JPH0152393B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for producing macrocyclic ethylenedioate, and more particularly to an industrially improved method for producing highly purified macrocyclic ethylenedioate in a simple manner and in high yield. Macrocyclic ethylenedioate, represented by ethylene brasylate, generally has a jacquard-like aroma and is a compound useful as a musk fragrance. As is well known, this macrocyclic ethylenedioate can be obtained by reacting the corresponding aliphatic dicarboxylic acid and ethylene glycol or aliphatic dicarboxylic acid and ethylene oxide to form a linear polyester, and then subjecting the polyester to thermal depolymerization and ring closure. has been
This thermal depolymerization ring-closing reaction is usually carried out under heating and reduced pressure in the presence of a catalyst, and most of the prior art studies have focused on catalysts used in this ring-closing reaction. That is, the general production method found in the prior art uses dicarboxylic acid or its lower alkyl ester and ethylene glycol, or dicarboxylic acid and ethylene oxide, and if necessary, finally in the presence of a polycondensation catalyst, which can be exemplified by an antimony compound. Polycondensation is performed at a temperature of 200 to 300°C under a pressure of 0.1 to 20 mmHg to obtain a linear polyester, and then a known depolymerization catalyst is added and depolymerization is performed under a pressure of 0.1 to 20 mmHg to close the ring. Cyclic ethylenedioate is obtained by collecting the generated cyclic ethylenedioate by distillation and rectifying this fraction, but in particular, depolymerization with improved aroma and yield has been adopted. As a catalyst, lead compounds (Japanese Unexamined Patent Publication No.
-26790), organic tin compounds (JP-A-1983-26790)
51385), but when these prior known catalysts are used, the polycondensation of the linear polyester in the reaction system proceeds further in parallel with the target depolymerization and ring-closing reaction. Not only does the viscosity of the residue increase markedly as cyclic ethylenedioate is produced and distilled off, but as depolymerization progresses, a so-called intermolecular crosslinking reaction occurs, causing the linear polyester to become insoluble, and eventually A gelatinous state is reached and stirring becomes impossible. As a result, the yield decreases, carbonization due to non-uniform heating and generation of decomposed gas occur, and even the odor, color and other quality of the distilled cyclic ethylenedioate deteriorates. Another drawback was that the infusible resin stuck to the reactor, making it very difficult to remove it after the reaction was completed. In order to eliminate these drawbacks, there is an example of prior art in which an inert solvent with a high boiling point is added into the reactor during the depolymerization and ring-closing operation (Japanese Patent Application Laid-Open No. 56681/1983).
However, the solvents substantially used in this method are liquid paraffin and solid paraffin, and as is well known, these solvents do not dissolve the linear polyester mentioned above, and the high viscosity polymer has a relatively low viscosity. However, in some cases, the polymer may aggregate into large lumps, or the use of a large amount of medium may significantly reduce the efficiency of reactor utilization. In addition, as with the simple depolymerization method described above, insoluble matter is likely to be generated,
There was a problem in removing the residue after the reaction was completed. The present inventors not only smoothly obtained macrocyclic ethylenedioate with excellent aroma in high yield without using any special equipment or additives that do not participate in the reaction, but also after the reaction. After considering how to easily discharge the residue remaining in the reactor and to reuse most of this discharge, we found that by adding a specific amount of a specific titanium compound as a depolymerization catalyst, these The inventors have discovered that the problems can be solved all at once and have arrived at the present invention. That is,
The present invention relates to a fatty acid represented by the following general formula ()ROOC( _CH2 )lCOOR () (in the formula, l is a positive integer from 6 to 14, and R represents either a hydrogen atom or a lower alkyl group) group dicarboxylic acid or its ester and ethylene glycol, or the general formula ()
