Synthesis Of ?-Titanium Phosphate Intercalation Compound And Its Catalytic Property In Cyclohexanone Ammoximation

?-Zirconium phosphate had attracted lots of researchers'attention since it was successfully synthesized in 1964.A lot of its similar partners also synthesized later,and finally formed a new category:?-tetravalate metal phosphates(or arsenates).They are typical cationic layered compounds which have lots of protons in the interlayer space,and thus own a strong capability of cation exchange.Small sized cations can exchange with these protons directly.Big sized cations however,are difficult to get into the narrow interlayer space direcly because of steric hindrance.By contacting this category with amine vapor or water solution,the obtained intercalated compound can provide much larger interlayer distance,making future induction for big sized cations possible.In this study,?-titanium phosphate was taken as an object to intestigate a new way to achieve the intercalation reaction:synthesizing various kinds of salt solutions composed of amine and acid,then mixing?-titanium phosphate with them in order to accomplish ion exchange of the cations with interlayer protons and thus obtain the intercalated compound.By using multiple kinds of characterization methods,it was revealed that the intercalation result was decided by the species of the acid parts of the salts which were applid in the synthesis of salt solutions:acid radicals of the polyprotic acids could play a role of buffer system which abosorbed the de-intercalated protons,resulting in the increase of electrostatic repulsion between the negatively charged layers due to the consecutive loss of interlayer protons,so that the interlayer distance was correspondingly increased and making the alkylammonium cations could be introduced into the interlayer space which were originally difficult because of their size,and finally obtained the intercalated product.On the other hand,the salts of strong acids did not have this property so that they could not trigger the intercalation process,which were proved by the characeterization results.Further study showed that,this ion exchange intercalation might probably be complicated,since that it was not every polyprotic weak acid salt could realize the goal of intercalation:the particular cases of cation radical and acid radical were proved to be exist,this was probably assigned to the synergistic effect,size,ridigity,etc.of the ions.Another part of this study was the investigation of catalyzing cyclohexanone ammoximation by using the catalyst of?-titanium phosphates which were experienced ion exchange operations.Investigation revealed that?-titanium phosphate exchanged with alkylammonium cations exhibited better hydrophobicity than the original one,however,deu to the loss of interlayer protons,the catalytic activity of the catalyst was declined which was shown as drop of selectivity of cyclohexanone oxime.In addition,the catalytic activity of alkali metal cations Na~+and K~+exchanged?-titanium phosphates were also investigated.The results revealed that the catalyst exchanged with Na~+and K~+had lost most of its catalytic capability.Study indicated that the catalytic activity of?-titanium phosphate positively correlated with the amount of interlayer Br?nsted active sites,and this was different from what showed by TS-1 zeolite which owned two kinds of Br?nsted active sites.