External Catalyst‐Free Oxidation of Benzyl Halides to Benzoic Acids Using NaOH/TBHP in Water.

An efficient and metal‐free methodology for the oxidation of benzyl halides to benzoic acids using an inexpensive and green oxidant (TBHP) in aqueous basic medium has been developed. This protocol offers an excellent way to avoid adding catalysts and involves the use of an in‐situ generated halide ion as catalyst. It is also the first report on the oxidation of benzyl iodides to benzoic acids. A series of carboxylic acids were prepared from benzyl halides in high yields under mild reaction conditions by this method which does not require chromatographic purification. Gram scale reactions for the synthesis of the carboxylic acids in good yields have been successfully carried out using benzyl chloride, bromide and iodide. As an industrial application, the synthesis of a key monomer used for the synthesis of polyethylene terephthalate (PET), i. e. terephthalic acid (PTA), has also been accomplished in good yields. [ABSTRACT FROM AUTHOR]