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Anion Exchange Resin (anion + exchange_resin)
Selected AbstractsPolymer-Supported Bisacetoxybromate(I) Anion ,-An Efficient Co-Oxidant in the TEMPO-Mediated Oxidation of Primary and Secondary AlcoholsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2003Marco Brünjes Abstract A polymer-bound reagent for the efficient oxidation of primary alcohols to aldehydes and secondary alcohols to ketones in the presence of a catalytic amount of 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) is described. The oxidation process is particular mild and allows one to prepare aldehydes with ,-chirality without racemization. This also includes the synthesis of ,-aminoaldehydes. In most cases, work-up of this heavy metal-free oxidation is achieved by simple filtration followed by removal of the solvent. Insight into the role of the bromate(I) anion in the oxidation process was gained from the TEMPO-mediated oxidation of benzaldehyde in the presence of the hypochlorite anion loaded on an anion exchange resin. [source] Synthesis of a cellulose-grafted polymeric support and its application in the reductions of some carbonyl compoundsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Poonam K. Dhiman Abstract The reduction of carbonyl compounds by borohydride supported on a cellulose,anion exchange resin is known. The synthesis of a graft copolymer of cellulose and poly(4-vinyl pyridine) [CellO- g -poly(4-VP)] has been carried out with ceric ions as a redox initiator. A postgrafting treatment of CellO- g -poly(4-VP) with sodium borohydride has produced CellO- g -poly(4-VP) borane, a polymer-supported reducing agent. Optimum conditions pertaining to the maximum percentage of grafting have been evaluated as a function of the concentrations of the initiator, monomer, and nitric acid, amount of water, time, and temperature. The maximum percentage of grafting (585%) has been obtained with 0.927 mol/L of 4-vinyl pyridine and 0.018 mol/L of ceric ammonium nitrate in 120 min at 45°C. The polymeric support, CellO- g -poly(4-VP) borane, has been used for reduction reactions of different carbonyl compounds such as benzaldehyde, cyclohexanone, crotonaldehyde, acetone, and furfural. The graft copolymer has been characterized with IR and thermogravimetric analysis. The grafted cellulose has been found to be thermally stable. The reduced products have been characterized with IR and NMR spectral methods. The reagent has been reused for the reduction of a fresh carbonyl compound, and it has been observed that the polymeric reagent reduces the compounds successfully but with a little lower product yield. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] ORGANIC ACIDS PROFILE IN TOMATO JUICE BY HPLC WITH UV DETECTIONJOURNAL OF FOOD QUALITY, Issue 1 2007OMBRETTA MARCONI ABSTRACT A simple method was developed to determine 10 organic acids simultaneously in tomato products using reverse-phase high performance liquid chromatography (HPLC) column with the diode array detector set at 210 nm. After centrifugation and filtration, the samples were passed through to an anion exchange resin and the organic acids were released using 0.1 N HCl. The chromatographic separation was achieved with isocratic analysis in a 20-min run. The method was reliable and sensitive. The coefficient of determination of the standard calibration curve is 0.9925 , r2 , 0.9999 and the limit of detection ranged from 0.08 to 6.00 mg/kg for trans -aconitic acid and acetic acid, respectively. The limit of quantification ranged from 0.19 to 15.18 mg/kg for trans-aconitic and acetic acid, respectively. To establish the efficiency of the anion resin the procedure was applied to a standard solution of a mixture of organic acids. The organic acids recovery ranged from 87.0% ± 1.9 for citramalic acid to 109.9% ± 5.2 for fumaric acid. [source] Impurities in a morphine sulfate drug product identified as 5-(hydroxymethyl)-2-furfural, 10-hydroxymorphine and 10-oxomorphineJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2003Seán S. Kelly Abstract Stability testing of morphine sulfate formulated with nonpareil sugar seeds (consisting of sucrose and starch) and fumaric acid revealed the formation of the three impurities 5-(hydroxymethyl)-2-furfural, 10-hydroxymorphine and 10-oxomorphine. 5-(Hydroxymethyl)-2-furfural was isolated via semipreparative HPLC utilizing volatile mobile phase constituents and was identified by analysis of its HRMS and NMR spectra. 