ABSTRACT
Purification of methane is carried out at ambient or low temperature absorption and low-temperature fractionation. Methane is used as feedstock to produce many chemicals, including hydrogen cyanide, carbon disulfide, and chlorinated methanes. Methane must be essentially pure to prevent the formation of soot and poisoning the catalysts. The removal of higher hydrocarbons and desulfurization of the methane is necessary. The Sohio process provides strong competition against the synthesis of hydrogen cyanide from methane and ammonia especially since acrylonitrile is in high demands. The chlorinated methanes then are recovered in a similar manner to the methane chlorination method. Methyl chloride will react with benzene to form dimethyldibenzyl methane, an ingredient in the perfume industry because of its orange color. Chloromethanes are becoming less important because they are suspected carcinogens and some of their derivatives play a potential role in the depletion of the ozone layer. Multiple-halogen substituted methanes usually contain both chlorine and fluorine, better known as chlorofluorocarbons.
