Synthesis Of Mesoporous Molecular Sieves Templated By Ionic Liquid

The mesoporous molecular sieve is a kind of well used inorganic materials for its large pore diameter,high specific surface area and hydrothermal stability.The pore diameter is ranged from 2 to 50nm,and it can be adjusted based on usage ranging from 2 to 10 nanometer.In recent years,it has been used widly in catalysis field,especially the well-known effect in areas of hydrogenation and macromolecules catalytic oxidation. Meanwhile, because of its unique character, it can also be used as ion exchanger, absorbent and new functional materials.There are many different types of mesoporous molecular sieve,and the most studied and most widely used is MCM-41, which has the hexagonal symmetrical structure,and it is also one of the first to be synthesized among the mesoporous materials. The most common method is to use Cetyltrimethylammonium Bromide(CTAB) as template to synthesize MCM-41 under hydrothermal reaction. According to this method we can get products with high crystallinity,but for the higer reaction temperature(100～140℃),lower hydrothermal stability and wall thickness, it can not be a good application.Ionic liquid is a quaternary ammonium salt with molecular orientation assembly function, employed as template in synthesis of molecular sieves. Moreover, using it as a template in synthesis of mesoporors molecular sieves will be a novel attempt in ionic liquid field.This thesis, based on the literature investigation and previous research of our experimental group, aims to synthesize MCM-41 with pure silica and hetero atom, then to optimize the reaction condition, and improve the performance of mesoporous molecular sieves. Based on the above ideas, this paper research will be proceed as follows:(1) To synthesize the ionic liquid 1-cetyl-3-methylimidazolium bromide which employed as template in synthesis of molecular sieves,characterize by IR.(2) To synthesize MCM-41 with CTAB and 1-cetyl-3-methylimidazolium bromide as template in the same conditions, respectively.according to the analysis we knew the sample synthesized by ionic liquid had higher specific surface area and pore wall thickness.(3) Mesoporous molecular sieves MCM-41 has been synthesized using 1-hexadecane-3-methyl-imidazolium bromide as a template. The effects of different Si sources, raw materials ratio, PH and temperature crystallization time on synthesis of MCM-41. The structure of MCM-41 was characterized by X-ray diffraction and N2 adsorption-desorption. FTIR,SEM.Results show that the best product MCM-41 would be obtained under the following reaction condition: sodium silicate as silica source, [C16mim]Br/SiO2=0.4, PH=10.5, reacting for 3 days at 80℃, calcinated for 6 h at 550℃.(4) To synthesize heteroatomed MCM-41 with 1-cetyl-3-methylimidazolium bromide,there are:Al-MCM-41,Ti-MCM-41,Cu-MCM-41. study the different materials ratio to synthesize the best product.