Kim et al. (1978)showed the bulk zinc iodide as good
catalyst for the production of butane and higher paraffins from
methanol. They conducted reactions at 200
C and 200 psi for a
period of 2 h. Methanol conversion was nearly complete (>99%) and
the catalyst actively produced mainly branched gasoline compounds of high octane number. Triptane (i.e. 2,2,3-trimethylbutane) was produced to selectivity closer to 50%. Similarly, lighter cracking species (i.e. with carbon number below
butane) were found only in trace quantities. The authors also
demonstrated zinc bromide to produced comparable activities
when the temperature was raised to the range of 220e245
C.
However, with zinc chloride triptane selectivity decays due to
higher reaction temperature required. Compounds of heteropoly
acids like the tiungstosilicic acid (TSA) and tungstophosphoric acid
(TPA) are another category of catalysts fully studied their behaviors
have been attributed to their Keggin structure and Brønsted acidity