Showing papers on "Oxalic acid published in 1972"
TL;DR: Values of oxalic acid in 0.5 ml of urine are generally higher than have been obtained previously by chemical methods and possible reasons for this difference are discussed.
424 citations
TL;DR: The short-term effects of different intakes of calcium and oxalic acid on the urinary excretion of these substances was studied in eight normal men and eight men with a history of calcium-containing renal stones and there was a statistically significant fall in the calcium oxalate activity product in both the patients and normal subjects.
Abstract: 1. The short-term effects of different intakes of calcium and oxalic acid on the urinary excretion of these substances was studied in eight normal men and eight men with a history of calcium-containing renal stones. 2. The effect of dietary oxalate on urine oxalate depended partly upon the calcium intake. Thus, on a normal calcium intake an increase in oxalate intake caused an increase in oxalate excretion that corresponded to 3·6% of the additional dietary oxalate; on a low calcium diet, however, the increase corresponded to 8·1%. 3. A decrease in daily calcium intake from 1000 to 250 mg caused a fall in calcium excretion averaging 150 mg/day in the patients and 60 mg/day in the controls but this was accompanied by average rises of 10 and 7 mg/day respectively in oxalate excretion, with the result that the calcium oxalate activity products remained almost unchanged. 4. A decrease in oxalate as well as calcium intake resulted in a fall in calcium excretion that was not accompanied by a rise in oxalate excretion, and there was a statistically significant fall in the calcium oxalate activity product in both the patients and normal subjects.
131 citations
57 citations
55 citations
TL;DR: Pectic substances have been extracted from plant material by homogenisation with a solution of ammonium oxalate and oxalic acid and subsequently hydrolysed with polygalacturonase and the galacturonic acid produced was determined by a modified carbazole reaction.
Abstract: Pectic substances have been extracted from plant material (a pasture legume, Stylosanthes humilis) by homogenisation with a solution of ammonium oxalate and oxalic acid and subsequently hydrolysed with polygalacturonase The galacturonic acid produced was determined by a modified carbazole reaction The enzymic hydrolysis step may be omitted by relying on the acid in the carbazole reaction partially to hydrolyse the pectic substances, but in doing so the sensitivity of the method is reduced sevenfold Attempts to carry out the hydrolysis with sulphuric acid before the carbazole reaction gave incomplete hydrolysis and probably decarboxylation Attempts to extract the pectic substances with alkali gave low values, probably because of incomplete extraction
44 citations
TL;DR: An automated enzymic method is described for the determination of microgram amounts of oxalic acid, which ranged from 80 to 140 µg per 100 ml in normal human serum ultrafiltrates and similar values were observed for horse serum.
Abstract: An automated enzymic method is described for the determination of microgram amounts of oxalic acid. The acid is decarboxylated by a specific enzyme, oxalate decarboxylase (E.C.4.1.1.2), and the carbon dioxide evolved is measured colorimetrically in a modified Technicon AutoAnalyzer. The minimum detectable concentration of oxalic acid was about 5 µg per 100 ml. For serum it was necessary to remove protein first by ultrafiltration as it interfered with the recorder base-line readings. Phosphate and sulphate ions inhibited enzymic activity, which was allowed for by adding appropriate concentrations of these ions to the standard oxalate solutions used for calibration. The concentration of oxalic acid in normal human serum ultrafiltrates ranged from 80 to 140 µg per 100 ml (mean 118 µg per 100 ml). Similar values were observed for horse serum. The recovery of microgram amounts of oxalic acid added to serum averaged 110 per cent. The coefficient of variation of replicated determinations of oxalic acid was ±2 per cent. for aqueous solutions and ±5 per cent. for serum ultrafiltrates.
42 citations
38 citations
TL;DR: The potential and concentration dependence of oxalic acid adsorption has been investigated on platinized Pt electrodes in 1 M HClO 4 supporting electrolyte by a tracer method as discussed by the authors.
34 citations
Patent•
18 Aug 1972TL;DR: In this paper, the cathodic reduction of oxalic acid to glyoxylic acid production of hydrogen is reduced when the catholyte contains oxalric acid and 0.001 percent - 1 percent of an adjuvant which is a tertiary amine or quaternary ammonium derivative having more than 11 carbon atoms and the nitrogen of which is not part of an unsaturated heterocyclic ring, or a heterocycyclic tertiary ammonium or a QAM derivative thereof, the unsaturated ring being unsaturated, containing a nitrogen atom and at
Abstract: In the cathodic reduction of oxalic acid to glyoxylic acid production of hydrogen is reduced when the catholyte contains oxalic acid and 0.001 percent - 1 percent of an adjuvant which is a tertiary amine or quaternary ammonium derivative having more than 11 carbon atoms and, the nitrogen of which is not part of an unsaturated heterocyclic ring, or a heterocyclic tertiary amine or quaternary ammonium derivative thereof, the heterocyclic ring being unsaturated, containing a nitrogen atom and at least five carbon atoms.
