Kinetics and mechanism of oxidation of amido black by sodium N-halo-p-toluenesulfonamides in acidic medium: Spectrophotometric approach

The kinetics of oxidative decolorization of amido black (AB, Naphthol blue black) by chloramine-T (CAT) and bromamine-T (BAT) in acidic medium has been investigated spectrophotometrically (λmax = 618 nm) at 298 K. Kinetic runs were performed under pseudo first-order conditions of [Oxidant]o >> [AB]o. Under identical experimental conditions, reactions with both the oxidants follow identical kinetics with a first-order dependence on each [Oxidant]o and [AB] and a fractional-order dependence on [HClO4]. Stoichiometry of the reaction was found to be 1:4 and the oxidation products were identified. The reaction was studied at different temperatures and various activation parameters have been computed. Effects of p-toluenesulfonamide, halide ions, ionic strength and dielectric constant of the medium have been investigated. Reaction mixture fails to induce polymerization of acrylonitrile. The rate of oxidation of AB is about three-fold faster with BAT as compared to CAT. This may be attributed to the difference in electrophilicity of Cl+ and Br+ ions and also the Vander Waals radii of chlorine and bromine. Plausible mechanism and related rate law have been deliberated for the observed kinetics

Structure of Verbs in Malto

Malto is a North Dravidian language spoken in Eastern India. It is an agglutinating language with SOV word order and suffixing morphology. The finite verb word in Malto maximally carries information about valence adjusting operations, tense-aspect-mood, negation and gender-number-person agreement with the subject. The non-finite verbs take suffixes marking adverbialisation, complementation, relativisation, participialisation and relative tense. Syntactically, there is only one finite verb in a sentence and all the other verbs preceding it are non-finite. This paper is a descriptive analysis of the structure of Malto verbs and an outcome of a language documentation project with the intention of describing the formal structure of the Suariya Pahariya variety of Malto. This work is a follow up on grammatical accounts on Malto by Doerse (1884), Das (1973) and Mahapatra (1979)

Selective Oxidation of Pregabalin Drug Molecule: Exploration of Scope, Reaction Mechanism and Kinetic Modeling

The kinetics and mechanism of (RuCl3 + OsO4) in combination and, RuCl3 and OsO4 alone catalyzed oxidation of pregabalin (PGB) drug with chloramine-T have been investigated at 313 K in aqueous alkaline medium. The kinetic characteristics were found to be varied for each catalyzed reactions. In all the three catalyzed reactions, the reaction rate shows a first-order dependence of rate on [CAT]0 and a negative-fractional-order on [NaOH]. The order of [PGB]0 is found to be unity incase of [OsO4], but it is fractional in both RuCl3 and [RuCl3 + OsO4] catalyzed reactions. The orders with respect to [RuCl3] and [OsO4] are less than one whereas it is unity in case of [RuCl3 + OsO4]. Activation parameters have been evaluated. 2-isobutylsuccinic acid was identified as the oxidation product of PGB. Under identical set of experimental conditions, the reaction rates revealed that all the three catalyzed reactions are about 25 to 71-fold faster than the uncatalyzed reactions. The catalytic efficiency of these catalysts follows the order (RuCl3 + OsO4) > OsO4 > RuCl3. The observed reactivity sequence may be attributed to the different d-electronic configuration of the catalysts. Most noteworthy is the significant catalytic activity of 71-fold in case of (RuCl3 + OsO4) catalyst. It justifies the synergistic effect of (RuCl3 + OsO4) catalyst on the oxidation of PGB drug. An isokinetic relationship is observed with ß = 366 K, indicating that enthalpy factors are controlling the rate. The reaction mechanisms put forward and rigorous kinetic models deduced, give the best fit to the experimental results for each catalyzed reactions

Kinetics of dopamine oxidation by sodium N-bromo-p-toluenesulphonamide in acid medium. A mechanistic approach

The oxidation kinetics of dopamine (DPM) by sodium N-bromo-p-toluenesulphonamide (bromamine-T or BAT) was investigated at 40°C in HClO4 medium. The rate is first order in BAT0, fractional order in DPM0 and inverse fractional in H+. Addition of reaction product, p-toluenesulphonamide, or halide ions and variation of ionic strength of the medium have no significant effect on the rate. The dielectric effect is positive. The solvent isotope effect has been studied in D2O medium. The reaction fails to induce the polymerisation of acrylonitrile. The Michaelis-Menten type of kinetics is observed. Activation parameters for the overall reaction and also for the rate-limiting step were computed. Dopa-o-quinone or 2-(3â²4â²-benzoquinone) ethylamine was identified as the oxidation product of DPM. A mechanism consistent with the observed kinetics is proposed and discussed

Mechanistic chemistry of oxidation of balsalazide with acidic chloramine-​T and bromamine-​T: A comparative spectrophotometric kinetic study

