1985-59-7Relevant articles and documents
Surface-Mediated Reactions. 6. Effects of Silica Gel and Alumina on Acid-Catalyzed Reactions
Kropp, Paul J.,Breton, Gary W.,Craig, Stephen L.,Crawford, Scott D.,Durland, William F.,et al.
, p. 4146 - 4152 (2007/10/02)
Absorption of a variety of acids to chromatographic silica gel results in substantial enhancement of their catalytic activity-affording easily prepared, environmentally benign heterogeneous acids that are highly effective in mediating a number of processes.This was shown for the isomerization of allene 1 and dimerization of the corresponding 1,3-diene 2; cyclization of (R)-citronellal (5), the related diester 10, and 1,5-cyclooctadiene (15); Rupe rearrangement of alkynol 18; and Friedel-Crafts cyclodehydration of alcohols 21.By contrast, commercially available Nafion-H was significantly less effective as a heterogeneous acid catalyst.Chromatographic alumina displayed enigmatic behavior, showing enhanced acidity on the adsorption of HCl but little or no acidity on the adsorption of a variety of other types of acid.The results are discussed in terms of the surface structures of silica gel and alumina.
Electrosynthesis of Organic Compounds. V. Electrochemical Reduction of Selected Arylalkyl Halides
Ismail, M. T.,Abdel-Wahab, A. A.,Mohamed, O. S.,Khalaf, A. A.
, p. 1174 - 1176 (2007/10/02)
Electrochemical reductions of some selected arylalkyl halides were carried out in methanol containing 0.1 mol*l-1 Ba(ClO4)2 on different cathodes (Hg, Zn).The compounds investigated were benzyl bromide (1); phenylethyl bromide (2); 3-phenylpropyl bromide (3); 4-phenylbutyl chloride (4); 1-methyl-3-phenylpropyl chloride (5); 1,1-dimethyl-3-phenylpropyl chloride (6) and 1,1-dimethyl-4-phenylbutyl chloride (7).The isolated products were found to include hydrogen abstraction, dehydrogenation, dimerization as well as cyclization products.Suitable mechanism involving the formation of intermediate carbanions and of free radicals was suggested to explain the results.Also, polarization curves for the compounds investigated were measured and the reduction half-wave potentials were determined.
