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Determination of Organic Acids in Process Solutions

Description: Abstract: "A method has been established for the estimation of volatile organic acids in aqueous process solutions containing UNH, nitric acid, ANN, sodium dichromate and small amounts of hexone. The practice is to distill a 400 ul or 500 ul sample in the presence of an excess of phosphoric acid and ferrous sulfate under a high vacuum; a special apparatus utilizing a receiver cooled with a dry ice-isopropanol mixture is employed. The distillate is taken up in isopropanol and then titrated potentiometrically with standard potassium hydroxide solution. Since nitric acid and organic acids are present, two end points are observed. The potassium hydroxide added between these end points is equivalent to the organic acids. In the titration, CO2 from the atmosphere or in the potassium hydroxide is a source of error. The former was avoided and correction was made for the latter."
Date: June 29, 1949
Creator: Brouns, R. J. & Pollock, C. W.
Partner: UNT Libraries Government Documents Department

Infrared Studies of Anions of Barbituric Acids

Description: As long ago as 1881, it was realized that a functional group of atoms in a molecule would cause an absorption band to appear at a particular frequency in the infrared spectrum of the molecule. In more recent years, the concept of characteristic group frequencies has become firmly established and has resulted in the present widespread use of infrared spectroscopy. There appear to have been relatively few studies of infrared absorption of organic acids as compared with their salts.
Date: August 1960
Creator: Barnhart, Richard Lee
Partner: UNT Libraries

Zinc distribution and speciation in Arabidopsis halleri x Arabidops is lyrata progenies presenting various zinc accumulation capacities

Description: - The purpose of this study was to investigate the relationship between the chemical form and localization of zinc (Zn) in plant leaves and their Zn accumulationcapacity. - An interspecific cross between Arabidopsis halleri sp. halleri and Arabidopsis lyrata sp. petrea segregating for Zn accumulation was used. Zinc (Zn) speciation and Zn distribution in the leaves of the parent plants and of selected F1 and F2 progenies were investigated by spectroscopic and microscopic techniques and chemical analyses. - A correlation was observed between the proportion of Zn being in octahedral coordination complexed to organic acids and free in solution (Zn?OAs + Znaq) and Zn content in the leaves. This pool varied between 40percent and 80percent of total leaf Zn depending on the plant studied. Elemental mapping of the leaves revealed different Zn partitioning between the veins and the leaf tissue. The vein : tissue fluorescence ratio was negatively correlated with Zn accumulation. - The higher proportion of Zn?OAs + Znaq and the depletion of the veins in the stronger accumulators are attributed to a higher xylem unloading and vacuolar sequestration in the leaf cells. Elemental distributions in the trichomes were also investigated, and results support the role of carboxyl and⁄ or hydroxyl groups as major Zn ligands in these cells.
Date: April 8, 2010
Creator: Sarret, Geraldine; Willems, Glenda; Isaure, Marie-Pierre; Marcus, Matthew A.; Fakra, Sirine C.; Frerot, Helene et al.
Partner: UNT Libraries Government Documents Department

Detector Comparison for Simultaneous Determination of Organic Acids and Inorganic Anions

Description: The research reported here is a study of detector systems to determine those most suited for simultaneous organic acid, inorganic anion determination. Comparisons are made on the basis of detection limits and sensitivities for conductivity, UV/Vis, photoconductivity, and derivative conductivity detection systems. The investigation was made using a constant chromatographic system with the only variable component being the detector system. Eluant optimization conditions for each detector are reported along with tables reporting detection limits and sensitivities for each detector system. Various chromatograms are also shown to provide a visual comparison between detector results.
Date: August 1988
Creator: Pannell, Daniel K. (Daniel Kirk)
Partner: UNT Libraries

Solubilities of significant compounds in HLW tank supernate solutions - FY 1996 progress report

