APPARENT MOLAR HEAT-CAPACITIES AND VOLUMES, VAN-DER-WAALS VOLUMES ANDACCESSIBLE SURFACE-AREAS OF ALKYLATED DERIVATIVES OF CYTOSINE AND URACIL IN AQUEOUS-SOLUTIONS AT 25-DEGREES-C

Densities and specific heat capacities of aqueous solutions: 1,3,5,6-t etramethyluracil, 1,6-dimethyl-3-ethyluracil, 1,6-dimethyl-3-propylura cil, 1,6-dimethyl-3-butyluracil, 1,N4-trimethylcytosine, 1,N4-dimethyl -5-ethylcytosine, 1,N4-dimethyl-5-propylcytosine, 1,N4-dimethyl-5-buty lcytosine were determined using flow calorimetry and flow densimetry a t 25-degrees-C. Apparent molar volumes and heat capacities, van der Wa als volumes and accessible surface areas were determined. It was state d that for alkylcytosines and alkyluracils partial molar volumes and h eat capacities correlate linearly with the number of substituted methy lene groups -CH2-as well as with the van der Waals volumes and accessi ble surface areas of the compounds studied; for cyclooligouracils the cyclization effect was discussed.