Influence of Reaction Parameters on the First Principles Reaction Rate Modeling of a Platinum and Vanadium Catalyzed Nitro Reduction

2013 ◽  
Vol 17 (10) ◽  
pp. 1277-1286 ◽  
Author(s):  
Brian R. Crump ◽  
Charles Goss ◽  
Tom Lovelace ◽  
Rick Lewis ◽  
John Peterson
Keyword(s):  
First Principles ◽  
Reaction Rate ◽  
Reaction Parameters ◽  
Nitro Reduction

The kinetics of proton and deuteron transfer from 4-nitrophenylnitromethane and l-(4-nitrophenyl)-l-nitroethane to 2,7-dimethoxy-l,8-bis(dimethylamino)naphthalene in acetonitrile solvent

1981 ◽  
Vol 59 (21) ◽  
pp. 3034-3038 ◽  
Author(s):  
Kenneth T. Leffek ◽  
Przemyslaw Pruszynski
Keyword(s):  
Isotope Effect ◽  
Reaction Rate ◽  
Significant Contribution ◽  
Reaction Parameters ◽  
Deuterium Isotope Effect ◽  
First Order ◽  
Enthalpy Of Activation ◽  
Deuteron Transfer ◽  
Slow Dissociation ◽  
Kinetics Of

4-Nitrophenylnitromethane reacts with 2,7-dimethoxy-1,8-bis(dimethylamino)naphthalene in acetonitrile in a bimolecular proton transfer, which shows a primary deuterium isotope effect, kH/kD = 12.2 at 25 °C. The large isotope effect on the enthalpy of activation, (ΔHD≠ – ΔHH≠) = 4.6 ± 0.3 kcal mol−1 is consistent with a significant contribution of proton tunnelling to the reaction rate of the protium substrate.The analogous reaction of 1-(4-nitrophenyl)-1-nitroethane with the same base in acetonitrile gives contrasting kinetics and reaction parameters. The reaction is first order, showing no dependence on base concentration. While the isotope effect kH/kD = 9.3 at 25 °C, the enthalpy of activation difference (ΔHD≠ – ΔHH≠) is only 0.5 ± 0.1 kcal mol−1. It is concluded that the 1-(4-nitrophenyl)-1-nitroethane undergoes a slow dissociation, with a very small dissociation constant, followed by a fast association with the base to yield the carbanion ion-pair.

Decomposition of meta- and para-phenylphenol during ozonation process

2013 ◽  
Vol 67 (9) ◽  
Author(s):  
Magdalena Olak-Kucharczyk ◽  
Jacek Miller ◽  
Stanisław Ledakowicz
Keyword(s):  
Decay Rate ◽  
Rate Constants ◽  
Reaction Rate ◽  
Homogeneous System ◽  
Liquid System ◽  
Second Order ◽  
Direct Reaction ◽  
Reaction Parameters ◽  
Reaction Rate Constants ◽  
Ozonation Process

AbstractThe decomposition of meta-phenylphenol (m-PP) and para-phenylphenol (p-PP) in a heterogeneous gas-liquid system using ozone was investigated. The influence of different reaction parameters such as ozone and PP isomers concentration as well as pH and temperature of the reaction mixture on the PP decay rate was determined. The second-order rate constants for the direct reaction of molecular ozone, determined in a homogeneous system, were (5.85 ± 0.35) × 102 M−1 s−1 and (8.90 ± 0.33) × 102 M−1 s−1 for m-PP and p-PP, respectively. The rate constants for the reaction of m-PP and p-PP with ozone increased with increasing pH. The reaction rate constants with ozone were found to be (1.75 ± 0.02) × 109 M−1 s−1 and (1.86 ± 0.02) × 109 M−1 s−1 for m-PP and p-PP anions, respectively.