34 citations
TL;DR: The crystal structure of urea oxalic acid, 2[CO(NH2)2],(COOH)2 has been determined using three-dimensional X-ray data, collected on an automatic diffractometer as mentioned in this paper.
Abstract: The crystal structure of urea oxalic acid, 2[CO(NH2)2].(COOH)2 has been determined using three-dimensional X-ray data, collected on an automatic diffractometer. The space group is P21/c. The lattice constants are: a = 5.058 (3), b = 12.400 (3), c = 6.964 (2) A, fl= 98"13 (7) °. The number of molecules in the unit cell is two. The structure consists of layers of urea and oxalic acid molecules held together by hydrogen bonds. The positions of all hydrogen atoms have been found. The compound is not a uronium salt.
30 citations
TL;DR: The calcium content is determined by comparison with standards by atomic absorption, and by calculation the results are expressed as milligrams oxalic acid dihydrate per 24 h urine volume.
TL;DR: Geraniol decomposition in aqueous oxalic acid yields twenty-three identified products, most of which retain the oxidation level of geraniol and result from simple hydration and proton-transfer reactions as discussed by the authors.
Journal Article•
TL;DR: The effects of potassium and nitrogen fertilization on growth, chemical composition, ionic relations, and oxalic acid levels in the Nandi, Kazungula, and Narok cultivars of Setaria sphacelata have been studied and it is shown that the amount of oxAlic acid accumulated is related to the cation-anion balance.
Abstract: The effects of potassium and nitrogen fertilization on growth, chemical composition, ionic relations, and oxalic acid levels in the Nandi, Kazungula, and Narok cultivars of Setaria sphacelata have been studied. Potassium response curves have been derived and their use in predicting 'critical potassium levels' in these grasses discussed. Cation-anion balances (total inorganic cation concentrationndash;total inorganic anion concentration) have been calculated and the effects of potassium and nitrogen fertilization on ionic relations are discussed. The Kazungula and Narok cultivars contained higher levels of the cations calcium, magnesium, sodium, and ammonium when grown under limiting potassium conditions than when supplied with adequate potassium. The Nandi cultivar was similarly affected but did not accumulate sodium. All plants with high levels of potassium in their tissues also contained high levels of nitrate when the nitrogen supply was adequate. The cation-anion balance increased with increasing potassium fertilization in all cultivars but there was an interaction between potassium fertilization and nitrogen fertilization. Potassium and nitrogen fertilization resulted in large increases in oxalic acid levels. It is shown that the amount of oxalic acid accumulated is related to the cation-anion balance.
TL;DR: In this article, it is suggested that the first step of oxidation is the formation of a cyclic intermediate containing manganese(V) and that oxalic acid is formed as an intermediate.
Abstract: Fast reaction techniques have been applied to the study of intermediates in the permanganate oxidation of acetylenedicarboxylic acid in acid. The accumulation and decay of MnIII has been observed by stopped-flow spectrophotometry. The quenching of reacting solutions proves that oxalic acid is formed as an intermediate. The amount of oxalate found in the presence of pyrophosphate as scavenger for MnIII provides evidence for a short-lived MnIV species. Oxygen-18 tracer experiments indicate complete oxygen transfer from permanganate to acetylenedicarboxylic acid. A number of mechanistic alternatives are systematically examined. It is suggested that the first step of oxidation is the formation of a cyclic intermediate containing manganese(V).
Patent•
20 Mar 1972
TL;DR: In this article, a catalyst system formed from a salt or a complex cpd of a Pt metal and a complex of a further metal which is more electropositive than the noble metal is presented.
Abstract: Oxalic acid (esters) are prepd by oxidn of CO in aq or alcoholic phase with O2 under press at elevated temp and using a catalyst system formed from a salt or a complex cpd of a Pt metal and a salt or a complex of a further metal which is more electropositive than the noble metal and which can occur in several oxidn states
TL;DR: In salinity studies on the cultivated tomato, Lycopersicon esculentum Mill, seedlings were grown in solution cultures containing 0, 40, and 120 meq/1 NaCl for observation by X-ray analytical electron microscopy freeze-substitution systems based on diethyl ether and containing additives were tested for their effect on the retention of sodium in young leaf tissue.
