Ethanol-Enhanced Liquefaction of Lignin with Formic Acid as an <i>in Situ</i> Hydrogen Donor

Ouyang, Xinping; Huang, Xiangzhen; Zhu, Yuan; Qiu, Xueqing

doi:10.1021/acs.energyfuels.5b01127

Cited by 45 publications

(23 citation statements)

References 21 publications

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“…The valorization of lignin has several applications, such as synthesis of bio‐oil, phenolic resins, adhesives of polyurethane foams, carbon fiber, etc. One of the significant conversion pathways for lignin is liquefaction which generates bio‐oil and phenolic monomers . The development of lignin liquefaction process can considerably help to increase the commercial value of lignin.…”

Section: Introductionmentioning

confidence: 99%

“…One of the significant conversion pathways for lignin is liquefaction which generates bio-oil and phenolic monomers. [9][10][11][12] The development of lignin liquefaction process can considerably help to increase the commercial value of lignin. However, new strategies are required to substitute lignin as raw material alternative to fossil feedstocks because of the high oxygen content, complex structure of lignin, etc.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Solvent, Role of Formic Acid and Rh/C Catalyst for the Efficient Liquefaction of Lignin

et al. 2019

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We demonstrate highly efficient liquefaction of alkali lignin with a very high yield of THF‐soluble bio‐oil (91.5 wt %) using formic acid (FA) and Rh/C catalyst under relatively mild reaction conditions (250 °C, 6 h) in EtOH−H2O co‐solvent system. The monomeric products are identified in which alkyl guaiacols accounts for the main proportion. The role of FA was not only used as a liquid‐phase in‐situ hydrogen source but also acts as organic acid which can catalyze the hydrolysis reaction of −C−O−C ether bonds of lignin. Moreover, in the present study, the role of Rh/C and FA is demonstrated for the liquefaction of lignin. The replacement of pure H2 gas by the liquid‐phase FA (hydrogen source) can effectively prevent the char formation. The utilization of Rh/C catalyst helps for the conversion of alkenyl guaiacols to alkyl guaiacols suggesting the hydrogenation of phenolic monomers and further cleavage by hydrogenation results in the formation of bio‐oil with lower molecular weight (Mn=466 g mol−1) as well as lower O/C ratio (0.26).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Solvent, Role of Formic Acid and Rh/C Catalyst for the Efficient Liquefaction of Lignin

et al. 2019

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“…Hydrogen donor molecules are thought to convert lignin through catalytic transfer hydrogenation mechanisms or act as an in situ hydrogen source for lignin hydroprocessing [93][94] . In some cases a solvent is used to improve the heat and mass transfer rates and enhance the miscibility of the reaction mixture 93,[95][96] . Low molecular weight alcohols, such as ethanol, methanol and isopropanol, ionic liquids and water are among the preferred choices 8 .…”

Section: Reductive Methodsmentioning

confidence: 99%

“…This hydrogen donor molecule decomposes mainly into molecular hydrogen and CO 2 under the LtL conditions creating a reductive environment (low amounts of CO and H 2 O are also produced). Most of the researchers believe that formic acid act either as an in-situ hydrogen source or a hydrogen donor molecule through catalytic-hydrogen transfer reactions 93,96,[138][139][140] . However, its role in the lignin conversion process is not fully understood and there are no published mechanisms that can explain why formic acid is more active than other hydrogen donors.…”

Section: Lignin-to-liquid Concept (Ltl)mentioning

confidence: 99%

Simultaneous catalytic de-polymerization and hydrodeoxygenation of lignin in water/formic acid media with Rh/Al2O3, Ru/Al2O3 and Pd/Al2O3 as bifunctional catalysts

