On the mechanism of the conversion of methanol to 2,2,3-trimethylbutane (triptane) over zinc iodide.
Methanol is converted to a mixture of hydrocarbons by reaction with zinc iodide at 200 degrees C with one highly branched alkane, 2,2,3-trimethylbutane (triptane), being obtained in surprisingly high selectivity. Mechanistic studies implicate a two-stage process, the first involving heterogeneously catalyzed formation of a carbon-carbon-bonded species, probably ethylene, that undergoes homogeneously catalyzed sequential cationic methylation to higher hydrocarbons. The first stage can be bypassed by addition of olefins, higher alcohols, or arenes, which act as initiators. Rationales for the particular activity of zinc iodide and for the selectivity to triptane are proposed.
Bercaw
John E
JE
Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, California 91125, USA.
Diaconescu
Paula L
PL
Grubbs
Robert H
RH
Kay
Richard D
RD
Kitching
Sarah
S
Labinger
Jay A
JA
Li
Xingwei
X
Mehrkhodavandi
Parisa
P
Morris
George E
GE
Sunley
Glenn J
GJ
Vagner
Patrick
P