Abstract: In salinity studies on the cultivated tomato, Lycopersicon esculentum Mill, seedlings were grown in solution cultures containing 0, 40, and 120 meq/1 NaCl for observation by X-ray analytical electron microscopy Freeze-substitution systems based on diethyl ether and containing additives were tested for their effect on the retention of sodium in young leaf tissue. The additives were picrolonic acid, 2,6-dinitrophenol, alizarin, benzamide, and oxalic acid. Cyanuric chloride was also tested as a nonmetal-containing fixative in the freeze-substitution fluid Only benzamide resulted in the retention of significant levels of sodium in the tissue, and it was also effective for calcium Peak-to-background ratios as high as 6.2 were achieved for sodium and 48 0 for calcium on an X-ray dispersive spectrophotometer of EMMA-4. Distinct differences in the relative amounts of these elements were recorded at different ultrastructural sites in the cells, possibly reflecting their distribution in living tissue The processing...
Patent•
03 Aug 1972
TL;DR: In this paper, a method of anodizing aluminum and its alloys utilizing a suitable anodeizing electrolyte and a pulsed direct current was proposed. But the method was not suitable for aluminum alloys.
Abstract: A method of anodizing aluminum and its alloys utilizing a suitable anodizing electrolyte and a pulsed direct current The direct current used provides a substantially constant anodizing current interspersed with at least six pulses per second of higher, smoothly peaked, direct current It has been found that the greater the number of pulses per second, the more superior the anodic coating obtained The electrolyte used can be sulfuric acid (125 to 300 grams of sulfuric acid per liter of water) preferably containing a 01 to 02 grams per liter of sodium lignosulfonate or other such sulfonated organic compound as a stabilizer A mixture of sulfosalicylic acid and sulfuric acid or a mixture of sulfuric and oxalic acid can be used
TL;DR: In this article, the extraction mechanism for the extraction of zirconium from oxalate solutions and of niobium from fluoride solutions was proposed, and the efficiency of extraction by 2-carbethoxy-5-hydroxy-1-(4-tolyl)-4-pyridone (HA) dissolved in chloroform was studied.
Abstract: Extraction of zirconium, niobium and tantalum from oxalic and hydrofluoric acid solutions, by 2-carbethoxy-5-hydroxy-1-(4-tolyl)-4-pyridone (HA) dissolved in chloroform was studied. Extraction mechanism for the extraction of zirconium from oxalate solutions and of niobium from fluoride solutions is proposed. Separation of zirconium and niobium from oxalate solution as well as from fluoride solution and tantalum and niobium from fluoride solution is described. Back-extraction of these metals is possible by hydrofluoric and oxalic acid. Results obtained show that the efficiency of extraction by HA decreases in the sequence tantalum > niobium > zirconium.
TL;DR: In this article, the decarboxylation of Oxalic acid during the ripening of a Banana Fruit (Musa sapientum L.) is discussed. But the method is not suitable for the handling of animals.
Abstract: (1972). Decarboxylation of Oxalic Acid during Ripening of Banana Fruit (Musa sapientum L.) Agricultural and Biological Chemistry: Vol. 36, No. 11, pp. 2021-2024.
TL;DR: Theoretical calculations of scattering at idealized pores of circular cross-section lying parallel to each and perpendicular to the film surface, using size versus number distributions determined by electron microscopy and a refractive index of the oxide equal to 1.64, gave fair agreement with experiment for sulphuric and oxalic acid films on the basis of water-filled pores, but poor agreement for phosphoric acid films, where interference effects are expected to be important as discussed by the authors.
TL;DR: The presence of mercaptosuccinic acid or oxalic acid was shown to retard the production of dark brown precipitates and the development of highly coloured hydrolysates due to tryptophan degradation.
Patent•
07 Jun 1972TL;DR: In this article, a metal chelate of 5, 14-dihydrodibenzo(5, 9, 14, 18, 18) tetraaza(14)-annulene or an electrochemical oxidation product thereof is used as a catalyst for fuel cell electrodes.
Abstract: A catalyst for fuel cell electrodes wherein a gaseous fuel or a fuel dissolved in the electrolyte of the cell is subjected to anodic oxidation, comprises a metal chelate of 5, 14-dihydrodibenzo(5,9,14,18) tetraaza(14)-annulene or an electrochemical oxidation product thereof. The catalyst permits formation of electrodes which can be operated with an acidic electrolyte and comparatively inexpensive fuel, such as methanol, formaldehyde, formic acid, carbon monoxide, oxalic acid, etc.
Journal Article•
Patent•
Snam1
TL;DR: In this paper, a process for the preparation of an OXIDATION CATALYST based on OXIDES OF ANTIMONY and of a second METAL selected from the group consisting of IRON, URANIUM, TIN, CERIUM, MANGANESE and THORIUM was described.
