JPS638971B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyether glycol, and more particularly to a polyether glycol containing oxytetramethylene groups as a main component, which has a relatively low molecular weight and high functionality and is useful as a raw material for polyurethane, elastic polyester, elastic polyamide, etc. This invention relates to a novel method for efficiently and easily manufacturing. Polytetramethylene glycol (hereinafter abbreviated as PTMG) is produced by polymerizing tetrahydrofuran or a mixture of tetrahydrofuran and other cyclic ethers copolymerizable with it in the presence of a ring-opening polymerization catalyst, and then hydrolyzing the polymerization reaction product. It is well known to produce polyether glycols containing oxytetramethylene groups as main components (hereinafter collectively referred to as PTMG-based polyether glycols including PTMG). thus obtained
In recent years, PTMG-based polyether glycol has gained attention in industrial importance because it provides materials with excellent physical properties such as mechanical properties and hydrolysis resistance when used as a raw material for polyurethane, elastic polyester, elastic polyamide, etc. It has come to be used in a wide variety of applications. The molecules used for these purposes usually have a relatively low number average molecular weight of about 500 to 5,000, and have hydroxyl groups at both ends of the molecule, in other words, have a high degree of functionality (2 closeness) is important. Various types of catalysts for ring-opening polymerization of tetrahydrofuran are known, but there are relatively few catalysts that can easily yield PTMG-based polyether glycols that have a relatively low molecular weight and have hydroxyl groups at both ends. It is already known to use fuming sulfuric acid or fluorosulfuric acid as such a ring-opening polymerization catalyst. (For example, Japanese Patent Publication No. 48-25438, Japanese Patent Publication No. 49-28917, Japanese Patent Publication No. 45-
3104). According to methods using catalysts mainly composed of these strongly acidic protonic acids, the number average molecular weight can be reduced.
Polymerization reaction products of about 1000 to 3000 can be easily produced, and both terminal hydroxyl groups can be easily removed by hydrolysis under acidic conditions after polymerization.
PTMG polyether glycol can be obtained. However, methods using these catalysts require a relatively large amount of catalyst in order to obtain a reasonable conversion rate in industrial implementation, and therefore require large-scale catalyst storage and handling equipment. There is a problem in that a large amount of acid is discharged as waste, and the treatment of this requires a lot of labor and cost. The need for such a large amount of catalyst is due to the low catalytic efficiency of these catalysts and the fact that the added catalyst is not fully utilized. It is desired to develop a method that can reduce the amount used. In addition, since these catalysts are strongly protic acids, they release a large amount of heat of mixing when they come into contact with tetrahydrofuran, etc., making it difficult to control the reaction temperature and causing problems such as coloring and decomposition of the polymerization reaction product. Another problem is that it tends to cause undesirable phenomena. In order to avoid these undesirable phenomena, polymerization can be carried out at a low temperature below 0°C, but at low temperatures the polymerization rate decreases and the reaction takes a long time, and the molecular weight of the PTMG polyether glycol is 1000°C. In the above case, at high conversion rates, the entire polymerization reaction system solidifies and loses fluidity, making operations such as stirring and transfer impossible. In addition, polymerization at such low temperatures tends to produce relatively high molecular weight polymerization reaction products;
It is extremely difficult to produce PTMG polyether glycol with a molecular weight of 1000 or less. In view of these circumstances, the present inventors have conducted various studies on the production method of PTMG-based polyether glycol, and have found that it is possible to significantly increase the catalytic efficiency, and at the same time prevent coloring of the polymerization reaction product and solidification of the polymerization system. The present invention was achieved by discovering a new method for producing PTMG polyether glycol at a high conversion rate. The first object of the present invention is to significantly increase catalyst efficiency when producing PTMG-based polyether glycol as a ring-opening polymerization catalyst for fuming sulfuric acid or fluorosulfuric acid, and to improve The object of the present invention is to provide a method for efficiently producing about 3000 PTMG polyether glycols. Here, the catalyst efficiency is defined as the ratio of the number of moles of PTMG polyether glycol molecules to the number of moles of the catalyst used during polymerization, and the calculation formula is shown in Examples below. The second objective is to provide a method for easily producing PTMG polyether glycol without causing undesirable phenomena such as coloring of the polymerization reaction product or solidification of the polymerization system at high conversion rates. . According to the present invention, tetrahydrofuran or a mixture of tetrahydrofuran and other cyclic ethers copolymerizable with it is polymerized in the presence of a ring-opening polymerization catalyst containing oleum and/or fluorosulfuric acid as a main component, and then a polymerization reaction product is obtained. (1) In the first step of the polymerization reaction, a monomer such as tetrahydrofuran and a ring-opening polymerization catalyst are brought into contact at a temperature in the range of -30°C to 10°C. , the above monomer is polymerized, and (2) then, when the conversion rate of the monomer to the polymer reaches 5% or more, the reaction temperature is set in the range of 0°C to 40°C, and the first step Provided is a method for producing polyether glycol, characterized in that the polymerization reaction is continued at a temperature that is at least 10° C. higher than the reaction temperature. In the method of the present invention, the catalyst efficiency can be significantly increased by carrying out the polymerization reaction of tetrahydrofuran etc. in two specific stages,
Not only can the amount of catalyst used (unit consumption) be reduced, reducing catalyst costs, but also the amount of waste acid produced during the manufacturing process can be reduced, and the burden required for its treatment can be reduced. Furthermore, compared to conventionally known methods, the method of the present invention does not involve coloring of the polymerization reaction product and solidification of the polymerization system at high conversion rates.
