A series of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) analogue surfactants [sodium dibutyl sulfosuccinate (DBSS), sodium dipentyl sulfosuccinate (DPSS), sodium dihexyl sulfosuccinate (DHSS), and sodium dioctyl sulfosuccinate (DOSS)] were synthesized and characterized with 1H NMR and elemental analysis. The solubilities of surfactants in supercritical CO2 (scCO2) and supercritical 1,1,1,2-tetrafluoroethane (HFC-134a) fluids at a temperature range from (308 to 338) K and under pressures of (10 to 30) MPa were measured using a static method coupled with gravimetric analysis. The solubilities of these surfactants are much higher in HFC-134a fluid as compared with that in scCO2. The solubilities increased with increasing temperature and pressure for both scCO2 and HFC-134a fluids. The solubilities in scCO2 increased with increasing carbon atom number of surfactant, whereas they decreased with increasing carbon atom number of surfactant in HFC-134a. The density of scCO2 was simulated with the Peng-Robinson (P-R) equation. The experimental data were used to validate the accuracy of the P-R equation.

A series of Aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulfosuccinate) analogue fluorinated surfactants, i.e.,the sodium salt of bis(2,2,3,3,3-pentafluoropropyl) 2-sulfosuccinate (di-CF2), the sodium salt of bis(2,2,3,4,4,4-hexafluorobutyl)2-sulfosuccinate (di-HCF3), the sodium salt of bis(3,3,4,4,5,5,6,6,6-nonafluorohexyl)2-sulfosuccinate (di-HCF4), and the sodium salt of bis(2,2,3,3-tetrafluoropropyl) 2-sulfosuccinate (di-HCF2), were synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, melting point, and elemental analysis. The pressure-temperature (P-T) phase diagrams for water-in-CO2 (W/CO2) and water-in-1,1,1,2-tetrafluoroethane (W/HFC-134a) microemulsions stabilized by the surfactants were determined. In this work, the phase behaviors for different surfactants are obtained in supercritical CO2 (scCO2) and 1,1,1,2-tetrafluoroethane (HFC-134a) as a function of temperature, pressure, and water-to-surfactant ratio. At a fixed temperature, the cloud-point pressures increased with the increase of water-to-surfactant ratio (Wo) and the concentration of the surfactants. The cloud-point pressures for the surfactants in HFC-134a decrease with an increase in temperature at a fixed Wo and a surfactant concentration, which is in opposition to the results obtained in scCO2.

用Benson 基团贡献法计算了碳酸二甲酯(DMC) 的标准摩尔生成焓Δf H0m 、标准摩尔生成吉布斯自由能Δf Gθm 和等压摩尔热容Cp ,m 。计算了不同温度和压力条件下二甲醚(DME) 氧化羰化合成DMC 及DME 与CO2 反应合成DMC 的焓变ΔrHm 、吉布斯自由能变ΔrGm 和平衡常数ln Kθ。计算结果表明:在300～1000 K 的温度及011～30MPa 的压力条件下,由DME 氧化羰化合成DMC 是热力学上可自发进行的反应,而由DME 和CO2 合成DMC 是非自发进行的,需要通过耦合等方式来改变反应途径(或重构反应体系) ,该反应才有可能进行。为由DME 合成DMC 的反应途径设计和催化剂的探索研究提供了热力学依据。

对亚麻快速生物脱胶和温水沤麻过程中的果胶酶、木聚糖酶、纤维素酶、微生物、pH 值和还原糖等进行了动态变化研究。结果表明,2 种脱胶过程中果胶酶和木聚糖酶的变化趋势基本相似,酶活性脱胶前期均增加缓慢,中后期迅速增加;纤维素酶活性的变化趋势有明显的区别,快速生物脱胶的纤维素酶酶活性增加幅度小,酶活性低(0105 IUPmL左右) ,温水沤麻的纤维素酶在发酵72 h后迅速增加,脱胶完成后酶活性达0. 337 9 IUPmL ;微生物的变化趋势基本相似,在脱胶前期迅速增加、脱胶完成时开始下降;pH值和还原糖量的变化趋势分别呈“U”型和“M”型。

在35～55 ℃、7～15 MPa条件下,利用果胶粗酶液和木聚糖酶液,对苎麻韧皮进行超临界CO2 处理及其脱胶试验,考察了超临界CO2 处理苎麻韧皮前后酶液中的活菌数、酶活和脱胶效果。实验结果表明,经超临界CO2 处理1 h左右,苎麻脱胶菌的致死率在99 %以上;不同类型非纤维素降解酶,在超临界条件下的稳定性不同,木聚糖酶比较稳定,酶活仅降低1.6 % ,而果胶粗酶液的稳定性较差,酶活降低23.79 %；超临界CO2 介质有利于加速苎麻酶的脱胶催化反应进程,使苎麻脱胶效果提高60 %～100 %。