阅读说明：本技术 香兰素的制造方法 (Method for preparing vanillin ) 是由 大久保康隆 福岛祐介 金城佑 于 2019-01-24 设计创作，主要内容包括：本发明涉及香兰素的制造方法,该制造方法包括：工序(A),对包含粗香兰素和脂肪族二羧酸二烷基酯的溶液进行蒸馏,得到香兰素溶液；和工序(B),将前述香兰素溶液供于不良溶剂析晶。根据本发明涉及的香兰素的制造方法,能够在不使用特殊的装置的状态下、以工业上足够的效率制造高纯度的香兰素。(The present invention relates to a method for producing vanillin, comprising: a step (A) in which a solution containing crude vanillin and a dialkyl ester of an aliphatic dicarboxylic acid is distilled to obtain a vanillin solution; and (B) subjecting the vanillin solution to crystallization in a poor solvent. According to the method for producing vanillin of the present invention, high-purity vanillin can be produced with industrially sufficient efficiency without using a special apparatus.)

1. A method for producing vanillin, comprising:

a step (A) in which a solution containing crude vanillin and a dialkyl ester of an aliphatic dicarboxylic acid is distilled to obtain a vanillin solution; and

and (B) subjecting the vanillin solution to crystallization in a poor solvent.

2. The process for producing vanillin according to claim 1, wherein a hydrocarbon solvent is used for the poor solvent crystallization.

3. The method for producing vanillin in claim 1 or 2, wherein the dialkyl aliphatic dicarboxylate is selected from the group consisting of dibutyl maleate, dibutyl succinate, diethyl sebacate, diisobutyl adipate, and a mixture thereof.

4. The method for producing vanillin in claim 2 or 3, wherein the hydrocarbon solvent is selected from the group consisting of n-hexane, n-heptane, cyclohexane, and a mixture thereof.

5. The method for producing vanillin according to any one of claims 2 to 4, further comprising:

a step (C) of separating the aliphatic dicarboxylic acid dialkyl ester and the hydrocarbon solvent from the crystallization mother liquor in the step (B); and

and (D) reusing the aliphatic dicarboxylic acid dialkyl ester and/or the hydrocarbon solvent obtained in the step (C).

6. A composition comprising:

97.0 to 99.99 mass% of vanillin,

0.001 to 1 mass% of an aliphatic dicarboxylic acid dialkyl ester, and

0.001 to 1% by mass of a hydrocarbon solvent.

Technical Field

The present invention relates to a method for producing vanillin.

Background

Vanillin is an aroma component contained in vanilla beans and is used as a perfume in foods, cosmetics, and the like. Conventionally, as a synthetic method of vanillin, 2 methods, i.e., synthesis by a synthetic chemical method and synthesis by a biochemical method, have been known. However, in any of the methods, the produced vanillin is accompanied by nonvolatile impurities as by-products.

As a method for removing impurities contained in produced vanillin, crystallization from a water-alcohol system is known, but it is difficult to sufficiently remove substances that are hardly soluble in a solvent, such as vanillic acid (which is an oxidation product of vanillin) and dibenzanin (which is a dimer of vanillin), by the above-mentioned crystallization. Distillation purification is known as a method for efficiently removing such impurities, but vanillin has a high melting point of 81 to 83 ℃ and requires a special apparatus for handling as a liquid at a high temperature or for performing crystallization distillation. From such a viewpoint, a method of dissolving vanillin in a solvent and distilling off vanillin together with the solvent to distill vanillin as it is in a liquid state has also been proposed (for example, see patent documents 1 and 2).

Disclosure of Invention

Problems to be solved by the invention

However, the methods described in patent documents 1 to 2 require equipment for eliminating the problems caused by excessively high or excessively low solubility of vanillin in a solvent, and therefore have a problem in efficiency in industrial practical use. Thus, the prior art cannot purify vanillin by distillation with industrially sufficient efficiency without using a special apparatus.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing vanillin of high purity with industrially sufficient efficiency without using a special apparatus.

