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Highlights: [•] Quantitative relationship between biomass components and pyrolysis oxygenates. [•] Interaction between biomass components affect formation of certain oxygenates. [•] Pretreatment and plant genomics could play a role in improving bio-oil quality. [ABSTRACT FROM AUTHOR]

Highlights: [•] Highly selective process for the production of simple phenols. [•] TiO2 defunctionalized monomeric phenolics from lignin. [•] Over 95% conversion of monomeric phenolics is attainable. [•] Catechols were the most reactive monomeric phenolic. [•] Anatase TiO2 performed much better than rutile TiO2. [Copyright &y& Elsevier]

We report on a new pyrolytic pathway for biomass conversion to hydrocarbon fuel precursors. The process entails the conversion of multifunctional oxygenates generated from biomass pyrolysis over a metal oxide catalyst into ketonic-rich monofunctional molecules suitable for making hydrocarbon fuel components for gasoline, diesel, and jet fuel. A number of catalysts were explored, for example, anatase TiO2 nanorods, CeOx–TiO2 mixed oxides, pure CeO2, ZrO2, and MgO. Under pyrolysis conditions, ceria-based catalysts were effective in the conversion of hydroxy-carbonyls, anhydrosugars, and carboxylic acids into acetone, 2-butanone, pentanones, C6/C7 ketones, cyclopentanone, and 2-cyclopentenones. The highest carbon yield (23.5%) of ketonic precursors was achieved on the pure CeO2. [ABSTRACT FROM AUTHOR]

Integration of biomass pretreatment with pyrolysis offers an opportunity to improve end-product quality and conversion efficiency. In this study, sugar maple ( Acer saccharum ) was subjected to both hot-water extraction (HWE) at 160 °C (at residence times of 0.5 h, 1.0 h, and 2.0 h) and electron beam (EB) irradiation at a dose of 1000 kGy. Pyrolysis studies were then conducted on all the treated samples at 550 °C using a bench scale pyroprobe-gas chromatography–mass spectrometry (Py-GC/MS). The HWE samples were selected for further evaluation in catalytic pyrolysis using HZSM-5 catalysts for the production of aromatic hydrocarbons. Analysis of the hot-water treated sample at 160 °C for 2 h showed that HWE increased the volatile mater and decreased the fixed carbon and ash contents; also the glucan content increased by 24% and the xylan decreased by 54%. Derivative thermogravimetry (DTG) analysis indicated that EB irradiation reduced the crystallinity of the sugar based polymers while HWE solubilized the hemicellulose fraction. The pyrolysis results showed that EB irradiation increased the formation of furanic aldehydes (furfural and 5-hydroxymethylfurfural (5-HMF)) and decreased hydroxyacetaldehyde (HAA) and levoglucosan (LG). By contrast, HWE increased the yield of LG, HAA, 5-HMF and furfural; but, decreased the yields of acetic acid (HAc), hydroxyacetone, and other ketones. For the HWE-2 h sample, LG formation increased from 4.45 wt.% to 11.57 wt.% and HAc decreased from 4.87 wt.% to 2.40 wt.%. Catalytic pyrolysis of HWE samples with HZSM-5 zeolite showed that the carbon yields of monoaromatic hydrocarbons increased. HWE treatment at 160 °C for 2 h increased the yield of benzene by 46%, toluene by 35% and xylene by 26%. Pyrolysis-TGA also indicated that HWE decreased the formation of char/coke. Overall, the reduction in the formation of acids and ketones caused by HWE suggest that it could be used to improve bio-oil quality in non-catalytic pyrolysis whilst the increase in the yield of monoaromatic hydrocarbons indicate that HWE could be used to enhance the carbon efficiency in catalytic pyrolysis. [ABSTRACT FROM AUTHOR]