Synthesis, Characterization And Application Of The Mesoporous Molecular Sieve Contain Phosphorus

Mesoporous molecular sieve aluminum phosphate was synthesized usingcetyltrimethylammonium bromide （CTAB） as a structure-directing agent and aluminumhydroxide, aluminum, isopropoxide phosphoric acid （85%）, as aluminum, phosphorus,sources,under the condition of acidity, basicity and the method of oriented agent. Andmodified by LaCl3. The composition, structure and surface physical and chemical propertiesof the samples were characterized by X-ray EDS analysis, inductively coupled plasma massspectrometry （ICP-MS）, elemental analyzer, fourier transform infrared spectroscopy （FTIR）,N2adsorption-desorption, NH₃chemisorption （NH₃-TPD）, small-angle X-ray diffraction（XRD）, scanning electronic microscope （SEM）, transmission electron microscopy （TEM）,thermogravimetric analysis （TG）, pyridine adsorption （FTIR） and so on.Synthesis method of hydrothermal: the typical worm-like layer structure of AlPO₄mesoporous molecular sieve was synthesized under the condition of basicity, TPD acid was0.1642mmol/g, surface area was308.5m²/g, pore volume was0.1336mL/g, and pore size4.761nm; The worm-like layer structure of AlPO₄mesoporous molecular sieve wassynthesized under the condition of acidic, TPD acid was0.3498mmol/g, surface area was309.4m²/g, pore volume0.2572mL/g, and pore size3.325nm.AlPO₄mesoporous molecular sieve was synthesized by the method of oriented agent TPDacid was0.0395mmol/g, surface area was235.3m²/g, pore volume0.4202mL/g, and pore size4.221nm.The La-AlPO₄mesoporous molecular sieve was synthesized by the method of orientedagent, the Structure was not changed, TPD acid was0.1184mmol/g, surface area was212.3m²/g, pore volume0.2401mL/g, and pore size4.535nm.The results of ICP and elementalanalysis showed that the yield were15.7%and1.81%of Al and La for La-AlPO₄.Alsoshowed that La has been join the AlPO₄skeleton structure. Experimental results show that,the BET surface area was lower, but acid amount and acid strength were enhanced of LaAPO₄compare to AlPO₄.Catalytic character of AlPO₄and LaAPO₄were evaluated using reaction of synthesis acetylsalicylic acid. The results showed that both of AlPO₄and La-APO₄molecular sieve had highcatalytic activity in synthesis of acetyl salicylic acid: under alkaline conditions transformation rate of salicylic acid was64%, under acidic conditions transformation rate of salicylic acidwas69%, transformation rate of salicylic acid was53%of AlPO₄was synthesized by orientedagent method, transformation rate of salicylic acid was80%of La-APO4.