Ferrous Oxalate Research Articles

The reaction of simple aromatic nitro-compounds with transition-metal oxalates: the question of nitrene intermediates

Azo- and azoxy-benzenes and phenazines were obtained by heating nitrobenzene derivatives with transition-metal oxalates, but not in their absence. Traces of primary amines were isolated occasionally. The formation of the azo- and azoxy-benzenes was shown to be an intermolecular process. It is suggested that the results are best explained in terms of a nitrene intermediate bound to the surface of the metal derivative. The reaction of some nitrosobenzene derivatives with ferrous oxalate was also examined with similar results.

The thermal decomposition of ferrous oxalate dihydrate

Conflicting results have been published on the decomposition of ferrous oxalate dihydrate. The thermal decomposition has been studied by thermogravimetric analysis and differential thermal analysis in carefully controlled atmospheres. The decomposition has been found to be very sensitive to oxygen. Use of 3 mg samples in oxygen atmospheres has shown conclusively that decomposition proceeds via a dehydration followed by decomposition of the anhydrous oxalate. Discrepancies in other published results are caused by poor atmosphere control.

Influence of atmosphere on the thermal decomposition of ferrous oxalate dihydrate

The thermal dehydration and decomposition of ferrous oxalate dihydrate has been studied by thermograyimetric and differential thermal analyses in air, nitrogen and carbon dioxide atmospheres. In nitrogen and carbon dioxide the two endothermic stages of the dissociation were well defined and commenced at 140°C and 320°C yielding FeO as the primary reaction product which later disproportionates to Fe and Fe 3O 4. In air the decomposition of the anhydrous oxalate was found to be exothermic and commenced at a temperature close to 200°C. It is proposed that a different mechanism of decomposition occurs in the presence of oxygen which involves the oxidation of the Fe 2+ cation as the first step in the decomposition which yields Fe 2O 3 as the final product.

The thermal decomposition of oxalates. Part IX. The thermal decomposition of the oxalate complexes of iron

The thermal and X-ray analysis has been made of the decomposition of the trisoxalato-complexes potassium ferric oxalate, sodium ferric oxalate, and ammonium ferric oxalate. The reaction stoicheiometry is described, and the thermal properties of the ammonium complex have been compared with those of ferrous oxalate and ferric oxalate where the end-product in each case is the same.

Some reactions of 3-acetamido-2-nitrobenzo[b]thiophen and its 5-chloro- and 5-bromo- derivatives

The oximes of 3-acetylbenzo[b]thiophen and its 5-chloro- and 5-bromo- derivative underwent the Beckmann rearrangement (80–90%). The resulting amides were nitrated to give (80%) the compounds mentioned in the title. On treatment with ferrous oxalate at 225°, each of these gave a mixture of the corresponding 3-cyano-1,2-benzisothiazole and its 3-carbonamide. 5-Chlorobenzo[b]thiophen-2,3-dione was prepared by a standard route from 5-chloro-3-hydroxybenzo[b]thiophen. On treatment with hydrogen peroxide and ammonia it gave 5-chloro-1,2-benzisothiazole-3-carbonamide, which was converted into the nitrile by heating with phosphorus pentoxide. 1,2-Benzisothiazole-3-carbonamide, and the corresponding nitrile, were similarly prepared from benzo[b]thiophen-2,3-dione. The resulting amides and nitriles were identical with those obtained from the ferrous oxalate reactions. 2,3-Diacetamidobenzo[b]thiophen was prepared by the catalytic reduction of 3-acetamido-2-nitrobenzo[b]thiophen, and acetylation of the resulting unstable amine. It was converted into an imidazole derivative by boiling with dilute hydrochloric acid.

Photochemical Determination of Oxalate.

Oxalate determination in two methods based on photochemical decomposition of ferric oxalate complexes in aqueous acidic solution

The thermal decomposition of ferrous oxalate dihydrate

The action of heat on ferrous oxalate dihydrate results in dehydration, followed almost immediately by decomposition. The anhydrous salt can, however, be isolated, and X-ray powder diffraction data, not previously available in detail, are given for the anhydrous phase. The thermal decomposition has been studied thermogravimetrically and by differential thermal analysis, and the products of decomposition have been identified by X-ray powder diffraction analysis. Earlier work on the subject is surveyed, and the mechanism of decomposition is examined.

