JP5090989B2 - Process for producing α-acyloxyacrylic acid and / or ester thereof - Google Patents

Description

  The present invention relates to a method for producing α-acyloxyacrylic acid and / or its ester.

  In recent years, biorefinery technology has attracted attention as a technology for producing energy and chemicals from biomass, which is a renewable resource. Biorefinery produces energy and chemicals by producing various gases such as synthesis gas, saccharides such as glucose and aromatic compounds such as lignin by gasification, saccharification and extraction of various biomass. It is to try. Therefore, the biorefinery technology is positioned as a very important technology for realizing a paradigm shift from a mass production dependent on conventional oil refinery (petroleum refining) and a mass consumption society to a sustainable society.

  As for polymer materials, carbon-neutral materials such as bio-based plastics manufactured from plant-derived materials are expected to increase in demand in the future. Among them, polylactic acid (hereinafter referred to as PLA) is a promising material that is being used in the industrial world as a bio-based plastic. PLA is produced by the lactide method using lactic acid as a raw material. Lactic acid, which is a raw material of PLA, is produced mainly by fermentation of glucose obtained by saccharification of starch and cellulose. Hydrolysis of cyanohydrin produced by the action of hydrocyanic acid on acetaldehyde, terminal in 1,2-propanediol It can also be obtained by a chemical synthesis method such as oxidation of an alcohol group to a carboxyl group.

  At present, lactic acid is mainly used as a raw material for PLA. However, if the PLA market further expands in the future, the production amount of lactic acid will increase accordingly. It can also be expected to be a starting material.

  Until now, various attempts have been made to produce various chemicals using lactic acid and its esters as raw materials. For example, as a method for producing pyruvic acid and / or its ester, a lactic acid ester is a molecule in the presence of a tin-molybdenum complex oxide (Patent Document 1) or in the presence of a tellurium-molybdenum complex oxide (Patent Document 2). A method of oxidizing with gaseous oxygen, a method of gas phase catalytic oxidation with molecular oxygen in the presence of a composite metal oxide catalyst containing molybdenum, vanadium, tellurium and / or antimony (Patent Document 3), lactic acid and its ester with platinum or / And a method in which palladium is oxidized with an oxygen-containing gas in the presence of a catalyst containing at least one element selected from the group consisting of lead, tin, tellurium and indium (Patent Document 4), and further, lactic acid is converted to iron phosphate And gas phase catalytic oxidation with molecular oxygen in the presence of a catalyst containing palladium and palladium (Patent Document 5).

  Alternatively, as a method for producing acrylic acid, a method in which lactic acid and ammonium lactate are subjected to gas phase catalytic conversion with aluminum phosphate (Patent Document 6), and lactic acid is subjected to supercritical conditions (Non-patent Document 1) or subcritical conditions (non-patent). The method of conversion in literature 2) can be mentioned.

  Thus, useful compounds that can be produced from lactic acid and its esters are diverse. Lactic acid is a plant-derived compound that is produced mainly from glucose obtained by saccharification of cellulose or starch, and therefore can be expected as a platform compound for producing various chemical products by biorefinery.

  The method for producing pyruvic acid and its ester from lactic acid and its ester is as described above. On the other hand, pyruvic acid is an important compound that is deeply involved in glycolysis, which is a metabolic pathway of sugar in living organisms, and its sodium salt is produced industrially by fermentation using glucose as a raw material.

  Pyruvate and its esters are also useful as intermediates in various chemical synthesis, and are used as raw materials for synthesizing amino acids such as L-tryptophan, L-cysteine, and L-tyrosine.

The inventor of the present application particularly paid attention to α-acyloxyacrylic acid represented by the formula (1) and its ester. As a method for producing α-acyloxyacrylate ester from methyl pyruvate, there is a method of acylating methyl pyruvate with acetic anhydride under heating and refluxing conditions in the presence of paratoluenesulfonic acid (Non-patent Document 3). Alternatively, there is a method of acylating with acetic anhydride by heating and stirring at 80 ° C. in the presence of pyridine (Non-patent Document 4).