PTMG polyether glycol having a number average molecular weight of about 500 to 5000, which is most useful industrially, can be produced very easily. As described above, the method of the present invention has many advantages and therefore has extremely high industrial utility value. In particular, when using a catalyst containing fuming sulfuric acid as a main component, conventional methods have low catalytic efficiency and tend to cause coloring of the polymerization reaction product, so polymerization must be carried out at low temperatures. However, there was a problem that solidification of the polymerization reaction system was likely to occur at high conversion rates. For this reason, the method of the present invention is particularly useful when carrying out polymerization using a catalyst containing fuming sulfuric acid as a main component. Next, the present invention will be explained in more detail. In the method of the present invention, contact between a monomer such as tetrahydrofuran and a catalyst and a polymerization reaction are first carried out at a low temperature (first stage), and then the temperature is raised under specific conditions to continue polymerization (second stage). This is very important. In the first stage, the reaction temperature is -
It is set in the range of 30°C to 10°C. If the temperature in the first stage exceeds 10°C, there will be little improvement in catalyst efficiency, and the reaction will be difficult to control due to the heat generated during mixing of the monomer and catalyst, resulting in coloration and decomposition of the polymerization reaction product. becomes more likely to occur. On the other hand, if the temperature in the first stage is lower than -30 DEG C., it is not preferred from an industrial point of view because not only will a cooling facility with a large capacity be required, but the polymerization rate will become very slow and productivity will decrease. In order to achieve a particularly significant improvement in catalyst efficiency, the temperature in the first stage is preferably -30°C to 0°C. Next, in the second step, when the conversion rate of monomer to polymer reaches 5% or more, the reaction temperature is increased from 0°C to
The polymerization reaction is continued by raising the temperature to a temperature in the range of 40°C and at least 10°C higher than the first stage reaction temperature. When the conversion rate at the end of the first stage is less than 5%, it is unsuitable because a significant improvement in catalyst efficiency cannot be obtained. In view of the magnitude of the effect of improving catalyst efficiency, the conversion rate at the end of the first stage is preferably 10% or more. On the other hand, the upper limit of the conversion rate at the end of the first stage is
Although it cannot be determined unambiguously because it varies depending on the ratio of monomers and catalyst used and the molecular weight of the PTMG polyether glycol produced, in general, if the conversion rate becomes too high, the catalyst efficiency will be improved. is small, and in the case of a high molecular weight substance, the viscosity of the polymerization reaction system increases and furthermore, the entire system becomes solid, so these points are taken into consideration when setting. Considering both the magnitude of the catalyst efficiency improvement effect and operability, the conversion rate at the end of the first stage should be set as the target.
The following range is preferable depending on the number average molecular weight of the PTMG polyether glycol.

