Controlling hydrothermal reaction pathways to improve acetic acid production from carbohydrate biomass.
A two-step hydrothermal process to improve the production of acetic acid was discussed. The first step was to accelerate the formation of 5-hydroxymethyl-2-furaldehyde (HMF), 2-furaldehyde (2-FA), and lactic acid (LA), and the second step was to further convert the furans (HMF, 2-FA) and LA produced in the first step to acetic acid by oxidation with newly supplied oxygen. The acetic acid obtained by the two-step process had not only a high yield but also better purity. The contribution of two pathways via furans and LA in the two-step process to convert carbohydrates into acetic acid was roughly estimated as 85-90%, and the ratio of the contributions of furans and LA to yield acetic acid was estimated as 2:1. The fact that WO of carbohydrates is not capable of producing a large amount of acetic acid, while the two-step process can enhance the acetic acid yield, can be explained because formic acid is a basic product of direct oxidation of carbohydrate, and acetic acid in WO of carbohydrates may come from the oxidation of dehydration products of aldose.
Jin
Fangming
F
Department of Environmental Science and Technology, Graduate School of Environmental Studies, Tohoku University, Aoba-ku, Sendai 980-8579, Japan. jin@mail.kankyo.tohoku.ac.jp
Zhou
Zhouyu
Z
Moriya
Takehiko
T
Kishida
Hisanori
H
Higashijima
Hisao
H
Enomoto
Heiji
H
D019342:Acetic Acid / Q000032:analysis*; D018533:Biomass; D019149:Bioreactors; D050260:Carbohydrate Metabolism; D005663:Furans / Q000378:metabolism; D007202:Indicators and Reagents / Q000032:analysis*; D019344:Lactic Acid / Q000378:metabolism; D010084:Oxidation-Reduction
D005663:Furans; D007202:Indicators and Reagents; D019344:Lactic Acid; D019342:Acetic Acid