5-Hydroxymethylfurfural (HMF) as a building block platform: Biological properties, synthesis and synthetic applications

Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine-tuning of multiple "upstream" (i.e., lignin bioengineering, lignin isolation and "early-stage catalytic conversion of lignin") and "downstream" (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a "beginning-to-end" analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis.

Pyrolysis is one of the thermochemical technologies for converting biomass into energy and chemical products consisting of liquid bio-oil, solid biochar, and pyrolytic gas. Depending on the heating rate and residence time, biomass pyrolysis can be divided into three main categories slow (conventional), fast and flash pyrolysis mainly aiming at maximising either the bio-oil or biochar yields. Synthesis gas or hydrogen-rich gas can also be the target of biomass pyrolysis. Maximised gas rates can be achieved through the catalytic pyrolysis process, which is now increasingly being developed. Biomass pyrolysis generally follows a three-step mechanism comprising of dehydration, primary and secondary reactions. Dehydrogenation, depolymerisation, and fragmentation are the main competitive reactions during the primary decomposition of biomass. A number of parameters affect the biomass pyrolysis process, yields and properties of products. These include the biomass type, biomass pretreatment (physical, chemical, and biological), reaction atmosphere, temperature, heating rate and vapour residence time. This manuscript gives a general summary of the properties of the pyrolytic products and their analysis methods. Also provided are a review of the parameters that affect biomass pyrolysis and a summary of the state of industrial pyrolysis technologies.

Lignocellulosic biomass pyrolysis: A review of product properties and effects of pyrolysis parameters

Trends in bioconversion of lignocellulose: Biofuels, platform chemicals & biorefinery concept

Hemicelluloses for fuel ethanol: A review.

A review and perspective of recent bio-oil hydrotreating research

Wet algae slurries can be converted into an upgradeable biocrude by hydrothermal liquefaction (HTL). High levels of carbon conversion to gravity separable biocrude product were accomplished at relatively low temperature (350 °C) in a continuous-flow, pressurized (sub-critical liquid water) environment (20 MPa). As opposed to earlier work in batch reactors reported by others, direct oil recovery was achieved without the use of a solvent and biomass trace components were removed by processing steps so that they did not cause process difficulties. High conversions were obtained even with high slurry concentrations of up to 35 wt.% of dry solids. Catalytic hydrotreating was effectively applied for hydrodeoxygenation, hydrodenitrogenation, and hydrodesulfurization of the biocrude to form liquid hydrocarbon fuel. Catalytic hydrothermal gasification was effectively applied for HTL byproduct water cleanup and fuel gas production from water soluble organics, allowing the water to be considered for recycle of nutrients to the algae growth ponds. As a result, high conversion of algae to liquid hydrocarbon and gas products was found with low levels of organic contamination in the byproduct water. All three process steps were accomplished in bench-scale, continuous-flow reactor systems such that design data for process scale-up was generated.

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Process development for hydrothermal liquefaction of algae feedstocks in a continuous-flow reactor

The reactivity of monosaccharides, furfural, and 5-hydroxymethyl-2-furfural (HMF) in the presence of a Bronsted acid (added as H(2)SO(4)) in the ionic liquid 1-butyl-3-methylimidazolium chloride (BMImCl) is investigated at 120 °C. Fructose is converted much faster than mannose, glucose, and xylose and yields HMF with high selectivity, even in the absence of acid. Conversion of mannose, glucose, and xylose involves more complex reaction networks. Only small amounts of furfural and HMF are converted in the absence of other reactants but both compounds are consumed when monosaccharides and their degradation products are present. Acid-catalyzed degradation reactions also lead to the formation of solid residues (humins).

Acid‐Catalyzed Conversion of Sugars and Furfurals in an Ionic‐Liquid Phase

Catalytic hydroprocessing has been applied to the fast pyrolysis liquid product (bio-oil) from softwood biomass in a bench-scale continuous-flow fixed-bed reactor system. The intent of the research was to develop process technology to convert the bio-oil into a petroleum refinery feedstock to supplement fossil energy resources and to displace imported feedstock. This paper is focused on the process experimentation and product analysis. A range of operating parameters, including temperature from 170 or 250 to 400 °C in the two-stage reactor and flow rate of 0.19 liquid hourly space velocity, was tested with bio-oil derived from pine wood. Times on stream of up to 90 h were evaluated, and losses of catalyst activity were assessed. Product yields of 0.35–0.45 g of oil product/g of dry bio-oil feed with hydrogen consumptions from 342 to 669 L/L of bio-oil feed were measured. Analyses determined that product oils with densities of 0.82–0.92 g/mL had oxygen contents of 0.2–2.7 wt % and total acid number (TAN) o...

Catalytic Hydroprocessing of Fast Pyrolysis Bio-oil from Pine Sawdust

A comprehensive study of the acid hydrolysis of the softwood species, Loblolly pine (Pinus taeda), using different hydrolysis conditions is presented. The effect of the type of acid, pH, reaction temperature, and reaction time on hydrolysis products such as monosaccharides (mannose, glucose, galactose, xylose, and arabinose) and the subsequent degradation products, 5-hydroxymethyl-2-furaldehyde (HMF) and 2-furaldehyde (furfural) is reported using a batch reactor. Trifluoroacetic acid (TFA) is found to yield the highest amount of overall soluble monosaccharides (∼70% yield from the hemicelluloses fraction) at 150 °C at pH 1.65. The mineral acids (HCl, H2SO4, HNO3, and H3PO4) gave a slightly lower yield of monosaccharides from hydrolyzed hemicellulose (∼60%). At 200 °C, cellulose is hydrolyzed by the mineral acids as evidenced by higher levels of solid dissolution and higher soluble hexose (relative to pentose) yields. Larger amounts of degradation products are also noted at higher temperatures. Furthermore...

Mariefel V. Olarte

Papers

A review and perspective of recent bio-oil hydrotreating research

Process development for hydrothermal liquefaction of algae feedstocks in a continuous-flow reactor

Acid‐Catalyzed Conversion of Sugars and Furfurals in an Ionic‐Liquid Phase

Catalytic Hydroprocessing of Fast Pyrolysis Bio-oil from Pine Sawdust

Dilute Acid Hydrolysis of Loblolly Pine: A Comprehensive Approach