Patent ID: 6900363

Claim:
A process for preparing 1,2-dichloroethane, which comprises (A) feeding an ethane-containing feed gas stream into a dehydrogenation zone and dehydrogenating ethane to ethene to give a product gas stream comprising ethane, ethene and secondary constituents, (B1) feeding a first substream of the ethane- and ethene-containing dehydrogenation product gas stream, optionally after having separated off secondary constituents, into an oxychlorination zone, oxychlorinating ethene to 1,2-dichloroethane to give a product gas stream comprising 1,2-dichloroethane, ethane and possibly further secondary constituents, isolating 1,2-dichloroethane and an ethane-containing circulating gas stream and recirculating the ethane-containing circulating gas stream to the ethane dehydrogenation, (B2) feeding a second substream of the ethane- and ethene-containing dehydrogenation product gas stream, optionally after having separated off secondary constituents, into a direct chlorination zone, directly chlorinating ethene to 1,2-dichloroethane to give a product gas stream comprising 1,2-dichloroethane, ethane and possibly further secondary constituents, isolating 1,2-dichloroethane and an ethane-containing circulating gas stream and recirculating the ethane-containing circulating gas stream to the ethane dehydrogenation, (C) feeding 1,2-dichloroethane from the oxychlorination and from the direct chlorination into a pyrolysis zone, pyrolyzing 1,2-dichloroethane to vinyl chloride to give a product gas stream comprising vinyl chloride, hydrogen chloride, 1,2-dichloroethane and possibly secondary constituents, isolating vinyl chloride and recirculating hydrogen chloride to the oxychlorination.