scholarly journals Catalytic Effect of Cetyltrimethylammonium Bromide on the Oxidation of Triethylene glycol by Chloramine-T in Acidic Medium

2008 ◽  
Vol 5 (4) ◽  
pp. 894-903 ◽  
Author(s):  
Vandana Sharma ◽  
K. V. Sharma ◽  
V. W. Bhagwat
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Reaction Rate ◽  
Catalytic Effect ◽  
Triethylene Glycol ◽  
Chloride Ion ◽  
Effect Of Temperature ◽  
Rate Determining Step ◽  
Excess Concentration ◽  
Chloramine T ◽  
Catalyzed Oxidation

The kinetics and mechanism of cetyltrimethylammonium bromide catalyzed oxidation of triethylene glycol [2,2'-ethylene diqxybis(ethanol)] by chloramine-T in acidic acid medium have been investigated. The reaction is first order dependence on chloramine-T and fractional order for triethylene glycol with excess concentration of other reactants. The catalytic effect due to cetyletrimethylammonium bromide has been studied. The small salt effect and increase in the reaction rate with increasing dielectric constant suggest the involvement of neutral molecule in the rate-determining step. The addition ofp-toluene sulfonamide retards the reaction rate. The effect of chloride ion on the reaction also studied. The effect of temperature on the reaction has been investigated in the temperature range 313-333K and thermodynamic parameters were calculated from the Arrhenious plot. A tentative mechanism consistent with the experimental results has been proposed.

scholarly journals Kinetics and mechanism of cetyltrimethylammonium bromide catalyzed oxidation of diethylene glycol by chloramine-T in acidic medium

2003 ◽  
Vol 68 (7) ◽  
pp. 535-542 ◽  
Author(s):  
V.W. Bhagwat ◽  
J. Tiwari ◽  
A. Choube ◽  
B. Pare
Keyword(s):  
Diethylene Glycol ◽  
Acidic Medium ◽  
Cetyltrimethylammonium Bromide ◽  
Reaction Rate ◽  
Chloride Ions ◽  
Kinetics And Mechanism ◽  
Product Analysis ◽  
Rate Determining Step ◽  
Chloramine T ◽  
Catalyzed Oxidation

The kinetics and mechanism of the C16TABcatalyzed oxidation of diethylene glycol (2,2?-oxydiethanol) by chloramine-T in acidic medium has been studied. The reaction has a first-order dependence on chloramine-T. With excess concentrations of other reactants, the reaction rate follows fractional order kinetics with respect to [diethylene glycol]. The micellar effect due to cetyltrimethylammonium bromide, a cationic surfactant, has been studied. The reaction is catalyzed by chloride ions as well. The small salt effect and increase in the reaction rate with increasing dielectric constant suggest the involvement of neutral molecules in the rate determining step. Addition of p-toluenesulfonamide retards the reaction rate. On the basis of product analysis, a pertinent mechanism is proposed.

scholarly journals Kinetics and Mechanistic Study of Cetyltrimethylammonium Bromide Catalyzed Oxidation of Tetraethylene Glycol byN-Chlorosaccharin in Acidic Medium

2008 ◽  
Vol 5 (3) ◽  
pp. 598-606
Author(s):  
Vandana Sharma ◽  
K. V. Sharma ◽  
V. W. Bhagwat
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Mechanistic Study ◽  
Tetraethylene Glycol ◽  
Aqueous Acetic Acid ◽  
Acetic Acid Medium ◽  
First Order ◽  
Dielectric Effect ◽  
Catalyzed Oxidation

The kinetics and mechanism of cetyltrimethylammonium bromide catalyzed oxidation of tetraethylene glycol [2,2'-(oxibis(ethylenoxy)diethanol)] byN-chlorosaccharin in aqueous acetic acid medium in presence of perchloric acid have been investigated at 323K. The reaction is first order dependence on Nchlorosaccharin. The reaction rate follows first order kinetics with respect to [tetraethylene glycol] with excess concentration of other reactants. The miceller effect due to cetyltrimethylammonium bromide, a cationic surfactant has been studied. The change in ionic strength shows negligible salt effect. The dielectric effect is found to be positive. Addition of one of the products (saccharin) retards the reaction rate. Activation parameters are calculated from the Arrhenious plot. A possible mechanism consistent with the experimental results has been proposed.

Kinetics of Photochemical Oxidation of Glucose by Chloramine-T in Acidic Medium: A Mechanistic Approach

2013 ◽  
Vol 816-817 ◽  
pp. 7-12
Author(s):  
Meena Wadhwani ◽  
Shubha Jain
Keyword(s):  
Acidic Medium ◽  
Reaction Rate ◽  
Accurate Method ◽  
Photochemical Oxidation ◽  
First Order ◽  
Mechanistic Approach ◽  
Excess Concentration ◽  
Chloramine T ◽  
Kinetics Of ◽  
Oxidation Of Glucose

