The method of distillation of a mixture of chlorinated propylene

 

(57) Abstract:

The invention relates to a technology for chlorohydrocarbons by the chlorination of olefins and subsequent separation of the products of chlorination on target and by-products, in particular to a method of rectification of a mixture of chlorinated propylene with obtaining allyl chloride of high purity. The process of rectification of a mixture of chlorinated propylene with selection of the "heavy" and "light" fractions and allyl chloride are three columns with the supply of chlorinated propylene in the middle of the first column. Send CBM product of the first column in the middle part of the second column for separating a heavy fraction from allyl chloride in the form of the cubic product of the second column. In the distillate of the first column together with the "light" fraction is passed allyl chloride in the amount of 10-60 wt.% the composition of the distillate feed part of it on the third column to separate the light fraction in the distillate third columns with content in it allyl chloride not more than 4 wt.%. Output VAT product of the third column on one of the plates, located between the upper part and a plate of food the first column. Produce allyl chloride in the form of a distillate of the second column or in the bottom of the plates, located between the lower part and a plate of food the first column in an amount of 0.01 to 0.15 parts per 1 part taken allyl chloride. Effect: increase the quality of allyl chloride, reduction of by-products and energy costs.

The invention relates to a technology for chlorohydrocarbons by the chlorination of olefins and subsequent separation of the products of chlorination on target and by-products, in particular to a method of rectification of a mixture of chlorinated propylene with obtaining allyl chloride of high purity.

To obtain the allyl chloride used in industry method of high-temperature chlorination of propylene, followed by separation of the reaction products of a mixture of chlorinated propylene and their rectification in two or three columns.

The known method of rectification of a mixture of chlorinated propylene in three columns with selection of the "heavy" and "light" fractions and allyl chloride, described in the method of production of allyl chloride, with the supply of chlorinated propylene in the middle of the first column, the separation of the heavy fraction in the form of the cubic product of the first column, the direction of the first distillate CCW allyl, taken in the form of the cubic product of the second column. The distillate of the second column with "light" fraction skip a bit allyl chloride. The distillate of the second column serves to supply a third column for a more complete separation of allyl chloride from "easy" fractions taken in the form of distillate third column, CBM product of the third column return to power of the second column.

Chlorinated propylene come in the middle of the first column, from the lower part of which contains the "heavy" fraction; distillate containing allyl chloride and "light" fraction from the top of the column is sent to the second column. Here allyl chloride is separated from the light fraction and at a concentration of 97-98 wt.% is withdrawn from the bottom of the column as a finished product. The distillate of the second column containing light fraction and a bit of allyl chloride, is fed to a third column, where the top displays only the "light" fraction, and the product from the bottom of the column containing mainly allyl chloride and a small amount of "light" fraction is returned to the power of the second column /Industrial organochlorine products. The Handbook. Ed. by L. A. Osina. - M.: Chemistry, 1978. - 656 pages/.

The disadvantage of this product 1,5-hexadien, present in the original mixture of chlorinated propylene and formed in the second column as a result of thermal decomposition reactions and the dimerization of 2-chloropropene and allyl chloride. In addition, the same reactions thermal decomposition of 2-chloropropene and allyl chloride is secreted hydrogen chloride and by associating it with unsaturated chlorinated propylene formed high-boiling impurities. Separating them from the cubic product of the second column is not possible.

The closest to the technical nature of the claimed invention is a method for the distillation of a mixture of chlorinated propylene in two columns with selection of the "heavy" and "light" fractions and allyl chloride, which is a method of production of allyl chloride, with the supply of chlorinated propylene in the middle of the first column, the separation of the light fraction in the distillate from this column, the direction of the cubic product of the first column in the middle part of the second column to separate the heavy fraction in the form of the cubic product of allyl chloride taken in the form of a distillate of the second column, as the finished product.

Chlorinated propylene come in the middle of the first column, W is th allyl and "heavy" fraction, is sent to the second column. Here allyl chloride is separated from the heavy fraction and appears in the form of distillate as a finished product with a concentration of about 98.5 wt. %. Heavy fraction is withdrawn from the second column in the form of the cubic product /Patent Poland 139088, MKI407 With 21/067, publ. 16.01.85/.

The disadvantage of this method of production is the difficulty in achieving high quality allyl chloride. Want to maintain a high reflux numbers on the first column, which leads to greater consumption of energy costs. This decrease allyl chloride with output as a waste product of a light fraction and a reduced content of components of the light fraction in bottom product of this column and, as a consequence, in the distillate of the second column.

If rectification of the mixture of chlorinated propylene with obtaining allyl chloride of high purity it is important to observe a number of conditions, namely:

- to ensure the organization of material flow in the system rectification thus, in order to prevent the leakage components of the light fraction in the final product;

- do not allow selection of allyl chloride in the form of the cubic product, because Rea is locaiton and 1.5-hexadiene, the Department from which the cubic product represents a significant additional cost.

The challenge which seeks the invention is to improve the quality of allyl chloride and reduction of the energy consumption in the distillation of a mixture of chlorinated propylene.

The technical result in the implementation of the claimed invention is that by improving the quality of allyl chloride and reduction of the energy consumption in the distillation of a mixture of chlorinated propylene improve consumer properties of allyl chloride, reduces the amount of by-products and improving the quality of products when using allyl chloride as an intermediate product in various industries.

