James C. Fanning

The chemical reduction of nitrate in aqueous solution

Abstract The nitrate ion has high chemical stability, especially at low concentrations. Standard reduction potentials indicate that it should serve as an excellent oxidizing agent, but in order to react with suitable reducing agents to form elemental nitrogen or ammonia, special conditions, such as catalysts and high temperature and pressure, are required. A review of the literature on the chemical reduction of nitrate in aqueous systems has found about a hundred articles dealing with nitrate removal from such systems, with the majority having been published over the last decade. The reducing agents which have been examined to the greatest extent for acidic solution are formic acid, iron metal, methanol and the ammonium ion; while for basic solution aluminum, zinc and iron metals, iron(II), ammonia, hydrazine, glucose and hydrogen have been studied.

Some transition metal complexes of 8-aminoquinoline

Abstract The reaction of 8-aminoquinoline with chromium (III), manganese (II), iron (II) and (III), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and platinum(II) salts has been studied. In many instances definite compounds were prepared. Magnetic moments, molar conductances, infra-red, visible and ultra-violet spectra were measured for some of these compounds. 8-Aminoquinoline was found to be very susceptible to oxidation in the presence of certain metal ions.

The solubilities of the alkali metal salts and the precipitation of Cs+ from aqueous solution

Abstract Radioactive 137Cs may be removed from nuclear waste aqueous solutions by precipitation. Alkali metal salt solubility trends show that the Cs+ salts have the largest range of solubilities for all of the alkali metal salts and that Cs+ should be the most likely ion of the group to form a precipitate in solution. The tetraphenylborate anion (B(C5H5)4−, TPB) precipitates Cs+ as the insoluble CsTPB. However, there are a number of problems associated with this compound and another precipitating agent is needed. A potential substitute is the cobalt dicarbollide anion (Co(B9C2H11)2−, CDC) which forms a slightly more soluble compound, CsCDC. The anion:cation volume ratios for several simple alkali metal salts, when compared with their solubility values, indicate that forces within the solid crystal control solubility. Similar comparisons for the TPB and CDC anions indicate that the solubilities are controlled by the hydrophobic nature of the anion. Some requirements are proposed for an anion to form a precipitate with Cs+.

Comparative crystal structure examination of some iron(III) quadridentate schiff base complexes

Abstract The crystal structures of four iron(III) N,N′-ethylenebis(acetylacetonylideneimine), Fe(acacen)+, complexes, [Fe(acacen)NO3] (1), [Fe(acacen)C1] (2), K[Fe(acacen)(CN)2]· 2H2O (3) and [Fe(acacen)]2O· CH2Cl2 (4), were determined. In 1 the nitrate is bound to the iron in a symmetrical bidentate manner producing a distorted acacen. The iron in 2 is bound to an axial C1 and is 0.54 A out of the N2O2 chelate atom plane. In 3 two CN ligands are axially bound to the iron above and below the near planar N2O2 chelate group. Two independent dimers were found in the unit cell of 4 with the two Fe(acacen)+ groups in each dimer differing significantly in bond angles, but not in bond distances. Comparisons were made of the coordination sphere bond distances and angles of the Fe(acacen)+ complexes with literature values of some iron(III) N,N′-ethylene-bis (salicylideneimine), Fe(salen)+, complexes. Low-spin K[Fe(salen)(CN)2]· 0.5H2O(5)was prepared in order to compare its properties with those of the intermediate spin compound 3.

The reduction of nitrate and nitrite ions in basic solution with sodium borohydride in the presence of copper(II) ions

The reaction of NaNO3 and NaBH4 with added Cu(OH)2 in 1 M NaOH at 65°C under Ar rapidly produced NH3, Cu metal, and H2 with NO2 formed as an intermediate. The overall equation describing the reaction is: Cu(OH)23NO3 7BH4 20H2OiCu3NH37B(OH)4 15H2 3OH A direct reaction of NaNO2 with NaBH4 under the same conditions as those used with NaNO3 follows the equation: Cu(OH)2NO2 2BH4 5H2OiCu4H2NH3 2B(OH)4 OH The reductions of nitrate and nitrite with NaBH4 did not take place in basic solution unless Cu(OH)2 was present.

Prussian blues from the thermal decomposition of H4Fe(CN)6 and H3Fe(CN)6

Abstract Solid H 3 Fe(CN) 6 and H 4 Fe(CN) 6 were heated at constant temperature in nitrogen, oxygen, and hydrogen. In these atmospheres, Prussian Blue type materials were formed at temperatures of 160° or less. The materials were characterized by chemical analysis, i.r. spectra, Mo¨ssbauer spectra, X-ray powder diffraction patterns, and magnetic susceptibility measurements. The products were reacted with water vapor, ammonia, and hydrogen chloride and approximately two moles of each gas per mole of iron were added. H 4 Fe(CN) 6 was heated at 63·0° in moist oxygen and the decomposition followed by weight changes and by changes in the magnetic susceptibility. The steps of the Prussian Blue formation under these conditions are proposed.