An aliphatic dicarboxylic acid represented by the formula and ethylene oxide are polymerized to form a linear polyester, and this polyester is depolymerized to form a (wherein l represents a positive integer of 6 to 14), titanium trichloride or the following general formula () Ti ( OBu) m (OH) n Represents a positive integer from 2 to 4.However, m+n+q=4, one of m, n, and q is always 0, and if m is 0, n is 0,
q is 4. ) is a method for producing cyclic ethylenedioate, which is characterized in that a titanium compound represented by: 0.01% by weight or more and less than 0.1% by weight is added to the polyester. According to the method of the present invention, the residual polymer does not become extremely crosslinked and become infusible as the cyclic ethylenedioate is distilled out of the reaction system. Therefore, it can be stirred with a stirrer capable of stirring a highly polymerized polymer, and the residue after the reaction is not only easily dissolved and discharged using a compound such as ethylene glycol, but also this discharged material (as described above) can be easily dissolved and discharged using a compound such as ethylene glycol. (predominantly glycol esters of dicarboxylic acids such as dicarboxylic acids) can again be used as a raw material for the macrocyclic ethylenedioate. In addition, since uniform heating is possible, generation of decomposition gas and carbonization of the polymer can be prevented, and various drawbacks of conventional methods can be solved at once, such as high quality cyclic ethylenedioate can be obtained at a high yield. The titanium compound of the present invention can also be used as an effective polycondensation catalyst between an aliphatic dicarboxylic acid or its ester and ethylene glycol, or an aliphatic dicarboxylic acid and ethylene oxide. That is, normally this polycondensation does not necessarily require a catalyst, but it is often used to accelerate the reaction. If the titanium compound used in the present invention is added during the production of linear polyester, polyesterification can be effectively carried out. The present invention also has the advantage that the two-step process of polycondensation and depolymerization seen in the conventional method can be simplified into a one-step process in that cyclic ethylene dioleate can be produced successively by setting the temperature to the thermal depolymerization temperature. have. The aliphatic dicarboxylic acids having the general formula () or esters thereof used in the present invention include suberic acid, azelaic acid, sebacic acid,
undecanedioic acid, dodecanedioic acid, brassylic acid, tridecane-1,13-dicarboxylic acid, thapsic acid and their methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, or tertiary It is a butyl ester. Further, in the titanium compound having the general formula (), the substituent Bu represents a butyl group, and X represents a halogen atom, preferably chlorine or bromine. In addition to titanium trichloride, the catalyst used in the present invention includes compounds represented by the above general formula (), and specific examples of these preferred compounds include titanium tetrachloride, titanium tetrabromide, Examples include various titanium compounds such as tetra-n-butoxy titanium, tri-n-butoxy titanium hydroxide, di-n-butoxy titanium dichloride, and di-n-butoxy dibromide. These compounds can be used as a mixture if necessary, or can also be used as a mixture with known polycondensation and depolymerization catalysts. The method of carrying out the present invention is to perform heating polycondensation by dehydration or dealcoholization and deglycol using 1 to 2 moles of ethylene glycol (or ethylene oxide) per mole of dicarboxylic acid or its ester to obtain a linear polyester, and then under reduced pressure. Upon heating, the cyclic ethylenedioate produced by depolymerization and ring closure is continuously distilled out of the system, and this separated fraction is purified to obtain highly pure cyclic ethylenedioate having a favorable aroma. Although linear polyesterification normally proceeds without a catalyst, a polycondensation catalyst such as antimony trioxide may be used to accelerate the reaction, but as mentioned above, the titanium compound used in the present invention may be If it is added during production of polyester, there is no need to use other polycondensation catalysts. That is,
The titanium compound may be added at any stage from polycondensation of dicarboxylic acid or its ester and ethylene glycol or dicarboxylic acid and ethylene oxide to depolymerization and ring closure reaction. The amount of titanium compound used as a catalyst is based on the linear polyester used in the depolymerization and ring-closing reaction.
