Selective production of 4-ethyl phenol from low-temperature catalytic fast pyrolysis of herbaceous biomass

A new technique was proposed to selectively produce 4-ethyl phenol (4-EP) from low-temperature catalytic fast pyrolysis of certain herbaceous biomass, while 4-vinyl phenol (4-VP) could be selectively produced from non-catalytic fast pyrolysis process. In this study, Pd/SBA-15 catalysts were prepared, and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique was applied for both ex situ and in situ catalytic fast pyrolysis of bagasse . The results indicated the 4-EP could be selectively produced from both catalytic methods. During the ex situ catalytic pyrolysis process, the bagasse would decompose to form 4-VP which was then hydrogenated by the Pd/SBA-15 catalyst to be 4-EP. During the in situ catalytic pyrolysis process, the Pd/SBA-15 catalyst would catalyze the decomposition and hydrogenation of bagasse to directly produce 4-EP. Certain pyrolytic products would serve as the hydrogen-donors (H-donor) for the formation of 4-EP. The selectivity of the 4-EP from the ex situ catalytic process was a little better than that form the in situ catalytic process. The highest 4-EP yield from ex situ catalytic pyrolysis of bagasse was around 2.0   wt%, obtained at the pyrolysis temperature of 350   °C and catalyst-to-biomass ratio of 1.5.