Cyanide In Aqueous Solution Research Articles

Photolysis of sodium cyanide in aqueous solution

The initial quantum yields Q i obtain by indirect photolysis of dilute aqueous alkaline solutions of CN − ions at 184.9 nm are Q i(NH 3= 0.27, Q i(HCHO) = 0.07, Q i(HCOO − = 0.10 and Q i(−CN − = 0.29 although CO 2 was also formed, its quantum yield was not determined. Based on these results, and by means of computer simulations, it was possible to postulate a probable reaction mechanism. In addition, the concentration changes of the transients, and the final products were calculated as functions of time.

The cyanobis(1,10-phenanthroline)platinum(II) complex in aqueous solution and as the crystalline nitrate. Nuclear magnetic resonance measurements and crystal-structure determination

The bis(1,10-phenanthroline)platinum(II) cation rapidly adds cyanide in aqueous solution forming the cyanobis-(1,10-phenanthroline)platinum(II) ion, which from 13C n.m.r. spectra has been shown to contain five-co-ordinated platinum both in water and in nitromethane solution. The crystals of cyanobis(1,10-phenanthroline)platinum(II) nitrate are triclinic, space group P, with Z= 2 and unit-cell dimensions a= 15.616(11), b= 7.264(6), c= 10.564(7)A, α= 102.81(4), β= 80.90(4), and γ= 96.47(4)°. The structure has been determined by the heavy-atom method from diffractometer data and refined to R= 0.031 for 3 562 independent reflections. Three nitrogen atoms from the phenanthroline groups and the carbon atom from the cyanide form an approximately square-planar configuration about the platinum; Pt–N(1) 2.062(5), Pt–N(2) 2.007(5), Pt–N(3) 2.053(5), and Pt–C(25) 1.931(6)A. The remaining nitrogen atom of the phenanthroline groups is at the apex of a square pyramid, Pt–N(4) 2.761 (5)A. In aqueous solution OH– and SH– appear to react analogously with the bis(1,10-phenanthroline)-platinum(II) ion. The cyano-complex is stable in solution and reacts only slowly with other nucleophiles (e.g. excess of CN–, OH–, and halide ions).

Solvent Extraction Study of Mercury(II) with Zolon Red (HZR)

Abstract Zolon Red, Mercury(II) The extraction of mercury(II) from the aqueous solutions of mercury(II) nitrate and mercury(II) chloride with zolon red (HZR) dissolved in w-butanol has been studied. The extraction of mercury (II) from the aqueous nitrate system has been found to be much better compared to that from the aqueous chloride system in the pH range of 1 to 6. The extraction of mercury with zolon red is simple, fast and selective. The composition of the extracted mercury zolon red compound has also been studied. Regeneration of the extracting solution of zolon red is readily achieved by stripping the mercury(II) with an aqueous cyanide solution.

Structure and motion in water. Analysis of vibrational and rotational dynamics of cyanide ion in aqueous solution from infrared and Raman bandshapes

Infrared and Raman spectra of the CN stretching vibration of potassium cyanide in aqueous solutions have been recorded. Experimental infrared and anisotropic Raman bandshapes are found to be much more broad than the corresponding isotropic Raman profile and give evidence for a large rotational motion of the CN– ion in aqueous solution. Changes in these bandshapes with respect to temperature confirm the existence of an orientational contribution.Spectral profiles are analysed using the theory of Bratos et al., which allows the separation of vibrational and rotational components. From results obtained by changing the temperature, the pressure and the concentration, and by isotopic solvent exchange from H2O/D2O, one may conclude that, in the bandshapes, the vibrational part reflects a phase relaxation due to fluctuations in the anion environment. The theoretical result of the convolution of the isotropic Raman band by a rotational profile derived from a suitable model is compared with all the experimental results. It is shown that in aqueous solutions, the CN– ion executes “instantaneous” rotations through large angles moving between sites of optimal interaction with the surrounding molecules of water. The rest time at the optimal sites is about 1 ps.The activation energy of this reorientational motion is high (3 kcal mol–1) and must be related to the energy needed to break a weak hydrogen bond between the anion and the water molecules.The results are compared with previous thermodynamic and spectroscopic data which also show the “structure breaking” properties of the cyanide anion.

Infrared spectral characterization of peptidic material produced by ionizing radiation in aqueous cyanides.

Oligomers formed by ionizing radiation in aqueous cyanide solutions, under various experimental conditions, have been characterized by infrared spectroscopy. IR bands appear in the region known to be characteristic for amides and peptides. The results are discussed in relation to radiation-induced formation of peptidic material and the potential role of ionizing radiation as an energy source for some processes in prebiotic molecular evolution.

