Computer investigations on the mechanism of the influence of quencher concentration on the rate of simple bimolecular reaction

2006 ◽  
Vol 125 (17) ◽  
pp. 174501 ◽  
Author(s):  
Marek Litniewski
Keyword(s):  
Bimolecular Reaction ◽  
Quencher Concentration

Simple Modification Measurement of Photodegradability of Polymers by using Photo-induced Chemiluminescence Technique

2013 ◽  
Vol 10 (2) ◽  
pp. 51
Author(s):  
Siti Farhana Zakaria ◽  
Keith R Millington
Keyword(s):  
Free Radicals ◽  
Organic Materials ◽  
Oxidative Degradation ◽  
Working Life ◽  
Bimolecular Reaction ◽  
Synthetic Polymers ◽  
Accelerated Weathering ◽  
Simple Modification ◽  
Uv Absorbers ◽  
Irradiation Period

Polymers and organic materials that are exposed to sunlight undergo photooxidation, which leads to deterioration of their physical properties. To allow adequate performance under outdoor conditions, synthetic polymers require additives such as antioxidants and UV absorbers. A major problem with optimising polymer formulations to maximise their working life span is that accelerated weathering tests are empirical. The conditions differ significantly from real weathering situations, and samples require lengthy irradiation period. Degradation may not be apparent in the early stages of exposure, although this is when products such as hydroperoxides are formed which later cause acceleration of oxidation. A simple way of quantifying the number of free radicals presents in organic materials following exposure to light or heat is by measuring chemiluminescence (CL) emission. Most polymers emit CL when they undergo oxidative degradation, and it originates from the bimolecular reaction of macroperoxy radicals which creates an excited carbonyl.

EFFECTS OF COMPLEXING ON THE HOMOGENEOUS REDUCTION OF MERCURIC SALTS IN AQUEOUS SOLUTION BY MOLECULAR HYDROGEN

1956 ◽  
Vol 34 (10) ◽  
pp. 1372-1381 ◽  
Author(s):  
G. J. Korinek ◽  
J. Halpern
Keyword(s):  
Aqueous Solution ◽  
Molecular Hydrogen ◽  
Hydrogen Molecule ◽  
Bimolecular Reaction ◽  
Mercury Atom ◽  
Complexing Agents ◽  
Mercuric Ion ◽  
Rate Determining Step ◽  
Homogeneous Reduction

The effects of various complexing agents on the homogeneous reduction of mercuric salts by molecular hydrogen in aqueous solution were determined. In all cases the kinetics suggest that the rate-determining step is a bimolecular reaction between a mercuric ion or complex and a hydrogen molecule, probably leading to the formation of an intermediate mercury atom. The reactivity of various mercuric complexes was found to decrease in the following order: HgSO4 > Hg++ > HgAc2, HgPr2 > HgCl2 > HgBr2 > Hg(EDA)2++. Addition of anions such as OH−, CO3=, Ac−, Pr−, and Cl−, in excess of the amounts required to form stable mercuric complexes, was found to increase the rate. An interpretation of these effects is given.

scholarly journals Secondary organic material formed by methylglyoxal in aqueous aerosol mimics

2010 ◽  
Vol 10 (3) ◽  
pp. 997-1016 ◽  
Author(s):  
N. Sareen ◽  
A. N. Schwier ◽  
E. L. Shapiro ◽  
D. Mitroo ◽  
V. F. McNeill
Keyword(s):  
Organic Material ◽  
Aldol Condensation ◽  
Bimolecular Reaction ◽  
Ionization Mass ◽  
Aerosol Formation ◽  
Hydronium Ion ◽  
Rate Limiting Step ◽  
Tropospheric Aerosol ◽  
Heterogeneous Processes ◽  
Rate Limiting

