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The ion exchange of α-zirconium phosphate (ZrP) nanoparticles, highly crystalline zirconium phosphates prepared by the hydrothermal method, and epoxide functionalized zirconium phosphates were investigated. A series of exchange reactions involving both the surface and interlayer were used to determine exchange capacities for each environment and investigate the relationship between the interlayer and surface phosphates of ZrP. The resulting relationship was used to develop a new methodology to determine the average particle thickness within a sample of ZrP. Upon functionalization, the exchange capacities of derivatives prepared by surface functionalization (SF) and full functionalization (FF) were compared to the pristine ZrP, and an additional method was developed to determine the degree of functionalization in each sample. [ABSTRACT FROM AUTHOR]

Tetravalent metal phosphates (M=Zr, Ti, and Sn) were prepared and characterized by XRD, surface properties, and TG-DTA. The cation exchange and sorption behavior of these metal phosphates toward transition metal ions such as Cu2+, Co2+, and Ni2+ have been studied comparatively as a function of temperature and concentration. The adsorption process was found to increases with increase in temperature and concentration. The selectivity order for α-titanium and α-tin phosphates is Cu2+>Co2+>Ni2+, whereas for α-zirconium phosphate it is Cu2+>Ni2+>Co2+. The ion exchange capacity of α-titanium phosphate is greater than those of other phosphates, which is explained on the basis of the surface behavior, disorderness of the system, degree of hydrolysis of incoming guest adsorbate metal ions, and structural steric hindrance of the exchangers during adsorption and sorption. The distribution coefficient, Gibbs free energy, enthalpy, and entropy values indicate that the ion-exchange processes are spontaneous. [Copyright &y& Elsevier]

The selectivity of γ-crystalline zirconium phosphate, amorphous zirconium phenylphosphonate, amorphous zirconium molybdenum phosphate and microporous crystalline aluminium methylphosphonate was evaluated in oxidation reactions of phenol. The different selectivities are correlated to the properties and structure of each compound. [ABSTRACT FROM AUTHOR]

Tetravalent metal phosphates form highly insoluble inorganic polymers and act as catalysts in some oxidative reactions. In the present work, α-amorphous zirconium, tin, titanium, zirconium tungstate (acidic and basic form), crystalline vanadyl, fibrous crystalline cerium and pellicular zirconium phosphates, were prepared and evaluated as catalysts, for the hydroxylation of phenol and 2-naphthol by hydrogen peroxide, in acetic acid. Oxidation of phenol yielded hydroquinone, catechol, cis,cis-muconic and cis,trans-muconic acids, depending on the catalyst. All oxidations of 2-naphthol produced 4-(2-hydroxy-1-naphthyl)-1,2-naphthoquinone but reaction with crystalline vanadyl phosphate also resulted in the formation of 1,1′-bi(2-naphthol). [Copyright &y& Elsevier]

Amorphous zirconium, tin, titanium, vanadyl, cerium and scandium/zirconium phosphates have been evaluated in relation to their effects on the catalysed formation of peroxyacetic acid (PAA) from hydrogen peroxide and acetic acid. The rate of formation of PAA remained almost the same whether the phosphates were present or absent, for most of the phosphates. However, by exchanging the acidic hydroxyl centres in ZrPA with scandium(III), it was found that the resulting solid, ScZrPA, strongly accelerated the formation of PAA, even more so than the scandium(III) ions in homogeneous solution. [Copyright &y& Elsevier]