JPH089574B2 - Method for producing ω-hydroxy fatty acid ester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an ω-hydroxy fatty acid ester useful as an intermediate for synthesizing a cyclic lactone used as a raw material for drugs, a fragrance or the like.

Conventional Techniques and Problems Conventional methods for producing ω-hydroxy fatty acid esters from diacid monoesters have heretofore been the methods of directly reducing diacid monoesters to ω-hydroxy fatty acid esters using diborane as a reducing agent [Journal of Chemicals]. Journal of Chemical Educatio
n) 54 , 12, p778-779 (1977)] is known.

On the other hand, as a method for producing ω-hydroxy fatty acid, ω-hydroxy-alkyl-γ-butyrolactone or ω-acyloxy-alkyl-γ-butyrolactone is subjected to catalytic reaction by supplying hydrogen gas in the presence of a hydrogenolysis catalyst. Method (Japanese Patent Publication No. 613776) or 13-oxa
A method in which bicyclo [10,4,0] -hexadecene [1 (12)] is converted into a lactone and the lactone ring is opened by the Wolff-xina method or the Juan-Minron method (Japanese Patent Publication No. 61-21474). ), And a saturated aliphatic dicarboxylic acid in the presence of a cobalt catalyst together with a saturated aliphatic glycol having the same number of carbon atoms with hydrogen (Japanese Patent Publication No. 47-4).
No. 4204) has been proposed.

However, the method for producing a diacid monoester by reduction using diborane, diborane is very expensive and dangerous to handle, and furthermore, the reaction selectivity is low and the yield of the target ester is low, Not economical for industrial scale production. In the method of catalytic hydrogenation of dicarboxylic acid, unnecessary aliphatic glycol must coexist,
It is not economical and the separation operation becomes complicated. Further, all of the above-mentioned methods for producing ω-hydroxy fatty acid use expensive and complicated compounds as starting materials, and thus have a problem of high production cost.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to provide a production method for advantageously producing a ω-hydroxy fatty acid ester in a high yield from a diacid monoester that can be obtained relatively inexpensively. .

 The present invention will be described in detail below.

The structure of the present invention is characterized by the general formula HOCO (CH ₂ ) _n COOR (I) in the presence of a cobalt catalyst, wherein R represents an alkyl group and n represents a natural number. ] The diacid monoester represented by the formula: is hydrogenated and reduced to give the general formula HOCH ₂ (CH ₂ ) _n COOR (II) [wherein R and n have the same meanings as described above]. ] It exists in obtaining the (omega) -hydroxy fatty acid ester shown by these.

Means for Solving the Problems In the present invention, the diacid monoester represented by the general formula (I) used as a starting material is obtained by esterifying an alkanedioic acid with an alcohol and using the ester, for example, barium hydroxide. It can be easily obtained by forming a monosalt of barium and then substituting the barium salt with an acid.

In this case, it is preferable to use a lower alcohol having 1 to 4 carbon atoms as the alcohol for the esterification because the obtained esterified product can be easily separated and purified.

The diacid monoester is preferably an alkanedioic acid monoester having 9 to 18 carbon atoms when it is intended as an intermediate for obtaining a lactone used as a raw material for medicines or as a fragrance.

The present invention hydrogenates and reduces the diacid monoester represented by the general formula (I) using a cobalt catalyst. Examples of usable cobalt catalysts include cobalt chloride, cobalt nitrate, cobalt sulfate, and hydroxide. Cobalt, cobalt carbonate, cobalt salts such as cobalt oxide, reduced cobalt, cobalt-diatomaceous earth, cobalt-activated carbon,
Examples thereof include reducing cobalt solid catalysts such as cobalt-alumina, Raney cobalt, and Urushibara cobalt, and cobalt complexes such as cobalt octacarbonyl and potassium pentane cyanocobaltate.

When carrying out the present invention, it is preferable to carry out under the conditions of hydrogen pressure of 1 to 200 atm and temperature of 20 to 250 ° C.

In addition, the hydrogenation reduction is performed at a hydrogen pressure of 1 atm or less and a temperature of 20 ° C.
The following is not preferable because the reduction reaction does not proceed sufficiently and the yield decreases.

Further, the higher reaction temperature and hydrogen pressure increase the reaction rate and improve the yield, but when the reaction temperature exceeds 250 ° C., the starting materials and products are decomposed and the yield decreases, which is preferable. On the other hand, even if the hydrogen pressure is higher than 200 atm, further improvement of the reaction rate cannot be expected, and a hydrogen pressure higher than this is not preferable from the viewpoint of economy and safety.

Further, this reduction reaction may be carried out in the presence of a solvent that does not participate in the reaction, such as water, benzene, toluene, cyclohexane, methanol, ethanol, ethyl acetate, dioxane and the like.

Thus, by applying the present invention, the ω-hydroxy fatty acid ester can be produced from the diacid monoester with high selectivity and high yield.

Incidentally, a part of the produced ω-hydroxy fatty acid ester may be contained in the reaction product as its oligomer, and in this case, alkali such as caustic soda and caustic potash is added and hydrolyzed under normal saponification conditions, It may be isolated and purified as ω-hydroxy fatty acid.

The ω-hydroxy fatty acid ester or ω-hydroxy fatty acid thus obtained is polymerized by a known method to give a linear polyester, which is heated and depolymerized in the presence of a depolymerization catalyst to give a cyclic lactone. Can be

 The present invention will be specifically described below with reference to examples.

