Efficient Cu-based catalysts for the selective demethoxylation of guaiacols

Lignin is an attractive feedstock for low molecular weight biobased phenols using depolymerization strategies such as reductive catalytic fractionation or fast pyrolysis. Such often yield a product mixture enriched in lignin-derived monomers with methoxy substituents. Selective hydrodeoxygenation (HDO) effective methodology to demethoxylate these into valuable alkylated phenols. Here, we report the use of non-precious Cu based catalysts supported on SiO2, ZrO2, TiO2 (various forms), MoO3-ZrO2, and MoO3-TiO2 continuous fixed-bed reactor at elevated temperature pressure (300–360 °C, 10 bar) selective demethoxylation guaiacol. Among various catalysts, Cu/TiO2-P25 was found be highly stable catalyst (100 h stream) selectivity 87% demethoxylated compounds like phenol cresols guaiacol conversion 98%. A correlation between oxygen storage capacity support (TiO2-P25, TiO2-A HSA, TiO2-R, MoO3-TiO2) conversion, indicating that this property plays role cycle. Besides, 4-n-propylguaiacol realistic guaiacol-rich feed isolated from representative pyrolysis oil successfully demonstrated. guaiacols present were converted 81%.