter method is effective for an organic acid A such as glutamic acid, which has a low solubility in water in an acid state and a high solubility when converted to a salt, and the difference between the two is remarkable.

  The heating temperature, heating time, and cooling temperature during crystallization vary depending on the type of organic acid A in the concentrate, the type of acid B used, the amount added, and the like, but are generally 60 to 130 ° C. After complete dissolution, the temperature is 50 ° C. or lower, preferably 40 ° C. or lower, and it is preferably cooled and left at 0 ° C. or higher, preferably 10 ° C. or higher.

  When acetic acid is used as the acid B, the melting point is 16 ° C., but it is possible to lower the cooling temperature to near 10 ° C. due to the freezing point depression. Considering a practical process, 15 ° C. or higher is preferable as a safe condition for preventing acid B from solidifying. In particular, in the case of a continuous process, it is preferable that the temperature of the utility (refrigerant) of the heat exchanger has a temperature difference of about 10 ° C. with respect to the target temperature. C. or higher is a more preferable condition.

  The reaction crystallization in the present invention can be carried out in accordance with a conventional method using a commonly used crystallization apparatus. However, in some organic acids A, particularly oxalic acid, the crystallization rate is low, so It is preferable to adopt a device for improving the amount of crystallization, such as circulating or taking a long residence time.

  By performing reaction crystallization, an organic acid A having a low solubility with respect to the acid B is produced by an acid-base reaction between the ammonium salt of the organic acid A obtained by microbial conversion using an ammonia-based neutralizing agent and the acid B. To precipitate. Therefore, the organic acid A having a high purity as the target product can be recovered by separating the precipitate from the crystallization solution by filtration or the like. The obtained organic acid A is made into a product after purification by recrystallization using acid B or the like, if necessary.

  In the production of organic acid A by microbial conversion, the production efficiency may vary depending on the microorganism, depending on the microorganism. Therefore, as the neutralizing agent, an alkali metal and / or alkaline earth metal hydroxide or carbonate (hereinafter referred to as an “alkali (earth) metal-based neutralizing agent” rather than the ammonia-based neutralizing agent). May be preferred). When an alkali (earth) metal-based neutralizing agent is used, the organic acid A by microbial conversion is produced in the form of an alkali (earth) metal salt, but the alkali (earth) metal does not volatilize. It is difficult to separate the alkali (earth) metal salt of the organic acid A and the acid B from the mother liquor composed of the alkali (earth) metal salt of the acid B and the organic acid A that are by-produced by the reaction crystallization. .

  For this reason, when using an alkali (earth) metal-based neutralizing agent, an organic acid A ammonium salt is obtained by exchanging the base using the Solvay method as the first reaction crystallization step. The organic acid A can be obtained by reaction crystallization of the ammonium salt of the acid A with the acid B in the second reaction crystallization step. Even in this case, it is preferable that the reaction solution obtained in the microorganism conversion step is concentrated and then subjected to the first reaction crystallization step.

  In the first reaction crystallization step, first, ammonia and carbon dioxide and / or ammonium carbonate are added to the concentrate obtained in the concentration step, and the aqueous solution of the alkali (earth) metal salt of the organic acid A is used. Alkali (earth) metal carbonate is deposited. In this first reaction crystallization step, the amount of ammonia and carbon dioxide and / or ammonium carbonate added is not particularly limited as long as it is sufficient for precipitation of alkali (earth) metal carbonate.

  In the first reaction crystallization step, an alkali (earth) metal carbonate is precipitated from an alkali (earth) metal salt of the organic acid A, and an ammonium salt of the organic acid A is generated. From the ammonium salt of the organic acid A produced in the first reaction crystallization step, then in the second reaction crystallization step, in the same manner as in the reaction crystallization step in the case of using the above-mentioned ammonia-based neutralizing agent, the acid B Organic acid A can be precipitated by reaction crystallization.

  Separation, recovery and recycling of acid B, organic acid A and its ammonium salt in the separation mother liquor After separation of organic acid A from the recrystallization reaction crystallization liquid (hereinafter sometimes referred to as “crystallization mother liquor” or “mother liquor”) ) Includes an ammonium salt of an organic acid A, an ammonium salt of an acid B generated by an acid-base reaction with the organic acid A, an excess acid B, and a remaining organic acid A. In the present invention, the acid B and its ammonium salt can be efficiently separated from these separated mother liquors by the following method, and the organic acid A ammonium salt and the organic acid A can be recovered. The separated ammonium salt of acid B is decomposed, and the resulting acid B and ammonia are reused.

  In the present invention, first, the acid B is vaporized and removed from the crystallization mother liquor, and then heated to vaporize the ammonium salt of the acid B. The vaporization of acid B from the crystallization mother liquor is preferably carried out below the melting point of the ammonium salt of acid B. For example, a kettle evaporator, a thin film evaporator, or a flash drum or heat exchanger having a heating unit And a flash drum, or a combination of these. In the case of using a distillation column type, the crystallization mother liquor may be supplied to, for example, the condenser part, the reflux line, or any other location as long as the inside of the column is not higher than the melting point of the ammonium salt of acid B. In addition, the specification and form of the apparatus are not limited as long as the acid B can be vaporized at a temperature equal to or lower than the melting point of the ammonium salt of the acid B.

The temperature range for vaporizing the acid B is preferably 20 ° C. or higher and the melting point of the ammonium salt of the acid B or lower. As the ammonium salt of acid B in the present invention, for example, typical ammonium acetate has a melting point of 114 ° C. The melting point has a specific meaning in the movement of molecules, and when ammonium acetate exceeds the melting point, it is vaporized while thermally decomposing. The boiling point of the ammonium salt of the acid B always theoretically exists, and there is also a phenomenon such as sublimation, and it is considered that the contribution of evaporation and sublimation cannot be strictly separated from that due to thermal decomposition. Therefore, vaporization of the ammonium salt of acid B may be referred to as “decomposition / vaporization” in the present invention. On the other hand, ammonium propionate is highly deliquescent and the melting point is not known. However, considering the similarity to ammonium acetate, it is unlikely that the difference in melting point between acetic acid and propionic acid is simply the difference in melting point between its ammonium salts, but a temperature slightly lower than 114 ° C., about 100 ° C. is propion. It is assumed to be the melting point of ammonium acid.

  Thus, although the vaporization temperature of the acid B varies depending on the type of the acid B (that is, the type of the ammonium salt of the acid B), generally a range of 40 to 100 ° C. is preferable.

  There are no particular restrictions on the operating conditions other than the temperature at which the acid B is vaporized at such a temperature, but the pressure conditions may be reduced to normal pressure or pressure because the corrosion of the equipment material becomes severe when pressurized. preferable. Particularly preferred is a reduced pressure condition of 10 to 400 mmHg, more preferably 40 to 200 mmHg.

  When the acid B is vaporized, a substance having a melting point lower than that of the acid B contained in the crystallization mother liquor, such as water, is also vaporized.

  In this way, the acid B in the crystallization mother liquor is vaporized and recovered, but the subsequent operations such as vaporization of the ammonium salt of the acid B, recovery of the remaining ammonium salt of the organic acid A and the organic acid A, etc. From the viewpoint, the amount of acid B to be removed by evaporation from the crystallization mother liquor varies depending on the amount of acid B and other components in the crystallization mother liquor, but the degree of vaporization may be until the mother liquor becomes a slurry. . Vaporizing until it becomes solid is not preferable because the thermal conductivity of the second vaporizer deteriorates in a conventional manner (for example: thin film evaporator). As a standard, the organic acid A is saturated with respect to the vaporization temperature. The saturation solubility is determined by the amount of acid B ammonium salt corresponding to the amount of ammonia to be removed and the amount of organic acid A dissolved at the crystallization temperature. In the following, the crystallization mother liquor after vaporizing the acid B may be referred to as “first residual liquid”.

  In vaporizing the ammonium salt of acid B after vaporizing acid B, the residence time is important. That is, as is clear from the results of the experimental examples described later, the amidation reaction is rapidly accelerated by heating at around 120 ° C. On the other hand, in order to separate the ammonium salt of the acid B from the organic acid A and its ammonium salt, it is necessary that the temperature is higher, and the melting point of the ammonium salt of the acid B is particularly preferable.

  Therefore, in order to prevent side reactions such as amidation under such high temperature conditions, the method for vaporizing the ammonium salt of acid B preferably has a short heating time. Further, it is preferable to vaporize in an overheated state, that is, to heat the process fluid under a reduced pressure condition and a sufficiently high-temperature heat source. As the heat source, steam and heating oil are generally considered. In that case, it is considered that the heating temperature is preferably 200 ° C. or lower in consideration of the corrosivity due to the acid B. In addition, for example, the temperature may be rapidly increased by applying molecular vibration by electromagnetic waves. However, the heating temperature only needs to be higher than the melting point, and there is no particular upper limit if the residence time is sufficiently short.

  Therefore, the operable range of the process fluid is 0.001 mmHg (0.133 Pa) or more and 200 mmHg (26.7 kPa) or less, more preferably 100 mmHg (13.3 kPa) or less. More preferably, it is 20 mmHg (2.67 kPa) to 90 mmHg (12.0 kPa).

  As an apparatus meeting such conditions, a thin film evaporator suitable for heating in a short time under reduced pressure is generally mentioned. In addition, for example, a heater with spraying, an evaporator having a temperature difference between the utility and the process fluid of 20 ° C. or more can be used. The heating method is not particularly limited, and may be a method in which molecular vibration is applied by electromagnetic waves and the temperature is rapidly raised on the same principle as a microwave oven. In addition, any operation that satisfies the depressurization condition and the high temperature condition is acceptable, and the apparatus, the principle, and the structure thereof are not limited as long as the heating time is short and a sufficient amount of heat can be given.

  The heating temperature varies depending on the type of ammonium salt of acid B and the pressure conditions, but in the case of ammonium acetate, it is preferably 115 to 180 ° C, more preferably 120 to 160 ° C, and in the case of ammonium propionate, 100 It is preferable that it is -180 degreeC.

  Thus, the liquid or slurry obtained by vaporizing the ammonium salt of acid B from the first residual liquid (hereinafter sometimes referred to as “second residual liquid”) remains with the organic acid A and its ammonium salt. The acid B and its ammonium salt are contained, and the organic acid A can be further recovered by processing by circulating to the reaction crystallization step.

  In the present invention, the acid B vaporized and separated from the crystallization mother liquor after the organic acid A is precipitated and separated by the reaction crystallization of the ammonium salt of the organic acid A and the acid B is recycled to the reaction crystallization step for reuse. It is preferable to do. The acid B may contain water and other substances in addition to the acid B. The recovered acid B is usually purified and then reused as a crystallization solvent. However, depending on the type and amount of impurities, it can be used as it is without purification.

[Decomposition of ammonium salt of acid B]
The ammonium salt of acid B vaporized and separated from the crystallization mother liquor is decomposed into acid B and ammonia. Although the method for decomposing the ammonium salt of acid B is described below, it is not limited to the ammonium salt of acid B obtained from the separation mother liquor of organic acid A, but also to the ammonium salt of acid B obtained from other processes. The same applies.

  In the method for decomposing an ammonium salt of acid B in the present invention, in the heating step, a liquid containing an ammonium salt of acid B, an alkali (earth) metal, and water, preferably, an ammonium salt of acid B and water A liquid obtained by adding an alkali (earth) metal salt of acid B to the mixed liquid (hereinafter sometimes referred to as “raw material liquid”) is heated to extract the gas of the basic aqueous solution. Hereinafter, this heating step is sometimes referred to as “heating step”, and the operation at that time is sometimes referred to as “heating operation”.

  When the temperature of the gas of the basic aqueous solution extracted in the heating step is higher than the melting point of the ammonium salt of acid B, part of acid B is also extracted. Therefore, after the extracted basic aqueous solution gas is directly or condensed, the ammonium salt of acid B is gas-liquid separated, gas-solid separated or vaporized at a temperature below the melting point of the ammonium salt of acid B under reduced pressure or normal pressure. Liquid-solid separation. Hereinafter, this separation step may be referred to as a “separation step” and the operation thereof may be referred to as a “separation operation”.

  The alkali metal and / or alkaline earth metal that forms the alkali metal salt and / or alkaline earth metal salt of the acid B is one or more selected from the group consisting of Na, K, Ca, and Mg. Two or more types are preferred. Particularly preferred is Na or K.

  The apparatus used in this heating step may be any apparatus as long as the heating operation can be performed and the gas phase and the liquid phase can be separated. The heating and gas-liquid separation may be separate devices, or a combination of a heat exchanger and a flash drum. If it is a kettle type heat exchanger, heating and gas-liquid separation can be performed with one apparatus. The heating mechanism is not particularly limited, and may be a flash drum including a jacket and a heat transfer coil, for example.

  A distillation column is most desirable for efficient gas-liquid separation with heating. The distillation column may be either a packed column or a plate column, and there are no particular restrictions on the structure, but a plate column is desirable for securing the residence time as described later. The reboiler may be a built-in type or an external type. In the case of using an external reboiler, a forced circulation reboiler, a thermosiphon reboiler, a kettle reboiler, and the like are conceivable, but are not limited thereto. In the present invention, an operation performed by combining a distillation column and a reboiler is regarded as a heating operation.

  There is no restriction on the presence or absence of a condenser, and the condenser does not form part of the heating operation. Theoretically, a kettle heat exchanger and a flash drum with a heating device can also be regarded as a one-stage distillation column.

  Since the gas extracted in the heating process contains ammonia and inevitably has a pH higher than 7, in the present invention, this is referred to as a heating process for extracting the gas of the basic aqueous solution.

  Among the apparatuses for performing the heating operation for extracting the gas of the basic aqueous solution, the most desirable one is a distillation column. Therefore, the case where a distillation column is mainly used will be described below.

  A distillation column is suitable for obtaining the separation effect of acid B and water by the salt effect and simultaneously decomposing the ammonium salt of acid B. Ammonia is not in the normal vapor-liquid equilibrium (evaporation and condensation are the same amount), but is considered to be greatly affected by the residence time and the size of the gas-liquid interface area, so heating more efficiently In order to carry out the process, reliable liquid hold-up and longer residence time are important. Therefore, as the distillation tower, a tray (tray) tower is preferable. Even in a packed column, the liquid hold-up is not a little, but the tray column is more reliable than the packed column in the separation effect of the acid B and water due to the salt effect and the ammonium of the acid B. The salt decomposition effect can be obtained at the same time.

