Nitrogen-containing Organic Diphosphonic Acid - Tungstic Heteropoly Acid Preparation, Characterization And Nature Of The Study

Heteropoly compounds (HPC) are a kind of metal-oxide clustered coordination compounds solid materials whose cOordination centers are usually phosphoric acid and silicic acid. The molecular structures of these compounds that contain oxygen bridges are similar to the cage structure of molecular sieves. They are wide applied in many fields such as catalytic chemistry, analytic chemistry, material science, pharmaceutical chemistry because of their distinguishing features of strong acidity, strong oxidation, absorption and pseudo-liquid and so on. Synthesis of new type of heteropoly compounds is an important field of the research area of heteropoly acid chemistry. With the sustained efforts of many chemists in the world, a series of heteropoly compounds were prepared which have different structures and novel properties. An important method of synthesis of new type of HPC is introduction of organic or organometallic components into the molecular structure of HPC. The organic components can either be linked up the outer shells or inner skeletons of heteropoly anions. They can join in the molecules of HPC as the counter-ions too. Organophosphonic acids, especially those containing nitrogen atoms have the functions of complex and coordination. It is possible to prepare new type of HPC with these organophosphbnic acids as the coordination center. In the thesis, N-substituted bisaminoethylphosphonic acids and iminobisethylphosphonic acids DPA1-DPA7 were synthesized for the first time with ammonia, ethylenediamine, 1,6- hexamethylenediamine, piperazine, 2-aminoethanesulfonic acid (taurine), amino acetic acid (glycine) and n-butylamine; N- substituted bisaminomethylphosphonic acids and iminobismethylphosphonic acids DPA8, DPA9, DPA1O and N-methylphosphonic acid-N- ethylphosphonic DPA1 1 were prepared by means of Mannich type reaction; DPA12 was prepared with the alkylation of piperazine-N-ethylphosphonic acid. These bisphosphonic acids were characterized with IR spectrum and potential titration and their states in aqueous solution were also discussed. A series of N-contained or anobisphosphonotungstic heteropoly acids HPW1-HPW7, HPW9, HPWI2 were prepared for 4irst time by reaction of organobisphosphonic acids or their sodium salts with sodium tungstate, tranditional acidulation and diethyl ether extraction. The title compounds were characterized with IR, UV, TGA, DSC, XPS, XRD, polargram,gravimetric analysis and potential titration and so on. The formation of the HPA and their lields were affected by the pill values of the reaction solution and the ratio of the reaction materials as well as the presence of some reducing impurity. Organic substituents of bisphosphonie acids have some influence on the structures and properties of the heteropoly acids. The results indicated: the primary structure of bisaminoalkylphosphOflOtUflgStiC heteropoly acid HPW2, HPW3, HPW4, HPW12 are all Keggin type structure whose P: W ratio is 1:12. The N-contained side chain and the phosphonic acid group -P03H2 participate in the composition of the primary structure of heteropoly anions. That means each nitrogen atom and the nearmost phosphonic acid group -P03H2 altogether are as the core or coordination center of one heteropoly anion. There are two heteropoly anions in each side of the molecule and the -(CH2)- chain between two nitrogen atoms of diamine links the two anions together. The molecule looks like a dumbbell. The primary structure of iminobisalkylphosphonotuflgStiC heteropoly acid HPW1, HPW5, HPW6, IIPW7, HPW9 are vacancy Keggin type structure which P: W ratio is (1:11)2.