Spectrophotometric Determination of Cyanide in Biological Materials

Abstract The analytical methods currently used for the determination of cyanide in biological materials are the aeration method with the Prussian blue (ferricyanide) reaction [1] and some microdiffusion methods [2,3]. The methods are dependent on color reactions, the procedures are either time-consuming or cumbersome, and the results are of questionable accuracy. A method using the ultraviolet light absorption characteristics of a cyanonickelate complex was developed by Scoggins [4] for the accurate identification and quantitation of cyanide in aqueous solution. This method was found to be readily adaptable for the determination of cyanide in biofluids and tissues. The resulting cyanide-nickel complex which formed rapidly was found to be stable and could be quantitated readily. This paper presents a method to detect cyanide in biological materials by a spectrophotometric procedure.

Equilibria in complexes ofN-heterocyclic molecules, Part XV+. Intermediates in the reaction of cyanide with transition metal tris complexes of 1,10-phenanthroline, 5-nitro-1,10-phenanthroline and 2,2'-bipyridyl

The Ru(phen)3(CN)2 · 6 H2O, Ru(bipy)3(CN)2 · 6H2O, Fe(phen)3(CN)2 · H2O and Ru(5-NO2P)3(CN)2 · 2 H2O compounds have been isolated during the reaction of the parent cations with aqueous cyanide solutions. It is evident, that in each case, attack at the ligand has taken placevia the cyanide nucleophile, though the equilibrium constant for the formation of the Reissert-type species are widely different. The implications of the findings with respect to the known reaction kinetics of the parent ions in aqueous cyanide solution are discussed.

The reaction of heteroaromatic N-oxide with acid chloride and cyanide. II. On the reaction of 2,4-disubstituted quinoline 1-oxide with benzoyl chloride and potassium cyanide (author's transl)

Reaction of quinoline 1-oxides having substituents in 2- and 4-positions with benzoyl chloride and potassium cyanide in aqueous solution was attempted. The N-oxides used were 2, 4-dimethyl-(Ia), 4-methyl-2-phenyl-(Ib), and 2-methyl-4-phenyl-quinoline 1-oxide (Ic), methyl 1, 2, 3, 4-tetrahydro-9-acridinecarboxylate 10-oxide (Id), and methyl 2-ethyl-3-methyl-4-quinolinecarboxylate 1-oxide (Ie). Results of the reaction were as follows : 1) Ia and Ie afforded 1, 2, 3, 4-tetrahydroquinoline derivatives; 3-benzoyloxy-4-methyl-2-methylene-1, 2, 3, 4-tetrahydroquinoline-4-carbonitrile (IIa) from Ia and methyl 3-benzoyloxy-4-carbamoyl-2-ethyl-2-hydroxy-3-methyl-1, 2, 3, 4-tetrahydroquinoline-4-carboxylate (IIe) from Ie. 2) A product (III) in which a benzoyloxy group was introduced into the α-carbon in the side-chain at 2-position of the quinoline ring, accompanied with liberation of oxygen from the N→O group, was formed; IIId in a good yield from Id and IIIa from Ia. 3) Similar product with introduction of a benzoyloxy group into the quinoline ring, accompanied with liberation of oxygen from the N-O group, was formed; 6-substituted compound (IVa, b) from Ia, 3- and 8-substituted compounds (IVb, 3 and IVb, 8) from Ib, 3- and 8-substituted compounds (IVc, 3 and IVc, 8) from Ic, and 8-substituted compound (IVb, 8) from Ie.

Quinone—cyanide reactions: their use for the determination of quinones and cyanide

Both quinones and cyanide can be determined in the μg—ng ml -1 range by measuring the fluorescence of the addition products produced. The yield is low (except for the 2-sulfonic acid of 1,4-naphthoquinone) in aqueous solution and 1:1 DMSO:water is the recommended medium for determinations of quinones. The 2-sulfonic acid of 1,4-naphthoquinone permits the determination of trace amounts of cyanide in aqueous solution; there are few interferences.

Possible pathway for prebiotic uracil synthesis by photodehydrogenation.

