Ethylene Bichloride EDC

In contrast to this direct chlorination there is the oxychlorination of ethylene using hydrogen chloride and oxygen, the other major method now used. Since the chlorine supply is sometimes short and it is difficult to balance the caustic soda and chlorine demand (both are made by the electrolysis of brine), hydrogen chloride provides a cheap alternate source for the chlorine atom. Most of the ethylene dichloride manufactured is converted into vinyl chloride by eliminating a mole of HCl, which can then be recycled and used to make more EDC by oxychlorination. EDC and vinyl chloride plants usually are physically linked. Most plants are 50 50 direct chlorinationroxychlorination to balance the output of HCl. 

What probably happens in the oxychlorination process is that chlorine is formed in situ. The reaction of hydrogen chloride and oxygen to give chlorine and water was discovered by Deacon in 1858. Once the chlorine is formed, it then adds to ethylene as in the direct chlorination mechanism. Cu  

Ethylene dichloride is a colorless liquid with a bp of 84°C. As with many chlorinated hydrocarbons, it is quite toxic and has a TLV value of 10 ppm (TWA). It is on the list of Reasonably Anticipated to Be Human Carcinogens.  

Despite these minor uses, the economics of EDC is linked to the demand for PVC plastic. 

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