Catalytic o-methylation of phenols and its application in converting crude phenols in a low-temperature coal tar to mesitol and durenol

The alkylation of phenols is an effective method for synthesizing alkylphenols as important chemicals and key building blocks. Herein, we investigated the methylation of phenols over Ni/Fe2O3 as the catalyst with CH3OH as methylating agent. The catalyst was characterized by laser ablation inductively coupled plasma mass spectrometry, BET surface area, transmission electron microscopy, NH3-temperature-programmed desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. The effects of catalyst composition and feed, reaction temperature and time, and recycling times of the catalyst on the o-methylation were systematically examined. As a result, only o-xylenols were detected and their relative contents increase with time under the optimized conditions. The methylation was also used to convert crude phenols extracted from a low-temperature coal tar to value-added chemicals, and consequently mesitol and durenol were produced in total yields up to 99%. Pure mesitol and durenol were obtained after elution and their structures are confirmed by multiple analyses.

Automated summary

The alkylation of phenols using Ni/Fe2O3 as the catalyst and CH3OH as methylating agent resulted in the detection of o-xylenols with a total yield of 99% under optimized conditions. Mesitol and durenol were obtained as value-added chemicals from crude phenols extracted from low-temperature coal tar, and their structures were confirmed through multiple analyses.