Synthesis of “Silica – Carbon Nanotubes” Composite and Investigation of its Properties

A new method for synthesis of CNT-SiO2 composite was developed. Oligomethylhydridesiloxane (OMHS) was used as the SiO2 precursor. The presence of active hydrogen in the composition of OMHS made it possible to obtain chemical interaction between the surface of carbon nanotubes and the deposited silica layer. The effect of the silica film on the CNT oxidizing ability was studied. It was found that the oxidation rate of the CNT-SiO2 composite decreases approximately by an order of magnitude in comparison with as-prepared CNT. The morphology and structure of amorphous silica obtained after oxidation of the CNT-SiO2 composite were studied. The thermal stability of the CNT-SiO2 composite was also studied. The CNT-SiO2 composite was found to be thermally stable up to temperatures of 1100-1200 ºC. An increase in the calcination temperature to 1300 ºC leads to segregation of the CNT-SiO2 composite into individual components: CNT and SiO2 particles

Anthraquinones formation on zeolites with BEA structure

Zeolites with BEA structure are in focus mainly in the field of conversion of hydrocarbons. However, their unique physico-chemical properties let to suppose that these systems can be successfully used in reactions of organic synthesis. Such zeolites can be used as catalysts for the synthesis of large organic molecules. The interaction of phthalic anhydride with aromatic hydrocarbons is a subject for investigation, both for science purposes and for industrial applications. The use of zeolites in this reaction is an example of the acylation of aromatics on solid-acid catalysts; on the other hand, such a study creates the possibilities of developing more appropriate technology for the production of anthraquinone compounds. This chapter presents experimental material on the investigation of catalytic properties of zeolites with BEA structure in anthraquinones formation. The chapter presents a study of the interaction of both initial reagents and reaction products with acid sites of zeolite using IR technique. On the base of the obtained data, a mechanism of formation of reaction products was proposed. The catalytic properties of zeolite with BEA structure were examined in the reaction in the range of 225–500°C. Increasing the reaction temperature can cause the decomposition of not only anthraquinone molecules but also of phthalic anhydride and benzoylbenzoic acid, which can lose CO and CO2 giving benzophenone, biphenyl, and 9-fluorenone as reaction products