Reactivity of Unsaturated Hydrocarbons Via Adiabatic Calorimetry

Abstract

Selected olefins, diolefins, and alkynes have been examined via adiabatic calorimetry to understand the behavior of these species as a function of temperature. APTAC (Automatic Pressure Tracking Adiabatic Calorimeter) and Vent Sizing Package (VSP) testing has revealed the uncatalyzed reactivity of these compounds. Conjugated diolefins such as cyclopentadiene, 1,3-butadiene, and isoprene show trends consistent with Diers-Alders condensation to form dimers, trimers, etc. At elevated temperatures, the oligomers/polymers formed from these species apparently decompose exothermically. Several of the alkynes react at temperatures above 200°C and ultimately approach temperatures of 900°C. A conjugated alkene-yne, on the other hand, shows reactivity comparable to butadiene (i.e., onset temperature of 80-90°C). In contrast to these results, straight-chain olefins exhibit no exothermic behavior for temperatures up to 340°C.