[Table] When the reaction temperature in the second stage is less than 0°C, there is almost no improvement in catalyst efficiency, and the number average molecular weight
It becomes extremely difficult to produce PTMG polyether glycol with a molecular weight of 1000 or less. Furthermore, if the reaction temperature in the second stage exceeds 40℃, the final conversion rate will decrease due to the influence of the chemical equilibrium of the polymerization reaction, the catalyst efficiency will decrease, and the burden of recovering and purifying unreacted monomers will increase, which is disadvantageous. In addition, coloration and decomposition of the polymerization reaction product occur. Also, the difference from the first stage polymerization temperature is 10
When the temperature is below ℃, almost no improvement in catalyst efficiency is observed. In view of the magnitude of the effect of improving catalyst efficiency and operability, the reaction temperature in the second stage is preferably 10°C to 40°C, with a difference of at least 15°C from the reaction temperature in the first stage. The polymerization time in the second stage varies depending on the ratio of monomers and catalyst used, reaction temperature, etc., and is not particularly limited, but is usually 1 to 5
About an hour is preferable. A suitable monomer for use in the process of the invention is tetrahydrofuran or mixtures thereof with other cyclic ethers copolymerizable with it. Specific examples of copolymerizable cyclic ethers include ethylene oxide, propylene oxide, three-membered ring ethers such as epichlorohydrin, oxacyclobutane,
3,3-dimethyloxacyclobutane, 3,3-
Examples include four-membered ring ethers such as bis(chloromethyl)oxacyclobutane, five-membered ring ethers such as 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, and 2,5-dihydrofuran, tetrahydropyran, and oxacycloheptane. When obtaining a polyether glycol containing an oxytetramethylene group as a main component according to the present invention, the amount of the cyclic ether copolymerizable with tetrahydrofuran is usually 100 parts by weight or less per 100 parts by weight of tetrahydrofuran. Preferably it is 50 parts by weight or less. In the method of the present invention, a catalyst containing fuming sulfuric acid and/or fluorosulfuric acid as a main component is used as a ring-opening polymerization catalyst. Normally used as fuming sulfuric acid
Suitably, the free SO ₃ concentration used in the production of PTMG-based polyether glycols is about 40% by weight or less, preferably 20% to 35% by weight. Although fuming sulfuric acid can be used alone,
If necessary, a suitable co-catalyst may be present in order to increase the polymerization rate or control the molecular weight. As the cocatalyst, known ones such as perchloric acid, perchlorate, metal fluorides, metal borofluorides, or aromatic compounds can be used.
Metal borofluorides, particularly sodium borofluoride and potassium borofluoride, are preferred from the viewpoint of ease of acquisition and handling and effectiveness. Fluorosulfuric acid is usually used alone as a ring-opening polymerization catalyst, but
Depending on the case, for example, an anhydride of a chain carboxylic acid may be used together. In carrying out the method of the present invention, the amount of ring-opening polymerization catalyst used is not particularly limited. Examples of commonly used ranges include 10 to 40 parts by weight for 100 parts by weight of monomer in the case of oleum;
Further, when a co-catalyst is used, the amount used is 0.05 to 20 parts by weight per 100 parts by weight of oleum. In the case of fluorosulfuric acid, the amount to be used is 1 to 20 parts by weight per 100 parts by weight of the monomer, and if necessary, 5 to 400 parts by weight of chain carboxylic acid anhydride etc. to 100 parts by weight of fluorosulfuric acid. Use in combination in approximately parts by weight. The amount of these ring-opening polymerization catalysts to be used is appropriately selected depending on the required molecular weight of PTMG, etc. The ring-opening polymerization reaction method is not particularly limited, and can be carried out in a batch reaction, a continuous reaction, etc. When carried out in a batch reaction, the catalyst is heated at an appropriate rate to facilitate the removal of the heat of mixing. It is preferable to stir the polymerization system while continuously adding it to the monomer. In the method of the present invention, tetrahydrofuran or the like can be polymerized in the presence of an inert solvent such as cyclohexane, dichloroethane, or dichloromethane, but it is preferable to carry out the polymerization without using a solvent unless particularly necessary. In the method of the present invention, after polymerizing a monomer such as tetrahydrofuran as described above, the polymerization reaction product is hydrolyzed, and the hydrolysis reaction is carried out under acidic conditions. For example, after completing the polymerization, add water in an amount such that the sulfuric acid concentration after dilution is 5% to 40% by weight, and then heat the mixture under reflux at a temperature of 80°C to 120°C for about 1 to 10 hours. Can be done. The hydrolysis reaction may be carried out immediately after the completion of the polymerization, or it may be carried out after the polymerization has been stopped in advance with a small amount of water and unreacted monomers and solvents have been recovered by methods such as distillation or stripping. Furthermore, it is also possible to distill and recover unreacted monomers and solvents simultaneously with the hydrolysis reaction. The method for recovering PTMG polyether glycol from the reaction mixture after hydrolysis is not particularly limited, and for example, after hydrolysis, it can be left to cool,
This can be done by separating the PTMG polyether glycol as an oil layer, removing the aqueous layer, neutralizing the acid content in the oil layer with a solid alkali, separating the solid, and removing volatile components under reduced pressure. can. In the above operations, in order to facilitate the recovery of PTMG polyether glycol,
It is possible to add a solvent that dissolves the PTMG polyether glycol and is immiscible with water, such as benzene, toluene, chloroform, n-butanol, and the like. To prevent the PTMG polyether glycol thus obtained from deteriorating during storage, measures such as storing it in an inert gas such as nitrogen or adding a small amount of antioxidants such as hindered phenols to stabilize it are taken. It is preferable to take measures. According to the method of the present invention, a PTMG polyether glycol having a molecular weight of about 500 to 5000 and a high functionality is useful as a raw material for polyurethane, elastic polyester, elastic polyamide, etc. suitable for applications such as rolls, belts, and solid tires. can be manufactured efficiently. The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded.
