Heterogeneous catalysis is a promising technology for the valorization of renewable biomass to sustainable advanced fuels and fine chemicals. Porosity and nanostructure are the most versatile features of heterogeneous solid catalysts, which can greatly determine the accessibility of specific active sites, reaction mechanisms, and the selectivity of desirable products. Hence, the precise tuning of porosity and nanostructure has been a potential strategy towards developing novel solid catalysts with indispensable characteristics for efficient biomass valorization. Herein, we present a timely and comprehensive review of the recent advances in catalytic biomass conversions over microporous zeolites, mesoporous silicas, and nanostructured metals/metal oxides. This review covers the catalytic processing of both edible (lipids and starch) and non-edible (lignocellulose) biomass as well as their derived compounds, along with a systematic evaluation of catalyst reusability/kinetic/mechanistic aspects in the relevant processes. The key parameters essential for tailoring particle size, morphology, porosity, acid–base, and redox properties of solid catalysts are emphasized, while discussing the ensuing catalytic effects towards the selective conversion of biomass into desirable chemicals. Special attention has been drawn to understand the role of water in liquid phase biomass conversions as well as the hydrothermal stability and the deactivation of nanoporous catalysts. We believe this comprehensive review will provide new insights towards developing state-of-the-art solid catalysts with well-defined porosity and nanoscale properties for viable biomass conversion.

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Advances in porous and nanoscale catalysts for viable biomass conversion.

Metal-organic framework (MOF)-derived catalysts for fine chemical production

Catalytic conversion of renewable biomass to “green” chemicals and fuel additives has been extensively investigated in the past few decades. Interests on two top platform intermediates for biofuel production, i.e. levulinic acid (LA) and 5-hydroxymethylfurfural (HMF), have increased significantly. These two chemicals are generally produced from biomass through acid hydrolysis. This review summarizes the discoveries of the most recent studies on acid-catalyzed hydrolysis, including (i) biomass pretreatment, (ii) glucose production from cellulose hydrolysis, (iii) fructose formation from glucose isomerization, (iv) HMF formation from glucose/fructose dehydration and (v) LA production from HMF rehydration. Humins, the main byproducts, are also discussed in the aspect of their influence on the hydrolysis process, structure, formation mechanism, and applications.

From lignocellulosic biomass to levulinic acid: A review on acid-catalyzed hydrolysis

Catalytic Production of Value-Added Chemicals and Liquid Fuels from Lignocellulosic Biomass

Ionic liquid based pretreatment of lignocellulosic biomass for enhanced bioconversion.

Storage and oxidation stabilities of biodiesel derived from waste cooking oil

https://apps.dtic.mil/sti/pdfs/AD1103338.pdf

Flash points measurements and prediction of biofuels and biofuel blends with aromatic fluids

Humins are low-value-added byproducts from the biomass acid hydrolysis process. In the present work, humins were first employed as a phenol replacement for synthesis of modified phenol-formaldehyde adhesives through a two-step process. In this process, humins were first utilized to obtain alkaline soluble products, mainly consisting of phenolics, through a hydrothermal process. The obtained alkaline soluble products then reacted with phenol and formaldehyde to produce humin-phenol-formaldehyde adhesive (HPFA). The physicochemical properties of HPFA, including viscosity, bonding strength, pH, free formaldehyde level, free phenol level and solid content, met the requirements of the GB/T 14732-2006 Chinese National Standard.

Synthesis of Humin-Phenol-Formaldehyde Adhesive.

Knowledge of vapor pressure of organic pollutants is essential in predicting their fate and transport in the environment. In the present study, the vapor pressures of 12 halogenated polycyclic aromatic compounds (PACs), 9-chlorofluorene, 2,7-dichlorofluorene, 2-bromofluorene, 9-bromofluorene, 2,7-dibromofluorene, 2-bromoanthracene, 9-chlorophenanthrene, 9-bromophenanthrene, 9,10-dibromophenanthrene, 1-chloropyrene, 7-bromobenz[a]anthracene, and 6,12-dibromochrysene, were measured using the Knudsen effusion method over the temperature range of 301 to 464 K. Enthalpies and entropies of sublimation of these compounds were determined via application of the Clausius–Clapeyron equation. The data were also compared with earlier published literature values to study the influence of halogen substitution on vapor pressure of PACs. As expected, the halogen substitution decreases vapor pressure compared with parent compounds but does not necessarily increase the enthalpy of sublimation. Furthermore, the decrease of vapor pressure also depends on the substitution position and the substituted halogen, and the di-substitution of chlorine and/or bromine decreases the vapor pressure compared with single halogen-substituted polycyclic aromatic hydrocarbons. In addition, the enthalpy of fusion and melting temperature of these 12 PACs were determined using differential scanning calorimetry and melting point analysis. Environ. Toxicol. Chem. 2012;31:486–493. © 2011 SETAC

Jinxia Fu

Papers

From lignocellulosic biomass to levulinic acid: A review on acid-catalyzed hydrolysis

Storage and oxidation stabilities of biodiesel derived from waste cooking oil

Flash points measurements and prediction of biofuels and biofuel blends with aromatic fluids

Synthesis of Humin-Phenol-Formaldehyde Adhesive.

Thermochemical Properties and Phase Behavior of Halogenated Polycyclic Aromatic Hydrocarbons