JPS6259105B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for producing macrocyclic ester compounds. Macrocyclic ester compounds typified by ethylene brasylate generally have a jacquard-like aroma and are useful as musk fragrances. As is well known, this compound is produced by reacting a corresponding aliphatic dicarboxylic acid or its lower alkyl ester with an alkylene glycol, or by reacting an aliphatic dicarboxylic acid with an alkylene oxide to form a linear polyester, and then subjecting this polyester to thermal depolymerization and ring closure. This thermal depolymerization and ring-closing reaction has usually been carried out under heating and reduced pressure in the presence of a catalyst. Furthermore,
In the prior art as described above, the viscosity of the residue increases significantly due to polycondensation of the linear polyester in the reaction system and intermolecular cross-linking reaction occurring in parallel with the targeted depolymerization and ring-closing reaction. Stirring becomes very difficult and heat transfer becomes extremely poor, resulting in a decrease in yield, changes due to uneven heating, generation of cracked gas, and the quality of the distilled macrocyclic ester compound such as odor and color. There were various drawbacks such as making it worse. As a method to solve the drawback that the viscosity of the residue becomes high due to depolymerization, an example of adding an inert solvent with a high boiling point during depolymerization (Japanese Patent Application Laid-Open No. 53-56681)
The solvents used in this method are liquid paraffin and solid paraffin. It does not dissolve the polyester, but only disperses the high viscosity polymer in a relatively low viscosity medium, so in some cases the polymer may aggregate into large lumps, or a large amount of medium may be used. Therefore, the utilization efficiency of the reactor is significantly reduced. Alternatively, the distilled macrocyclic ester compound and the solvent dissolve in each other, requiring a complicated operation for separation. Alternatively, a method of depolymerizing in the presence of polyoxyalkylene glycol and its derivatives, high-boiling monohydric alcohols, monohydric fatty acids and their derivatives (Japanese Patent Application Laid-Open No. 120581/1981)
However, in this method, the ether bond of the added polyoxyalkylene glycol decomposes and produces various decomposition products, and a significant amount of decomposition gas is generated, resulting in a decrease in the degree of vacuum, and the formation of macrocyclic esters. deteriorate the quality of the compound. Another disadvantage is that the odor of monohydric alcohol, monohydric fatty acid, and their derivatives may be mixed into the distilled macrocyclic ester compound, adversely affecting the aroma as a fragrance. The present inventors previously proposed a method for producing cyclic ethylenedioate using a method similar to the method of the present invention using linear polyethylenedioate and the same type of oligoethylenedioate having a specific degree of polycondensation (specifically (Japanese Patent Application No. 56-7279), but after further detailed study, as a linear ester compound,
In addition to high polymers composed of propylene glycol and aliphatic dibasic acids, which are represented by the well-known expression aliphatic polyester, even if low-polymer condensates, which generally do not exhibit physical properties peculiar to high polymers, are used, the same type of oligomers can be used. It is possible to produce a macrocyclic ester compound by adding the like, and the oligomers to be added include propylene glycol, which is a component of the ester compound, and/or the glycol and dicarboxylic acid, which is another component. The inventors have discovered that macrocyclic ester compounds can be produced without the above-mentioned drawbacks by using monoesters, diesters, and oligoesters, and have arrived at the present invention. That is, the present invention is based on the following general formula [] [Here, either R or R' represents a hydrogen atom, the other represents a methyl group, and l represents a positive integer of 6 to 14. ] From a linear ester compound having a repeating unit, the following general formula [] [Here, R, R', and l are the same as the general formula []. ] In producing the macrocyclic ester compound represented by the general formula [], at any stage of the production, [Here, R, R', and l are the same as the general formula []. m
is a positive number indicating the average degree of polycondensation of 0 or 20 or less.
R″ is -OH group or

[Formula] is shown. ] This is a method for producing a macrocyclic ester compound, which is characterized by adding propylene glycol and/or an oligoester compound shown in the following. In the method of the present invention, the ester compound represented by the aforementioned general formula [], which is a raw material for the macrocyclic ester compound, can be produced using a conventionally known method for producing polyester. For example, HOOC−(CH ₂
) - _l Using a dicarboxylic acid called COOH or its ester-forming derivative and propylene glycol or its ester-forming derivative as raw materials, the dicarboxylic acid is converted into bis by esterification or transesterification reaction in the presence of a known catalyst if necessary. Glycol ester or low polycondensate is heated in the presence of a known polymerization catalyst to, for example, about 270°C, and as the reaction progresses, the pressure is reduced to 0.1 to 50 mmHg.
