JPH0434554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Macrocyclic esters are obtained by thermal depolymerization of corresponding linear polyesters with ring closure. For such a process, the polyester is heated at elevated temperature in the presence of a catalyst. The reaction is conducted under reduced pressure and macrocycles and other volatile products formed during the course of depolymerization are removed from the reaction zone as they are formed.

It has been shown in US Pat.
Described in No. 092,031. US Patent No.
In the method in No. 4165321, No. a, a,
Lewis metal salts such as oxides, hydroxides, halides or carboxylates of group metals b, a, b and group metals have been shown to be useful catalysts. Yasakawa et al. used lead catalysts (oxides, hydroxides,
carbonates, nitrates, borates, or organic acid salts) [Chemjcal
Abstracts, Vol.78 (1973), 158996q and
158968s]. Cyclic esters can also be obtained by thermal decomposition of polyesters using SnCl ₂ 2H ₂ O [Chemical Abstracts Vol. 86 (1977),
156163s]. U.S. Pat. Nos. 4,105,672, 4,136,098 and 4,157,330 disclose that tin carboxylates and organotin compounds are
-di-t-butyl-4-hydroxybenzine) phosphate is used in combination to impart a desolvation effect to the depolymerization reaction. A related method is described in British Patent No. 1108720.
The preparation of cyclic ester anhydrides of alpha-hydroxycarboxylic acids by vacuum depolymerization of the corresponding linear polymers at 200 DEG -240 DEG C. in the presence of lead stearate () is described.

Considering the problems associated with the use of heavy metal catalysts, Ciekoslovakia Patent No. 108762 proposed that aluminum oxide catalyzes depolymerization carried out at atmospheric pressure using superheated steam. . The use of metal aluminum was also introduced in 1975.
No. 1, it was reported for use in the depolymerization of polyesters for the production of cyclic esters and lactones. Aluminum alcoholate is described in Japanese Patent Publication No. 47-25071 for use in the production of macrocyclic lactones.
Japanese Patent Application No. 115390/1983 describes the method for depolymerization-cyclization reaction.
It is described that macrocyclic ethylenediolates can be obtained using aluminum compounds with CO ₂ radicals. This aluminum compound is made from an aqueous mixture of aluminum hydroxide and caustic soda with _CO2
It can be obtained by processing with Alternatively,
Aluminum hydroxide can also be reacted with aqueous sodium carbonate to obtain the catalyst used in the above process.

The present invention relates to an improved process making it possible to produce macrocycles by thermal depolymerization of polyesters, characterized in that natural or synthetic dowsonite is desolvated and used. According to the method of the invention, a significant increase in reaction rates can be achieved. Furthermore, a macrocyclic compound that does not contain heavy metal residues, which are often problematic, can be obtained conveniently and economically.

For the improved method of the invention, a linear polyester is heated under reduced pressure at a temperature in the range of 200 DEG C. to 400 DEG C. in the presence of 0.01 to 10% by weight of catalyst, based on the polyester. Typically depolymerization is about 10mm
Pressures from Hg to 0.01 mm Hg are carried out, and the catalyst is present in an amount of about 0.1 to 5% by weight, based on the polyester. Macrocyclic products having 8 to 20 carbon atoms in the ring are obtained by the process of the invention.

The present invention relates to a process for producing macrocycles having 8 to 20 carbon atoms in the ring by depolymerization of linear polyesters with ring closure. This method uses natural or synthetic dowsonite as a catalyst.

The polyesters used in these depolymerization methods are obtained by conventional methods well known in the art. Preference is given to using polyesters terminated with monocarboxylic acids and/or monofunctional alcohols to control the molecular weight and viscosity of the polymer. Polyesters with acid and hydroxyl values of about 20 or less, more usually 10 or less, are particularly useful. The degree of polymerization of the polyester generally ranges from about 5 to 150, but can be higher if desired. Useful polyesters are common dicarboxylic acids,
Derived from diols and hydroxymonocarboxylic acids. The dicarboxylic acids used are preferably aliphatic, may be saturated or contain olefinic unsaturation, and may be branched or straight-chain. However, it is also possible to use aromatic or cycloaliphatic dicarboxylic acids.

