Isomerization of 3-phenyl-1-propene (allylbenzene) over base catalysts

Several magnesium containing catalysts were tested for the 2-methyl-3-butyn-2-ol (MBOH) test reaction in a microcatalytic pulse reactor. All solids showed a selectivity close to 100% toward products formed on basic sites (mainly acetone and acetylene) in the 433-623 K range. However, no correlation was found between molar conversion per gram of catalyst and basic site density, determined by temperature-programmed desorption-mass spectrometry of CO2 as the probe molecule. In the search for a process that fulfilled such a correlation, a new model reaction for base catalysts was found: isomerization of 3-phenyl-1-propene (allylbenzene) to 1-phenyl-1-propene (cis + trans). Therefore, a good correlation (r = 0.986) between molar conversion (per gram of catalyst) and basic site density was obtained at 523 K for all catalysts tested. (C) 2002 Elsevier Science (USA).