Methane reaction with elemental sulfur

Methane reacts with elemental sulfur above 700 C or at lower temperatures in the presence of a catalyst to give good yields of CS2, a reaction that has been used for the commercial synthesis of the disulfide. n-Butane, however, gives alkenes, dienes and thiophene under similar conditions. 

Methane reacts with sulfur (an active nonmetal element of group 6A) at high temperatures to produce carbon disulfide. The reaction is endothermic, and an activation energy of approximately 160 KJ is required. Activated alumina or clay is used as the catalyst at approximately 675°C and 2 atmospheres. The process starts by vaporizing pure sulfur, mixing it with methane, and passing the mixture over the alumina catalyst. The reaction could be represented as ... 

Cespedes, C. and Vega, J.C. (1994) Reactions Of Dichloromethane With Thioanions. 1. Preparation Of Bis(N,N-Dialkylfhiocarbamoylthio) Methanes. Phosphorus, Sulfur Silicon Related Elements, 90(1—4), 155—158. 

Chlorine and sodium hydroxide are the main products of the industrial chlor-alkali electrolysis that is described as a process example in Section 6.19. Hydrochloric acid is produced by reaction from the elements H2 and CI2 or by the reaction of chloride salts such as, for example, NaCl or CaCl2, with sulfuric acid. Other important sources of HCl are industrial chlorination processes using CI2 as chlorination agent (e.g., chlorination of benzene to form chlorobenzene and HCl or the chlorination of methane to give chloromethane and HCl) or industrial dehydrochlorination processes (e.g., production of vinyl chloride and HCl from 1,2-dichloroethane). The main uses of hydrochloric acid are addition reactions to unsaturated compounds (by hydrochlorination or oxychlorination), formation of chlorine in the Deacon process, production of chloride salts from amines and other organic bases, dissolution of metals, regeneration of ion exchange resins, and the neutralization of alkaline products. 

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