The effect of primary, secondary, and hindered-secondary hydroxyl groups on reactions and temperature profiles of polyurethane gels was investigated and modeled using a computer simulation that simultaneously solves over a dozen differential equations. Using urethane gel reaction temperature profiles of the reference compounds 1-pentanol, 2-pentanol, and Voranol 360 reactivity parameters were determined for reference primary, secondary, and hindered-secondary hydroxyl moieties. The reaction parameters, including Arrhenius constants and heats of reaction, were consistent with previous values reported in literature. The approach of using fractions primary, secondary, and hindered-secondary hydroxyl content to characterize reactivity sets the basis for a powerful approach to simulating/predicting urethane reaction performance with limited data on new polyols and catalysts. This code can be used for all polyols, as the kinetic parameters are based on the fraction primary, secondary, and hindered-secondary alcohol moieties, not the type of the polyol. Kinetic parameters are also specific to catalysts where at least one parameter specific to each catalyst is necessary to simulate the impact of that catalyst. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40388.