Degradation kinetics of dihydroxyacetone and glyceraldehyde in subcritical and supercritical water

被引:97
作者
Kabyemela, BM
Adschiri, T
Malaluan, R
Arai, K
机构
[1] Department of Chemical Engineering, Tohoku University, Aoba-ku, Sendai 980-77, Aza, Aoba, Aramaki
关键词
D O I
10.1021/ie960747r
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
The degradation kinetics of dihydroxyacetone and glyceraldehyde were studied at temperature ranges of 573-673 K, pressures of 25-40 MPa, and residence times from 0.06 to 1.7 s. The reactions of glyceraldehyde gave both dihydroxyacetone and pyruvaldehyde, and yields of dihydroxyacetone were always higher than those of pyruvaldehyde. The reactions of dihydroxyacetone gave glyceraldehyde and pyruvaldehyde, while the yields of pyruvaldehyde were always higher than those of dihydroxyacetone. This pathway involves the reversible isomerization between glyceraldehyde and dihydroxyacetone and their subsequent dehydration to pyruvaldehyde. A model was formulated on the basis of this pathway, and the kinetic rate constants involved were calculated using the experimental results. As the conditions change from subcritical to supercritical, the Arrhenius relationship becomes discontinuous near the critical point of water. At a constant temperature of 673 K, the kinetics constants showed a general increase with an increase in pressure.
引用
收藏
页码:2025 / 2030
页数:6
相关论文
共 11 条