A simple, convenient and accurate method for the kinetic study of photochemical oxidation of glucose by chloramine-T in acidic medium is described. The kinetic investigation shows the first order dependence of reaction rate on chloramine-T. With excess concentration of other reactants the reaction rate follows fractional order kinetics with respect to substrate. The reaction is catalyzed by H+ ions as well. A small salt effect and increase in reaction rate with increasing the intensity of light source is also observed. Addition of p-toluene sulphonamide retards the reaction rate. A suitable mechanism in agreement with observed kinetics has been proposed

HOMOGENEOUS CATALYSIS OF D2–H2O EXCHANGE BY RUTHENIUM (III) CHLORIDE: EVIDENCE FOR THE HETEROLYTIC SPLITTING OF HYDROGEN

1966 ◽  
Vol 44 (6) ◽  
pp. 671-675 ◽  
Author(s):  
Jack Halpern ◽  
Brian R. James
Keyword(s):  
Exchange Rate ◽  
Exchange Reaction ◽  
Homogeneous Catalysis ◽  
Isotopic Exchange ◽  
Chloride Ion ◽  
Product Distribution ◽  
Hydrogen Ion ◽  
Rate Determining Step ◽  
Exchange Product ◽  
Catalyzed Oxidation

The prediction, based on earlier studies of the ruthenium(III) chloride catalyzed oxidation of H2 by iron(III), that in the absence of iron(III) or other oxidants ruthenium(III) chloride should catalyze homogeneously the isotopic exchange between D2 and H2O has been confirmed. A kinetic study was made of this exchange reaction in which the dependence of the exchange rate and of the exchange product distribution (HD:H2 ratio) on the concentrations of ruthenium(III), hydrogen ion, and chloride ion were determined. The results, and in particular the observation that the HD:H2 ratio of the exchange product increases with the concentrations cf H+ and Cl−, support the view that the ruthenium (III)-catalyzed oxidation of D2 by iron(III) and the D2–H2O exchange reaction proceed through related mechanisms involving a common rate-determining step in which D2 is split heterolytically and a deuteridoruthenium(III) complex is formed.

Kinetics of carbon monoxide methanation on a Ni/SiO2 catalyst

1990 ◽  
Vol 55 (7) ◽  
pp. 1678-1685
Author(s):  
Vladimír Stuchlý ◽  
Karel Klusáček
Keyword(s):  
Carbon Monoxide ◽  
Reaction Rate ◽  
Catalyst Activity ◽  
Adsorbed Hydrogen ◽  
Reaction Products ◽  
Co Methanation ◽  
Molar Ratios ◽  
Rate Determining Step ◽  
Higher Temperature ◽  
Kinetics Of

Kinetics of CO methanation on a commercial Ni/SiO2 catalyst was evaluated at atmospheric pressure, between 528 and 550 K and for hydrogen to carbon monoxide molar ratios ranging from 3 : 1 to 200 : 1. The effect of reaction products on the reaction rate was also examined. Below 550 K, only methane was selectively formed. Above this temperature, the formation of carbon dioxide was also observed. The experimental data could be described by two modified Langmuir-Hinshelwood kinetic models, based on hydrogenation of surface CO by molecularly or by dissociatively adsorbed hydrogen in the rate-determining step. Water reversibly lowered catalyst activity and its effect was more pronounced at higher temperature.

The dehydrogenation of 1,4-dihydronaphthalene by tetrachloro-p-benzoquinone

1976 ◽  
Vol 54 (14) ◽  
pp. 2261-2265 ◽  
Author(s):  
Z. M. Hashish ◽  
I. M. Hoodless
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Reaction Rate ◽  
Second Order ◽  
Charge Transfer Complexes ◽  
Ion Transfer ◽  
Hydride Ion ◽  
Rate Determining Step ◽  
Hydride Ion Transfer

The dehydrogenation of 1,4-dihydronaphthalene by tetrachloro-p-benzoquinone in phenetole solution has been investigated. The present work does not fully confirm earlier studies which report that the reaction follows second-order kinetics and that the hydride ion transfer is rate determining. In the investigations described in this paper second-order kinetics are only observed in the later stages of the reaction and a 1:1 stoichiometry of the reactants in the process is not obtained. Substitution of tritium in the 1,4-positions of the hydrocarbon appears to not significantly affect the reaction rate. The present results indicate that charge-transfer complexes are formed in the reaction and it is suggested that electron transfer within these complexes could be the rate-determining step in the dehydrogenation.

scholarly journals Catalytic Influence of Water Vapor on Lean Blowoff and NOx Reduction for Pressurised Swirling Syngas Flames

2017 ◽  
Author(s):  
Daniel Pugh ◽  
Philip Bowen ◽  
Andrew Crayford ◽  
Richard Marsh ◽  
Jon Runyon ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Reaction Rate ◽  
Catalytic Effect ◽  
Laminar Flame ◽  
Nox Reduction ◽  
Flame Temperature ◽  
Stability Limit ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Water Loading

