Oxidation of cyclopentene catalyzed by phosphotungstic quaternary ammonium salt catalysts

Abstract

A series of phosphotungstic quaternary ammonium salts, Q 3 (PW 12O 40) and Q 3(PW 4O 16) [Q = (C 5H 5)N +(C 16H 33), (C 16H 33)N +(CH 3) 3, (C 4H 9) 4N +, and (CH 3) 4N +], were used as the catalysts in oxidation of cyclopentene. The catalysts [(C 5H 5)N(C 16H 33)] 3(PW 4O 16) and [(C 16H 33)N(CH 3) 3] 3(PW 4O 16) showed high catalytic activity in the selective oxidation of cyclopentene while using H 2O 2 (50%) as an oxidant and 2-propanol as a solvent. The oxidation products mainly consisted of glutaraldehyde, cis-1,2-cyclopentanediol and trans-1,2-cyclopentanediol. The above-mentioned two catalysts were dissolved completely in the reaction medium during the catalysis process and precipitated themselves from the reaction system after reaction, showing the characteristics of reaction-controlled phase-transfer catalysis. The types of quaternary ammonium cations and the phosphotungstic anions in phosphotungstic quaternary ammonium salts affected catalytic activity.