JPS6137747A - Production of glycerol dichlorohydrin - Google Patents

Abstract

PURPOSE:To suppress the formation of by-products, and to improve the purity of the titled compound useful as a synthetic intermediate of glycerol, etc., easily, by reacting allyl chloride with chlorine in the presence of water and more than a specific amount of a radical scavenger. CONSTITUTION:The objective compound can be produced by reacting allyl chloride with chlorine in the presence of water. The above reaction is carried out in the presence of >=10ppm, preferably 50-1,000ppm of a radical scavenger based on allyl chloride, at 0-60 deg.C under atmospheric or positive pressure. The radical scavenger is e.g. hydroquinone, p-tert-butylcathechol, p-benzoquinone, etc. The amount of chlorine is 0.9-1.1mol per 1mol of the allyl chloride used as a raw material, and that of water is 100-350mol per 1mol of allyl chloride. The allyl chloride used as the raw material is synthesized by the thermal chlorination of propylene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing glycerol dichlorohydrin.

More specifically, the present invention relates to a method for producing glycerin dichlorohydrin having an extremely low content of dichloropropanes.

Glycerin dichlorohydrin is useful as an intermediate for making epichlorohydrin or glycerin.

The method for industrially producing glycerin dichlorohydrin is generally to chlorinate propylene to produce allyl chloride, and then to react the allyl chloride with chlorine in the presence of water (chlorohydrination) to produce glycerin dichlorohydrin. Depends on the method.

However, the glycerin dichlorohydrin obtained by this method contains several hundred ppm each of 1,2-dichloropropane and 1,8-dichloropropane, and glycerin dichlorohydrin containing these dichloropropanes is These dichloropropanes, which are also converted into epichlorohydrin by dehydrochlorination, are difficult to separate from epichlorohydrin because their boiling points are close to that of epichlorohydrin, posing a problem in terms of the quality of epichlorohydrin.

Therefore, the development of a method for producing glycerin dichlorohydrin with a low content of dichloropropanes is expected.

In order to overcome such disadvantages, the present inventors investigated the production of dichloropropanes, and found that the dichloropropanes are 1-chloropropane and 2-chloropropane, which are produced as by-products together with allyl chloride in the process of chlorinating propylene. Propane is produced by reacting with chlorine in the chlorohydrination process, and by coexisting a radical scavenger in the reaction solution, the content of dichloropropanes in glycerin dichlorohydrin can be significantly reduced. They discovered this and completed the present invention.

That is, in producing glycerin dichlorohydrin by reacting allyl chloride with chlorine in the presence of water, the present invention provides dichlorohydrin by reacting in the presence of a radical scavenger of 10 ppm or more with respect to allyl chloride. An object of the present invention is to provide a method for producing glycerin dichlorohydrin with a low content of chloropropanes. The method of the present invention will be explained in detail below.

In carrying out the method of the present invention, the raw material allyl chloride is as follows:
Allyl chloride obtained by thermal chlorination of propylene is used, typically 1-chloropropane 2 after quenching the reaction product from the thermal chlorination step and then distilling the crude reaction product. Allyl chloride containing up to 1% by weight of 2-chloropropane is used.

In carrying out the method of the present invention, the above-mentioned allyl chloride is reacted with chlorine in the presence of water to form glycerin dichlorohydrin. The purpose is to allow the reaction to occur in the presence of dichloropropanes, thereby producing glycerine dichlorohydrin with a low content of dichloropropanes. If the amount of the radical scavenger present in the chlorohydrination reaction system is less than 10 ppm based on allyl chloride, the effect of inhibiting the production of dichloropropanes will be insufficient, which is not preferable.

On the other hand, even if the amount of radical scavenger present is large, an effect proportional to the amount added cannot be obtained, so it is generally added in an amount of 1Qpprn to 10.000ppm, preferably 50 pI)m to tooppm, relative to allyl chloride. .