Predicting Diffusion Coefficients from First Principles via Eyring’s Reaction Rate Theory

2009 ◽  
Vol 294 ◽  
pp. 1-13 ◽  
Author(s):  
Manjeera Mantina ◽  
Long Qing Chen ◽  
Zi Kui Liu
Keyword(s):  
First Principles ◽  
Diffusion Coefficients ◽  
Reaction Rate ◽  
Harmonic Approximation ◽  
Impurity Diffusion ◽  
Rate Theory ◽  
Simplified Approach ◽  
Self Diffusion ◽  
Reaction Rate Theory ◽  
Jump Frequencies

A simplified approach to predicting diffusion coefficients directly from first-principles is proposed. In this approach, the atomic jump frequencies are calculated through the Eyring’s reaction rate theory while the temperature dependence of diffusion coefficients are accounted using phonon theory within the quasi-harmonic approximation. The procedure can be applied to both self-diffusion and impurity diffusion coefficients and different crystal systems. Applications to self-diffusion coefficients in fcc Cu, bcc Mo, hcp Mg and impurity diffusion coefficients of Li in fcc Al, W in bcc Mo and Cd in hcp Mg show agreement with experimental measurements.

scholarly journals Optimization of Three-Step Method For Biodiesel Production From Waste Cook Oil

2014 ◽  
Vol 27 (2) ◽  
pp. 6-10
Author(s):  
Kaniz Ferdous ◽  
M Rakib Uddin ◽  
M Rahim Uddin ◽  
Maksudur R Khan ◽  
MA Islam
Keyword(s):  
Fatty Acid ◽  
Silica Gel ◽  
Pour Point ◽  
Reaction Rate ◽  
Chemical Engineering ◽  
Biodiesel Production ◽  
Esterification Reaction ◽  
Reaction Parameters ◽  
Step Method ◽  
Standard Methods

In this paper, production of biodiesel from Waste Cook Oil (WCO) by three-step method and optimization of the process were studied. The properties of raw oil were measured by standard methods. The raw oil containing 1.9 wt% Free Fatty Acid (FFA) and viscosity was 54.53 mm2/s. Biodiesel was prepared from WCO by three-step method. In the three-step method, the first step was saponification of the oil followed by acidification to produce FFA and finally esterification of FFA to produce biodiesel. The reaction parameters in saponification, acidification and esterification reaction were optimized. Silica gel was used during esterification reaction to adsorb water produced in the reaction and silica gel to FFA ratio was 1.5:10 wt/wt. Hence the reaction rate was increased and finally the FFA was reduced to 0.98 wt%. A factorial design was studied for esterification reaction to obtain the higher yield of biodiesel. Finally various properties of biodiesel such as FFA, viscosity, specific gravity, cetane index, pour point, flash point etc. were measured and compared with biodiesel and petro-diesel standard. DOI: http://dx.doi.org/10.3329/jce.v27i2.17775 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 2, December 2012: 6-10

scholarly journals Catalytic Oxidation of CO on a Curved Pt(111) Surface: Simultaneous Ignition at All Facets Through a Transient CO-O Complex

2020 ◽  
Author(s):  
Fernando Garcia-Martinez ◽  
Carlos Garc´ıa-Fern´andez ◽  
Juan Pablo Simonovi ◽  
Adrian Hunt ◽  
Andrew Walter ◽  
...  
Keyword(s):  
First Principles ◽  
Oxidation Reaction ◽  
Chemical Species ◽  
Oxidation Of Co ◽  
Reaction Parameters ◽  
Systematic Analysis ◽  
Catalytic Activation ◽  
Co Oxidation Reaction ◽  
Catalytic Oxidation Of Co ◽  
Co Concentration

We combine PLIF and NAP-XPS to investigate the CO oxidation reaction at vicinal Pt(111) surfaces in the millibar regime, using a curved sample. We find that the catalytic activation of Pt occurs in all vicinal planes simultaneously,<br>irrespectively of the reaction parameters. The systematic analysis of chemical species across the entire curved surface provides the clues for this surprising behavior. As the surface CO concentration decreases when approaching ignition, minor amounts of oxygen build up at both steps and (111) terraces. First-principles theory indicates that the latter is forming a CO-Pt-O complex that binds CO molecules to terraces strongly, leveling its adsorption energy to that of low-coordinated steps, and explaining why CO abruptly desorbs at the same temperature along the di erent crystal facets that make up the curved Pt surface.

