Halogen-containing hydrocarbons ratio

UOP s Isomar process (56,117—119) was originally developed to use dual-functional catalysts. The first-generation catalyst contained Pt and halogen on alumina. Operating conditions using this catalyst were 399°C 1.25 MPa 2 LHSV and H2/hydrocarbon ratio of 6 1. A Cg naphthene concentration of... 

The presence of halogen-containing radicals can play a substantial role in chemical processes in the atmosphere. Chlorine atoms react much faster with alkanes than OH, the effect of which has been clearly observed in the Arctic troposphere in connection with the sunrise ODEs (Ramacher et al., 1997 Ariya et al., 1997 Song and Carmichael, 1999). The high reactivity of chlorine with hydrocarbons may explain the relatively high CH2O volume mixing ratios of... 

Improvements in acrylonitrile yield are also reported with other vapor phase promoters. A patent assigned to Monsanto Co. (125) describes the use of sulfur and sulfur-containing compounds in the feed gas mixture for production of acrylonitrile or methacrylonitrile from propane or isobutane over metal oxide catalysts. Examples of effective sulfur-containing compounds include alkyl or dialkyl sulfides, mercaptans, hydrogen sulfide, ammonium sulfide, and sulfiir dioxide. Best results are apparently achieved using a molar ratio of sulfur (or sulfur compound) to hydrocarbon of 0.0005 1 to 0.01 1. Nitric oxide has also been examined as a gas-phase promoter for propane and isobutane ammoxidation (126). However, it does not appear to be as effective as halogen or sulfur. Selectivities to acrylonitrile from propane are only about 30% over an alumina-supported chromium-nickel oxide catalyst. 

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