Low-Temperature Magnetic Susceptibility of Ferrous Oxalate Dihydrate

The magnetic susceptibility ${\ensuremath{\chi}}_{p}$ of powdered Fe${\mathrm{C}}_{2}$${\mathrm{O}}_{4}$\ifmmode\cdot\else\textperiodcentered\fi{}2${\mathrm{H}}_{2}$O has been measured between 1.3 and 300\ifmmode^\circ\else\textdegree\fi{}K. Above \ensuremath{\sim}80\ifmmode^\circ\else\textdegree\fi{}K, ${\ensuremath{\chi}}_{p}=\frac{3.40}{(T+25.4)}$ (cgs/mole). ${\ensuremath{\chi}}_{p}$ exhibits a broad, rounded maximum near 30\ifmmode^\circ\else\textdegree\fi{}K and a sharp peak at 20\ifmmode^\circ\else\textdegree\fi{}K. X-ray structural evidence indicates that ${\mathrm{Fe}}^{++}$ions in this material are linked in chains by oxalate groups. Assuming an antiferromagnetic intrachain exchange constant $J=\ensuremath{-}4.9k$, it is possible to obtain a reasonable fit of the data above 25\ifmmode^\circ\else\textdegree\fi{}K with the susceptibility computed for Ising interactions and $S=2$. If the upper maximum is due to chain ordering, the lower maximum then appears to be associated with the cooperative onset of long-range spin order in three dimensions induced by interchain coupling.

The thermal decomposition of oxalates. Part VI. The decomposition and surface properties of ferric oxalate

Ferric oxalate on thermal decomposition produces an oxide with a porous structure which differs according to the nature of the heat treatment. In particular, there is a marked difference between samples heated directly at temperatures around 400°C and samples heated to this temperature after previous heat treatment at 190°. This is associated with the rapidity of the transformation from an amorphous to a crystalline modification of ferric oxide at about 400°.

A Mössbauer Resonance Absorption Study of the Photolysis and Radiolysis of Ferric Oxalate

A Mössbauer Resonance Absorption Study of the Photolysis and Radiolysis of Ferric Oxalate

Magnetic Materials Obtained from Silicate Melts in the System Fe<sub>2</sub>O<sub>3</sub>-MnO-Alkali Oxide-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>

Most commercial products of ferrites are made by firing preformed powder mixtures of raw materials. This conventional method, however, is not adapted for obtaining products of the special shapes such as fiber and film. In this study we undertook to examine the possibility of obtaining magnetic materials from melted silicates containing Fe2O3 and MnO and of forming the melts into desired shapes by the ordinary glass-forming technique.The compositions of the melts studied were of 7.5-20% Fe2O3, 7.5-20% MnO (or CoO and NiO), 0-5% Li2O (or Na2O and K2O), 0-15% Al2O3, and 55-70% SiO2(mole). The raw materials were ferrous oxalate, manganese dioxide, cobaltic oxide, nickel oxide, lithium-, sodium- and potassium carbonates, aluminium hydroxide and potter's flint powders. Their mixtures to yield about 50 gram of melts were heated in sintered-alumina crucibles in an electric furnace at temperatures from 1300° to 1400°C. Their melting behaviors and the workability of their melts into shapes of fiber or plate during cooling were investigated. X-ray diffraction analysis and magnetic measurement were made on materials quenched in air.The results obtained are as follows:1) The melts of the compositions, 7.5-15% Fe2O3, 7.5-20% MnO, 0-5% Li2O (or Na2O and K2O), 5-15% Al2O3, 55-70% SiO2 (mole) were fluid at temperatures 1300°-1400°C, and were able to be formed into desired shapes during cooling.2) The intensity of magnetization of quenched specimens reached up to 18 gauss/g at the field of 10, 000 oersteds. Magnetization increased with increasing the content of Fe2O3 or Fe2O3+MnO, and decreased with increasing the content of Al2O3. The specimens of high Fe2O3 content saturated magnetically at a fairly weak magnetic field whereas the specimens of Fe2O3 content less than 15mole% did not saturate even at the field as strong as 5, 000-10, 000 oersteds. The followings are some examples of the composition which showed high magnetization and magnetic saturation at a weak magnetic field.3) Separation of fine crystallites of spinel-type ferrites was confirmed by X-ray analysis in some of quenched specimens containing high amount of Fe2O3. The average size of the crystallites estimated from the broadening of X-ray diffraction peaks was 60-150A.4) Reheating quenched specimen generally increased the intensity of magnetization and also accelarated magnetic saturation at weak magnetic field.

