Synthesis of mono and diesters using eco-friendly solid acid catalyst – zirconium titanium phosphate

Abstract

Amorphous zirconium titanium phosphate (ZTPA), an advanced inorganic ion exchanger of the class of tetravalent bimetallic acid (TBMA) salt, has been synthesized by sol gel route. ZTPA has been characterized by inductively coupled plasma atomic emission spectrometer (ICP-AES), Thermal analysis, Fourier transform infrared spectrometer (FTIR), and X-ray diffraction (XRD). The acid sites present in ZTPA indicate good potential to be explored as solid acid catalyst. The catalytic characteristics of ZTPA have been evaluated by determining surface area and surface acidity. The catalytic performance of ZTPA as a solid acid catalyst has been explored by studying esterification as a model reaction wherein mono and diesters have been synthesized. Crystalline zirconium titanium phosphate as well as amorphous and crystalline phases of zirconium phosphate and titanium phosphate have also been synthesized, characterized, and their catalytic performance investigated for comparative studies. TBMA salt exhibits enhanced catalytic activity compared to its single salt counterparts and amorphous phases exhibit higher catalytic activity compared to their crystalline phases.     

Ion transport in MF-4SK cation-exchange membranes modified with acid zirconium phosphate

An MF-4SK cation-exchange membrane has been modified to obtain composite materials containing acid zirconium phosphate particles. It is demonstrated by electron microscopy and X-ray diffraction that acid zirconium phosphate in the resulting membrane is in the crystalline state. As compared to the initial MF-4SK membrane, the modified membrane shows a somewhat lower diffusion permeability and a higher ion selectivity.     

Preparation and sorption properties of zirconium phosphate spherical particles

Spherical particles of zirconium phosphate ion-exchanger have been prepared by the conversion of hydrous zirconia prepared by the sol-gel method. Some physicochemical properties, stabilities and sorptions of 1–4-valent cations have been studied and compared with those of amorphous zirconium phosphate powder.     

Comparison of sodium zirconium phosphate and calcium zirconium phosphate structures for the retention of fluoride

Fluoride anion interaction has been explored for the first time to investigate how the structure of sodium zirconium phosphate (NZP) and calcium zirconium phosphate (CZP) can be altered in its presence. Different compositions were made by adding NaF and CaF₂ in CZP and NZP matrices respectively. Fluoride interaction differs with NZP and CZP structure as suggested by F-NMR data. The addition of fluoride to the NZP or CZP structure enables to stabilize the structure at a low temperature of 600–700 °C under microwave conditions.     

Extraction of cations as salts of fatty acids : Analytical and chromatographic separation of beryllium from iron and aluminium

Quantitative extractions of aluminium and ferric ions are carried out in presence of butyric acid. A method has been given for quantitative extraction of beryllium from aluminium and ferric ion in presence of ethylenediaminetetra-acetic acid. Interference has been studied and interference due to phosphate has been avoided by addition of zirconium salt. The method has been applied to thc analysis of beryl.     

Sorption of phosphate ions on iron(III), zirconium(IV), and chromium(III) oxyhydroxides from aqueous electrolyte solutions

The adsorption of phosphate ions from aqueous solutions with an ionic strength of 0.5 on iron(III), zirconium(IV), and chromium(III) oxyhydroxide hydrogels has been studied as influenced by chloride and sulfate ions. Despite the high concentrations of chloride and sulfate ions, they do not inhibit phosphate adsorption on the hydrogels; they only slightly change the isotherm shape. In the range of equilibrium phosphate concentrations equal to 30–50 mmol/l, all isotherms for iron and zirconium oxyhydroxide gels signify the appearance of a second adsorption layer (two-step isotherms). Both steps are satisfactorily fitted by the Langmuir equation. The maximum adsorptions and adsorption constants have been calculated. For chromium oxyhydroxide gels, the intraduction of an electrolyte dramatically decreases the equilibration rate.     

Some considerations on the treatment of the kinetic data of heterogeneous isotope exchange

A direct curve simulation treatment has been worked out for the evaluation of the kinetic curves of heterogeneous isotope exchange. Based on the data obtained by a personal computer some considerations have been made on the transport processes in the fully and half exchanged sodium forms of crystalline zirconium phosphate.     

