TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The effluent stream comprises dimethyl ether (at least 500 ppm, preferably not more than 50 wt.%), ethylene (25-75 wt.%), and propylene (25-75 wt.%). It comprises 50-95 wt.% combined ethylene and propylene. It may contain water (not more than 15000, preferably 10-15000 ppm), carbon dioxide, and propane. The first fraction contains dimethyl ether (not more than 100 ppm). It may contain a major portion of propane and a major portion of carbon dioxide. The second fraction may contain a major portion of propane.Preferred Properties: The second fraction has an average temperature of not more than 210 degrees F.    TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: The first separation step is carried out under at least 200 (preferably 250-290) psig or under less than 200 (preferably 120-180) psig in a distillation column. Water absorbent may be added to the distillation column at water absorbent to total effluent stream molar ratio of 4:1 - 1:5000. If effluent stream and first fraction contain carbon dioxide, the process may include reacting the first fraction with caustic medium under predetermined conditions to remove carbon dioxide from the first fraction. If the effluent stream and first fraction contain acetylene, the process may include reacting acetylene in first fraction with hydrogen and carbon monoxide under predetermined conditions to convert a portion of acetylene to ethylene.If the effluent stream, first fraction, and third fraction contain methane and acetylene, the process may include separating a portion of the third fraction into a fifth fraction containing a major portion of methane and a sixth fraction containing a major portion of acetylene, ethylene, and ethane; reacting acetylene in the sixth fraction with hydrogen and carbon monoxide under predetermined conditions to convert a portion of acetylene to ethylene, forming an acetylene-depleted stream comprising ethylene and ethane; and separating a portion of the acetylene-depleted stream into a seventh fraction containing a major portion of ethylene and an eighth fraction containing a major portion of ethane. If the effluent stream, first fraction, and fourth fraction contain propane, the process may include separating a portion of the fourth fraction into a ninth fraction containing a major portion of propylene and a tenth fraction containing a major portion of propane. A portion of the tenth fraction is recycled to the first separation unit. The process may include reacting the first fraction with water, acid-gas treating the first fraction, and drying the acid-gas treated first fraction; polymerizing ethylene from the seventh fraction; and polymerizing propylene from the ninth fraction.