4,4′-Bis(Dimethylamino)Thiobenzophenone as a 2-Chloroethylethylsulfide Vapor-Sensing Coating for Optical Based Microsensors

Abstract

The chromogenic detector reagent, 4,4′-bis(dimethylamino)thiobenzophenone (TMK), has been studied as a solid-state coating for sensing 2-chloro-ethylethylsulfide (CEES) vapor. The type of solid reaction support is a critical factor affecting both the stability and performance of the coating; alumina is the preferred support. When monitored with a fiber-optic spectrophotometer, the TMK coating on an alumina support was found capable of detecting CEES at concentrations down to the low ppm level. Unstabilized TMK coatings were found to be highly susceptible to photodegradation. Photostability was improved significantly by including 2,6-di-tert-butylphenol in the coating formulation.

Key Words:

• 4,4′-bis(dimethylamino)thiobenzophenone
• 2-chloroethyl-ethylsulfide
• microsensor coating
• alumina
• chromogenic vapor detection