Balsalazide (BSZ) belongs to a class of non-​steroidal anti-​inflammatory drugs. Kinetics and mechanism of oxidn. of BSZ with sodium N-​halo-​p-​toluenesulfonamides viz., chloramine-​T (CAT) and bromamine-​T (BAT) in HClO4 medium have been spectrophotometrically investigated (λmax = 357 nm) at 303 K. Under comparable exptl. conditions, reactions with both the oxidants follow a first-​order dependence of rate on [BSZ] and fractional-​order dependence on each [oxidant] and [HClO4]​. Activation parameters and reaction consts. have been computed. 2-​hydroxy-​5-​nitrosobenzoic acid and 3-​(4-​nitroso-​benzoylamino)​propionic acid are identified as the oxidn. products of BSZ with both CAT and BAT. The rate of oxidn. of BSZ is about five-​fold faster with BAT than with CAT. Plausible mechanism and related rate law have been deduced for the obsd. kinetics

Conversion of imidazoles to imidazolones with chloramine-​B: kinetic and mechanistic study

Oxidative conversion of 1H-​imidazole (IzlH) and 2-​substituted imidazoles viz., 2-​ethyl-​1H-​imidazole (2-​EtIzlH)​, 2-​methyl-​1H-​imidazole (2-​MeIzlH)​, 1H-​imidazole-​2-​ester (2-​EsIzlH)​, and 1H-​imidazole-​2-​carbaldehyde (2-​CaIzlH) to the corresponding imidazolones with sodium N-​chlorobenzenesulfonamide or chloramine-​B (CAB) were established. This reaction was kinetically investigated at 303 K in HClO4 medium. Under comparable exptl. conditions, the oxidn. reactions followed identical kinetics for all the five imidazoles with a first-​order dependence of rate on [CAB]​o and fractional-​order dependence each on [imidazole]​o and [H+]​. Effects of added benzenesulfonamide, halide ions, NaClO4, and MeOH on the rate of reaction have been studied. Reaction products were identified and characterized by GC-​MS and NMR spectral anal. The rates are measured at different temps. and the composite activation parameters have been computed from the Arrhenius plots. Isokinetic temp. (β) was found to be 449 K which is higher than the exptl. temp. (303 K)​, indicating that the rate has been under enthalpy control. Relative reactivity of these imidazoles is in the order: 2-​EtIzlH > 2-​MeIzlH > IzlH > 2-​EsIzlH > 2-​CaIzlH. H2O+Cl have been postulated as the reactive oxidizing species. The reaction mechanism and the derived rate law are in good agreement with the obsd. exptl. results. Spectroscopic studies have been made for an intermediate complex formation between CAB and imidazole. Advantages of the present method include: mild reaction conditions, cost-​effectiveness, short reaction time, ease of isolation of products, and the use of eco-​friendly reagents. Hence, the methodol. developed could be adopted for the facile oxidative conversion of imidazoles to imidazolones and can be scaled up to industrial operation with suitable modification

Oxidation of tetracaine hydrochloride by chloramine-b in acid medium: Kinetic modeling

Tetracaine hydrochloride (TCH) is one of the potent local anaesthetics. A kinetic study of oxidation of tetracaine hydrochloride by sodium N-chlorobenzenesulfonamide (chloramine-B or CAB) has been carried in HClO 4 medium at 303 K. The rate shows first-order dependence on CAB o, shows fractional-order dependence on substrate o, and is self-governing on acid concentration. Decrease of dielectric constant of the medium, by adding methanol, increased the rate. Variation of ionic strength and addition of benzenesulfonamide or NaCl have no significant effect on the rate. The reaction was studied at different temperatures and the activation parameters have been evaluated. The stoichiometry of the reaction was found to be 1: 5 and the oxidation products were identified by spectral analysis. The conjugate free acid C6H5SO2NHCl of CAB is postulated as the reactive oxidizing species. The observed results have been explained by plausible mechanism and the related rate law has been deduced. © 2014 Jayachamarajapura Pranesh Shubha and Puttaswamy

N-oxidation of pyrazines by bromamine-B in perchloric acid medium: Kinetic and mechanistic approach

Kinetic investigations on the oxidation of pyrazine and four 2-substituted pyrazines viz., 2-methylpyrazine, 2-ethylpyrazine, 2-methoxypyrazine and 2-aminopyrazine by bromamine-B (BAB) to the respective N-oxides have been studied in HClO4 medium at 303 K. The reactions show identical kinetics being first-order each in BABo and pyrazineo, and a fractional-order dependence on H+. Effect of ionic strength of the medium and addition of benzenesulfonamide or halide ions showed no significant effect on the reaction rate. The dielectric effect is positive. The solvent isotope effect was studied using D2O. The reaction has been studied at different temperatures and activation parameters for the composite reaction have been evaluated from the Arrhenius plots. The reaction showed 1:1 stoichiometry and the oxidation products of pyrazines were characterized as their respective N-oxides. Under comparable experimental conditions, the oxidation rate of pyrazines increased in the order: 2-aminopyrazine > 2-methoxypyrazine > 2-ethylpyrazine > 2-methylpyrazine > pyrazine. The rates correlate with the Hammett � relationship and the reaction constant � was found to be -0.8, indicating that electron donating centres enhance the rate of reaction. An isokinetic temperature of β = 333 K, indicated that the reaction was enthalpy controlled. A mechanism consistent with the experimental results has been proposed in which the rate determining step is the formation of an intermediate complex between the substrate and the diprotonated species of the oxidant. The related rate law in consistent with observed results has been deduced

