Preparation And Catalytic Application Of The CNTs-Based Holistic Catalyst

Recently, a novel holistic catalyst of aligned carbon nanotubes layers over stainless steel mesh has received a great deal of attention in the scientific community because of their great potential in many applications. Previous work mostly focuses on preparing this CNTs-based structured catalysts and structural characterization, but feasibility studies of its application in chemical industry, especially in the field of applied catalysis, still needs to be explored.The research presented in the thesis make great advances on the controllable preparation, functionalization of the catalysis, as well as its usage on the transesterification reaction to produce biodiesel.Firstly, this work chooses a mild road to prepare this structured catalyst. The pretreated stainless steel mesh is loaded in the thermal CVD furnace for CNTs growth. Ferrocene acts as the catalyst precursor and benzene as the carbon source. The experiment is carried out at a temperature of 700℃ in an Ar/H2 gas atmosphere. After that, the CNTs on the stainless steel mesh are sulfurated with Na2Sx and oxidized by hydrogen peroxide to sulfonicacid. For this CNTs-based structured catalyst, there are numerous-C-SO3H covalent bonds on the surface as acid sites, which provide the electron-withdrawing force to resist desulfonation that displays more stable than other solid acid catalysts. In addition, this catalyst has superior properties of chemical durability and easily shaped.Secondly, bad this structured catalyst as fillers into a catalytic distillation column,20mm in diameter and 200mm in height The total amount of CNTs grown on the stainless steel mesh is about 2g with total surface area about 450 m2. The transesterification of methanol and soybean oil is carried out in the catalytic distillation column. The result shows that this structured catalyst has outstanding catalytic activity for transesterification of bio oils with methanol and surprisingly also for the synchronous conversion of glycerol to glyceric acid, glyceraldehyde, 1,1-Dimethoxyhexane and acrolein dimethyl acetal.Noteworthy that the performance of the process is much stable in 100 h of operation, and the morphology of the catalyst appears unchanged after 100 h reaction. Comparing with some results documented on the transesterification of bio oil with methanol, which required a large excess methanol at common conditions, the current method possesses overwhelming advantages by intensifying the reaction with simultaneous separation and synchronous transformation of glycerol.