Effects Of Structure And Composition Of Catalyst From Bio-shell On The Catalytic Activity

Biomass crustaceans such as shrimp, crab and turtle shell are natural organic/inorganic composite materials that through thousands of years of biological evolution in nature, Biomass crustaceans have peculiar structure and properties of different components-calcium carbonate and other minerals showed a honeycomb but the gap between layers were filled with chitin and protein. There is a huge difference between their compositions on thermal stability, under the suitable carbonization temperature, the part of the organic matter gasification, the porous framework structure of organic/inorganic composite materials were obtained, and then the materials were modified by chemical modifier KF to build high catalytic activity of the active site on the surface. High-performance catalytic materials that needed to meet the bio-diesel production were obtained.The catalyst surface area was determined by BET method, the carbonization process weightless situation and catalyst of thermal stability of biological crustaceans were studied by thermogravimetric analysis, catalyst surface molecular functional group was analyzed by infrared spectroscopy, the composition of catalyst was analyzed by the elemental analyzer, activity of the catalyst was evaluated by the transesterification of rapeseed oil and methanol, the catalytic activity prepared in difference condition was evaluated by the biodiesel yield. The results show that the carbonization temperature from300℃to450℃, all of three crustaceans have the largest surface area, turtle shell was100m2/g, shrimp and crab were about25m2/g. when the carbonization temperature was from450℃to500℃, The efficiency of the catalyst was the highest, that indicate the activity of the biological crustacean solid catalyst not only related with the catalyst specific surface area of the but also formation conditions of catalytic active site has greater influence. Through structure and composition of the catalyst, the possibility of catalyst active sites formation mechanism is:chitin was dehydrated in a suitable temperature to generate double bonds and carbonyl groups as cycle structure with propylene ketone composition,, there is an addition reaction between the F-of KF and propylene ketone structure in process of activation, then enol anion was formed and enolate anion f rearranged to the a carbonyl carbanion, the carbanion reacted with methanol to generate the methoxy anion, methoxy anion attack on the carbonyl of the fatty acid esters of glycerol to generate fatty acid methyl esters and glycerol.The relationship of the biological of crustaceans base catalyst transesterification and structure, composition, performance was discussed and the formation mechanism of the catalytic activity was expounded, that provides a new theoretical and experimental evidence for the discovery or synthesis of new catalyst materials, revealing the rule of heterogeneous catalytic transesterification reaction.