Evaluation of metals release from oil sands coke : an ecotoxicological assessment of risk and hazard to aquatic invertebrates

The oil sands operations in northeast Alberta, Canada, employ unconventional processes to produce synthetic crude oil (SCO). Because the extracted bitumen, ¡®the form of oil in oil sands¡¯, is highly viscous, it requires thermal upgrading to produce SCO. Coking technology is used to convert heavy bitumen fractions to lighter volatile fractions. During this process, an enormous volume of solid coke is produced and the metal impurities (e.g. Al, Fe, Mn, Ni, Ti and V) present in bitumen fractions end-up in the coke particles. As coke demands significant space for storage, oil sands companies are exploring options for placing coke into reclamation landscapes for long term storage and recovery. However, coke holds appreciable amounts of potentially leachable metals that may impede the performance of reclamation landscapes. Although two previous coke leaching studies had showed that coke released metals into water at concentrations exceeding the Canadian guidelines for the protection of aquatic life, the ecotoxicological hazard and risk of these metals were not well characterized. Therefore, the overall goal of this research was to characterize the fate and toxicity of metals associated with coke. In this research, the toxicity of coke leachates collected from oil sands field sites and those artificially generated in the laboratory were evaluated using a standard three-brood Ceriodaphnia dubia tests. Coke leachates (CLs) collected over a period of 20 months from two field lysimeters were found to be acutely toxic to C. dubia. Vanadium concentrations were significantly higher (p¡Ü0.05) than concentrations of all other metals in CLs from both lysimeters, and also in leachates from a laboratory batch renewal leaching study. Furthermore, toxic unit (TU) calculations suggested that Ni and V were likely the cause of CL toxicity, but this was not explicitly proven. Therefore, a chronic toxicity identification and evaluation (TIE) approach was adopted to identify and confirm the cause(s) of CL toxicity. Coke was subjected to a 15 day batch leaching process in the laboratory at pH 5.5 and 9.5 in order to characterize the effect of pH on metals release from coke, and to generate CLs for use in TIE tests. The 7-day LC50 estimates for C. dubia survival were 6.3% and 28.7% (v/v) for CLs generated at pH 5.5 and 9.5, respectively. The dissolved concentrations of Mn, Ni and Zn were high (p¡Ü0.05) in pH 5.5 CL, whereas Al, Mo and V were high (p¡Ü0.05) in pH 9.5 CL. Evidence gathered from a series of chronic TIE tests revealed that Ni and V were the cause of toxicity in pH 5.5 CL, whereas V was the primary cause of toxicity in pH 9.5 CL. Further, the influence of bicarbonate, chloride and sulfate ions on metals release, speciation and Ni and V toxicity was investigated. The type and amount of metals released from coke was significantly influenced by the ion type elevated in the leaching solution. Specifically, sulfate influenced mobilization of Ni, Fe, Mn and Zn from coke, whereas bicarbonate enhanced Al, Mo and V releases from coke. With respect to toxicity, increasing bicarbonate decreased the 7-day Ni2+ IC50 from 6.3 to 2.3 ¦Ìg Ni2+/L suggesting enhanced Ni toxicity at high pH or alkalinity. Conversely, sulfate showed a protective effect against V toxicity to C. dubia. The research presented in this thesis suggests that coke will not be inert when stored in reclamation landscapes and that metals, particularly Ni and V, could reach ecotoxicologically relevant levels in surface waters or substrate porewaters, under favourable leaching conditions. Operationally, efforts should focus on remediation and monitoring of metals released from coke, particularly Ni and V, in impacted wetlands, especially before discharging water into natural wetlands and/or local streams and rivers

Scale-Out Algorithm For Apache Storm In SaaS Environment

The main appeal of the Cloud is in its cost effective and flexible access to computing power. Apache Storm is a data processing framework used to process streaming data. In our work we explore the possibility of offering Apache Storm as a software service. Further, we take advantage of the cgroups feature in Storm to divide the computing power of worker machine into smaller units to be offered to users. We predict that the compute bounds placed on the cgroups could be used to approximate the state of the workflow. We discuss the limitations of the current schedulers in facilitating this type of approximation as the resources are distributed in arbitrary ways. We implement a new custom scheduler that allows the user with more explicit control over the way resources are distributed to components in the workflow. We further build a simple model to approximate the current state and also predict the future state of the workflow due to changes in resource allocation. We propose a scale-out algorithm to increase the throughput of the workflow. We use the predictive model to measure the effects of many candidate allocations before choosing it. Our approach analyzes the strengths and drawbacks of Stela algorithm and design a complementary algorithm. We show that the combined algorithm complement each others strengths and drawbacks and provides allocations to maximize throughput for much larger set of scenarios. We implement the algorithm as a stand alone scheduler and evaluate the strategy through physical simulation on the Apache Storm Cluster and on software simulations for a set of workflows. Adviser: Ying L