JPH072819A - Purification of glycidol - Google Patents

Abstract

PURPOSE:To provide a method of purification enabling producing high-purity glycidol of high thermal stability with the investment cost limited to a minimum. CONSTITUTION:In conducting a purification of crude glycidol subjected to removing both low-boiling and high-boiling by-products from a glycidol-contg. crude reaction liquor produced by reaction between allyl alcohol and hydrogen peroxide in the presence of a catalyst, a distillation column having a side cut line is used and a side cut column having a theoretical plate number of >=2 is installed on the side cut line.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for purifying glycidyl. Glycidole is a substance useful as a raw material for intermediates of glycidyl ether, glycidyl ester, glycerin ether, glycerin ester, aminopropanediol, etc. for pharmaceuticals, paints, and UV curing agents for semiconductors.

[0002]

2. Description of the Related Art Conventionally, purification of glycidol obtained by reacting allyl alcohol with hydrogen peroxide has been carried out as follows. That is, unreacted allyl alcohol, a part of water and low boiling substances by-produced by the reaction such as acrolein are removed, and further catalysts and high-boiling components such as glycerin and glycerin allyl ether produced as by-products are removed. Then, ordinary distillation is carried out at the top of the column with an appropriate reflux ratio, and the product glycidol is obtained by side-cutting.

[0003]

However, a known manufacturing process (for example, Japanese Patent Publication No. 60-55512).
When glycidol was produced based on, glycidol and glycidaldehyde in the product, and further, the mixing ratio of glycerin and glycidglycerin ether is high, and it can be said that the thermal stability of glycidol is good. There wasn't.

That is, the glycidol obtained in the above experiment had a purity of about 99.3%, and when this glycidol was stored at a temperature near 25 ° C., the decrease in the glycidol content was about 2% per month. .

[0005]

OBJECT OF THE INVENTION It is an object of the present invention to provide a purification method for obtaining glycidol, which is highly pure and has excellent thermal stability, and further, a glycidol derivative having excellent quality. .

[0006]

As a result of intensive studies, the present invention has been made to solve the above-mentioned problems, and it is possible to obtain glycidol having high purity and excellent thermal stability. It is based on the finding of the purification method of.

That is, the present invention is directed to "a crude glycidol which has been subjected to a low boiling point and a high boiling point-treated crude glycidol from a reaction crude liquid containing glycidol obtained by reacting allyl alcohol and hydrogen peroxide in the presence of a catalyst. The method for purifying glycidol is characterized in that a side-cut column having at least two theoretical plates is installed in the side-cut line when purifying in a distillation column having ".

Glycidol is usually produced in the order of reaction step, low boiling point removal step, high boiling point removal step, and commercialization step.
Here, the step before that refers to one or more of a reaction step, a deboiling step and a deboiling step. In this process, when the number of stages of the product column is increased in order to reduce the mixing ratio of acrylic acid and glycidaldehyde in the product, and further, glycerin and glycidglycerin ether, the pressure loss increases.

That is, the temperature at the bottom of the column becomes high and the conversion of glycidol to a high boiling point substance is promoted, which is not preferable.

The object can be achieved by using an ordered packing column capable of satisfying an increase in the number of stages of the product tower and a low pressure loss, but the ordered packing is expensive and economically unfavorable. The point of the present invention is to reduce the mixing ratio of acrylic acid, glycidaldehyde, and further glycerin, glycidglycerin ether, etc. in the product, so that at least theoretical plate 2 is provided in the side cut line of the distillation column having the side cut line. It is the installation of a side-cut tower with steps.

Below 2 theoretical plates, the purity of glycidol is 9
Does not reach 9.7%.

The upper limit of the theoretical plate is not limited, but from the viewpoint of facility economy and pressure loss, about 5 plates is sufficient. It should be noted that the theoretical stage 1 usually corresponds to the actual stage 2 to 3.

The position for feeding the crude glycidol to the productization tower must be above the side cut line withdrawal position and about 45% to 75% from the bottom of the total number of stages of the productization tower.

Further, the liquid extracted from the side cut line is usually 0% to 20% from the bottom of the total number of side cut towers.
Need to be about. If the position is 20% or more from the lower part of the side-cut column, the amount of low-boiling substances will increase, which is not preferable.

An example of a specific process according to the present invention will be described with reference to the attached FIG. 1 which is a block diagram. Here, the commercialization process is shown.

In FIG. 1, 1-1 to 6-6 are conduits connecting the respective devices, and 9/9 is a thin film type evaporator.

7/7 is a distillation column in the production process, 8 /
8 is a side cut tower installed on the side cut line which is the point of the present invention, 10-10 and 11-11 are heat exchangers. The reflux ratio in the distillation column 7/7 in the commercialization process is preferably about 2-3. If the reflux ratio is 3 or more, energy loss increases, which is not preferable.
On the other hand, when it is 2 or less, the amount of low-boiling substances mixed in increases, which is not preferable.

