Methane activation over zeolite catalysts: The methylation of benzene

Further evidence for the oxidative methylation of benzene with methane over zeolite catalysts

“…Our recent investigations [6,7] have also indicated that the addition of methanol to the batch reactor containing benzene, methane and catalyst which had been totally purged of oxygen gave conversions and product selectivities similar to those found in the presence of oxygen. For example, addition of 1.2 mole% methanol gave 0.75% conversion of benzene to toluene, and 10.4 mole% methanol gave 5.6% conversion of benzene.…”

“…Blank runs with catalyst but involving 6.9 MPa nitrogen or 6.9 MPa hydrogen in place of methane were also carried out. Other details of the experimental procedures for the catalytic experiments are similar to those published recently [6].…”

“…In other words, the reaction products and unreacted benzene were not recovered after reaction by dissolution in dichloromethane as was done in standard batch reaction runs [6]. Hence, autoclave…”

“…It has now been shown by our recent investigations [6,7] that the presence of oxygen is required for the production of the methylated products in the methylation of benzene with methane at 400 ºC over ZSM-5 catalysts in a high pressure batch reactor. In these studies, it was also observed that when catalyst was excluded and the batch reactor was flushed with oxygen prior to adding methane, methanol was the major product obtained (about 86 % selectivity [7]).…”

“…For example, addition of 1.2 mole% methanol gave 0.75% conversion of benzene to toluene, and 10.4 mole% methanol gave 5.6% conversion of benzene. It has been demonstrated too that there is no significant effect on benzene conversion and selectivity to toluene and other aromatic products on increasing the reaction time beyond 2 hours [6,7]. This cannot be due to catalyst poisoning (e.g.…”