一酸化炭素による亜鉄酸銅の分解

The effects of roasting temperature, carbon monoxide concentration and PCO2/PCO ratio of CO-0O2-N2 atmosphere on the reduction rate of copper ferrite were investigated.Copper ferrite was made from the stoichiometric mixture of cupric oxalate and ferrous oxalate by consecutive thermal treatments for 5 hrs at 1, 000°C and for 5 hrs at 800°C.Reduction products at the first stage were porous metallic copper and magnetite, and at the second stage the magnetite was further reduced to wustite according to the conditions in which PCO2/PCO ratio was 1. 3 and roasting temperatures were 700°C and 800°C.3CuFe2O4+4CO3=3Cu+2Fe3O+F4CO2 (1)Fe3O4-1-CO=3FeO+CO2 (2)Rhombohedral copper ferrite CuFeO2 as an intermediate phase of the reduction products was not detected in the reaction (1).A reacted quantity of copper ferrite in the roasting was linearly proportional to a reaction time, that is to say, the reaction rate is constant, r=dx/dt=k, xm=ktK is proportional to pco4/5 within a range of this study and the energy of activation of the reaction (1) is 1.9 kcal/mol, therefore it is considered that the velocity controlling step of the reaction (1) is a diffusional process.The magnetite as a reduction product of copper ferrite was very easily soluble in 0.1N H2SO4solution. The leach solution of the reduction products contains Cu2+ ion, Fe2+ ion and very little amount of Fe3+ ion. This can be explained by the fact that the metallic copper is corroded with Fe3+ ion, while Fe3+ ion is reduced to a Fe2+-state at the same time. Accordingly, the larger the amount of dissolved magnetite is, the more copper is leached into the solution. Even though a much amount of oxide of iron is dissolved, the quantity of leached copper is small when the oxide of iron exists as wustite only.From the above-mentioned facts, it is concluded that iron oxide as a reduction product of copper ferrite must be needed to exist as wustite because it is required to let metallic copper remain as it is, considering the separation of zinc oxide from metallic copper by only dilute sulfuric acid leaching after a selective reduction roasting of dead roasted complex sulfide ores.

Zinc-Ferriteに関する研究 (第3報)

The effects of decomposition temperature of ferrous oxalate and of formation temperature of zinc-ferrite on the rate of dissolution in dilute sulfuric acid were investigated.Six species of zinc-ferrite were formed at 900 and 1, 190°C from the stoichiometric mixtures of ferric oxide, which was prepared by thermal decomposition of ferrous oxalate at 500, 700 and 900°C, and zinc oxide.From the previous result that the rate of dissolution is approximately proportional to the surface area, pparent rate constant K (dependent on surface area) and rate constant κ(independent of surface area) of each specimen can be calculated.Apparent rate constant K of zinc-ferrite, which was formed at 900°C, varies with the decomposition temperature of ferrous oxalate, but rate constant κ remains constant. This means that the difference of K arises mainly from surface area of zinc-ferrite, and that decomposition temperature of ferrous oxalate has no influence on the property of zinc-ferrite.The zinc-ferrite, which was formed at 1, 190°C, dissloves with the rate lower than that of zinc-ferrite formed at 900°C. But, when κ were compared, k of zinc-ferrite formed at 1, 190°C are higher than those of zinc-ferrite formed at 900°C, except when the ferric oxide prepared at 500°C was used. This means that, considering the rate of dissolution per unit area, the zinc-ferrites, which were formed at 1, 190°C, dissolve more easily than those formed at 900°C.