It has become increasingly cost-effective for the steel industry to invest in the capture of heavily carbonaceous BOF (Basic Oxygen Furnace) or converter gas, and use it to support the intensive energy demands of the integrated facility, or for surplus energy conversion in power plants. As industry strives for greater efficiency via ever more complex technologies, increased attention is being paid to investigate the complex behavior of by-product syngases. Recent studies have described and evidenced the enhancement of fundamental combustion parameters such as laminar flame speed due to the catalytic influence of H2O on heavily carbonaceous syngas mixtures. Direct formation of CO2 from CO is slow due to its high activation energy, and the presence of disassociated radical hydrogen facilitates chain branching species (such as OH), changing the dominant path for oxidation. The observed catalytic effect is non-monotonic, with the reduction in flame temperature eventually prevailing, and overall reaction rate quenched. The potential benefits of changes in water loading are explored in terms of delayed lean blowoff, and primary emission reduction in a premixed turbulent swirling flame, scaled for practical relevance at conditions of elevated temperature (423 K) and pressure (0.1–0.3 MPa). Chemical kinetic models are used initially to characterize the influence that H2O has on the burning characteristics of the fuel blend employed, modelling laminar flame speed and extinction strain rate across an experimental range with H2O vapor fraction increased to eventually diminish the catalytic effect. These modelled predictions are used as a foundation to investigate the experimental flame. OH* chemiluminescence and OH planar laser induced fluorescence (PLIF) are employed as optical diagnostic techniques to analyze changes in heat release structure resulting from the experimental variation in water loading. A comparison is made with a CH4/air flame and changes in lean blow off stability limits are quantified, measuring the incremental increase in air flow and again compared against chemical models. The compound benefit of CO and NOx reduction is quantified also, with production first decreasing due to the thermal effect of H2O addition from a reduction in flame temperature, coupled with the potential for further reduction from the change in lean stability limit. Power law correlations have been derived for change in pressure, and equivalent water loading. Hence, the catalytic effect of H2O on reaction pathways and reaction rate predicted and observed for laminar flames, are compared against the challenging environment of turbulent, swirl-stabilized flames at elevated temperature and pressure, characteristic of piratical systems.

scholarly journals Methyl Iodide Adsorption on Reduced Silver-Functionalized Silica Aerogel: How Temperature Impacts the Adsorption?

2021 ◽  
Author(s):  
Siqi Tang ◽  
Seungrag Choi ◽  
Lawrence Tavlarides
Keyword(s):  
Methyl Iodide ◽  
Photoelectron Spectroscopy ◽  
Silica Aerogel ◽  
Reaction Rate ◽  
Reaction Pathway ◽  
Effect Of Temperature ◽  
Functionalized Silica ◽  
Contributing Factors ◽  
X Ray ◽  
Temperature Impacts

To understand the effect of temperature to the adsorption, 104 ppbv and 1044 ppbv methyl iodide (CHI) adsorptions on reduced silver-functionalized silica aerogel (Ag-Aerogel) at 100, 150 and 200 ℃ were performed. In the experiments, a significantly high uptake rate (3 – 4 times higher than that at 100 and 150 ℃) was observed for the 104 ppbv adsorption at 200 ℃. To explain such behavior, a potential reaction pathway was proposed and multiple physical analyses including nitrogen titration, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were performed. Based on the results, the contributing factors appear to be the formation of different Ag-I components induced by temperature, higher silver site availability, decreasing diffusion limitation, and increasing reaction rate described by the Arrhenius relationship.

Osmium(VIII) Catalyzed Oxidation of Acetone and Ethylmethyl Ketone by Chloramine-T

1972 ◽  
Vol 27 (10) ◽  
pp. 1161-1163 ◽  
Author(s):  
S. P. Mushran ◽  
R. Sanehi ◽  
M. C. Agraval
Keyword(s):  
Acidic Medium ◽  
Present Note ◽  
Alkaline Media ◽  
Alkaline Solutions ◽  
Slow Step ◽  
First Order ◽  
Chloramine T ◽  
Kinetics Of ◽  
Catalyzed Oxidation ◽  
High Redox Potential

The Osmium (VIII) catalyzed oxidation of acetone and ethylmethyl ketone by chloramine-T, in highly alkaline solutions showed first order dependence to chloramine-T and osmium (VIII). The order of the reactions with respect to alkali and ketone were found to be fractional, being ~-0.82 and 0.3 respectively. No effects of ionic strength were evident. The mechanism has been proposed on the basis of the formation of a complex between N-chlorotoluene-p-sulfonamide and osmium (VIII) in the slow step, which in turn oxidizes the enol anion of the reducing substrate in the fast step.During the study of the mechanism of oxidations by chloramine-T, the kinetics of the oxidation of α-hydroxy acids 1 in presence of osmium (VIII) as catalyst, glycerol2 in neutral and alkaline media, p-cresol3 in an acidic medium, hexacyanoferrate (II)4 in a feebly acidic medium (pH 6-7) and aliphatic aldehydes 5 in alkaline media have been investigated.Despite the high redox potential6 of the chloramine-T/toluene sulfonamide system (1.138 V at pH 12), the oxidation of acetone does not take place in absence of catalyst and that of ethylmethyl ketone proceeds only in highly alkaline solutions7 (NaOH>0.01 M). In the present note the kinetics of the osmium (VIII) catalyzed oxidation of acetone and ethylmethyl ketone have been recorded.

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