Mesoporous Aluminophosphates And Titanosilicates Assembled From Preformed Precursors

Since the discovery of mesoporous aliminosilicates and silicates such as MCM-41 materials,which are synthesized by Mobil scientists,A great number of mesoporous materials have been successfully prepared.Notably,many aluminophosphates also have been synthesized through surfactant synthetic strategies.But most of the aluminatephosphates materials are of a low thermal stability,as limits their further applications in catalysis,adsorption and desorption. It is well known that the thermal and hydrothermal stability are of great importance to the recycle of catalytic materials.It has been reported that thermal and hydrothermal stability of orderd mesoporous aluminalsilicates could be improved significantly by the assemble of preformed aluminosilicate zeolite nanoclusters.Nevertheless,this method is only limited in silicate-based mesoporous materials.In order that we can make a great progress in the synthesis of mesoporous aluminophosphates materials,we will here show assembly of preformed aluminophosphate zeolite AlPO4-18 nanoclusters with the surfactant of cetitrimethylammoniun bromide(CTAB)can synthesize an ordered hexagonal mesoporous aluminophosphate(JLU-50).This material is stable.JLU-50 catains AlPO₄-18 primary units in its mesoporous walls,which is similar to other mesoporous materials prepared from zeolite nanoclusters.Furthermore,we also prepared mesoporous aluminophosphates captaining Fe(Fe-JLU-50)and Cu (Cu-JLU-50)using zeolite Fe-AlPO₄-18 and Cu- AlPO₄-18 seed solution as inorganic precursors.Catalytic results of hydroxylations of phenol and 2,3,6-trimethylphenol show that Fe-JLU-50 and Cu-JLU-50 are both active in oxidation of small and large molecules after calcination,which indicates the advantages of preparation of heteroatom-containing mesoporous materials by using zeolite seed solution.All the mesoporous materials synthesized from zeolite "seed solution" have some common structural characters including the thicker wall,disordered in some extent,zeolite-like connectivities in the wall.We also propose another method of combing the advantages of microporous and mesoporous molecular sieves except for preparation of mesoporous materials by using zeolite seed solution,which is ormation of mesoporous in zeolite crystals.Here,we prepare TS-1 crystal of uniform mesoporous channels using anion exchange resins (D201)as a shape-directing macro-templates and TS-1 zeolite seed solution,which is named as MTS-1.Although XRD of MTS-1 dosen't give characterized peaks of TS-1 crystals,the primary building units of TS-1 zeolite are present in MTS-1.Furthermore,N₂ adsorption-desorption isotherms of MTS-1 show the presence of mesoporous of 24 nm.In hydroxylation of phenol,MTS-1 shows similar activity to that of TS-1.And in hydroxylation of 2,3,6-trimethylphenol shows that mesoporous channels makes it easy that MTS-1 catalyses oxidation of large molecule.This indicates that MTS-1 combines the advantages of microporous and mesoporou molecular sieves.