Efficient Hydroliquefaction of Sawdust over a Novel Silica-Supported Monoclinic Molybdenum Dioxide Catalyst

Abstract

A novel synthesis method was developed to prepare a silica-supported monoclinic molybdenum dioxide (MoO 2 / SiO 2 ) catalyst via calcination of molybdenum disulfide (MoS 2 )/SiO 2 in N 2 flow with 0.1 vol % O 2 . MoO 2 /SiO 2 was employed as a catalyst for sawdust hydroliquefaction in ethanol at 320 °C under an initial H 2 pressure (IHP) of 2−6 MPa, and the bio-oil yield as high as 72.3% was obtained under an IHP of 6 MPa. The high catalytic activity of MoO 2 /SiO 2 should be attributed to the efficient cleavage of H 2 on the surface of highly dispersed MoO 2 , which shows an unusual metallic characteristic. The obtained bio-oil was analyzed with gas chromatography/mass spectrometry (GC/MS), and the main organic compounds detected by GC/ MS were phenolics and ethyl esters.

Ethanol: A Promising Green Solvent for the Deconstruction of Lignocellulose

“…[56] The experiments were carried out at temperatures ranging from 300 to 400 8C, initial hydrogen pressures varying from 2t o1 0MPa, and ar esidence time of 40 min without and with cocatalyst (1.2 wt %[ BMIM]Cl and 300 mgg À1 NiCl 2 ). [57] The crude bio-oil yield was 47 wt %a t3 20 8Cf or 40 min with an initial hydrogen pressure of 2MPa. The identified compounds in light and heavy bio-oils from the liquefaction of wood chips were mainly composed of esters, phenols, and carboxylic acids.…”

“…Thes ame group synthesized silicasupported monoclinic molybdenum dioxide (MoO 2 /SiO 2 )c atalyst for the liquefaction of wood in the form of sawdust in ethanol at 340 8Cf or 40 min. [57] The crude bio-oil yield was 47 wt %a t3 20 8Cf or 40 min with an initial hydrogen pressure of 2MPa. The use of the catalyst increased the bio-oil yield to about 60 wt %under same conditions.…”

“…No information was provided on whether these compounds were generated from catalytic or noncatalytic runs. [57] In av ery recent study,A kalin et al investigated the decomposition of beech wood in ethanol without andw ith the use of hydrated cerium(III) chloride at 300 8Cw ith residence times from 10 to 120 min. [57] The crude bio-oil yield was 47 wt %a t3 20 8Cf or 40 min with an initial hydrogen pressure of 2MPa.…”

“…Increasing the initial hydrogen pressure produces more active hydrogen, which results in more bio-oil and less bio-char. [57] In av ery recent study,A kalin et al investigated the decomposition of beech wood in ethanol without andw ith the use of hydrated cerium(III) chloride at 300 8Cw ith residence times from 10 to Figure 8. Liquefactiono fl ignocellulosic biomass in ethanol, depending on the temperature,h eating rate, and residence time.…”

Isolation and Identification of Six Difunctional Ethyl Esters from Bio-oil and Their Special Mass Spectral Fragmentation Pathways

“…Crude bio-oil, a black liquid directly obtained from biomass liquefaction or pyrolysis, is considered as the most promising substitute for fossil resources to produce transport fuels and chemicals. , However, the molecular compositions of the bio-oil are not yet fully understood, which severely limits its upgrading and value-added utilization, especially for production of valuable chemicals. Hence, understanding of bio-oil compositions at the molecular level is a crucial research goal for the scientists of chemistry, engineering, and bioenergy.…”