利用Anton Paar DMA4500振动管密度计测量了293．15K时二元体系甲苯-N，N-二甲基甲酰胺（C6H5CH3-DMF）在C6H5CH3（摩尔分数0～1）中的溶液密度，利用最小二乘法关联了溶液密度与组成的函数关系，关联精度为±0．005kg／m^3。通过...利用Anton Paar DMA4500振动管密度计测量了293．15K时二元体系甲苯-N，N-二甲基甲酰胺（C6H5CH3-DMF）在C6H5CH3（摩尔分数0～1）中的溶液密度，利用最小二乘法关联了溶液密度与组成的函数关系，关联精度为±0．005kg／m^3。通过密度数据分别计算了二元体系中C6H5CH3和DMF的表观摩尔体积，并利用非线性最小二乘拟合法，分别拟合得到了优化的C6H5CH3和DMF的表观摩尔体积和摩尔分数的函数关系，以及C6H5CH3和DMF的表观摩尔体积和质量分数的函数关系．通过对函数关系的极限运算得到了C6H5CH3和DMF的极限偏摩尔体积、标准偏摩尔体积和摩尔体积．还计算了不同组分下体系的超额摩尔体积，数据可用四参数Redlich—Kister方程关联拟合得到方程系数．计算关联了C6H5CH3和DMF的超额偏摩尔体积与摩尔分数的关系．由三参数多项式极限法得到组分的极限超额偏摩尔体积值与Redlich—Kister系数法得到的值在误差范围内一致．展开更多
Density data have been reported for glycine, DL-α-alanine, DL- α-amino-n-butyric acid, DL-valine and DL-leucin in aqueous solutions of 0. 5, 1. 0, 1. 5 and 2. 0 mol. kg - 1 sodium butyrde at 308. 15 K. The apparent ...Density data have been reported for glycine, DL-α-alanine, DL- α-amino-n-butyric acid, DL-valine and DL-leucin in aqueous solutions of 0. 5, 1. 0, 1. 5 and 2. 0 mol. kg - 1 sodium butyrde at 308. 15 K. The apparent molar volums V2. and standard partial molar volumes V2 for the amino acids in aqueous sodium butyrate solutions have been calculated. The linear correlation betwee V2 and the numbe of carbon atoms in the alkyl chain of the amino acids has been observed and utilized to estimate the contribuons of the chargh end groups (NH3+, COO- ), CH2 group and other alkyl chains of the nmino acids to V2. The results show that values for ( COO- ) inerease, while those for CH2 decrease, with sodium butyrate concentration-.The hydration number of the amino acids decreases With increasing electrolyte concentrations. These phenomena are discussed by means of the dehydration effect of electrolyte on the amino acids.展开更多
文摘利用Anton Paar DMA4500振动管密度计测量了293．15K时二元体系甲苯-N，N-二甲基甲酰胺（C6H5CH3-DMF）在C6H5CH3（摩尔分数0～1）中的溶液密度，利用最小二乘法关联了溶液密度与组成的函数关系，关联精度为±0．005kg／m^3。通过密度数据分别计算了二元体系中C6H5CH3和DMF的表观摩尔体积，并利用非线性最小二乘拟合法，分别拟合得到了优化的C6H5CH3和DMF的表观摩尔体积和摩尔分数的函数关系，以及C6H5CH3和DMF的表观摩尔体积和质量分数的函数关系．通过对函数关系的极限运算得到了C6H5CH3和DMF的极限偏摩尔体积、标准偏摩尔体积和摩尔体积．还计算了不同组分下体系的超额摩尔体积，数据可用四参数Redlich—Kister方程关联拟合得到方程系数．计算关联了C6H5CH3和DMF的超额偏摩尔体积与摩尔分数的关系．由三参数多项式极限法得到组分的极限超额偏摩尔体积值与Redlich—Kister系数法得到的值在误差范围内一致．
文摘Density data have been reported for glycine, DL-α-alanine, DL- α-amino-n-butyric acid, DL-valine and DL-leucin in aqueous solutions of 0. 5, 1. 0, 1. 5 and 2. 0 mol. kg - 1 sodium butyrde at 308. 15 K. The apparent molar volums V2. and standard partial molar volumes V2 for the amino acids in aqueous sodium butyrate solutions have been calculated. The linear correlation betwee V2 and the numbe of carbon atoms in the alkyl chain of the amino acids has been observed and utilized to estimate the contribuons of the chargh end groups (NH3+, COO- ), CH2 group and other alkyl chains of the nmino acids to V2. The results show that values for ( COO- ) inerease, while those for CH2 decrease, with sodium butyrate concentration-.The hydration number of the amino acids decreases With increasing electrolyte concentrations. These phenomena are discussed by means of the dehydration effect of electrolyte on the amino acids.