  As for the tray type of the tray tower, when considering the operating range at startup and shutdown, the sheave tray in which weeping easily occurs is inferior in practice. Even if the operation rate is low or zero, a tray is preferable in which weeping hardly occurs and the liquid is reliably held on the tray. As an example of such a tray, there is a bubble bell tray. In the bubble bell tray, in order to improve gas-liquid contact on the tray, in addition to the downcomer weir, there is a weir in the gas hole on the tray on the mechanism of the bubble bell part, and the liquid depth can be maintained. Become. In addition, a tray of a type in which a hole on the tray is closed with a movable cap, such as a valve cap tray, is less likely to cause weeping and is preferable for application to the present invention.

  However, considering the temperature profile inside the tower, it is preferable to shorten the residence time for the lower part of the tower where water is stripped, because amidation occurs when the temperature becomes high with little water. Therefore, the upper part of the tower is preferably a plate tower and the lower part is preferably a packed tower. Since the ratio and the number of stages differ depending on the temperature and pressure, they are appropriately optimized.

  In order to obtain the effect of separating the acid B and water due to the salt effect in the entire apparatus, in the case of a distillation column, it is preferable to carry out the raw material from the upper part of the column, so-called extractive distillation. The stage is not particularly specified.

  The column pressure is not particularly limited, but for efficient decomposition of the acid B ammonium salt, at least the column bottom temperature should be 80 ° C or higher, preferably 115 ° C or higher and 180 ° C or lower. I must. Further, if the top of the column is lower than the melting point of the ammonium salt of acid B or the boiling point of acid B, whichever is higher, the top of the column can be regarded as a gas-liquid separation device in the separation step after the heating step. The heating step and the separation step can be performed with one apparatus, and the number of apparatuses can be reduced, which is preferable in terms of investment cost. In this case, the temperature condition at the top of the column is 114 ° C. (melting point of ammonium acetate) or lower when the ammonium salt of acid B is ammonium acetate, and 141 ° C. (boiling point of propionic acid) or lower when ammonium propionate is used. .

  The pressure condition that satisfies the conditions at the top of the column varies depending on the type and amount of acid B and alkali (earth) metal used, the amount of water, the required degree of water / acid B separation, etc. It is 2.0 atm (0.2 MPa) or less, preferably normal pressure (1 atm (0.1 MPa)) or less. In addition, the pressure conditions that satisfy the above-mentioned conditions for the bottom of the tower are the types of acid B and alkali (earth) metal and the amount of use thereof, the amount of water, the required degree of water / acid B separation, Furthermore, although it fluctuates due to a pressure loss due to a tray or a filler, it is usually 80 mmHg (10.6 kPa) or more, preferably 200 mmHg (26.7 kPa) or more.

  When supplying a raw material to a tower top part, the acid B and its salt may be distilled off by the stripping effect and entrainment (entrainment entrainment). In that case, even if the conditions of the heating operation and the separation operation can be satisfied only with the distillation tower, a gas-liquid separation device corresponding to the separation operation is added or installed for the purpose of removing the salt by stripping. It may be necessary to take measures such as lowering the steps.

  On the other hand, when separating the distillation column, which is one of the heating devices, and the gas-liquid separation device, the gas of the basic aqueous solution extracted from the top of the distillation column is once condensed by a condenser, You may supply to a liquid (gas-liquid solid, gas-solid) separation apparatus. In addition, the condenser may be a gas-liquid (gas-liquid solid, gas-solid) separation device by installing a pressure regulator in the extraction line from the top of the tower as necessary. In the former case, the supply to the gas-liquid separator is mainly liquid, but the gas-liquid may be supplied as it is. In the latter case, the supply to the gas-liquid separator is almost gas, although entrainment (entrainment) is present.

  The liquid, solid, or slurry extracted from the gas-liquid (gas-liquid solid, gas-solid) separation device is a concentrated ammonium salt of acid B distilled off mainly by the stripping effect. This is returned to the heating device for carrying out the heating step, or mixed with a freshly supplied aqueous solution of acid B or an aqueous solution of acid B, and circulated until it is decomposed.

  In the case where the distillation column in the heating step and the gas-liquid (gas-liquid solid, gas-solid) separation device in the separation step are integrated, or in the case where these are separate devices, the liquid extracted from the bottom of the column is a conventional method, It is divided into acid B and alkali (earth) metal salt of acid B by a thin film evaporator or an evaporator. Or you may extract gas from the collection | recovery part (collection stage) of the distillation tower which is a heater.

  The ammonium salt of acid B is partially amidated because it has undergone a thermal history in the process so far. This amide compound has a high boiling point, and most of the amide compound behaves like the alkali (earth) metal salt of acid B. Since the boiling point of a typical amide compound, acetamide is 222 ° C., there is almost no contamination. Even if this amide compound is slightly mixed in the acid B by entrainment or the like, it can be easily separated by a conventional method such as distillation.

  These amide compounds are hydrolyzed by the presence of alkali (earth) metal when added with water and heated. In other words, the alkali (earth) metal salt of acid B is recovered and recycled, but is mixed with a freshly supplied aqueous solution of ammonium salt of acid B or an aqueous solution of acid B. Alternatively, the amide compound is hydrolyzed and removed in advance by heating in a separate heating device, or in a distillation column as a heating device, or before being supplied to the distillation device, or in the heating device or distillation device. be able to.

  In the present invention, the type of alkali (earth) metal is not particularly limited, and one kind may be used alone, or two or more kinds may be used in combination. Among alkali metals and alkaline earth metals, alkaline metals are more advantageous because alkaline earth metals tend to have a cross-linked structure and easily cause problems of high viscosity and crystallization. Further, among alkali metals, sodium or potassium is particularly preferable when a product to which this process is applied is a food additive or a pharmaceutical use, or in consideration of economy and ease of handling. Furthermore, you may mix and use these.

  The ammonium salt of the acid B is used in an appropriate amount, for example, 0.3 to 10 times by weight, preferably 0.5 to 5 times by weight of the acid B ammonium salt in the presence of water. For example, sodium salt, potassium salt) and / or alkaline earth metal salt (for example, magnesium salt, calcium salt), pH 6.5 or higher, preferably pH 7-10 or higher, preferably 100-160 ° C. Ammonia can be vaporized by heating to a moderate temperature.

  Particularly when a reactive distillation apparatus is used, the top of the column has a pH of 7 or more, and the bottom of the column has a pH of 7 or less. Such conditions include, for example, 0.3 to 5 times, preferably 0.5 to 3 times, and 0.2 to 2 times, preferably 0.5, times the water of the acid B ammonium salt. The ammonium salt of acid B can be obtained by using an alkali metal salt (for example, sodium salt, potassium salt) and / or alkaline earth metal salt (for example, magnesium salt, calcium salt) of the acid B in an amount of ˜1.5 times by weight. Can be disassembled.

  The smaller the amount of water, the lower the energy consumption, but the easier it is to amidate. Therefore, it is appropriately controlled according to the type of acid B, the type and amount of alkali (earth) metal, the structure of the apparatus, the residence time distribution, and the like.

  In addition, the method of this invention can also be used also as an economically effective separation method of industrially important acetic acid water by mixing ammonia in acetic acid water etc. to make ammonium acetate aqueous solution. In that case, the extracted ammonia water or the vapor containing ammonia is divided into pure water and concentrated ammonia water by a conventional method, for example, distillation, etc., and the concentrated ammonia water or ammonia gas is newly supplied as an acetic acid aqueous solution. It can be recycled, can be recycled, and is particularly effective for the purification of water with a low acetic acid content.

  In the present invention, the liquid after the gas of the basic aqueous solution is extracted in the heating step is mainly composed of an alkali (earth) metal salt of acid B, free acid B obtained by decomposition, and undecomposed acid B. Contains ammonium salt. This liquid is at 125 ° C. or higher, preferably 135 ° C. or higher, more preferably 160 ° C. or higher, particularly preferably 180 ° C. or higher, under reduced pressure or normal pressure, preferably under reduced pressure, more preferably 100 mmHg or less, particularly preferably 75 mmHg or less. By heating at ˜220 ° C., the acid B can be separated and recovered. The acid B recovered in this way can be reused in the reaction crystallization step. When the pressure is sufficiently reduced (100 mmHg or less) and the reaction is performed at a high temperature (180 ° C. or more), the acid B amide compound and the unreacted ammonium salt of acid B are vaporized together with the acid B. These are separated by a conventional method (for example, distillation) to obtain a higher-purity acid B.

  The residue after separation and recovery of acid B as described above contains an alkali (earth) metal of acid B, an ammonium salt of undecomposed acid B, and a by-product acid B amide compound. This can be recycled as an alkali (earth) metal source of acid B. In this case, this residue contains an amide compound of acid B as a by-product. This is easily hydrolyzed in the presence of alkali metal and water. The residue is a by-product of acid B at a temperature of 125 ° C. or higher, preferably 140 ° C. or higher, more preferably 150 ° C. or higher after adding water or mixing a solution containing acid B and water. Amide compounds can be hydrolyzed.

  A specific apparatus configuration suitable for carrying out the method for decomposing the ammonium salt of acid B will be described below with reference to the drawings. However, the present invention is not limited to the illustrated method unless it exceeds the gist. Absent. Further, in the following, ammonium acetate is exemplified as the ammonium salt of acid B, and sodium is exemplified as the alkali (earth) metal. However, the present invention is not limited to ammonium acetate and sodium, but other acid B ammonium salts and other alkalis. Needless to say, it can also be applied to (earth) metals.

  In the method of FIG. 1, ammonium acetate and water are supplied to the distillation column 1 through the acetamide decomposition tank 3. The acetamide decomposition tank 3 is circulated with the residue (including sodium acetate, by-product acetamide and undecomposed ammonium acetate) in the subsequent thin film evaporator 4, and this residue is mixed with an aqueous ammonium acetate solution and distilled. It is fed to the tower 1 and introduced into the upper part of the distillation tower 1. In the acetamide decomposition tank 3, as described above, acetamide is hydrolyzed by mixing water with acetamide.

  The mixed solution from the acetamide decomposition tank 3 is heated and separated in the distillation column 1 under the above-described distillation conditions. From the top of the distillation column 1, a basic aqueous solution containing ammonia, water and a small amount of ammonium acetate is added. Gas distills out. The gas of the basic aqueous solution is subjected to gas-liquid separation in the vaporization tank 2 at a temperature not higher than the melting point of ammonium acetate to separate water and ammonia. The remaining ammonium acetate is fed to the acetamide decomposition tank 3 and circulated.

  The can residual liquid from the bottom of the distillation column 1 contains acetic acid, undecomposed ammonium acetate, by-products acetamide and sodium acetate, and in the thin film evaporator 4, acetic acid is separated, and the residue is acetamide. It is circulated to the decomposition tank 3.

  The method shown in FIG. 2 is different from the method shown in FIG. 1 in that the ammonium acetate fraction from the vaporization tank 2 is returned to the distillation column 1, but the heating operation and the separation operation are performed as in FIG.

  The method shown in FIG. 3 differs from the method shown in FIG. 1 in that vaporization and distillation are performed in the distillation column 1A, but the heating operation and separation operation are performed in the same manner as in FIG. Is called. In this method, the mixed solution from the acetamide decomposition tank 3 may be introduced into the vaporization section of the distillation column 1A or may be introduced into the upper portion of the distillation section.

  The method shown in FIG. 4 differs from the method shown in FIG. 1 in that the acetic acid is also separated from the middle stage in the distillation column 1B, and the thin film evaporator 4 is omitted. Heating and separation operations are performed.

  The method shown in FIG. 5 differs from the method shown in FIG. 1 in that a flash drum 5 is used instead of the distillation column, but heating and separation operations are performed in the same manner as in FIG.

  In any method, the presence of alkali (earth) metal and ammonia in a heating step such as a distillation column or a flash drum reduces the reflux ratio and can greatly reduce the energy consumed in the heating separation. .

[Recycling of separated mother liquor]
In the present invention, when the reaction crystallization is multistage, the mother liquor in the subsequent reaction crystallization is mixed with the newly supplied ammonium salt of the organic acid A as a circulating liquid such as the following (1) to (3). To do.

  (1) The mother liquor at the latter stage is circulated as it is and mixed with the ammonium salt of organic acid A that is newly supplied. The mother liquor at the latter stage contains acid B and its ammonium salt, and organic acid A and its ammonium salt. Among these, the acid B reacts with a newly supplied ammonium salt of the organic acid A to be converted into an ammonium salt of the acid B, and after crystallization of the organic acid A monoammonium salt, in the next vaporization step, Together with the ammonium salt of acid B in the mother liquor. The organic acid A and its ammonium salt are separated together with the newly supplied organic acid A ammonium salt in the reaction crystallization as the organic acid A or the monoammonium salt of the organic acid A.

  (2) After acid B is vaporized and separated from the mother liquor at the latter stage, the remaining liquid is circulated and mixed with the ammonium salt of organic acid A that is newly supplied.

  In this case, it is necessary to leave the acid B in the residue so that the residue after vaporizing and separating the acid B maintains the liquid phase. That is, it is preferable that the acid B is present in the circulating liquid so that the ammonium salt of the acid B, the organic acid A, and the ammonium salt thereof are sufficiently dissolved.

  Also in this case, as in the case of (1), the acid B in the circulating liquid reacts with the newly supplied ammonium salt of the organic acid A to be converted into an ammonium salt of the acid B, and the next vaporization step. And the ammonium salt of acid B in the latter mother liquor. Organic acid A and its ammonium salt are separated as organic acid A or monoammonium salt of organic acid A in the reaction crystallization together with newly supplied organic acid A ammonium salt.

