Synthesis Of Cobalt-Based Nitrogen Doped Mesoporous Carbons And Its Application In Oxidative Coupling Of Alcohols

The design of novel materials is one of the most thriving subjects in the modern science research.Carbon materials are widely applied in many territories including materials,electrochemical,chemical catalysis and organic synthesis because of its low cost,high stability and excellent electrochemical performance.Contribution to its highly ordered pore structure,large specific surface area,good thermal stability and chemical stability,mesoporous carbon materials have shown the broad prospect in the fields of catalysis,adsorption,energy and so on.Furthermore,the introduction of heteratom and metals can enhance the catalytic performance of mesoporous carbon materials,by means of tuning material compositions,entire electronic structures and surface physicochemical properties,constructing new active sites to achieve many organic synthesis.Particularly,doping mesoporous carbons with nitrogen atom has made great progress on organic transformation field in recent years.In this dissertation,we design and synthesize a series of N-doped mesoporous carbon materials,and research the catalytic activity in the oxidition-coupling action of alcohols to esters or?,?-unsaturated ketones.we have designed and prepared a series of Co-N/m-C via the pyrolysis of Co-bidppz ?11,11'-bis?dipyrido[3,2-a:2,3-c]phenazinyl??precursor at different temperature,which have been applied in the direct aerobic oxidation of alcohols to esters under air and water is the only by-product.Among the catalysts,Cobalt-based nitrogen-doped mesoporous carbon?Co-N/m-C-900?show the best catalytic activity for this reaction.The catalyst exhibited a high turnover frequency?TOF?value(107.6 mol methyl benzoate mol^-1 Co h^-1)for the direct aerobic oxidation of benzyl alcohols to methyl benzoate,much higher than the transition metal based nanocatalysts reported in the literature which is contribution to the strong coordination between ultra-dispersed active cobalt species and pyridine nitrogen accompanied by the introduction of the mesoporous structure.Moreover,the catalyst exhibited the high yields for various structurally diverse alcohols,including benzylic,allyl,and heterocyclic alcohols.This oxidation process is readily amenable to gram-scale application.In addition,a preliminary evaluation revealed that Co-N/m-C-900 show the excellent stability that it did not appear the active loss significantly.In general,the transformation of alcohols to esters is expeditious,and high efficient catalytic system under mild condition.Then we prepared a new series of Cobalt-based nitrogen-doped mesoporous carbon materials by pyrolysis of cobalt phthalocyanine under different temperatures.Silica colloid is employed as the hard template to fulfill the mesoporous structures.One part of 15-20 layers of nitrogen-doped graphene coated cobalt core-shell structure and another vesicular mesoporous structure with no microscopic cobalt species constitute the material.The catalytic material was applied to the cross-coupling reaction of primary alcohols and secondary alcohols,showing medium to good catalytic effect for the synthesis of various ?,?-unsaturated ketones.The mesoporous structure plays a key role in the catalytic reaction.