JPS6145623B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing macrocyclic compounds, which are important in particular in the field of perfumery. The macrocyclic compound of interest here has the following general formula ().

[In the formula, m represents an integer in the range of 8 to 15, and n is 1
Represents an integer in the range of ~5. X is −CH ₂ −, −CO
-, Y represents _-CH2- , -O-] This macrocyclic compound () is a known substance,
Most of them have musk-like, civet-like, or amber-like scents, and they have good retention properties, so they are considered very important as fragrances. In the formula m=12, n=0, X
=Y= _-CH2- is pentadecanolide, m=11,
n = 2, X = -CO-, Y = -O- is ethylene bresylate, which is produced and used in large quantities as macrocyclic lactone-based and ester-based musk fragrances that have the best aroma properties and retention properties. has been done.

A new method for synthesizing this compound has recently been proposed [Journal of American Chemical Society, 1974, Vol. 96]
5614 pages: Chemistry Letters 1976 49
Page: Japanese Patent Publication No. 52-102287: 52-102288]. However, in these methods, reaction operations and setting of reaction conditions are difficult and complicated, and the reactants are expensive, so they are unsuitable for industrial implementation.

The simplest method that has been established industrially is to depolymerize and ring-close a linear polyester obtained by polymerizing hydroxy fatty acids or copolymerizing dibasic fatty acids and glycol [Journal of American Chemical Society, 1936, Volume 58, Page 654].

It is expressed as follows.

or In this method, the key is to obtain a macrocyclic compound from a linear polyester in a high yield as easily as possible, and therefore various depolymerization catalysts have been proposed.

For example, alkali or alkaline earth metals and their chlorides, carbonates, nitrates, cadmium, iron, lead, cobalt, manganese, tin oxides, aluminum metal, etc. have some drawbacks as catalysts. These catalysts are metals, metal salts, and metal oxides, so when using them during depolymerization, the catalyst and polyester may not mix uniformly.
Depolymerization is difficult to proceed smoothly. Furthermore, the depolymerization yield is generally low (about 60%), and a considerable amount of dimer is produced as a by-product. Among these catalysts, metal aluminum and lead oxides are considered to be particularly effective.
These particles must have a uniform particle size and there is a problem in mixing them with polyester.

In recent years, aluminum alkoxide has been used to compensate for this drawback, but since it is a special compound, it cannot be easily obtained and is therefore impractical.

The inventors have found titanium alkoxides to be highly effective depolymerization catalysts, which overcome the drawbacks of the known catalysts mentioned above.

In the present invention, any titanium alkoxide can be used as a depolymerization catalyst, but the general formula [In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are the same or different C ₁ -C ₁₈ linear or branched aliphatic alkyl groups, or aromatic substituents , Z is a halogen atom (Cl, Br, I), and r is an integer of 1 or more] is preferably used. A specific example is as follows.
(CH ₃ O) ₄ Ti, (C ₂ H ₅ O) ₄ Ti, (n-C ₃ H ₇ O) ₄ Ti,
(i−C ₃ H ₇ O) ₄ Ti, (n−C ₄ H ₉ O) ₄ Ti, (sec−
C ₄ H ₉ O) ₄ Ti, (n-C ₁₈ H ₃₇ O) ₄ Ti, (C ₆ H ₅ O) ₄ Ti,
(n- _C4H9O ) _3Ti -O _- Ti(O-n- _C4H9 ) _{3 ,}
(n- _C4H9O ) _{3TiCl .}

Furthermore, oligomers of titanium alkoxide obtained by mixing the alcoholic solution of titanium alkoxide and water or contacting with humid air, or a mixture of titanium alkoxide and titanium halide [mixing ratio 3:1 (molar ratio) or less] may also be used. is possible. Further, the titanium alkoxide may be used alone or in a mixture of two or more.

In the polyester depolymerization reaction using this catalyst, the following advantages can be enumerated compared to known catalysts.

(1) The catalyst easily dissolves in the dissolved polyester, and the depolymerization reaction proceeds quickly.

(2) Titanium alkoxide is available at low cost.

(3) Monomeric macrocyclic lactones can be obtained in high yields.

(4) Depolymerization reaction time is short.

(5) The macrocyclic lactone obtained is highly pure with almost no dimer formation.

The polyester used in the present invention may be a linear polyester obtained by polycondensation of hydroxy fatty acids or hydroxyoxa fatty acids, or a linear polyester obtained by copolymerization of dibasic fatty acids and glycol. Hydroxy fatty acids include 14-hydroxytetradecanoic acid, 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, and 18-hydroxytetradecanoic acid.
Hydroxyoctadecanoic acid, hydroxyoxa fatty acids include 14-hydroxy-12-oxatetradecanoic acid, 15-hydroxy-12-oxapentadecanoic acid, 16-hydroxy-10-oxahexadecanoic acid, 16-hydroxy-11-oxahexadecanoic acid, 16 -Hydroxy-12-oxahexadecanoic acid is an example. Dibasic fatty acids include dodecanedioic acid, tridecanedioic acid, and tetradecanedioic acid; glycols include ethylene glycol and propane-
Examples include 1,3-diol and butane-1,4-diol.

Depolymerization of polyester using titanium alkoxide as a depolymerization catalyst is carried out as follows.