  (3) After separating and recovering the acid B from the separated mother liquor, the ammonium salt of the acid B is vaporized to separate the organic acid A and its ammonium salt, and the ammonium salt fraction of the acid B is recycled Mixed with the ammonium salt of organic acid A fed to

  In this case, the acid B needs to be contained in the ammonium salt fraction of acid B to such an extent that the fraction maintains a liquid phase. In other words, the acid B needs to be present in the circulating fluid so that the ammonium salt of the acid B is sufficiently dissolved.

  Also in this case, as in the case of (1), the acid B in the circulating liquid reacts with the newly supplied ammonium salt of the organic acid A to be converted into an ammonium salt of the acid B, and the next vaporization step. In the crystallization mother liquor together with the ammonium salt of acid B.

  The conditions for vaporizing the acid B from the crystallization mother liquor are the same as in the case of (2) described above. In order to vaporize the ammonium salt of the acid B and separate it from the organic acid A and its ammonium salt, it is preferable to employ the same operating conditions as in the vaporization step described later. The organic acid A and its ammonium salt separated by this method are recycled to the reaction crystallization step to recover the organic acid A.

  There are no particular restrictions on the mixing conditions of the circulating liquids of (1) to (3) above and the ammonium salt of organic acid A that is newly supplied, and mixing is performed at a temperature of 20 to 140 ° C, preferably 40 to 110 ° C. It can carry out by stirring in a tank.

[Use of organic acid A]
The organic acid A, which is the target product obtained by the production method of the present invention, can be used for various applications. Among them, dicarboxylic acids can be used as raw materials for polyesters and polyamides.

  For example, oxalic acid, succinic acid, itaconic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, or lower alcohol esters thereof, succinic anhydride, adipic anhydride, etc., which are dicarboxylic acids produced according to the present invention Is a raw material for polymer polyester. In particular, succinic acid, adipic acid, sebacic acid or their anhydrides are preferred from the viewpoint of the physical properties of the polymer, but these do not impose an environmental load by microbial fermentation from a natural carbon source, It can be manufactured by applying the present invention.

  Furthermore, diols used for the production of polyester copolymers, for example, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,6 -Cyclohexanedimethanol can also be obtained by hydrogenating the organic acid A produced according to the present invention.

[Specific Preferred Embodiment]
Specific preferred embodiments of the present invention are as follows.

1. In a method for producing a dicarboxylic acid and / or tricarboxylic acid by microbial conversion of a carbon source,
Reaction containing a dicarboxylic acid and / or tricarboxylic acid ammonium salt by converting a carbon source by a microorganism in the presence of one or more neutralizing agents selected from the group consisting of ammonia, ammonium carbonate, and urea A microbial conversion step for obtaining a liquid;
Reaction crystallization for precipitating the desired dicarboxylic acid and / or tricarboxylic acid by adding monocarboxylic acid to the ammonium salt of dicarboxylic acid and / or tricarboxylic acid obtained in the microorganism conversion step Process,
And a separation step of separating the dicarboxylic acid and / or tricarboxylic acid precipitated in the reaction crystallization step. A method for producing a dicarboxylic acid and / or tricarboxylic acid.

  2. In the above 1, the dicarboxylic acid and / or characterized by having a concentration step of concentrating the reaction solution obtained in the microorganism conversion step, and subjecting the concentrate obtained in the concentration step to the reaction crystallization step A method for producing tricarboxylic acid.

3. In the above 1 or 2, after the monocarboxylic acid is vaporized and removed from the liquid after the dicarboxylic acid and / or tricarboxylic acid is separated in the separation step, the ammonium salt of the monocarboxylic acid in the liquid is vaporized and captured. Collecting and collecting the ammonium salt of the monocarboxylic acid with water and an alkali metal and / or alkaline earth metal salt of the monocarboxylic acid, followed by heating to vaporize and recover the ammonia; and
And a circulation step in which the ammonia recovered in the ammonia recovery step is used as a neutralizing agent in the microorganism conversion step. A method for producing dicarboxylic acid and / or tricarboxylic acid.

4). In a method for producing a dicarboxylic acid and / or tricarboxylic acid by microbial conversion of a carbon source,
The carbon source is one or more neutralizers selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, and alkaline earth metal carbonates. A microbial conversion step of obtaining a reaction solution containing an alkali metal and / or alkaline earth metal salt of a dicarboxylic acid and / or tricarboxylic acid by being converted by a microorganism in the presence of
By adding ammonia and carbon dioxide and / or ammonium carbonate to the alkali metal and / or alkaline earth metal salt of the dicarboxylic acid and / or tricarboxylic acid obtained in the microbial conversion step, A first reaction crystallization step of depositing an alkali metal and / or alkaline earth metal carbonate, separating the carbonate, and obtaining an aqueous ammonium salt solution of dicarboxylic acid and / or tricarboxylic acid;
A monocarboxylic acid is added to the liquid after removing the alkali metal and / or alkaline earth metal carbonate precipitated in the first reaction crystallization step to perform the target crystallization. A second reaction crystallization step for precipitating acid and / or tricarboxylic acid;
And a separation step of separating the dicarboxylic acid and / or tricarboxylic acid deposited in the second reaction crystallization step. A method for producing the dicarboxylic acid and / or tricarboxylic acid.

  5. 4. The dicarboxylic acid as described in 4 above, comprising a concentration step for concentrating the reaction solution obtained in the microorganism conversion step, and subjecting the concentrate obtained in the concentration step to the first reaction crystallization step. And / or a method for producing a tricarboxylic acid.

6). In the above 4 or 5, after monocarboxylic acid is vaporized and removed from the liquid after separating the dicarboxylic acid and / or tricarboxylic acid in the separation step, the ammonium salt of the monocarboxylic acid in the liquid is vaporized and captured. Collecting and collecting the ammonium salt of the monocarboxylic acid with water and an alkali metal and / or alkaline earth metal salt of the monocarboxylic acid, followed by heating to vaporize and recover the ammonia; and
And a circulation step of using the ammonia recovered in the ammonia recovery step as an ammonia source in the first reaction crystallization step.

7). In the method for producing dicarboxylic acid and / or tricarboxylic acid, obtaining dicarboxylic acid and / or tricarboxylic acid from ammonium salt of dicarboxylic acid and / or tricarboxylic acid,
A reaction crystallization step of precipitating dicarboxylic acid and / or tricarboxylic acid by adding monocarboxylic acid to ammonium salt of dicarboxylic acid and / or tricarboxylic acid and performing reaction crystallization;
A separation step of separating the dicarboxylic acid and / or tricarboxylic acid precipitated in the reaction crystallization step;
The ammonium salt of the monocarboxylic acid is decomposed from the liquid containing the ammonium salt of the monocarboxylic acid after separating the dicarboxylic acid and / or tricarboxylic acid in the separation step, and then the monocarboxylic acid is converted into the ammonium salt of the separated monocarboxylic acid. A step of recovering ammonia and monocarboxylic acid to obtain monocarboxylic acid and ammonia by adding an alkali metal and / or alkaline earth metal salt of
A circulation step using ammonia and monocarboxylic acid recovered in the ammonia and monocarboxylic acid recovery step as an ammonia source of the ammonium salt of the dicarboxylic acid and / or tricarboxylic acid, and a monocarboxylic acid in the reaction crystallization step, respectively; A process for producing a dicarboxylic acid and / or a tricarboxylic acid characterized by comprising:

  8). In 7 above, the ammonium salt of the dicarboxylic acid and / or tricarboxylic acid is obtained by microbial conversion of a carbon source using one or more selected from the group consisting of ammonia, ammonium carbonate, and urea as a neutralizing agent. A process for producing a dicarboxylic acid and / or a tricarboxylic acid.

  9. 7. The group according to 7, wherein the ammonium salt of the dicarboxylic acid and / or tricarboxylic acid is composed of an alkali metal hydroxide, an alkaline earth metal hydroxide, an alkali metal carbonate, and an alkaline earth metal carbonate. Dicarboxylic acid obtained by solvate method from alkali metal and / or alkaline earth metal salt of dicarboxylic acid and / or tricarboxylic acid obtained by microbial conversion of carbon source using one or more selected from And / or a tricarboxylic acid ammonium salt, wherein the dicarboxylic acid and / or tricarboxylic acid is produced.

  10. 10. The method for producing dicarboxylic acid and / or tricarboxylic acid according to any one of 1 to 9, wherein the dicarboxylic acid and / or tricarboxylic acid has 4 to 12 carbon atoms.

  11. 10. In the above 10, the dicarboxylic acid and / or tricarboxylic acid is one or two selected from the group consisting of succinic acid, adipic acid, malic acid, tartaric acid, fumaric acid, maleic acid, citric acid, aspartic acid, and glutamic acid It is the above, The manufacturing method of the dicarboxylic acid and / or tricarboxylic acid characterized by the above-mentioned.

  12 12. The method for producing a dicarboxylic acid and / or tricarboxylic acid according to any one of 1 to 11, wherein the monocarboxylic acid has 1 to 6 carbon atoms.

  13. 12. The method for producing dicarboxylic acid and / or tricarboxylic acid according to 12, wherein the monocarboxylic acid is acetic acid and / or propionic acid.

14 In the method for producing dicarboxylic acid and / or tricarboxylic acid, obtaining dicarboxylic acid and / or tricarboxylic acid from ammonium salt of dicarboxylic acid and / or tricarboxylic acid,
A reaction crystallization step of precipitating dicarboxylic acid and / or tricarboxylic acid by adding monocarboxylic acid to ammonium salt of dicarboxylic acid and / or tricarboxylic acid and performing reaction crystallization;
A separation step of separating the dicarboxylic acid and / or tricarboxylic acid precipitated in the reaction crystallization step;
A first vaporization step of further vaporizing a monocarboxylic acid from the crystallization mother liquor after separating the dicarboxylic acid and / or tricarboxylic acid in the separation step;
A method for producing a dicarboxylic acid and / or a tricarboxylic acid, comprising a second vaporization step of vaporizing ammonium monocarboxylate from the crystallization mother liquor after the first vaporization step.

  15. In 14 above, the first vaporization step is a step of vaporizing the monocarboxylic acid from the crystallization mother liquor at a temperature not higher than the melting point of the ammonium monocarboxylate, and the dicarboxylic acid and / or the tricarboxylic acid Manufacturing method.

  16. In 14 or 15, the second vaporization step comprises heating the crystallization mother liquor under a reduced pressure of 0.001 mmHg (0.133 Pa) to 200 mmHg (26.7 kPa), whereby the ammonium monocarboxylate A process for producing dicarboxylic acid and / or tricarboxylic acid, characterized by being a step of vaporizing.

  17. 17. The method for producing dicarboxylic acid and / or tricarboxylic acid according to any one of 14 to 16, wherein the dicarboxylic acid and / or tricarboxylic acid has 4 to 12 carbon atoms.

  18. 17. In the above 17, the dicarboxylic acid and / or tricarboxylic acid is selected from the group consisting of succinic acid, adipic acid, malic acid, tartaric acid, fumaric acid, maleic acid, citric acid, aspartic acid, glutaric acid, and glutamic acid Or the manufacturing method of dicarboxylic acid and / or tricarboxylic acid characterized by being 2 or more types.

  19. 19. The method for producing dicarboxylic acid and / or tricarboxylic acid according to any one of 14 to 18 above, wherein the monocarboxylic acid has 1 to 6 carbon atoms.

  20. 19. The method for producing dicarboxylic acid and / or tricarboxylic acid as described in 19 above, wherein the monocarboxylic acid is acetic acid and / or propionic acid.

21. In the method for producing dicarboxylic acid and / or tricarboxylic acid, obtaining dicarboxylic acid and / or tricarboxylic acid from ammonium salt of dicarboxylic acid and / or tricarboxylic acid,
A reaction crystallization step of precipitating dicarboxylic acid and / or tricarboxylic acid by adding monocarboxylic acid to ammonium salt of dicarboxylic acid and / or tricarboxylic acid and performing reaction crystallization;
Supplying a dicarboxylic acid and / or tricarboxylic acid ammonium salt to the reaction crystallization step;
A method for producing dicarboxylic acid and / or tricarboxylic acid having a separation step of separating dicarboxylic acid and / or tricarboxylic acid deposited in the reaction crystallization step,
A circulation step of circulating the crystallization mother liquor after separating the dicarboxylic acid and / or tricarboxylic acid in the separation step, to the supply step;
A mixing step of mixing the circulating liquid of the circulation step with an ammonium salt of dicarboxylic acid and / or tricarboxylic acid newly supplied to the supply step;
A vaporization step for vaporizing the monocarboxylic acid ammonium salt from the mixture obtained in the mixing step, and supplying the residue after the vaporization and removal of the monocarboxylic acid ammonium salt to the reaction crystallization step A process for producing a dicarboxylic acid and / or a tricarboxylic acid.

22. In the method for producing dicarboxylic acid and / or tricarboxylic acid, obtaining dicarboxylic acid and / or tricarboxylic acid from ammonium salt of dicarboxylic acid and / or tricarboxylic acid,
A reaction crystallization step of precipitating dicarboxylic acid and / or tricarboxylic acid by adding monocarboxylic acid to ammonium salt of dicarboxylic acid and / or tricarboxylic acid and performing reaction crystallization;
Supplying a dicarboxylic acid and / or tricarboxylic acid ammonium salt to the reaction crystallization step;
A method for producing dicarboxylic acid and / or tricarboxylic acid having a separation step of separating dicarboxylic acid and / or tricarboxylic acid deposited in the reaction crystallization step,
A monocarboxylic acid recovery step of vaporizing and separating the monocarboxylic acid from the crystallization mother liquor after separating the dicarboxylic acid and / or tricarboxylic acid in the separation step;
A circulation step of circulating the residual liquid after removing the monocarboxylic acid in the monocarboxylic acid recovery step to the supply step;
A mixing step of mixing the circulating liquid of the circulation step with an ammonium salt of dicarboxylic acid and / or tricarboxylic acid newly supplied to the supply step;
A vaporization step for vaporizing the monocarboxylic acid ammonium salt from the mixture obtained in the mixing step, and supplying the residue after the vaporization and removal of the monocarboxylic acid ammonium salt to the reaction crystallization step A process for producing a dicarboxylic acid and / or a tricarboxylic acid.

