Process for preparing trichloroethylene

In a process for making trichloroethylene by chlorinating 1,2-dichloroethane in the liquid phase in the presence of ethylene followed by simultaneous chlorination and dehydrochlorination of the liquid phase reaction product, the improvement comprising:

• a. chlorinating 1,2-dichloroethane in the liquid phase in the presence of about 1 to 10 moles percent of ethylene relative to chlorine employed with a chlorine feed molar consumption ratio of chlorine to 1,2-dichloroethane of about 0.7 to 1.4 to 1 at temperatures ranging from about 40.degree. to 150.degree. C, a superficial gas velocity in excess of 8 cm/second and gas dwell times of about 0.3 to 10 seconds producing a liquid phase chlorinated product;
• b. reacting said liquid phase chlorinated product in the gas phase with recycled tetrachloroethanes and chlorine wherein about 20 - 70 moles of chlorine are reacted with 100 moles of chlorinated hydrocarbons at temperatures of from about 380.degree. to 500.degree. C and the dwell times are about 20 to 30 seconds producing a gas phase chlorinated product;
• c. said gas phase chlorinated product is quenched to separate hydrogen chloride and producing a quenched gas phase chlorinated product, said quenched gas phase chlorinated product is separated by distillation into a low boiling point dichloroethylene fraction and a high boiling point trichloroethylene fraction;
• d. reacting said dichloroethylene fraction in the liquid phase with equimolar amounts of chlorine at temperatures of from about 60.degree. to 150.degree. C to produce said recycled tetrachloroethanes comprising symmetrical and asymmetrical tetrachloroethanes and recycling said tetrachloroethanes to step (b);
• and
• e. separating by distillation said high boiling point trichloroethylene fraction to produce trichloroethylene product.