Kinetics of oxidation of cuprous chloride by oxygen in aqueous hydrochloric acid solutions

The rates of absorption of oxygen into aqueous cuprous chloride solutions containing hydrochloric acid were measured at 15, 25 and 35°C using a baffled agitated vessel operated batchwise and the experimental results were analyzed with the chemical absorption theory. The reaction between oxygen and cuprous chloride was found to be second order, i.e. first order with respect to oxygen and CuCl₂^? ion which is the actual reactive species in aqueous cuprous chloride solutions containing hydrochloric acid. The reaction rate constants were calculated and correlated as a function of temperature.     

Absorption of oxygen by 2-ethylhexaldehyde

The kinetics of absorption of oxygen by 2-ethylhexaldehyde dissolved in 2-ethylhexanoic acid at concentrations up to 1.38 × 10^?3 mole/cm³ (20 wt.-%), in the presence of manganese acetate, was studied in a stirred cell and in bubble and packed bubble columns. Diffusion of oxygen was found to play a major role. The reaction was first order in oxygen and second order with respect to the aldehyde, and the overall third-order rate constant was found to be 2.98 × 10⁷ cm⁶ mole^?2 sec^?1 at 30°. The effect of cobaltous acetate on the specific rate of absorption of oxygen was also studied and manganese acetate was found to be the better catalyst.     

Absorption of oxygen by n-butyraldehyde

The kinetics of absorption of oxygen by n-butyraldehyde dissolved in n-butyric acid, in the range of concentrations up to 3·1 × 10^?3 gmole/cm³ (25 wt.-%), in the presence of manganese acetate, was studied in stirred cells and a bubble column. It was found that diffusion of oxygen is important. The reaction was found to be first-order in oxygen and second-order with respect to the aldehyde. The overall third-order reaction rate constant was found to be about 4 × 10⁶ (cm³/gmole)² sec^?1 at 20°. The effect of the catalysts, cobaltous acetate and (cobaltous + 4 cupric) acetates, on the specific rates of absorption of oxygen was also studied. Manganese acetate was found to be the best catalyst.     

Absorption of 2-butene and 2-methyl-2-butene in aqueous solutions of sulphuric acid

The kinetics of absorption of 2-butene in aqueous solutions of sulphuric acid was studied in a stirred cell in the range of acid concentration from 70·2 per cent w/w (11·5 g mole/l.) to 80·2 per cent w/w (14·56 g mole/l.). The absorption was found to conform to fast pseudo-first order mechanism. The pseudo-first order reaction rate constant at 28°C was found to vary from about 500 to 3·8 × 10⁶ sec^?1 over the above concentration range.The absorption of 2-methyl-2-butene (isoamylene) in aqueous solutions of sulphuric acid was also found to conform to fast psuedo-first order mechanism, in the range of acid concentration from 61·5 per cent w/w (9·395 g mole/l.) to 75 per cent w/w (12·845 g mole/l.). The pseudo-first order reaction rate constant at 30°C was found to vary from about 4·2 × 10⁵ to 2·2 × 10⁸ sec^?1 over the above concentration range.     

Alkaline hydrolysis of alkylated acidic groups on carbon black

Potentiometric pH-stat titration was performed on alkylated carbon black dispersed in aqueous solution at pH 9.0, 10.0 and 11.0 and alkaline hydrolysis rate constant of the alkylated functional groups on the carbon black was obtained therefrom. Carbon black treated with C₁-C₈n-alcohols in vapor or liquid phase was used in this experiment. Hydrolysis proceeded more rapidly for carbon black treated with lower alcohols. For each alkylated carbon black, the hydrolysis rate constant decreased with time and, after the hydrolysis rate diminished, a hydrolysis resistant fraction of alkylated groups remained. For example, the hydrolysis rate constants at 25°C were 24.33, 17.50 and 4.501 · mol^?1 · sec^?1 at 15 min and 6.00, 6.00 and 3.671 · mol^?1 · sec^?1 at 45 min after the start of hydrolysis at pH 9.0 for carbon black treated with C₂, C₃ and C₄ alcohols respectively.     

Absorption of phosphine in aqueous solutions of sodium hypochlorite and sulphuric acid

The kinetics of absorption of phosphine in aqueous solutions of sodium hypochlorite and sulphuric acid was studied in a stirred cell and a stirred contactor. The reaction of phosphine with aqueous solutions of sodium hypochlorite was found to first order with respect to phosphine and hypochlorite. The effect of pH on the second order rate constant was also investigated. The value of the second order rate constant was found to vary from 230 to 77,000 1./g mole sec at 28°C in the pH range of 12.95-9.40.The reaction of phosphene with aqueous solutions of sulphuric acid, in the range of concentrations of 80 to 92% by weight, was also found to be first order with respect to phosphine. The value of the pseudo first order rate constant was found to be in the range of 3 × 10⁶?4 × 10' sec_?1 at 28°C. Copper sulphate was found to be an effective catalyst in sulphuric acid solutions.     

