JP2546909B2 - Method for producing polyhydroxyalkane - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyhydroxyalkane having two or more hydroxy groups in one molecule.

(Problems to be Solved by Prior Art and Invention) 1,2-Dichloropropane (hereinafter, abbreviated as PDC) is produced as a large amount when propylene oxide is produced from propylene via chlorohydrin. In order to effectively utilize this PDC, PDC was reacted with chlorine at high temperature to induce tetrachlorethylene and carbon tetrachloride. Tetrachloroethylene was in great demand as a raw material for Freon 113, but in recent years it has been internationally agreed that the use of Freon 113 will be completely abolished by the 21st century due to ozone depletion in the stratosphere caused by Freon. It is clear that the demand for tetrachloroethylene, which is a raw material for the synthesis of CFC113, and PDC, which is a raw material for tetrachloroethylene, will drastically decrease in the future. Therefore, it became necessary to develop new applications for PDC.

According to British Patent No. 1553819, a method for obtaining propylene glycol (hereinafter abbreviated as PG) in 80% yield by heating PDC, water, sodium hydrogen carbonate and tributylhexadecylphosphonium bromide at 100 ° C. for 18 hours is disclosed. Has been presented. PG is widely used industrially as a polyester raw material or an antifreeze component. Therefore, it is significant to convert the by-product PDC to PG. However, the above-mentioned prior art has a problem that the yield is as high as 80%, but it is not sufficient yet.

(Means for Solving the Problems) Therefore, the inventors of the present invention, as a result of continuing diligent research to overcome the above problems, have found that polychloroalkanes can be added to an aqueous solution of an alkali metal salt or an alkaline earth metal salt at a specific rate. The present invention was completed by finding that polyhydroxyalkane was obtained in a high yield by supplying and hydrolyzing.

That is, the present invention provides the following general formula [I] (However, R is a hydrogen atom, an alkyl group or a chlorinated alkyl group.) The polychloroalkane represented by the formula (1) is an alkali metal or alkaline earth metal hydrogen carbonate or carbonate (hereinafter, simply referred to as “alkali metal salt or alkali metal salt”). Also referred to as "earth metal salt") in an aqueous solution of the following general formula [II] (However, R'is a hydrogen atom, an alkyl group, a chlorinated alkyl group or a hydroxyalkyl group.) In the method for producing a polyhydroxyalkane, a hydrogen carbonate or carbonate of an alkali metal or an alkaline earth metal is used. In the method for producing a polyhydroxyalkane, the polychloroalkane is supplied to the aqueous solution in an amount of 0.0001 parts by weight to 10 parts by weight per minute with respect to 100 parts by weight of water in the aqueous solution to hydrolyze. is there.

Hereinafter, the present invention will be described in more detail. The polychloroalkane in the present invention is a compound represented by the above general formula [I]. R may be hydrogen, an alkyl group or a chlorinated alkyl group, and is not particularly limited. Typical examples of the compound represented by the general formula [I] include 1,2-dichloroethylene, 1,2-dichloropropane, 1,
2,3-trichloropropane, 1,2-dichlorobutane, 1,2-
Examples include dichloropentane.

As the alkali metal salt or alkaline earth metal salt in the present invention, any known one can be used without limitation as long as it is a hydrogen carbonate or carbonate of an alkali metal or alkaline earth metal, but a saturated aqueous solution has weak alkalinity. The compounds shown are preferably used. Specific examples include hydrogen carbonates of alkali metals such as sodium hydrogen carbonate and potassium hydrogen carbonate, carbonates of alkaline earth metals such as calcium carbonate and magnesium carbonate, and the like. These alkali metal salts or alkaline earth metal salts are dissolved or further suspended in water and used in the hydrolysis reaction of the present invention. The aqueous solution in the present invention includes both the above-mentioned solution and suspension.

The amount of the alkali metal salt or the alkaline earth metal salt to be used for the polychloroalkane may be appropriately determined as necessary, but generally, the molar ratio to the total amount of polychloroalkane supplied is equal to 10 times the equivalent amount. Ranges are preferred.

The amount of water used with respect to the polychloroalkane is not particularly limited, but it is generally preferable that the amount is equal to or more than the total amount of polychloroalkane supplied in a molar ratio.