Determination of uranium in zircon

A routine fluorimetric procedure is described for the determination of trace amounts of uranium in zircon. It employs the direct extraction of uranyl nitrate with ethyl acetate using phosphate as a retainer for zirconium. Submicrogram amounts or uranium are separated in the presence of 100,000 times the amount of zirconium. The modified procedure has been worked out using synthetic mixtures of known composition and zircon. Results of analyses have an accuracy of 97–98% of the contained uranium and a standard deviation of less than 2.5%.     

A comparative study of the catalytic activity of [Cu(NH3)4]2+ sorbed on zirconium phosphate and zirconium phenylphosphonate

Summary The complex cation [Cu(NH₃)₄]²⁺ has been sorbed on to two different supports: zirconium phosphate and zirconium phenylphosphonate, and the products characterized by elemental analysis, FTIR, e.s.r., reflectance spectra, t.g.a. and surface area measurements (BET method). The catalytic activity of these materials has been studied through the disproportionation of H₂O₂. The kinetic data and calculated energy of activation show that the complex cation, supported on zirconium phenylphosphonate, exhibits enhanced catalytic activity.Author to whom all correspondence should be directed.     

Synthesis of ordered mesoporous zirconium phosphate films by spin coating and vapor treatments

Ordered mesoporous zirconium phosphate films were prepared on a silicon substrate by spin coating using a mixture of zirconium isopropoxide, triethyl phosphate, Pluronic P123 triblock copolymer, nitric acid, ethanol, and water. The spin-on film was consecutively treated with vapors of phosphoric acid and ammonia. The post-vapor treatments effectively enhanced the thermal stability of an ordered mesostructure when heated to 500 degrees C. XRD and TEM analyses show that the calcined zirconium phosphate film has a hexagonal structure with straight channels parallel to the film surface. The zirconium phosphate film exhibited high proton conductivity of 0.02 S/cm parallel to the film surface at 80% RH and 25 degrees C.     

Élaboration de ciments apatitiques composites pour la rétention du césium et de l’iode

A composite apatitic cement made of hydroxyapatite loaded with β-tricalcic phosphate, zirconium phosphate and activated carbon has been elaborated and its ability to block cesium and iodine tested. It could be used as a buffer material in order to prevent the rapid release of soluble fission products (cesium and iodine) in aqueous solutions leaching the spent fuel, in the case of direct disposal of spent fuel.     

Modification and intercalation of layered zirconium phosphates: a solid‐state NMR monitoring

Several layered zirconium phosphates treated with Zr(IV) ions, modified by monomethoxy‐polyethyleneglycol‐monophosphate and intercalated with doxorubicin hydrochloride have been studied by solid‐state MAS NMR techniques. The organic components of the phosphates have been characterized by the ¹³C{¹H} CP MAS NMR spectra compared with those of initial compounds. The multinuclear NMR monitoring has provided to establish structure and covalent attachment of organic/inorganic moieties to the surface and interlayer spaces of the phosphates. The MAS NMR experiments including kinetics of proton‐phosphorus cross polarization have resulted in an unusual structure of zirconium phosphate 6 combining decoration of the phosphate surface by polymer units and their partial intercalation into the interlayer space. Copyright © 2016 John Wiley & Sons, Ltd.     

Adsorption and radiochemical separation of caesium(I) using zirconium phosphate ion exchanger

A rapid and selective method has been developed for the separation of caesium(I) from other metal ions by adsorbing it on zirconium phosphate ion exchanger. Various parameters involved in the quantitative adsorption of caesium(I) on the ion exchanger have been evaluated employing¹³⁷Cs as a tracer.     

Complexometric determination of magnesium in nodular cast iron and alloyed cast iron roll samples

A complexometric method for the determination of magnesium in nodular cast iron, alloyed cast iron and roll samples has been developed. The bulk of the iron is removed by ether extraction and the phosphate as zirconium phosphate. The other elements are removed by extraction with dithiocarbamate into chloroform. Magnesium is then titrated with EDTA at pH 10, with Eriochrome Black T as indicator. Calcium interferes, but is very rarely present in such cast iron samples.     

