Chlorination of acetylenes

Chlorinated Solvents. Originally, successive chlorination and dehydro-chlorination of acetylene was the route to trichloroethylene [79-01-6], C2HCI3, and perchloroethylene [127-18-4], C2C1. ... 

Other routes to 1,1,2-trichloroethane are chlorination of acetylene in the presence of HCl (101) and chlorination of vinyl chloride at room temperatures with FeCl (102—104), hydrochlorination of cis- and /n j -l,2-dichloroethylene with FeCl catalyst (105), vapor-phase oxychlorination of... 

Dichloroethylene can be produced by direct chlorination of acetylene at 40°C. It is often produced as a by-product ia the chlorination of chloriaated compounds (2) and recycled as an iatermediate for the synthesis of more useful chloriaated ethylenes (3). 1,2-Dichloroethylene can be formed by contiauous oxychloriaation of ethylene by use of a cupric chloride—potassium chloride catalyst, as the first step ia the manufacture of vinyl chloride [75-01-4] (4). 

Many processes have been used to produce tetrachloroethylene. One of the first was chlorination of acetylene (C2H2) to form tetrachloroethane, followed by dehydrochlorination to trichloroethylene. If tetrachloroethylene was desired, the trichloroethylene was further chlorinated to pentachloroethane and dehydrochlorinated. This process is no longer used in the United States Hooker Chemical closed down the last plant in 1978. 

Uses. 1,2-Dichloroethylene is used as a solvent for organic materials and as an intermediate in the synthesis of other chlorinated compounds it may be produced by the chlorination of acetylene but is often produced as a by-product in the manufacture of other chlorinated compounds. 

ELECTROPHILIC ADDITIONS TO CARBON-CARBON MULTIPLE BONDS A. Chlorinating agents Sodium hypochlorite solution 7V-Chloro succi n i m i de Antimony pentachloride Formation of chlorohydrins from alkenes Chlorination with solvent participation and cyclization Controlled chlorination of acetylenes... 

The tech product contains varying proportions of trans cis isomers depending upon the conditions of manuf. A typical tech product boils in the range 45-60°, has a flash, p of 6°, and expin limits in air 9-7-12.8% by vol. This compd burns with diffic but it forms expl mixts with air. It is produced by reduction of 1,1,2,2-tetrachloroethane or by direct chlorination of acetylene... 

Brailovskii, S. M., Man Khoan, K., Temkin, O. N. Kinetics and mechanism of additive oxidative chlorination of acetylene in solutions of Cu(l)... 

Manufactured by chlorination of acetylene or other two carbon hydrocarbons or by dehydrohalogenation... 

Derivation Two stereoisomeric compounds made by the partial chlorination of acetylene. 

Derivation By chlorination of trichloroethylene, obtained by a two-step process involving chlorination of acetylene to obtain tetrachloroethane, and removal of hydrogen chloride by action of alkali. 

Chlorination of Acetylene. Tetrachloroethane. The production of tetra-chloroethane by the addition chlorination of acetylene is probably best carried out by the Wacker process. Here a large body of the final product, tetrachloroethane, is used as a diluent for the reacting gases anhydrous ferric chloride is the catalyst, and the reaction is carried out under reduced pressures. The principal facilities (Fig. 6-13) are a tetrachloroethane generator which comprises a dephlegmator superimposed on the reactor (chlorinator) and a chlorine absorption tower that is integrated with a cooling system. 

The use of high-purity chlorine containing only small amounts of dissolved imf)urities has been shown to be advantageous in preventing formation of undesirable by-products in this chlorination of acetylene. It is believed, however, that this absorption procedure is no longer used because the yield of C2H2CU is relatively low. 

There are various methods by which the unsymmetrical dichloroethylene, vinylidene chloride, can be produced commercially. The first process is based on the chlorination of acetylene carried out in acetylene tetrachloride (tetrachloroethane). In the presence of ferric chloride, which acts as a catalyst, acetylene and chlorine combine at 135°C and yield vii lidene chloride. Another method of vinylidene chloride production starts from ethylene, which is chlorinated under controlled conditions to yield, 1,1,2-tri-chloroethane. On heating the latter substance in the presence of an alkali, hydrochloric acid is split off and a mixture of isomeric dichloroethylenes is obtiuned. They can be separated by fractional distillation. 

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