Polyester is heated and dissolved, and titanium alkoxide is added to it by 0.1 to 50%, preferably 1.
Add ~10% and stir to make a homogeneous solution. This is carried out under high vacuum, e.g. 0.01 to 5 mmHg, preferably
Heat under reduced pressure of 0.1-2 mmHg. Depolymerization is 140
Depolymerization is completed in a short time by starting at ~170°C and heating to about 320°C. The produced macrocyclic compound has a high crude yield, contains almost no macrocyclic dimer in the crude product, and has almost no burnt odor. Therefore, in depolymerization using titanium alkoxide, the target macrocyclic lactone can be obtained in a higher yield and purity in a shorter time than with conventional catalysts. The most significant feature of this catalyst is that it can be easily mixed without having to pay attention to the particle size of the depolymerization catalyst or the mixing method, unlike conventional catalysts.

Examples of the present invention will be given below.

Example 1 Polyester of 15-hydroxypentadecanoic acid
Dissolve 50g, add 3.5g of titanium tetra primary butoxide, stir, and heat at 170-320℃ for 1 hour.
Depolymerization is carried out under reduced pressure of mmHg. Depolymerization begins at around 170℃ and when heated to 270℃, the initial 40
Depolymerization is almost completed within 1 minute. The mixture was further heated to 320°C to complete depolymerization and 39 g of distillate was obtained. The time required for depolymerization is 1.5 hours, which is shorter than conventional methods. The crude product contains almost no cyclic dimer and almost no burnt odor characteristic of depolymerization reactions. Since it contained a small amount of butanol, the crude product was purified to obtain 37 g of cyclopentadecanolide. bp135-137℃ (2mmHg),
mp35.5-36.5℃, spectral data matched with the standard.

Example 2 Polyester of 16-hydroxyhexadecanoic acid
50g, titanium tetra primary butoxide 3.5g
Depolymerization was carried out under the same conditions as in Example 1. The crude yield was 38 g, and after purification, 36 g of cyclohexadecanolide was obtained.

bp125-130℃ (2mmHg), mp35.0-35.7℃ Example 3 When 50g of polyester of 16-hydroxy-12-oxahexadecanoic acid and 3.5g of titanium tetra-primary butoxide are heated to 270℃ under a reduced pressure of 1mmHg, 30 The depolymerization is almost complete in minutes, but the heat is reduced to 320°C to complete the depolymerization. Crude yield 43g, after purification
40 g of 12-oxahexadecanolide was obtained.
bp 125-130°C (1 mmHg), ^n20D _1.4680 .

Example 4 50 g of polyester of 16-hydroxy-12-oxahexadecanoic acid and 3.0 g of titanium tetra secondary propoxide were depolymerized under the same conditions as in Example 3 to obtain 12-oxahexadecanolide. Crude yield 44g, 40g after purification.

Example 5 50 g of polyester of 16-hydroxy-12-oxahexadecanoic acid was depolymerized with 3.5 g of titanium tetra-primary butoxy chloride under the conditions of Example 3. Crude yield of 12-oxahexadecanolide39
g, 37 g after purification.

Example 6 50 g of polyester of 16-hydroxy-12-oxahexadecanoic acid was depolymerized with 3.5 g of a mixture of titanium tetra-primary butoxide and titanium tetrachloride (molar ratio 9:1) under the conditions of Example 3 to obtain 12- Oxahexadecanolide was obtained. gross yield
40g, 38g after purification.

Example 7 50 g of polyester of 16-hydroxy-12-oxahexadecanoic acid and 3.5 g of titanium primary butoxide dimer were depolymerized under the conditions of Example 3.
12-oxahexadecanolide was obtained. Gross yield 41
g, 38 g after purification.

Example 8 50 g of polyester of 16-hydroxy-10-oxahexadecanoic acid was added to titanium primary butoxide.
3.5 g was depolymerized under the conditions of Example 3 to obtain 10-oxahexadecanolide. Crude yield 42g, 40g after purification. bp 150-155°C (2 mmHg), n ²⁰ _D 1.4672 Example 9 50 g of polyethylene dodecanedioate is depolymerized with 3.5 g of titanium tetra-primary butoxide. When heated to 290℃ under a reduced pressure of 1mmHg, 2
Time depolymerization is almost completed. Further up to 320℃1
Heat for an hour to complete depolymerization. The crude yield was 41 g, and after purification, 38 g of ethylene dodecanethioate was obtained.
bp 125-130°C (2 mmHg), ^n20D _1.4718 .

Example 10 50 g of polyethylene brasylate is depolymerized with 3.5 g of titanium tetra-primary butoxide under the conditions of Example 9. The crude yield was 41 g, and after purification, 38 g of ethylene brasileate was obtained. bp135-140℃ (2mmHg),
n ²⁰ _D 1.4702.

Claims (1)

[Claims] 1 General formula () [In the formula, m represents an integer in the range of 8 to 15, and n is 1
Represents an integer in the range of ~5. X is −CH ₂ −, −CO
-, Y represents -CH ₂ -, -O-] In producing a macrocyclic compound represented by the general formula Linear polyester obtained by heating polycondensation of hydroxy fatty acids represented by, or the general formula Dibasic fatty acids and HO−(CH ₂ ) _o −OH represented by
1. A method for producing a macrocyclic compound (2), which comprises depolymerizing and ring-closing a linear polyester obtained by copolymerization with a glycol represented by the following using a titanium alkoxide as a catalyst.