The Synthesis Of Functionalized Mesoporous Materials And Amine Drugs Gas-sensing Properties Research

Ordered mesoporous materials,such as mesoporous silica and mesoporous carbon which have neat hole structure,large pore size and good hydrothermal stability,has been becoming the current hot topic in the field of mesoporous materials and has attracted more and more attention.Functionalized mesoporous materials which has better properties than the parent materials can be obtained by chemical modification.In this paper we chose ordered mesoporous materials SBA-15 and FDU-15 as the research object and discussed the gas sensing properties of functionalized SBA-15and FDU-15.1.Carboxyl functionalized FDU-15?FDU-15-COOH?and Carboxyl functionalized SBA-15?SBA-15-COOH?were synthesized as humidity sensing materials.Those materials were designed on the basis of hydrogen bond interaction between water molecules and carboxyl groups.The response characteristics of two materials to humidity and ammonia were compared.FDU-15-COOH were obtained by oxidation reaction with Ammonium persulfate?APS?.In order to obtain SBA-15-COOH,cyano functionalized SBA-15?SBA-15-COOH?was synthesized with?2-Cyanoethyl?triethoxysilane,Tetraethyl orthosilicate?TEOS?and P123 by co-condensation,And the templates?P123?was removed by 48 wt%H₂SO₄.The experimental results show that the existence of a large number of carboxyl and hydroxyl functional groups in FDU-15 after acidification treatment,Which promote the water molecules adsorption capacity on the surface of mesoporous materials by the hydrogen bonding adsorption.FDU-15-COOH revealed good sensitivity in low humidity conditions,the minimum detection limit is 10 ppm.At the same time we tested the response performance of FDU-15-COOH and SBA-15-COOH to organic amine which has amidation and hydrogen bonding,the results showed that two carboxyl functionalized mesoporous materials are not sensitive to ammonia neither organic amine.The results also verified the FDU-15-COOH has good selectivity for humidity detection.The molecular simulations of different binding sites were carried out by using the quantum chemistry software Gaussian and the enthalpies of adsorption of ammonia and organic amines on SBA-15-COOH and FDU-15-COOH materials were calculated.The results show that the absolute value of adsorption enthalpy is less than 40 kJ/mol,which belongs to physical adsorption,and the simulation results are consistent with the experimental results.2.Mesoporous TiO₂-SiO₂ functionalized with p-hexa-fluoroisopropanol aniline?HFIP?was designed and synthesized to achieve highly sensitive and selective sensing toward nerve agent simulant dimethyl methylphosphonate?DMMP?due to a hydrogen bonding between target DMMP and TiO₂-SiO₂-HFIP.The sensing experiments were conducted by coating compounds onto quartz crystal microbalance?QCM?transducers.It was found that the observed frequency shifts gradually and turned saturated in the range from 10 to 60 ppm.Gas sensing test results revealed that sensors had enhanced sensitivity due to the decoration of HFIP on TiO₂-SiO₂ in a ppb level.Furthermore,when the doping of HFIP reached 20 wt%,the sensors achieved the best sensing performance.In conclusion,the QCM sensor coated with mesoporous TiO₂-SiO₂-HFIP exhibited fast response,excellent reversibility and high selectivity to nerve agent stimulant DMMP vapor,implying that mesoporous TiO₂-SiO₂-HFIP may be a good candidate for sensing DMMP.3.Herein,we report novel ammonia gas sensor materials having aldehyde functional groups grafted onto the pore surface of highly ordered mesoporous materials SBA-15.The functional SBA-15 was synthesized via co-condensation of tetraethyl orthosilicate and formylsilanetriol using an amphiphilic block copolymer P123 as a structure-directing agent,in which formylsilanetriol was first synthesized through the reduction of 2-cyanoethyltriethoxysilane in the presence of diisobutylaluminium hydride.Furthermore,FT-IR and solid-state magic angle spinning nuclear magnetic resonance spectroscopy studies proved covalent anchoring of the aldehyde functional group onto the pore walls of SBA-15.The results indicated that the materials successfully kept their mesoporous nature after grafting of the aldehyde groups.Gas-sensing tests were investigated by coating the aldehyde-functionalized SBA-15 onto quartz crystal microbalance transducers.The results reveal that the sensors can be as promising candidates as ammonia detectors with desirable sensing behaviors,including high sensitivity(the QCM sensors were exposed to nitrogen stream until a stable baseline,fast response and good reversibility.4.Because of the Schiff base reaction of aldehyde group and organic amine,we grafted organic groups with FDU-15,and fabricated with QCM gas sensor to detect the organic amine gas.In order to obtain the functionalized FDU-15,firstly oxidiated group of FDU-15 and then treated with acylation,lastly the target product was obtained by addition reaction with benzaldehyde.The experimental results show that the good sensitivity and prefect selectivity of this 2-PEA QCM gas sensor,and the detection limit was below 10 ppm.The QCM sensor has a rapid response and recovery characteristics.Gassian software was used to simulate the interaction between 2-phenylethylamine and aldehyde groups.The reaction mechanism is Schiff base and the reason is the sensor has the characteristics of chemical selectivity,fast response and recovery.5.?-Fe₂O₃ is a body resisitance effect semiconductor material.In this paper,we use Fe2O3/FDU-15 composite to detect some gases.In order to obtain the composite material,the Fe?NO?₃.9H₂O and FDU-15 impregnated with ammonia solution at 60?about 3 h hydrothermal reactions,after heat treatment under the protection of nitrogen.Experimental results show that amorphous iron oxide was obtained when the annealing temperature is less than 400?,while Fe₂O₃/FDU-15 mesoporous composite can be obtained when the annealing temperature is higher than 400?.The gas sensing test results show that the frequency was increased when Fe₂O₃/FDU-15 was exposed to acetone and reducing gases such as ethanol,which was consistent with the experimental results.