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 on three pillars are feeding a mixture of chlorinated propylene in the middle of the first column. Send the distillate of the first column in the middle part of the second column. Serves the distillate of the second column, containing together with "light" fraction of allyl chloride in an amount of 10 to 60 wt.%, on the power of the third column with the selection on it "light" fraction in the distillate and returning its cubic product on one of the plates of the second column. Take the "heavy" fraction in the composition of the cubic product of the first column with the content of allyl chloride in an amount of not more than 10 wt.%. Output VAT product of the second column on one of the plates of the first column in an amount of 0.01 to 0.15 o'clock to 1 o'clock the selected gas in the form of one of the bottom plates of the second column allyl chloride. The technical result - improving the quality of the receiving chlorohydrocarbons by the chlorination of olefins and subsequent separation of the products of chlorination on target and by-products, in particular to 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 two columns included in a method for the 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, in which the separated light fraction output in the form of distillate. The product from the bottom of the first column containing allyl chloride and heavy fraction is sent to the second column. Here allyl chloride is separated from the heavy fraction and displayed 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, 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.

The closest to the technical nature of the claimed invention is a method for the distillation of a mixture of chlorinated propylene in three columns, described in the method of production of allyl chloride, with the supply of chlorinated propylene in the middle of the first column, the direction of the distillate of the first column in the middle part of the second column for separation of allyl chloride in the bottom of the second column, the flow of the distillate of the second column, containing together with "light" fraction of allyl chloride, the power of the third column to separate the light fraction in the distillate to the third pillar, the return of the cubic product of the third column on one of the plates of the second Colo is orprovide propylene come in the middle of the first column, from the lower part of which contains the "heavy" fraction and a 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 method of production is low as allyl chloride. The method does not allow to separate from the end product of 1,5-hexadien and other high-boiling impurities which are present in the original mixture of chlorinated propylene and formed in the rectification system.

The problem to which the invention is directed, is the organization of material flow in the system rectification thus, to reduce the amount of components of the light fraction, in the exercise of the claimed invention lies in the what with the changing organization of material flow in the system rectification improve the quality and 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 in three columns with the filing of a mixture of chlorinated propylene in the middle of the first column, the direction of the distillate of the first column in the middle part of the second column for separation of allyl chloride in the bottom of the second column, the flow of the distillate of the second column, containing together with "light" fraction allyl chloride, in the third column to separate the light fraction in the distillate to the third pillar, the return of the cubic product of the third column on one of the plates of the second column, and the conclusion of "heavy" fraction in the composition of the cubic product of the first column, the process is conducted in such a way that the distillate of the second column with "light" fraction is passed allyl chloride in the amount of 10-60 wt.%, and in CBM product first conducta second column on one of the plates of the first column in the amount of 0.01-0.15 parts per 1 part of the selected gas in the form of one of the bottom plates of the second column allyl chloride.

The process of rectification of a mixture of chlorinated propylene with a pass in the distillate of the second column with "light" fraction of allyl chloride in the amount of 10-60 wt.% provides a more complete separation of the components of the light fraction from commodity allyl chloride.

The separation of the light fraction in the distillate of the third column and return the cubic product of the third column on one of the plates of the second column allows to reduce losses of allyl chloride with "light" fraction, which is typically a waste product of allyl chloride.

The allocation of allyl chloride in gaseous form with one of the bottom plates of the second column with the output part of the cubic product of the second column on one of the plates of the first column in the amount of 0.01-0.15 parts per 1 part taken allyl chloride, and the "heavy" fraction in the composition of the cubic product of the first column with the content of allyl chloride in an amount of not more than 10 wt. % cuts hit 1,5-hexadiene and other high-boiling chlorinated components in the product allyl chloride.

The method is as follows.

The mixture of chlorinated propylene enters the middle part of the first calandruccio, outputted from the rectification system. The distillate of the first column containing the allyl chloride and the "light" fraction with a small number of "heavy" impurities, is displayed on the power of the second column. The distillate of the second column with the content of allyl chloride 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. CBM product of the third column is returned to one of the plates of the second column. In the second column of allyl chloride is released in gaseous form from one of the bottom plates. CBM product of the second column to display on one of the plates of the first column in the amount of 0.01-0.15 parts per 1 part taken allyl chloride.

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

Example 1. Chlorinated propylene containing 4.50 wt.% "light" impurities, 78.70 wt.% chloride and allyl 16.80 wt.% "heavy" impurities in the number 6566.00 kg/hour is served in the middle of the first column. The distillate of the first column containing the allyl chloride and the "light" fraction with a small number of "heavy" impurities, is displayed on the power of the second column in the number 5786.40 kg/hour. The distillate vtoro the th column in the number 487.96 kg/hour. From the top of the third column as distillate output light fraction with a content of chloride allyl 1.10 wt. % number 292.63 kg/hour, and CBM product of the third column in the number 195.33 kg/h is displayed on the feed plate of the second column. The product from the bottom of the first column containing allyl chloride in the amount of 4.50 wt. percent composition and "heavy" fraction, the number 1138.94 kg/h is withdrawn from the rectification system. In the second column of allyl chloride is released in gaseous form from the fourth bottom plates in the number 5134.33 kg/hour. CBM product of the second column to display on the feed plate of the first column in the number 359.34 kg/hour, which amounts to 0.07 parts per 1 part taken allyl chloride.

The content of allyl chloride in the finished product is 99.60% by weight "light" and "heavy" impurities, respectively 0.10 and 0.30 wt.%.

Example 2. Chlorinated propylene containing 3.75 wt.% "light" impurities, 82.17 wt. % allyl chloride and 14.08 wt.% "heavy" impurities in the number 7283.70 kg/hour is served in the middle of the first column. The distillate of the first column containing the allyl chloride and the "light" fraction with a small number of "heavy" impurities, is displayed on the power of the second column in colocasia displayed on the power to the third pillar in the number 520.48 kg/hour. From the top of the third column as distillate output light fraction with a content of chloride allyl 0.37 wt. % number 264.71 kg/hour, and CBM product of the third column in the number 255.77 kg/h is displayed on the feed plate of the second column. The product from the bottom of the first column containing allyl chloride in the amount of 6.30 wt. percent composition and "heavy" fraction, the number 1083.73 kg/h is withdrawn from the rectification system. In the second column of allyl chloride is released in gaseous form from the fourth bottom plates in the number 5935.26 kg/hour. CBM product of the second column to display on the feed plate of the first column in the number 148.38 kg/hour, which is 0.025 parts per 1 part taken allyl chloride.

The content of allyl chloride in the finished product is 99.71% by weight "light" and "heavy" impurities, respectively 0.12 and 0.17 wt.%.

The use of the invention will improve the quality of allyl chloride (reduced content of 1.5-hexadiene, 2-chloropropene and other impurities), 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 way of rectification of the mixture of colony, the direction of the distillate of the first column in the middle part of the second column for separation of allyl chloride in the bottom of the second column, the flow of the distillate of the second column, containing together with "light" fraction allyl chloride, in the third column to separate the light fraction in the distillate to the third pillar, the return of the cubic product of the third column on one of the plates of the second column and the conclusion of "heavy" fraction in the composition of the cubic product of the first column, characterized in that the distillate of the second column with "light" fraction is passed allyl chloride in an amount of 10 to 60 wt. % and VAT product of the first column together with "heavy" fraction is passed allyl chloride in an amount of not more than 10 wt. %, and allyl chloride selected gas in the form of one of the bottom plates of the second column with the conclusion of the cubic product of the second column on one of the plates of the first column in an amount of 0.01 to 0.15 o'clock to 1 o'clock selected allyl chloride.

 

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