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Full-Text Articles in Physical Sciences and Mathematics
The Effects Of Structural Changes On The Formation Of Urea Adducts Of Esters, Gerard Vinton Smith
The Effects Of Structural Changes On The Formation Of Urea Adducts Of Esters, Gerard Vinton Smith
University of the Pacific Theses and Dissertations
An unexpected discovery in 1940 revealed that urea has the peculiar property to form crystalline adducts with many straight chain organic compounds. Since the discovery, considerable time and money have been spent on the elucidation of this phenomenon, and the field of urea adducts has now advanced to the stage at which many empirical rules have been observed but, unfortunately, no sound theory has been formulated.
The purpose of this research was to determine the effect, if any, of changes in structure upon the amount of urea required to adduct with esters. The change in structure consisted of changing the …
The Urea Adducts Of Certain Esters Containing Twenty Carbons, Donald Eugene Johnson
The Urea Adducts Of Certain Esters Containing Twenty Carbons, Donald Eugene Johnson
University of the Pacific Theses and Dissertations
Urea has the interesting and unexpected property of forming solid complexes with many straight-chained organic compounds. So selective is the formation of these complexes with linear aliphatic compounds that it provides a means of separation form the analogous branched and cyclic compounds. Linear esters derived from normal saturated and unsaturated esters give adducts also but not to the same extent. Although many linear aliphatic compounds form adducts, the compounds so formed have varying degrees of stability depending on molecular weight, saturation and the shape of the molecule.
The purpose of this investigation is to determine the effect of the position …
Urea Adducts Of The Esters Of Stearic Acid, Paul Elliott Greene
Urea Adducts Of The Esters Of Stearic Acid, Paul Elliott Greene
University of the Pacific Theses and Dissertations
Urea forms crystalline complexes with n-alkanes and their liner derivatives but not with most branched and cyclic hydrocarbons and their derivatives. The compounds are stable enough to be used in separating these types of aliphatic compounds from their branched and cyclic analogs. Linear esters derived from normal saturated acids give adducts as expected. Urea complexation was found to be of great importance in the purification and separation of unsaturated esters of high molecular weight.
The object of the present research was to investigate the compositions of urea adducts of various long-chain esters, approaching the class of waxes, to test various …