In the formula (1), R ¹ is a hydrogen atom, an unsubstituted or substituted alkyl group, or an unsubstituted or substituted aryl group. The alkyl group and aryl group may have an unsaturated bond. Examples of R ¹ include a methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, 3-methylpropyl group, n-pentyl group, 2 -Methylbutyl group, 3-methylbutyl group, 4-methylbutyl group, 2,2-dimethylpentyl group, cycloheptyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n -An undecanyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a phenyl group, and a benzyl group are mentioned. R ² is a group having a skeleton derived from saturated fatty acid, unsaturated carboxylic acid, oxocarboxylic acid or aromatic carboxylic acid as the acyl group of R ² CO, and the number of carboxyl groups is not limited, and other substituents And may have an unsaturated bond in the same skeleton. Examples of the acyl group of R ² CO include acetyl, propanoyl, butanoyl, 2-methylpropanoyl, n-pentanoyl, 2-methylbutanoyl, 2,2-dimethylpropanoyl, 3- Methylbutanoyl group, n-hexanoyl group, 2-methylpentanoyl group, 3-methylpentanoyl group, 4-methylpentanoyl group, 2,2-dimethylbutanoyl group, heptanoyl group, octanoyl group, nonanoyl group, decanoyl Group, dodecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, cis-9-octadecenoyl group, cis, cis-9,12-octadecadienoyl group, 9,12,15-octadecatrie Noyl group, 6,9,12-octadecatrienoyl group, benzoyl group, 2-hydroxyben Yl group, 4-carboxybenzoyl group, 2-carboxybenzoyl group, 3-carboxybenzoyl group, 1-carboxypropanoyl group, carboxyethanoyl group, cis-1-carboxyacryloyl group, trans-1-carboxyacryloyl group, β -A phenyl acryloyl group, a crotonoyl group, an acryloyl group, a methacryloyl group is mentioned.

The obtained α-acyloxyacrylic acid and its ester are expected to be used as a monomer having a double bond, particularly as a polymer having high heat resistance, high transparency and high mechanical strength by polymerization of the ester. (Patent Document 7). Furthermore, if it is the polymer manufactured from the pyruvic acid derived from the plant manufactured from starch, cellulose, etc. and its ester, the utilization as a biobase polymer is also possible (nonpatent literature 5).
JP-A-6-56743 JP-A-6-234704 JP 2002-212139 A Japanese Patent Publication No. 61-15863 JP 2003-146935 A JP-A-61-115049 Japanese Patent Laying-Open No. 2005-255991 Journal of Organic Chemistry, 54, 4596-4602 (1989) Industrial Engineering & Chemistry Research, 32, 2608-2613 (1993) Journal of Organic Chemistry, 29, 3596-3598 (1964) Polymer International, 54, 1557-1563 (2005). Advanced Polymers One Point Vol. 5 Natural Materials Plastics, p104, edited by the Society of Polymer Science, Kyoritsu Shuppan (2006)

  The production method for α-acyloxyacrylic acid and its ester is as described in Non-Patent Documents 3 and 4. However, in this production method, severe reaction conditions such as high temperature conditions, dehydration conditions and long reaction time are required, and a wide variety of by-products are produced, so that the yield of the target product is not good. Further, since paratoluenesulfonic acid or pyridine is used as a catalyst, there is a drawback that it is difficult to recover and reuse the catalyst. Moreover, in order to polymerize this monomer into a polymer, it is necessary to increase the monomer purity by purification such as distillation or extraction. However, since the monomers obtained by the production methods in Non-Patent Documents 3 and 4 contain a large amount of impurities, a large-scale and complicated purification process is necessary, and the cost of the process is unavoidable. There is a need for a process for producing α-acyloxyacrylic acid and its esters.

  Accordingly, an object of the present invention is to provide a method for producing α-acyloxyacrylic acid and / or its ester with high efficiency and low cost.

  The present invention is a process for producing α-acyloxyacrylic acid and / or α-acyloxyacrylic acid ester by reacting pyruvic acid and / or pyruvate with an acylating agent in the presence of a strongly acidic cation exchange resin. .

  According to the present invention, α-acyloxyacrylic acid and / or an ester thereof can be produced with higher efficiency and lower cost than conventional methods.

In the present invention, α-acyloxyacrylic acid and / or α-acyloxyacrylic acid ester is produced by reacting pyruvic acid and / or pyruvic acid ester with an acylating agent in the presence of a strongly acidic cation exchange resin. . Strongly acidic cation exchange resins are easy to use as heterogeneous catalysts and are industrially useful. Examples of the strongly acidic cation exchange resin include amberlite, amber list, diamond ion (all are trade names). The ion exchange capacity, the type of the base resin, the degree of crosslinking of the resin, and the like vary depending on the product or grade, but can be selected as appropriate. The cation bonded to the sulfonic acid group is preferably a proton (H ⁺ ), but other cations such as Na ⁺ , Ca ²⁺ , Mg ²⁺ , K ⁺ , NH ₄ ⁺ , Cu ²⁺ , and Zn ²⁺ are ^replaced with H ^+. Resins converted into can also be used.

