Vaporisation of a Pyrophoric Substance: Borane Triethyl

A flow-through system is proposed for studying the evaporation rate of a pyrophoric liquid, borane triethyl (BTE), under various conditions of pressure and volume flow of inert (nitrogen). First, some basic aspects of the problem are presented. It is shown that the BTE partial pressure tends to a limit ing value that is lower than the saturated vapor pressure that can be obtained in closed box system, and that is a function of pressure and volume flow of inert. When this limiting pressure is reached, the mass flow rate of BTE vapor leaving the flow-through system is constant and equal to the evaporation rate. Therefore, such a procedure can be used for generation of controlled and stabilized BTE vapor-inert mixtures. Next, some experiments, conducted using strict precau tions, are presented. They allow for the determination of an evaporation constant for different initial masses of BTE liquid, and for different pressures and volume flows of inert.