10-Hydroxymorphine and 10-oxomorphine were obtained via semipreparative HPLC and subsequent removal of ion-pair reagents using an anion exchange resin, or by solid phase extraction, and identified by spectroscopic analysis followed by comparison with authentic materials. 5-(Hydroxymethyl)-2-furfural is a degradation product of hexose sugars, and its formation in the presence of morphine sulfate formulated with fumaric acid suggests that caution should be exercised when including nonpareil seeds in formulations that contain acidic drug salts and/or acid excipients. The preliminary results of tests on the interaction of acidic salts of some other drugs with nonpareil seeds are presented. © 2003 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:485,493, 2003 [source] Detection of adulterations in processed coffee with cereals and coffee husks using capillary zone electrophoresisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 20 2009Thiago Nogueira Abstract The proposed method for the identification of adulteration was based on the controlled acid hydrolysis of xylan and starch present in some vegetable adulterants, followed by the analysis of the resulting xylose and glucose, which are the monosaccharides that compose, respectively, the two polysaccharides. The acid hydrolysis with HCl increases the ionic strength of the sample, which impairs the electrophoretic separation. Thus, a neutralization step based on anion exchange resin was necessary. The best separations were obtained in NaOH 80 mmol/L, CTAB 0.5 mmol/L, and methanol 30% v/v. Because of the high value of pH, monosaccharides are separated as anionic species in such running electrolyte. The LOQ for both monosaccharides was 0.2 g for 100 g of dry matter, which conforms to the tolerable limits. [source] Liquid phase mineralization of gel-type anion exchange resin by a hybrid process of Fenton dissolution followed by sonication and wet air oxidationASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009T. L. Gunale Abstract A hybrid process of Fenton dissolution followed by sonication and wet air oxidation (WAO), has been demonstrated to mineralize strongly basic anion exchange resin (gel type). The solid anion exchange resin beads could be dissolved in water by Fenton process wherein the copper-catalyzed hydrogen peroxide (H2O2) reaction makes the resin hydrophilic by the disintegration of polymer matrix. Sonication of the dissolved resin thus obtained made the waste stream more amenable to WAO. Parameters for Fenton dissolution and sonication were studied to aid effective mineralization by WAO. The kinetic studies of WAO were performed using copper sulfate (CuSO4) as the homogeneous catalyst, in the temperature range of 483,523 K. It is thus possible to address the disposal of solid ion exchange resin by the hybrid process, described here. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Fractionation of ,-Lactoglobulin from whey by mixed matrix membrane ion exchange chromatographyBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2009Syed M. Saufi Abstract Mixed matrix membranes (MMMs), which incorporate adsorptive particles during membrane casting, can be prepared simply and have performances that are competitive with other membrane chromatography materials. The application of MMM chromatography for fractionation of ,-Lactoglobulin from bovine whey is described in this article. MMM chromatography was prepared using ethylene vinyl alcohol polymer and lewatit anion exchange resin to form a flat sheet membrane. The membrane was characterized in terms of structure and its static and dynamic binding capacities were measured. The optimum binding for ,-Lactoglobulin was found to be at pH 6.0 using 20 mM sodium phosphate buffer. The MMM had a static binding capacity of 120 mg/g membrane (36 mg/mL membrane) and 90 mg/g membrane (27 mg/mL membrane) for ,-Lactoglobulin and ,-Lactalbumin, respectively. In batch fractionation of whey, the MMM showed selective binding towards ,-Lactoglobulin compared to other proteins. The dynamic binding capacity of ,-Lactoglobulin in whey solution was about 80 mg/g membrane (24 mg ,-Lac/mL of MMM), which is promising for whey fractionation using this technology. This is the first reported application of MMM chromatography to a dairy feed stream. Biotechnol. Bioeng. 2009;103: 138,147. © 2008 Wiley Periodicals, Inc. [source] | ||||||||||