Means for solving the problems

The present inventors have conducted extensive studies and, as a result, have found that the above problems can be solved by crystallization using a poor solvent of a predetermined material, and have completed the present invention.

That is, the present invention includes the following aspects.

[1]

A process for producing vanillin, comprising:

a step (A) in which a solution containing crude vanillin and a dialkyl ester of an aliphatic dicarboxylic acid is distilled to obtain a vanillin solution; and

and (B) crystallizing the vanillin solution in a poor solvent.

[2]

The process for producing vanillin as described in [1], wherein a hydrocarbon solvent is used for the poor solvent crystallization.

[3]

The method for producing vanillin according to claim 1 or 2, wherein the aliphatic dicarboxylic acid dialkyl ester is selected from the group consisting of dibutyl maleate, dibutyl succinate, diethyl sebacate, diisobutyl adipate, and a mixture thereof.

[4]

The process for producing vanillin according to [2] or [3], wherein the hydrocarbon solvent is selected from the group consisting of n-hexane, n-heptane, cyclohexane, and a mixture thereof.

[5]

The process for producing vanillin according to any one of [2] to [4], further comprising:

a step (C) of separating the aliphatic dicarboxylic acid dialkyl ester and the hydrocarbon solvent from the crystallization mother liquor in the step (B); and

a step (D) of reusing the aliphatic dicarboxylic acid dialkyl ester and/or the hydrocarbon solvent obtained in the step (C).

[6]

A composition comprising:

97.0 to 99.99 mass% of vanillin,

0.001 to 1 mass% of an aliphatic dicarboxylic acid dialkyl ester, and

0.001 to 1% by mass of a hydrocarbon solvent.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, high-purity vanillin can be produced with industrially sufficient efficiency without using a special apparatus.

Detailed Description

Hereinafter, a mode for carrying out the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail. The present embodiment is an example for explaining the present invention, and the present invention is not limited to the following embodiments.

[ Process for producing vanillin ]

The method for producing vanillin according to the present embodiment includes: a step (A) in which a solution containing crude vanillin and a dialkyl ester of an aliphatic dicarboxylic acid is distilled to obtain a vanillin solution; and (B) subjecting the vanillin solution to crystallization in a poor solvent. As described above, the method for producing vanillin according to the present embodiment can obtain high-purity vanillin (hereinafter, also referred to as "purified vanillin") with industrially sufficient efficiency without using a special apparatus by performing the poor solvent crystallization using a predetermined material.

In the present specification, the term "purified vanillin" means a vanillin content of 97.0 mass% or more in a crystal of vanillin obtained by synthesis. The content of vanillin is preferably 99.0 mass% or more, and more preferably 99.9 mass% or more, from the viewpoint of quality in food use. From the same viewpoint, the purified vanillin is particularly preferably vanillin which meets the item of "vanillin" in the food additive official manual, the FCC standard in the united states, and more particularly, vanillin having a needle-like crystal or powder, a white to pale yellow color tone, a purity of 97.0% or more, a melting point of 81 to 83 ℃, a loss on drying of 0.5% or less, a burning residue of 0.05% or less, a heavy metal content of 10ppm or less, and an arsenic content of 4ppm or less is particularly preferable.

(Process (A))

In the step (a), a solution containing crude vanillin and a dialkyl ester of aliphatic dicarboxylic acid is prepared, and this solution is distilled to obtain a vanillin solution. By the distillation in the step (a), impurities such as dimers and trimers of vanillin contained in the crude vanillin are removed. The method of distillation in the present embodiment is not limited to the following, and since simple distillation can be employed, desired impurities can be removed without requiring special equipment. The distillation is preferably carried out under reduced pressure. The pressure at this time may be suitably set in accordance with the aliphatic dicarboxylic acid dialkyl ester to be used, and is preferably 0.03 to 1.5kPa, more preferably 0.1 to 0.5kPa, as a pressure gauge at the top of the column. The temperature during distillation may be set as appropriate according to the use of the aliphatic dicarboxylic acid dialkyl ester, and is preferably 75 to 150 ℃ in terms of the temperature at the top of the column, more preferably 100 to 125 ℃.