In addition, in the following examples, all number average molecular weights were measured using a vapor pressure osmometer, and the hydroxyl value (equivalent to OH groups in 1 g of polymer)
All values (mg of KOH) were measured according to the method of JIS-K1557-1970. Example 1 A four-necked separable flask with an internal volume of 1.2 equipped with a Teflon stirrer, a dropping funnel, a thermometer, and a three-way pot was vacuum dried, replaced with nitrogen gas, and dehydrated with a molecular sieve. Moisture content
Prepare 500g of 80ppm tetrahydrofuran-
Cooled to 20°C. Next, add fuming sulfuric acid (hereinafter referred to as 25%) with a free SO ₃ concentration of 25% by weight from the dropping funnel while stirring.
% fuming sulfuric acid) was added dropwise over 40 minutes.
During the dropwise addition, the reaction mixture was cooled to maintain a temperature of -20°C±2°C. After the dropwise addition was completed, the reaction was allowed to proceed for 2 hours with stirring at -20°C, and then a portion of the reaction solution was sampled and the amount of unreacted tetrahydrofuran was measured using a gas chromatograph to determine the conversion rate, which was 32%. Then the temperature of the reaction mixture was increased to 10°C.
The temperature was raised to , and the reaction was continued with stirring for an additional 2 hours. The reaction mixture was colorless throughout the reaction, and the reaction system remained homogeneous and liquid without solidifying. Next, the conversion rate was determined in the same manner as above, and it was found that 58
It was %. After the reaction was completed, 420 g of ion-exchanged water was added while stirring to stop the reaction, and the reaction solution was transferred to a three-neck separable flask with an internal volume of 2 equipped with a Teflon stirring device and distillation device, and placed in an oil bath at 95°C while stirring. The mixture was heated for 2 hours to hydrolyze the terminal end of the polymerization reaction product, and at the same time, unreacted tetrahydrofuran was distilled and recovered. After hydrolysis, stirring was stopped, and the reaction mixture was left to cool at room temperature. The separated aqueous layer was extracted. To the remaining oil layer, 600 g of toluene and 3 g of calcium hydroxide were added, and the mixture was stirred at room temperature for 1 hour. Then, a portion of the toluene was distilled off along with the remaining water using a rotary evaporator at about 60° C. under reduced pressure. The solid is then passed through a filter, and the volatile components are completely distilled off again using a rotary evaporator to form a colorless solid.
Got PTMG. The number average molecular weight of this substance is 1000,
The hydroxyl value was 112, and the functionality calculated from these values was 2.0. Further, when the catalyst efficiency α was determined, it was 0.93. Note that α is calculated using the following equation (1). α=[Number of moles of PTMG polyether glycol molecules]/
[Number of moles of SO ₃ in the fuming sulfuric acid used] = [Amount of monomer used] x [Conversion rate] x 80 / [Amount of fuming sulfuric acid used] x 25 x [Number average molecular weight of PTMG polyether glycol]... (1) Example 2 Using the same reaction apparatus as in Example 1, 0.75 g of sodium borofluoride dissolved in 105 g of 25% oleum was added dropwise to 500 g of tetrahydrofuran over 40 minutes while keeping the temperature at -10°C. After the dropwise addition was completed, the reaction was further carried out at -10°C for 1 hour. The conversion rate of tetrahydrofuran at this time was 40%. Then, the temperature of the reaction mixture was raised to 30°C, and the reaction was continued for an additional 2 hours. The conversion rate after the completion of the reaction was 55%. No solidification or coloring of the reaction system was observed throughout the reaction. The polymerization reaction mixture was then treated in the same manner as in Example 1 to obtain colorless PTMG. The analysis results and catalyst efficiency α of this product were as shown in Table 1. Example 3 Using the same reaction apparatus as in Example 1, 500 g of tetrahydrofuran was mixed with 25% oleum while keeping it at -20°C.