23. In the method for producing dicarboxylic acid and / or tricarboxylic acid, obtaining dicarboxylic acid and / or tricarboxylic acid from ammonium salt of dicarboxylic acid and / or tricarboxylic acid,
A reaction crystallization step of precipitating dicarboxylic acid and / or tricarboxylic acid by adding monocarboxylic acid to ammonium salt of dicarboxylic acid and / or tricarboxylic acid and performing reaction crystallization;
Supplying a dicarboxylic acid and / or tricarboxylic acid ammonium salt to the reaction crystallization step;
A method for producing dicarboxylic acid and / or tricarboxylic acid having a separation step of separating dicarboxylic acid and / or tricarboxylic acid deposited in the reaction crystallization step,
A first recovery step of vaporizing and separating the monocarboxylic acid from the crystallization mother liquor after separating the dicarboxylic acid and / or tricarboxylic acid in the separation step;
A second recovery step of separating dicarboxylic acid and / or tricarboxylic acid and its ammonium salt from the residual liquid after removing the monocarboxylic acid in the first recovery step;
A circulation step of circulating the residual liquid after separating the dicarboxylic acid and / or tricarboxylic acid and its ammonium salt in the second recovery step to the supply step;
A mixing step of mixing the circulating liquid of the circulation step with an ammonium salt of dicarboxylic acid and / or tricarboxylic acid newly supplied to the supply step;
A vaporization step for vaporizing the monocarboxylic acid ammonium salt from the mixture obtained in the mixing step, and supplying the residue after the vaporization and removal of the monocarboxylic acid ammonium salt to the reaction crystallization step A process for producing a dicarboxylic acid and / or a tricarboxylic acid.

  24. 24. In any one of 21 to 23 above, the number of moles of monocarboxylic acid in the circulating liquid relative to the number of moles of newly supplied dicarboxylic acid and / or tricarboxylic acid in the mixing step is 30 times or less. A process for producing a dicarboxylic acid and / or tricarboxylic acid.

  25. 25. The vaporization step according to any one of 21 to 24 above, wherein the vaporization step is performed by heating the mixed solution under a reduced pressure of 0.001 mmHg (0.133 Pa) to 200 mmHg (26.7 kPa). A method for producing a dicarboxylic acid and / or a tricarboxylic acid, which is a step of vaporizing a salt.

  26. 26. The method for producing a dicarboxylic acid and / or tricarboxylic acid according to any one of 21 to 25 above, wherein the dicarboxylic acid and / or the tricarboxylic acid has 4 to 12 carbon atoms.

  27. 26, wherein the dicarboxylic acid and / or tricarboxylic acid is selected from the group consisting of succinic acid, adipic acid, malic acid, tartaric acid, fumaric acid, maleic acid, citric acid, aspartic acid, glutaric acid, and glutamic acid Or the manufacturing method of dicarboxylic acid and / or tricarboxylic acid characterized by being 2 or more types.

  28. 28. The method for producing a dicarboxylic acid and / or tricarboxylic acid according to any one of 21 to 27, wherein the monocarboxylic acid has 1 to 6 carbon atoms.

  29. 28. The method for producing a dicarboxylic acid and / or tricarboxylic acid according to 28, wherein the monocarboxylic acid is acetic acid and / or propionic acid.

  30. In a method of decomposing monocarboxylic acid ammonium salt into monocarboxylic acid and ammonia to separate and recover monocarboxylic acid and ammonia, monocarboxylic acid ammonium salt, alkali metal and / or alkaline earth metal, and water A heating step of heating the liquid containing the gas to extract the gas of the basic aqueous solution; and a gas of the basic aqueous solution extracted from the heating step, either directly or after condensation, at a temperature below the melting point of the monocarboxylic acid ammonium salt. A method for decomposing monocarboxylic acid ammonium salt, comprising: liquid separation, gas-solid separation, or a separation step of gas-liquid solid separation.

  31. 30. In the above 30, the heating step supplies a liquid containing an ammonium monocarboxylic acid salt, an alkali metal salt of monocarboxylic acid and / or an alkaline earth metal salt or ions derived therefrom and water to a distillation column, A method for decomposing a monocarboxylic acid ammonium salt, comprising a step of extracting the gas of the basic aqueous solution from the top of the distillation column.

  32. 30 or 31 above, wherein the alkali metal and / or alkaline earth metal is one or more selected from the group consisting of Na, K, Ca, and Mg. Method.

  33. 33. The method for decomposing a monocarboxylic acid ammonium salt according to any one of 30 to 32, wherein the monocarboxylic acid is one or more selected from the group consisting of acetic acid, propionic acid and butyric acid.

  34. In any one of 30 to 33 above, the monocarboxylic acid is separated and recovered by heating the liquid after extracting the gas of the basic aqueous solution in the heating step at 125 ° C. or higher under reduced pressure or normal pressure. A method for decomposing a monocarboxylic acid ammonium salt, comprising a carboxylic acid recovery step.

  35. 34. Decomposition of monocarboxylic acid ammonium salt according to 34, wherein in the monocarboxylic acid recovery step, the monocarboxylic acid ammonium salt and water are mixed with the residue from which the monocarboxylic acid has been separated and circulated to the heating step. Method.

  36. 35. The method for decomposing ammonium monocarboxylic acid salt as described in 35 above, wherein the residue is mixed with ammonium monocarboxylic acid salt and water, preheated to 90 ° C. or higher, and then recycled to the heating step.

  Hereinafter, the present invention will be described more specifically with reference to examples.

  In Example 1-1 below, diammonium oxalate (Wako Pure Chemical Industries, Ltd.) was used as an alternative material for the concentrate obtained by concentrating the ammonium salt of organic acid A obtained from the microorganism conversion step in the concentration step. Made). As acid B, acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.) or propionic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was used.

Example 1-1
180 g of diammonium oxalate (78 wt% oxalic acid, 22 wt% ammonia) was dissolved in 720 g of water to prepare 900 g of a 20 wt% ammonium oxalate solution.

  This aqueous solution was evaporated and concentrated by an oil bath at 140 ° C. (100 ° C. in the evaporator) and concentrated to 256.5 g. From this, 249 g was collected, and 173 g of acetic acid was added to oxalic acid, followed by thorough stirring. This (415.5 g charged) was put into a crystallizer and kept at 100 ° C. for 10 minutes, and then kept at 40 ° C. for 18 hours while stirring was continued.

  Subsequently, after suction filtration, solid content was taken out. The filtrate was 296.6 g and the solid content was 93.4 g. The obtained solid content was analyzed for organic substances by liquid chromatography and for ammonia by ion chromatography. As a result, 28.4 g% by weight of acetic acid, 58.3% by weight of oxalic acid, and 10.4% by weight of ammonia were found. Although the total did not reach 100%, it is considered a measurement error because ammonia and organic substances are analyzed separately. Similarly, the mother liquor was 59.9% by weight acetic acid, 25.3% by weight oxalic acid, and 6.7% by weight ammonia.

Since it is not considered that so much acetic acid in the mother liquor is attached, it is considered that a considerable amount of ammonium acetate is coprecipitated. Therefore, the molar ratio (assuming 100 g) was calculated as follows.

  Assuming that 60% of the acetic acid is ammonium acetate (28 mol), there are 33 mol of ammonia and 98 mol of carboxylic acid of oxalic acid, and already 16 mol (1/3 of the obtained solid) is salt-decomposed. It turns out that it is an acid itself and others are monoammonium oxalate salts. Actually, the mother liquor also contains ammonia, so it is considered that salt decomposition has progressed further by reaction crystallization.

  Further, 90 g of the obtained solid was dissolved in 80 g of acetic acid at around 80 ° C., and this (165 g) was put into a crystallizer and held at 80 ° C. for 10 minutes, and then stirred at 40 ° C. for 7 hours. Retained.

Subsequently, after suction filtration, solid content was taken out. The filtrate was 129.6 g and the solid content was 16.2 g. The obtained solid content was analyzed for organic substances by liquid chromatography and ammonia by ion chromatography. As a result, acetic acid was 10.9% by weight, oxalic acid was 87.4% by weight, and ammonia was 2.8% by weight. Similarly, the mother liquor was 90.2% by weight acetic acid, 25.2% by weight oxalic acid, and 6.0% by weight ammonia.

  In this example, oxalic acid could be obtained from ammonium oxalate without using electrodialysis or inorganic acid, and it was confirmed that it was decomposed into oxalic acid only by reaction crystallization.

Example 1-2
Using a 100 ml reagent bottle, 15.2 g (0.1 mol) of diammonium oxalate was mixed with 15.2 g (0.25 mol) of acetic acid and 6 g of water while heating and dissolved at 90 ° C. This was left in a water bath (40 ° C.) for 12 hours. A white solid precipitated out and was filtered. The recovered solid was 6.1 g, and as a result of analysis, oxalic acid was 69% by weight and ammonia was 12.8% by weight.

  3.1 g of this solid was again put into a 100 ml reagent bottle, mixed by heating to 5.4 g of acetic acid, and dissolved at 75 ° C. This was left in a water bath (40 ° C.) for 8 hours. A white solid precipitated out and was filtered. The recovered solid was 0.5 g, and as a result of analysis, it was 97% by weight of succinic acid and 1.6% by weight of ammonia.

Example 1-3
Using a 100 ml reagent bottle, 15 g (0.1 mol) of diammonium oxalate was mixed with 35 g (0.58 mol) of acetic acid and 10 g of water while heating and dissolved at 95 ° C. This was left in a water bath (40 ° C.) for 12 hours. A white solid precipitated out and was filtered. The recovered solid was 4.3 g.

  4 g of this solid was again put into a 100 ml reagent bottle, heated and mixed with 16 g of acetic acid, and dissolved at 70 ° C. This was left at room temperature (about 15 ° C.) for 8 hours. A white solid precipitated out and was filtered. The recovered solid was 2.2 g, and as a result of analysis, it was 90% by weight of oxalic acid and 0.8% by weight of ammonia.

  From the above results, it is clear that high purity oxalic acid could be recovered by reaction crystallization with acetic acid.

Example 1-4
50.35 g of diammonium oxalate and 269.72 g of acetic acid were put into a crystallizer, dissolved at 85 ° C. and held for 10 minutes, and then cooled to 15 ° C. while stirring was continued. In 22 minutes after cooling to 15 ° C., 1.03 g of reagent oxalic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a seed crystal and held for 4 hours.

299.8 g of the filtrate and 13.1 g of the solid were recovered. The obtained solid content was analyzed for organic substances by liquid chromatography and for ammonia by ion chromatography. As a result, acetic acid was 19.5% by weight, oxalic acid was 82.4% by weight, and ammonia was 1.1% by weight. Similarly, the mother liquor was 80.7 wt% acetic acid, 9.9 wt% oxalic acid, and 4.0 wt% ammonia.

Example 1-5
50.46 g of diammonium adipate (manufactured by Wako Pure Chemical Industries, Ltd.) and 269.83 g of acetic acid were placed in a crystallizer, dissolved at 85 ° C. and held for 10 minutes, and then cooled to 15 ° C. while stirring was continued. Precipitation started immediately and was maintained for 4 hours and 23 minutes.

253.4 g of the filtrate and 55.4 g of the solid were recovered. The obtained solid content was analyzed for organic substances by liquid chromatography and for ammonia by ion chromatography. As a result, acetic acid was 47.1% by weight, adipic acid was 61.8% by weight, and ammonia was 2.0% by weight. Similarly, the mother liquor was 85.0% by weight acetic acid, 5.1% by weight adipic acid, and 3.7% by weight ammonia.

50.21 g of the obtained solid content was washed with 149.78 g of acetic acid at 16 ° C. for 30 minutes and filtered. The obtained solid was 25.9 g, and the rinse liquid was 169.5 g. Analysis of the solid revealed 11.6 wt% acetic acid, 80.3% adipic acid, and 0.2 wt% ammonia. Similarly, the rinse solution was 89.4% by weight acetic acid, 3.9% by weight adipic acid, and 0.5% by weight ammonia.

Example 1-6
6.08 g of monoammonium glutamate (manufactured by Sigma) was dissolved in 10.08 g of water. 399.69 g of acetic acid was put in a crystallizer and kept at 60 ° C., and 15.72 g of monoammonium glutamate aqueous solution was put therein. Immediately, cloudiness started, and the mixture was cooled to 16 ° C. while stirring was continued. It was kept at 16 ° C for 4 hours and 18 minutes.

387.1 g of the filtrate and 19.3 g of the solid were recovered. The obtained solid content was analyzed for organic substances by liquid chromatography and ammonia by ion chromatography. As a result, acetic acid was 68.2% by weight, glutamic acid was 24.7% by weight, and ammonia was 0.15% by weight. Similarly, the mother liquor contained 92.3% by weight of acetic acid, no glutamic acid was detected, and 1.4% by weight of ammonia. The remainder of the mother liquor is estimated to be water.

Example 1-7
Using a 100 ml reagent bottle, 50% of 28% aqueous ammonia (manufactured by Kanto Chemical Co.) (0.83 mol of ammonia ) was added to 15 g (0.086 mol) of suberic acid (Acros organics ) and dissolved. This was dried under reduced pressure at 80 ° C. to obtain a salt. Analysis revealed that 77% by weight of suberic acid, 9.2% by weight of ammonia and 62% of the carboxyl groups of suberic acid were ammonium salts.

5.01 g of this ammonium suberic acid salt was dissolved in 25.05 g of acetic acid while heating, and this was left in a constant temperature bath at 15 ° C. for 18 hours. A white solid precipitated out and was filtered. The recovered solid was 0.46 g, and as a result of analysis, it was 55% by weight of suberic acid, 40% by weight of acetic acid, and 0.2% by weight of ammonia. The mother liquor was 29.60 g, and as a result of analysis, it was 2.6% by weight of suberic acid, 93% by weight of acetic acid, and 1.3% by weight of ammonia.

Example 1-8
50.20 g of diammonium adipate (manufactured by Wako Pure Chemical Industries, Ltd.) and 399.29 g of acetic acid were put in a crystallizer, dissolved at 95 ° C. and held for 10 minutes, and then cooled to 15 ° C. while stirring was continued. After 55 minutes from 15 ° C., 0.5 g of adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a seed crystal. The solution was kept for 3 hours and filtered.