This method achieves the effect that the production of dichloropropanes in 1glycerol dichlorohydrin can be reduced to 1/1 degree or less. The radical scavenger can be added to the chlorohydrination reaction system by dissolving the radical scavenger in allyl chloride and supplying it, dissolving the radical scavenger in water and supplying it, or adding the radical scavenger directly to the reaction solution. The supply method etc. is adopted Ji-7S
The scrohydrination reaction is carried out by reacting chlorine at a ratio of 0.9 to 1.1 moles with respect to 1 mole of raw material allyl chloride. Although the amount of water supplied varies depending on the aqueous glycerin dichlorohydrin solution extracted from the system, it is generally supplied to the reaction system at a ratio of 100 to 850 moles of water per 1 mole of raw material allyl chloride. The chlorohydrination step is generally carried out under temperature conditions of 0 to 60°C. Further, the chlorohydrination reaction can be carried out under either normal pressure or pressurized conditions.

The implementation format of the chlorohydrination reaction is not particularly limited, and any known method can be adopted, but this method is proposed as a method for reducing the by-product of 1゜2.8-trichloropropane, which is a chlorination reaction product of allyl chloride. For example, a method in which allyl chloride, chlorine, and water are introduced from the lower part of the reaction tower and reacted in the tower, and the resulting glycerin dichlorohydrin aqueous solution is continuously discharged from the upper part of the reaction tower.
11 VIJIlf-1-su 11? ” A'A II +IJta Tar YuL
A method of supplying 11% t- in the form of an aqueous solution and reacting,
Generally, a method is adopted in which chlorine is absorbed into the circulating reaction liquid in a packed column, and the resulting chlorine-containing liquid and allyl chloride emulsion are fed to a reactor and reacted.

Of course, in any reaction type, it is still necessary to have a radical scavenger present in the reaction system.

In carrying out the method of the present invention, compounds known as so-called polymerization inhibitors can be used as radical scavengers. Specifically, hydroxy compounds such as hydroquinone, hydroquinone monomethyl ether, p-tert-butyl-catechol, and catechol, quinone compounds such as p-benzoquinone and anthraquinone, and amino compounds such as phenothiazine and p-phenylenediamine are used. .

The fact that the production of dichloropropanes can be significantly suppressed by the method of the present invention suggests that dichloropropanes are produced by the following radical chain reaction, and that oxygen is efficiently It is thought that the formation of dichloropropanes can be suppressed by stopping the radical chain reaction.

Chain reaction CHs CHg01s Ct + Ct--+ CHa
Q(Q(2Ct + HCtCHaCHCHgCt +
Cts → CHscHQhCt + Ct, ・Ct Chain termination CH3CHO (2CA + radical scavenger → inactivation Glycerin dichlorohydrin with a low content of dichloropropanes obtained as above is a raw material for manufacturing epichlorohydrin, glycerin, etc.) It is effectively used as

According to the method of the present invention as described above, a remarkable industrial advantage is exhibited in that glycerine dichlorohydrin with a low content of impurities such as dichloropropanes can be economically produced by an extremely simple method.

The method of the present invention will be explained in more detail with reference to Examples below, but the method of the present invention is not limited thereto.

Example 1 An apparatus consisting of chlorine supply pipes 4, 10, allyl chloride supply pipe 2.8, circulation pump 8.9, and reactor as shown in FIG.
Glycerin dichlorohydrin was synthesized using a reaction temperature of 80°C.

1.24 L of water is supplied from line 1 to the reaction liquid which is being circulated through line 6 at 2700 t/hr by circulation pump 8.
/Hr, allyl chloride (containing 0.41% by weight of 1-chloropropane and 0.08% by weight of 2-chloropropane) was supplied from line 2 at 20.8 f/Hr, while allyl chloride was 100 ppm of hydroquinone monomethyl ether, oxygen 0.0 from line 4
6. Chlorine containing 0.14% by weight. INt/Hr was blown into the reactor 5 having a capacity of 4 t to carry out the reaction with stirring. Most of the reaction liquid is circulated through line 6, with 1.24
L/Hr of the reaction solution was introduced from line 7 into the next circulation system.

In the second circulation system, the circulation pump 9 generates 270 OA/
1.24 A/Hrf /Hr of the reaction liquid from the previous circulation system was supplied through line 8 to the reaction liquid circulating in line 12 at a rate of 1.24 A/Hrf /Hr. Furthermore, from line 15 to allyl chloride supplied from line 8, 0.00 ppm of hydroquinone was added from the methyl ether line 10.
Chlorine containing 14% oxygen by weight6. I Nt/Hr was blown into the reactor, and the reaction was carried out with stirring in a reactor 11 having a volume of 4 tons. Most of the reaction liquid is circulated through line 12 and line 18
Then, a reaction solution containing 5% by weight of glycerin dichlorohydrin was extracted at 1.8 tAlr.

