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21.
22.
The state of water in water-swollen poly(vinyl alcohol-co-itaconic acid) membranes, having various water contents from 0.31 to 0.83, was investigated by d.s.c. measurements and compared with those in water-swollen poly(vinyl alcohol) membranes. The amount of freezing water in the membranes was estimated by use of a relationship between the phase transition temperature and the enthalpy of the crystallization of supercooled water. The melting temperature of the water in the membranes immersed in urea and NaCl 0–2 mol l?1 aqueous solutions was also determined by d.s.c. analysis. The present study proposes a method for estimating the solubilities of urea and NaCl in both of the freezing and the non-freezing water using the melting point depression of the freezing water in the membranes immersed in the solute solution. 相似文献
23.
This work is an experimental and theoretical study of antimony speciation and the solubility of Sb2O5, Sb2O3 and Sb2(SO4)3 at 298 K in aqueous sulphuric acid solutions (0 to 6 kmol/m3). A thermodynamic model was developed to quantify the solubility products and aqueous metal speciation. Main dissolved species were H3SbO3(aq) and H3SbO4(aq). The solubility of antimony increases with increasing solution acidity and with the presence of hydrogen peroxide in the solution. The following standard equilibrium constants at 298 K were obtained: Log K0(Sb2O5) = 11.7±0.5, Log K0(Sb2O3) = 32±1, and Log K0(Sb2(SO4)3) = 55±2. 相似文献
24.
The effects of different inorganic and organic counterions on the physicochemical behavior of three commercial linear alkylbenzene
sulfonates (LAS) have been studied. It has been found that the counterion hydration radius of the corresponding commercial
linear alkylbenzene sulfonates has great influence on solubility, viscosity, surface tension and critical micelle concentration
(CMC). The counterion has no influence on the detergency performance of the finished formulation. The alkyl chain length and
the presence of tetralines have an important influence on solubility, viscosity and surface tension. 相似文献
25.
26.
用浊点法测定了四氟硼酸1-丁基-3-甲基咪唑—水—碳酸钠体系在常压30℃下的溶解度曲线及密度曲线,并用经验方程进行了关联。用浊点—密度法测定了该体系的液液相平衡数据,绘制了相应的相图。结果表明:双水相体系一相以离子液体和水为主,碳酸钠的含量很少,另一相以碳酸钠和水为主,离子液体的含量很少。该体系既可作为萃取分离体系,也可作为从水溶液中分离回收离子液体的初步体系。用Othmer-Tobias+Bancroft经验方程对相平衡数据进行关联,最大相对误差为94.99%, 最大平均相对误差为15.69%,关联结果不理想。提出用Othmer-Tobias经验方程+溶解度方程对其进行关联,最大相对误差为4.52%,最大平均相对误差为2.77%,关联精度较高,该方法可适用于有一组分含量较低的体系的液液相平衡的关联计算。 相似文献
27.
Peter?S.?Piispanen Marcus?Persson Per?Claesson Torbj?rn?NorinEmail author 《Journal of surfactants and detergents》2004,7(2):147-159
Several novel and some previously known, mostly sugar-based, surfactants have been synthesized and some of their surface properties
have been characterized and compared with those of commercial nonylphenol ethoxylates. The surfactant solubility in water,
ethanol, and dodecane was studied. The properties of these compounds as emulsification agents in systems composed of the surfactant
with water/isopropyl myristate, water/rapeseed oil, and water/dodecane are presented. The aqueous solubility of the surfactants
follows the general trend expected from their hydrophilic-lipophilic balance according to Griffin (HLBG), but it is also clear
that the nature of the headgroup and the structure of the nonpolar part affect the solubility in a manner not aptured in the
standard HLBG concept. An ester or amine group as the connecting unit between the hydrophile and the hydrophobe produces a
more water-soluble surfactant than the corresponding amide derivative. Some effective emulsifiers were found. For instance,
the surfactants with a dehydroabietic nonpolar group appear to be promosing emulsifiers. Most sugar-based surfactants were
able to form macroemulsions of up to around 2 wt/vol% of oil. The stability of many of these amulsions was very high, extending
for months. 相似文献
28.
综述了微孔塑料成型过程中聚合物/气体均相体系形成的影响因素。表征均相体系的重要参数是气体在聚合物中的溶解度,因此通过SEM、玻璃化转变温度法、粘度法等间接方法来衡量溶解度,可以间接表征均相体系。对影响均相体系形成的压力、温度、时间和剪切作用等工艺条件进行了分析。适当增加压力、升高温度有利于均相体系的形成.剪切作用可提高气体的扩散性和溶解性,同时还可大大缩短均相体系形成所需要的时间。 相似文献
29.
A supercritical fluid extraction method has been applied to test the feasibility of tocopherol concentration from soybean
sludge with carbon dioxide at temperatures and pressures ranging from 35 to 70°C and 200 to 400 bar, respectively. The supercritical
solubility of the esterified soybean sludge was over 4–6 times greater than that of the original soybean sludge. By a simple
batch-type one-stage method the tocopherols in the esterified soybean sludge could be concentrated up to 40 wt%. The overall
results of the present study show that soybean sludge initially containing about 13–14 wt% tocopherols may require a countercurrent
multistage column to be highly and effectively concentrated. 相似文献
30.