Synthesis of Aromatic Aldehydes and Carboxylic Acids by the Oxidations of Polyaromatic Hydrocarbons

本研究针对多环芳香族化合物氧化合成醛、酮、醇、羧酸等含氧产物进行了研究。具体地说，我们对2，6-二烷基萘的光氧化进行了广泛的研究，在常温下，N-溴代丁二酰亚胺在不同的溶剂中进行了芳烃上侧链甲基的光溴化反应。在苯溶剂中进行可见光照射，可以有效地提高反应的选择性和产物的提纯效率。1，4-，1.8-，2，3-和2，6-二甲基萘、4，4‘-二甲基联苯和对二甲苯分别与2，2摩尔当量的N-溴代丁二亚胺进行光溴化反应，得到相应的双(溴甲基)芳烃。在上述二甲基芳烃与1.1摩尔当量的N-溴代丁二酰亚胺的光溴化反应中，也以较高的产率得到了(溴甲基)-甲基芳烃。2-溴-6-甲基萘和2，6-二(溴甲基)萘分别以较高的产率分别得到2-羟甲基-6-甲基萘和2，6-二(羟甲基)萘。2，6-二烷基萘部分选择性地加氢生成相应的2，6-二烷基四氢萘。这些化合物以钴、锰和溴化物为催化剂，用分子氧进行氧化反应，得到混合产物。还研究了苯基环己烷的氧化反应。主要产品为苯甲酸甲酯、谷氨酸二甲酯和丁二酸二甲酯。

This study has been carried out aiming at the syntheses of oxygenated products such as aldehydes, ketones, alcohols and carboxylic acids by the oxidations of polyaromatic compounds. Specifically, the photooxidation of 2, 6-dialkylnaphthalenes was extensively studied.Photobromination of side-chain methyl groups on arenes with N-bromosuccinimide was carried out in various solvents at ambient temperatures under nitrogen. Visible light irradiation in benzene solvent was extremely effective in increasing the selectivity of the reaction and the efficiency for product purification. The photobromination of 1, 4-, 1.8-, 2, 3- and 2, 6-dimethyinaphthalenes, 4, 4'dimethylbiphenyl, and p-xylens with 2, 2 mol equivalents of N-bromosuccinimide quantitatively afforded the corresponding bis(bromomethyl)arenes, respectively. The(bromomethyl)-methylarenes were also obtained in good yields in the photobromination reactions of the above dimethylarenes with 1.1 mol equivalents of N-bromosuccinimide. The hydrolysis of 2-bromo-6-methylnaphthalene and 2, 6bis(bromomethyl)naphthalene gave 2-hydroxymethyl-6-methylnaphthalene and 2, 6-bis(hydroxy methyl)naphthalene respectively in good yields.2, 6-Dialkylnaphthalenes were partially and selectively hydrogenated to yield corresponding 2, 6dialkyltetrahydronaphthalenes. The oxidations of these compounds by molecular oxygen with cobalt, manganese and bromide as catalysts gave mixtures of products. The oxidation of phenylcyclohexane has been also studied. It gave methylbenzoate as a major product together with dimethyl esters of glutafic acid and succinic acid.