The decatalyzed liquid 1-1 is fed to the productization tower 7-7, the vaporized product containing glycidol and a trace amount of high boiling components passes through 3-3, and the side cut tower 8/8.
Will be fed to. The product glycidol is obtained from 5-5 via a 11-11 heat exchanger. Side cut tower 8 /
The reflux ratio in 8 is preferably about 0.5 to 0.8. If the reflux ratio is 0.8 or more, the energy efficiency is poor, which is not preferable. On the contrary, if it is less than 0.5, the amount of high boiler in the product increases, which is not preferable.

A small amount of low boiling point component is withdrawn from the system from 2-2 through a heat exchanger of 10-10 together with water. The bottoms of the productization tower is discharged from the system through 6-6.

The bottom liquid of the side cut tower 8/8 is returned to the product production tower of 7-7 through 4-4. The composition of the substance flowing through the conduits 1-1 to 6-6 connecting the respective devices is roughly as follows. (Wt%) 1-1: Glycidol 50 to 65% Water 30 to 45% Low boiling point component 0.2 to 0.6% High boiling point component 0.3 to 0.7% 2-2: Glycidyl 1 to 7% Water 92 to 98% Other 0.5 -1.5% 3-3: Glycidole 98.5-99.3% High-boiling point component 95-98% 4-4: Glycidol 95-98% High-boiling point component 2-5% 5-5: Glycidol 99.6-99.8% High boiling point component 0.2 to 0.4% 6-6: Glycidole 50 to 80% High boiling point component 20 to 50% Here, the low boiling point component means allyl alcohol, glycidaldehyde and the like.

Here, the high boiling point component means glycerin, glycerin allyl ether, glycerin multimer and the like.

The effect of the present invention on improving the purity and thermal stability of glycidyl will be described in more detail with reference to the following examples.

[0023]

[Example 1] Liquid 6 that had been subjected to a low boiling point removal process and a high boiling point removal process after the reaction
75.9 kg / hour (glycidyl concentration 59.6% by weight) was used in 1-1 of FIG. 1 to the side cut line 3-3 in the side cut column 8-8 having two theoretical plates (five actual plates). It was fed to the installed commercialization tower 7-7.

As a result, the product glycidin was obtained from 5-5 at 350.2 g / hour (glycidyl concentration 99.7% by weight).
I got Le.

The consistent yield was 75.5%.

When this glycidol was stored at 25 ° C., the reduction in glycidol content was about 1.3% per month.

[0027]

[Comparative Example 1] As Example 1 except that the side cut line 3-3 was fed to a commercialization tower 7-7 in which a side cut tower 8-8 having 1.2 theoretical plates (3 actual plates) was installed. It operated under similar conditions. As a result, the product glycidyl was obtained from 5-5 at a rate of 351.0 g / hour (glycidyl concentration 99.5% by weight).

When this glycidol was stored at 25 ° C., the reduction in glycidol content was about 1.7% per month.

[0029]

[Comparative Example 2] In the commercialization process, an experiment was conducted by an apparatus for removing the sidecut tower from FIG. 1 and obtaining a product by sidecutting from the commercialization tower. The steps before that were performed in the same manner as in Example 1. That is, after the reaction, the solution subjected to the deboiling treatment and the deboiling treatment 675.9 Kg / hour (glycidyl concentration 5
9.6% by weight) was fed to the commercialization tower.

As a result, the product glycidyl was obtained at 353.2 Kg / hour (glycidyl concentration 99.3% by weight).

The consistent yield was 75.8%. When this glycidol was stored at 25 ° C, the reduction in glycidol content was about 2% per month.

[0032]

INDUSTRIAL APPLICABILITY In a distillation column having a side cut line, crude glycidol that has been subjected to a low boiling point and a high boiling point treatment from a reaction crude liquid containing glycidol obtained by reacting a catalyst with allyl alcohol and hydrogen peroxide is used. When purifying
By installing a side-cut column having at least two theoretical plates in the side-cut line, it became possible to produce high-quality glycidol having high purity and excellent thermal stability. (Below margin)

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of a specific process for carrying out the method of the present invention.

[Explanation of symbols]

 1-1 to 6-6: Conduit connecting each equipment 7/7: Distillation tower in commercialization process 8/8: Side cut tower installed on side cut line 9/9: Thin film evaporator 10-10: Heat exchange Vessel 11-11: Heat exchanger

Claims (1)

[Claims] 1. A distillation column having a side cut line, wherein crude glycidol which has been subjected to low boiling point and high boiling point removal from a reaction crude liquid containing glycidol obtained by reacting allyl alcohol and hydrogen peroxide in the presence of a catalyst is used. When purifying
A method for purifying glycidol, characterized in that a side-cut column having at least two theoretical plates is installed in the side-cut line.