DTA,ETA, and TG investigations of Zirconium phosphates of different crystallinity

Interpretation of all thermal effects which occur on heating zirconium phosphates is possible when simultaneous DTA, ETA, and TG is applied. A rapid transition of poorly crystalline zirconium phosphate into normal cubic modification at high temperatures is clearly shown by DTA when amorphous zirconium phosphate is used. In contrast, because of the more rigid crystal lattice, this reaction is only visible in ETA when crystalline preparations are heated.Especially after exchange of protons by cations, some amorphous zirconium phosphates exhibit a second exotherm in DTA. This reaction is believed to depend on growing up of partially crystalline structures.     

Inorganic membranes based on zirconium phosphate for fuel cells

In this paper we report on zirconium phosphate based inorganic membrane preparation and electrochemical characterization. The zirconium oxide microporous membranes were impregnated with colloidal particles of zirconium phosphate and were designed for application in direct methanol fuel cells. Scanning electron microscopy, thermogravimetry and impedance spectroscopy was used for membrane characterization.     

The special effect of fluoride on the chromatography of acidic analytes on polybutadiene-coated zirconia

Summary The special effect of fluoride as a Lewis base additive in suppressing the ligand-exchange interactions for acidic analytes on polybutadiene-coated zirconia (PBD-ZrO₂) has been investigated. We found that fluoride is more effective than phosphate in improving the separation efficiency for strong acids. The improvement is attributed to that fluoride has a smaller size and a more flexible coordination chemistry towards zirconium centers than phosphate; consequently, fluoride can more effectively improve the kinetics of the ligand-exchange processes for strongly acidic analytes. We demonstrated that using a small amount of fluoride in combination with a larger quantity of phosphate is a practical way to improve the separation efficiency and resolution for acidic analytes. Some example separations are presented.     

Effect of phosphate ion on filtration characteristics of solids generated in simulated high level liquid waste

The effect of phosphate ion on the filtration characteristics of solids generated in a high level liquid waste was experimentally examined. Addition of phosphate ion into the simulated HLLW induced the formation of phosphate such as zirconium phosphate and phosphomolybdic acid. The filtration rate of zirconium phosphate abruptly dropped in the midst of filtration because of a gel-cake formation on the filter surface. The denitration of the simulated HLLW contained zirconium phosphate improved the filterability of this gelatinous solid. The filtration rates of denitrated HLLW decreased with increase of the phosphate ion concentration, since the solids formed by denitration had irregular particle size and configuration in the simulated HLLW with phosphate ion. To increase the filtration rate of denitrated HLLW, a solid suspension filtration tester was designed. The solid-suspension accelerated the filtration rate only in the simulated HLLW with more than 1500 ppm phosphate ion concentration. Under this condition, the simple agitation can easily suspend the constituent solids of filter cake in the solution and a much higher filtration rate can be obtained because the filter cake is continuously swept from the filter surface by rotation of propellers.     

Use of zirconium phosphate as ion exchanger in some parent-daughter radioisotope separations

Zirconium phosphate as ion exchanger suitable for column operation has been prepared by mixing hot metaphosphoric acid solution with a solution of zirconium oxychloride when the white insoluble phosphate separated out which was dried and purified. The ratio of zirconium: phosphate was found to be 1:2. Separation of parent-daughter systems like¹¹⁵Cd-^115mIn,¹⁴⁴Ce-¹⁴⁴Pr and²¹⁰Pb-²¹⁰Bi were carried out with this exchanger. γ-ray spectrum of the separated^115mIn and the β-decay curve of¹⁴⁴Pr and²¹⁰Bi showed that all the daughter activities are radiochemically pure. The separation process in each case takes less than half an hour and the yield is quantitative.     

Radiochemical separation by inorganic ion exchanger and determination of cesium in complex matrices by thermal neutron activation analysis

A rapid and selective method has been developed for radiochemical separation, and determination of Cs in complex matrices by thermal neutron activation analysis. Batch adsorption of ¹³⁴Cs was carried out on zirconium phosphate ion exchanger. A large number of samples of the ore have been analysed for their Cs content and the results are discussed.