http://nopr.niscair.res.in/handle/123456789/958 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/1070 Title: Synthesis of parabens using montmorillonite K10 clay as catalyst: A green protocol <br/> <br/>Authors: Hazarika, Mridul Kumar; Parajuli, Raghab; Phukan, Prodeep <br/> <br/>Abstract: Synthesis of three parabens is achieved using montmorillonite K10 clay as heterogeneous catalyst. Methyl, ethyl, and propyl parabens were synthesized by esterification of 4-hydroxy benzoic acid with the corresponding alcohol. The catalyst can easily be separated from the reaction mixture and reused successfully with-out affecting the catalytic activity. <br/> <br/>Page(s): 104-106 Fri, 29 Dec 2006 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1069 Title: Study on thermodynamic properties of solvent extraction for 2-chloro-4, 6-dinitro-resorcinol <br/> <br/>Authors: Ruixin, Shi; Yudong, Huang <br/> <br/>Abstract: Thermodynamic properties of solvent extraction of 2-chloro-4,6-dinitro-resorcinol from aqueous phase were investigated. With ethyl acetate as the extractant and an organic solvent, such as benzene, toluene, cyclohexane and n-heptane as the diluent, the composition of the extracted species was determined by the method of slope analysis and the results show that the composi-tion relates to the diluent. It is also found that the distribution coefficient of 2-chloro-4,6-dinitro-resorcinol in the organic phase increases with the increase of the dielectric constant of the diluent. It is confirmed that the extraction of 2-chloro-4,6-dinitro-resorcinol is an exothermic process and the apparent thermal effect, ΔH , is -10.088 kJmol⁻¹. <br/> <br/>Page(s): 100-103 Fri, 29 Dec 2006 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1068 Title: Quantitative complexometric determination of palladium(II) in its synthetic alloys, complexes and catalysts using 2-mercaptopropionic acid as a selective masking agent <br/> <br/>Authors: Karthikeyan, J; Parameshwara, P; Shetty, A Nityananda; Shetty, Prakash <br/> <br/>Abstract: A simple, rapid and accurate complexometric method for the determination of palladium(II) is proposed, based on the selective masking property of 2-mercaptopropionic acid towards palladium(II). In the presence of diverse metal ions, palladium(II) is complexed with excess of EDTA and the surplus EDTA is backtitrated with standard zinc sulphate solution at pH 5-5.5 (acetic acid-sodium acetate buffer) using xylenol orange as indicator. An excess of a 0.5% aqueous solution of 2-MPA is then added to displace EDTA from Pd(II)-EDTA complex. The released EDTA is titrated with the same standard zinc sulphate solution as before. Reproducible and accurate results are obtained in the concentration range 0.5-17.80 mg of palladium with relative error of ± 0.50% and coefficient of variation not exceeding ± 0.33%. The effects of diverse ions are studied. The method is used for the determination of palladium in its complexes, catalysts and synthetic alloy mixtures. <br/> <br/>Page(s): 96-99 Fri, 29 Dec 2006 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1067 Title: Validation of theoretical model for ion exchange chromatographic separation of boron isotopes <br/> <br/>Authors: Sujish, D; Sharma, B K; Anand Babu, C <br/> <br/>Abstract: Ion exchange chromatography and distillation route have been used for separation of boron isotopes. Of these, ion exchange chromatography is more economical and industrially viable technique. Mathematical model for isotope separation using ion exchange chromatography is reported in literature and was used to predict the enrichment profile for boron. Experiments were conducted using six columns of 50 mm diameter and boron enrichment profile measured. The prediction of the model was found to be reasonably matching with the experimental measurements. <br/> <br/>Page(s): 92-95 Fri, 29 Dec 2006 22:58:59 GMT