Processes for Converting Benzene and/or Toluene Via Methylation

This disclosure provides improved processes for converting benzene/toluene via methylation with methanol/dimethyl ether for producing, e.g., p-xylene. In an embodiment, a process comprises contacting a methylation agent feed with an aromatic hydrocarbon feed in the presence of a methylation catalyst in a methylation reactor at increased pressure. Reduced methylation catalyst deactivation can be achieved with increased pressure in the methylation reactor.