Premium
Hydrogenolysis of alkyl‐substituted adamantanes, diamantanes, and triamantanes in the gas phase on a nickel‐alumina catalyst
Author(s) -
Grubmüller Peter,
Maier Wilhelm F.,
von Ragué Schleyer Paul,
McKervey M. Anthony,
Rooney John J.
Publication year - 1980
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19801130533
Subject(s) - chemistry , diamondoid , alkyl , alkylation , hydrogenolysis , nickel , catalysis , substituent , steric effects , adamantane , bond cleavage , yield (engineering) , homolysis , hydrocarbon , hydrogen , photochemistry , medicinal chemistry , organic chemistry , molecule , thermodynamics , radical , physics
Dealkylation of several alkyladamantanes, diamantanes, and triamantanes has been observed in the gas phase with hydrogen at atmospheric pressure on a 30% nickel‐alumina catalyst. Yield‐temperature profiles show that the optimum temperature for obtaining the pure parent compound in high yield can be as low as 215 °C. The ease of removal of an alkyl substituent depends on whether it is secondary or tertiary on the diamondoid nucleus. Rupture of the diamondoid skeleton requires much higher temperatures (over 280 °C) than dealkylation. The hydrogenolytic degradation of diamantane to adamantane was examined with the aid of molecular mechanics calculations; likely pathways for CC bond cleavage were deduced which are consistent with the several intermediates detected experimentally. The mechanism of dealkylation is discussed in terms of steric and thermodynamic factors and the nature of possible surface intermediates.