The dicarboxylic acid typically contains from 3 to about 18 carbon atoms, more preferably from about 8 to about 14 carbon atoms.
Contains up to 5 carbon atoms. Particularly useful carboxylic acids include malonic acid, maleic acid, succinic acid, glutaric acid, adivic acid, pimelic acid, azelaic acid, sebacic acid, undecanedioic acid,
These include dodecanedioic acid, brassylic acid, and pentadecanedioic acid. It is also possible to use two or more dicarboxylic acids. Particularly preferred are _C9 - _C13 saturated aliphatic dicarboxylic acids. This is because the macrocycles prepared therefrom exhibit particularly desirable aroma properties and are useful in a wide variety of cosmetic applications.

The diols for reaction with the dicarboxylic acids mentioned above are primary aliphatic diols having 2 to 12, more preferably 2 to 6 carbon atoms. Diols are preferably saturated and can be either straight chain or branched. Useful diols include ethylene glycol, 1,2- or 1,3
-propanediol, 1,2-1,3 or 1,
4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol,
2,3-dimethyl-2,3-butanediol,
Examples include 1,8-octanediol, 2-ethylhexanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol, and tetraethylene glycol. Cycloaliphatic diols such as 1,4-cyclohexadimethanol can also be used. Polyesters derived from ethylene glycol and di-, tri-, and tetraethylene glycols are particularly advantageous for use in the depolymerization process of the present invention.

Hydroxymonocarboxylic acids from which useful polyesters can be derived include 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, 10-oxa-16-hydroxyhexadecanoic acid, 11-oxa-16-hydroxyhexadecanoic acid, 12-oxa- 16-hydroxyhexadecanoic acid, 10-thia-16
-hydroxyhexadecanoic acid, 11-thia, 16-hydroxyhexadecanoic acid, 12-thia-16-hydroxyhexadecanoic acid, and the like.

Using polyesters of the type mentioned above, macrocycles with 8 to 20 carbon atoms in the ring can be obtained. This macrocycle conforms to the following general formula.

[However, R' in the formula is a branched or straight chain saturated or unsaturated divalent aliphatic hydrocarbon group having 1 to 16 carbon atoms, and R' is a divalent aliphatic hydrocarbon group having 1 to 16 carbon atoms. a saturated divalent aliphatic hydrocarbon group having atoms, and x is an integer from 1 to 4], or [However, R in the formula is a divalent aliphatic hydrocarbon group having 6 to 18 carbon atoms], or [wherein R″, R and x are as defined above and A is oxygen or sulfur] Particularly useful macrocyclic compounds of formula (a) are those in which R′ is 6 to 12
a saturated aliphatic radical having 2 to 6 carbon atoms, the aliphatic radical R″ having 2 to 6 carbon atoms, and x being 1 or 2. Formulas (b) and (c) Preferred macrocycles are those in which R is a saturated divalent aliphatic hydrocarbon group having 10 to 14 carbon atoms, the aliphatic group R'' contains 2 to 6 carbon atoms, A is oxygen, and x is 1 or 2.

Examples of macrocyclic products that can be produced by the depolymerization method of the present invention include: 3, 6,
9-tridecamethylene malonate, dodecamethylene malonate, decamethylene malonate, ethylene suberate, ethylene azelate, 3-oxa-pentamethylene azelate, 3-methylpentamethylene sebacate, ethylene undecanediolate, ethylene Dodecanediolate, ethylene brassylate, ethylene-α-methylbrassylate, ethylene-α,α-dimethylbrassylate,
Ethylene-α-ethylbrasylate, pentadecanolide, 12-oxa-pentadecanolide, 12
-thia-pentadecanolide, hexadecanolide, 10-hexadecanolide, 11-oxa-hexadecanolide, 11-thia-hexadecanolide,
12-oxa-hexadecanolide, etc.

The macrocyclic compounds obtained from the process of the invention are primarily useful for cosmetic applications. These compounds impart desirable aroma characteristics and/or enhance the aroma characteristics of other compounds with which they are combined. For example, these compounds are found in detergents (heavy duty or regular wash), soaps (bar soaps, dry soaps and special beauty soaps), personal cosmetics (bath oils, shampoos,
Can be used in hair rinses, deodorants, shaving creams, and toothpastes)
Also perfumes, fragrance oils, fragrance fixatives, colognes,
It can be used as an aromatic ingredient for post-shave lotions and the like. The products obtained according to the invention are particularly suitable for applications where heavy metal residues are unacceptable.

