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Öğe Ethanol: A Promising Green Solvent for the Deconstruction of Lignocellulose(Wiley-V C H Verlag Gmbh, 2018) Tekin, Kubilay; Hao, Naijia; Karagoz, Selhan; Ragauskas, Arthur J.Growing energy demand, environmental impact, energy security issues, and rural economic development have encouraged the development of sustainable renewable fuels. Nonfood lignocellulosic biomass is a suitable source for sustainable energy because the biomass feedstocks are low cost, abundant, and carbon neutral. Recent thermochemical conversion studies are frequently directed at converting biomass into high-quality liquid fuel precursors or chemicals in a single step. Supercritical ethanol has been selected as a promising solvent medium to deconstruct lignocellulosic biomass because ethanol has extraordinary solubility towards lignocellulosic biomass and can be resourced from cellulosic ethanol facilities. This review provides a critical insight into both catalytic and noncatalytic strategies of lignocellulose deconstruction. In this context, the supercritical ethanol deconstruction pathways are thoroughly reviewed; GC-MS, 1D and 2D NMR spectroscopy, and elemental analysis strategies towards liquid biomass deconstruction products are also critically presented. This review aims to provide readers a broad and accurate roadmap of novel biomass to biofuel conversion techniques.Öğe One-pot transformation of lignocellulosic biomass into crude bio-oil with metal chloride catalyst via hydrothermal and supercritical ethanol processing(Amer Chemical Soc, 2019) Hao, Naijia; Ragauskas, Arthur; Alper, Koray; Karagoz, Selhan; Tekin, Kubilay[No abstract available]Öğe One-pot transformation of lignocellulosic biomass into crude bio-oil with metal chlorides via hydrothermal and supercritical ethanol processing(Elsevier Sci Ltd, 2019) Hao, Naijia; Alper, Koray; Tekin, Kubilay; Karagoz, Selhan; Ragauskas, Arthur J.Grape seeds were deconstructed in both hydrothermal and supercritical ethanol media with a combination of two metal chlorides (TiCl4:MgCl2) to produce bio-oils. The use of metal chloride additives in supercritical ethanol achieved the highest bio-oil yield of 49.2 wt% (300 degrees C, 30 min). Both the hydrothermal and supercritical ethanol deconstruction with the additives (TiCl4:MgCl2 = 4 mmol:4mmol) produced the bio-oils with a higher heating value (HHV) of 35 MJ/Kg. Gas chromatography-mass spectrometry (GC-MS) analysis of the bio-oils showed that the major products in bio-oils from the hydrothermal deconstruction were acids while the majority products in bio-oils form the supercritical ethanol deconstruction were esters. Nuclear magnetic resonance (NMR) data of the bio-oils suggested that both hydrothermal and supercritical ethanol deconstruction with metal chlorides significantly reduced the non-condensed OH and oxygenated lignin sub-units in bio-oils; while only supercritical ethanol deconstruction with metal chlorides reduced the aliphatic OH and O-alkylated structures in bio-oils.Öğe One-step transformation of biomass to fuel precursors using a bi-functional combination of Pd/C and water tolerant Lewis acid(Elsevier Sci Ltd, 2020) Hao, Naijia; Alper, Koray; Patel, Himanshu; Tekin, Kubilay; Karagoz, Selhan; Ragauskas, Arthur J.Direct one-pot transformation of lignocellulosic biomass has been developed as an effective and sustainable strategy to produce fuel blend stocks and high value chemical building blocks. In this wok, a bi-functional catalyst system consisting of palladium supported on carbon (Pd/C) and metal triflates (i.e., Sm(OTf)(3), La(OTf)(3), and Cu(OTf)(3) were shown to promote the biomass liquefaction in both hot-compressed water and supercritical ethanol medium, converting fir wood into oxygenated compounds. The highest bio-oil yield from hydrothermal liquefaction (HTL) was 10.47 wt% over Pd/C whereas the highest bio-oil yield of 49.71 wt% was achieved from supercritical ethanol liquefaction (SCEL) over the bi-functional catalyst system of Pd/C and La(OTf)(3). Higher heating values, carbon recovered values and boiling point distributions were further determined for elucidating the physical properties of the bio-oils. Gas chromatography mass spectrometry (GC-MS) analysis of the bio-oils revealed the chemical composition of the bio-oils. Substituted phenols and cyclopentenone/cyclopentanone type compounds consisted of more than 60 area% of the total products from HTL, whereas phenol and esters represented the major products from SCEL. The major reaction pathways are proposed based on the GC-MS results, which include depolymerizaton, isomerization, dehydration, condensation, and hydrogenation.