420.5 g of mother liquor (filtrate) and 25.65 g of solid were recovered. The obtained solid content was analyzed for organic substances by liquid chromatography and ammonia by ion chromatography. Propionic acid was 35.3 wt%, adipic acid was 56.8 wt%, and ammonia was 5.5 wt%. Similarly, the mother liquor was 90.6% by weight propionic acid, 6.2% by weight adipic acid, and 2.2% by weight ammonia.

The obtained solid content of 25.2 g was dissolved at 95 ° C. using 99.99 g of propionic acid, and then cooled at 15 ° C. Precipitation started immediately. The solution was kept for 3 hours and 53 minutes and filtered. The obtained solid was 16.48 g, and the mother liquor was 104.4 g. Analysis of the solid revealed 28.2% by weight of propionic acid, 69.0% of adipic acid, and 0.4% by weight of ammonia. Similarly, the mother liquor was 94.4% by weight of propionic acid, 3.3% by weight of adipic acid, and 1.1% by weight of ammonia.

Example 2
Below, distillation experiments of monocarboxylic acid and monocarboxylic acid ammonium salt are listed.

[Preparation of model mother liquor]
(1) Preparation of model mother liquor 1 The composition of the mother liquor after reaction crystallization is affected by the amount of solvent in reaction crystallization and the purity of the solvent at the time of recycling, and is determined by optimum operating conditions depending on conditions such as utilities. In order to see the difference in separation performance based on the melting point of the monocarboxylic acid ammonium salt, as described in JP-A No. 2002-135656, the monocarboxylic acid is preferably acetic acid having 1 to 6 carbon atoms. I chose. The type of di / tricarboxylic acid has a slightly different effect on the boiling point, but does not affect the separation of the monocarboxylic acid and the monocarboxylic acid ammonium salt. In this experimental example, di / tricarboxylic acid was selected using succinic acid as a standard substance.

  When the solubility of ammonium oxalate in acetic acid was confirmed, it was dissolved up to a concentration of 33 wt% at 100 ° C. and 10 wt% at 16 ° C. Therefore, if the temperature of industrial water is about 20 ° C, it is estimated that the crystallization temperature will be about 30-50 ° C, and it is estimated that a concentration of about 20 wt% will remain in the crystallization mother liquor after the crystallization operation. .

であることから、琥珀酸ジアンモニウムは酢酸と反応し、このモデル母液１は

に対して、凡そ以下のような組成になっていると考えられる。

Therefore, assuming a crystallization mother liquor in which oxalic acid was precipitated by reaction crystallization with acetic acid and separated, about 120 g of acetic acid manufactured by Wako Pure Chemical Industries, Ltd. and about 30 g of ammonium oxalate manufactured by Wako Pure Chemical Industries, Ltd. were mixed. A model mother liquor 1 having a concentration of about 20% ammonium oxalate that was completely dissolved by heating was used. As mentioned above,

Therefore, diammonium oxalate reacts with acetic acid, and this model mother liquor 1

On the other hand, it is considered that the composition is as follows.

(2) Preparation of model mother liquid 2 Propionic acid manufactured by Wako Pure Chemical Industries, diammonium oxalate manufactured by Wako Pure Chemical Industries, and 28% ammonia water manufactured by Wako Pure Chemical Industries, Ltd. were mixed in the following composition and heated to dissolve completely. Was designated as “model mother liquor 2”.

であることから、琥珀酸ジアンモニウムはプロピオン酸と反応し、凡そ以下のような組成になっていると考えられる。

This model mother liquor 2 is

Therefore, it is considered that diammonium oxalate reacts with propionic acid and has the following composition.

[Distillation experiment]
Experimental Example 2-1: Lower temperature limit Model mother liquor 1 (120.00 g of acetic acid, 30.42 g of diammonium oxalate) was prepared, then placed in a 200 ml eggplant-shaped flask, placed in a simple distillation apparatus, and simply distilled at 10 mmHg. . The condenser used was a water-cooled type. The single distillation apparatus was constantly supplied with a small amount of nitrogen gas for the purpose of preventing bumping and increasing the distillation efficiency.

  Distillation started when the temperature in the flask was 36 ° C, and almost no fraction was removed at 69 ° C. Precipitation occurred in the flask and solidified.

  The amount distilled off was 40 ml (45.65 g). The internal volume of the flask was 64.78 g from the tare of the flask and the subtraction before and after the experiment. The rest of the temperature of the refrigerant water in the condenser was higher than the degree of decompression, so it was considered that the condenser did not fully condense and escaped from the decompression line to the draft.

Experimental Example 2-2: Upper limit temperature After preparing model mother liquor 1 (acetic acid 120.18 g, diammonium oxalate 30.40 g), this was placed in a 200 ml eggplant-shaped flask, placed in a simple distillation apparatus, and simply distilled at 150 mmHg. . The condenser used was a water-cooled type. The single distillation apparatus was constantly supplied with a small amount of nitrogen gas for the purpose of preventing bumping and increasing the distillation efficiency.

  Distillation started when the temperature in the flask was 85 ° C., and the temperature of the oil bath reached 105 ° C. during the process. The distillation amount became 40 ml in 1 hour and 45 minutes. Here, the first fraction sample was collected. At this time, the temperature in the flask was 89 ° C., and the pressure was 120 mmHg.

  After that, when the distillation stopped, the operation of reducing the pressure was repeated so that the temperature of the flask did not exceed 100 ° C. The temperature of the oil bath was operated in consideration of errors and fluctuations of the thermometer so that the melting point (114 ° C) was not exceeded, and 109 ° C was the maximum. One hour and 47 minutes were spent from the first sampling, and when 40 ml was distilled off, a sample was collected. At this time, the temperature in the flask was 95 ° C., and the pressure was 60 mmHg.

  The pressure was returned to normal pressure, and 2.55 g of the remaining can sample was collected. The internal volume of the flask was 64.96 g from the tare of the flask and the subtraction before and after the experiment. Crystals did not precipitate throughout the time of simple distillation.

Experimental Example 2-3: Over-temperature After preparing the model mother liquor 1 (acetic acid 120.03 g, diammonium oxalate 30.41 g), this was placed in a 200 ml eggplant-shaped flask, placed in a simple distillation apparatus, and simply distilled at 380 mmHg. . The condenser used was a water-cooled type. The single distillation apparatus was constantly supplied with a small amount of nitrogen gas for the purpose of preventing bumping and increasing the distillation efficiency.

  Distillation started when the temperature in the flask was 110 ° C., and after about 1 hour, 114 ° C. and then the distillation rate did not increase, and in 45 minutes, the amount of distillation became 40 ml (corresponding to Experimental Example 2-1). Here, the first fraction sample was collected. The temperature at this point was 118 ° C. When 40 ml was further distilled off (132 ° C .: 1 hour and 10 minutes after the first sampling), the pressure was once returned to normal pressure, and a second fraction sample and 2.55 g of the can residue sample were collected. The pressure was reduced again to 380 mmHg, and the reaction was completed when 2.97 g was distilled off. The internal volume of the flask was 54.47 g from the tare of the flask and the subtraction before and after the experiment. Crystals did not precipitate throughout the time of simple distillation.

Experimental Example 2-4: Effect of water 30.40 g of oxalic acid was used as in the model mother liquor 1. This was dissolved in 72.02 g of acetic acid and 48.01 g of water instead of 120 g of acetic acid in model mother liquor 1.

  This was put into a 200 ml eggplant type flask, placed in a simple distillation apparatus, and simple distilled at normal pressure. The condenser used was a water-cooled type. The single distillation apparatus was constantly supplied with a small amount of nitrogen gas for the purpose of preventing bumping and increasing the distillation efficiency.

  Distillation started when the temperature in the flask was 132 ° C. (oil bath temperature 158 ° C.), and 40 ml (42.64 g) was distilled off in 20 minutes, and a sample was collected. Furthermore, 40 ml (41.88 g) was distilled off over 34 minutes (flask temperature 150 ° C., oil bath 180 ° C.), and a sample was collected. At this time, 2.71 g was sampled from the remaining can. Further, the heating was continued, and when 20 ml (22.08 g) was distilled off (the temperature in the flask was 169 ° C. and the oil bath was 206 ° C.), it was stopped, and the fraction and the remaining residue were sampled. From the tare of the flask and the subtraction before and after the experiment, the balance of the can was 39.27 g.

Experimental Example 2-5: Propionic acid The model mother liquor 2 was placed in a 200 ml eggplant-shaped flask, placed in a simple distillation apparatus, and heated under reduced pressure after 100 mmHg. The condenser used was a water-cooled type. The single distillation apparatus was constantly supplied with a small amount of nitrogen gas for the purpose of preventing bumping and increasing the distillation efficiency.

  Distillation began when the temperature in the flask reached 72 ° C. When the temperature in the flask reached 83 ° C., the pressure was reduced so that the temperature was maintained, and the pressure was reduced to 50 mmHg. Thereafter, when the temperature reached 90 ° C., the fraction was sampled 55 minutes after the start of distillation. At this time, the temperature of the oil bath was 100 ° C. One hour after the start of distillation, the temperature of the oil bath was raised to 105 ° C for 20 minutes, and further raised to 108 ° C for 20 minutes. Was sampled. The temperature in the flask at the end of the distillation was 95 ° C.

  The collected fraction was 37.0 g for the first time, 15.25 g for the second fraction, and 79.7 g for the remainder of the can.

である。 In Experimental Example 2-5, the same standard as at the time of analysis, that is, assuming that the acid and the base exist separately,

It is.

Experimental Example 2-6: Vaporization and Minimum Temperature of Ammonium Acetate In consideration of the results of Experimental Examples 2-1 and 2-2, the vaporization of ammonium acetate in the acetic acid-oxalic acid system was verified using the following model solution.

  Acetic acid 29.99g, ammonium oxalate 15.19g, and ammonium acetate 7.69g were put into a 200ml eggplant type flask in order to grasp the evaporation of ammonium acetate more accurately, and this was installed in a rotary evaporator. The pressure was reduced to 30 mmHg, and the mixture was heated for 27 minutes in an oil bath heated to 108 ° C.

  A white solid was deposited on the condenser portion. In the can residue, a white solid precipitated and solidified, and its amount was 27.93 g.

である。 The same standard as at the time of analysis, that is, assuming that acid and base exist separately,

It is.

Experimental Example 2-7: Vaporization of ammonium acetate / maximum temperature As a result of Experimental Examples 2-1 and 2-2, it may be more advantageous to add moisture under high temperature conditions from Experimental Examples 2-3 and 2-4. Based on the above discussion, the vaporization of ammonium acetate in the acetic acid-succinic acid system was verified using the following model solution.

  Acetic acid 24.00g, ammonium oxalate 15.20g, ion-exchanged water 6.11g, and ammonium acetate 7.68g was placed in a 200ml eggplant-shaped flask in order to more accurately grasp the vaporization of ammonium acetate, and this was placed in a rotary evaporator. . The pressure was reduced to 150 mmHg, and the oil bath was heated to 150 ° C and heated to 178 ° C. Although the distillation rate immediately decreased, the mixture was heated for 30 minutes in consideration of the comparison with Experimental Example 2-6.

  A white solid was deposited on the condenser portion. In the can residue, a white solid was precipitated and solidified, and its amount was 16.07 g.

である。 The same standard as at the time of analysis, that is, assuming that acid and base exist separately,

It is.

Experimental Example 2-8: Design Value 30.00 g of acetic acid, 15.18 g of ammonium oxalate, and 7.71 g of ammonium acetate were placed in a 200 ml eggplant-shaped flask to more accurately grasp the vaporization of ammonium acetate. installed. The pressure was reduced to 50 mmHg and the oil bath was heated to 100 ° C. Distillation began at an oil bath temperature of 132 ° C., and after 25 minutes, the residue was precipitated and solidified at 139 ° C. The remaining amount of the can was 22.71 g. A white solid was deposited on the condenser portion.

The same standard as at the time of analysis, that is, assuming that acid and base exist separately,

Experimental Example 2-9: Effect of water Based on the results of Experimental Examples 2-1 and 2-2, and further based on the consideration that adding water from Experimental Examples 2-3 and 2-4 is more advantageous. Assuming conditions where water was added to the deposition solvent or the conditions were added, the vaporization of ammonium acetate in the acetic acid-oxalic acid system was verified using the following model solution.

  7.50 g of acetic acid, 15.23 g of ammonium oxalate, 35.99 g of ion-exchanged water, and 7.68 g of ammonium acetate were placed in a 200 ml eggplant-shaped flask to more accurately grasp the vaporization of ammonium acetate, and this was placed on a rotary evaporator. . The pressure was reduced to 50 mmHg and the oil bath was heated to 137 ° C. The temperature of the oil bath changed from 137 to 138 ° C. during the experiment.

  After 17 minutes, a white solid precipitated and solidified in the can residue, and the amount was 27.96 g. A white solid was deposited on the condenser portion.

である。 The same standard as at the time of analysis, that is, assuming that acid and base exist separately,

It is.

Experimental Example 2-10: Vaporization of ammonium propionate Ammonium propionate is not commercially available. Therefore, 39.99 g of propionic acid, 15.23 g of ammonium oxalate, and 15.16 g of 28% aqueous ammonia from Wako Pure Chemical Industries, Ltd. were used as model solutions.

  This was put into an eggplant-shaped flask, and this was set in a rotary evaporator. The pressure was reduced to 40 mmHg and the oil bath was heated to 157 ° C. During the experiment, the temperature was 160 ° C. In this state, it was distilled off for 25 minutes.

  A white solid was deposited on the condenser portion. In the can residue, a white solid was precipitated and solidified, and its amount was 25.38 g.

である。 The same standard as at the time of analysis, that is, assuming that acid and base exist separately,

It is.

[result]
The results of the above distillation experiments are summarized in Tables 25-28.

