JPS591293B2 - Polyoxytetramethylene glycol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyoxytetramethylene glycol (hereinafter referred to as P
The present invention relates to a method for producing TQ), and more specifically to improving a method for polymerizing tetrahydrofuran using fuming sulfuric acid as a catalyst.

Polyoxytetramethylene glycol is produced by ring-opening polymerization of tetrahydrofuran (hereinafter referred to as THF), and its polymerization catalysts include protonic acids, ion complexes, Lewis acids, Lewis acids, alkylene oxides, active halogen compounds, etc. A system that adds , etc. is effective,
Various catalyst systems have been studied so far. However, the above-mentioned catalysts include not only those with high activity but also those with low activity, and PTG obtained by polymerization methods using these catalysts ranges from low molecular weight substances with a molecular weight of several hundred to high molecular weight substances of tens of thousands or more. It even extends to merging. However, for applications such as polyurethane and polyether ester, which have been attracting attention in recent years, molecules with a molecular weight of about 1,000 to 3,000 are industrially important, and in order to produce such PTG, fluorosulfonic acid, fume Only polymerization catalysts based on protonic acids such as sulfuric acid and acetic anhydride-perchloric acid systems have been put into practical use. Among these, polymerization methods using fluorosulfonic acid and acetic anhydride monoperchloric acid as catalysts each have drawbacks, such as the use of a large amount of catalyst and high price, or the need for a large amount of acetic anhydride. . Furthermore, in the polymerization method using fuming sulfuric acid as a catalyst, the molecular weight of PTG remains at around 1000 even if the polymerization conditions are changed, which is a fatal flaw that prevents it from being applicable to a wide variety of purposes. In view of the above-mentioned circumstances, the present inventors have completed the present invention as a result of repeated searches for an effective industrial catalyst that corrects the drawbacks of conventional catalyst systems, particularly oleum-only systems.

That is, the present invention involves polymerizing THF using trifluoromethanesulfonic acid and fuming sulfuric acid as catalysts.
This is a method by which PTG having a molecular weight of 1,000 to 3,000 or more can be produced in high yield very easily.
The trifluoromethanesulfonic acid used in the present invention itself has catalytic activity, and a polymer can be obtained even if it is reacted alone with THF, but in order to produce PTG with a molecular weight of about 1000 to 3000, a large amount of trifluoromethane Requires sulfonic acid, resulting in high viscosity and high degree of polymerization in small amounts
G, and the yield is also low.

However, by coexisting a small amount of trifluoromethanesulfonic acid with fuming sulfuric acid, the defects of each single system were eliminated, the yield and molecular weight were increased compared to the case of using only fuming sulfuric acid, and the molecular weight of PTG could be adjusted arbitrarily. It has a soothing effect. In the present invention, the molecular weight of PTG changes by changing the polymerization temperature, time, and the amount and ratio of oleum and trifluoromethanesulfonic acid.
Molecular weight 1000 to 3000 by selecting appropriate conditions
Or more can be manufactured at will upon request.

In the present invention, the amount of trifluoromethanesulfonic acid used is approximately 0.1 to 5% by weight based on THF, and the fuming sulfuric acid used in combination with trifluoromethanesulfonic acid is carbonized by THF. It is preferable to have an SO3 concentration of about 40% or less, although it varies depending on the polymerization conditions and operating conditions.

The amount used varies widely depending on the SO3 concentration, but is generally in the range of 3 to 60% by weight relative to THF. If the polymerization temperature is raised, the reaction solution tends to be colored and the yield decreases, so the polymerization temperature is -40°C to +30°C, preferably -20°C.
It is preferable to add the catalyst and carry out the polymerization at a temperature of 0.degree. C. to +20.degree.

The catalyst can be added by adding trifluoromethanesulfonic acid and then fuming sulfuric acid dropwise to THF while stirring at a set temperature, or in the reverse order, or at the same time, or adding trifluoromethanesulfonic acid to fuming sulfuric acid in advance. A method is adopted in which a catalyst mixture solution prepared by dissolving the solution is dropped.