In the present embodiment, the crude vanillin is not particularly limited, and vanillin obtained by various known methods can be used. Specifically, crude vanillin obtained by a known synthetic chemical method, crude vanillin obtained by a known biochemical method, or extracted vanillin extracted from vanilla beans may be used. In particular, for food use, natural vanillin produced by a natural flavor (flavor) production method specified in the title of federal regulations (CFR)21, european parliament and college of affairs regulations (EC)1334/2008, or code of practice of the international food flavor industry association (IOFI) or the like is preferably used as crude vanillin.

The aliphatic dicarboxylic acid dialkyl ester in the present embodiment is not particularly limited as long as it does not inhibit the deposition of vanillin in the poor solvent crystallization described later, but is preferably selected appropriately in consideration of the boiling point close to vanillin, easy dissolution of vanillin at room temperature, and lack of reactivity with vanillin.

The boiling point of the aliphatic dicarboxylic acid dialkyl ester is preferably a boiling point close to 285 ℃, which is the boiling point of vanillin, at 1 atmosphere, and more specifically, is preferably 265 ℃ to 305 ℃. When the boiling point of the aliphatic dicarboxylic acid dialkyl ester is 265 ℃ or higher, vanillin tends to be prevented from being excessively concentrated in the post-distillation. In addition, when the boiling point of the aliphatic dicarboxylic acid dialkyl ester is 305 ℃ or lower, the vanillin tends to be prevented from being excessively concentrated in the first distillation. From the same viewpoint, the boiling point of the aliphatic dicarboxylic acid dialkyl ester is more preferably 275 to 295 ℃.

The solubility (25 ℃) of vanillin as the aliphatic dicarboxylic acid dialkyl ester is preferably 7.5% by mass or more. When the solubility is as described above, the concentration of vanillin increases during distillation, and therefore the amount of solvent can be reduced, and the production efficiency tends to be improved. Further, since the distillate during distillation can be prevented from being saturated and solidified, good production efficiency can be maintained even if no special equipment for eliminating solidification is provided. From the same viewpoint, it is more preferably 10% by mass or more.

For reference, the vanillin solubilities of the various solvents at 25 ℃ and the vanillin solubilities of the solvent-heptane mixed solvent (1: 1) are shown in table 1 below.

[ Table 1]

From the above viewpoint, the aliphatic dicarboxylic acid dialkyl ester in the present embodiment is preferably selected from the group consisting of dibutyl maleate, dibutyl succinate, diethyl sebacate, diisobutyl adipate, and a mixture thereof.

Further, from the viewpoint of preventing vanillin from being precipitated by excessive concentration due to a difference in boiling point during distillation, it is also preferable to use a mixture of an aliphatic dicarboxylic acid dialkyl ester having a lower boiling point than vanillin and an aliphatic dicarboxylic acid dialkyl ester having a higher boiling point than vanillin.

In the present embodiment, from the viewpoint of preventing the solidification and further suppressing the deposition of vanillin from the distillate, it is preferable to adjust the amount of the aliphatic dicarboxylic acid dialkyl ester so as not to be excessively small. In addition, from the viewpoint of further improving the yield of vanillin in the poor solvent crystallization described later, the amount of the aliphatic dicarboxylic acid dialkyl ester is preferably adjusted so as not to be excessive.

When the amount of the dialkyl aliphatic dicarboxylate is adjusted in accordance with the above-described viewpoint, for example, a supersaturation ratio obtained from the concentration of the distilled vanillin solution/the solubility of vanillin can be used as an index. In the present embodiment, the supersaturation ratio at 25 ℃ is preferably 1 or more and 2 or less, and more preferably 1 or more and 1.5 or less. The value of the supersaturation ratio varies depending on the kind of the aliphatic dicarboxylic acid dialkyl ester used, but in the case of dibutyl maleate, it is preferable to use 342 parts by mass (supersaturation ratio 2) to 785 parts by mass (supersaturation ratio 1), and more preferably 490 parts by mass (supersaturation ratio 1.5) to 785 parts by mass (supersaturation ratio 1) with respect to 100 parts by mass of vanillin.

