Hydrogen hydrocarbons with acid catalysts

Concurrently, a series of papers began to appear on the isomerization and hydrogen-exchange reactions of hydrocarbons with acid catalysts. Over slightly hydrated aluminum bromide at room temperature propane containing carbon-13 at one end (C Hq-I-C )was found to isomerize toward a statistical mixture with... 

Many theories have been proposed but three have received considerable attention Whitmore s carbonium ion theory (26) postulates that a carbonium ion (positive hydrocarbon ion) adds to an olefin to form a higher molecular weight carbonium ion which then yields the olefin polymer by elimination of a proton (H+). With acid catalysts—for example, sulfuric acid—the initial carbonium ion is formed by addition of a hydrogen ion from the acid to the extra electron pair in the double bond of the olefin. A second pro-... 

Nitriles. Nitriles can be prepared by a number of methods, including ( /) the reaction of alkyl haHdes with alkaH metal cyanides, (2) addition of hydrogen cyanide to a carbon—carbon, carbon—oxygen, or carbon—nitrogen multiple bond, (2) reaction of hydrogen cyanide with a carboxyHc acid over a dehydration catalyst, and (4) ammoxidation of hydrocarbons containing an activated methyl group. For reviews on the preparation of nitriles see references 14 and 15. 

Dichloroethane is produced commercially from hydrogen chloride and vinyl chloride at 20—55°C ia the presence of an aluminum, ferric, or 2iac chloride catalyst (8,9). Selectivity is nearly stoichiometric to 1,1-dichloroethane. Small amounts of 1,1,3-tfichlorobutane may be produced. Unreacted vinyl chloride and HCl exit the top of the reactor, and can be recycled or sent to vent recovery systems. The reactor product contains the Lewis acid catalyst and must be separated before distillation. Spent catalyst may be removed from the reaction mixture by contacting with a hydrocarbon or paraffin oil, which precipitates the metal chloride catalyst iato the oil (10). Other iaert Hquids such as sdoxanes and perfluorohydrocarbons have also been used (11). 

Direct Metal Reaction. The DMR process is carried out over a catalyst with fatty acids ia a melted state or dissolved ia hydrocarbons. The acid reacts directiy with the metal, suppHed ia a finely divided state, produciag the metal soap and ia some cases hydrogen. Catalysts iaclude water, aUphatic alcohols, and low molecular-weight organic acids. 

In the Fischer-Tropsch process, carbon monoxide reacts with hydrogen in the presence of a solid catalyst, with the formation of a mixture of hydrocarbons. The composition of the product varies considerably with the catalyst and the operating conditions. The mixture may include (in addition to hydrocarbons) alcohols, aldehydes, ketones, and acids. 

Dining chlorination of hydrocarbons with Lewis acid catalysis, the catalyst must be premixed with the hydrocarbon before admission of chlorine. Addition of catalyst to the chlorine-hydrocarbon mixture is very hazardous, causing instantaneous release of large volumes of hydrogen chloride. 

Detal [Detergent alkylation] A process for making detergent alkylate, i.e., alkyl aromatic hydrocarbons such as linear alkyl benzenes, as intermediates for the manufacture of detergents, by reacting C10-C13 olefins with benzene in a fixed bed of an acid catalyst. Developed by UOP and CEPSA as a replacement for their Detergent Alkylate process, which uses liquid hydrogen fluoride as the catalyst. Demonstrated in a pilot plant in 1991 and first commercialized in Canada in 1996. Offered by UOP. 

For metal catalysts used for hydrogenations and, in combination with acid functions, in hydrocarbon reforming reactions, the advantage of nano-size metal particles has been well known. More recently it has been demonstrated that metals on... 

A more detailed interpretation of the chemistry of catalytic cracking was based on studies with pure hydrocarbons.121-123 A simplified summary put forward by Heinemann and coworkers123 (Fig. 2.1) shows how Cg open-chain and cyclic alkanes are transformed to benzene by the action of both the hydrogenating (metal) and acidic (halogenated alumina) functions of the catalyst. 

Traditionally, solid acidic catalysts are applied in industry for the oligomerization of butenes and are still studied. MTS-type aluminosilicates,522 a NiCsNaY zeolite,523 and a silica-alumina containing 13% alumina524 proved to be active and selective catalysts. Moreover, deactivation rates of these catalysts are also favorable. Sulfated zirconia promoted with Fe and Mn was active and selective to yield primarily dimethylbutene isomers under supercritical conditions.525 A small amount of water improved productivity and decreased deactivation. A study showed that the blending octane number of Cg hydrocarbons is directly linked to the number of allylic hydrogens in the molecules.526... 

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