Less than 0.1% by weight is preferred. However, this amount of usage
If it is less than 0.01% by weight, the formation of cyclic ethylenedioate will be slowed down, which is not preferable. Furthermore, if the amount of the catalyst used is 0.1% by weight or more, as the depolymerization reaction progresses, especially from the latter half of the reaction, the crosslinking reaction in the linear polyester as a raw material becomes noticeable, and the amount of 0.1% by weight increases. This is undesirable because the yield of the ethylenedioate is lower than when using less than 30% of the total amount of ethylenedioate.Moreover, since the degree of crosslinking is extremely high, even if you try to decompose and dissolve the residue in the reactor with, for example, ethylene glycol after the reaction is completed, it will not be possible to completely dissolve it. It is difficult to dissolve, and residue often adheres to the reactor wall, making it impossible to completely discharge it.Furthermore, for reasons that are unclear, the residue remains as it is, and new raw materials are added to the macrocycle. When ethylenedioate is produced, the yield based on the newly added dicarboxylic acid component is extremely low, and this residue causes some effects, so the residue must be removed by an appropriate method each time a reaction is performed. Must be. Further, although the details are unknown, in addition to the above-mentioned crosslinking reaction, the reaction of producing a decomposition product that deteriorates the aroma of the ethylenedioate is also accelerated, which is undesirable. In addition, as is well known, polycondensation is carried out under a pressure of 0.1 to 20 mmHg at a temperature of 200 to 250 mmHg.
It is carried out at a temperature of °C. The degree of polymerization is determined by the polycondensation conditions, but if the molecular weight is greater than the extent that it will not be distilled off under the depolymerization conditions to obtain cyclic ethylenedioate in the depolymerization ring-closing reaction, specifically, it is more than a mer. If so, the purpose of the present invention can be fully achieved. The depolymerization and ring-closing reaction can be effectively carried out by continuously distilling the cyclic ethylenedioate produced under a pressure of 0.1 to 5 mmHg and a temperature of 230 to 300°C out of the reactor system. According to the method of the present invention, the residue after the reaction can be discharged by adding a compound such as mono- or polyethylene glycol, dissolving it by heating, but more rationally, the reaction residue can be discharged. If dicarboxylic acid or its ester and ethylene glycol, or dicarboxylic acid and ethylene oxide are newly charged without adding dicarboxylic acid or its ester, the polycondensation, depolymerization, and ring-closing reaction can be repeated again under the above-mentioned reaction conditions without substantially adding a depolymerization catalyst. However, if the amount of titanium compound used as a catalyst exceeds the upper limit shown above, this may be due to the high degree of crosslinking of the residue after the reaction. Even if we add a new one, we cannot obtain satisfactory results. By purifying the product fraction thus distilled, it is possible to obtain cyclic ethylenedioate having a purity of 99% or more and a desirable aroma. 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. Example 1 Dodecanedioic acid 100% in a reactor equipped with distillation equipment
g, 54 g of ethylene glycol and 0.1 g of titanium tetrabutoxide at 180-220°C under normal pressure while stirring.
Dehydrate by heating for 2 hours, then at 20-15 mmHg.
Most of the ethylene glycol was distilled off at 120-190°C for 2 hours, and then heated at 210-190°C at 3 mmHg.
A small amount of remaining ethylene glycol was distilled off at 220°C for 1 hour to produce polyethylene dodecanedioate. Then, when the degree of vacuum was set to 0.5 mmHg and the temperature was gradually raised, a depolymerization and ring closure reaction occurred from 240°C, and cyclic ethylene dodecanedioate was separated from the reactor system by distillation. Internal temperature up to 300℃
This operation was continued by heating for 10 hours to complete the reaction.
The yield of crude cyclic ethylene dodecanedioate is 94.6
g (85% yield from dodecanedioic acid), and the purity was 98%. This product was purified by distillation to obtain 85.0 g of cyclic ethylene dodecanedioate with a purity of 99.5% and a pleasant aroma. The yield from the raw material dodecanedioic acid was 77%. The residue in the reactor is 15 g. When 7 g of ethylene glycol was added to this residue and heated at 60-70°C for 30 minutes, it completely dissolved and could be discharged from the reactor very easily. Example 2 In the same reactor as Example 1, 100% of methyl brassylate was added.
Add 51 g of ethylene glycol and heat at 180 to 230°C under normal pressure for 3 hours with stirring to remove methanol, then heat at 130 to 200°C under pressure of 20 to 10 mmHg for 3 hours.
