Study On Catalytic Oxidation Of Cyclohexene To Adipic Adic With Quaternary Ammonium Salts Of Phospho-tungstic Acid

In this work, H₂O₂ with ample supply in China was used as oxidant in the synthesis of adipic acid from cyclohexene. And we mainly carried out the following aspects of research works:1. Based on transition metal catalytic oxidation theory, the structure design in the molecule of W(VI) catalyst was carried out in allusion to the particularity of cycloalkene-H₂O₂ reaction system. The amphiphilic structure of quaternary ammonium ions was encased in the excellent oxidation activity and selectiveity of phospho-tungstic acid root that formed quaternary ammonium salts of heteropolyacids. These quaternary ammonium salts of heteropolyacids were characterized by IR and elemental analysis.2. The filtering catalysts was used in the oxidation of cyclohexene to adipic acid. The result indicated that, in the absence of cocatalysts and acids, the catalytic activity have been very high if cation of quaternary ammonium phospho-tungstic acid was cetypyridine quaternary ammonium ions.3. The filtering catalysts was used in synthesis of adipic acid reaction. The key factors influencing the oxidation were also studied, such as reaction time, reaction temperature, mole ratio between H₂O₂ and cyclohexene, the amount of catalysts. Orthognol technique was used twice to optimize the reaction conditions, optimal synthesis condition was detailed as: reaction time 5.5 h, reaction temperature 90 ℃, n (H₂O₂): n (C₆H₁₀) - 5.5:1 (based on 0.045 mol cyclohexene), amounts of catalyst was 0.3 mmol. On the condition, the repetition of experiment result were better, the average yield of adipic acid was 73.88%, the average recovery rate of catalyst was 51.82%.4. The recovery catalyst was used in the oxidation of cyclohexene to adipic acid oxidized by H₂O₂. After catalysis cycle was quintic, catalysis activity didn't reduce. The new catalyst and the used catalyst were analysed by IR, and found IR spectra of recovery catalyst in accord with IR spectra of the Keggin structure of [PW₁₂O₄₀]^3-.The points of this work were listed as follows:1. The green oxidant H₂O₂ is used in this work with the reductive production of H₂O. So there is no baneful materials to release and it can be ascribed to a kind of green progress.2. A series of quaternary ammonium salts of phospho-tungstic acids catalysts were systematically studied in the oxidation of cyclohexene. And the catalysts could be mostly recovered and utilized.