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Öğe Deconstruction of lignocellulosic biomass with hydrated cerium (III) chloride in water and ethanol(Elsevier Science Bv, 2017) Akalin, Mehmet K.; Das, Parthapratim; Alper, Koray; Tekin, Kubilay; Ragauskas, Arthur J.; Karagoz, SelhanLignocellulosic biomass was decomposed to produce crude bio-oil in water and ethanol using hydrated cerium (III) chloride as a catalyst. Use of the catalyst affected not only the yield of crude bio-oil but also the composition of bio-crude for both water and ethanol. The catalyst had a detrimental effect on the crude bio-oil yields obtained from water processing for all runs. However, in ethanol, use of the catalyst improved the crude bio-oil yields in all tested runs. The solid residue yields decreased with the catalyst use in the runs with water but increased in all studies with ethanol, except those with the shortest tested residence time of 10 min. The highest crude bio-oil yield of 48.2 wt% was obtained at 300 degrees C using 5 mmol of hydrated cerium (III) chloride at a residence time of 90 min in ethanol. The heating values of the crude bio-oils increased with the catalyst use for both water and ethanol processing. The highest heating value of 33.3 MJ kg(-1) was obtained with hydrated cerium (III) chloride at 300 degrees C and a residence time of 120 min.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 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.Öğe Sustainable energy and fuels from biomass: a review focusing on hydrothermal biomass processing(Royal Soc Chemistry, 2020) Alper, Koray; Tekin, Kubilay; Karagoz, Selhan; Ragauskas, Arthur J.Fossil fuels are being replaced with renewable energy resources (biomass and biomass waste, solar, geothermal, wind,etc.) to ensure sustainable development, reduce the dependence on fossil fuels, address environmental challenges including climate change. Today, biomass produces 5 x 10(19)kJ of energy/year, which corresponds to 10% of the annual global energy consumption. Considering the variety of biomass resources, this value is predicted to reach 150 x 10(19)kJ by 2050. Biomass may become even more important for use as an energy resource and chemical raw material in the 21st century. Hydrothermal biomass conversion stands out as a promising and alternative technology. Methods such as traditional gasification and pyrolysis require dry biomass. Hydrothermal techniques have been developed to eliminate the cost and time required for drying biomass. The purpose of this process is to decompose biomass with a high moisture content into small molecules and reduce its oxygen content to obtain liquid fuels or valuable chemicals. This review presents the current and future state of energy, energy sources, biomass properties and biomass conversion technologies with a focus on hydrothermal technologies.Öğe Use of a Lewis acid, a Bronsted acid, and their binary mixtures for the hydrothermal liquefaction of lignocellulose(Elsevier Sci Ltd, 2021) Alper, Koray; Wang, Yun-Yan; Meng, Xianzhi; Tekin, Kubilay; Karagoz, Selhan; Ragauskas, Arthur J.The main objective of the present study is to investigate the effect of a Lewis acid, Bronsted acid, and their combined use on the hydrothermal liquefaction of lignocellulosic biomass. Hydrothermal liquefaction of teak wood was conducted at 250, 300 and 350 degrees C for 15, 30 and 60 min. Hydrothermal liquefaction of teak wood was carried out at 300 degrees C for 30 min (the best optimum conditions) without and with the use of Mg(ClO4)(2), HClO4, and HClO4/Mg(ClO4)(2) at various loadings (2-10 mmol/15 g wood). The highest bio-oil yield was obtained with the non-catalytic run. All tested catalysts have negative effect on bio-oil yields. The bio-oil yields generally decreased with increasing the catalyst loadings. The deoxygenation degree in bio-oils changed depending on the type of catalyst and loading. A high degree of de-oxygenation took place with Mg(ClO4)(2) catalysts. An increased catalyst loading led to decreased aromatic contents of bio-oils catalysed by either Mg(ClO4)(2) or HClO4. The use of a catalyst increased total naphtha fractions in bio-oils. The highest heating value of the bio-oil was estimated to be approximately 30 MJ/kg. Gas chromatography-mass spectrometry analysis revealed that the bio-oils from the non-catalytic and catalytic runs contained aldehydes, ketones, phenols, acids, esters and alcohols. The relative yields of the oxygenated compounds were affected by catalyst type.Öğe Use of a Lewis acid, a Bronsted acid, and their binary mixtures for the liquefaction of lignocellulose by supercritical ethanol processing(Royal Soc Chemistry, 2021) Alper, Koray; Wang, Yun-Yan; Meng, Xianzhi; Tekin, Kubilay; Karagoz, Selhan; Ragauskas, Arthur J.Supercritical ethanol liquefaction of teak wood was carried out at 300 degrees C for 30 min without and with the use of Mg(ClO4)(2), HClO4, and HClO4/Mg(ClO4)(2) at various loadings (2-10 mmol). The bio-oil yield from the non-catalytic supercritical ethanol liquefaction of teak wood was similar to 41 wt%. The highest bio-oil yield (similar to 58.2 wt%) was obtained with the catalytic run using 2 mmol of Mg(ClO4)(2). In the catalyzed trials, with the use of either Mg(ClO4)(2) or HClO4, an increase in catalyst amounts resulted in a decrease in bio-oil yields. There was no clear trend for the use of co-catalysts. A degree of de-oxygenation was observed with the use of the catalysts studied. The O/C atomic ratio of the bio-oil from the non-catalytic was 0.44. The O/C atomic ratios in the bio-oil produced from catalytic runs ranged from 0.25 to 0.38. In the bio-oil from the non-catalytic run, the major compound was phenolic species, whereas esters were dominant in the bio-oils from the catalytic runs. The type of catalyst and its amount had significant effects on the product distributions and compositions. The prominent ester compounds were ethyl lactate and ethyl levulinate. The highest relative yield of ethyl levulinate was 49.1% and obtained with the use of the Mg(ClO4)(2)/HClO4 (2 mmol : 10 mmol) catalyst. The heating values of the bio-oils from catalytic runs were higher than that of the non-catalytic run. The highest heating value of 31.21 MJ kg(-1) was obtained with the Mg(ClO4)(2)/HClO4 (2 mmol : 10 mmol) catalyst.
