1N Sulphuric Acid Research Articles

Spectrophotometric Determination of Domperidone Using δA Method

Abstract A spectrophotometric method for the assay of domperidone tablets (Motilium(R)−10 mg) is described. The mean percentage found for the active ingredient per tablet was 100.61 ± 1.19. The drug exhibits maximum absorption at 282 nm in 0.5 N-sulphuric acid and at 294 nm in 0.5 N-sodium hydroxide due to keto-enol tautomerism. δA at 300 nm proved to be linearly related to the drug concentration in the range 5-30 μg ml−1 with a coefficient of variation 1.09%.

Oestrogen conjugation in mid trimester human fetal brain: A possible role in its sexual differentiation

Mid-trimester human fetal brain cytosol incubated with [ 3H]-oestradiol gave a radioactive peak on 5% polyacrylamide gels, which migrated with the bromophenol blue marker (anodic peak) and which could be suppressed by the addition of 100 times molar excess of unlabelled ligand to the incubate. This anodic peak could only be destroyed by proteolytic enzymes if they were added at the beginning of the incubation, but not subsequently, indicating that it did not represent a protein-bound oestradiol. Competition studies show that the anodic peak can be suppressed with natural oestrogens and ethinyloestradiol, but not by the synthetic oestrogens, androgens and progestins tested. Butanol extraction of incubates, followed by t.l.c. in a number of systems, indicates that both oestrone and oestradiol are sulphated. The parent steroids could be liberated by hydrolysis of incubates with either 1N sulphuric acid or aryl sulphatase. This conjugation may effectively curtail the action in fetal tissues of high levels of oestrogens and hence play a role in brain sexual differentation in the human.

硫酸中の鉄腐食に対する n-アルキルトリメチルアンモニウム硫酸塩の効果

硫酸中の鉄腐食に対する n-アルキルトリメチルアンモニウム硫酸塩の効果

Electrochemical and Morphological Study of Nickel in 1 N Sulphuric, Perchloric and Hydrochloric Acids: Influence of the Purity Grade and of Anion Type

The behaviour of three types of nickel (99·99% {111} single crystal, 99·99% polycrystalline and commercial purity grade polycrystalline) has been investigated in 1N perchloric acid. The electrochemical results and the optical microscopy observations of the surface during and after controlled dissolution are compared with the ones previously obtained under the same conditions in 1N sulphuric acid and in 1N hydrochloric acid.From an analysis of all our data a mechanistic model of nickel dissolution is deduced. It interprets the value of 60 mV for the anodic Tafel slope, found for the high purity nickel, and it considers, as the rate determining step, two possible reactions: (i)proton transfer from the intermediate NiOH2+, electrochemically formed, to a water molecule, and (ii) the movement ofadspecies such as NiOHads from kinks to plane surfaces. The prevailing control of one of these two steps depends on the type of the anion and the purity of the nickel surface.

Phase diagram of the adenine-sulphuric acid-water system and the growth of single crystals of two adenine sulphate salts

A part of the phase diagram of the adenine-sulphuric acid-water system was measured. Competition in the formation of adenine sulphate and adenine hemisulphate hydrate from the solution of 2N sulphuric acid was explained and suitable conditions for the growth of single crystals of both adenine salts were found. Single crystals of adenine hemisulphate hydrate (C 5H 5N 5 · 0.5 H 2SO 4 · H 2O, m.w. 202.25) weighing about 3 g were grown using the method of cooling the solution of adenine or adenine hemisulphate hydrate in 2N sulphuric acid. Composition of the crystals, some of their properties, and their fundamental crystallographic parameters, determined by means of a reflection two-circle goniometer (triclinic system, 1 ), are described.

The influence of radioactive n-dibutyl sulphide on the corrosion and polarization of steel and its electrocapillary behaviour in in sulphuric acid

The corrosion and polarization of steel have been investigated in 1N sulphuric acid, containing n-dibutyl sulphide labelled with radioactive sulphur atom. In addition, the electrocapillary behaviour of the radioactive substance on a mercury surface in the acid has been tested. Similar experiments employing non-radioactive dibutyl sulphide (d.b.s.) and hydrogen peroxide have been carried out. The inhibition of corrosion of steel in IN sulphuric acid by d.b.s. is significantly reduced and under some conditions corrosion is accelerated by the radioactive form. The polarization and the electrocapillary behaviour of radioactive d.b.s. solutions are clearly different from that of the non-radioactive compound. There is some similarity in the effects produced by radioactive d.b.s. and by a combination of non-radioactive d.b.s. and hydrogen peroxide, in respect of corrosion inhibition and electrocapillary behaviour. It is concluded that the effects produced by radioactive d.b.s. can be attributed mainly to the hydrogen peroxide produced by radiolysis, though the radioactivity can also affect the electrical characteristics at the metal-solution interface.