Description: The solubilities of two sodium salts of organic acids that are thought to exist in high-level waste at the Hanford Site were measured in tank supernate simulant solutions during FY1996 This solubility information will be used to determine if these organic salts could exist in solid phases (saltcake or sludges) in the waste where they might react violently with the nitrate or nitrite salts present in the tanks. Solubilities of sodium butyrate and trisodium N-(2-hydroxyethyl)ethylenediaminetriacetate were measured in simulated waste supernate solutions at 25 {degrees}C, 30 {degrees}C, 40 {degrees}C, and 50 {degrees}C. The organic compounds were selected because they are expected to exist in relatively high concentrations in the tanks. Two types of tank supernate simulants were used - a 4.O M sodium nitrate - 0.97 M sodium nitrite solution with sodium hydroxide concentrations ranging from O.00003 M to 2.O M and a 2.O M sodium nitrite solution saturated with crystalline sodium nitrate with sodium hydroxide concentrations ranging from 0.1 M to 2. 0 M. The solubilities of sodium butyrate and trisodium N-(2-hydroxyethyl)ethylene- diaminetriacetate in both types of HLW tank supernate solutions were high over the temperature and sodium hydroxide concentration ranges expected in the tanks. The solubilities of these compounds are similar (in terms of total organic carbon) to sodium glycolate, succinate, caproate, dibutylphosphate, citrate, formate, ethylenediaminetetraacetate, and nitrilotriacetate which were measured previously. High solubilities will prevent solid sodium salts of these organic acids from precipitating from tank supernate solutions. The total organic carbon concentrations (TOC) of actual tank supernates are generaly much lower than the TOC ranges for the simulated supernate solutions saturated (at the solubility limit) with the organic salts. This is true even if all the dissolved carbon in a given tank supernate is due to only one of these eight soluble compounds (an unlikely situation). ...
Date: September 30, 1996
Creator: Barney, G.S.
Partner: UNT Libraries Government Documents Department

Theoretical Structures of Triflic Acid-Water Clusters and the Molecular Mechanism of Proton Dissociation

Description: Structural and energetic information required for recently proposed quasi-chemical theories of solution chemistry have been obtained for clusters of water with triflic acid, CF{sub 3}SO{sub 3}H(H{sub 2}O){sub n} for n=1-6. Quantum mechanical calculations on the clusters indicate that the acid proton does not dissociate with n=1 or 2 hydrating water molecules, but does dissociate for n>=3 water molecule partners. The computed minimum energy structures indicate that both ''Eigen'' (H{sub 9}O{sub 4}{sup +}) (n=3,4,6) and ''Zundel'' (H{sub 5}O{sub 2}{sup +}) (n=5) structures are likely to play a role in the molecular mechanism of acid dissociation in Nafion{reg_sign}.
Date: November 1, 1998
Creator: Paddison, S.J.; Pratt, L.R. & Zawodzinski, T.A.
Partner: UNT Libraries Government Documents Department

Bioconversion of Cheese Waste (Whey)

Description: The US dairy industry produces 67 billion pounds of cheese whey annually. A waste by-product of cheese production, whey consists of water, milk sugar (lactose), casein (protein), and salts amounting to about 7% total solids. Ultrafiltration is used to concentrate cheese whey into a protein-rich foodstuff; however, it too produces a waste stream, known as ''whey permeate,'' (rejected water, lactose, and salts from the membrane). Whey permeate contains about 4.5% lactose and requires treatment to reduce the high BOD (biological oxygen demand) before disposal. Ab Initio, a small business with strong chemistry and dairy processing background, desired help in developing methods for bioconversion of whey permeate lactose into lactic acid. Lactic acid is an organic acid primarily used as an acidulant in the food industry. More recently it has been used to produce polylactic acid, a biodegradable polymer and as a new method to treat meat carcasses to combat E. coli bacteria. Conversion of whey permeate to lactic acid is environmentally sound because it produces a valued product from an otherwise waste stream. FM&T has expertise in bioconversion processes and analytical techniques necessary to characterize biomass functions. The necessary engineering and analytical services for pilot biomass monitoring, process development, and purification of crude lactic acid were available at this facility.
Date: March 11, 1998
Creator: Bohnert, G.W.
Partner: UNT Libraries Government Documents Department