This technical result in the implementation of the invention is achieved in that in the known method of rectification of a mixture of chlorinated propylene with selection of the "heavy" and "light" fractions and allyl chloride feed chlorinated propylene in the middle of the first column, the direction of the cubic product of the first column in the middle part of the second column to separate the heavy impurities from allyl chloride in the form of kubovo the "light" fraction is passed allyl chloride in the amount of 10-60 wt.% the composition of the distillate, with the supply of part of it on the third column to separate the light fraction in the distillate of the column with the content of allyl chloride not more than 4 wt.%, the output of the cubic product of the third column on one of the plates, located between the upper part and a plate of food the first column, and the allocation of allyl chloride in the form of a distillate of the second column or in a liquid form with one of the top plates of the second column, feeding a part of the distillate with one of the plates, located between the lower part and a plate of food the first column in an amount of 0.01 to 0.15 parts per 1 part taken allyl chloride.

The process of rectification of a mixture of chlorinated propylene with a pass in the distillate of the first column together with the "light" fraction of allyl chloride in the amount of 10-60 wt.% the composition of the distillate provides a more complete separation of the components of the light fraction from the cubic product, from getting into the commodity allyl chloride and reduces energy costs in the second column.

The separation of the light fraction in the distillate of the third column with the content of allyl chloride not more than 4 wt.% and the conclusion of the cubic product of the third column on one of the plates, are placed the coy" faction, which, as a rule, the waste product of allyl chloride.

The allocation of allyl chloride in the form of a distillate of the second column or in a liquid form with one of the top plates of the second column with the feed portion of the distillate with one of the plates, located between the lower part and a plate of food the first column, in an amount of 0.01 to 0.15 parts per 1 part taken allyl chloride, and the "heavy" impurities in the form of the cubic product of the second column, allows you to prevent entering the commodity allyl chloride 1,5-hexadiene and other components of the heavy fraction, which are products of the reactions of thermal decomposition and the dimerization of 2-chloropropene and allyl chloride.

Chlorinated propylene come in the middle of the first column. The distillate of the first column with the content of allyl chloride in it 10-60 wt.% together with "light" fraction is displayed on the power to the third pillar. From the top of the third column as distillate output light fraction with a concentration of allyl chloride not more than 4 wt.%. CBM product of the third column is displayed on one of the plates, located between the upper part and a plate of food the first column. The product from the bottom of the first column containing allyl chloride and heavy and and appears in the form of distillate or in liquid form with one of the top plates with the supply portion of the distillate with one of the plates, located between the lower part and a plate of food the first column, in an amount of 0.01 to 0.15 parts per 1 part taken allyl chloride. "Heavy" fraction in the form of the cubic product of the second column is displayed for recycling.

The content of allyl chloride in the finished product is not less than 99.50 wt.%.

Example 1. Chlorinated propylene containing 3.53 wt.% "light" impurities, 67.00 wt. % allyl chloride and 29.47 wt.% "heavy" impurities in the number 6300.00 kg/h served in the middle of the first column. The distillate of the first column with the content of allyl chloride in him 35.0 wt.% together with "light" fraction is displayed on the power to the third pillar in the number 420,07 kg/h From the top of the third column as distillate output light fraction with a content of chloride allyl 0.22 wt.% the number 216.53 kg/h, and CBM product of the third column in the number 203.54 kg/h is displayed on one of the plates, located between the upper part and a plate of food the first column. The product from the bottom of the first column containing allyl chloride and heavy fraction, the number 6083.47 kg/h is sent to the second column. In the second column of allyl chloride is separated from the heavy fraction and appears in the form of distillate in Cricetidae.

The content of allyl chloride in the finished product is 99.75 wt.%, "light" and "heavy" impurities respectively 0.15 and 0.10 wt.%.

Example 2. Chlorinated propylene containing 4.68 wt.% "light" impurities, 76.62 wt.% chloride and allyl 18.70 wt.% "heavy" impurities in the number 8360.00 kg/h served in the middle of the first column. The distillate of the first column with the content of allyl chloride in it 28.0 wt.% together with "light" fraction is displayed on the power to the third pillar in the number 639.74 kg/h From the top of the third column as distillate output light fraction with a content of chloride allyl 0.38 wt.% the number 389.53 kg/h, and CBM product of the third column in the number 250.21 kg/h is displayed on one of the plates, located between the upper part and a plate of food the first column. The product from the bottom of the first column containing allyl chloride and heavy fraction, the number 8098.52 kg/h is sent to the second column. In the second column of allyl chloride is separated from the heavy fraction and displayed in a liquid form with one of the upper plates in the number 6402.39 kg/h, and the part of the distillate in the amount of 128.05 kg/h, which is 0.02 parts per 1 part taken allyl chloride, served on a plate of food first number is

The content of allyl chloride in the finished product is 99.87% by weight, "light" and "heavy" impurities respectively 0.05 and 0.08 wt.%.

The use of the invention will improve the quality of allyl chloride (reduced content of 1.5-hexadiene, 2-chloropropene and other impurities), to reduce the energy costs of rectification chlorinated propylene, and reduce the amount of by-products and improve the quality of products when using allyl chloride as an intermediate product in various industries.

The method of distillation of a mixture of chlorinated propylene with selection of the "heavy" and "light" fractions and allyl chloride feed chlorinated propylene in the middle of the first column, the direction of the cubic product of the first column in the middle part of the second column to separate the heavy fraction in the form of the cubic product of the second column from allyl chloride, wherein the process is conducted in three columns so that the distillate of the first column together with the "light" fraction is passed allyl chloride in the amount of 10-60 wt. % composition of the distillate, with the supply of part of it on the third column to separate the light fraction in the distillate of the third column from the trees, located between the upper part and a plate of food the first column, and the allocation of allyl chloride in the form of a distillate of the second column or in a liquid form with one of the top plates of the second column with the feed portion of the distillate of the second column on one of the plates, located between the lower part and a plate of food the first column in an amount of 0.01 to 0.15 parts per 1 part taken allyl chloride.

 

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