绿色溶剂γ-戊内酯中果糖催化转化为5-羟甲基糠醛

通过生物质衍生糖的酸催化转化制备生物质基平台化合物5-羟甲基糠醛受到关注。常用又有效的溶剂包括离子液体和二甲基亚砜等,但这些溶剂黏度高,易造成空气污染。以γ-戊内酯作为溶剂,研究果糖催化转化为5-羟甲基糠醛的绿色过程,系统研究酸催化剂种类、反应温度、催化剂用量、果糖初始浓度及底物种类等对5-羟甲基糠醛产率的影响。通过反应条件的优化,以HCl溶液为催化剂,在果糖初始质量浓度2%、反应温度100℃和反应时间30 min条件下,5-羟甲基糠醛产率为93.5%。5-羟甲基糠醛产率随果糖初始添加量的增加而呈下降趋势,但果糖初始质量浓度为10%时,5-羟甲基糠醛产率仍保持约90%,表明γ-戊内酯是一种将果糖催化转化为5-羟甲基糠醛的优良绿色溶剂。

Measurement and correlation of supercritical CO_(2) and ionic liquid systems for design of advanced unit operations

Ionic liquids combined with supercriticalfluid technology hold great promise as working solvents for developing compact processes.Ionic liquids,which are organic molten salts,typically have extremely low volatility and high functionality,but possess high viscos-ities,surface tensions and low diffusion coefficients,which can limit their applicability.CO_(2),on the other hand,especially in its supercritical state,is a green solvent that can be used advantageously when combined with the ionic liquid to provide viscosity and surface tension reduction and to promote mass transfer.The solubility of CO_(2) in the ionic liquid is key to estimating the important physical properties that include partition coefficients,viscosities,densities,interfacial tensions,thermal conductivities and heat capacities needed in contactor design.In this work,we examine a subset of available high pressure pure component ionic liquid PVT data and high pressure CO_(2)-ionic liquid solubility data and report new correlations for CO_(2)-ionic liquid systems with equations of state that have some industrial applications including:(1)general,(2)fuel desulfurization,(3)CO_(2) capture,and(4)chiral separation.New measurements of solubility data for the CO_(2) and 1-butyl-3-methylimidazolium octyl sulfate,[bmim][OcSO4]system are reported and correlated.In the correlation of the CO_(2) ionic liquid phase behavior,the Peng-Robinson and the Sanchez-Lacombe equations of state were considered and are compared.It is shown that excellent correlation of CO_(2) solubility can be obtained with either equation and they share some common characteristics regarding inter-action parameters.In the Sanchez-Lacombe equation,parameters that are derived from the supercritical region were found to be important for obtaining good correlation of the CO_(2)-ionic liquid solubility data.

Catalytic hydrotreatment of alkaline lignin and its consequent influences on fast pyrolysis

The current state of lignin has been characterized by these three:(1)as one of the main components in lignocellulosic biomass with an abundant amount;(2)not be taken seriously but treated as a waste product;(3)underutilized due to a complex and stubborn structure.However,lignin can be a rich source for hydrocarbons and aromatic compounds when gives appropriate utilization.In this work,we have studied the hydrotreatment of alkaline lignin(AL)under relatively mild conditions and further investigated the characterization of hydrogenated lignin(HL),especially the behavior during fast pyrolysis.The recovery of the HL decreased with increasing reaction temperature from 60 wt.%to 41 wt.%in the range of 150-250℃.The hydrotreated products were analyzed using Elemental Analysis,FTIR(for HL)and GC-MS(for bio-oil).The HL samples were found to have a higher hydrogen/carbon atomic effective ratio(H/C_(eff) ratio)and a higher degree of saturation than AL.Compared to the internal structure of the lignin before and after hydrotreatment,the side chain groups were removed from AL during the process.After that,from the fast pyrolysis of HL,it was observed that more light hydrocarbons and aromatic compounds were formed than that of AL.Furthermore,fast pyrolysis in the hydrogen atmosphere revealed that more volatile fractions were released compared to the Helium atmosphere.The total olefins yield was increased for HL compared AL from 1.02 wt.%to 3.1 wt.%at 250℃for 7 hours.This study of HL is instructive to some extent for the industrial utilization of lignin.