150 g was added dropwise over 1 hour, and after the addition was completed, the reaction was further carried out at -20°C for 10 minutes. The conversion rate at this time is
It was 14%. Then, the reaction temperature was raised to 30℃ and 1
Allowed time to react. The conversion rate after the completion of the reaction was 47%. There was no solidification or coloration of the reaction system throughout the reaction. Next, while stirring the reaction mixture well, add 180 g of ion-exchanged water to stop the reaction, and then
145 g of 45% sodium hydroxide solution was added to neutralize a portion of the sulfuric acid. After replacing the dropping funnel with a distillation apparatus, the mixture was heated in an oil bath at 95° C. for 2 hours to hydrolyze the terminal end of the polymerization reaction product and at the same time distill off unreacted tetrahydrofuran. After the reaction, stirring was stopped and the mixture was allowed to cool to room temperature. The separated aqueous phase was extracted, 180 g of ion-exchanged water was added to the oil layer, and the mixture was heated in an oil bath at 95° C. for 2 hours while stirring again. After the reaction, the mixture was left to cool at room temperature, the separated aqueous layer was extracted, and the oil layer was treated in the same manner as in Example 1 to obtain colorless liquid PTMG. The analysis results and catalyst efficiency α of this product were as shown in Table 1. Example 4 Using a four-neck separable flask with an internal volume of 600 ml prepared in the same manner as in Example 1, 0.75 g of sodium borofluoride was dissolved in 27.5 g of 25% oleum while maintaining 250 g of tetrahydrofuran at -10°C. The solution was added dropwise over 30 minutes, and then -
The reaction was carried out at 10°C for 2 hours. Then the reaction temperature was increased to 30℃
The temperature was increased to 2 hours and the reaction was carried out for 2 hours. The conversion rate at the end of the first stage was 37%, and the final conversion rate was 59%. No solidification or coloration of the reaction system was observed throughout the reaction. After the reaction was completed, 195 g of ion-exchanged water was added to the mixture while stirring to stop the reaction, and the same treatment as in Example 1 was carried out to obtain colorless semi-solid PTMG. The analysis results and catalyst efficiency α of this product were as shown in Table 1. Example 5 Using the same reactor as in Example 4, 25% oleum was added to 250 g of tetrahydrofuran while keeping it at -20°C.
A solution of 0.75 g of sodium borofluoride dissolved in 27.5 g was added dropwise for 30 minutes, and after the addition was complete, -
The reaction was carried out at 20°C for 2 hours. Then the reaction temperature was increased to 10℃
The temperature was raised to 1, and the mixture was allowed to react for 2 hours. The conversion rate and final conversion rate at the end of the first stage were 19% and 69, respectively.
%, and no solidification or coloring of the reaction system was observed throughout the reaction. After the reaction was completed, the same treatment as in Example 4 was carried out to obtain colorless semi-solid PTMG.
The analysis results and catalyst efficiency α of this product were as shown in Table 1. Example 6 Using the same reaction apparatus as in Example 1, 0.82 g of potassium borofluoride dissolved in 105 g of 25% oleum was added dropwise to 500 g of tetrahydrofuran over 40 minutes while keeping the temperature at -10°C. After the dropwise addition was completed, the reaction was further carried out at -10°C for 1 hour. The conversion rate of tetrahydrofuran at this time was 38%. Then, the temperature of the reaction mixture was raised to 10°C, and the reaction was continued for an additional 2 hours. The conversion rate after the completion of the reaction was 60%. No solidification or coloring of the reaction system was observed throughout the reaction. The polymerization reaction mixture was then treated in the same manner as in Example 1 to obtain colorless PTMG. The analysis results and catalyst efficiency α of this product were as shown in Table 1. Comparative Example 1 In the experiment of Example 1, the temperature during dropping of fuming sulfuric acid was set to 10°C, and after the completion of dropping, the temperature was set to 4°C at the same temperature.
