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Item Diffusion in Crystalline Hexamethyldisilane(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Saltmouse, Peter W; Sherwood, John NAn examination has been made of plastic deformation and of diffusion of hexamethylethane-14C in the highly plastic phase of hexamethyldisilane. The results are consistent with most previous studies of this type of material.Item Belousov-Zhabotinskii Oscillating Reaction in Solutions containing Gallic Acid(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Babu, J. Sreekantha; Srinivasulu, KChemical oscillations are observed in a Belousov–Zhabotinskii type reaction using gallic acid rather than malonic acid.Item Activation Enthalpy of Diffusion for Iodine in Mixed Solvents(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Nakanishi, Koichiro; Nishimoto, YasunobuThe diffusion coefficients of iodine diluted in two different binary mixed solvents have been measured as a function of temperature. The enthalpy of activation of diffusion was evaluated from the Arrhenius plot of the data in cyclohexane + ethanol and +iso-octane solutions. The enthalpy value for iodine in an equimolar mixture of cyclohexane + ethanol was found to be ∼1 kcal mol–1 larger than that for iodine in the two pure solvents.Item Closed Capillary Method for Tracer Diffusion Measurements in Liquids(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Passiniemi, Pentti; Liukkonen, Simo; Noszticzius, ZoltanA continuous closed capillary method is described in which the lower half of the capillary is filled at the beginning of the experiment with radioactive solution and the upper half with inactive solution. Measurement of any change in the activity is based on the position dependent counting efficiency of the nuclear detector system. It has been shown that convection disturbances arising in the filling process present no difficulties to use of this method. The tracer diffusion coefficient of 22NaCl has been determined in 0.1 and 1.44 mol dm–3 aqueous sodium chloride solutions at 298.15 K. The results agree with the corresponding open-ended capillary and diaphragm-cell values of other authors. An average precision of 0.4 % was attained in the measurements. The systematic errors of the open-ended capillary method, the ΔL-effect and the immersion effect, are eliminated in closed capillaries. Also, in contrast to the two other methods, no calibration is required.Item Heterogeneous Catalysis in Solution Part 15.1—Theoretical Treatment of Parallel First-Order Catalysed and Uncatalysed Reactions(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Spiro, MichaelA general treatment is presented of first-order or pseudo-first-order reactions proceeding both homogeneously in solution or the gas phase and heterogeneously on a catalytic surface. Rapid adsorption and desorption are assumed for both reactant and product, and equations are derived for Henry, Langmuir and Freundlich adsorption of both species. Interconversions of kinetically identical species, reactions proceeding to completion and purely heterogeneous processes emerge as special cases, and the relationship to enzyme kinetics is pointed out. Methods are suggested for fitting the theory to experimental kinetic data.Item Adsorption and Oxidation of Dimethylaniline by Laponite(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Vansant, Etienne F; Yariv, ShmuelColoration of synthetic Laponite by dimethylaniline was studied in relation to the adsorption data, and to different reaction conditions including the nature of the exchangeable cations, the pH and the concentration. Using visible and i.r. spectra, together with X-ray patterns, the colour reaction mechanism was investigated. The coloration could be ascribed to the following stages: (1) sorption of dimethyl-aniline, (2) oxidation by atmospheric oxygen into N,N-dimethyl-N′-methylbenzidine and bis-p(N,N-dimethylaminophenyl)-p(N′-methylaminophenyl)methane and (3) further oxidation to a blue quinoid cation or its protonated yellow component and to methyl violet, respectively.Item Charge Density Effects in Ion Exchange Pari 1.—Heterovalcnt Exchange Equilibria(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Maes, Andre; Cremers, AdrienA thermodynamic study is made of the Na–Ca heterovalent exchange reaction in 4 montmorillonite clay minerals with complete octahedral isomorphic layer charge but varying in charge density (Otay, three Camp Berteau samples which are 0, 25 and 40 % reduced in charge by the Hofmann–Klemen effect). The free energy of exchange decreases linearly with the logarithm of the charge density, as predicted from double layer calculations. The endothermicity of the reaction almost balances the entropy, both of them decreasing in magnitude as the charge density decreases. Interlamellar hydration changes, correlated with d001 spacing measurements, can explain the observed effects.Item Solvation Spectra Part 54.1—A Low Temperature Infrared Spectroscopic Study of the Solvation of Ions in Methanol(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Strauss, Imants M; Symons, Martyn C. RBroad featureless bands in the O—H stretching region for CH3OH in CH3OD containing a range of 1:1 electrolytes become narrower on cooling below the glass point and usually display several features. Lithium and sodium salts up to ∼3 mol kg–1 show narrow bands on the high-frequency side of the bulk methanol band that are assigned to solvent molecules bonded to the anions. The bulk methanol bands are broadened and shifted by the cations, but separate bands for the cation solvates are not resolved. At higher concentrations of salt, the anion bands are also shifted by the cations to give new high frequency bands assigned to solvent shared ion-pairs. Tetra-alkyl-ammonium salts in the 1 mol kg–1 region give new bands characteristic of the anions only. Sodium tetraphenylboron gives a narrow component at 3520 cm–1 and a very broad component centred at ∼3360 cm–1. The former is assigned to two O—H groups bonded to a single methanolic oxygen atom: the latter is assigned to oscillators in short chains or cyclic structures. A broad band at ∼3360 cm–1 for other concentrated electrolyte solutions is assigned similarly.Item Mass Spectrometric Study of the Thermal Decomposition of 1,3,5-Trinitrohexahydro-l ,3,5-triazine (RDX)(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Bradley, John N; Butler, Alan K; Capey, William D; Gilbert, James RThe thermal decomposition of RDX has been studied over the temperature range 130–230°C under free molecular flow conditions which allow reactions in the gas phase and reactions in the condensed phase to be clearly distinguished. Analysis by quadrupole mass spectrometry has revealed the participation of four separate mechanisms. Two of these involve isolated RDX molecules and take place either by stripping of HNO2 and NO2 groups leaving the ring intact (low temperature) or by ring breaking with elimination of CH2O (high temperature).Item Transport in Aqueous Solutions of Group IIB Metal Salts at 298.15 K Part 2.—Interpretation and Prediction of Transport in Dilute Solutions of Cadmium Iodide : An Irreversible Thermodynamic Analysis(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Paterson, Russell; Anderson, John; Anderson, Stephen S; LutfullahThe transport data of Part 1 have been used to obtain the binary mobility coefficients (Lik) and corresponding resistance coefficients (Rik) of the salt in the range 0.05–0.60 mol dm–3. It is shown that these binary mobility coefficients are summations of the more fundamental mobility and coupling coefficients (lik) between the component ions of the complexed salt: Cd2+, CdI2–xx(x= 1, 2, 3, 4) and I–. The distribution of these complexes at each concentration have been obtained from stability constant data and used in an optimisation procedure to obtain equivalent ionic conductances of the complex ions at infinite dilution (λ°x). These data were used to estimate lik coefficients (using Pikal's method), to predict binary coefficients (Lik) and to predict the transport numbers, conductances and salt diffusion coefficients of the salt in dilute solutions. Predicted and observed data are in good agreement in dilute solutions.