destructive distillation

destructive distillation [di′strək·tiv dis·tə′lā·shən]

(organic chemistry)

Decomposition of organic compounds by heat without the presence of air.

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Destructive distillation

The primary chemical processing of materials such as wood, coal, oil shale, and some residual oils from refining of petroleum. It consists in heating material in an inert atmosphere at a temperature high enough for chemical decomposition. The principal products are (1) gases containing carbon monoxide, hydrogen, hydrogen sulfide, and ammonia, (2) oils, and (3) water solutions of organic acids, alcohols, and ammonium salts.

Crude shale oil may be obtained by destructive distillation of carboniferous shales. It may be subjected to a destructive, or coking, distillation to reduce its viscosity and increase its hydrogen content. Residual oils from petroleum refinery operations are subjected to coking distillation to reduce the carbon content. The coke is used for the manufacture of electrode carbon. The main product of the destructive distillation of wood is 40–45% charcoal used in metallurgical processes in which the low content of ash, sulfur, and phosphorus is important. See Coal chemicals