(Process (B))

In the step (B), the vanillin solution obtained in the step (a) is subjected to crystallization in a poor solvent. The poor solvent crystallization is an operation of adding another solvent (poor solvent) for reducing the solubility of a solute (vanillin in the present embodiment) to a predetermined solution (vanillin solution in the present embodiment) to obtain crystals. By crystallization with a poor solvent, impurities such as substances are further removed to improve the purity, and thus purified vanillin can be obtained. In the present embodiment, the solubility can be reduced and the yield of vanillin crystals (purified vanillin) can be further improved by further cooling the vanillin solution as necessary.

From the viewpoint of preventing the oil-out phenomenon in the poor solvent crystallization, it is preferable to use a hydrocarbon solvent as the poor solvent to be added. The hydrocarbon solvent is not particularly limited as long as it is a poor solvent in poor solvent crystallization, and is preferably a hydrocarbon solvent in which the solubility of vanillin decreases when mixed with a vanillin solution containing an aliphatic dicarboxylic acid dialkyl ester, as compared with the solubility of vanillin in the selected aliphatic dicarboxylic acid dialkyl ester. From such a viewpoint, the hydrocarbon solvent is preferably selected from the group consisting of n-hexane, n-heptane, cyclohexane, and a mixture thereof. Further, from the viewpoint of obtaining vanillin crystals with better properties, it is more preferable to select from the group consisting of n-heptane, cyclohexane, and a mixture thereof. In table 1, the vanillin solubility (% by mass) of the solvent-heptane (1: 1) mixed solvent at 25 ℃ is shown by taking n-heptane as an example of the poor solvent. As can be seen from the table, when n-heptane is selected as the hydrocarbon solvent, the aliphatic dicarboxylic acid dialkyl ester is selected from the group consisting of dibutyl adipate, dibutyl maleate, diethyl sebacate, and dibutyl succinate. In this way, in the selection of the aliphatic dicarboxylic acid dialkyl ester and the hydrocarbon solvent in the present embodiment, from the viewpoint of improving the yield of poor solvent crystallization, it is preferably selected so that the vanillin solubility (25 ℃) of the aliphatic dicarboxylic acid dialkyl ester-hydrocarbon solvent (1: 1) mixed solvent becomes 3 mass% or less, more preferably 2 mass% or less.

For reference, the solubility of vanillin in the dibutyl maleate-solvent (1: 1) mixed solvent at 25 ℃ for each solvent is shown in table 2 below.

[ Table 2]

The amount of the poor solvent to be added in the poor solvent crystallization is preferably 50 to 300 parts by mass, and more preferably 100 to 200 parts by mass, based on 100 parts by mass of the vanillin solution, from the viewpoints of the yield of vanillin and the cost for using the solvent.

The temperature of the poor solvent to be added in the poor solvent crystallization is preferably 45 to 25 ℃, more preferably 40 to 30 ℃ from the viewpoint of controlling the particle size of the purified vanillin and improving the separation from the mother liquor in the filtration, depending on the kind of the aliphatic dicarboxylic acid diester used and the concentration of vanillin contained. The method of adding the poor solvent is not particularly limited, but it is preferable to add the amount necessary for spontaneous crystal precipitation first, stir for 30 to 60 minutes to precipitate crystals, and then add the remaining amount. The amount required for spontaneous crystal deposition varies depending on the combination of solvents used, and for example, when dibutyl maleate is used as the aliphatic dicarboxylic acid diester and n-heptane is used as the poor solvent, it is preferable to add 10 to 40 parts by mass, more preferably 20 to 30 parts by mass, to 100 parts by mass of the vanillin solution and to add the remaining n-heptane after confirming crystal deposition. When the poor solvent is added and then cooled, the final temperature is preferably 10 to-10 ℃, more preferably 5 to-5 ℃ from the viewpoint of the yield of purified vanillin and the energy required for cooling. From the viewpoint of further improving the yield, it is preferable to age the crystals by keeping the temperature at the target temperature and stirring for preferably 30 minutes or more, more preferably 60 minutes or more.

