金属卟啉与过渡金属盐分步催化四氢萘合成α-四氢萘酮及反应机理

Synthesis of α-Tetralone from Tetralin by Metalloporphyrin and Transition Metal Salt Tandem Catalysis and the Reaction Mechanism

对以四氢萘为原料制备α-四氢萘酮的工艺进行了研究.反应分两步进行:首先以金属卟啉为催化剂催化空气氧化四氢萘,得到主要成分为α-四氢萘过氧化氢和α-四氢萘酮的氧化产物;然后以过渡金属盐为催化剂,将氧化产物中的α-四氢萘过氧化氢定向分解为α-四氢萘酮.结果表明,四氢萘的金属卟啉催化氧化产物主要是α-四氢萘过氧化氢和α-四氢萘酮,仅得到微量的α-四氢萘醇.含过渡金属CuⅠ和FeⅡ离子的盐类可以高选择性地将四氢萘氧化产物中α-四氢萘过氧化氢定向转化为α-四氢萘酮,FeⅡ离子的活性最高.详细考察了不同金属卟啉及其浓度、温度对催化氧化四氢萘的影响;考察了不同金属离子及其浓度、温度对分解过程的影响.对金属卟啉的催化氧化机理及过渡金属离子分解α-四氢萘过氧化氢机理进行了探讨.

An efficient two-step preparation of α-tetralone from tetralin was studied. First, tetralin was oxidized to α-tetralin hydroperoxide with air in the presence of a metalloporphyrin catalyst. Second, a catalytic amount of either water-soluble iron salts or copper salts was added to the resultant α-tetralin hydroperoxide solution to convert α-tetralin hydroperoxide into α-tetralone.The major product of oxidation catalyzed by metalloporphyrin was α-tetralin hydroperoxide, and only a minor amount of α-tetralone and trace of α-tetralol were formed. Simple salts such as Cu^Ⅰ and Fe^Ⅱcould efficiently decompose α-tetralin hydroperoxide to α-tetralone, and best result was obtained with ferrous ion. The influence of the metal ions, catalyst amount, and reaction temperature on both the tetralin aerobic oxidation and the decomposition of α-tetralin hydroperoxide was studied. Possible mechanisms for the oxidation of tetralin and the decomposition of α-tetralin hydroperoxide were proposed.