Preparation And Research On The Catalytic Oxidation Performance Of Graphene-dinuclear Metal Phthalocyanine Composite Catalyst

Aromatic ketones are important chemical raw materials,they are produced by direct oxidation of aromatics by air in the industry,but their yield is low,therefore,it is important to study a new catalyst to increase the yield of aromatic ketones and aromatic alcohols.Metal phthalocyanine exhibits excellent performance in catalytic oxidation,it as a catalyst can overcome the disadvantages of high cost of precious metals in catalytic oxidation,however,it tend to aggregate in solution,so that the catalytic activity is reduced.It is an effective way to improve its catalytic performance by loading the phthalocyanine on the support.Graphene is a new type of carbon material,it has the features of high chemical stability,large specific surface area and strong electron migration ability.Graphene oxide is a special derivative of graphene,its surface has lots of oxygen-containing functional groups and has strong modifiable properties,it can be covalently linked with the metal phthalocyanine.The binuclear metal phthalocyanine has better catalytic performance than the mononuclear metal phthalocyanine in catalytic oxidation.but there are no reports on the covalent links of graphene-binuclear phthalocyanine.In this paper,a covalently-linked graphene oxide-mono/dinuclear metal phthalocyanine composite catalyst was designed and synthesized,and its performance on the catalytic oxidation of ethylbenzene with t-butyl hydroperoxide was studied.Firstly,4-nitrophthalonitrile was synthesized from phthalic anhydride,and pyromellitic nitrile was synthesized from pyromellitic anhydride as the raw material,its structure was confirmed by the melting point determination,TLC and ~1H-NMR.Nitro mononuclear phthalocyanine(Co,Fe,Cu)and nitro dinuclear phthalocyanine(Co,Fe,Cu)using4-nitrophthalonitrile and pyromellitrrene as raw materials were synthesised by DBU liquid-phase catalytic method.Their structures were characterized by FT-IR,UV-vis,mass spectrometry and ~1H-NMR,and their metal contents were determined.Graphene oxide was prepared by modified Hummers method,Its structure was characterized by FT-IR and XRD.Covalently-linked graphene oxide-mono/binuclear metal phthalocyanine composite catalysts were prepared by 3-mercaptopropyltrime-thoxysilane,and were characterized by FT-IR,XRD,XPS,TEM and TG.The loading of different metal phthalocyanines is an important factor affecting the catalytic performance of composite catalysts,therefore,Graphene oxide and coupling agent metal phthalocyanine composite catalysts with different mass ratios were prepared,and the metal content in these composite catalysts was measured.The catalytic performance of mono/binuclear phthalocyanine of different metals and different composite catalysts were studied,the results show binuclear cobalt phthalocyanine has the highest catalytic activity,and the catalytic activity of graphene oxide-binuclear cobalt phthalocyanine is higher than that of dinuclear cobalt phthalocyanine.Through careful examinations of different conditions,the optimum conditions to catalytic oxidation of ethylbenzene using composite catalyst as catalyst were established.Comparison of the catalytic performance of composite catalysts with different mass ratios showed that the best mass ratios was 1:4.5.In the composite catalysts with different linkages,covalently linked graphene oxide-binuclear cobalt phthalocyanine has the best catalytic activity.