SU535269A1 - The method of separation of chlorine paraffin - Google Patents

Description

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This invention relates to a process for the preparation of highly chlorinated paraffins used as flame retardants to reduce the flammability of polymeric materials.

Chlorine paraffins are usually obtained by chlorinating paraffin (from a chain of € 20 - Cs2) in a solvent inert to chlorine in the presence of an initiator. Isolation of chloroparaffin is carried out by distilling off the solvent with steam and then following. The product is not of high quality, and the method is difficult to process 1.

There is also known a method for the separation of chloroparaffin from the reaction mass obtained by chlorinating paraffin (with a C20-SZB chain length) in carbon tetrachloride and removing the solvent in a film evaporator at 100-140 ° C.

The residence time of the reaction mass in the release zone, the feed rate of the solution, the concentration and film thickness are not indicated 2.

The disadvantage of this method is the low quality of chloroparaffin. The deterioration of the quality of the product occurs due to the ability of chloroparaffin to adsorb and retain residual solvent, in particular carbon tetrachloride. The use of the elevated temperatures necessary for the complete extraction of the solvent from a film of a viscous solution having a thickness of more than a few millimeters leads to the decomposition of chlorine paraffin with the elimination of hydrogen chloride, darkening and pitch.

The film thickness is provided by the temperature in the release zone, the feed rate of the solution and its concentration.

In order to eliminate the above disadvantages, namely, to improve the quality of chlorine paraffin, it is proposed to release chlorine paraffin from the reaction mass obtained by chlorinating paraffin in the medium of an organochlorine solvent from a free flowing solution film at 140–200 ° C, the residence time of the reaction mass in the zone of separation 3-10 min and film thickness of 0.5-2 mm under pressure of 0.1-0.75 at, in the presence of a stabilizer, taken in an amount of 1.0-1.6% by weight of chlorine paraffin, and a compound forming complexes with iron, addition in quantity 0.01-0.1% by weight of chloroparaffin.

It is preferable to conduct the process at 150-170 ° C.

It is desirable to use epoxy, magic compounds or glycols as a stabilizer.

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It is also preferable to use amines or phosphates as compounds forming complexes with iron.

Example. A solution of chloroparaffin with a chlorine content of 68-73.5% and a concentration of 50-55% in an organochlorine solvent, in particular in CC14, after stripping off unreacted chlorine and adsorbed hydrogen chloride, introduces a stabilizer, taken in an amount of 1.0-1.6 % by weight of chloroparaffin, and a compound forming complexes with iron, taken in an amount of 0.01-0.3% by weight of chloroparaffin.

A solution with a speed of 1.0-1.25 l / h through a heat exchanger with a temperature of 60 ° C is fed to a film evaporator, which is heated by a heat transfer agent having a temperature of 140- 200 ° C.

The solution flows evenly through the tubes in the form of a film. In the release zone, the solvent is evaporated from the reaction mass under a pressure of 0.1-0.7 at. Vapor is withdrawn from the top of the apparatus and sent to condensation for return to recycling.

The data and results for the method of separation of chlorine paraffin are shown in the table.

Creating a film mode at 140-200 ° C, the residence time of the reaction mass in the release zone 3-10 minutes and a film thickness of 0.5-2 mm allows the solvent to be completely removed, a good quality product is obtained, i.e. the solvent release becomes easily controlled and ensures effective process performance.

Claims (4)

1. A method of separating chloroparaffin from the reaction mass obtained by chlorinating paraffin in an environment of an organochlorine solvent from a film of a free-flowing solution at an elevated temperature, characterized in that, in order to improve the quality of chloroparaffin, the process is carried out at 140-200 ° C, the residence time of the reaction mass in a release zone of 3–10 min and a film thickness of 0.5–2 mm under a pressure of 0.1–0.7 at, in the presence of a stabilizer, taken in an amount of 1.0–1.6% by weight of chloroparaffin, and a compound forming iron complexes, taken in an amount of 0.01 -0.1% by weight of chloroparaffin. 2. A method according to claim 1, wherein the process is carried out at 150-170 ° C. 3. A method according to claim 1, characterized in that epoxy resin, magnesium compounds or glycols are used as a stabilizer. 4. A method according to claim 1, characterized in that amines or phosphates are used as compounds forming complexes with iron. Sources of information taken into account in the examination: 1. Vorobieva N. G., Zaidman O. A. “Production and properties of chlorine paraffin. Chem. industry, NIITEKHIM, Vol. 547, p. 138, 1970. 2.Patent of Poland No. 57653, Cl. 12 O 2/01, 1966 (prototype).