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2830311 
Journal Article 
PARTIAL MOLAL VOLUMES OF NORMAL-ALKYL PARAAMINOBENZOATES IN NONPOLAR-SOLVENTS 
Neau, SH; Howard, DR 
1991 
Yes 
International Journal of Pharmaceutics
ISSN: 0378-5173
EISSN: 1873-3476 
77 
2-3 
239-246 
English 
WOS:A1991GT92700017 
The partial molal volumes of ethyl and n-butyl p-aminobenzoate were determined in seven solvents, including benzene, toluene, carbon tetrachloride, cyclohexane, n-dodecane, n-heptane and n-hexane. These p-aminobenzoates were found to have statistically larger partial molal volumes in the long-chain and cyclic alkanes than in the remaining five solvents. The higher partial molal volumes would contribute to deviations from ideal entropies of mixing in the form of excess volumes of mixing. Estimates of the solubility parameters for ethyl and n-butyl p-aminobenzoate were revised using the experimental partial molar volumes and solubility data for these two solutes in each of the seven solvents. The revised solubility parameters indicate that the experimental volumes do not reduce the previously reported variation in the solubility parameter when estimated from solubilities in these seven solvents. Consideration of the entropy of mixing in light of the experimental volumes showed no advantage over the assumption of an ideal entropy of mixing. 
REGULAR SOLUTION THEORY; SOLUBILITY; PARA-AMINOBENZOATE; PARTIAL MOLAL VOLUME; ENTROPY OF MIXING; EXCESS VOLUME OF MIXING