Use of porphyrin-containing polymers of intrinsic microporosity as selective photocatalysts for oxidative detoxification of chemical warfare agent simulant

Abstract

Porphyrin-based polymers of intrinsic microporosity (PIMs) in photocatalytic degradation of a mustard-gas simulant (2-chloroethyl ethyl sulfide (2-CEES)) was demonstrated. Under blue-ultraviolet (UV) light-emitting diode (LED) irradiation, porphyrin-based PIMs PP-H2 and PP-Zn(II) worked as effective heterogeneous photocatalysts for oxidation of 2-CEES. Solvent played an important role in the conversion and selectivity of 2-CEES oxidation. When AcCN was used as a solvent, PP-H2 and PP-Zn(II) demonstrated complete conversion of 2-CEES in 30 and 50 min, respectively, whereas they showed complete conversion at 60 and 70 min, respectively, when MeOH was used as a solvent. Moreover, these PIMs produced 2-chloroethyl ethyl sulfoxide (2-CEESO) as a major product with small amounts of 2-chloroethyl ethyl sulfone (2-CEESO2), ethyl methoxyethyl sulfoxide (EMSO), and vinyl sulfoxide (EVS) as side products in most solvents. However, when MeOH was used as a solvent, highly toxic 2-CEESO2 was not observed as a side product. Furthermore, these PIMs showed no significant changes in photocatalytic activity even after five cycles of reuse, indicating their high stability. Thus, the series of PIMs prepared herein can perform well as heterogeneous catalysts in photooxidation of 2-CEES under blue-UV LED light, with PP-H2 being the most effective oxidation catalyst, leading to fast conversion and high selectivity.