THE synthesis of purines in potentially prebiotic conditions has been demonstrated1,2. Adenine and guanine have been synthesised directly from aqueous cyanide solutions and a mechanism for the concentration of hydrogen cyanide in low melting eutectics has been proposed3. These purines are also obtained from solutions of cyanogen (unpublished). The pyrimidines, however, have provided a more difficult problem. Uracil has been obtained from malic acid and urea, but only by heating in the presence of concentrated sulphuric acid4 or polyphosphoric acid5. Low yields of uracil have been inferred from spectral data for a reaction involving acrylonitrile, urea and ammonium chloride6. Further details concerning the conditions of this reaction, however, have not been offered. Cytosine and, indirectly uracil, have been prepared from cyanoacetylene and cyanate7,8. The rapid hydrolysis of these reactants raises doubts about this route. Cyanoacetaldehyde, a hydrolysis product of cyanoacetylene, condenses with guanidine in aqueous solution to yield 2,4-diaminopyrimidine, which is hydrolysed to cytosine and uracil. The later route is considered to be more plausible9. Thymine has been prepared in 0.1% yield from uracil by a hydroxymethylation-reduction sequence involving formaldehyde and hydrazine hydrate in ammoniacal solution10. In view of uncertainties concerning the abundances on the primitive Earth of a number of the precursors which have been used in these studies, it seemed desirable to consider alternative routes to the synthesis of pyrimidines. In this report we describe the synthesis of uracil by the photodehydrogenation of 5,6-dihydrouracil (DHU), as well as the synthesis of DHU from β-alanine and urea in mild conditions.

Pulse radiolysis of aqueous cyanide solutions. Kinetics of the transient hydroxyl radical and hydrogen atom adducts and subsequent rearrangements

Pulse radiolysis of aqueous cyanide solutions. Kinetics of the transient hydroxyl radical and hydrogen atom adducts and subsequent rearrangements

A New Spectrophotometry Determination of Cyanide by Solvent Extraction as Tris-(1,10-Phenanthroline)-Iron (II)-Thiocymate

Abstract By shaking aqueous cyanide solution with nitrobenzene contained sulfur, thiocyanate is formed and is extracted into the nitrobenzene as an ion pair of thiocyanate anion and tris-(1,10-phenanthroline)-iron(II) chelate cation. By measuring the color intensity of the organic phase at 516 nm, cyanide is determined spectrophotometrically. A linear calibration curve is obtained up to 4 × 10−5M of cyanide in the aqueous phase.

Possible role of hydrogen cyanide in chemical evolution: Investigation of the proposed direct synthesis of peptides from hydrogen cyanide

The compounds formed upon oligomerization of cyanide in aqueous solution have been separated into acidic, basic, amphoteric and neutral fractions. Urea is the major constituent of the neutral fraction and oxalic acid is present in the acidic fraction. The oligomerization mixtures isolated in the acid, basic and amphoteric fractions consist of low molecular weight substances which yield amino acids on acid hydrolysis. Citrulline has been identified as a major amino acid released on acid hydrolysis of the product mixture. No amino acids are released from the oligomerization mixture by pronase or carboxypeptidase A. This catalyzed hydrolysis demonstrates that this system does not contain compounds with peptide links. The oligomerization products are susceptible to oxidizing agents but are affected little by reducing agents.

Kinetics of reaction of tris(2,2′-bipyridyl)iron(II) with cyanide in aqueous solution

The kinetics of the reaction between the tris(2,2′-bipyridyl)iron(II) cation and cyanide ion have been investigated, and activation parameters for this reaction determined.

Determination of free cyanide in aqueous solution in presence of complex cyano anions

Determination of free cyanide in aqueous solution in presence of complex cyano anions

Kinetics of reaction of substituted tris-(1,10-phenanthroline)iron(II) complexes with cyanide

The kinetics of reaction of a series of substituted tris-(1,10-phenanthroline)iron(II) complexes with cyanide in aqueous solution and in 50% (v/v) aqueous ethanol have been investigated. For all the complexes studied the mechanism is predominantly associative in character. Second-order rate constants for reaction with cyanide vary in the expected manner with the nature of the ligand substituents; these rate constants correlate with the respective second-order rate constants for hydroxide attack.

Raman study of complexing by halide of mercury (II) cyanide in aqueous solution

Raman spectra of aqueous solutions of Hg(CN) 2 in the presence of halide ions indicate complex formation. The three Raman lines of Hg(CN) 2 are shifted or broadened and new lines appear which are attributed to Hgz.sbnd;CN bending and HgN stretching, where X = Br and I.

The use of diphenylcarbazone for the determination of microgram amounts of lead.

The conditions necessary for extracting the crimson diphenylcarbazone-lead complex into xylene from an aqueous cyanide solution have been examined. A procedure is described for the spectrophotometric determination of lead isolated by means of diphenylthiocarbazone.

1312. The kinetics of the reactions between the methyl halides and potassium cyanide in aqueous solution

1312. The kinetics of the reactions between the methyl halides and potassium cyanide in aqueous solution

529. The kinetics of the reaction between methyl iodide and potassium cyanide in aqueous solution

529. The kinetics of the reaction between methyl iodide and potassium cyanide in aqueous solution