[Discussion]
In the oxalic acid-acetic acid system, the ammonium salt of acid B refers to ammonium acetate, and it is known that its melting point is 114 ° C. In Experimental Example 2-3, the oil bath was 134 ° C. to 149 ° C., and the liquid temperature in the flask exceeded 114 ° C., and the maximum was 132 ° C. The elapsed time was about 2 hours. At this time, acetamide was generated as much as 7.4 wt%. Furthermore, oxalic acid amide and the like were generated, and oxalic acid was charged with 30.4 g (corresponding to 0.2 mol) as ammonium oxalate. It is reduced to 0.09mol equivalent. On the other hand, in Experimental Example 2-2, the oil bath temperature, that is, the wall temperature of the flask reached a maximum of 109 ° C., and the liquid temperature in the flask was 95 ° C., and it took 3.3 hours. Nevertheless, only 0.4 wt% of acetamide was produced. Similarly, oxalic acid was 0.186 mol in the state that it was not detected in the fraction, compared to 30.4 g (equivalent to 0.2 mol) of ammonium oxalate. The difference was obvious.

  From this result, the inventor found that the ammonium carboxylate was higher than the liquid temperature of 95 ° C. in Experimental Example 2-2, the liquid temperature of 132 ° C. or lower in Experimental Example 2-3, and the average temperature during operation was around 120 ° C. It was thought that there was a temperature that had a specific influence on the reaction to be converted.

  The melting point of ammonium acetate is 114 ° C., and the melting point of ammonium propionate is considered to be about 100 ° C. as described above.

  In this experiment, the operating temperature is assumed to be approximately the melting point or slightly above the melting point. Therefore, especially in the fraction 2, it is considered that ammonia has slightly evaporated due to thermal decomposition. However, since the temperature in the flask is mostly 95 ° C. or less during most of the elapsed time, it is observed that amidation does not proceed extremely. In the case of acetic acid in Experimental Example 2-2, the residence time exceeds 3 hours, and about 1 and a half hours is 90 ° C or higher. In the case of Experimental Example 2-5, considering that it is about 40 minutes, the amidation rate can be regarded as almost the same within the range of analysis error.

  It is important to take out acetic acid or propionic acid as the acid B without containing ammonia, and concentrate the organic acid A and its ammonium salt without amidation or imidization. For that purpose, it is necessary to use the reaction singularity around 110 ° C. or the melting point of acid B, whichever is lower. Therefore, in the case of acetic acid, the reaction singularity is not exactly known, and since it is almost the same temperature as the melting point, the operating conditions of acetic acid at a melting point of 114 ° C. or lower, the case of propionic acid, the melting point of propionic acid is unknown. Yes, because the volatilization amount of ammonia in the experimental example is a long residence time of 1 hour and 40 minutes, it is 1/10 or less of the charged amount, which is considered acceptable in practice. The upper and lower temperatures may be considered before and after this experimental example. In other words, the temperature of the wall surface (oil bath temperature) is 110 ° C. Since the wall temperature is not generally measured, 110 ° C is the upper limit of the utility temperature used for heating. Considering the liquid temperature, it is 100 ° C., which may be considered to be equivalent to the melting point of ammonium propionate. When propionic acid is used, the operating condition is that the temperature of the process fluid is 100 ° C. or less. It only has to satisfy the operating conditions of either utility or process fluid.

  Further, Experimental Examples 2-3 and 2-4 were performed as comparative examples. This is based on the consideration that the amidation or imidation reaction may be inhibited particularly when water is contained. Under the conditions of Experimental Examples 2-1 and 2-2, amidation and imidation are slight, and it is difficult to clearly indicate a significant difference within the range of analysis error. It is verified with. Looking at the results, there was clearly a significant difference. Therefore, it can be said that it is desirable to have some water when the acid B is vaporized.

  When acid B is vaporized from the crystallization mother liquor and then the method for vaporizing the ammonium salt of acid B is tested, the residence time cannot be ignored. As described above, the amidation reaction is rapidly accelerated at around 120 ° C., while on the other hand, separation of the ammonium salt of the acid B from the organic acid A and its ammonium salt requires a higher temperature. This is because the melting point of the ammonium salt of B is ideal.

  In the case of a simple distillation apparatus, the connection part from the flask, which is a heating part, to the condenser part is exposed to the outside air, and heat exchange occurs between the outside air and the process, causing internal reflux. As a result, the residence time increases unless the difference between the heat dissipation of the connection and the heating of the flask is significantly large. In Experimental Example 2-3, the temperature of the oil bath is increased at a stretch, and the reason why the residence time becomes long despite the large heating amount is that the temperature difference between the process and the outside air is also high, so the heat dissipation amount at the connection is the same. This is because it becomes larger.

  Therefore, the present inventor conducted an experiment using a rotary evaporator. In the rotary evaporator, the flask is installed obliquely with respect to the oil bath and can be heated evenly to the vicinity of the connection portion of the flask by rotating. In addition, the connecting portion of the flask to the condenser are shielded from the outside air by the driving portion, and heat exchange with the outside air is substantially reduced. As a result, the internal reflux is extremely small and the residence time can be shortened.

  However, the liquid temperature in the rotating flask cannot be measured. Because, in order to shorten the residence time, the amount of charge is intentionally smaller than the size of the flask, so even if a thermometer can be put, the liquid level is always near the inner wall of the flask, This is because the liquid temperature cannot be measured stably. Further, since the organic acid A and their ammonium salts are solidified at the final stage of evaporation and evaporation, it is difficult to measure the temperature in the flask.

  Since the ammonium salt of acid B undergoes thermal decomposition, accurate physical properties such as boiling point cannot be measured. However, the present inventor thinks that theoretically there is always a boiling point and there is a phenomenon such as sublimation, and that the contribution of evaporation and sublimation cannot be strictly separated from that due to thermal decomposition. It was.

  Therefore, an experiment was conducted to vaporize the ammonium salt of acid B by using a reduced pressure system and shortening the residence time. Experimental Example 2-6, Experimental Example 2-7, and Experimental Example 2-8 are experiments using a rotary evaporator.

  In Experimental Example 2-6, it was discovered that by sufficiently reducing the pressure, ammonium acetate was vaporized by using an oil bath of about 110 ° C., that is, a heat source. This is a phenomenon below the melting point, and it is estimated that sublimation occurs. In Experimental Example 2-7, ammonium acetate is sufficiently vaporized even under a relatively mild decompression condition of 150 mmHg. In the actual process, the residence time can be shortened, and it has been proved that the design is sufficiently possible even under this condition. However, although the oil bath, that is, the heat source is set to 180 ° C., for the purpose of comparison in this experiment, the time was extended to that of Experimental Example 2-6, and thus amidation is somewhat occurring. The higher the temperature of the heat source suggests that the residence time must be correspondingly shortened.

  In Experimental Example 2-9, since water quickly evaporated, it is difficult to specify whether the amidation was suppressed because of the short time or whether the dehydration reaction was suppressed due to the presence of water. However, both effects were considerable, and it was confirmed only that amidation was lowered by the presence of water.

  Therefore, as a method for vaporizing the acid B after concentrating the crystallization mother liquor, one with a short heating time is preferable. Further, it is preferable to vaporize in an overheated state, that is, to heat the process fluid under a reduced pressure condition and a sufficiently high temperature heat source.

Example 3
Experimental Example 3-1: Experiment for confirming the presence of ammonium acetate (separation by rotary evaporator)
6.0 g of acetic acid manufactured by Wako Pure Chemical Industries, 15.18 g of ammonium oxalate manufactured by Wako Pure Chemical Industries, and 20 g of water were placed in a 200 ml eggplant-shaped flask, and this was placed on a rotary evaporator. The pressure was reduced to 50 mmHg, and the temperature was raised by attaching to an oil bath heated to 140 ° C. The distillation time was 5 minutes.

  A white solid was deposited on the condenser portion. The balance of the can was 20.8 g. The composition of this solid was 56.1% by weight (0.099 mol) of succinic acid, 19.6% by weight (0.068 mol) of acetic acid, and 15.4% by weight (0.189 mol) of ammonia.

Experimental Example 3-2: Reaction Crystallization Using a 100 ml reagent bottle, 4.5 g (0.03 mol) of diammonium oxalate was mixed with 30 g (0.5 mol) of acetic acid while heating and dissolved at 80 ° C. did. This was left at room temperature (17 ° C.) for 2 hours. A white solid precipitated out and was filtered. The recovered solid was 1.92 g, and as a result of analysis, it was confirmed that it was 96% by weight of succinic acid and 1% by weight of ammonia.

であることから、琥珀酸アンモニウムの1価目は酢酸と反応し、

に対して、凡そ以下のような組成になっていると考えられる（アンモニアとして2重量％）。

Experimental Example 3-3 Gas-Liquid Separation / Concentration after Crystallization 120 g of acetic acid manufactured by Wako Pure Chemical Industries, Ltd. and 30 g of ammonium oxalate manufactured by Wako Pure Chemical Industries, Ltd. were mixed and heated to obtain a crystallization mother liquor. Also,

Therefore, the first valence of ammonium oxalate reacts with acetic acid,

On the other hand, it is considered that the composition is as follows (2% by weight as ammonia).

  This was placed in a 200 ml eggplant-shaped flask, placed in a simple distillation apparatus, and simply distilled at 150 mmHg. The condenser used was a water-cooled type. The single distillation apparatus was constantly supplied with a small amount of nitrogen gas for the purpose of preventing bumping and increasing the distillation efficiency.

  Distillation started when the temperature in the flask was 85 ° C., and the temperature of the oil bath reached 105 ° C. during the process. The distillation amount became 40 ml in 1 hour and 45 minutes. Here, the first fraction sample was collected. At this time, the temperature in the flask was 89 ° C., and the pressure was 120 mmHg.

  After that, when the distillation stopped, the operation of reducing the pressure was repeated so that the temperature of the flask did not exceed 100 ° C. The temperature of the oil bath was operated in consideration of errors and fluctuations of the thermometer so that the melting point (114 ° C) was not exceeded, and 109 ° C was the maximum. 1 hour and 34 minutes (total time 3 hours and 19 minutes) were spent from the first sampling, and a sample was collected when 40 ml was distilled off. At this time, the temperature in the flask was 95 ° C., and the pressure was 60 mmHg.

  The pressure was returned to normal pressure, and a can sample was taken. The internal volume of the flask was 64.96 g from the tare of the flask and the subtraction before and after the experiment. Crystals did not precipitate throughout the time of simple distillation.

  The first distillate composition is 102% acetic acid (exceeding 100% due to analysis error), and the second distillate composition is 103% acetic acid (exceeding 100% due to analysis error). The composition was 54% acetic acid, 0.4% acetamide, 34% oxalic acid, 1.8% oxalic acid monoamide, and 9.8% ammonia.

Experimental Example 3-4 Gas / Liquid / Gas-Solid Separation Obtaining Di / Tricarboxylic Acid and Its Ammonium Salt Salt The vaporization of ammonium acetate in an acetic acid-succinic acid system was verified using the following model solution.

  Wako Pure Chemicals 30.00g, Wako Pure Chemicals Ammonium Succinate 15.18g, and Wako Pure Chemicals Ammonium Acetate 7.71g in a 200ml eggplant flask This was installed in a rotary evaporator. The pressure was reduced to 50 mmHg, and the oil bath was heated to 100 ° C. and heated to 140 ° C. Distillation began when the oil bath reached 132 ° C. The distillation time was 17 minutes.

  A white solid was deposited on the condenser portion. The remainder of the can was 22.71 g.

  The composition of the can residue was 34% acetic acid, 0.3% acetamide, 54% oxalic acid, 0.7% oxalic acid monoamide, and 12.7% ammonia.

であることから、琥珀酸アンモニウムの1価目は酢酸と反応し、

に対して、凡そ以下のような組成になっていると考えられる。

Experimental Example 3-5: Conditions for amidation 120 g of acetic acid manufactured by Wako Pure Chemical Industries, Ltd. and 30 g of ammonium oxalate manufactured by Wako Pure Chemical Industries, Ltd. were mixed, heated and completely dissolved to obtain a crystallization mother liquor. Also,

Therefore, the first valence of ammonium oxalate reacts with acetic acid,

On the other hand, it is considered that the composition is as follows.

  This was put into a 200 ml eggplant-shaped flask, placed in a simple distillation apparatus, and simply distilled at 380 mmHg. The condenser used was a water-cooled type. The single distillation apparatus was constantly supplied with a small amount of nitrogen gas for the purpose of preventing bumping and increasing the distillation efficiency.

  The first drop was distilled off at a temperature of 110 ° C. in the flask, but the distillation rate was remarkably reduced due to internal reflux due to heat dissipation. It took 1 hour and 40 minutes from the first drop, and the amount of distillation became 40 ml (equivalent to Experimental Example 3-1). Here, the first fraction sample was collected. The temperature at this point was 118 ° C. When 40 ml was further distilled off (132 ° C .: total time 3 hours 47 minutes), the pressure was once returned to normal pressure, and a second fraction sample and 2.55 g of the can residue sample were collected. Further, the pressure was reduced again to 380 mmHg, and the reaction was completed when 2.97 g was distilled off. The internal volume of the flask was 54.47 g from the tare of the flask and the subtraction before and after the experiment. Crystals did not precipitate throughout the time of simple distillation.

  The first distillate composition is 100% acetic acid, the second distillate composition is 97% acetic acid (both fractions are almost 100% within the error range), and the composition of the can residue when the second fraction is sampled Of acetic acid was 49%, acetamide was 7.3%, oxalic acid was 18%, oxalic acid monoamide was 16%, and ammonia was 6.1%.

Example 4
In the following, special grade reagents manufactured by Wako Pure Chemical Industries, Ltd. were used for ammonium acetate, sodium acetate, and potassium acetate.

Experimental example 4-1
Ammonium acetate 15.22 g (0.198 mol), ion-exchanged water 20.01 g, Wako Pure Chemical Industries 28% ammonia water 5.20 g (0.086 mol as ammonia) was placed in a 200 ml flask, and this was placed in a simple distillation apparatus to 150 mmHg. The pressure was reduced and the oil bath was heated to 90 ° C. Distillation began when the liquid temperature in the flask reached 62 ° C. When the liquid temperature in the flask reached 75 ° C, the distillate was sampled. The amount was 15.79 g. Thereafter, the pressure was reduced to 100 mmHg to obtain 3.35 g of a distillate and 18.54 g of a can residue.