Simultaneous absorption and reaction of two gases in a liquid/formation of ethyl chloride from ethylene and hydrogen chloride

The simultaneous absorption of ethylene and hydrogen chloride with chemical reaction in a medium of nitrobenzene containing dissolved catalyst (aluminium chloride) was studied. The experimental results indicated that the absorption occurs in the kinetic regime. The reaction was found to be first-order with respect to the reactants (ethylene and hydrogen chloride) as well as the catalyst. The rate constants calculated were 1·16×10⁵, 2·80×10⁵, 6·11×10⁵ and 1·44×10⁶ [cm³/g mole]²/sec at 30, 40, 50 and 60°C respectively and the activation energy 16600 cal/g mole.     

Fast Consecutive Intramolecular Processes Involving Protein and Fe(III) in Ferri-Cytochrome-c in Aqueous Solution

The reaction of H atoms (produced by nanosecond pulse radiolysis) with ferri-cytochrome-c in aqueous solution results in the second order formation of an absorption spectrum due to the addition of H atoms to the enzyme protein. This spectrum is not specific to the iron moiety. The rate constant of the addition is 1×10¹⁰M^?1 sec^?1. This is followed by two first order intramolecular processes with specific rates of ～ 1×10⁵ sec^?1 and ～ 2×10⁴ sec^?1. In these processes, specific spectra related to the α and β bands of ferro-cytochrome-c appear. The results are interpreted to show reduction equivalent transfer through the protein to the iron moiety.     

Thermal degradation of poly(vinyl chloride) in alkyl maleates

The thermal degradation of poly(vinyl chloride) has been investigated in diethyl, dibutyl and dioctyl maleate under nitrogen from 160°C to 210°C. The rate of dehydrochlorination was highest in dibutyl maleate and lowest in dioctyl maleate. The apparent activation energy calculated from the average value of the rate constant at each temperature for diethyl, dibutyl and dioctyl maleate was found to be 83.6 kJ mole^?1, 112.7 kJ mole^?1, and 150.5 kJ mole^?1, respectively. The rates of dehydrochlorination and the activation energy observed in alkyl maleates are higher than those observed in ethyl benzoate. In the visible range spectra the absorption at higher wavelengths is considerably reduced in alkyl maleates.     

The Free-Radical Cleavage of the Disulfide Bond (Studied by Pulse Radiolysis)

Reaction of H atoms with glutathione leads rapidly to H + RSSR → RS · + RSH. The first observed product is RS, the spectrum of which is obtained. The spectrum of the RS?SR radical was obtained by direct attack of e^?_aq on glutathione. The rate constants of these processes were also measured. k_e?aq + RSSR = (2.7 ± 0.3) × 10⁹ M^?1 sec^?1 k_{H + RSSR} = (1.0 ± 0.2) × 10¹⁰ M^?1 sec^?1 When the OD of RS?SR is plotted vs pH a titration curve is obtained. This is due to the protonation of RS?SR with a rate constant of 2.6 × 10¹⁰ M^?1 sec^?1 which is probably followed by a cleavage to RS and RSH. In both cases the RSSHR radical cannot be detected. The spectrum attributed to the RSSHR radical is more likely to be that of RS.     

Ionic mechanisms in pulse irradiated poly(vinyl chloride) system containing stabilizing additives

The pulse radiolysis studies of poly(vinyl chloride), PVC, film containing stabilizers i.e., Tinuvin P, Irgastab PVC 11, and Irganox 1076 have been carried out with the main aim of investigating ionic reactions in these systems. The evidences are presented concerning the formation of ionic transients in model solvents i.e. 2‐propanol and sec‐butyl chloride as well as in PVC film. In PVC‐stabilizer system under consideration the additives can contribute to the positive charge transfer processes whereas Tinuvin P, in addition may scavenge effectively electrons (the rate constant for e^?_solv scavenging in 2‐propanol equals 5.9 × 10⁹ mol^?1 dm³ s^?1) influencing the negative charge scavenging by PVC matrix itself and the HCl formation during the radiolysis of PVC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