The effect of pyrrole-halide mixtures in inhibiting the dissolution of low-carbon steel in sulphuric acid

A rapid-polarization technique was used to study the mechanism by which the pyrrolehalide inhibitor system affects the corrosion of low-carbon steel in a 2N sulphuric acid solution. Pyrrole primarily inhibits the cathodic reaction, whereas the halides seem to strongly inhibit the anodic reaction. Weight-loss measurements indicated that the corrosion rate of steel rapidly increases with temperature over the range 100–200°F (38–93°C) both in the presence and absence of inhibitors, with an apparent activation energy in all instances of 12.6 kcal/mole.

2, 4‐Dinitrophenylhydrazine as a Corrosion Inhibitor for Copper in Sulphuric Acid

Corrosion rates of copper in 1N sulphuric acid with various concentrations (10−8 to 10−4 M) of 2, 4‐dinitrophenylhydrazine (2, 4‐DNP) are determined by weight loss method. The corrosion rates (under diffusion control), are a function of the stirring rate and the concentration of 2, 4‐DNP. The corrosion rate decreased markedly on increasing the concentration of 2, 4‐DNP. The maximum corrosion inhibition (85%) is observed at 10−4 M 2, 4‐DNP. The anodic polarization data and the drift in corrosion potential with time towards the less noble direction reveal the inhibition of cathodic reaction of the corrosion process by 2, 4‐DNP. A mechanism is proposed to explain the inhibitor action of 2, 4‐DNP on copper during corrosion in 1N sulphuric acid.

A ready synthesis of 5α,14β-cholest-7-en-3β-ol

Reduction of 3β-acetoxy-8α,14α-epoxy-5α-cholestan-7-one or 3β-acetoxy-5α-cholest-8(14)-en-7-one with zinc dust in methanolic N-sulphuric acid yields 3β-acetoxy-5α,14β-cholest-7-ene with minor amounts of 3β-acetoxy-5α,14β-cholestan-7-one, and constitutes a novel, simple synthesis of 14β-steroids.

ChemInform Abstract: THE ELECTROCAPILLARY BEHAVIOUR AND THE CORROSION‐INHIBITIVE NATURE OF SOME ORGANIC SULPHUR COMPOUNDS

Abstract The effects of different organic radicals attached to the sulphide group in dimethyl sulphide,di- n -butyl sulphide, di-phenyl sulphide and thiophene on their electrocapillary behaviour with mercury surface and on their corrosion inhibitive nature with respect to steel in 1N sulphuric acid have been examined. It has been found that (i) there is a qualitative correlation between the electrocapillary behaviour and corrosion inhibitive effect of only some of these sulphides, (ii) the inductive effect of methyl groups enhances the effectiveness of the sulphur atom both in its adsorption on mercury surface and in corrosion- inhibition and (iii) the direct linkage of the sulphur atom to aromatic groups or its incorporation in the aromatic ring brings down the electrocapillary adsorption and the corrosion inhibitive effects of the organic sulphides.

The Electrocapillary Behaviour and the Corrosion-Inhibitive Nature of some Organic Sulphur Compounds

The effects of different organic radicals attached to the sulphide group in dimethyl sulphide,di- n-butyl sulphide, di-phenyl sulphide and thiophene on their electrocapillary behaviour with mercury surface and on their corrosion inhibitive nature with respect to steel in 1N sulphuric acid have been examined. It has been found that (i) there is a qualitative correlation between the electrocapillary behaviour and corrosion inhibitive effect of only some of these sulphides, (ii) the inductive effect of methyl groups enhances the effectiveness of the sulphur atom both in its adsorption on mercury surface and in corrosion- inhibition and (iii) the direct linkage of the sulphur atom to aromatic groups or its incorporation in the aromatic ring brings down the electrocapillary adsorption and the corrosion inhibitive effects of the organic sulphides.

