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The title heterocyclic compounds have been prepared by the addition of sodium azide to arylethynyltriphenylphosphonium halides in dimethylformamide. In hot basic aqueous solution these ylides hydrolyze to give 4-aryltriazole anion and triphenylphosphine oxide. More notably, the ylides are nucleophilic: displacements of halide from ethyl iodide, benzoyl chloride, ethyl chloroacetate, ethyl /3-chloropropionate, 2,4-dinitrobromobenzene, and mercuric chloride and Michael additions to ethyl propiolate have been realized. In all of these examples, the point of attack is exclusively at the 2-nitrogen of the ylide. CNDO calculations on the hypothetical unsubstituted l,2,3-triazol-4-ylphosphorane indicate a charge density in the molecule which is consistent with a mesoionic or ylide structure.

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Table 1 -Properties of EVOH films.Sorption of volatile compounds by ethylene-vinyl alcohol copolymer (EVOH) films from an aaueous solution was investigated to evaluate the merit of their use fdr food packaging. With rggard to EVOH, equilibrium swelling values gave rise to a bimodal solubility parameter distribution with maxima at 8 values of 8.5 assigned to ethylene units and 14.5 to vinyl alcohol units. Comparing distribution ratios of EVOH with those of middle-density poIyethylene (MDPE), the ratios were 1:lOO for terpene hydrocarbons, 1:lO for esters, 1:2 for alcohols, and almost 1:l for aldehydes. By biaxial orientation of EVOH film, the sorption could be depressed below 60%. These results suggested EVOH films are more appropriate than MDPE for food container lining.