999-06-4Relevant articles and documents
Catalytic distillation process for primary haloalkanes
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Page/Page column 9-10, (2012/02/17)
A process for making primary haloalkanes by catalytic distillation of internal haloalkanes which comprises a) introducing an internal haloalkane feed into a catalytic distillation column; b) isomerizing at least a portion of the internal haloalkane feed in the presence of an internal haloalkane isomerization catalyst at a temperature at or above the boiling point of the internal haloalkanes and below the temperature and pressure at which hydrogen halide is formed to form primary haloalkanes; and removing the primary haloalkanes from the catalytic distillation column.
Highly efficient oxidative bromination of alkanes with the HBr-H 2O2 system in the presence of catalyst
Li, Yujin,Ju, Jie,Jia, Jianhong,Sheng, Weijian,Han, Liang,Gao, Jianrong
experimental part, p. 2428 - 2432 (2011/10/03)
Various cycloalkanes and straight-chain alkanes were efficiently brominated with an aqueous HBr-H2O2 system. This oxidative brominating process was promoted by catalysis and irradiation with light. The cycloalkanes were converted to the corresponding bromo-cycloalkanes in moderate yields and the straight-chain alkanes produced dominantly secondary bromides. This simple but effective bromination method of alkanes is characterized by high atom efficiency, inexpensive reagents and the absence of organic waste, which make it a good alternative to the existing method for Ci￡H activation through bromination. A simple, effective, environmentally friendly method was researched for bromination of alkanes in good yield with HBr as the origin of bromine.
Halide assisted addition of hydrogen halides to alkenes
Weiss, Hilton M.,Touchette, Kim M.
, p. 1517 - 1522 (2007/10/03)
The addition of 0.1 M quaternary ammonium halide to a solution of 20% trifluoroacetic acid in methylene chloride causes a large rate increase in the reaction of simple alkenes leading to a mixture of alkyl halides and trifluoroacetates. The mechanism is proposed to involve a halide assisted protonation of the alkene which produces a carbocation intermediate sandwiched between the attacking halide ion and the trifluoroacetate ion. At higher concentrations of halide ion, the proton donating ability of the solution decreases, slowing the reaction and increasing the efficiency of cation capture by the halide ion. This leads to a greater proportion of unrearranged halide product. At the highest concentration of halide ion, cation rearrangement is virtually eliminated.
