A Versatile WO ₃ ‐Based Catalyst Toolkit for One‐Step Oxidative Cleavage of Unsaturated Fatty Acids and Esters Into Azelaic and Nonanoic Acids

Oxidative cleavage of unsaturated fatty acids can break the carbon chain at the double bonds, generating shorter‐chain and high‐value products. This study replicated four oxidative cleavage methods using oleic acid to produce azelaic acid and nonanoic acid. Based on the EcoScale assessment, the one‐step oxidative cleavage method using WO 3 /Na 2 SnO 3 as a catalyst achieved the highest score and was selected for further optimizations. Under solvent‐free conditions, the yields of nonanoic and azelaic acid increased from 68.1% and 64.1% to 75.4% and 79.0%. A hot‐water‐assisted extraction method was developed to recover products from the heterogeneous system. GC–MS analysis showed that the purities of nonanoic acid and azelaic acid in the oil phase and aqueous phase reached 79.5% and 85.6%, respectively. The catalyst WO 3 was further modified with cetyltrimethylammonium bromide (CTAB), which improved the yields of nonanoic acid and azelaic acid to 82.7% and 86.0%, respectively. The WO 3 ‐CTAB/Na 2 SnO 3 catalyst cocktail was tested over four recycling rounds, with products yields and purities remaining above 80.0% and 75.0%, respectively. This catalytic system was also effective for the oxidative chain‐breaking of C18 unsaturated fatty acids and their methyl esters. This study provides an effective heterogeneous catalytic method for producing nonanoic acid and azelaic acid from unsaturated fatty acids and esters.