The effect of shock deformation on the anodic polarization behavior of polycrystalline nickel in 1N sulphuric acid

The results of anodic potentiostatic polarization of shocked nickel polycrystals in 1N H 2SO 4 are reported. With increasing shock pressure, passivation and Flade potentials shift in the cathodic direction, the critical current density decreases, and the passive current density decreases. These effects are discussed in terms of substructural changes accompanying shock loading.

Quantitative determination with periodate of compounds subject to non-malapradian oxidation. Part I. Methyl ethers of polyhydroxy-compounds

Compounds which give rise to the 2-methyl ether of triose reductone (2-methoxymalonaldehyde) have been reported to undergo non-stoicheiometric ‘over-oxidation’ reactions. The behaviour of four such compounds, 3-O-methyl-D-xylose, 3-O-methyl-D-glucose, (–)-quebrachitol [5-O-methyl-(–)-inositol-(1,2,4/3,5,6)], and (+)-pinitol [6-O-methyl-(+)inositol-(1,2,5/3,4,6)], towards periodate in 0·1N-sulphuric acid at 0°, has been examined. Under these conditions, the methoxymalonaldehyde formed as the result of glycol cleavage reacts stoicheiometrically with periodate: it reduces two molar equivalents of the oxidant and yields one equivalent each of formic and glyoxylic acids. The possible pathways for this oxidation are discussed.

Coal Tar Base Fractions as Pickling Inhibitors in Hydrochloric and Sulphuric Acid Solutions

AbstractFour coal-tar-base fractions were found to be effective in preventing the dissolution of low-carbon steel and in limiting the absorption of hydrogen by steel during pickling in 2 N- and 4 N-hydrochloric acid at 100° and 150°F. The crude quinoline bases and distilled quinoline bases were also effective inhibitors in 2 N-sulphuric acid solutions at 100°F, but at 200°F these same fractions afforded no better than 78% inhibition when tested at 0·25 vol.-%.Previous investigations have shown that NaCl, NaBr and NaI are moderately effective inhibitors in 2 N-sulphuric acid at 200°F. In the presence of coal-tar bases, these and other inorganic halides display a remarkable synergistic effect. When used at relatively low halide concentrations, the inhibitor properties of the mixtures are much better than those of the halides or tar bases used alone in sulphuric acid. The superior performances of the tar-base fractions in HCl may be associated with the fact that HCl is a halogen acid. Moreover, the tar base–...

The reactions of thiourea with some chloropyrazines and their N-oxides

1,2-Dihydro-2-thionopyrazines and their 4-oxides have been prepared from the corresponding chloro-compounds and thiourea using 2N-sulphuric acid as reaction medium.

BENZOIC ACID DERIVATIVE IN THE SECRETA OF THE GENITAL EPITHELIUM OF THE COW.

The secretion of citric acid by the bovine female genital epithelium has been investigated by Gaspar & Cseh (1963). In 60% of cases no citric acid was present, but in the secreta of 40% of the cows, quantities corresponding to spots of 1 ·5 to 40 μg could be demonstrated. In 30% of the investigated cases one unidentified spot, usually accompanied by citric acid and showing Rf values from 0·78 to 0·80, also appeared on the chromatogram. We have been trying to identify more closely the compound forming this spot. It was diffusible and remained unhydrolysed in 1 n-sulphuric acid for 2 hr and was in character acid. Although the unknown compound was generally accompanied by citric acid, it could not be identified either with lactic acid, pyruvic acid and the components of the

Über den elektrochemischen aufbau und abbau von sauerstoff- und wasserstoff-belegungen auf platin in wässriger lösung

The chemisorbed oxygen and hydrogen layers formed on platinum by anodic and cathodic polarization respectively have been investigated by means of charging curves. In cathodic polarization of a platinum electrode in 1N sulphuric acid at low current densities (e.g. 25 μA/cm 2, the coverage of the platinum reaches only half a monolayer of hydrogen atoms even at steady-state hydropen evolution. In a following anodic polarization with low c.d. this chemisorbed hydrogen layer undergoes disintergation accompanied by a rise in potential. After a further increase of potential during which only charging of the double layer takes place, there follows chemisorption of oxygen which the gradually changes over to the formation of a surface oxide film, two to three monolayers thick. Finally film formation becomes so slow that oxygen evolution predominates. In a now following cathodic polarization, the surface oxide including part of the chemisorbed oxygen layer is reduced to hydroperoxide primarily. The remaining part of the chemisorbed oxygen is not reduced until chemisorption of hydrogen has already set in. As a result of the reduction of the oxide film a loosely packed layer of platinum atoms for some time; it rearranges gradually to the normal lattice. This appears to be the reason for the increased activity of platinum electrodes in partly cathodic redox reactions after anodic pre-treatment. The potentials, referred to a hydrogen electrode in the same solution, in the case of the anodic formation of the chemisorbed oxygen layer and the surface oxide film were 0·8 to 1·3 V. The corresponding potentials during the reduction of the chemisorbed oxyen and the oxide film were within a somewhat lower region, 0-1 V. The potential of the chemisorbtion of hydrogen was between 0.3 and 0 V, decreasing linearily with the fraction of coverage

