Synthesis And Characterization Of Series Of Dialkoxy Quaternary Ammonium Salt Soft Template Agents For Mesoporous Materials And Their Performance Research

Porous molecular sieves materials are a large family of inorganic materials.Due to the high thermal stability and large specific surface area,they constitute a kind of excellent adsorption agents,catalysts as well as carrier which have been widely used in petrochemical industry and other fields.Because the pore sizes of traditional micropore molecular sieve were usually less than 1 nm,which were not suitable for those chemical reactions involving large molecule.Therefore,development of mesoporous molecular sieve was an important branch of inorganic material field.In the early 1990s,Japanese scientists and Mobil scientists separately reported the synthesis of mesostructued silicates.In Mobil's report,quaternary ammonium cationic surfactants such as cetyltrimethylammonium bromide(C16H33N(CH3)3Br,CTAB)was first used as template to prepare highly ordered M41S mesoporous silicate molecular sieves under basic conditions.This kind of attractive material extends the uniform pore sizes from the range of micropore to mesopore.Over the past twenty years,scientists have summarized the synthetic laws based on the formation mechanism and synthetic methods of mesoporous molecular sieve,among which the selection of surfactant as soft template agent is one of the key aspects in the preparation of mesoporous molecular sieve,and the structure and properties of surfactants directly affect the structure,pore diameter,specific surface area and catalytic properties of the acquired mesoporous molecular sieves.Generally,different surfactant leads to generate different mesoscopic molecular sieves structures.In this paper,a series of cationic quaternary ammonium salt were designed and synthesized as soft template agents for mesoscopic molecular sieves preparation.The synthesized surfactants were expected to generate a new specific mesoporous molecular sieve materials,and to be used to control the pore sizes,specific surface area of mesoporous materials through varying the length of cationic surfactant hydrophobic chains.Toluene-4-sulfonyl chloride and alkyl fatty alcohol CnH2n+1OH(n= 12,14,16,18)generated alkyl p-toluenesulfonates in pyridine,then 3-dimethyl aminopropane-l 2-diol and methyl iodide were used to prepare a series of soft template agents for the preparation of mesoporous materials.The intermediate products and terminal products were characterized by 1H NMR,13C NMR,HSQC and MS.The CMC and ?cmc of these surfactants were measured by surface tension method.Surface properties showed that these cationic quaternary ammonium salt have high surface activity,which might be suitable as soft-template agents in the preparation of mesoporous molecular sieves.