Rapid reaction rates as well as high yields of the desired macrocyclic products are obtained by the process of the present invention using dowsonite as the catalyst for the reaction. Dowsonite, a basic carbonate of sodium and aluminum, is a naturally occurring mineral and is the subject of a U.S. patent.
It can also be produced synthetically by the method described in No. 4238458. Dowsonite is a colorless to white crystalline solid containing approximately 19% aluminum and 16% sodium, and its chemical composition is given in the literature by the following formula:

NaAl( _CO3 )(OH) _{2Al2O3 ・}Na2O_{・ 2CO2 ・ 2H2O} AlNaO(OH) _{HCO3 AlNa3} ( _CO3 ) ₃・2Al(OH) _3For the purposes of the present invention Dowsonite, either a naturally occurring mineral or synthetic, can be used to achieve the desired results. The amount of dowsonite ranges from about 0.01% to about 10% by weight based on polyester.
It can range up to % by weight. Most commonly around
From 0.1 to about 5% by weight of dowsonite is used for the process of the present invention.

In addition to improving reaction rates and providing high yields of macrocyclic products, the process of the present invention is also advantageous in that it avoids the use of heavy metals. The presence of even small amounts of heavy metals in macrocycles is harmful. The presence of such metal contaminants promotes the formation of decomposition products that impart undesirable color or odor to the macrocyclic product or otherwise detract from the overall desirable properties of the product. .

The method of the invention can be carried out according to already established methods. Thermal depolymerization is well known and reference may be made in this respect to the prior art already mentioned. This depolymerization method is typically
Temperatures ranging from 200℃ to 400℃, more commonly 250℃
It is carried out at temperatures ranging from °C to 360 °C. Subatmospheric pressures are used to facilitate removal of the macrocycles that form. The process is generally conducted at a pressure of about 50 mm Hg or less, and more preferably the pressure is in the range of about 0.1 mm Hg to 10 mm Hg.

The temperatures, pressures and amounts of decomposition used in the process of the invention will vary depending on the particular polyester being decomposed, the method of operation and the equipment design. The process of the invention can be carried out as a batch, continuous or semi-continuous operation using conventional processing equipment in which the macrocyclic products formed during the depolymerization process can be removed by vacuum distillation. The catalysts used in this invention are equally effective in batch-type operations or in continuous or semi-continuous operations such as those described in US Pat. No. 4,165,321. When carrying out the process of the invention continuously or semi-continuously, the dowsonite can be added continuously or incrementally throughout the course of depolymerization.

The following examples are intended to explain the present invention in more detail, but are not intended to limit the scope of the present invention.
In these examples, all parts and percentages are by weight unless otherwise specified.

EXAMPLE 1 To prepare poly(ethylene brassylate), 109 parts of dimethylbrasylate and 30.5 parts of polymer grade ethylene glycol were charged into a resin kettle equipped with a stirrer, a distillation head, and a condenser. Approximately 2.5% based on dimethylbrasylate
C _16-22 mixed fatty acid methyl ester was included as a chain terminator _. Then, U.S. Patent No.
A supported titanium catalyst (0.08 parts) prepared from tetraisopropyl titanium and natural acidic montmorillonite clay according to the method of No. 4032550 was added under positive nitrogen pressure, and heating was started. When the temperature reached approximately 180°C, methanol began to distill from the reaction mixture and was collected. When most of the methanol was removed, the temperature was increased to approximately 195-205°C and vacuum was applied. The vacuum was gradually increased to about 30 inches Hg and held for about 4 hours. The poly(ethylene brasileate) was then cooled to about 180°C and filtered off over the supported titanium catalyst. The resulting product had a viscosity of 117 cst. at 210°C.

0.54% by weight of Dowsonite (obtained from Alcoa Chemicals, Bauxite, AR) was added to a portion of the poly(ethylene brasylate) produced as described above to form poly(ethylene brasylate) as disclosed in U.S. Pat. No. 2,092,031. It was depolymerized by the method described in . A glass reactor with a take-off condenser was used for the depolymerization. Mix the mixture first to approx.
It was heated to 160-180°C to fully disperse the dowsonite in the polymer. Then the temperature of the reaction mixture is
The temperature was increased to 340° C. and the pressure maintained at 1-1.5 mm Hg while the ethylene brasileate distillate was removed.
After about 90 minutes, a 90% yield of crude ethylene brasileate was obtained. The poly(ethylene brassylate) was substantially completely depolymerized within 2 hours.

