Showing papers on "Oxalic acid published in 1973"
TL;DR: In this paper, a method of making a laser body from a high density yttria-based ceramic material is provided, which involves forming an aqueous solution containing water soluble salts of yttrium, thorium, and neodymium, coprecipitating the cations from solution with oxalic acid, recovering the oxalate precipitate in the form of a purified dried powder, calcining the powder to convert oxalates to oxides, particulating the oxides in a rubber-lined ball mill, pressing the powdered oxides into a
Abstract: A method of making a laser body from a high density yttria-based ceramic material is provided. The method involves forming an aqueous solution containing water soluble salts of yttrium, thorium and neodymium, coprecipitating the cations from solution with oxalic acid, recovering the oxalate precipitate in the form of a purified dried powder, calcining the powder to convert the oxalates to the oxides, particulating the oxides in a rubber-lined ball mill, pressing the powdered oxides into a "green body", sintering the "green body" in a hydrogen atmosphere and rapidly cooling the sintered body to form an improved lasing ceramic material.
182 citations
Patent•
29 May 1973TL;DR: In this paper, a process for removing radioactive scale from a ferrous metal surface is described, including the steps of initially pre-conditioning the surface by contacting it with an oxidizing solution (such as an aqueous solution of an alkali metal permanganate or hydrogen peroxide), then, after removal or decomposition of the oxidising solution, the metallic surface is contacted with a cleaning solution which is a mixture of a mineral acid and a complexing agent ( such as sulfuric acid and oxalic acid), and which preferably contains a corrosion inhibitor.
Abstract: A process for removing radioactive scale from a ferrous metal surface, including the steps of initially pre-conditioning the surface by contacting it with an oxidizing solution (such as an aqueous solution of an alkali metal permanganate or hydrogen peroxide), then, after removal or decomposition of the oxidizing solution, the metallic surface is contacted with a cleaning solution which is a mixture of a mineral acid and a complexing agent (such as sulfuric acid and oxalic acid), and which preferably contains a corrosion inhibitor. A final step in the process is the treatment of the spent cleaning solution containing radioactive waste materials in solution by adding a reagent selected from the group consisting of calcium hydroxide or potassium permanganate and an alkali metal hydroxide to thereby form easily recovered metallic compounds containing substantially all of the dissolved metals and radioactivity.
77 citations
TL;DR: Experiments with specifically labeled substrates suggest a path of conversion involving cleavage of l-ascorbic acid, or a metabolic product of l -ascorbIC acid, between C(2) and C(3), such that oxalic acid arises from the two carbon fragment and (+)-tartaric acid from the four carbon fragment.
Abstract: Metabolic conversion of l-galactono-1, 4-lactone and l-ascorbic acid to (+)-tartaric acid and oxalic acid has been studied in Pelargonium crispum, cv. Prince Rupert. Experiments with specifically labeled substrates suggest a path of conversion involving cleavage of l-ascorbic acid, or a metabolic product of l-ascorbic acid, between C2 and C3, such that oxalic acid arises from the two carbon fragment and (+)-tartaric acid from the four carbon fragment.
58 citations
TL;DR: This catalyzed hydrolysis demonstrates that this system does not contain compounds with peptide links and the oligomerization products are susceptible to oxidizing agents but are affected little by reducing agents.
38 citations
TL;DR: Results showed that the isolated bromine compound corresponded well to 1-methylheptyl-γ-bromoacetoacetate (synonym of 2-octyl- δ-cadmium-2,5-dioxocyclohexane-1,4-dicarboxylate).
35 citations
Patent•
10 Jan 1973TL;DR: In this paper, a stable aprotic solvent (e.g. propylene carbonate) and at least 1 stable conducting salt are used to prevent oxalate-anions formed at the cathode.
