Highly Reactive Heterogeneous Nanofibers Catalyst based on [Mo₁₅₄] Clusters for Green Aerobic Oxidation of Sulfur...

Due to the increasing chemical and biological threats posed by terrorist attacks, there is a need to design and prepare nanofibers (NFs) with the ability to neutralize CWAs. For this purpose polyacrylonitrile NFs and polyoxomolybdate [Mo₁₅₄] (abbreviated as PAN NFs/[Mo₁₅₄]) as a heterogeneous catalyst was prepared by electrospinning method with a diameter of about 100nm.

The PAN NFs/[Mo₁₅₄] catalyze the selective aerobic oxidation of sulfur mustard stimulants, such as 2-chloroethyl ethyl sulfide (2-CEES) and 2-chloroethyl phenyl sulfide (2-CEPS) under green and "ambient" conditions (25 °C, 1atm O₂) in the presence of ethanol with high efficiency and selectivity. 2-CEES was selected as a model reaction to optimize the parameters of the reaction.

The progress of the reaction was evaluated after different times using GC-FID, GCMS and TLC. The reaction product was also confirmed by ¹H-NMR spectroscopy.

The aerobic oxidation results of 2-CEES showed that PAN NFs/[Mo₁₅₄] have a conversion of 98% to produce only a nontoxic product, 2-CEESO with the selectivity of 100% after 45min. The results were performed using [Mo₁₅₄] without any PAN NFs for comparison whereas [Mo₁₅₄] converts only 52% of 2-CEES under identical conditions.

Heterogeneous PAN NFs/[Mo₁₅₄] catalyst was reused after washing with solvent up to 5 steps without leaching of [Mo₁₅₄] from PAN NFs and without any loss in efficiency due to the morphology of NFs. In addition to the recovery of PAN NFs/[Mo₁₅₄] in different cycles, the use of FT-IR, UV-Vis and TEM techniques confirms the stability and morphology of PAN NFs/[Mo₁₅₄] after the fifth cycle, 2-CEES oxidation. According to our information, this report is the first use of PAN NFs enriched with [Mo₁₅₄] for aerobic oxidation of sulfur mustard simulants.