Most of the ethylene glycol is distilled off over time, and then under a pressure of 2 mmHg, the
A small amount of remaining ethylene glycol was removed over 1.5 hours at °C to produce polyethylene brasileate. Then, while stirring well, 0.1 g of titanium tetrabutoxide was added, the degree of vacuum was set to 0.5 mmHg, and the temperature was gradually raised. From 245° C., a depolymerization and ring closure reaction occurred, and cyclic ethylene brasileate began to distill out. This operation was continued for 10 hours until the internal temperature reached 300°C to complete the reaction. The yield of crude cyclic ethylene brasylate is
93g (84% yield from brassylic acid), purity 98.1%
It was hot. This product was further purified by distillation to obtain 83 g of cyclic ethylene brasileate with a purity of 99.5% and a pleasant aroma. The yield from the raw material brassylic acid was 75%. Also, the amount of residue in the reactor was 15 g. Add 7g of diethylene glycol to this residue and heat to 60-70℃.
After heating for 30 minutes, it completely dissolved and could be discharged from the reactor very easily. Example 3 100 g of sebacic acid and 0.1 g of titanium tetrabutoxide were placed in an autoclave, and 44 g of ethylene oxide was reacted at 135 to 145° C. for 1 hour. Put this reaction solution into the same reactor as in Example 1 and apply 20 to 15 mmHg.
Most of the ethylene glycol is distilled out at 140-190℃ for 2 hours under a pressure of 1-2 hours.
Polyethylene sebacate was produced by removing a small amount of remaining ethylene glycol over a period of 1.5 hours at 200-220°C under a pressure of mmHg. Then, while stirring, the degree of vacuum was set to 0.5 mmHg and the temperature was gradually raised.
Depolymerization and ring closure reactions occurred at 240°C, and cyclic ethylene sebacate began to distill out. The depolymerization reaction was carried out until the internal temperature reached 300°C, and the reaction was completed. The yield of crude cyclic ethylene sebacate was 91.5 g (81% yield from sebacic acid) with a purity of 98.3%. This product was further purified by distillation to obtain 82 g of cyclic ethylene sebacate (yield 73% based on the raw material sebacic acid) having a purity of 99.4% and a pleasant aroma. In addition, the residue containing unreacted polymer in the reactor is
Since the amount was 17 g, 8 g of ethylene glycol was added to this residue and heated to 60 to 70 DEG C., completely dissolving it and allowing it to be discharged from the reactor very easily. Example 4 Dodecanedioic acid 100g, ethylene glycol 54g
and 0.1 g of titanium tetrabutoxide were polycondensed and then depolymerized in the same manner as in Example 1 to distill off cyclic ethylenedioate. The residue in the reactor was 15
Then, 100 g of dodecanedioic acid and 54 g of ethylene glycol were added to g and polycondensed in the same manner as in Example 1 to produce polyethylene dodecanedioate. Then, when the degree of vacuum was set to 0.5 mmHg and the temperature was gradually raised, a depolymerization and ring closure reaction occurred from 240°C. Internal temperature 300
The depolymerization and ring closure reaction was carried out for 12 hours at ℃ to complete the reaction. The yield of crude cyclic ethylene dodecanedioate was 101 g, and the purity was 98.1%. 90.5 g of cyclic ethylene dodecanedioate with a purity of 99.4% and a pleasant aroma obtained by further distilling and refining this product.