  The acetic acid contained in the first distillate was 0.34 wt%, the acetic acid contained in the second distillate was 0.72 wt%, and the acetic acid contained in the can residue was 62.4 wt% (0.193 mol). The ammonia in the can residue was 13.9 wt% (0.152 mol).

  From this result, it was proved that acetic acid exists as ammonium acetate and hardly vaporizes below the melting point (114 ° C.) of ammonium acetate, so that aqueous ammonia can be separated.

Experimental example 4-2
Experiments were performed using the experimental apparatus shown in FIG. As the distillation column 10, a 20-stage Oldershaw distillation column was used. In order to improve the liquid holding and the distillation effect, an inert gas is circulated from the cylinder 11 to the distillation column 10 through the bottom flask 13 immersed in the oil bath 12, and the non-condensable gas is gas purged through the condenser 14. Exhaust from line 15 into the draft.

The raw material charge was 249.9 g of ammonium acetate, 150.0 g of sodium acetate, and 250.0 g of ion-exchanged water. The raw material tank 16 with a heat retaining device was preheated to 90 ° C.
The volume of the flask 13 at the bottom of the column was 500 ml, and 30.06 g of ammonium acetate, 20.27 g of sodium acetate and 70.16 g of acetic acid were charged for start-up.

  When the internal temperature of the bottom flask 13 reached 120 ° C., the raw material in the raw material tank 16 was supplied from the top of the distillation column 10 through the preheater (preheater) 17 at a flow rate of 165 cc / hr. At this time, the temperature of the preheater 17 was 110 ° C.

  When the operation was started for 51 minutes after starting the raw material supply, 63.6 g of a distillate and 120.5 g of a can residue in the flask were taken out as the first extraction. Furthermore, 43.9 g of the distillate and 71.1 g of the can residue in the flask were taken out as the second extraction after 37 minutes of operation.

  Hereinafter, it was assumed that the steady state.

  Furthermore, when it was operated for 36 minutes, 44.5 g of a distillate and 60.3 g of a can residue in the flask were taken out as a first analysis sample. Furthermore, when it was operated for 36 minutes, 46.3 g of a distillate and 74.5 g of a can residue in the flask were taken out as a second analysis sample.

  The composition of each analytical sample was as shown in Table 35.

  As is clear from Table 35, there is no great difference in the composition of the first and second analysis samples, and it can be considered that the composition was almost in a steady state. Assuming that the operation is almost in a steady state, comparing the composition of the feedstock and the composition of the second analysis sample, the mass balance is as shown in Table 36 below. The feed 165 cc / hr was converted to a unit g / hr using a raw material specific gravity of 1.14.

  The amount of acetamidated ammonia was obtained by calculation as follows. That is, as shown in Table 35, acetamide in the can residual liquid was 8.1 wt%, and this was converted to ammonia in terms of moles, and 1.7 g was determined by converting it in weight.

  As is apparent from Table 36, the total analysis value of ammonia is 8.5 g / hr (= 3.8 + 3.0 + 1.7), and the supply amount is 9.7 g / hr. But the error is outstanding. This is mainly because part of the ammonia is lost in the draft together with the non-condensable gas, and it is volatilized when the sample is collected and the analytical standard solution is prepared.

  Ammonia supplied as ammonium acetate was found to be 51.3% distilled off or separated as non-condensable gas, assuming that the residual ammonium acetate and acetamide in the can residue liquid (column bottom extraction) could not be decomposed and distilled. At the same time, it is clear that acetic acid having a low water content and ammonia water not containing acetic acid, which are not normally considered, could be obtained by a distillation column having only 20 stages.

Experimental Example 4-3
Experiments were conducted using the experimental apparatus shown in FIG. 6 in the same manner as in Experimental Example 4-2, except that ammonium acetate, sodium acetate, and potassium acetate were used as raw materials, and the raw material charge amount and operating conditions were changed. went.

  The raw material was charged with 250 g of ammonium acetate, 150.0 g of potassium acetate, and 250.0 g of ion-exchanged water, and preheated to 90 ° C. The flask at the bottom was charged with 30.04 g ammonium acetate, 20.28 g potassium acetate and 70.27 g acetic acid for start-up.

  When the internal temperature of the bottom flask reached 120 ° C., the raw material was supplied from the top of the tower at a flow rate of 150 cc / hr. At this time, the temperature of the preheater was 110 ° C.

  When the feed was started and the operation was continued for 59 minutes, 65.7 g of the distillate and 133.4 g of the residual liquid in the flask were taken out as the first extraction. Further, after the operation for 40 minutes, as a second extraction, 43.5 g of a distillate and 76.2 g of a can residue in the flask were taken out.

  Hereinafter, it was assumed that the steady state.

  Furthermore, when it was operated for 40 minutes, 42.6 g of a distillate and 68.5 g of a can residue in the flask were taken out as a first analysis sample. Furthermore, when it was operated for 40 minutes, 43.5 g of a distillate and 68.1 g of a flask residual liquid were taken out as a second analysis sample.

  The composition of each analytical sample was as shown in Table 37.

  As apparent from Table 37, there is no great difference in the composition of the first and second analysis samples, and it can be considered that the composition was almost in a steady state. Assuming that the operation is in a substantially steady state, the mass balance is as shown in Table 38 below when the composition of the feedstock and the composition of the second analysis sample are compared. The feedstock 150 cc / hr was converted to a unit g / hr using a raw material specific gravity of 1.14.

  The amount of acetamidated ammonia was obtained by calculation as follows. That is, as shown in Table 37, the acetamide in the can residual liquid was 5.0 wt%, and this was converted into ammonia by the number of moles, and 1.0 g was obtained by converting it into weight.

  As is apparent from Table 38, the total analysis value of ammonia was 6.2 g / hr (= 3.8 + 1.4 + 1.0), and a large error occurred with respect to the supply amount of 9.7 g / hr. This is because, as in Experimental Example 4-2, a part of ammonia is mainly lost into the draft together with the non-condensable gas and is volatilized at the time of sample collection and preparation of the analytical standard solution. The reason for the large error of potassium is not clear.

  Assuming that ammonia supplied as ammonium acetate could not decompose and distill off the remaining ammonium acetate and acetamide in the can residual liquid (withdrawn from the bottom of the tower), 75.4% would be distilled off or separated as a non-condensable gas. At the same time, it is apparent that acetic acid having a low water content and ammonia water containing no acetic acid, which are not normally considered, could be obtained by using only a 20-stage distillation column.

Experimental Example 4-4
An experiment was performed using the experimental apparatus shown in FIG. 6 in the same manner as in Experimental Example 4-2, except that ammonium acetate and potassium acetate were used as the raw material, and the raw material charge and operating conditions were changed.

  The raw materials were charged with 250.1 g of ammonium acetate, 150.1 g of potassium acetate and 160.0 g of ion-exchanged water and preheated to 90 ° C. The flask at the bottom was charged with 30.1 g of ammonium acetate, 20.1 g of potassium acetate, and 70.0 g of acetic acid for start-up.

  When the internal temperature of the bottom flask reached 138.4 ° C., the raw material was supplied from the top of the tower at a flow rate of 174 cc / hr. At this time, the temperature of the preheater was 109.5 ° C.

  After starting the supply of raw materials and operating for 22 minutes, 19.1 g of a distillate and 95.0 g of a can residue in the flask were taken out as the first extraction. Furthermore, 32.0 g of distillate and 90.4 g of can residue in the flask were taken out as a second extraction after 37 minutes of operation.

  Hereinafter, it was assumed that the steady state.

  Furthermore, after operating for 35 minutes, 22.8 g of a distillate and 74.6 g of a can residue in the flask were taken out as a first analysis sample. Furthermore, when it was operated for 34 minutes, 28.4 g of a distillate and 77.7 g of a can residue in the flask were taken out as a second analysis sample.

  The composition of each analytical sample was as shown in Table 39.

  As apparent from Table 39, there is no great difference in the composition of the first and second analysis samples, and it can be considered that the composition was almost in a steady state. Assuming that the operation is in a substantially steady state, the mass balance is as shown in Table 40 below when the composition of the feedstock and the composition of the second analysis sample are compared. The feed material 174 cc / hr was converted to a unit g / hr using a raw material specific gravity of 1.18.

  The amount of acetamidated ammonia was obtained by calculation as follows. That is, as shown in Table 39, acetamide in the can residual liquid was 2.2 wt%, which was converted to ammonia in terms of moles, and 0.72 g was calculated by converting it to weight.

  As is apparent from Table 40, the total analysis value of ammonia was 4.5 g / hr (= 2.1 + 1.7 + 0.7), and a large error occurred with respect to the supply amount of 11.4 g / hr. This is because, as in Experimental Example 4-2, a part of ammonia is mainly lost into the draft together with the non-condensable gas and is volatilized at the time of sample collection and preparation of the analytical standard solution. The reason for the large error of potassium is not clear.

  Ammonia supplied as ammonium acetate was 78.7% distilled off or separated as non-condensable gas, assuming that the remaining ammonium acetate and acetamide in the can residue liquid (column bottom extraction) could not be decomposed and distilled. At the same time, it is clear that acetic acid having a low water content and ammonia water not containing acetic acid, which are not normally thought of, can be obtained by using only 20 distillation columns.

Experimental Example 4-5
An experiment was performed using the experimental apparatus shown in FIG. 6 in the same manner as in Experimental Example 4-2, except that ammonium acetate and potassium acetate were used as the raw material, and the raw material charge and operating conditions were changed.

  The raw materials were charged with 250.1 g of ammonium acetate, 150.1 g of potassium acetate and 150.0 g of ion-exchanged water, and preheated to 90 ° C. The flask at the bottom was charged with 30.1 g ammonium acetate, 20.0 g potassium acetate, and 70.1 g acetic acid for start-up.

  21 minutes after starting the temperature increase, the raw material was fed from the top of the column at a flow rate of 160.0 cc / hr. After 11 minutes, an initial distillation was obtained. At that time, the internal temperature of the bottom flask was 137.2 ° C., and the temperature of the preheater was 108.5 ° C.

  After starting the raw material supply and operating for 19 minutes, as the first extraction, 10.7 g of a distillate and 102.8 g of the flask residual liquid were taken out. Furthermore, 31.1 g of the distillate and 79.8 g of the residue in the flask were taken out as a second extraction after 30 minutes of operation.

  Hereinafter, it was assumed that the steady state.

  Furthermore, 31.8 g of the distillate and 76.9 g of the residue in the flask were taken out as the first analysis sample after 37 minutes of operation. Furthermore, when it was operated for 38 minutes, 31.1 g of a distillate and 79.4 g of a residue in the flask were taken out as a second analysis sample.

  The composition of each analytical sample was as shown in Table 41.

  As is clear from Table 41, there is no great difference in the composition of the first and second analysis samples, and it can be considered that they were almost in a steady state. Assuming that the operation is in a substantially steady state, the mass balance is as shown in Table 42 below when the composition of the feedstock and the composition of the second analysis sample are compared. The feedstock 160.0 cc / hr was converted to the unit g / hr using the raw material specific gravity 1.20.

  The amount of acetamidated ammonia was obtained by calculation as follows. That is, as shown in Table 41, the acetamide in the can residual liquid was 2.2 wt%, and this was converted into ammonia in terms of moles, and 1.05 g was calculated by converting it into weight.

  As is clear from Table 42, the total analysis value of ammonia was 5.6 g / hr (= 2.6 + 2.1 + 1.1), which was a large error with respect to the supply amount of 11.7 g / hr. This is because, as in Experimental Example 4-2, a part of ammonia is mainly lost into the draft together with the non-condensable gas and is volatilized at the time of sample collection and preparation of the analytical standard solution. The reason for the large error of potassium is not clear.

  Ammonia supplied as ammonium acetate was 72.8% distilled off or separated as non-condensable gas, assuming that the residual ammonium acetate and acetamide in the can residue liquid (column bottom extraction) could not be decomposed and distilled. At the same time, it is clear that acetic acid having a low water content and ammonia water not containing acetic acid, which are not normally thought of, can be obtained by using only 20 distillation columns.

Comparative Experimental Example 4-1
Ammonium acetate 15.23 g (0.198 mol), sodium acetate 15.21 g (0.185 mol), potassium acetate 5.02 g (0.051 mol), and ion-exchanged water 50.01 g were placed in a 200 ml flask, and this was placed in a simple distillation apparatus. This was attached to an oil bath heated to 180 ° C. Distillation started when the liquid temperature in the flask reached 108 ° C. When the liquid temperature in the flask reached 150 ° C., the heating was stopped, and the distillate and can residue were sampled. The distillation time was 63 minutes. The amount of the distillate was 53.18 g, and the amount of the can residue was 30.28 g. Since it precipitated in about 30 minutes from the first distillation, the pH could not be measured.

  The acetic acid contained in the distillate was 5.47 wt% (0.049 mol), and ammonia was 2.98 wt% (0.093 mol). The acetic acid contained in the can residue was 79.32 wt% (0.400 mol) and ammonia was 0.64 wt%.

  Excluding acetic acid (0.236 mol: from the charged amount) present as an alkali metal salt, it was 0.164 mol, and 24.7% of acetic acid ammonium (0.198 mol: from the charged amount) to be decomposed was distilled off. That's right. Ammonia was exhausted without condensing, so it was not balanced.

Comparative Experimental Example 4-2
Ammonium acetate (15.22 g, 0.198 mol), potassium acetate (10.00 g, 0.102 mol), and ion-exchanged water (50.05 g) were placed in a 200 ml flask and placed in a simple distillation apparatus. This was attached to an oil bath heated to 180 ° C. Distillation began when the liquid temperature in the flask reached 106 ° C. When the liquid temperature in the flask reached 150 ° C., the heating was stopped, and the distillate and can residue were sampled. The distillation time was 51 minutes. The amount of the distillate was 53.19 g, and the amount of the can residue was 20.26 g. Since it precipitated immediately after sampling, the pH could not be measured.

  The acetic acid contained in the distillate was 5.05 wt% (0.045 mol), and ammonia was 3.22 wt% (0.101 mol). Acetic acid contained in the can residue was 76.51 wt% (0.258 mol), and ammonia was not detected.