In the present embodiment, from the viewpoint of further improving the production efficiency of vanillin, it is preferable to further perform the following steps: a step (C) of separating the aliphatic dicarboxylic acid dialkyl ester and the hydrocarbon solvent from the crystallization mother liquor in the step (B); and a step (D) of reusing the aliphatic dicarboxylic acid dialkyl ester and/or the hydrocarbon solvent obtained in the step (C).

(Process (C))

In the step (C), the aliphatic dicarboxylic acid dialkyl ester and the hydrocarbon solvent are separated from the crystallization mother liquor in the step (B), whereby the aliphatic dicarboxylic acid dialkyl ester and the hydrocarbon solvent can be supplied to the subsequent step (D). Here, the crystallization mother liquor refers to a portion of the solution other than the crystals precipitated in the poor solvent crystallization in the step (B). The separation operation in the step (C) is not limited to the following, and examples thereof include distillation, partition extraction using a solvent, and the like.

(Process (D))

In the step (D), the aliphatic dicarboxylic acid dialkyl ester and/or the hydrocarbon solvent obtained in the step (C) are reused, and thus the aliphatic dicarboxylic acid dialkyl ester and the hydrocarbon solvent can be supplied to the steps (a) and (B) again without being discarded. The aliphatic dicarboxylic acid dialkyl ester obtained in the step (C) may be supplied to the step (a), and the hydrocarbon solvent obtained in the step (C) may be supplied to the step (B). In the step (D), the operation of reusing the aliphatic dicarboxylic acid dialkyl ester in the step (a) or the operation of reusing the hydrocarbon solvent in the step (B) may be performed separately, or both of them may be performed. Before the aliphatic dicarboxylic acid dialkyl ester and/or the hydrocarbon solvent are reused in the step (D), an operation of removing impurities present together with them by a conventional method may be performed.

(additional purification step)

In the present embodiment, by performing at least the steps (a) and (B) or, if necessary, further performing the steps (C) and (D), purified vanillin can be obtained, and from the viewpoint of further improving the purity, an additional purification step can be further performed. The additional purification step is not limited to the following, and may include, for example: a step of extracting a solution obtained by dissolving purified vanillin in water or an aqueous alcohol with a hydrocarbon solvent to remove impurities (aliphatic dicarboxylic acid dialkyl ester) derived from the step (a); and a step of removing impurities (poor solvent) derived from the step (B) by further cooling and crystallizing. These can also be carried out by applying various known purification procedures.

[ composition ]

The composition according to the present embodiment includes: 97.0 to 99.99 mass% of vanillin, 0.001 to 1 mass% of an aliphatic dicarboxylic acid dialkyl ester, and 0.001 to 1 mass% of a hydrocarbon solvent. By carrying out the above-described method for producing vanillin according to the present embodiment, the composition according to the present embodiment can be preferably obtained.

The composition according to the present embodiment more preferably contains, from the viewpoint of quality in food use, 97.0 mass% to 99.99 mass% of vanillin, 0.001 mass% to 0.01 mass% of a dialkyl aliphatic dicarboxylic acid, and 0.001 mass% to 0.01 mass% of a hydrocarbon solvent. In the above-described method for producing vanillin according to the present embodiment, the composition according to the present embodiment can be preferably obtained by performing an additional purification step.

The shape of the composition according to the present embodiment is not particularly limited, and various forms can be adopted, and crystals are preferable for convenience in food use. In this case, the color value of the reflected light of the composition (crystal of purified vanillin) according to the present embodiment evaluated by a spectrocolorimeter is preferably 88 to 96 in L a b color system, a value is-4 to +4, b value is 0 to +8, more preferably L value is 90 to 96, a value is-3 to +3, and b value is 0 to + 6. By carrying out the method for producing vanillin according to the present embodiment, a composition satisfying the color value can be preferably obtained.