Abstract: is electrochemically reduced, using an electrolytic cel contng. a stable aprotic solvent (e.g. propylene carbonate) and at least 1 stable conducting salt (e.g. a tetra-1-4C-alkyl-ammonium carbonate) dissolved therein, the cell comprising a cathode (e.g. a Cr-Ni-steel) which consists of an electrical conductor that does not chemisorb the CO2, and of an anode (e.g. a noble metal such as Pt). The cathode is kept free of reducible cpds. and the anode is kept free of oxalate-anions formed at the cathode. This may be achieved by interposing ion exchange membranes. Electro-chemical reduction of CO2 in protic solvents (water) has in the past resulted in the formation of formic acid. The prodn. of oxalic acid by the claimed process has been made possible by using suitable aprotic solvents, conducting salt and material for the electrodes.
32 citations
01 Sep 1973
TL;DR: In this article, the magnetic shielding anisotropies for carboxylic, aliphatic, olefinic and aromatic protons are obtained for powder samples of anhydrous oxalic acid.
Abstract: Proton multiple pulse spectra of powder samples of anhydrous oxalic acid, oxalic acid dihydrate, malonic-, succinic-, phthalic-, maleic- and fumaric acid. succinic-, phthalic- and maleic acid anhydride, and ferrocene have been recorded at 90 MHz. The spectra are analysed in terms of the nuclear magnetic shielding anisotropy Δσ= σ⊥ - σ⊥. No evidence for non-axially symmetric shielding has been obtained. The shielding anisotropies seem to reflect at least qualitatively the immediate electronic environment of the protons under study. The anisotropies obtained for carboxylic, aliphatic, olefinic and aromatic protons are ≈ + 18, ≈ +10, ≈ ± 0 and ≈ −5 ppm with substantial variations among the various compounds studied.
30 citations
29 citations
Patent•
14 May 1973
TL;DR: In this article, the authors proposed a method for providing chemiluminescent light from a chemical reaction of suitable oxalate-type compounds with hydroperoxides in the presence of a fluorescent compound and a diluent.
Abstract: Devices for providing chemiluminescent light from a chemical reaction of suitable oxalate-type compounds with hydroperoxides in the presence of a fluorescent compound and a diluent, in which the oxalate chemiluminescent component is incorporated with a substrate, and the component providing the reaction is applied to the substrate as a fluid, i.e., liquid or vapor.
27 citations
TL;DR: In this article, the permanganate oxidation of maleic and fumaric acids has been studied in acidic solutions and the product distribution has been determined as a function of the pH and the mole ratio of the reactants.
Abstract: The intermediates in the permanganate oxidation of maleic and fumaric acids have been studied in acidic solutions. The accumulation and decay of manganese(III) has been demonstrated by the stopped-flow technique. The concomitant four-electron oxidation of the substrates leads to the formation of formyl(hydroxy)acetic acid. The subsequent reactions reveal a complex pattern in which hydroxymalonic, glyoxylic, and oxalic acid are further intermediates. The product distribution has been determined as a function of the pH and the mole ratio of the reactants. A reaction scheme is suggested which rationalises the observed behaviour.
24 citations
TL;DR: Study of plasma protein binding of oxalic acid showed extensive binding at pH 6 and below, which suggests that previously reported assays involving acid deproteinization probably result in extensive losses of Oxalate bound to protein.
TL;DR: In this article, the oxalic acid, calcium and phosphorus contents, calcium/oxalic acids and calcium/phosphorus ratio of 10 leaves, edible portion of 14 oxalate rich leafy vegetables and 105 other foods are presented.
Abstract: Oxalic acid, calcium and phosphorus contents, calcium/oxalic acid and calcium/phosphorus ratio of 10 leaves, edible portion of 14 oxalate rich leafy vegetables and 105 other foods are presented in this paper. Three leafy vegetables, viz., Amaranth and twoChenopodium species were found to accumulate abnormally large amounts of oxalic acid. Substantial amounts of oxalic acid were also detected in the edible portions of 14 leafy vegetables examined. Moderately high contents of oxalic acid were recorded in all varieties of tea leaves. Appreciable amounts of oxalic acid were also observed in almond, brinjal, carrot, coconut, colocasia, gingelly sleeds (black and white), kamrak, karonda, tamrind (pulp), wood apple and yam. It could not be detected in 15 food items. Stem part present in edible portion of leafy vegetables decreases the oxalic acid intake but not substantially. 28 foods had calcium/oxalic acid ratio less than 0.3 and out of these 23 had below 0.2. Calcium/phosphorus ratio was less than unity in 75 foods items.