The supply rate of the polychloroalkane in the present invention is selected from the range of 0.0001 parts by weight to 10 parts by weight per minute with respect to 100 parts by weight of water in the aqueous solution of the alkali metal salt or alkaline earth metal salt. Particularly preferably 0.001 parts by weight
It is in the range of 3 parts by weight. If it is less than 0.0001 part by weight, the amount of polyhydroxyalkane produced per unit time is extremely low, which is not practical. At a rate exceeding 10 parts by weight, the reaction rate of the dechlorination reaction of polychloroalkane becomes faster and the selectivity of polyhydroxyalkane decreases. The supply rate of polychloroalkane can be changed according to the reaction temperature. That is, in order to obtain a polyhydroxyalkane in a high yield, the feed rate needs to be slow when the reaction temperature is low, and the feed rate may be fast when the reaction temperature is high. Therefore, the supply rate of the polychloroalkane may be determined within the above range depending on the reaction temperature.

In general, the reaction temperature is preferably in the range of 130 to 300 ° C. in order to speed up the hydrolysis reaction and prevent a decrease in the yield of the target polyhydroxyalkane due to a side reaction.

The reaction system may be a batch system, a semi-batch system or a continuous system, but the semi-batch system and the continuous system are particularly preferred. That is, a reactor is charged with an aqueous solution of the alcal metal salt or alkaline earth metal salt, and a semi-batch method for continuously or intermittently supplying polychloroalkane at a predetermined temperature, or the above alkali metal salt or alkaline earth metal salt. A continuous system in which an aqueous solution is charged into a reactor, polychloroalkane and the aqueous solution are continuously or intermittently supplied at a predetermined temperature and a reaction solution is continuously or intermittently withdrawn is preferably used. In the present invention, it is preferable to stir during the reaction. In the present invention, when a carbonate or hydrogen carbonate is used as the alkali metal salt or alkaline earth metal salt, carbon dioxide gas is generated during the reaction. Therefore, this carbon dioxide gas is collected and bubbled in the reaction solution. By doing so, stirring can be performed.

The method for isolating and purifying the polyhydroxyalkane, which is the desired product, from the reaction system is not particularly limited, and known methods such as filtration and distillation can be employed.

By the above method, the polyhydroxyalkane represented by the general formula [II] can be obtained.

(Effect) By setting the supply rate of the polychloroalkane to a specific range by the method of the present invention, the target polyhydroxyalkane can be obtained in high yield.

(Examples) Examples are given to more specifically describe the present invention, but the present invention is not limited to these examples.

Example 1 In an autoclave having an inner volume of 300 ml, 60 g of calcium carbonate
And 150 g of water were charged and the temperature was raised to 230 ° C. 0.030 g / min of PDC (1,2-dichloropropane) at the above temperature while stirring
Water was continuously fed at a rate of 100 g for 11.5 hours. After feeding, the mixture was stirred for 30 minutes at the above temperature and then rapidly cooled to room temperature. As a result of analyzing the reaction solution by gas chromatography, PG (propylene glycol) was obtained in a yield of 95%.

Example 2 The procedure of Example 1 was repeated except that 1,2-dichloroethane was used instead of PDC as one of the starting materials.
As a result, 1,2-dihydroxyethane was obtained in a yield of 94%.

Example 3 In Example 1, PDC, which is one of the raw materials, was replaced with 1,2,3-trichloropropane, and the feed rate was 0.010 g /
The same procedure as in Example 1 was carried out except that 100 g of minute water was used. As a result, 90% of 1,2,3-trihydroxypropane
It was obtained with a yield of.

Examples 4 to 6 The procedure of Example 1 was repeated, except that the salts listed in Table 1 were used instead of calcium carbonate in the amounts listed in Table 1. Table 1 shows the yields of PG produced when the respective salts were used.

Examples 7 to 9 The procedure of Example 1 was repeated, except that the reaction temperature and the feed rate of PDC were changed to the values shown in Table 2. Table 2 shows the yields of the resulting PG.

Claims (1)

(57) [Claims] 1. The following formula, (However, R is a hydrogen atom, an alkyl group or a chlorinated alkyl group.) The polychloroalkane represented by the following formula is hydrolyzed in an aqueous solution of an alkali metal or alkaline earth metal hydrogen carbonate or carbonate to give the following formula. (However, R'is a hydrogen atom, an alkyl group, a chlorinated alkyl group or a hydroxyalkyl group.) In the method for producing a polyhydroxyalkane, a hydrogen carbonate or carbonate of an alkali metal or an alkaline earth metal is used. The method for producing a polyhydroxyalkane, which comprises supplying 0.0001 parts by weight to 10 parts by weight of polychloroalkane per minute to 100 parts by weight of water in the aqueous solution and hydrolyzing the solution.