  Α-Acyloxyacrylic acid is produced by an acylation reaction of pyruvic acid. Moreover, (alpha) -acyloxyacrylic acid ester is manufactured by acylation reaction of pyruvic acid ester. There is no restriction | limiting in particular in the kind of ester group in pyruvic acid ester and (alpha) -acyloxyacrylic acid ester, It can select suitably from an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and those substituted products. For example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, 3-methylpropyl group, n-pentyl group, 2-methylbutyl group, 3 -Methylbutyl group, 4-methylbutyl group, 2,2-dimethylpentyl group, cycloheptyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-undecanyl group, hydroxy Examples include an ethyl group, a hydroxypropyl group, a hydroxybutyl group, a phenyl group, and a benzyl group.

  Examples of the acylating agent include carboxylic acid, acid anhydride, and acid chloride, and acid anhydride is preferable. Examples of acid anhydrides such as aliphatic carboxylic acids, aromatic carboxylic acids, unsaturated carboxylic acids, monocarboxylic acids, dicarboxylic acids include acetic acid, propionic acid, butanoic acid (butyric acid), isobutyric acid, pentanoic acid (n-yoshi Herbic acid), isovaleric acid, pivalic acid, hydroangelic acid, n-hexanoic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4-methylpentanoic acid, 2,2-dimethylbutanoic acid, heptanoic acid, octanoic acid , Nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, linoleic acid, (9,12,15) -linolenic acid, (6,9,12) -linolenic acid, benzoic acid, Salicylic acid, terephthalic acid, o-phthalic acid, m-phthalic acid, succinic acid, malonic acid, maleic acid, fumaric acid, cinnamic acid, crotonic acid, acrylic acid, An acid anhydride such as tacrylic acid may be mentioned. Further, it may be a mixed acid anhydride composed of two different carboxylic acids.

  The reaction may be carried out without solvent, or a solvent that can dissolve the substrate and acylating agent may be used. There are no particular restrictions on the type of solvent, but when a large amount of water is present, ester hydrolysis and acid anhydride hydrolysis are dominant, so it is preferable that the amount of water in the solvent is small.

Regarding the reaction mechanism in the present invention, Non-Patent Document 5 proposes a mechanism via keto-enol tautomerism. That is, first, an enol form is produced by proton addition to the carbonyl oxygen at the α-keto position of pyruvic acid and / or pyruvic acid ester by an acid catalyst. The resulting enol form undergoes a nucleophilic attack on the carbonyl carbon of the acylating agent, whereby α-acyloxyacrylic acid and / or α-acyloxyacrylic acid ester is generated. However, the inventor of the present application has conducted a detailed study on the reaction mechanism. When carboxylic acid anhydride is used as the acylating agent, α-acyloxyacrylic acid and 2,4-diacyloxy compound are used. It was found that α-acyloxyacrylic acid ester was produced. By attacking pyruvic acid and / or pyruvic acid ester with a carboxylic acid anhydride as an acylating agent, 2,2-diacyloxypropionic acid and / or its ester represented by the formula (2) is generated. Furthermore, one molecule of carboxylic acid is eliminated from the 2,2-diacyloxypropionic acid and / or its ester to produce α-acyloxyacrylic acid and / or α-acyloxyacrylic acid ester. R ² and R ³ may be the same or different. For example, R ² and R ³ are the same in an acid anhydride composed of the same carboxylic acid, but a compound in which R ² and R ³ are different is obtained in a mixed acid anhydride composed of different carboxylic acids.