Abstract: 1. A PROCESS FOR THE PREPARATION OF OXIDATION CATALYST BASED ON OXIDES OF ANTIMONY AND OF A SECOND METAL SELECTED FROM THE GROUP CONSISTING IRON, URANIUM, TIN, CERIUM, MANGANESE AND THORIUM SAID PROCESS COMPRISING (I) PROVIDING A POWDERED CATALYTIC MASS BY HEATING COMPOUNDS OF THE SAID METALS WHICH ARE THERMALLY DECOMPOSABLE TO THE METAL OXIDES, (II) DRYING THE FINELY POWDERED CATALYTIC MASS, (II) ADDING A COMPOUND, VOLATILE AT TEMPERATURE LOWER THAN THE CATALYST ACTIVATION TEMPERATURE, AND SELECTED FROM THE GROUP CONSISTING OF AMMONIUM CARBONATE, AMMONIUM BICARBONATE UREA, HEMAMETHYLENETETRAMINE AND OXALIC ACID, (IV) MOLDING THE CATALYST PREPARATION TO SHAPE, (V) HEATING THE SHAPED CATALYST UNTIL SAID VOLATILE COMPOUND IS COMPLETELY ELIMINATED AND (VI) THEN CALCINING TO OBTAIN THE OXIDES OF THE SAID METALS.
Patent•
18 Aug 1972TL;DR: Glyoxylic acid is prepared by a process facilitating recovery of glyoxylic acids, the process being electrolytic reduction of oxalic acid in an electrolysis cell in which A. The CATHODE is SOLID and METALLIC with a HYDROGEN overvoltage WHICH is GREATER THAN the potential for the REDUCTION of OXALIC ACID to GLYOXYLIC acid.
Abstract: Glyoxylic acid is prepared by a process facilitating recovery of glyoxylic acid, the process being electrolytic reduction of oxalic acid in an electrolysis cell in which A. THE CATHODE IS SOLID AND METALLIC WITH A HYDROGEN OVERVOLTAGE WHICH IS GREATER THAN THE POTENTIAL FOR THE REDUCTION OF OXALIC ACID TO GLYOXYLIC ACID, B. THE SEPARATING DIAPHRAGM IS A CATION EXCHANGE MEMBRANE, C. THE CATHOLYTE COMPRISES AN AQUEOUS SOLUTION OF OXALIC ACID WHICH IS FREE OF A STRONG INORGANIC ACID, D. THE CATHOLYTE MOVING IN A CLOSED PATH BY BEING PASSED INTO THE CATHODE COMPARTMENT, OVER THE SURFACE OF THE CATHODE, BEING REMOVED FROM THERE AND BEING RETURNED TO THE CATHODE COMPARTMENT, AND E. THE TEMPERATURE OF THE CATHOLYTE IS BETWEEN 0* AND 70*C.
Patent•
15 Jun 1972TL;DR: BISOXALIC ACID DIAMINES HAVING the STRUCTURE ((4-HO,3,5-DI((CH3)3-C-)PHENYL)-NH-CO-Co-NH)2-R are STABILIZERS of ORGANIC MATERIALS SUCH AS POLYOLEFINS as mentioned in this paper.
Abstract: BISOXALIC ACID DIAMINES HAVING THE STRUCTURE ((4-HO,3,5-DI((CH3)3-C-)PHENYL)-NH-CO-CO-NH)2-R WHERE R IS AN ALKYLENE GROUP HAVING 5 TO 18 CARBON ATOMS ARE STABILIZERS OF ORGANIC MATERIALS SUCH AS POLYOLEFINS. THESE COMPOUNDS ARE PREPARED BY REACTING AN OXALIC ACID MONOAMIDE OR THE CHLORIDE OR AN ESTER THEREOF WITH AN ALKYLENE DIAMINE.
Patent•
25 Feb 1972
TL;DR: Germanium is extracted from an alum solution utilizing a hydrocarbon solution of a monosubstituted phosphoric acid as the extractant as mentioned in this paper, which is then back extracted with an aqueous oxalic acid solution to recover the germanium component.
Abstract: Germanium is extracted from an alum solution utilizing a hydrocarbon solution of a monosubstituted phosphoric acid as the extractant. The hydrocarbon solution is then back extracted with an aqueous oxalic acid solution to recover the germanium component.
Patent•
18 May 1972
TL;DR: A process for separating and recovering of American aircraft from containers from a "bomber" or "bOMB" reduction is described in this article. But, it does not consider the possibility of adding a base to the aircraft.
Abstract: A PROCESS FOR SEPARATION AND RECOVERY OF AMERICIUM VALUES FROM CONTAINER OR "BOMB" REDUCTION RESIDUES COMPRISING DISSOLVING THE RESIDUES IN A SUITABLE ACID, ADJUSTING THE HYDROGEN ION CONCENTRATION TO A DESIRED LEVEL BY ADDING A BASE, PREDIPITATING THE AMERCIUM AS AMERICAIUM OXALATE BY ADDING OXALIC ACID, DIGESTING THE SOLUTION, SEPARATING THE PRECIPITATE, AND THEREAFTER CALCINING THE AMERICIUM OXALATE PRECIPITATE TO FORM AMERICIUM OXIDE.