JP4202302B2 - Process for the preparation of purified nootkaton - Google Patents

Description

  The present invention relates to a method for obtaining a purified nootkaton.

  Nootkaton is the main aroma component of grapefruit and is useful as a fragrance or flavor.

  Regardless of natural origin or synthetic origin, nootkaton has a bad odor when it takes a lot of thermal history during distillation, etc., so when using it as a fragrance or flavor, it should be removed sufficiently. It must be of satisfactory quality with the original fragrance.

  Conventionally, as a method for purifying nootkatone, a nootokatone inclusion complex is selectively formed by bringing a mixture containing nootkatone into contact with a cyclic compound such as cyclodextrin having an inclusion ability, and then the inclusion complex. There is known a method (Patent Document 1) in which nootkaton is desorbed from the water to obtain nootkatone with a purity of 60% by weight or more. However, in this method, the operation is complicated, and when the obtained nootkaton is used as a fragrance, a relatively high purity is required. Therefore, when the nootkaton is used as a fragrance, the purity is low. There was a problem.

As another method for refining Nootkaton, there is a method using precision distillation like most fragrances. However, when using nootkaton as a fragrance or flavor, the off-flavor is avoided, and in order to remove these completely and be purified to a satisfactory level, precision distillation is not efficient, and nootkaton with a good odor is increased. There was still a problem as a method for obtaining the yield.
JP 2002-47239 A

  An object of the present invention is to provide an efficient purification method for obtaining nootkatone of satisfactory quality as a fragrance with good yield.

  The present invention provides a method for obtaining a purified nootkaton by distilling a nootkatone-containing liquid at 100 to 220 ° C. in the presence of an antioxidant.

  According to the method of the present invention, it is possible to reduce the odor of nootkaton that has not reached a satisfactory level as a fragrance due to the presence of an odor due to impurities or the like, and to obtain a high-quality nootkaton that is satisfactory as a fragrance. Furthermore, side reactions such as nootkatone isomerization reaction and oxidation reaction generated by heating can be suppressed, and nootkatone can be obtained in high yield.

  The purification method of the present invention can be applied to a nootkatone-containing liquid produced by any method. For example, a method of treating valencene or nootkatol with unicellular algae or the like (see Japanese Patent Application Laid-Open No. 2003-70492), a method of treating with chromic acids (J. Food. Sci., 30, 876 (1965) Org. Chem., 34, 3587 (1969)) or a method using an imide compound catalyst (see JP 2002-145807, JP 2002-265406, JP 2001-354596, JP 2001-354611) ), Methods synthesized from readily available reagents (see J. Org. Chem., Vol. 45, page 607 (1980)), etc., or oranges, grapefruits, etc. Although it applies to what was obtained by extracting from a natural product, it is not limited to these.

  The effect of the purification method of the present invention can be exerted on the nootkaton produced by various methods. For example, in the case of a method for obtaining nootkatone by oxidation of valencene, nootkatol produced as an intermediate remains unreacted in an amount of about 0.1 to 10% by mass. If all the Nootkatol is to be converted into Nootkaton, not only a large reaction time and an oxidizing agent are required, but also the Nootkaton yield decreases due to the decomposition or polymerization of Nootkaton.

  On the other hand, in order to separate the remaining Nootkatol from the Nootkaton by precision distillation, it is necessary to perform precision distillation with a sufficient reflux ratio. However, if a sufficient reflux ratio is applied, the isomerization of nootkatone to the olefin isomer proceeds and the nootkaton yield decreases.

  In the case of a method of extracting from a natural product such as orange or grapefruit, a variety of components are mixed in the natural product, and usually a compound having a boiling point close to that of Nootkaton is present in these components. Even if precision distillation is performed as a method for removing these components from Nootkaton, a sufficient reflux ratio is necessary as described above, and there is still a problem of yield reduction accompanying isomerization of Nootkaton.

  In the method of the present invention, for example, in the above-mentioned scene, distillation in the presence of an antioxidant suppresses isomerization of nootkatone, and a sufficient reflux ratio is applied to remove impurities such as nootkatol. Rectification can be performed.

  The nootkatone-containing liquid to be subjected to the purification method of the present invention may be a mixture containing nootkatone obtained by the reaction, or a purified product obtained by purification by a normal purification method after completion of the reaction. Examples of such purified products include those that are still inadequate after purification by conventional methods, those that have become odorless in quality inspection after rectification, and those that have deteriorated during storage and have a strange odor. Examples include those that do not detect impurities by gas chromatography but have a foul odor. The nootkaton that can be suitably purified according to the present invention includes either (+)-nootkaton or (−)-nootkaton. Among these, the purification method of the present invention is preferably applied to a nootkatone-containing liquid obtained by a method of oxidizing valencene. The amount of nootkatone contained in the nootkatone-containing liquid is not particularly limited, but is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, and still more preferably 40 to 75% by mass from the viewpoint of yield.

  Examples of the antioxidant used in the purification method of the present invention include all commonly used antioxidants. For example, “Chemical Products of 14102” (Chemical Industry Daily) pages 1107 to 1116, pages 1430 And antioxidants described on pages 1 to 1434. Among these, a phenolic antioxidant is preferred because it can obtain a nootkaton having a good odor in a small amount. Examples of the phenolic antioxidant include monophenolic antioxidants such as dibutylhydroxytoluene, bisphenolic antioxidants such as 2,2′-methylenebis- (4-methyl-6-tert-butylphenol), tetrakis- [ Methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] and high molecular phenolic antioxidants such as methane or tocopherols. Among these phenolic antioxidants, a compound having a boiling point higher than that of nootkatone is more preferable from the viewpoint of suppressing the mixing of the antioxidant into the fraction.

