Highly Efficient Liquefaction of Woody Biomass in Hot-Compressed Alcohol−Water Co-solvents

Abstract

Alcohol (methanol or ethanol) and water showed synergistic effects on biomass direct liquefaction, and the 50 wt % co-solvent of either methanol-water or ethanol-water was found to be the most effective solvent for the liquefaction of eastern white pine sawdust. The 50 wt % aqueous alcohol at 300°C for 15 min produced a bio-oil yield at approximately 65 wt % and a biomass conversion of >95%. At a temperature higher than 300°C, conversion of bio-oil to char was significant by repolymerization. The Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) analyses of the obtained bio-oils confirmed the presence of primarily phenolic compounds and their derivatives (such as benzenes), followed by aldehyde, long-chain (and cyclic) ketone and alcohol, ester, organic acid, and ether compounds. Gel permeation chromatography (GPC) results suggested that hotcompressed ethanol as the liquefaction solvent favored lignin degradation into monomeric phenols. The X-ray diffraction (XRD) patterns of sawdust before and after the liquefaction displayed that the cellulosic structure of the feedstock was completely converted into amorphous carbon at around 300°C and into crystalline carbon at about 350°C.

Preparative Aspects of Supported Ni2P Catalysts for Reductive Upgrading of Technical Lignin to Aromatics

“…Huang et al found that carrying out a similar lignin depolymerization process in ethanol instead of methanol using a Cu-Mg-Al mixed oxide catalyst resulted in higher aromatics yield and less char by-product [8][9][10]. The better performance in ethanol is in keeping with an earlier report by Cheng et al [16].…”

“…This was confirmed in the work of Huang et al [9]. Overall, the aromatic monomers yields are higher when depolymerization of lignin is carried out in ethanol than in methanol [16,19,20]. Ethanol has several functions: it dissolves lignin, it chemically protects the useful lignin fragments against undesired repolymerization by alkylation of aromatic rings and phenolic groups and it is a source of hydrogen to facilitate the hydrogenative removal of oxygen functionalities from the fragments [8].…”

Aloe Vera Rind Nanofibers: Effect of Isolation Process on the Tensile Properties of Nanofibre Films

“…Both AV rind and AV pulp fibers had a high amount of ash that was slightly lower than ash content (8.89 %) in AV rind with cuticle (Cheng et al 2014) but much higher than 0.4% in wood (Cheng et al 2010). The AV rind without cuticle presented a high amount of α-cellulose of 50.05 % that was even higher than 40.2% in wood (Cheng et al 2010). The α-cellulose identified in AV pulp fibers was remarkably increased to 77.22%.…”

Direct Liquefaction of Bamboo in Ethanol-Phenol Co- Solvent

“…Meanwhile, the absorption profiles between 690 cm -1 and 930 cm -1 implied the presence of phenyl rings and substituted phenyl rings (Cheng et al 2010). The peak at 1050 cm -1 appeared in the absorption profile of bamboo and solid residue, which could be C-O connected with hydroxyl groups and were dehydrated after liquefaction.…”