In Formula (2), R ¹ is a hydrogen atom, an unsubstituted or substituted alkyl group, or an unsubstituted or substituted aryl group. The alkyl group and aryl group may have an unsaturated bond. Examples of R ¹ include a methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, 3-methylpropyl group, n-pentyl group, 2 -Methylbutyl group, 3-methylbutyl group, 4-methylbutyl group, 2,2-dimethylpentyl group, cycloheptyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n -An undecanyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a phenyl group, and a benzyl group are mentioned. R ² and R ³ are groups having a skeleton derived from saturated fatty acid, unsaturated carboxylic acid, oxocarboxylic acid or aromatic carboxylic acid as the acyl groups of R ² CO and R ³ CO, and are limited to the number of carboxyl groups There may be other substituents and unsaturated bonds in the same skeleton. Examples of the acyl group of R ² CO and R ³ CO include an acetyl group, a propanoyl group, a butanoyl group, a 2-methylpropanoyl group, an n-pentanoyl group, a 2-methylbutanoyl group, and 2,2-dimethylpropanoyl. Group, 3-methylbutanoyl group, n-hexanoyl group, 2-methylpentanoyl group, 3-methylpentanoyl group, 4-methylpentanoyl group, 2,2-dimethylbutanoyl group, heptanoyl group, octanoyl group, Nonanoyl group, decanoyl group, dodecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, cis-9-octadecenoyl group, cis, cis-9,12-octadecadienoyl group, 9,12,15 -Octadecatrienoyl group, 6,9,12-octadecatrienoyl group, benzoyl group, 2- Hydroxybenzoyl group, 4-carboxybenzoyl group, 2-carboxybenzoyl group, 3-carboxybenzoyl group, 1-carboxypropanoyl group, carboxyethanoyl group, cis-1-carboxyacryloyl group, trans-1-carboxyacryloyl group, A β-phenylacryloyl group, a crotonoyl group, an acryloyl group, and a methacryloyl group can be mentioned.

  The present invention is carried out in a heterogeneous reaction, and the reaction in the liquid phase is more general.

  There is no restriction | limiting in the density | concentration of a raw material, The quantity from which a desired reaction rate is obtained can be selected suitably, for example, can be selected from 0.1-80 mass%.

  The acylating agent may be used in an equivalent amount relative to the raw material, but may be used in excess of the equivalent amount relative to the raw material so that the reaction proceeds smoothly. For example, 1.0-100 equivalent can be used with respect to a raw material.

  There is no restriction | limiting also in reaction pressure, It can carry out under both normal pressure and pressurization. In the reaction under pressure, an autoclave can be used. There is no particular limitation on the type of gas introduced or present in the system.

  Although there is no restriction | limiting in reaction temperature, It is preferable to carry out on the conditions that reaction advances smoothly and an ion exchange resin does not receive thermal degradation easily. Such reaction temperature is preferably 10 ° C to 150 ° C, more preferably 40 ° C to 100 ° C. If the conversion rate of the raw materials is to be the same, the reaction time is shorter as the reaction temperature is higher, and conversely, it is longer as the reaction temperature is lower. The reaction time can be appropriately selected in consideration of the conversion rate and the reaction temperature.

  As the reaction format, either a stirring and mixing type reactor or a flow contact type reactor can be used. Either a batch type or a continuous type can be used, but the continuous type is more advantageous in consideration of productivity.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the examples.

(Analysis of raw materials and products)
Gas chromatography (GC) equipped with a flame ionization detector, a capillary column, and a split / splitless inlet was used for analysis of raw materials and products. In addition, identification of α-acyloxyacrylic acid and / or α-acyloxyacrylic acid ester, 2,2-diacyloxypropionic acid and / or its ester is performed by gas chromatography (GC / MS) equipped with a mass spectrometer. And electrospray ionization high resolution mass spectrometry (ESI-HRMS).

  When the charged raw material amount is A (mol) and the raw material amount detected from the reaction solution after the reaction evaluation is B (mol), the conversion rate C (%) of the raw material is expressed as follows.

C (%) = 100 × (A−B) / A
Moreover, when the number of moles of the product quantified by gas chromatography is D (mol), the selectivity S (%) of the product is expressed as follows.

S (%) = 100 × D / (A−B)
Further, the yield Y (%) of the product is expressed as follows.

Y (%) = 100 × D / A
[Example 1]
(Pretreatment of ion exchange resin)
Take 3.5 g of Amberlyst 15H (MP Biomedicals, Inc.), which is a strongly acidic ion exchange resin, in a 100 ml screw-ended Erlenmeyer flask, add 25 g of acetic acid (Wako Pure Chemical Industries, Ltd.), and use a magnetic stirrer. For 1 hour at room temperature.

(Reaction evaluation)
To this flask, 2.4 g of ethyl pyruvate (manufactured by Wako Pure Chemical Industries, Ltd.) and 20 g of acetic anhydride (Wako Pure Chemical Industries, Ltd.) were added and sealed, heated to 70 ° C. with a hot stirrer and stirred. Went for hours. Meanwhile, the reaction solution was collected at 15 minutes, 30 minutes, 1 hour, 2 hours and 3 hours from the start of the reaction, allowed to cool, and then subjected to product analysis. The change in the yield of ethyl α-acetoxyacrylate with respect to the reaction time is shown in FIG. Table 1 shows the conversion rate of ethyl pyruvate, the selectivity for ethyl α-acetoxyacrylate, and the yield 3 hours after the start of the reaction.