The ester compound can be produced by proceeding with polycondensation under moderately reduced pressure. As mentioned above, the ester compound is a low polycondensate that does not exhibit properties such as viscosity and elasticity characteristic of well-known polymers.
Contains high polycondensates exhibiting the above properties. The degree of polycondensation of the above-mentioned low polycondensate varies depending on the dicarboxylic acid used as a raw material, and cannot be specified.
In order to proceed with polycondensation during the production of the ester compound, the pressure required to generate and recover propylene glycol at a temperature range of 230 to 260°C is 30 to 50 mmHg.
Preferably, it is at a stage after reaching . The dicarboxylic acids that are one of the raw materials for the linear ester compound used in the present invention include suberic acid, azelaic acid, sebacic acid, nonamethylene-1.9
-Dicarboxylic acid, decamethylene-1,10-dicarboxylic acid (dodecanedioic acid), undecamethylene-
Examples include 1,11-dicarboxylic acid (brassylic acid) and thapsic acid, and examples of ester-forming derivatives thereof include methyl and ethyl esters. These acid components can be used alone or as a mixture of two or more. The other raw material is propylene glycol, and one or more of these may be used to produce a linear ester compound. As described above, in the method for producing the macrocyclic ester compound represented by the general formula [] from the linear ester compound produced, in the conventional method, polycondensation is further carried out from the linear ester compound. After the so-called high degree of polycondensation is reached, an appropriate depolymerization catalyst is added, and the macrocyclic ester compounds that are depolymerized and cyclized under heating and reduced pressure and distilled out of the system are collected. However, in this method, as mentioned above, the depolymerization reaction that generates macrocyclic esters competes with the polycondensation reaction, and the degree of polycondensation of the polyester remaining in the reactor is extremely high. Furthermore, in addition to the above two reactions, a crosslinking reaction of the linear polyester occurs, and eventually not only does stirring become impossible, but the generation of macrocyclic ester compounds substantially stops, and other decomposition reactions occur. Gas evolution occurs. On the other hand, according to the method of the present invention, by adding propylene glycol and/or an oligoester compound during the depolymerization, the degree of polycondensation of the linear ester compound in the reaction system does not increase more than necessary, and the reaction can be carried out. A macrocyclic ester compound can be generated without crosslinking from the initial stage to the final stage. Propylene glycol and/or
Alternatively, the oligoester may be any reaction product of propylene glycol, which is the raw material for the linear ester compound, or HOOC-(CH ₂ ) _-l COOH, which is another raw material, and the above-mentioned glycol, such as monoglycol. Oligomers consisting of esters, bisglycol esters, and glycol carboxylates whose average degree of polycondensation is 20 or less are preferably used. These can be used as a mixture of one or more glycols or as a reaction product of these and one or more dicarboxylic acids. In carrying out the method of the present invention, first, the linear ester compound described above is melted, stirred, and placed under reduced pressure of 50 mmHg or less to prevent the generation of propylene glycol, which is the same type of glycol that constitutes the compound. It begins. When the degree of vacuum in the system is gradually increased to about 0.1 to 1 mmHg due to the effect of a known depolymerization and cyclization catalyst added at this stage or before the start of the reaction, macrocyclic ester compounds and glycols begin to distill out, and linear esters Since the viscosity of the compound increases significantly, for example, the above general formula []
When the compound shown in is added continuously or intermittently in accordance with the distillate rate, the macrocyclic ester compound and propylene glycol are mixed simultaneously without increasing the viscosity of the linear ester compound any further. Distilled out. When oligoesters are used, the distillation of macrocyclic esters will not stop as long as this mixing continues, but it can be interrupted at any stage if necessary. As described above, by using the method of the present invention, it is possible to significantly increase the utilization efficiency of the depolymerization reactor, and if necessary, depolymerization can be completed at any stage and residual polymer can be discharged using propylene glycol if necessary. By adding additionally, it can be dissolved and discharged extremely easily. This dissolved and discharged glycol decomposition product contains bisglycol ester of dicarboxylic acid, which is a component of the linear ester compound of the general formula [], and therefore, from this decomposition product, catalyst decomposition products, etc. By separating the insoluble matter, it can be used again as part or all of the raw material for the linear ester compound represented by the above general formula []. Although the mechanism of action of the method of the present invention is not clear in detail, propylene glycol or