Beobachtungen an Einem Kornzerfallsan-Falligen Austenitischen Chrom-Nickel-Stahl im Aktivzustand

18/10 chrome-nickel steel samples, sensitized to intergranular corrosion by heating at 550°C, when immersed in boiling 1N sulphuric acid give rise to oscillations of both potential and polarization current when the circuit resistance exceeds a certain value. These oscillations are connected with intergranular corrosion, and they are also observed in other solutions which give rise to intergranular attack (e.g. HF/HNO 3). Samples heated at 675°C are neither prone to intergranular corrosion nor do they show oscillations at the active corrosion potential. Possible processes concerning the periodic phenomena are discussed in connection with known dynamic behaviour of active iron. Besides electrochemical and dynamic properties there is also a certain geometric shape of the corrosion grooves at the grain boundaries connected with the periodic phenomena.

METABOLISM OF PLANT GROWTH REGULATORS

2,4‐Dichlorophenoxyacetic acid (2,4‐D) labelled with 14C in either the carboxyl or methylene group was fed through the transpiration stream into detached leaves of black currant, which is sensitive to this herbicide, and of red currant which is highly resistant. The leaves were then kept in darkness and the evolution of 14CO2 was followed; subsequently the leaves were extracted and the metabolic products examined by chromatography and radioassay.The chief difference between the species is the ability of the red‐currant leaf to oxidize approximately 50% of the carboxyl and 20% of the methylene carbon from the side chain of the 2,4‐D over a period of 1 week: in the black‐currant leaf only about 2% of the 2,4‐D is broken down in this way in the same period. The red‐currant leaf can metabolize in a similar manner the side chains of 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T), 4‐chlorophenoxyacetic acid (4‐CPA) and 2‐methyl‐4‐chlorophenoxyacetic acid (MCPA), but not of 2‐chlorophenoxyacetic acid (2‐CPA).In both species 5–10% of the 2,4‐D taken up by the leaves is converted to water‐soluble compounds which are biologically inactive in the oat mesocotyl and Coleus abscission tests and which yield 2,4‐D on hydrolysis with 2N sulphuric acid. The failure of 2‐CPA to produce growth responses in currants, and probably in other plants, is attributable to the conversion of 70–80% of the applied chemical to water‐soluble inactive compounds. A further 5–10% of the 2,4‐D entering the leaf is metabolized to a biologically active, non‐acidic neutral compound. Analogous compounds were formed in leaves treated with 2,4,5‐T or 2‐CPA.In both species a variable proportion (10–30%) of 2,4‐D, 2,4,5‐T and 2‐CPA are bound in the leaf tissue and cannot be removed by aqueous or organic solvents or by mild hydrolysis.The red currant is killed by low concentrations of 2,4,5‐T even though this compound is broken down in the leaf as rapidly as 2,4‐D. It is noteworthy that death is delayed and there is an absence of the epinastic reactions normally associated with damage by phenoxy‐acid herbicides.

The reaction of lactose with anthrone and its application to the estimation of lactose in casein and other dairy products

Lactose was estimated accurately and rapidly in casein by use of anthrone reagent on the clear filtrate from precipitation of a sodium bicarbonate solution of the casein with 0·1 n-sulphuric acid. The reagent consists of 0·15% (w/v) anthrone in 70% (v/v) sulphuric acid. The ice-cold anthrone solution (10 ml.) was added, with cooling, to 1 ml. of the ice-cold solution containing 0–100 µg. of lactose. The mixture was heated at 100° C. for 6 min. and cooled for 30 min. The optical density of the coloured solution was then measured at 625 mµ