  The amount of the antioxidant is preferably 0.01 to 5% by mass, more preferably 0.03 to 3% by mass with respect to the treated nootkatone-containing liquid from the viewpoint of suppressing side reactions such as off-flavor generation and isomerization reaction. 0.05 to 0.5% by mass is preferable.

  The distillation in the purification method of the present invention is carried out at 220 ° C. or lower, preferably 200 ° C. or lower, more preferably 180 ° C. or lower, from the viewpoint of suppressing decomposition or polymerization of nootkatone or other inclusions. Further, from the viewpoint of productivity and ease of control of the decompression conditions, the temperature is preferably 100 ° C. or higher, more preferably 130 ° C. or higher, and still more preferably 160 ° C. or higher. Further, the distillation is preferably performed under reduced pressure in order to prevent temperature rise, more preferably in the range of 0.01 to 0.67 kPa, and particularly preferably in the range of 0.05 to 0.45 kPa.

  As the distillation method, precision distillation is preferable. Specifically, the low-boiling odor component is relatively large in reflux ratio, preferably 5 to 30, more preferably 8 to 25, and still more preferably 10 to 20. After distilling, the nootkatone having a good odor is preferably distilled at a reflux ratio of 0.1 to 5, more preferably 0.5 to 2.5. By such a method, the side reaction in a refinement | purification process can be suppressed and the high quality nootkaton which can be used as a fragrance | flavor and does not have a bad smell is obtained with a high yield.

  Examples of the precision distillation apparatus that can be used in the present invention include generally used precision distillation apparatuses. The number of stages is 5 to 50, preferably 10 to 20, and the packing is, for example, Helipak (Tokyo Special). Examples thereof include, but are not limited to, wire mesh (manufactured by Sumitomo Heavy Industries, Ltd.) and sulzer packing.

Example 1
To 2,0.5'-methylenebis- (4-) was added to 300.5 g of noutkatone-containing liquid prepared according to the method described in Example 1 of JP-A-2002-265406 using valencene (including 142.4 g of pure nootkaton). Methyl-6-t-butylphenol) (Yoshinox 2246G, manufactured by Yoshitomi Fine Chemical Co., Ltd., 0.30 g) was added, and a 20-stage precision distillation apparatus (Sulzer Lab Packing DX (manufactured by Sumitomo Heavy Industries, Ltd.)) was used. And distilled under reduced pressure. Specifically, after removing off-flavor components by applying a reflux ratio of 10 at a vacuum of 0.27 kPa, the reflux ratio was changed to 1 and the temperature in the tank was raised to 190 ° C. to obtain a nootkaton fraction. . Distilled matter was collected in units of 10 ml, and composition analysis was performed for each collected sample to obtain a pure nootkaton content obtained by distillation. The net fraction of Nootkaton contained in all recovered fractions was 131.7 g (recovery rate 92.5%). In addition, from the sample of 10 ml unit recovered by distillation, it has a good grapefruit-like flavor with reduced off-flavor, and the total mass of the sample from which a good quality nootkaton was obtained as a fragrance was obtained. Yield. The yield of nootkaton was 47.6 g.

Example 2
To 300.0 g of a nootkatone-containing solution prepared according to the method described in Example 1 of JP-A-2002-265406 using valencene (including 143.0 g of nootkaton pure content), δ-tocopherol (Emix D, Eisai ( 0.31 g) was added and distilled under reduced pressure using a 20-stage precision distillation apparatus (Sulzer Lab Packing DX (manufactured by Sumitomo Heavy Industries, Ltd.)). Specifically, after removing off-flavor components by applying a reflux ratio of 10 at a vacuum of 0.27 kPa, the reflux ratio was changed to 1 and the temperature in the tank was raised to 190 ° C. to obtain a nootkaton fraction. . In the same manner as in Example 1, the nootkaton purity (recovery rate) and yield were determined. The net fraction of nootkaton contained in all recovered fractions is 131.5 g (recovery rate 92.0%). Of the nootkaton fraction, it has a good grapefruit-like flavor with reduced off-flavor and good quality as a perfume. The yield of some Nootkaton was 47.0g.

Comparative Example 1
In Example 1, precision distillation was performed in the same manner except that Yoshinox 2246G was not added to the nootkaton-containing liquid, and a nootkaton fraction was obtained. In the same manner as in Example 1, the nootkaton purity (recovery rate) and yield were determined. The net fraction of nootkaton contained in all recovered fractions was 125.5 g (recovery rate 87.9%), and the yield of good quality nootkaton was 18.7 g.

The amount of isomers produced was 11.0 g in Example 1 and 11.0 g in Example 2, and the isomerization reaction was suppressed by the method of the present invention compared to the amount produced 18.7 g in Comparative Example 1. I understand. That is, in the method of the present invention, it is possible to obtain a nootkatone purified with a high yield by suppressing the isomerization reaction and the like by the antioxidant.

Claims (3)

  A method of distilling a nootkatone-containing liquid at 100 to 220 ° C. in the presence of an antioxidant to obtain a purified nootkaton.   The method of obtaining the refined nootkaton of Claim 1 whose quantity of antioxidant is 0.01-5 mass% with respect to a nootkatone containing liquid. The method for obtaining a purified nootkaton according to claim 1 or 2, wherein the antioxidant is a phenolic antioxidant.