Uncoupling of the hill reaction from photophosphorylation by anions

The rate of reduction of oxidants by illuminated chloroplasts is greatly stimulated by the presence of high concentrations of many anions. This stimulation is associated with, and quantitatively related to, a decrease in the ability of the chloroplasts to phosphorylate adenosine diphosphate. Phosphate, pyrophosphate, arsenate, citrate, lactate, malonate, and malate are particularly effective in uncoupling electron transport from phosphorylation. Acetate and butryate uncouple but also produce rapidly increasing inhibitions. Oxalate, tartrate, and bicarbonate are intermediate uncouplers. Sulfate and chloride are themselves feeble uncouplers but interact in a complex fashion with other anions, sometimes causing thereby large rate increases. The dependence of various chloroplast preparations on ferric oxalate, chloride ions, or CO 2 should be reconsidered in the light of these general anion effects. Zwitter ions in the form of neutral amino acids uncouple only very slightly and then only at the highest concentrations. In order to reduce anion uncoupling to a minimum, we have prepared a neutral amino acid with appropriate dissociation constants to serve as a buffer for chloroplast reactions. Reacting tris(hydroxymethyl)aminomethane with monochloroacetic acid gave tris(hydroxymethyl)methylglycine, p K's 7.95 and about 2.3 at 25 °C. This substance is much less inhibitory at high concentrations than is the parent tris(hydroxymethyl)aminomethane. It also produces negligible uncoupling at any concentration up to 0.05 molar.

TRYPTAMINES, CARBOLINES, AND RELATED COMPOUNDS: PART IX. THE CYCLIZATION OF SOME NITRO- AND AZIDO-PHENYLPYRIDINES. PYRIDO[1,2-b]INDAZOLE

Heating 2-o-nitrophenylpyridine with ferrous oxalate gives rise to pyrido[1,2-b]indazole (III). The evidence for the structure of this compound is discussed. Similarly, heating 2-o-nitrophenylpyridine methiodide and N-oxide with ferrous oxalate gives (III), in each case, demethylation and deoxygenation preceding the cyclization. In the latter case a minute amount of δ-carboline is also formed. Heating pyridine-N-oxides with ferrous oxalate is a potentially general method of effecting deoxygenations of these compounds. Contrary to the results of Smith and Boyer (11), it is found that heating 2-o-azidophenylpyridine also gives rise to (III). On the other hand, the action of heat on 2-o-azidophenyIpyridine-N-oxide gives a mixture of δ-carboline and δ-carboline-py-N-oxide in low yield. The mechanism of the cyclization of the azides and of the reaction taking place on heating nitro-compounds with ferrous oxalate is discussed briefly; the formation of a nitrene intermediate is favored.The catalytic reduction of 2-o-nitrophenylpyridine-N-oxide giving rise to the azoxy-, azo-, and hydrazo-derivatives is described and the ultraviolet absorption spectra of these compounds are discussed. It is concluded the steric inhibition of coplanarity exists in the azoxy- and azo-compounds leading to the lack of effective conjugation across the N=N bond.

Radiolysis of Crystalline Oxalato Complexes

Several crystalline metal oxalato complexes were irradiated with Co/sup 6//sup 0/ gamma rays. Oxalate ions such as in sodium oxalate and ferrous oxalate were found to be very stable to gamma radiation, compared with those in metal oxalato complexes. Oxalate ions with large covalent character are decomposed more easily by gamma radiation. The much larger G values of Fe/sup 3//sup +/ and Co/sup 3//sup +/ complexs than those of Al/sup 3//sup +/ are related to the reduction of metal ions. Chromium is stable in the Cr/sup 3//sup +/ and Cr/sup 6/ /sup +/ states but unstable as Cr/sup 2//sup +/. (P.C.H.)