Example 2 Poly(ethylene brasileate) was depolymerized as in Example 1 using synthetic dowsonite produced by the method of US Pat. No. 4,238,458.
For catalyst production, 43 parts of sodium bicarbonate and
13.5 parts of aluminum hydroxide were slurried in 264 parts of water and the mixture was heated in a stirred autoclave at 220° C. and 225 psig for 3 hours. The autoclave was then cooled to 50°C, evacuated and the reaction mixture filtered. The solid product was washed with water, air dried, ground in a hammer mill and sieved to less than 60 mesh. Analysis of the product of the synthesis obtained shows 18.182% Al and 15.746% Na (theoretical values:
18.8%Al, 16.0%Na). This synthetic dowsonite was dispersed in poly(ethylene brasileate) at a concentration of 0.59% by weight and the mixture was heated at 340°C.
(1-1.5 mmHg). After 90 minutes, ethylene brassylate was obtained with a yield of 87.7%. When synthetic dowsonite was used at 1% crystal concentration, similar ethylene brasylate yields were obtained and the poly(ethylene brasrylate) was substantially all depolymerized within 105 minutes.

Example 3 (Comparative Example) In order to demonstrate the significantly superior and unexpected results obtained by the method of the present invention using dowsonite, a sample was prepared according to the teachings of JP-A-54-115390. The following comparative experiment was conducted using the same catalyst. A probe was manufactured by the method described in Comparative Example 1 in JP-A-54-115390. When this catalyst was analyzed, it was 27.6
% aluminum and 7.1% sodium. This catalyst was dispersed in poly(ethylene brasileate) at a concentration of 2.4% by weight and depolymerized according to the method of Example 1. Even though the amount of catalyst was approximately four times higher than that used in Example 1, only a 66% yield of ethylene brasylate was obtained after a reaction time of 90 minutes. From the above data, it is clear that the compound of JP-A-54-115390 is not as effective a catalyst for the depolymerization of poly(ethylene brasileate) as dowsonite, even when used at fairly high concentrations.

Example 4 To demonstrate that the reaction can be carried out continuously, poly(ethylene brasileate) was depolymerized by the method of US Pat. No. 4,165,321. For the reaction, 0.54% by weight of dowsonite was dispersed in poly(ethylene bra sheet) and transferred to a stainless steel holding tank at 100°C with stirring.
was held at Polyester was continuously metered from this tank into an electrically heated stainless steel inverted vertical conical reactor equipped with two conical spiral blades. The axes of the above blades coincide with the conical axis of the reactor, and these blades are interlocked with each other so as to rotate in the reaction direction, so that the entire volume of the reaction mixture is very efficiently distributed. Mixing is possible from top to bottom. The blades are arranged in the reactor so that the maximum gap between the blades and the wall is about 0.25° and are rotated by a high torque motor at about 20 rpm. Heat the reaction mixture to 330 °C to 360 °C for depolymerization.
The temperature was maintained at a temperature in the range of 0.degree. C. and a pressure of 1-5 mm Hg. Ethylene brasylate was continuously distilled from the reactor and the addition rate of the dowsonite-containing polyester was adjusted as necessary to maintain proper mass balance. The reactor was operated continuously for 32 hours, resulting in an overall yield of 79.5% crude ethylene brassylate.

Claims (1)

[Claims] 1. Polyester is heated at 200℃ or less at a pressure of 50mmHg or less.
A process for producing macrocyclic compounds having 8 to 20 carbon atoms in the ring, comprising thermally depolymerizing the polyester by heating to a temperature of 400°C and recovering the resulting cyclic product. and the above depolymerization is 0.01 to 10% by weight based on the polyester.
A method characterized in that it is carried out in the presence of natural dowsonite or synthetic dowsonite as a dissolving medium. 2 Catalyst 0.1 based on the weight of polyester
Claim 1 present in an amount of ~5% by weight
The method described in section. 3 Depolymerization is carried out at temperatures ranging from 250℃ to 360℃ and
The method according to claim 1 or 2, which is carried out at a pressure of 0.01 mmHg to 10 mmHg. 4. The method according to any one of claims 1 to 3, wherein the depolymerization is carried out as a continuous or semi-continuous operation. 5. The method according to any one of claims 1 to 4, wherein the polyester is a linear polyester. 6. The method according to claim 5, wherein the polyester is terminated with a monocarboxylic acid and/or a monofunctional alcohol. 7. The method according to any one of claims 1 to 4, wherein the polyester is poly(ethylene brasillate) and the macrocyclic product is ethylene brasillate.