The Reduction of Ferricytochrome c Studied by Pulse Radiolysis

The formation of ferrocytochrome c upon pulse radiolysis of aqueous solutions of ferricytochrome c has been studied by following spectral shifts at 550 nm and 700 nm. The reaction between ferricytochrome c and hydrated electrons was studied by following the decay of hydrated electrons as well as the ferrocytochrome c formation. The two processes proceed with the same rate which indicate diffusion-controlled processes with a second order rate constant of 1.1 × 10¹¹ M^?1 sec^?1. The reaction between ferricytochrome c and H atoms was studied in a system containing H atoms only and found to be a second order reaction with a rate constant of 1.5 × 10¹⁰ M^?1 sec^?1. The formation of ferrocytochrome c by reaction between ferricytochrome c and OH radicals proceed by a first step with a second order rate constant of 1.4 × 10¹⁰ M^?1 sec^?1 during which OH radicals react with the protein part of ferricytochrome c forming an organic radical. Some of these radicals then undergo intramolecular reduction with a rate constant of 3.1 × 10³ sec^?1.     

Effects of oxygen supply condition and specific biofilm interfacial area on phenol removal rate in a three‐phase fluidized bed bioreactor

The effects of oxygen supply conditions and specific biofilm interfacial area on the phenol removal rate in a three‐phase fluidized bed bioreactor were evaluated. The experimental data were well‐explained by the semi‐theoretical equation based on the assumption that the reaction rate follows first‐order reaction kinetics with respect to oxygen and zero‐order one with respect to phenol. Two cases, biological reaction as rate‐controlling step and oxygen absorption as rate‐controlling step, were both explicable by this semi‐theoretical equation. The maximum volumetric phenol removal rate was 27.4 kg·m^?3·d^?1.     

Kinetics of polyurethane formation between glycidyl azide polymer and a triisocyanate

Kinetics of the polyurethane formation between glycidyl azide polymer (GAP) and a polyisocyanate, Desmodur N‐100, were studied in the bulk state by using quantitative FTIR spectroscopy. The reaction was followed by monitoring the change in intensity of the absorption band at 2270 cm^?1 for NCO stretching in the IR spectrum, and was shown to obey second‐order kinetics up to 50% conversion. The activation parameters were obtained from the evaluation of kinetic data at different temperatures in the range of 50–80°C. The enthalpy and entropy of activation were found to be ΔH^? = 44.1 ± 0.5 kJ · mol^?1 and ΔS^? = ?196 ± 2 J · mol^?1l · K^?1, respectively. Dibutyltin dilaurate (DBTDL) was used as the curing catalyst. The kinetic study of the polyurethane formation between GAP and Desmodur N‐100 showed that the reaction is enormously speeded up in the presence of the catalyst, and the reaction obeys second‐order kinetics, provided that the catalyst concentration is kept constant. An investigation on the rate of the catalysed reaction depending on the catalyst concentration provided the order of the reaction, with respect to the DBTDL catalyst concentration, and the rate constant for the catalytic pathway of the reaction. The rate constant for the catalytic pathway was established to be 4.37 at 60°C, while the uncatalyzed reaction has a rate constant of 3.88 × 10^?6 L · mol^?1 · s^?1 at the same temperature. A rate enhancement factor of 23 was achieved by using 50 ppm catalyst. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 918–923, 2001     

The Kinetics of Complexed and Free Ho2 Radical in the Reaction of Ce+4 and H2O2

The intermediates formed in the reaction of Ce⁺⁴ with H₂O₂ in 0.5 M perchloric acid were studied, spectrophotometrically and through the quenching method, using a stopped-flow system. The spectrum in the UV range and the kinetics of the generated radicals and their dependence on Ce⁺³ concentration were investigated. On adding Ce⁺³ to the mixture, a change in the spectrum as well as in the recombination rate constant was observed. This behaviour was attributed to the formation of a complex between the cerous ion and the HO₂ radical. The values of the recombination rate constant of the complexed radical is 4.0 ± 0.4·10⁶ F^?1 sec^?1 while that of the free HO₂ radical is 0.9 ± 0.1·10⁶ F^?1 sec^?1. The stabilization constant of the complex was found to be 60 ± 18 F^?1.     