The reaction was carried out under the same conditions except for a longer reaction time. The obtained PTMG was a slightly yellow liquid, and the analysis results and catalytic efficiency α were as shown in Table 1. Comparing the results of this comparative example with the results of Example 1, it is clear that the method of the present invention is superior. Comparative Example 2 In the experiment of Example 1, the reaction was carried out under the same conditions except that the reaction was further carried out at -20°C for 4 hours without raising the temperature after the first stage reaction was completed. After the reaction was completed, the polymerization reaction mixture was wax-like and stirring was almost impossible.
The final conversion rate was 45%, and the analysis results of colorless PTMG recovered in the same manner as in Example 1 and the catalyst efficiency α were as shown in Table 1. Comparative Example 3 Using the same reaction apparatus as in Example 1, 150 g of 25% oleum was added dropwise over 1 hour to 500 g of tetrahydrofuran while keeping the temperature at 0°C, and the reaction was further carried out at 0°C for 2 hours. The reaction system remained liquid even after the reaction was completed, and the conversion rate was 68%. After the reaction was completed, the same operation as in Example 1 was carried out except that 630 g of ion-exchanged water was added to obtain colorless PTMG. obtained
The PTMG analysis results and catalyst efficiency α are shown in Table 1, and it can be seen that the catalyst utilization efficiency is significantly lower than in the method of the present invention. In addition, in order to obtain PTMG with a molecular weight of about 650 using this method, experiments were conducted by varying the amount of oleum used, SO ₃ concentration, dropping rate of oleum, and polymerization time after dropping, but in all cases PTMG had a molecular weight of 850 or more, and it was not possible to obtain PTMG with a molecular weight of about 650. Comparative Example 4 In the experiment of Example 3, after the first stage was completed, the reaction temperature was kept at -20°C for 3 more times.
The experiment was carried out under the same conditions except that the reaction was continued for an hour. Even after the reaction was completed, some of the reaction system had begun to solidify and was cloudy white. The final conversion rate is 58%,
The obtained PTMG was colorless, and the analysis results and catalytic efficiency α were as shown in Table 1. Comparative Example 5 In the experiment of Example 3, the temperature at the time of dropping oleum was set at 30°C, and after the completion of dropping, the temperature was set at 20°C at the same temperature.
The experiment was conducted under the same conditions except for the reaction time. During the dropping of the fuming sulfuric acid, it was difficult to control the temperature of the reaction mixture due to heat generation, and the reaction mixture turned yellow from about 5 minutes after the start of the dropping, and turned brown by the end of the dropping. The obtained PTMG was also colored brown, and the analysis results and catalytic efficiency α were as shown in Table 1. Comparative Example 6 Using the same reaction apparatus as in Example 4, 25% oleum was added to 250 g of tetrahydrofuran while keeping it at 0°C.
A mixture of 50g and 1.75g of sodium borofluoride
The mixture was added dropwise over a period of time, and the reaction was further carried out at the same temperature for 2 hours. The final conversion rate was 66%, and the reaction system had solidified into a waxy state. Colorless PTMG was obtained in the same manner as in Example 4, and the analysis results and catalytic efficiency α were as shown in Table 1. Comparative Example 7 In the experiment of Example 4, the reaction was continued at -10°C without increasing the temperature after the first stage reaction was completed. Approximately 5 hours after the completion of the dropwise addition, the reaction system solidified into a waxy state, and stirring became impossible. At this point, the reaction was stopped and the same procedure as in Example 4 was carried out.
PTMG was collected. The analysis results and catalyst efficiency α of this product are shown in Table 1. Comparative Example 8 The same experiment as in Example 4 was carried out except that fuming sulfuric acid was added dropwise while keeping the tetrahydrofuran at 30°C, and the reaction was continued for 4 hours at the same temperature. The final conversion rate is 30%,
The recovered PTMG had a light brown color. The analysis results and catalyst efficiency α of this product are shown in Table 1. Comparative Example 9 In the experiment of Example 5, the reaction time of the first stage was 30 minutes after the completion of dropping, and the reaction time of the second stage was 2.5 minutes.
The experiment was conducted under the same conditions except for the time.
