Catalytic Pyrolysis of Lignin Model Compound (Ferulic Acid) over Alumina: Surface Complexes, Kinetics, and Mechanisms

Tetiana Kulik,Borys Palianytsia,Mats Larsson,Mykola Ilchenko,Nataliia Nastasiienko

doi:10.3390/catal11121508

Abstract

Studies of the thermochemical properties of the important model compound of lignin-ferulic acid (FA) and its surface complexes are substantial for developing technologies for catalytic pyrolysis of renewable biomass into biofuels and lignin-derived chemicals as well as for bio-oil upgrading. In this work, the catalytic pyrolysis of ferulic acid over alumina was studied by temperature-programmed desorption mass spectrometry (TPD MS), in situ FT-IR spectroscopy, thermogravimetric analysis, and DFT calculations. We established that both the carboxyl group and the active groups (HO and CH3O) of the aromatic ring interact with the alumina surface. We calculated the kinetic parameters of formation of the main products of catalytic pyrolysis: 4-vinylguaiacol, guaiacol, hydroxybenzene, benzene, toluene, cresol, naphthalene, and PACs. Possible methods of their forming from the related surface complexes of FA are suggested.

Highlights

Concerns for climate change, high oil prices, depletion of fossil fuels, energy security, and technological diversification of energy sources are driving increasing demand on renewable energy sources
As a result of the study, we found that the interaction of various active groups of the acid with the alumina surface led to the formation of different carboxylate complexes with a bidentate chelate and a monodentate structure as well as phenolate complexes
Analysis of the thermogravimetric data (Table 3) showed that 85% of the ferulic acid (FA) was converted into volatile products and 15% was converted into char on the surface

Summary

Introduction

Concerns for climate change, high oil prices, depletion of fossil fuels, energy security, and technological diversification of energy sources are driving increasing demand on renewable energy sources. Bio-based fuels, chemicals, and materials are expected to be an essential part of the future bioeconomy. Rising demands for these renewable commodities during post-COVID recovery confirms these expectations. The cost of 2G biomass is low, as was shown by. Wit and Faaij [8], where costs for agricultural waste are 1–7 € GJ−1 and for forest residues are 2–4 € GJ−1. The main components of pyrolysis oils [1,2,3,4,5,6,7,9,10,11] are carboxylic acids, phenols, aldehydes, ketones, alcohols, furans, phenols, alkanes, etc

Methods

Results

Conclusion