Effects of hydroxyl and hydrogen free radicals on the liquefaction of cellulose in sub/supercritical ethanol

Li, Wei; Xie, Xianmei; Tang, Cheng-zheng; Li, Yan; Li, Lü; Wang, Yali; Wang, Xing; Fan, Di

doi:10.1016/s1872-5813(16)30021-4

Cited by 10 publications

(6 citation statements)

References 9 publications

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“…CCl 4 is known to trap the H˙ radicals inside the cavitation bubbles. 16 Despite the poor miscibility of CCl 4 in water, addition of CCl 4 completely inhibited the reaction, highlighting the important role of H˙ radicals in the depolymerisation of cellulose ( Table 1 , entry 3). This result is also consistent with our experiments under air, O 2 and Ar/O 2 for which the lowest yields in glucose were observed ( Scheme 4 ).…”

Section: Resultsmentioning

confidence: 99%

“…Inspired by our previous works on NTAP, 13 we conceived that these in situ produced radicals should theoretically induce the cleavage of the glycosidic bonds of cellulose. 16 Being able to selectively depolymerize cellulose with H˙ and ˙OH radicals without side degradation of released glucose into the bulk solution is a challenging scientific task, which is addressed in this study.…”

Section: Introductionmentioning

confidence: 99%

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Selective radical depolymerization of cellulose to glucose induced by high frequency ultrasound

et al. 2020

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Selective radical depolymerization of cellulose to glucose induced by high frequency ultrasound

et al. 2020

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“…According to 3.5.1 and 3.5.2(above), the formation pathways and networks of dominant chemicals (ketones, esters, acids, alcohols, alkanes, aldehydes, glucosides, etc.) during cellulose liquefaction in supercritical acetone were developed (21,29,34,37,38). It is shown in Figure 8.…”

Section: Chemicals Distribution In Bo and The Formation Pathwaysmentioning

confidence: 99%

“…For example, both the liquid product yield and cellulose conversion rate were higher when cellulose was liquefied in supercritical ethanol (14)(15)(16), and the supercritical water also had a contribution on the cellulose depolymerization and conversion (17)(18)(19). The reason was presumed that supercritical solvents can produce hydroxyl radicals, hydrogen radicals and alkyl radicals, then the C-O-C, C-C, C-H and -OH bonds were cleave under the attack of radicals which had a contribution on cellulose converting to liquid products (8,20,21). Additionally, it was found that ketones, esters, alkanes and aromatics were in high content in the liquid product of cellulose liquefaction in supercritical solvents (22)(23)(24)(25), these green platform chemicals were widely used as important chemical materials.…”

Section: Introductionmentioning

confidence: 99%

Investigation of cornstalk cellulose liquefaction in supercritical acetone by FT-TR and GC-MS methods

Xie

Sun

et al. 2019

Green Chemistry Letters and Reviews

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Cornstalk cellulose was liquefied in supercritical acetone at various temperature by a high-pressure autoclave, where the maximum yield of bio-oil was 43.79% and the highest conversion rate of cellulose was 72.13%. FT-TR spectrums showed that the CO -C and CC bonds in cellulose were cleaved under the attack of supercritical acetone, then active fragments were produced and transformed into liquefaction products. GC-MS results showed that the dominant components in bio-oil were ketones, esters, alkanes, etc. As the acetone dosage increased, ketones and glucosides increased while esters and alkanes decreased. A higher temperature was suitable for ketones and esters formation, which had an inhibition on alkanes formation. Finally, the formation of pathways and networks of dominant chemicals during cellulose liquefaction in supercritical acetone were developed. This investigation contributes to the knowledge of cellulose liquefaction in supercritical solvents for bio-oil and platform chemicals, which can provide an alternative method for biomass resources utility.

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“…Supercritical ethanol acts as an effective reactant medium by reducing the viscosity of biocrude oil. Ethanol can also produce hydroxyl and hydrogen radicals in reactions with biocrude oil in the supercritical state [14,15]. Among lignocellulosic biomass, coffee has a huge potential for biomass feedstock, simply because it is one of the most popular beverages worldwide.…”

Section: Introductionmentioning

confidence: 99%

Upgrading of Coffee Biocrude Oil Produced by Pyrolysis of Spent Coffee Grounds: Behavior of Fatty Acids in Supercritical Ethanol Reaction and Catalytic Cracking

2021

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Spent coffee grounds contain lipids (fatty acids) in addition to cellulose, hemicellulose, and lignin. The reaction process for upgrading biocrude oil produced from spent coffee grounds is different from that followed for upgrading biomass pyrolysis oil, such as processes that utilize sawdust. The feasibility of upgrading coffee biocrude oil through a supercritical ethanol reaction with plastic pyrolysis oil and through catalytic cracking for the improvement of the undesirable properties of biocrude oil, caused by the presence of oxygenated compounds, was evaluated. The initial oxygen content of the coffee biocrude oil was 16.9 wt%. The oil comprised a total content of 40.9% fatty acids, as found by analyzing the GC-MS peak area. After the supercritical ethanol reaction at 340 ∘C, the oxygen content was decreased to 9.9 wt%. When the MgNiMo/AC catalyst was applied to the supercritical reaction, the oxygen content was further decreased to 8.5 wt%. The esterification of the fatty acids in the biocrude oil with ethanol converted them to esters. After the supercritical reaction of coffee biocrude oil with plastic pyrolysis oil (1:2 (w/w)), the oxygen content was 6.4 wt%. After the catalytic cracking of the biocrude oil by Ni/MCM-41 at 400 ∘C, the fatty acids were converted to hydrocarbons, C9 to C21, and the oxygen content decreased to a final value of 2.8 wt%.

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Effects of hydroxyl and hydrogen free radicals on the liquefaction of cellulose in sub/supercritical ethanol

Cited by 10 publications

References 9 publications

Selective radical depolymerization of cellulose to glucose induced by high frequency ultrasound

Selective radical depolymerization of cellulose to glucose induced by high frequency ultrasound

Investigation of cornstalk cellulose liquefaction in supercritical acetone by FT-TR and GC-MS methods

Upgrading of Coffee Biocrude Oil Produced by Pyrolysis of Spent Coffee Grounds: Behavior of Fatty Acids in Supercritical Ethanol Reaction and Catalytic Cracking

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