Anionic polymerization of styrene in triglyme-benzene mixtures

Living anionic polymerization of styrene was kinetically investigated in triglyme-benzene mixtures. At low concentrations of triglyme the overall propagation rate constant, k_p, was much larger than at the same concentration of monoglyme (DME) in DME-benzene mixtures. The Szwarc-Schulz plot did not have negative slopes for lithium and sodium salts at triglyme contents of 5～20vol%, and no contribution of free anions to the propagation was observed for the sodium salt. The sodium ion pair was more highly reactive than the lithium ion pair; thus at 25°C, the ion pair rate constant, k′_p, for the lithium salt was 43, 102, 135 and 165 M^?1sec^?1 at triglyme concentrations of 5, 10, 15, and 20%, respectively, while that for the sodium salt was 410, 920, and 1460 M^?1sec^?1 in 5, 10, and 15% triglyme, respectively. The dissociation constant, K, for the lithium salt was 2·4×10^?11, 1·9×10^?10 and 1·3×10^?9 M in 10, 15, and 20% triglyme, respectively and the free ion rate constant, k″_p, was 2～2·5×10⁴ M^?1sec^?1 for the lithium salt.     

Sulphoxidation of methyl radicals

The reaction of sulphur dioxide-oxygen mixtures with methyl radicals, generated by the photolysis of azomethane at Λ 3400 Å, has been studied in the temperature range 50–150° in an attempt to evaluate some of the basic reactions involved in the sulphoxidation of free radicals and hydrocarbons. Addition of sulphur dioxide to a mixture of methyl radicals and oxygen leads, unexpectedly, to an initially increased consumption of oxygen. A rate constant has been determined for the reaction: a value of 1·7 × 10¹⁶ mole^?2 cm⁶ sec^?1 being obtained. Using this value, the rate constant for the reaction: has been estimated to be ～ 7·8 × 10⁷ mole^?1 cm³ sec^?1. Comparison of the reactions of acetyl and methylsulphonyl radicals with oxygen and with radicals in dicates that in both cases acetyl radicals are much more reactive by ～ 10³ times.     

Mixed metal vinyl stabilizer synergism—reactions with model compounds

An allylic model compound for degrading PVC, cinnamyl chloride, was found to react with metal carboxylates in n-butyl acetate at 50°C with rates first order in each component. The corresponding metal chlorides and a mixture of rearranged and unrearranged allyl esters were isolated. With cadmium carboxylates, the rate constant is of the order of 300 × 10^?5 sec^?1; with barium carboxylates, two orders of magnitude slower. In the presence of excess barium carboxylate, the rate of reaction is first order in cadmium and independent of barium concentration; the product is, however, barium chloride. Under such conditions, only unrearranged allyl ester is recovered. These observations are interpreted in terms of a rapid step leading to formation of a carboxylate-bridged barium/cadmium intermediate. It is proposed that such intermediates displace chloride from allylic carbon by a concerted mechanism, generating chloride-bridged reaction products that collapse exclusively to barium chloride.     

Studies on the thermal stability of poly/vinyl chloride/ and vinyl chloride - carbon monoxide copolymers

Thermal stability of vinyl chloride/carbon monoxide copolymers synthetized in the presence of different proportions of carbon monoxide was studied in nitrogen, oxygen or air stream at 180°C. Dehydrochlorination rate increases proportionally to the incorporated carbonyl content. Effect of air and oxygen on acceleration of the decomposition is higher for PVC samples of regular structure than for the vinyl chloride/carbon monoxide copolymers. In the infra-red spectra recorded after the thermal oxidative decomposition, a broad absorption band appears between 1600 and 1800 cm^?1. Two peaks show the most emphasized increase: one at 1720 to 1730 cm^?1 assigned to the carbonyl group and another at about 1770 cm^?1 of unidentified origin. Additional oxidation products from the polyene yield a “shoulder” in the spectrum between 1600 and 1690 cm^?1.     

Kinetics of absorption of chlorine in acetic acid in the presence of homogeneous catalysts

The physical solubility of chlorine in acetic acid is sufficiently large (=1.00 mol dm^?3 at 333 K) to enable the kinetics of reaction between chlorine and acetic acid to be determined in the homogeneous phase. The product of reaction, monochloroacetic acid, is industrially important. The solubility of chlorine in acetic acid and monochloroacetic acid was determined. The homogeneous reaction kinetics between chlorine and acetic acid were studied using acetyl chloride and ferric chloride as catalysts. The heterogeneous kinetics of absorption of chlorine in acetic acid in the presence of ferric chloride as soluble catalyst was studied in a 10 cm agitated glass reactor. The reaction between dissolved chlorine and acetic acid was found to be very slow. In the agitated reactor the diffusion effects were completely eliminated and the reaction followed homogeneous kinetics. It was first order both with respect to chlorine as well as acetic acid. The values of second order rate constant were 2.9 × 10^?5 and 13.7 × 10^?5 dm³ mol^?1 s^?1 at 333 and 353 K, respectively.