Abstract. We show that methylglyoxal forms light-absorbing secondary organic material in aqueous ammonium sulfate and ammonium nitrate solutions mimicking tropospheric aerosol particles. The kinetics were characterized using UV-Vis spectrophotometry. The results suggest that the bimolecular reaction of methylglyoxal with an ammonium or hydronium ion is the rate-limiting step for the formation of light-absorbing species, with kNH4+II=5×10−6 M−1 min−1 and kH3O+II≤10−3 M−1 min−1. Evidence of aldol condensation products and oligomeric species up to 759 amu was found using chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol-CIMS). Tentative identifications of carbon-nitrogen species and a sulfur-containing compound were also made using Aerosol-CIMS. Aqueous solutions of methylglyoxal, with and without inorganic salts, exhibit significant surface tension depression. These observations add to the growing body of evidence that dicarbonyl compounds may form secondary organic material in the aerosol aqueous phase, and that secondary organic aerosol formation via heterogeneous processes may affect seed aerosol properties.

scholarly journals Theoretical study on the thermal dissociation of FOX-7 promoted by NO2

2021 ◽  
Author(s):  
Shuhui Yin ◽  
Qiong Zhu ◽  
Jianyong Liu ◽  
Panwang Zhou
Keyword(s):  
Reaction Mechanism ◽  
Hot Spots ◽  
Quantum Chemical ◽  
High Performance ◽  
Catalytic Effect ◽  
Theoretical Study ◽  
Energetic Material ◽  
Thermal Dissociation ◽  
Bimolecular Reaction ◽  
Low Sensitivity

1,1-diamino-2,2-dinitroethene (FOX-7) is a novel energetic material with high performance and low sensitivity. In order to deeply understand the reaction mechanism in the initiation “hot spots” of FOX-7 and reveal the growth mechanism of these initiation “hot spots” in the explosion process, the detailed mechanisms of bimolecular reaction of NO2 and FOX-7, as well as the subsequent reactions have been investigated by the quantum chemical calculations. The mechanism of NO2 and FOX-7 bimolecular reaction and the catalytic effect of NO2 were revealed by three key dissociation paths. It is demonstrated that the NO2 molecule plays an important role in promoting the decomposition of the FOX-7 molecule, and the main exothermic pathways were the reactions between oxidizing intermediates (NO, NO2), and reducing intermediates (CO, NH3).

RADIATION CHEMISTRY OF CYCLOHEXANE: III. EFFECT OF BENZENE AND IODINE ON THE ISOTOPIC COMPOSITION OF RADIOLYTIC HYDROGEN FROM C6D12–C6H12 MIXTURES

1961 ◽  
Vol 39 (11) ◽  
pp. 2163-2170 ◽  
Author(s):  
P. J. Dyne ◽  
W. M. Jenkinson
Keyword(s):  
Isotopic Composition ◽  
Radiation Chemistry ◽  
Bimolecular Reaction ◽  
Specific Yield ◽  
Unimolecular Decomposition ◽  
Common Precursor

The isotopic composition of hydrogen evolved in the radiolysis of C6D12–C6H12 mixtures has been measured in the presence of various amounts of benzene and iodine. The yield of the unimolecular decomposition and the specific yield of the bimolecular reaction are reduced in approximately the same proportion as the yield of total hydrogen. It is concluded that (i) iodine and benzene interact to a comparable extent with both unimolecular and bimolecular decomposition modes, (ii) it is probable that neither of these additives act by scavenging, and (iii) it is probable that they act by quenching a common precursor of the two decomposition modes.

Exact Dynamics in a Model of the Bimolecular Reaction A+B→ 0

1992 ◽  
Vol 290 ◽  
Author(s):  
Eric Clément ◽  
Patrick Leroux-Hugon ◽  
Leonard M. Sander
Keyword(s):  
Exact Solution ◽  
Steady State ◽  
Initial Conditions ◽  
Finite Size ◽  
Bimolecular Reaction ◽  
Reaction Model

AbstractWe have previously given an exact solution [1] for the steady state of a model of the bimolecular reaction model A+B→ 0 due to Fichthorn et al. [2]. The dimensionality of the substrate plays a central role, and below d=2 segregation on macroscopic scales becomes important: above d=2 saturation sets in for finite size systems. Here we extend our treatment to give an exact account of the dynamics and show how various initial conditions develop into the segregated and saturated regimes. In certain conditions we find logarithmic relaxation which is related to the dimensionality.

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