Importance of chain length on physicochemical and crystalline properties of organic homologs

S. H. Yalkowsky, G. L. Flynn, T. G. Slunick

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

It has been observed that certain physical properties of normal alkyl p‐aminobenzoates (i.e., their melting behavior and their solubilities in water, silicone oil, and hexane) exhibit an unusual dependency upon chain length. Each property is characterized by a definite break in the chain length profile about the butyl ester. However, the silicone oil‐water and hexane‐water partition coefficients of these esters show a regular increase with chain length extending over many orders of magnitude. The overall behavior of these homologs is attributed to basic difference in the crystal lattices of short (≤four carbons) and long (⩽four carbons) homologs. X‐ray patterns and thermal data were obtained and are supportive of this conclusion. As an additional verification, the hexane solubility of each compound was calculated by Scatchard‐Hildebrand theory using the thermal data and empirically estimated solubility parameters. Agreement between calculated and experimental values is excellent. Because of relationships drawn for the influence of chain length on solubility and relative solubility (partition coefficients), these experiments also indicate a convenient method of estimating congeneric solubilities in other solvents.

Original languageEnglish (US)
Pages (from-to)852-857
Number of pages6
JournalJournal of pharmaceutical sciences
Volume61
Issue number6
DOIs
StatePublished - Jun 1972
Externally publishedYes

Keywords

  • Alkyl p‐aminobenzoates—effect of chain length on melting point, solubilities, partition coefficients, crystalline properties
  • Chain length effect—melting point, solubilities, partition coefficients, and crystalline properties of alkyl p‐aminobenzoates
  • Homologous alkyl series, p‐aminobenzoates—effect of chain length on melting point, solubilities, partition coefficients, crystalline properties
  • Structure‐activity relationships—effect of alkyl chain length on physicochemical and crystalline properties, p‐aminobenzoate esters

ASJC Scopus subject areas

  • Pharmaceutical Science

Fingerprint

Dive into the research topics of 'Importance of chain length on physicochemical and crystalline properties of organic homologs'. Together they form a unique fingerprint.

Cite this