I got it. The residue in the reactor was 23 g. When 11 g of ethylene glycol was added to this and heated to 60-70°C for 30 minutes, it completely dissolved and could be discharged extremely easily. Comparative example 1 Dodecanedioic acid 100g, ethylene glycol 54g
Polycondensation was carried out in the same manner as in Example 1 using 7.0 g of titanium tetrabutoxide and depolymerization ring-closing reaction was started, but in parallel with the generation of cyclic ethylene dodecanedioate, the viscosity of polyethylene dodecanedioate increased extremely. However, gelation finally begins, and 2
After some time, stirring became impossible. The yield of cyclic dodecanedioate at this point was 89.0g (yield 80% based on dodecanedioic acid), and although this product was purified by distillation, the purity was only 96.0%, and the yield was low at 77%. Summer. On the other hand, there was 20g of residue in the depolymerization reactor, so 100g of dodecanedioic acid and 54g of ethylene glycol were added thereto, and polycondensation, depolymerization, and ring-closing reactions were performed again in the same manner as in Example 1, but cyclic ethylene Stirring became impossible 1.2 hours after dodecanedioate was generated, and at that point there was only 33 g of crude cyclic ethylene dodecanedioate, and the yield was extremely low at 25%. Comparative example 2 Dodecanedioic acid 100g, ethylene glycol 54g
Polycondensation was carried out in the same manner as in Example 1 using 7.0 g of dibutoxytitanium dichloride, and then a depolymerization ring-closing reaction was started. The temperature rose, and gelation finally began, and stirring became impossible after 2.5 hours. The yield of dodecanedioate at this point was 88.3g (79% yield based on dodecanedioic acid), and this product was purified by distillation, but the purity was only 95.4% and the yield was low at 75%. Summer. On the other hand, since 22 g of residue remained in the depolymerization reactor, 100 g of dodecanedioic acid and 54 g of ethylene glycol were added thereto, and polycondensation, depolymerization, and ring-closing reactions were performed again in the same manner as in Example 1, but cyclic ethylene Stirring became impossible 1.1 hours after dodecanedioate was generated, and at that point there was only 31 g of crude cyclic ethylene dodecanedioate, and the yield was extremely low at 24%. Examples 5 to 9 Dodecanedioic acid and ethylene glycol (2 moles were used per 1 mole of dodecanedioic acid) were dehydrated by heating at 180 to 220°C for 3 hours under normal pressure while stirring,
Next, most of the ethylene glycol was distilled off at 120-190°C under a pressure of 20-10 mmHg for 3 hours, and then at 200-230°C under a pressure of 3 mmHg for 1.5 hours.
The remaining small amount of ethylene glycol was distilled off over time to produce polyethylene dodecanedioate. 100g of this polymer was charged in each case into the same reactor as in Example 1, 0.1g of the titanium compound shown in Table 1 was added, and depolymerization and ring closure were carried out under the conditions shown in the same table, resulting in the results shown in the table. I got it. The obtained crude cyclic ethylene dodecanedioate was purified by distillation to obtain cyclic ethylene dodecanedioate having a purity of 99.2% or more and a favorable aroma. Further, all the residues were easily completely dissolved by adding half of the weight of ethylene glycol and heating. In addition, Bu in Table 1 represents n-butyl.

[Table] Example 11 and Comparative Example 3 In the method described in Example 1, the amount of titanium tetrabutoxide used as a catalyst was varied to effect depolymerization and cyclization, and the results are shown in Table 2.

[Table] On the other hand, after each reaction, 7 g of ethylene glycol was added to the reactor and heated to 60 to 70°C for 30 minutes.
In each case, it was completely dissolved and could be discharged from the reactor very easily, but in each of the comparative examples, it was not completely decomposed under the same conditions, and therefore only a part of the residue was ethylene. It did not dissolve in the glycol, and the undissolved portion adhered to the reactor wall.

Claims (1)

[Claims] 1 The following general formula () ROOC (CH ₂ ) l COOR ... () (In the formula, l is a positive integer from 6 to 14, and R represents either a hydrogen atom or a lower alkyl group) Aliphatic dicarboxylic acid or its ester represented by ethylene glycol, or the general formula ()
An aliphatic dicarboxylic acid represented by the formula and ethylene oxide are polymerized to form a linear polyester, and this polyester is depolymerized to form a (wherein l represents a positive integer of 6 to 14), titanium trichloride or the following general formula () Ti ( OBu) m (OH) n Represents a positive integer of ~4. However, m + n + q = 4, one of m, n, and q is always 0, and if m is 0, n is 0 and q is 4.) A method for producing cyclic ethylenedioate, which comprises adding a titanium compound of 0.01% by weight or more and less than 0.1% by weight based on the polyester. 2. The manufacturing method according to claim 1, wherein titanium trichloride or a titanium compound represented by the general formula () is added during the polycondensation reaction of the aliphatic dicarboxylic acid and ethylene oxide. 3. Claim 1, characterized in that titanium trichloride or a titanium compound represented by the general formula () is added during depolymerization of the linear polyester.
Manufacturing method described in section.