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Binary freezing‐point diagrams for alpha‐ and beta‐eleostearic acids with each other and with acetamide
Author(s) -
Mod Robert R.,
Skau Evald L.,
Planck Ralph W.
Publication year - 1953
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02633772
Subject(s) - degree of unsaturation , acetamide , chemistry , freezing point , beta (programming language) , alpha (finance) , thermodynamics , organic chemistry , physics , mathematics , construct validity , statistics , computer science , programming language , psychometrics
Summary Complete binary freezing‐point data have been obtained for each of the polymorphic modifications of acetamide with alpha‐eleostearic acid and beta‐eleostearic acid and for alpha‐eleostearic acid with beta‐eleostearic acid. In the light of previously published data the fact that all of these systems are of the simple eutectic type suggests that the tendency of the long‐chain fatty acids to form 1∶1 molecular compounds with acetamide and with each other decreases as the degree of unsaturation increases. The fact that the heat of fusion of beta‐eleostearic acid, 13.2 kcal. per mole, calculated from the freezing‐point data is greater than that for the alpha acid, 10.5 kcal. per mole, corroborates the conclusion that the beta acid is the trans‐trans‐trans modification. Calculations of heats of fusion have been made, based upon all the available freezing‐point data in the literature for binary systems between pairs of C 18 fatty acids of different degrees of unsaturation, and certain trends have been dsicussed.