The Distribution of Bio-Oil Components with the Effects of Sub/Supercritical Ethanol and Free Radicals during Cellulose Liquefaction

BioResources

Xing Wei¹  Xin-An Xie¹  Ya-li Wang¹  Yan Li¹  Cheng-zheng Tang²  Wei Li²  Lu Li²  Di Fan² 

[1] China;College of Food Science, South China Agricultural University, Guangzhou 510640, China;

关键词: Hydroxyl radical;    Cellulose liquefaction;    Hydrogen radical;    Sub/Supercritical ethanol;   

DOI  :  10.15376/biores.11.4.9771-9788

来源: DOAJ

【 摘 要 】

Hydroxyl radicals (HO•) and hydrogen radicals (H•) produced from sub/supercritical ethanol have an obvious contribution on cellulose liquefaction for bio-oil production. Salicylic acid was employed as the HO• trap and CCl4 was employed as the H• trap to investigate the role of HO• and H• on the formation pathways of dominant chemical components in bio-oil during cellulose liquefaction in sub/supercritical ethanol (mostly ketones and esters). The yield of bio-oil decreased from 24.7% to 20.7% with the addition of CCl4, while the bio-oil yield increased from 29.3% to 47.9% with the addition of salicylic acid. Gas chromatography/mass spectrometry results showed that the yields of ketones, esters, and phenols in the bio-oil were 22.3%, 8.8%, and 4.7%, respectively, without salicylic acid or CCl4. The highest yields of esters and phenols increased to 21.6% and 36.9%, respectively, in the presence of salicylic acid. The yield of ketones decreased to 14.1%. Experimental data indicated that the cleavage of C-O-C and C-C bonds in the cornstalk cellulose initially generated many active cellulose fragments. Then, platform chemicals were formed from these fragments through aromatization, isomerization, aldol condensation, Baeyer-Villiger oxidation, and trans-Diels-Alder ring-opening with the redox of HO• and H•.

【 授权许可】

Unknown