Stimulation of the Hill reaction by carbon dioxide

Hill reactions (i.e., ?2 evolution by illuminated chloroplast preparations) are generally assumed to represent the photochemical splitting of water. For about 20 years the view has prevailed that, in the course of a Hill reaction, photolysis generates an 02 precursor and a reductant which is capable of reacting directly or indirectly with any of a variety of oxidants. The metabolism of both photolysis products (oxidant & reductant) evidently is enzymatically controlled. The list of oxidizing agents effective in the Hill reaction began chronologically with ferric oxalate and now includes an impressive number of naturally-occurring as well as exotic substances. On the assumption that oxygen evolution and oxidant reduction are separate if not independent processes, there is no compelling a priori reason to believe CO2 is uniquely involved in the Hill reaction even in a catalytic capacity. However, because of the close analogy between photosynthesis and the various types of Hill reactions, the possible role of carbon dioxide in chloroplast reactions continues to be a subject of concern both theoretically and experimentally, especially so because several reports in the literature suggest that CO2 at least in some instances may have a catalytic effect on reaction sequences which involve water photolysis. Franck (7) found an influence of CO2 on the evolution of 02 by chloroplasts prepared from tobacco leaf. He studied a Molisch-type reaction in which no Hill oxidant was added to the preparations. Only small amounts of 02 were evolved but the rate was significantly higher when CO, was present. Brown and Franck (3) using C1402 found that carbon 14 was not taken up under the conditions of these experiments. They concluded that CO, could play only a catalytic role. Kessler (9, 10) observed that the rate of reduction of nitrite by illuminated Ankistrodesmus cells as measured by H2 uptake was increased in the presence of catalytic amounts of CO2. Experiments performed with C1402 showed that the reduction of nitrite with hydrogen was not accompanied by an appreciable fixation of carbon. Thus the effect of CO2 apparently was indirect. Boyle (2) reported manometric experiments from which he claimed at least small quantities of carbon dioxide were required for 02 evolution in the light using triturated spinach leaves. These experiments were repeated by Clendenning and Gorham (6) who found no differences in Hill reaction rate between vessels which contained carbon dioxide and those which did not. Because Boyle's results were not confirmed and besides were incompatible with prevailing theory they have generally been ignored. Warburg and Krippahl (11, 12) using kohlrabi chloroplast preparations with quinone as the oxidant reported that small amounts of CO. increased the rate of the Hill reaction. Similar effects were noted with frozen-dried Chlorella and with quinone-poisoned whole Chlorella cells. Such results are of course reminiscent of the earlier observations by Boyle, even though the experimental material and nmethods were different. It is patently desirable to verify the claim that CO2 can augment the Hill reaction using experimental methods which adhere closely to those of Boyle and of Warburg and Krippahl. We report here the results of such attempts at confirmation. It was found possible to obtain manometric measuremiients which were in all respects identical with those reported by Boyle although, as will be shown, these results do not support his interpretation that there was a CO2 effect on the Hill reaction. Manometric results also were obtained which were at least qualitatively similar to the findings of Warburg and Krippahl with kohlrabi chloroplasts. The reactions in which an apparently valid CO2 effect could be observed also were measured by mass spectrometry which has the important advantage over manometry of relatively unambiguous analytic specificity. Additional experiments were performed with tracer CO, and with tracer 02 which permitted the detection and measurement of simultaneous production and consumption of these gases thus providing detailed information of the nature of the CO, effect. This method could reveal the operation of a cyclic regeneration of CO. by illuminated kohlrabi chloroplast preparations.

The formation of a nitrene intermediate in the reaction of nitro compounds with ferrous oxalate

The formation of a nitrene intermediate in the reaction of nitro compounds with ferrous oxalate

Syntheses of heterocyclic compounds—I : Cyclization of N-substituted O-nitroanilines

Internal cyclization of a nitrogroup was carried out by heating the N-substituted o-nitroanilines (I; RC 6H 11, C 6H 5.CH 2, C 6H 5.CH 2.CH 2, XNH) in the presence of ferrous oxalate 1 (Waterman and Vivian's method) as a potential route to partly hydrogenated nitrogen heterocycles. A mechanism for this type of ring-closure is proposed.

Inorganic complexes in volumetric analysis — Part II Use of ferric phosphate complex in the estimation of iodide

The decomposition of ferric oxalate complex under varying concentrations of iodide, acid and oxalate has been studied and has been used in the estimation of iodide. Iodine is quantitatively liberated from iodide in acid solution by dichromate used in excess, which is then reduced by ferrous ammonium sulphate, also used in excess. The ferric iron formed in solution is complexed with oxalate ions and hence does not interfere with the titration of the liberated iodine against standard sodium thiosulphate. Oxalate ions also catalyse the chromic acid-hydriodic acid reaction which is slow at low concentrations of dichromate and iodide. This method has been successfully applied for the estimation of iodide in iodized salt.