Reactive Chemical Screening - A Widespread Weak Link?

Abstract

It is an accepted practice in the fine chemical industry that feeds, products and intermediates for which thermal stability data is unavailable, are first “screened” and depending on the results, might then be subjected to a more detailed evaluation (typically involving adiabatic calorimetry). The reason for this two-stage approach is economic – the costs of subjecting all chemicals to detailed scrutiny would be prohibitive. It is frequently not appreciated, however, that this places a tremendous importance on the screening test – if this allows potentially hazardous materials to slip through undetected, the availability of more accurate downstream techniques is of no use. This paper will present a critical review of the screening methods most widely used and also describe some industrial accidents that have arisen despite such testing. The basis of a more reliable screening method will then be presented as well as results from a recently produced instrument, the TSU (Thermal Screening Unit), that incorporates these features.