生化模型化合物的热化学研究 I.L(+)-天氡氨酸和L(+)-谷氨酸在水中的低浓度溶解焓

It has been found that an ordinary reaction calorimeter can be used for the determination of small heat effects (10^-^3 to 10^-^4 C temperature change) by correctly evaluating the Newton's cooling constant K through a reference temperature technique. This technique was applied to the determination of the integral enthalpies of solution of L(+)-aspartic acid and L(+)-glutamic acid in water in the concentration range of 10^-^3 to 10^-^4 mol/kg which were found equal to 25.8+/-0.6 and 25.7+/-0.4kJ/mol respectively (twice standard deviation). No CH2 increment effect has been revealed in the solution enthalpies of these two amino-acids.     

生化模型化合物的热化学研究 Ⅰ. L( )-天冬氨酸和L( )-谷氨酸在水中的低浓度溶解焓

本文报道利用参考温升测定牛顿冷却常数K值,适于在常量环境恒温潜水式反应量热计中测定温升只有10~(-3)～10~(-4)℃的较小热量。在浓度为10~(-3)～10~(-4)mol/kg时测定了L( )一天冬氨酸和L( )-谷氨酸在水中的积分溶解焓。在实验偏差范围内,没有观察到溶解焓对浓度的依赖关系。ΔH_s(298.15K)分别为25.8±0.6和25.7±0.4kJ/mol.偏差为平均值标准偏差的两倍。这两种氨基酸分子中由于差一个亚甲基而引起的水中摩尔积分溶解焓差并不明显。     

溶解量热法测定无水四氟化铀标准生成焓

本文通过测定样品在三氯化铝-盐酸溶液中的溶解-混合焓,引用了文献上有关的焓值,得到了无水四氟化铀(晶)标准生成焓.结果是:△H₁~0(298.15K)=-1894.5±7.5千焦耳·克分子^-1.文中对Мальцев等的反应方案作了修改、实测和讨论,结果与本文一致.