Bengoechea

Hertzberg

Miletić

et al. 2015

Journal of Analytical and Applied Pyrolysis

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Among all biomass sources, the lignocellulosic biomass derived from agricultural and forestry wastes is considered as the most adequate substitute for fossil sources due to its abundance, versatility and lack of competition with food resources. Yet, the efficient and economically feasible conversion of lignin into fuels and chemicals remains one of the major technology gaps for the development of lignocellulosic biorefineries. Here, the chemical nature of the lignin biopolymers will be described based on their botanical origin and the isolation process. After summarizing the most relevant advances in the catalytic conversion of lignin, the recently developed Ligninto-Liquids (LtL) process will be described and its major challenges addressed. 1.1 Energy transition: from crude oil to a biomass based energy system According to the results of the 2015 Revision 1 published by the Department of Economic and Social Affairs of United Nations (UN-DESA), the world population reached 7.3 billion as of mid-2015. The global population is expected to rise in the short-to-medium term, reaching between 8.4 and 8.6 billion in 2030 and between 9.5 and 13.3 billion by the end of the century 1. Hence, the demand of natural resources for the production of food, energy and chemicals is expected to increase significantly in the course of the century. It is important, therefore, to develop an integrated production model that addresses the sustainable and environmentally friendly production and distribution of these three basic commodities: food, energy and raw materials (chemicals). The challenge is of immense magnitude. In terms of food supply, the Food and Agriculture Organization (FAO) expects an steady growth of the total agricultural product consumption of 1.1 % per year until 2050 2. The global energy demand is estimated to grow even faster, by 48 % between 2012 and 2040 (Figure 1.1, above); fossil fuels being the major contributor providing over 78 % of the demand 3. The same trend is observed for the bulk chemicals, of which organic chemicals account for 4 CHAPTER 1

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“…The synergistic effect of water/ethanol mixture in the liquefaction of rice husk for bio-oil production via the HTL process was also observed by Liu et al (2013). Besides the high bio-oil yield, the addition of ethanol to water also affects the distribution of phenolics such as phenol, ethylphenol and guaiacols, ethylguaiacol and syringol in the bio-oil as well (Ye et al 2012, Ouyang et al 2015). Recently, Kosinkova et al (2015) reported that aqueous ethanol improved the higher heating value (HHV) of bio-oil to be used in the field of biodiesel applications.…”

Section: Introductionmentioning

confidence: 84%

The effect of ethanol on hydroxyl and carbonyl groups in biopolyol produced by hydrothermal liquefaction of loblolly pine: 31P-NMR and 19F-NMR analysis

Celikbag

Via

Adhikari

et al. 2016

Bioresource Technology

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The goal of this study was to investigate the role of ethanol and temperature on the hydroxyl and carbonyl groups in biopolyol produced from hydrothermal liquefaction of loblolly pine (Pinus spp.) carried out at 250, 300, 350 and 390°C for 30min. Water and water/ethanol mixture (1/1, wt/wt) were used as liquefying solvent in the HTL experiments. HTL in water and water/ethanol is donated as W-HTL and W/E-HTL, respectively. It was found that 300°C and water/ethanol solvent was the optimum liquefaction temperature and solvent, yielding up to 68.1wt.% bio-oil and 2.4wt.% solid residue. (31)P-NMR analysis showed that biopolyol produced by W-HTL was rich in phenolic OH while W/E-HTL produced more aliphatic OH rich biopolyols. Moreover, biopolyols with higher hydroxyl concentration were produced by W/E-HTL. Carbonyl groups were analyzed by (19)F-NMR, which showed that ethanol reduced the concentration of carbonyl groups.

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Ethanol-Enhanced Liquefaction of Lignin with Formic Acid as an in Situ Hydrogen Donor

Cited by 45 publications

References 21 publications

Effect of Solvent, Role of Formic Acid and Rh/C Catalyst for the Efficient Liquefaction of Lignin

Effect of Solvent, Role of Formic Acid and Rh/C Catalyst for the Efficient Liquefaction of Lignin

Simultaneous catalytic de-polymerization and hydrodeoxygenation of lignin in water/formic acid media with Rh/Al2O3, Ru/Al2O3 and Pd/Al2O3 as bifunctional catalysts

The effect of ethanol on hydroxyl and carbonyl groups in biopolyol produced by hydrothermal liquefaction of loblolly pine: 31P-NMR and 19F-NMR analysis

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