SIDE REACTIONS IN THE FORMATION OF POLYURETHANES - MODEL REACTIONS BETWEEN PHENYLISOCYANATE AND 1-BUTANOL

The following side reactions occurring in the formation of polyurethanes were modeled: a reaction of excess phenyl isocyanate either with 1-butanol in 1,4-dioxane and in bulk, or with n-butylphenyl urethane or water in dioxane catalyzed with dibutyltin dilaurate that leads to the formation of n-butyl- alpha , gamma -diphenyl allophanate, N,N prime -diphenylurea, and 1,3,5-triphenylbiuret. The reaction products were determined quantitatively by means of liquid chromatography. The rate and equilibrium constants were calculated at various temperatures and various initial ratios of functional groups.