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The mass spectrometry of alkyl nitrites and alkyl nitrates with chemical ionization using methane and isobutane as reagent gases produces quasi-molecular ions, (M+1)+ and/or (M−1)+. These ions have maximum abundance for lower nitrates and nitrites. The chemical ionization mass spectrometry, in conjunction with gas chromatography, can be used for quantitative estimation of alkyl nitrates and nitrites in very low amounts.

1-(p-Dimethylaminophenylazo)-2-naphthol-3,6-disulfonic acid is formed in many important commercial “dry process” diazo-printing. Some physico-chemical properties of this dye in solutions have been investigated. Its absorption spectra in various solvents and in water at various acidities have been discussed on the basis of azoquinone hydrazone tautomeric and acid-base equilibria respectively. The dissociation constants of the acid-base equilibria in the pH range of 1–14 in aqueous solutions have been determined at 25 °C and 1.0 M ionic strength. Conductivities of aqueous solutions at various concentrations and temperatures have been interpreted on the basis of the colloidal nature of the dye. The polarograms of the compound have been drawn at various pH’s and discussed. Polarographic method indicates complex formation between Zn(II) salt and the dye in the mole ratio of 1:2.

The emf of the cell: Ag, AgCl, NaCl(m)⋮Na 2 CrO 4 (m/2), Ag 2 CrO 4 , Ag in water + 10, + 20, + 30, and + 40 mass percent of dioxane has been measured at 5°C intervals over the temperature range 15–45°C. The values of the standard potentials of the silver—silver chromate electrode have been determined in these mixed solvent media at these temperatures. The standard thermodynamic quantities (Δ G °, Δ H °, and Δ S °) for the cell reaction in water + dioxane mixtures have been evaluated at these temperatures. The results are discussed in terms of the preferential solvation of the ions.

The absorption of 2-(substituted phenylazo)-1-naphthol-4-sulfonic acid has been studied in neutral, acidic, and alkaline aqueous solutions as well as in solid state. Assignment of band positions to azo and hydrazone tautomers has been made by calculations using the SCF-CI-MO method. Introduction of electron-donating (or electron-withdrawing) substituent in the diazo part showed bathochromic (or hypsochromic) shift of the absorption band, which was elucidated by the charge migration and the character of the substituents taking into account azo-hydrazone tautomerism. In case of compounds containing electron-donating substituents, aggregation seems to take place in the solid state.

Department of Chemistry, Univ. College of Engineering, Burla-768 018, Orissa Manuscript received 13 November 1979, accepted 20 December 1979 Mono· and diamine adducts of salicylidenaminocarboxylate complexes of nickel (II) have been prepared and analysed by elemental, molar conductance, magnetic moment, infra-red and electronic spectral analyses. The compounds have the compositions NiSA.L2(where L=monoamines like pyridine (Py), \(\propto\)-picoline (\(\propto\)-pic), \(\gamma\)-picoline (\(\gamma\)-pic), quinoline (\(Q\)) and triethylamine (Et3N) and NiSA.L'.nH2O (where L' =ethylenediamine (en). (\(o\)-phenylenediamine (\(o\)-pd), \(o\), \(o\)'-bipyridyl (bp) and \(o\)-phe- nanthroline (\(o\)-pben) with SA--=salicylideneglycinate (Sg--) or salicylideneanthra- nilate (Sa--). All the compounds are found to be dimeric octahedral complexes using a bidentate carboxylic bridge.

Department of Chemistry, University College of Engineering, Burla-768 018 Manuscript received 24 August 1981, revised 22 September 1982, accepted 28 january 1983 Oxovanadium(IV) Complexes of Some Tridentate Dibasic Schiff Bases of ONO Donor Type &nbsp

The dissociation constant of trans-cinnamic acid in water has been determined at 15, 20, 25, 30, 35, 40, and 45 °C using a cell without liquid junction potential. From the temperature coefficient of the dissociation constant, the standard enthalpy, entropy, and free energy changes of the dissociation process have been calculated.

The chemical ionization mass spectrometry of epoxides using methane as a reagent gas produces quasi-molecular ions, (M+1)+. This ion has maximum abundance for most epoxides except 1,2-epoxybutane. The method is useful for determination of the molecular weight of epoxides.

Mass spectrometry by chemical ionization using CH4 and iso-C4H10 is found to be very suitable for identification and quantitative analysis of ethyl nitrate necessary for air-pollution study. It produces protonated molecular ion which is not obtained in the electron impact method.

The e.m.f. of the cell Ag, AgCl(s)| NaCl(m)⋮ NaN3(m)| AgN3(s), Ag in water and water +10, +20, +30 and +40 mass % dioxan has been measured at 5 °C intervals from 5 to 45 °C. The values of the standard potentials of the silver, silver azide electrode have been determined in water and the mixtures at these temperatures. The change in standard thermodynamic quantities (ΔG⊖, ΔH⊖ and ΔS⊖) for the electrode reaction have been evaluated. The thermodynamic parameters for the transfer of HN3 from water to the mixtures have also been evaluated. The results are discussed in terms of the preferential solvation of ions.

Electromotive force measurements on cells without a liquid junction have been used to determine the pK1 and pK2 values, at different temperatures, of DL-malic, maleic and fumaric acids in water and water + 10, + 20, + 30 and + 40 mass percent dioxan. From the temperature coefficients, the thermodynamic quantities ΔG°, ΔH°, ΔS° and ΔC°p of the dissociation processes have been calculated. The results have been discussed with respect to preferential solvation. The distances between the carboxylic groups have been calculated from the ratio of the successive dissociation constants in these media.