(544ef) Equilibrium Analysis of Methylbenzene Intermediates for a Methanol-to-Olefins Process
We carried out the MTO reaction over ZSM-5 in a fixed bed quartz reactor, and methanol was carried out with nitrogen. The products were analyzed with a chromatograph from Agilent Technologies. FID detectors were used to get the concentration of the higher olefins for its higher sensitivity for hydrocarbons.
Some important reaction in this system, such as cracking, isomerization and methylation, were reviewed. We calculated ÎG of some typical reactions, showed in Figure 1. The energy change of cracking and isomerization is obviously higher than methylation and chain growth, indicating that the whole methanol-to-olefins process is controlled by cracking and isomerization. However, the isomerization is often limited by steric factors. Therefore in zeolite micropores, cracking becomes the only factor which controls the whole process.