First-principles computation of electron transfer and reaction rate at a perovskite cathode for hydrogen production

2017 ◽  
Vol 19 (12) ◽  
pp. 8300-8306
Author(s):  
C. T. Liu ◽  
J. F. Chu ◽  
C. K. Lin ◽  
C. W. Hong
Keyword(s):  
Electron Transfer ◽  
Hydrogen Production ◽  
First Principles ◽  
Reaction Rate ◽  
Photoelectrochemical Cell

Electron transfer and its reaction rate at the perovskite cathode of a photoelectrochemical cell for hydrogen production.

scholarly journals The kinetics and mechanism of the ligand substitution reaction of aquapentacyanoruthenate(II) with d-penicillamine in aqueous medium

2020 ◽  
pp. 174751982096101
Author(s):  
Rupal Yadav ◽  
Radhey Mohan Naik
Keyword(s):  
Aqueous Medium ◽  
Reaction Rate ◽  
Electronic Effect ◽  
Ligand Substitution ◽  
Order Conditions ◽  
Reaction Parameters ◽  
First Order ◽  
Coloured Complex ◽  
Kinetics Of ◽  
Ligand Substitution Reaction

The kinetics of the formation of the light orange–coloured complex [Ru(CN)5D-PA]3− are studied spectrophotometrically through substitution of a coordinated H2O molecule in aquapentacyanoruthenate(II) [Ru(CN)5OH2]3− by interaction with D-penicillamine [D-PA] in aqueous medium at 490 nm (λmax of [Ru(CN)5D-PA]3−). The reaction is monitored under pseudo-first-order conditions, taking [D-PA] in excess over [Ru(CN)5OH23−]. The effects of various reaction parameters on the rate of the reaction are investigated. Experimental observations reveal that the variation in [D-PA] obeyed the first-order rate law while it is found to be invariant with [Ru(CN)5OH23−] in the whole experimental range. With ionic strength variation, as the reaction advances a decrease in the reaction rate is noticed. The product stoichiometry is assigned as 1:1. The ease of substitution at an H2O molecule in [Ru(CN)5OH23−] is considered on the basis of the electronic effect generated through interactions of the M–OH2 bond. A provisional mechanism based on the calculated results is proposed based on the slowest step of the reaction.

Modelling complete methane oxidation over palladium oxide in a porous catalyst using first-principles surface kinetics

2018 ◽  
Vol 8 (2) ◽  
pp. 508-520 ◽  
Author(s):  
Carl-Robert Florén ◽  
Maxime Van den Bossche ◽  
Derek Creaser ◽  
Henrik Grönbeck ◽  
Per-Anders Carlsson ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
First Principles ◽  
Total Pressure ◽  
Reaction Rate ◽  
Palladium Oxide ◽  
Surface Kinetics ◽  
Porous Catalyst

Modeled turnover frequencies for varying temperature and total pressure combined with reaction rate controlling regions.

Improved uniformity of densification of ceramic composites through control of the initial preform porosity distribution

1990 ◽  
Vol 5 (7) ◽  
pp. 1544-1548 ◽  
Author(s):  
Stanley Middleman ◽  
Brian Heble ◽  
Herman C.T. Cheng
Keyword(s):  
Chemical Vapor Deposition ◽  
Simulation Model ◽  
Vapor Deposition ◽  
First Principles ◽  
Reaction Rate ◽  
Chemical Vapor ◽  
Ceramic Composites ◽  
Simulation Tool ◽  
Densification Process ◽  
Porosity Distribution

Densification arising from chemical vapor deposition within a porous preform is modeled as a problem in diffusion and reaction. The effect of reaction rate on the nonuniformity of the final densified composite is explored. The possibility of achieving uniform densification by starting with an initially nonuniform porosity distribution is demonstrated with a simulation model. This model permits one to design a densification process from first principles using a simulation tool that yields results on a timescale far less than that of the processing laboratory.

scholarly journals Studies concerning the anion exchange resins catalyzed esterification of epichlorohydrin with organic acids

2009 ◽  
Vol 15 (3) ◽  
pp. 169-174
Author(s):  
Ioan Muresan ◽  
Teodor Malutan
Keyword(s):  
Organic Acids ◽  
Anion Exchange ◽  
Polymer Matrix ◽  
Reaction Rate ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Reaction Parameters ◽  
Strong Base ◽  
Anion Exchange Resins ◽  
Exchange Resins

The paper studies the esterification of carboxylic acids with epichlorohydrin over two macroporous strong base anion exchange resins with different polymer matrix. For both resins, the influence of reaction parameters (temperature, catalyst loading, molar ratio) on the reaction rate and the yields of the two isomeric esters were investigated.

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