Patent•
16 Jan 1973
TL;DR: In this paper, a solution of oxalic acid, manganese, fluoride, and sulphur-and oxygen-containing compounds was used to obtain useful oxalate coatings on low-iron noble alloys.
Abstract: Coatings that facilitate the cold mechanical deformation of stainless steels and particularly of low-iron noble alloys are applied by contacting the metals with an acidic aqueous oxalate coating solution comprised of a solution of oxalic acid, manganese, fluoride, and sulphur- and oxygen-containing compounds. This coating solution not only increases the rate with which a coating may be deposited on more conventional stainless steels, but also makes it possible, for the first time, to obtain useful oxalate coatings on certain low-iron noble alloys utilizing practical levels of chemical activity of the bath.
TL;DR: In this article, a procedure for separating 238Pu from a Np sample irradiated with neutrons is described, and the decontamination factors of the crude products were of the order of 102 for gross γ-activity.
Abstract: A procedure for separating 238Pu from a Np sample irradiated with neutrons is described. Rapid separation of Pu by HDEHP solvent extraction was attempted, and without adjusting its valency states in the dissolver solution of the sample. Both Pu(IV) and Pu(VI) were extracted along with Np from the HNO3 solutions of various concentrations. The Pu and Np extracted in the organic solution were back-extracted with oxalic acid solutions. The decontamination factors of the crude products were of the order of 102 for gross γ-activity. The Pu in the products was separated from Np by means of ion exchange resin columns. Approximately 0.5 mg of 238Pu was obtained with an efficiency exceeding 95%.
Patent•
02 May 1973
TL;DR: Combustion mixtures consisting essentially of powdered red phosphorus particles coated with a liquid unsaturated organic compound selected from the group consisting of vinyl hydrocarbons, hydrocarbon substituted ethylenes, unsaturated carboxylic acids and esters of unsaturated CARBYCLIC acids, or with a polymeric resin formed by autoxidation of said liquid organic compound are useful as a smoke-generating device as discussed by the authors.
Abstract: Combustion mixtures consisting essentially of powdered red phosphorus particles coated with a liquid unsaturated organic compound selected from the group consisting of vinyl hydrocarbons, hydrocarbon substituted ethylenes, unsaturated carboxylic acids and esters of unsaturated carboxylic acids, or with a polymeric resin formed by autoxidation of said liquid organic compound; an oxidizing agent selected from the group consisting of metal carbonates, alkali metal sulphates and alkaline earth metal sulphates; and oxalic acid or urea. The combustion mixture is useful as a smoke-generating device.
TL;DR: In this paper, the infrared spectra of trichloroacetic acid and oxalic acid were obtained, in the 1500-200 cm −1 range, in order to attempt confirmation of recent neutron spectroscopic investigations.
Patent•
28 Jun 1973
TL;DR: In this article, a process for obtaining a ferromagnetic chromium dioxide having granulometric and magnetic characteristics varying within a very wide range, starting from hydrated chromium (III) chromate or from mixtures of metal chromium and chromium oxide having a valency greater than 4, by heating up to between 300 DEG and 500 DEG C under an oxygen pressure of 30-1000 atm, characterized in that the variations of the granulometry and of the magnetic characteristics are obtained by regulating the heating, by means external to the reaction mass or by adding to
Abstract: A process is disclosed for obtaining a ferromagnetic chromium dioxide having granulometric and magnetic characteristics varying within a very wide range, starting from hydrated chromium (III) chromate or from mixtures of metal chromium and chromium oxide having a valency greater than 4, by heating up to between 300 DEG and 500 DEG C under an oxygen pressure of 30-1000 atm., characterized in that the variations of the granulometry and of the magnetic characteristics are obtained by regulating the heating, by means external to the reaction mass or by adding to the starting materials from 0.05 to 30% by weight (with respect to the chromium present) of compounds that decompose exothermically between 100 DEG and 270 DEG C under reaction conditions that lead to CrO2 by favoring the reduction to CrO2 in such a way that the reaction mass will cross the temperature interval of from 200 DEG to 300 DEG C in pre-established times, depending on the granulometry and coercive force desired in the product. Suitable exothermically decomposing compounds include ammonia, oxalic acid, lactic acid, citric acid, and tartaric acid. A novel ferromagnetic chromium dioxide is also disclosed.
