Novel approach of thionyl chloride detection and disposal using a benzimidazole-based derivative: perspectives and proposals

Abstract Benzimidazoles are important heterocyclic compounds that exhibit a wide range of pharmacological and biological properties. Among all, sensitivity to Lewis acids provide a possibility to act as a fluorescent detectors for senzing the cathions, radicals, highly reactive low-molecular species with hazardous effects to environment and human health. Herein, we present the design and synthesis of N -((1 H -benzo[ d ]imidazol-2-yl)methyl)cinnamamide ( I ) for the detection of readily reactive thionyl chloride (SOCl 2 ). Treatment of SOCl 2 with a novel benzimidazole-based compound I is accompanied by immediate color change. Although the process is irreversible the change noticeable by eye is profitable for a simple and rapid protection against the SOCl 2 exposure at amounts harmful for surroundings and body. In the context of environmental issue, the chemical reaction between the detector I and thionyl chloride is beneficial for the safe waste disposal. Thionyl chloride is recaptured in the structure of I throughout the reaction leading to a formation of stable compound II . Incorporation of residual traces of SOCl 2 into the structure of organic-type detector I represents effective route to achieve non-reactive and non-damaging derivatives. Accordingly, the organic non-liquid waste is subsequently stored and disposed in a safe manner.