Toxicology of Aurin Tricarboxylic Acid and Its Antidotal Effectiveness Against Beryllium

Description: Monkeys and dogs were used in a series of studies designed to assess the ability of aurin tricarboxylic acid (ATA) to provide protection against acute beryllium poisoning. The acute LD/sub 50/ of ATA was found to be 344 mg/kg for monkeys and 164 mg/kg for dogs. Neither species exhibited significant hematological changes when given weekly ATA doses of 25 mg/kg over an 8-month period. The lethal intravenous dose of beryllium sulfate was 0.6 mg/kg for both dogs and monkeys, but the value increased to between 1 and 3 mg/kg when given by intratracheal injection. Acute toxic effects were not observed by either intravenous or intratracheal doses of suspensions of beryllium oxide. Treatment with ATA appeared to have therapeutic value in monkeys exposed to beryllium, but no significant response was observed in dogs. (auth)
Date: December 1, 1961
Creator: King, M. E.
Partner: UNT Libraries Government Documents Department

Bio-/Photo-Chemical Separation and Recovery of Uranium

Description: Citric acid forms bidentate, tridentate, binuclear or polynuclear species with transition metals and actinides. Biodegradation of metal citrate complexes is influenced by the type of complex formed with metal ions. While bidentate complexes are readily biodegraded, tridentate, binuclear and polynuclear species are recalcitrant. Likewise certain transition metals and actinides are photochemically active in the presence of organic acids. Although the uranyl citrate complex is not biodegraded, in the presence of visible light it undergoes photochemical oxidation/reduction reactions which result in the precipitation of uranium as UO{sub 3} {center_dot} H{sub 2}O. Consequently, we developed a process where uranium is extracted from contaminated soils and wastes by citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, whereas uranyl citrate which is recalcitrant remains in solution. Photochemical degradation of the uranium citrate complex resulted in the precipitation of uranium. Thus the toxic metals and uranium in mixed waste are recovered in separate fractions for recycling or for disposal. The use of naturally-occurring compounds and the combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in cost.
Date: March 12, 2008
Creator: Francis,A.J. & Dodge, C.J.
Partner: UNT Libraries Government Documents Department

The Effect of Chronic Gamma Irradiation on Apical Dominance of Trees

Description: Cherry and apple trees subjected to low doses of gamma irradiation (average of 16 and 34 r/day) for 10 years produced atypical branch development and reversal of dominance which could be attributed to the decrease or inactivation of auxin resulting from the irradiation. (auth)
Date: October 31, 1964
Creator: Sax, K. & Schairer, L. A.
Partner: UNT Libraries Government Documents Department


Description: Batch processes on a scale of 250 to 300 g of uranium were developed for the production of uranyl oxinate (8quinolinate) and uranyl malonate. Both compounds are insoluble in water and were found to be suitably soluble in pitch. Uranyl oxinate was prepared by the reaction of an aqueous uranyl nitrate solution with an acetic acid solution of oxine (8-quinolirol) at about 80 deg C. Complete precipitation was accomplished by the addition of ammonium hydroxide. Yields of better than 99.5% were obtained. Uranyl malonate was prepared by the reaction of aqueous solutions of sodium malonate and uranyl nitrate at about 80 deg C in 97 to 98% yield. Uranyl 2-ethylhexanoate was prepared by a transesterification reaction from uranyl acetate and 2-ethylhexanoic acid. Yields of 90% were obtained but the process was quite laborious ard time consuming. A metathesis method of preparation was not successful. (auth)
Date: May 1, 1959
Creator: Baxman, H.R.; Jackson, D.D.; Williams, D.L. & Bard, R.J.
Partner: UNT Libraries Government Documents Department