Example 1 HOCO (CH ₂ ) ₁₃ COOMe → HOCH ₂ (CH ₂ ) ₁₃ COOMe 10 ml of stainless steel autoclave reduced cobalt (25 mg, 0.42 mg-atom), tridecane-1,13-dicarboxylic acid monomethyl ester (200 mg, 0.70) mmol) and toluene (2 ml) were added, and the mixture was heated with stirring at 175 ° C. for 14 hours under a hydrogen pressure of 30 atm. The analysis of methyl 15-hydroxypentadecanoate in the reaction mixture was carried out by subjecting it to the next saponification reaction.

The reaction mixture was concentrated, sodium hydroxide (300 mg),
Water (2 ml) and methanol (10 ml) were added, the mixture was heated under reflux for 1 hr, concentrated, and acidified with dilute hydrochloric acid. After extraction with ethyl acetate, the extract was dried over anhydrous sodium sulfate and the solvent was distilled off.

GLC analysis of the crude product confirmed that it contained 15-hydroxypentadecanoic acid (124 mg, 69%) and tridecane-1,13-dicarboxylic acid (13 mg, 20%),
The selectivity of methyl 15-hydroxypentadecanoate was 86%.

Example 2 HOCO (CH ₂ ) ₁₃ COOMe → HOCH ₂ (CH ₂ ) ₁₃ COOMe 10 ml of a stainless steel autoclave with reduced cobalt (50 mg, 0.84 mg-atom), tridecane-1,13-dicarboxylic acid monomethyl ester (200 mg, 0.70). mmol) and cyclohexane (2 ml), and under a hydrogen pressure of 30 atm at 175 ° C.
The mixture was heated and stirred for 14 hours. As a result of performing the same analysis as in Example 1, the conversion rate of tridecane-1,13-dicarboxylic acid monomethyl ester was 87%, and the selectivity rate of methyl 15-hydroxypentadecanoate was 77%.

Example 3 HOCO (CH ₂ ) ₁₃ COOMe → HOCH ₂ (CH ₂ ) ₁₃ COOMe In a 10 ml stainless autoclave, reduced cobalt (100 mg, 1.70 mg-atom) and tridecane-1,13-dicarboxylic acid monomethyl ester (200 mg, 0.70) were added. mmol) and dioxane (2 ml) were added, and the mixture was heated with stirring at 175 ° C. for 5 hours under a hydrogen pressure of 30 atm. As a result of performing the same analysis as in Example 1,
The conversion of tridecane-1,13-dicarboxylic acid monomethyl ester was 87% and the selectivity of methyl 15-hydroxypentadecanoate was 72%.

Example 4 HOCO (CH ₂ ) ₁₃ COOMe → HOCH ₂ (CH ₂ ) ₁₃ COOMe 10 ml of stainless steel autoclave reduced cobalt (25 mg, 0.42 mg-atom), tridecane-1,13-dicarboxylic acid monomethyl ester (200 mg, 0.70) mmol) and water (1
ml) was added, and the mixture was heated and stirred at 175 ° C. for 14 hours under a hydrogen pressure of 30 atm. As a result of performing the same analysis as in Example 1, the conversion rate of tridecane-1,13-dicarboxylic acid monomethyl ester was found to be
45%, and the selectivity of methyl 15-hydroxypentadecanoate was 82%.

Example 5 HOCO (CH ₂ ) ₁₃ COOMe → HOCH ₂ (CH ₂ ) ₁₃ COOMe In a 10 ml stainless autoclave, reduced cobalt (100 mg, 1.70 mg-atom) and tridecane-1,13-dicarboxylic acid monomethyl ester (200 mg, 0.70 mmol) was added, and the mixture was heated with stirring at 175 ° C. for 5 hours under a hydrogen pressure of 30 atm.
As a result of performing the same analysis as in Example 1, tridecane-1,13-
The conversion rate of dicarboxylic acid monomethyl ester is 51% and the selectivity of methyl 15-hydroxypentadecanoate is 78%.
It was in%.

Example 6 HOCO (CH ₂ ) ₁₁ COOMe → HOCH ₂ (CH ₂ ) ₁₁ COOMe In a stainless steel autoclave of 10 ml, reduced cobalt (25 mg, 0.42 mg-atom), undecane-1,11-dicarboxylic acid monomethyl ester (200 mg, 0.77). mmol) and toluene (2 ml) were added, and the mixture was heated with stirring at 175 ° C. for 16 hours under a hydrogen pressure of 30 atm. As a result of performing the same analysis as in Example 1, the conversion of undecane-1,11-dicarboxylic acid monomethyl ester was 24% and the selectivity of methyl 13-hydroxytridecanoate was 96%.

Example 7 HOCO (CH ₂ ) ₁₄ COOMe → HOCH ₂ (CH ₂ ) ₁₄ COOMe 10 ml of a stainless steel autoclave was prepared with reduced cobalt (25 mg, 0.42 mg-atom), tetradecane-1,14-dicarboxylic acid monomethyl ester (200 mg, 0.67). mmol) and toluene (2 ml) were added, and the mixture was heated with stirring at 175 ° C. for 16 hours under a hydrogen pressure of 30 atm. As a result of performing the same analysis as in Example 1, the conversion of tetradecane-1,14-dicarboxylic acid monomethyl ester was 22%, and the selectivity of methyl 16-hydroxyhexadecanoate was 95%.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B01J 27/232 X 27/25 X 31/20 X C07C 67/31 // C07B 61/00 300

Claims (2)

[Claims] 1. A diacid monoester represented by the general formula HOCO (CH ₂ ) _n COOR [wherein R represents an alkyl group and n represents a natural number] in the presence of a cobalt catalyst. A method for producing an ω-hydroxy fatty acid ester, which is characterized. 2. The method according to claim 1, wherein n in the general formula is 7 to 16.