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测量了顺丁烯二酸二乙酯与正庚烷、正辛烷、正壬烷和正癸烷二元溶液在临界区域不同波长及温度下的浊度.与关联长度、渗透压缩系数、共存曲线相关的三个指前因子(X_o,ξ_o,B)的比例关系为:R=ξ_o[B~2/(4k_BT_cX_o)]~(1/3)(K_B和T_c分别为玻尔兹曼常数与临界温度),R的理论值为0.65～0.67.临界指数γ,ν和β服从指数和规则:3ν=2β+γ.用上述两个关系式及Ornstein-Zernike方程拟合浊度-温度-波长数据,得到γ与ν,在误差范围内与理论值一致.将γ与ν固定在理论值1.241和0.63,得到ξ_o和X_o,结果表明ξ_o和X_o可分别由ξ_oφ_c~(0.85)∝M~n和X_oφ_c~(-1.20)∝M~g表示(φ_c是顺丁烯二酸二乙酯的临界体积分数,M是正构烷烃的摩尔质量),其中n=0.22±.03,g=-0.07±0.09和我们最近提出的理论值0.18和-0.06吻合.
The turbidity of diethyl maleate with n-heptane, n-octane, n-nonane and n-decane in different wavelengths and temperatures in the critical region was measured. The correlations with correlation length, osmotic compression coefficient, coexistence curve The relationship between the three pre-exponential factors (X_o, ξ_o, B) is: R = ξ_o [B ~ 2 / (4k_BT_cX_o)] ~ (1/3) (K_B and T_c are Boltzmann’s constant and critical Temperature), the theoretical value of R is 0.65 ~ 0.67. The critical exponents γ, ν and β are subject to the exponents and rules: 3ν = 2β + γ. The turbidity-temperature-wavelength data are fitted using the above two relations and the Ornstein-Zernike equation , Γ and ν are obtained, which are in agreement with the theoretical value within the error range. The γ and ν are fixed at the theoretical values of 1.241 and 0.63 to obtain ξ_o and X_o. The results show that ξ_o and X_o are respectively determined by ξ_oφ_c ~ (0.85) αM ~ n and X_oφ_c ~ (-1.20) αM ~ g (φ_c is the critical volume fraction of maleic acid diethyl ester, M is the molar mass of n-alkanes), where n = 0.22 ± .03, g = -0.07 ± 0.09 And our recent theoretical values of 0.18 and -0.06 coincide.