SOME METAL COMPLEXES OF α, β, γ, δ-TETRA-(4-PYRIDYL) PORPHINE

Abstract The zinc (II), copper (II), nickel (II), cobalt (II), chloromanganese (III), and chloroiron (III) complexes of α, β, γ, δ-tetra-(4-pyridyl)-porphine (4-TPyP) were prepared. The magnetic susceptibilities from near 0° to 90° K and at room temperature were measured for solid Cu(4-TPyp), Ni(4-TPyP), Co-(4-TPyP), ClMn(4-TPyP) · H2 O and ClFe(4-TPyP). The Mossbauer spectra of ClFe(4-TPyP) were obtained at several temperatures. The infrared spectra and d-spacings were obtained for all of the solids. Electronic spectra of the complexes in pyridine and, where possible, in 0.1 N HCl solution were recorded. Evidence of intermolecular interaction was found for Co(4-TPyP), Ni(4-TPyP), and ClFe(4-TPyP).

Iron(III) nitrate complexes with linear pentacoordinate ligands and their base hydrolysis products

Abstract The complexes, Fe(saldpt)NO3, [Fe(salmedpt)]2(NO3)(OH), Fe(saldien)NO3, and Fe(salmedien)NO3·CH2Cl2, have been prepared. Solid state properties (IR spectra, Mossbauer spectra and magnetic moments) and solution properties (electronic spectra, PMR spectra, conductivities and cyclic voltammograms) have been measured. The saldpt and saldien compounds when reacted with aqueous KOH formed Fe(saldpt)sal and Fe(saldien)OC2H5·H2O. Single crystals of Fe(saldpt)sal were prepared and examined. Crystal data: Fe(saldpt)sal: monoclinic, space group P21/c(#14), a=12.486(5), b=18.502(8), c=10.870(5) A, β=104.23(3)°, V=2434(2) A3, Z=4, Dc=1.40 g cm−3, R=0.0473 (Rw=0.0681) for 317 parameters and 2107 data with Fo2 > 3σ(Fo2).

The reaction of amines with N,N′-ethylenebis(salicylideneiminato)(nitrato)-iron(III) and related complexes

Abstract The title compound, Fe(salen)NO 3 , was reacted with imidazole, 1-methylimidazole, piperidine, and morpholine in either chloroform or dichloromethane solution. The reactions were monitored with proton NMR and electronic spectra and conductance measurements. The imidazole bases appeared to react with the complex in a 2:1 fashion with displacement of the nitrate, producing a high-spin iron(III) complex. The secondary amines promoted hydrolysis with any trace water present to form [Fe(salen)] 2 O. The chloro complex, Fe(salen)Cl, did not react with the imidazole bases, but did form the μ-oxo complex when a large excess of piperidine was present. The N,N′-phenylenebis-(salicylideneimine) complex, Fe-(salphen)NO 3 , was found to precipitate from an imidazole (im) chloroform solution as the high-spin complex, Fe(salphen)NO 3 ·2im.

Caesium cobalt dicarbollide—solubility, precipitation and reactivity in basic aqueous solution

Abstract The title compound, Cs+[Co((3)-1,2-C2B9H11)2]− (CsCDC), was precipitated with a NaCDC solution from solutions containing CsCl. The reaction was followed by measuring the loss of light intensity as the precipitate formed. [Cs+] and [CDC−] at the point of precipitation were estimated and approximate values of Ksp for CsCDC were determined at room temperature: 8 × 10−6 (water), 7 × 10−6 (1 M NaOH) and 2 × 10−6 (5M NaCl/0.1 M KOH/1.0 M NaOH). In some cases, NaCDC precipitated from solution when added to the latter salt solution. For the medium, 5 M NaNO3/0.1 M KOH/1.0 M NaOH, a four-fold excess of NaCDC was added to a 10 mM Cs+ solution at 40°C and the [CDC−] measured spectrophotometrically. Only CsCDC precipitated, and a Ksp of 3.9 × 10−6 was determined. The solubilities of CsCDC were measured in NaNO3 and NaCl solutions at 30°C as a function of the Na salt concentration. The reaction of the CDC− with OH− slowly produces B(OH)4−, H2 and CoO(OH). The reaction of 22 μM CsCDC 173 with NaOH (1 M) has a first-order rate constant at 56°C of 8.8 × 10−7 s−1, while that for NaCDC (14 mM) is 7.2 × 10−7 s−1. The activation energy for the reaction is 110 kJ mol−1.