  Excluding acetic acid (0.102 mol: from the charged amount) present as an alkali metal salt, it was 0.156 mol, and 22.7% of acetic acid to be decomposed originally (0.198 mol: from the charged amount) was distilled off. That's right. Ammonia was exhausted without condensing, so it was not balanced.

Comparative Experimental Example 4-3
Ammonium acetate 15.20 g (0.197 mol), sodium acetate 5.00 g (0.061 mol), potassium acetate 15.00 g (0.153 mol), and ion-exchanged water 50.04 g were placed in a 200 ml flask, and this was placed in a simple distillation apparatus. This was attached to an oil bath heated to 180 ° C. Distillation started when the liquid temperature in the flask reached 108 ° C. When the liquid temperature in the flask reached 150 ° C., the heating was stopped, and the distillate and can residue were sampled. The distillation time was 41 minutes. The amount of the distillate was 52.32 g, and the amount of the can residue was 31.32 g. Since it precipitated immediately after sampling, the pH could not be measured.

  The acetic acid contained in the distillate was 5.72 wt% (0.050 mol), and ammonia was 3.68 wt% (0.113 mol). The acetic acid contained in the can residue was 72.21 wt% (0.377 mol), and ammonia was not detected.

  Excluding acetic acid (0.214 mol: from the charged amount) present as an alkali metal salt, it was 0.163 mol, and 25.4% of acetic acid to be decomposed originally (0.197 mol: from the charged amount) was distilled off. That's right. Ammonia was exhausted without condensing, so it was not balanced.

Comparative Experimental Example 4-4
Ammonium acetate (15.20 g, 0.197 mol), potassium acetate (10.02 g, 0.102 mol), and ion-exchanged water (15.27 g) were placed in a 200 ml flask and placed in a simple distillation apparatus. This was attached to an oil bath heated to 180 ° C. Distillation started when the liquid temperature in the flask reached 116 ° C. When the liquid temperature in the flask reached 150 ° C., the heating was stopped, and the distillate and can residue were sampled. The distillation time was 23 minutes. The amount of the distillate was 16.65 g, and the amount of the can residue was 21.76 g. Since it precipitated immediately after sampling, the pH could not be measured.

  The acetic acid contained in the distillate was 8.43 wt% (0.023 mol), and ammonia was 7.00 wt% (0.069 mol). The acetic acid contained in the can residue was 75.62 wt% (0.274 mol), and ammonia was 2.13 wt% (0.027 mol).

  Excluding acetic acid (0.102 mol: from the charged amount) present as an alkali metal salt, it was 0.172 mol, and 11.7% of acetic acid to be decomposed originally (0.197 mol: from the charged amount) was distilled off. That's right. Ammonia was exhausted without condensing, so it was not balanced.

Comparative Experimental Example 4-5
Ammonium acetate (15.20 g, 0.197 mol), sodium acetate (10.01 g, 0.122 mol), and ion-exchanged water (15.19 g) were placed in a 200 ml flask and placed in a simple distillation apparatus. This was attached to an oil bath heated to 180 ° C. Distillation started when the liquid temperature in the flask reached 116 ° C. When the liquid temperature in the flask reached 135 ° C., solid precipitation was observed. When the liquid temperature in the flask reached 150 ° C., the heating was stopped, and the distillate and can residue were sampled. The distillation time was 23 minutes. The amount of the distillate was 17.17 g and the amount of the can residue was 21.25 g. Since it precipitated, pH was not able to be measured.

  The acetic acid contained in the distillate was 11.33 wt% (0.032 mol), and ammonia was 6.02 wt% (0.061 mol). The acetic acid contained in the can residue was 83.97 wt% (0.297 mol) and ammonia was 2.13 wt% (0.027 mol).

  Excluding acetic acid (0.122 mol: from the charged amount) present as an alkali metal salt, it was 0.175 mol, and 16.2% of acetic acid to be decomposed originally (0.197 mol: from the charged amount) was distilled off. That's right. Ammonia was exhausted without condensing, so it was not balanced.

1 is a schematic system diagram showing the configuration of an apparatus suitable for carrying out the method for decomposing an ammonium salt of acid B of the present invention. It is a typical systematic diagram which shows the structure of another apparatus suitable for implementation of the decomposition | disassembly method of the ammonium salt of the acid B of this invention. It is a typical systematic diagram which shows the structure of another apparatus suitable for implementation of the decomposition | disassembly method of the ammonium salt of the acid B of this invention. It is a typical systematic diagram which shows the structure of another apparatus suitable for implementation of the decomposition | disassembly method of the ammonium salt of the acid B of this invention. It is a typical systematic diagram which shows the structure of another apparatus suitable for implementation of the decomposition | disassembly method of the ammonium salt of the acid B of this invention. It is a block diagram of the apparatus used in Experimental example 4-2 to 4-6.

Explanation of symbols

1,1A, 1B Distillation tower 2 Evaporation tank 3 Acetamide decomposition tank 4 Thin film evaporator 5 Flash drum 10 Distillation tower 12 Oil bath 13 Flask 16 Raw material tank 17 Preheater

Claims (32)

A method for producing an organic acid A, comprising separating an organic acid A as a solid from an ammonium salt of the organic acid A by reaction crystallization using an acid B satisfying the following formula (1).
pKa (A) ≦ pKa (B) (1)
(However, pKa (A) and pKa (B) represent the ionization index of organic acid A and acid B, respectively, and when they have a plurality of values, represent the smallest pKa of them.)   The method for producing an organic acid according to claim 1, wherein the acid B is volatile.   The method for producing an organic acid according to claim 1 or 2, wherein the organic acid A is an organic acid having a melting point of 120 ° C or higher.   The method for producing an organic acid according to any one of claims 1 to 3, wherein the organic acid A is a dicarboxylic acid or tricarboxylic acid having 4 to 12 carbon atoms, or an amino acid.   The method for producing an organic acid according to any one of claims 1 to 4, wherein the acid B is a monocarboxylic acid.   The method for producing an organic acid according to any one of claims 1 to 4, wherein the acid B is acetic acid or propionic acid.   The method for producing an organic acid according to any one of claims 1 to 6, wherein the reaction crystallization is one-stage or multistage, and has at least one stage having a pH of 2.1 to 6.5.   An ammonium salt of organic acid A is obtained through a microbial conversion step in which a carbon source is converted by a microorganism in the presence of one or more neutralizing agents selected from the group consisting of ammonia, ammonium carbonate, and urea. The method for producing an organic acid according to claim 1, wherein the organic acid is produced.   The organic acid A ammonium salt is a carbon source selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, and alkaline earth metal carbonates. Alternatively, a reaction liquid containing an alkali metal and / or alkaline earth metal salt of the organic acid A is obtained through a microorganism conversion step in which the microorganism is converted in the presence of two or more neutralizing agents, and the alkali of the organic acid A is obtained. Precipitation of alkali metal and / or alkaline earth metal carbonates by adding ammonia and carbon dioxide and / or ammonium carbonate to a reaction solution containing metal and / or alkaline earth metal salt to perform reaction crystallization. The method for producing an organic acid according to claim 1, wherein the precipitated carbonate is separated and obtained as an aqueous ammonium salt solution of organic acid A. .   The method for producing an organic acid according to claim 8 or 9, further comprising a concentration step of concentrating the reaction solution obtained in the microorganism conversion step, and subjecting the concentrate obtained in the concentration step to reaction crystallization.   The method for producing an organic acid according to any one of claims 1 to 7, wherein the ammonium salt of the organic acid A is obtained by a chemical process.   The organic acid A precipitated by the reaction crystallization is separated, the ammonium salt of the acid B in the separated crystallization mother liquor is decomposed by a decomposition step to obtain an acid B, and the obtained acid B is used as a solvent for the reaction crystallization. The method for producing an organic acid according to any one of claims 1 to 11, wherein the organic acid is circulated and reused.   The organic acid A deposited by the reaction crystallization is separated, and the acid B is vaporized from the separated crystallization mother liquor and concentrated. Then, the acid B and its ammonium salt are decomposed and vaporized to obtain the organic acid A and its ammonium salt. The method for producing an organic acid according to claim 12 to be recovered.   The method for producing an organic acid according to claim 13, wherein the acid B is vaporized at a temperature equal to or lower than the melting point of the ammonium salt.   The method for producing an organic acid according to claim 13 or 14, wherein the decomposition and vaporization of the acid B and its ammonium salt are carried out by heating the ammonium salt of the acid B under a reduced pressure of 0.001 mmHg to 200 mmHg.   In the decomposition step, a liquid containing an ammonium salt of acid B, an alkali metal salt of acid B and / or an alkaline earth metal salt, and water is heated to extract a gas of the basic aqueous solution, and extracted from the heating step. 16. The method according to claim 12, further comprising a step of gas-liquid separation, gas-solid separation, or gas-liquid solid separation at a temperature below the melting point of the acid B ammonium salt, directly or after condensing the basic aqueous solution. A method for producing an organic acid according to claim 1.   In the decomposition step, a liquid containing an ammonium salt of acid B and an alkali metal salt of acid B and / or an alkaline earth metal and water is supplied to a distillation column having two or more stages as the actual number of stages, and from the top of the distillation tower The method for producing an organic acid according to any one of claims 12 to 15, further comprising a heating step of extracting a gas of the basic aqueous solution.   In the heating step, a liquid containing an ammonium salt of acid B and an alkali metal salt of acid B and / or an alkaline earth metal and water is used in a distillation column of two or more stages as the actual number of stages, and below the melting point of the ammonia salt of acid B The manufacturing method of the organic acid of Claim 17 supplied to the site | part which becomes.   The alkali metal and / or alkaline earth metal forming the alkali metal salt and / or alkaline earth metal salt of acid B is one or more selected from the group consisting of Na, K, Ca, and Mg The method for producing an organic acid according to any one of claims 16 to 18.   20. The separation and recovery step of separating and recovering the acid B from a liquid after extracting the gas of the basic aqueous solution in the heating step at 125 ° C. or higher under reduced pressure or normal pressure. A method for producing an organic acid.   21. The method for producing an organic acid according to claim 20, wherein the residual liquid after the separation and recovery step is mixed with a system containing water, the amide compound by-produced in the heating step and the separation and recovery step is hydrolyzed, and then circulated to the heating step. .   A reaction in which an ammonium salt of organic acid A is obtained as a reaction solution containing an ammonium salt of organic acid A through a microorganism conversion step in which ammonia is used as a neutralizing agent and converted by microorganisms. The organic acid A deposited by crystallization is separated, the ammonium salt of acid B in the crystallization mother liquor after separation is decomposed to obtain ammonia, and the ammonia is used as a neutralizing agent in the microbial conversion step. The method for producing an organic acid according to any one of 10 and 12 to 21.   The organic acid A ammonium salt is a carbon source selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, and alkaline earth metal carbonates. Alternatively, in the presence of two or more kinds of neutralizing agents, a reaction solution containing an alkali metal and / or alkaline earth metal salt of the organic acid A is obtained through a microorganism conversion step in which the microorganism is converted, and the alkali metal of the organic acid A is obtained. And / or by adding ammonia and carbon dioxide and / or ammonium carbonate to the reaction solution containing the alkaline earth metal salt and performing reaction crystallization to precipitate the alkali metal and / or alkaline earth metal carbonate. (Solvay method reaction crystallization step) The carbonate was separated and obtained as an aqueous ammonium salt solution of organic acid A, and the organic acid A deposited by reaction crystallization performed by adding acid B was separated. The ammonium salt of acid B in the crystallization mother liquor after separation is decomposed to obtain ammonia, and the ammonia is used as an ammonia source in the Solvay method reaction crystallization step. The manufacturing method of the organic acid of description.   Reaction crystallization is multistage, and in the second and subsequent stages of reaction crystallization, the crystallization mother liquor after separation of the precipitated organic acid A is used as the ammonium of acid B directly or by evaporation of the reaction crystallization solvent containing acid B. 24. After concentrating the salt or separating the organic acid A or its salt dissolved in the mother liquor, the acid B and its ammonium salt are circulated to the crystallization tank for the reaction crystallization in the preceding stage. The manufacturing method of the organic acid in any one of.   In the method of decomposing acid B ammonium salt into acid B and ammonia to separate and recover acid B and ammonia, acid B ammonium salt and acid B alkali metal salt and / or alkaline earth metal salt and water A step of heating the liquid containing the aqueous solution to extract the gas of the basic aqueous solution, and the direct or condensation of the basic aqueous solution extracted in the heating step, followed by gas-liquid separation at a temperature below the melting point of the ammonium salt of the acid B A method for decomposing an ammonium salt, comprising gas-solid separation or gas-liquid solid separation.   In the method of decomposing acid B ammonium salt into acid B and ammonia to separate and recover acid B and ammonia, acid B ammonium salt and acid B alkali metal salt and / or alkaline earth metal salt and water And a heating step of extracting the gas of the basic aqueous solution from the top of the distillation column. A method for decomposing ammonium salts characterized by the above.   The alkali metal and / or alkaline earth metal constituting the alkali metal salt and / or alkaline earth metal salt of acid B is one or more selected from the group consisting of Na, K, Ca, and Mg. The method for decomposing an ammonium salt according to claim 25 or 26.   28. The method for decomposing an ammonium salt according to claim 25, wherein the acid B is one or more selected from the group consisting of formic acid, acetic acid, propionic acid, and butyric acid.   29. A process for separating and recovering acid B, wherein the acid B is separated and recovered by a separation process at 125 ° C. or higher under reduced pressure or normal pressure after extracting the gas of the basic aqueous solution in the heating process. The method for decomposing an ammonium salt according to any one of the above.   The method for decomposing an ammonium salt according to claim 29, wherein the residual liquid after the separation and recovery step is mixed with a system containing water, and the amide compound by-produced in the heating step and the separation and recovery step is hydrolyzed and then circulated to the heating step. .   The organic acid A manufactured with the manufacturing method of the organic acid in any one of Claim 1 thru | or 24.   A polymer using, as a raw material, an organic acid A produced by the method for producing an organic acid according to any one of claims 1 to 24.

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