The yield of glycerin dichlorohydrin was 92.9 mol% based on the supplied allyl chloride, and the content of 1,2-dichloropropane and 1,8-dichloropropane in glycerin dichlorohydrin was 20 I)I, respectively. ) m, gppm
Met.

Comparative Example A glycerin dichlorohydrin aqueous solution was produced in exactly the same manner as in Example 1 except that hydroquinone monomethyl ether was not supplied from line 16. The yield of glycerin dichlorohydrin was 92.6 mol% based on the supplied furyl chloride, but the contents of 1,2-dichloropropane and 1,8-dichloropropane in glycerin dichlorohydrin were respectively 2iyppm, 78 ppm
It was m.

From the above, it is clear that the presence of a radical scavenger in the chlorohydrination step is effective in suppressing by-products.

Example 2 Using an apparatus consisting of a chlorine absorption tower 28, an allyl chloride mixer 26, and a reactor 25 as shown in Fig. 2, the reaction temperature was 80°C.
Glycerin dichlorohydrin was synthesized.

Water supplied from line 204. a t/Hr, line 80
Circulating liquid a OL/Hr is supplied from the top of the 10 cmφ x 1 fn packed chlorine absorption tower 28, while 80 tons/Hr of chlorine containing 0.0014% by weight of oxygen is supplied to the bottom of the tower from the line 21. Then, from line 22, iooppm of phenothiazine was blown into the allyl chloride. Chlorine water was taken out from line 24 and supplied to a stirred tank reactor 25 with a capacity of 4 tons. On the other hand, in line 27, allyl chloride (containing 0.41% by weight of 1-chloropropane and 0,000% by weight of 2-chloropropane) was mixed at a rate of 0.1 h/Hr in an allyl chloride mixer with a volume of 0.5 t. 26, the circulating liquid was supplied from the other line 81 to the mixer 26 at 2 Q L/Hr and mixed, and then supplied to the reactor 25 via the line 28. The glycerine dichlorohydrin aqueous solution produced in the reactor 25 It was extracted through line 29 at a rate of 4.45-old r.

The concentration of glycerin dichlorohydrin in the extracted liquid is 8.
It was 6% by weight.

The yield of glycerin dichlorohydrin was 94.0 mol% based on the supplied allyl chloride, and the content of 1,2-dichloropropane and 1,8-dichloropropane in glycerin dichlorohydrin was 19I). pm, iopp
It was m.

Example 8 A glycerin dichlorohydrin aqueous solution was produced in exactly the same manner as in Example 1 except that p-benzoquinone 1100p1) was used instead of phenothiazine.

The yield of glycerin dichlorohydrin was 92.4 mol% based on the supplied allyl chloride, and the contents of 1,2-dichloropropane and 1,8-dichloropropane in glycerin dichlorohydrin were each 251) 1) m, itp
It was pm.

[Brief explanation of the drawing]

1-2 are flow sheets showing embodiments of the method of the present invention. 1.6.7.12.1B, 14. ,,,,line 2,
8, Allyl chloride supply pipe 8, 9, Pump 4.1G, Chlorine supply pipe 5, 11, Reactor 15, Radical scavenger supply pipe 2G,
24,,! 8.29.80.81 ,,, line 2
1... Chlorine supply pipe 22 , Radical scavenger supply pipe 28...
...Chlorine/absorption tower 25...Reactor

Claims (1)

[Claims] 1) In producing glycerin dichlorohydrin by reacting allyl chloride with chlorine in the presence of water, the reaction is carried out in the presence of a radical scavenger of 10 ppm or more with respect to allyl chloride. 2) A method for producing glycerin dichlorohydrin according to claim 1, characterized in that a hydroxy compound is used as a radical scavenger. 3) A quinone as a radical scavenger. 4) A method for producing glycerin dichlorohydrin according to claim 1, characterized in that a compound is used. 4) A method for producing glycerin dichlorohydrin according to claim 1, characterized in that an amino compound is used as a radical scavenger. Production method of hydrin