[Example 2]
Except that the reaction temperature was 90 ° C. and the reaction time was 1 hour (5 minutes, 10 minutes, 15 minutes, 30 minutes, 45 minutes, 1 hour, the reaction solution was collected and analyzed), it was the same as in Example 1. Reaction evaluation was performed. The change in the yield of ethyl α-acetoxyacrylate with respect to the reaction time is shown in FIG. Further, Table 1 shows the conversion rate of ethyl pyruvate, the selectivity for ethyl α-acetoxyacrylate, and the yield after 1 hour from the start of the reaction.

[Example 3]
Except that the reaction temperature was 50 ° C and the reaction time was 5 hours (30 minutes, 1 hour, 2 hours, 3 hours, 4 hours and 5 hours, the reaction solution was collected and analyzed), the same as in Example 1 Reaction evaluation was performed. The change in the yield of ethyl α-acetoxyacrylate with respect to the reaction time is shown in FIG. Table 1 shows the conversion rate of ethyl pyruvate, the selectivity for ethyl α-acetoxyacrylate, and the yield 5 hours after the start of the reaction.

(Purification of reaction solution)
The strongly acidic ion exchange resin was filtered from the solution after completion of the reaction. The filtrate was concentrated on a rotary evaporator to give a brown solution. This solution was washed with a saturated aqueous sodium hydrogen carbonate solution, diethyl ether was added, and the diethyl ether phase was recovered by a separatory funnel. After adding anhydrous sodium sulfate and drying overnight, diethyl ether was distilled off by a rotary evaporator to obtain a yellowish brown reaction purified solution.

(Analysis of reaction purified solution)
Identification of ethyl α-acetoxyacrylate and ethyl 2,2-diacetoxypropionate in the reaction purified solution was performed by the following procedure. That is, this reaction refinement | purification liquid was analyzed by GC-MS, and the obtained fragment pattern was shown in FIG.2 and FIG.3. In FIG. 2, a parent ion (M ⁺ ) at m / z = 158 was observed, which was in good agreement with the molecular weight of ethyl α-acetoxyacrylate. In FIG. 3, a fragment of m / z = 173 desorbed from the ethoxy group (CH ₃ CH ₂ O, m / z = 45) from the parent ion (M ⁺ , m / z = 218) is observed, and other fragments are observed. Also agreed well with the structure of ethyl 2,2-diacetoxypropionate. Furthermore, this solution was analyzed by ESI-HRMS. The ESI-HRMS spectrum measured by adding sodium iodide (NaI) is shown in FIG. 4 and FIG. Ethyl α-acetoxyacrylate (FIG. 4) is obtained as C ₇ H ₁₀ Na ₁ O ₄ ([M + Na] ⁺ ) at m / z = 181.04690, and ethyl 2,2-diacetoxypropionate (FIG. 5) is , M / z = 241.06974, was observed as C ₉ H ₁₄ Na ₁ O ₆ ([M + Na] ⁺ ).

[Comparative Example 1]
(Reaction evaluation)
0.03 g of paratoluenesulfonic acid monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) is taken into a screw test tube (manufactured by Nidec Rika Glass Co., Ltd., product number: ST-16.5S, internal volume: 10 ml), and acetic acid Dissolved in 1.2 g. After adding 0.25 g of ethyl pyruvate and 2.1 g of acetic anhydride and sealing it, it was set in a metal bath (manufactured by Koike Seimitsu Seisakusho, model: MB-1H-UII) and heated at 70 ° C. for 1 hour. During this time, the test tube was shaken by a vortex mixer for about 10 seconds every 15 minutes. Table 1 shows the conversion rate of ethyl pyruvate in 1 hour, the selectivity and the yield of ethyl α-acetoxyacrylate.

It is the relationship between reaction time and alpha-acetoxy ethyl acrylate yield. It is a mass-spectrometry result (GC-MS) of ethyl alpha-acetoxyacrylate. It is a mass spectrometry result (GC-MS) of ethyl 2,2-diacetoxyacrylate. It is a high resolution mass spectrometry result (ESI-HRMS) of ethyl α-acetoxyacrylate. It is a high resolution mass spectrometry result (ESI-HRMS) of ethyl 2,2-diacetoxyacrylate.

Claims (1)

  A process for producing α-acyloxyacrylic acid and / or α-acyloxyacrylic acid ester, wherein pyruvic acid and / or pyruvic acid ester is reacted with an acylating agent in the presence of a strongly acidic cation exchange resin.

Images