When dropping the catalyst, the reaction solution is cooled to control heat generation, and the dropwise addition is carried out over 30 minutes to 2 hours while maintaining the set temperature. After dropping, leave at the set temperature for 30 minutes to 15 hours, preferably 1 hour.
Continue polymerization for 10 to 10 hours. After the polymerization is completed, water is added to the reaction solution to stop the polymerization, and unreacted THF is distilled off by heating, followed by hydrolysis, aqueous layer separation, and water layer separation according to known methods.
PTG can be obtained through steps such as purification and drying of the THF polymer.

For example, after termination of polymerization, unreacted THF is distilled off by heating, followed by hydrolysis at 100° C. for about 2 hours.

The amount of water used for polymerization termination is determined by considering the hydrolysis conditions, and the sulfuric acid concentration in the sulfuric acid water in the reaction system is 10 to 25% by weight.
, preferably 10 to 15% by weight. After the hydrolysis is completed, the reaction solution is allowed to stand to separate into an organic layer consisting of a tetrahydrofuran polymer and an aqueous layer, and the aqueous layer is removed. To the remaining organic layer, add an organic solvent that dissolves PTG and is difficult to dissolve in water, such as benzene, toluene, n-butanol, IsO-butanol, di-isopropyl ether, etc., then add water, stir well, and leave to stand. Separate the layers and remove only the aqueous layer. After the solvent layer is purified by repeating such washing and separation or by other known methods, the solvent is distilled off and dried under reduced pressure, whereby pure PTG can be obtained in good yield. Next, the present invention will be explained in more detail with reference to Examples.

In the examples, unless otherwise specified, parts and percentages indicate parts by weight and percentages by weight, respectively. Example 1 Part of THFlOO was charged into a four-necked flask equipped with a stirrer, kept at -3°C to 0°C with external cooling while stirring, and 1.0 part of trifluoromethanesulfonic acid was added, followed by 13 parts of 30% fuming sulfuric acid.
．． Three parts were added dropwise over a total of 40 minutes.

After dropping the catalyst, a THF polymerization reaction was carried out at 0° C. for 5 hours, and then 80.5 parts of water was added to stop the polymerization. A distillation tube was attached and heated to distill off unreacted THF, and the tube was replaced with a reflux condenser and hydrolysis was carried out at 100° C. for 2 hours.
Cool to 70 to 80°C, leave to stand, separate and remove the aqueous layer, then add 50 parts of n-butanol and 25 parts of water to the organic layer, stir at about 80°C, leave to stand again to remove n-butanol. The layer was separated into an aqueous layer, and the aqueous layer was separated.

Next, 25 parts of water was added, stirred in the same manner at 80°C, left to stand, and the aqueous layer separated. After repeating the purification operation three times, n-butanol and remaining water in the organic layer were distilled off, and the remaining water was distilled off under reduced pressure. After drying, PTG77. 1 portion was obtained. The yield, molecular weight determined by 0H value measurement, and color measurement results were as follows.
Yield: 77.1% Molecular weight (M): 2040 Color (APHA): 30 Examples 2 to 7 The same procedure as in Example 1 was performed, except that a catalyst mixture of trifluoromethanesulfonic acid dissolved in fuming sulfuric acid was added dropwise to THF. THF was polymerized by changing the catalyst amount and quantitative ratio, and the results shown in Table 1 below were obtained.

Note that Table 1 also shows the results using fuming sulfuric acid alone without using trifluoromethanesulfonic acid as a control. From the results shown in Table 1, it is clear that the method of the present invention brings about a remarkable improvement in yield and an effect of increasing molecular weight.

Claims (1)

[Claims] 1. A method for producing polyoxytetramethylene glycol, which comprises polymerizing tetrahydrofuran using trifluoromethanesulfonic acid and fuming sulfuric acid as catalysts.