TL;DR: In this paper, the role of adsorbed species in the oxidation of oxalic acid was studied by the simultaneous application of tracer techniques and electrochemical methods, and it was established that there is a difference between results at preoxidized and non-oxidised surfaces.
Patent•
18 Oct 1973TL;DR: Trakis(hydroxymethyl)phosphonium oxalate is prepared by reacting formaldehyde with phosphine and oxalic acid with vigorous agitation without the use of a catalyst as discussed by the authors.
Abstract: Tetrakis(hydroxymethyl)phosphonium oxalate is prepared by reacting formaldehyde with phosphine and oxalic acid with vigorous agitation without the use of a catalyst. The product is useful as a flame retardant for cellulose fabrics.
Patent•
07 Aug 1973TL;DR: In this article, a process for preparing high molecular weight aryl alkyl polymers is disclosed, wherein oxalic acid and paraphenylene diisocyanate are reacted in substantially stoichiometric amounts in a polar, aprotic anhydrous organic solvent at a temperature which is raised progressively at a rate of about 1 to about 5°C per minute from a lower temperature of about 0° to 30° C to a higher temperature of approximately 80° to about 150°C in the presence of, at least when the viscosity of the reaction mixture
Abstract: A process for preparing high molecular weight aryl alkyl polymers is disclosed, wherein oxalic acid and paraphenylene diisocyanate are reacted in substantially stoichiometric amounts in a polar, aprotic anhydrous organic solvent at a temperature which is raised progressively at a rate of about 1 to about 5°C per minute from a lower temperature of about 0° to 30° C to a higher temperature of about 80° to about 150°C in the presence of, at least when the viscosity of the reaction mixture exceeds 6,000 poises, a viscosity reducing amount of a hydrogen bond breaking agent, such as lithium chloride. The resulting polymers can be formed into filaments, fibers and films, and the filaments exhibit improved tensile strengths and modulus of elasticity as compared to similar filaments of other arylalkyl polymers based on oxalic acid and other aromatic diisocyanates.
TL;DR: In this article, a method for electrodepositing carrier-free 54Mn, 99Tc and 228Ac separately on a nickel cathode is described, where the nuclides are deposited to better than 95 per cent from an urea oxalate aqueous bath.
TL;DR: If the nephrotoxicity of methoxyflurane is secondary to the products of its metabolism, increased microsomal enzyme activity resulting from prior exposure to drugs such as phenobarbitone would predispose to increased toxicity.
Abstract: The effect of phenobarbitone on the metabolism of methoxyflurane in the rat was investigated. The conversion of methoxyflurane to oxalic acid was confirmed. Pretreatment with phenobarbitone resulted in a further increase in oxalic acid output indicating an acceleration of the biotransformation of methoxyflurane. If the nephrotoxicity of methoxyflurane is secondary to the products of its metabolism, increased microsomal enzyme activity resulting from prior exposure to drugs such as phenobarbitone would predispose to increased toxicity.
TL;DR: In this article, a water insoluble laminaran-like polysaccharide was extracted from Sargassum linifolium by extraction with hydrochloric acid and oxalic acid solutions.
Abstract: Isolation of water insoluble laminaran-like polysaccharide has been achieved fromSargassum linifolium by extraction with hydrochloric acid and oxalic acid solutions. The conditions of the extraction with both acid solutions were studied. The quality of the isolated products was also evaluated.
TL;DR: In this paper, a reaction mechanism for radiolysis of oxalic acid solutions is proposed, which is based on the same type of radicals observed recently in pulse radiolysys of the system.