The conversion rate at the end of the first stage and the final conversion rate are 1.5
% and 63%. The analysis results and catalytic efficiency α of this product are shown in Table 1, and the results show that when the conversion rate in the first stage does not reach 5%, almost no increase in catalytic efficiency is observed. Comparative Example 10 The experiment was conducted under the same conditions as in Example 1, except that the temperature during catalyst dropwise addition and the first stage reaction was 5°C. Analysis results of colorless PTMG obtained with final conversion rate of 46% and catalyst efficiency α
were as shown in Table 1. This result shows that when the difference in reaction temperature between the first stage and the second stage is less than 10°C, the catalyst efficiency hardly increases.

【table】

[Table] Example 7 Using the same reaction apparatus as in Example 4, 20 g of fluorosulfuric acid was added dropwise over 30 minutes to 250 g of tetrahydrofuran while keeping it at 0°C. After further reaction at 0°C for 1 hour, the reaction temperature was was raised to 20°C and reacted for 5 hours. The conversion rate at the end of the first stage and the final conversion rate were 18% and 72%, respectively, and there was no solidification or coloration of the reaction system throughout the polymerization.
After the reaction was completed, 135 g of ion-exchanged water was added to the mixture while stirring, and the same treatment as in Example 4 was carried out to recover colorless PTMG. The number average degree of polymerization of this product was 1880, the hydroxyl value was 60, and the functionality was 2.0. Further, the catalyst efficiency β was calculated using the following equation (2), and the result was 0.96. β = [Number of moles of PTMG polyether glycol molecules] /
[Number of moles of fluorosulfuric acid used] x 2 = [Amount of monomer used] x [Conversion rate] x 2 / [Amount of fluorosulfuric acid used] x [Number average molecular weight of PTMG polyether glycol]...(2) Implementation Example 8 225g of tetrahydrofuran and 3,
The experiment was carried out under the same conditions as in Example 4, except that a mixture of 25 g of 3-dimethyloxacyclobutane was used. The conversion rate at the end of the first stage was 40%, and the final conversion rate was 64%. No solidification or coloring of the reaction system was observed throughout the reaction. The number average molecular weight of the colorless liquid polyether glycol obtained is
2050, the hydroxyl value was 54, the functionality was 2.0, and the catalytic efficiency α was 0.91. Example 9 The experiment was carried out under the same conditions as in Example 7 except that the reaction temperature during the fluorosulfuric acid addition and in the first stage was 5° C., and the reaction time after the addition was 40 minutes. The conversion rate at the end of the first stage and the final conversion rate were 21% and 71%, respectively, and there was no solidification or coloring of the reaction system throughout the polymerization. The number average molecular weight of the obtained PTMG was 1900, the hydroxyl value was 59, the functionality was 2.0, and the catalytic efficiency β was 0.93.
It was hot. Comparative Example 11 In the experiment of Example 7, the reaction was continued at 0° C. for 5 hours without increasing the temperature even after the first stage reaction was completed.
The final conversion rate was 68%, and the reaction system was solidified after the reaction was completed. The same treatment as in Example 7 was performed to recover colorless PTMG. Its number average molecular weight is
2020, the hydroxyl value was 52, the functionality was 2.0, and the catalytic efficiency β was 0.84. Comparative Example 12 In the experiment of Example 7, fluorosulfuric acid was added while keeping tetrahydrofuran at 20°C, and after that, the reaction was continued for another 6 hours while keeping the same temperature, and then the same treatment as in Example 7 was carried out. colorless
Got PTMG. The final conversion rate was 67%, the number average molecular weight of the obtained PTMG was 1930, and the hydroxyl value was
58, functionality was 2.0 and catalytic efficiency β was 0.87.

Claims (1)

[Claims] 1 Polymerize tetrahydrofuran or a mixture with other cyclic ether copolymerizable with it in the presence of a ring-opening polymerization catalyst containing fuming sulfuric acid and/or fluorosulfuric acid as a main component, and then hydrolyze the polymerization reaction product. In producing polyether glycol (1) In the first step of the polymerization reaction, a monomer such as tetrahydrofuran and a ring-opening polymerization catalyst are heated at -30°C.
(2) Then, when the conversion rate of the monomer to the polymer reaches 5% or more, the reaction temperature is reduced to 0. ℃
A method for producing polyether glycol, characterized in that the polymerization reaction is continued at a temperature in the range of ~40°C and at least 10°C higher than the reaction temperature in the first stage.