The addition of oligoester and oligoester causes low polymerization disproportionation of the linear ester compound, which facilitates stirring and heat transfer without increasing the degree of polycondensation compared to before addition, and at the same time, as previously thought, ring closure decomposition occurs. This is thought to be because the polymerization does not necessarily require a sufficiently high molecular weight polyester, and even linear ester compounds with a much lower degree of polycondensation can be cyclodepolymerized very easily. In the method of the present invention, all conventionally known depolymerization and cyclization catalysts can be used to produce a macrocyclic ester compound from a linear ester compound represented by the general formula []. For example, lead compounds such as lead nitrate and lead borate, composite catalysts of inorganic lead compounds such as dialkyl tin oxide, lead carbonate, and lead sulfate and alkali (alkaline earth, aluminum) alkoxides, aluminum alkoxides, aluminum compounds having carbonate groups, Examples include titanium alkoxide. The amount of these catalysts used is usually 0.1 to 0.1 to the dicarboxylic acid used as the raw material.
It is 10% by weight. This catalyst is added to the linear ester compound initially charged, and the propylene glycol or oligoester to be added may be used without any addition, or a portion of the catalyst may be added to the linear ester compound initially charged. The effect of the present invention is the same whether the above catalyst is added to propylene glycol or oligoester. By rectifying the product fraction thus distilled as necessary, it is possible to obtain a macrocyclic ester compound of high purity and having a desirable aroma. Propylene glycol and the like distilled out during the production of the ester compound, the macrocyclic ester compound, and the above-mentioned rectification can also be reused. As described above, according to the method of the present invention, a macrocyclic ester compound can be produced at virtually any viscosity, and the macrocyclic ester compound can be obtained in high yield and efficiency. EXAMPLES The present invention will be explained in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited thereto. In addition, the parts shown below indicate parts by weight unless otherwise specified. Example 1 (Production of oligomer) 1,150 parts of dodecanedioic acid, 760 parts of propylene glycol, and 1.5 parts of titanium tetrabutoxide were placed in a reactor equipped with a distillation device and a stirrer, and dehydrated at a temperature of 150 to 200°C to give approximately 36 After part of the water was distilled off, propylene glycol was removed at 210-220°C to produce an oligomer. The average molecular weight measured by the same method as described above was 550. (Production of macrocyclic ester compound) 280 parts of the above oligomer was placed in a high vacuum reactor equipped with a stirrer, and the system was gradually heated and stirred while the pressure was gradually reduced. Distillation of propylene dodecanedioate has begun. After continuing distillation for a while, the internal viscosity increased, so the internal temperature was raised to 260°C and the internal pressure was lowered to 0.3 to 0.5 mmHg.The remaining amount of the aforementioned oligomer was dissolved until the weight of the contents remained constant. The production of propylene dodecanedioate was continued. For addition of oligomers
It took 25 hours, and when the reaction was continued for an additional hour after the addition was completed, stirring became impossible, so the pressure of the system was returned to normal pressure and the reaction was terminated. The yield of the obtained propylene dodecanedioate was 1094 parts, and the yield based on the dodecanedioic acid component, taking into account the dodecanedioic acid component remaining in the reactor as in Example 3, was 98.8 parts.
It was %.

Claims (1)

[Claims] 1. The following general formula [] [Here, either R or R' represents a hydrogen atom, the other represents a methyl group, and l represents a positive integer of 6 to 14. ] From a linear ester compound having a repeating unit, the following general formula [] [Here, R, R', and l are the same as in the general formula []. ] In producing the macrocyclic ester compound represented by the general formula [], the reaction system is added at any stage of the production. [Here, R, R', and l are the same as in the general formula []. m
is a positive number indicating the average degree of polycondensation of 0 or 20 or less.
R'' represents an -OH group or [Formula].] A method for producing a macrocyclic ester compound, which comprises adding propylene glycol and/or an oligoester compound represented by the following.