The thermal unimolecular decomposition rate constants of ethoxy radicals

1999 ◽  
Vol 1 (12) ◽  
pp. 2935-2944 ◽  
Author(s):  
oise Caralp ◽  
Pascal Devolder ◽  
Christa Fittschen ◽  
Nathalie Gomez ◽  
Horst Hippler ◽  
...  
Keyword(s):  
Decomposition Rate ◽  
Rate Constants ◽  
Unimolecular Decomposition

Kinetics and mechanism of the oxidation of oxalate ion by tris(acetylacetonato)-manganese(III) and its hydrolytic derivatives in aqueous perchlorate media

1993 ◽  
Vol 71 (12) ◽  
pp. 2155-2159 ◽  
Author(s):  
Subrata Mukhopadhyay ◽  
Swapan Chaudhuri ◽  
Rina Das ◽  
Rupendranath Banerjee
Keyword(s):  
Free Radicals ◽  
Rate Constant ◽  
Decomposition Rate ◽  
Rate Constants ◽  
Kinetics And Mechanism ◽  
Unimolecular Decomposition ◽  
Decomposition Rate Constant ◽  
Mixed Complexes ◽  
Ph Range ◽  
Oxalate Ion

In the pH range 6.6–8.6, [MnL2(H2O)2]+ and [MnL2(H2O)(OH)] (HL = acetylacetone) oxidize oxalate ion (ox2−) to CO2 through the inner-sphere intermediates [MnL2(ox)]− and [MnL2(OH)(ox′)]2−, where ox′ is a half-bonded (unidentate) oxalate ion. Their rate constants of decomposition are 1.0 × 10−4 s−1 and 11.2 × 10−2 M−1 s−1 at 30 °C and at I = 1.0 M (NaClO4). Decomposition of these mixed complexes produces free radicals, presumably CO2−, which is further oxidized to CO2 by another Mn(III) in a fast step. At pH 4.2, [Mn(ox)3]3− is produced quantitatively when [ox]0 ≥ 0.12 M, which has been characterized spectrally, and its unimolecular decomposition rate constant k (= 2.7 × 10−4s−1 at 30 °C and I = 1.0 M) compares well with that reported earlier (2.44 × 10−4 s−1 at 25 °C and I = 1.0 M).

Decomposition of stumps 10 years after partial and complete harvesting in a southern boreal forest in Finland

2008 ◽  
Vol 38 (9) ◽  
pp. 2414-2421 ◽  
Author(s):  
Ekaterina Shorohova ◽  
Ekaterina Kapitsa ◽  
Ilkka Vanha-Majamaa
Keyword(s):  
Decomposition Rate ◽  
Rate Constants ◽  
Meta Analysis ◽  
Exponential Model ◽  
Published Data ◽  
Birch Bark ◽  
Spruce Bark ◽  
Betula Pubescens Ehrh ◽  
Opposite Tendency

We studied the decomposition of cut stumps of Norway spruce ( Picea abies (L.) Karst.), Scots pine ( Pinus sylvestris L.), and birches ( Betula pubescens Ehrh. and Betula pendula Roth.) 10 years after clear felling, low level retention felling, gap felling, and selection felling. Bulk density of wood, mass per surface area of bark, and mass of wood and bark for entire stumps were estimated. Using a single exponential model, annual decomposition rate constants (k) were calculated as 0.071, 0.052, and 0.041 ·year–1 for birch, spruce, and pine, respectively. The k values for wood decreased in the same order. For bark, the order was different: spruce bark decomposed slower than pine bark. Fragmentation accelerated mass loss. Pine and birch bark decomposed faster than pine and birch wood, whereas spruce showed the opposite tendency. The wood density and bark mass did not depend on retention levels. Diameter of stumps did not explain variation in decomposition either. The high importance of stumps for biodiversity, carbon, and nutrient cycling requires refinements to decomposition rate constants. Thus, further research based on new empirical data and meta-analysis of published data is needed to reveal factors influencing the decomposition process in situ.

Decomposition rate constants of Picea abies logs in southeastern Norway

1999 ◽  
Vol 29 (3) ◽  
pp. 372-381 ◽  
Author(s):  
Erik Næsset
Keyword(s):  
Picea Abies ◽  
Rate Constant ◽  
Cross Sections ◽  
Decomposition Rate ◽  
Rate Constants ◽  
Initial Density ◽  
Decomposition Rate Constant ◽  
Negative Exponential Function ◽  
Standing Trees ◽  
Negative Exponential

Decomposition rate constants were estimated from 384 cross sections of Norway spruce (Picea abies (L.) Karst.) logs with base diameter >7.0 cm collected in open areas at five different study sites in southeastern Norway. Fresh wood core samples were taken from 95 standing trees adjacent to the logs to estimate the initial density of these cross sections. Based on this chronosequence, a simple negative exponential function of time showed an average decomposition rate constant for all cross sections of 0.033 per year. Cross-section diameter, ground contact, soil moisture, and aspect were all found to have significant impacts on the decomposition rate constant. For different combinations of these characteristics the decomposition rate constant ranged from a minimum of 0.0165 per year to a maximum of 0.0488 per year.

Anharmonic effect of the decomposition reaction of the CF3CCl2O radical

2012 ◽  
Vol 90 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Qian Li ◽  
Wenwen Xia ◽  
Li Yao ◽  
Ying Shao
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Decomposition Reaction ◽  
Unimolecular Decomposition ◽  
Anharmonic Effect ◽  
Canonical Systems ◽  
Bond Scission

The rate constant of the unimolecular decomposition reaction of the CF3CCl2O radical was calculated by using the method proposed by Yao and Lin (YL method). Two important channels of decomposition occurring via C–C and C–Cl bond scission were investigated. The results show that C–Cl bond scission is the dominant channel during the decomposition of the CF3CCl2O radical. Especially, the reasonable anharmonic effect on the decomposition reaction was investigated. The results show that the harmonic rate constants are higher than those of the anharmonic case in both microcanonical and canonical systems. The anharmonic effect is more evident with increasing energy.

The Decomposition of Sodium Nitrite Solutions in Aqueous Sulphuric and Perchloric Acids

1963 ◽  
Vol 16 (6) ◽  
pp. 927 ◽  
Author(s):  
NS Bayliss ◽  
DW Watts
Keyword(s):  
Aqueous Solutions ◽  
Acid Composition ◽  
Sodium Nitrite ◽  
Decomposition Rate ◽  
Rate Constants ◽  
First Order ◽  
Order Dependence ◽  
Gaseous Products ◽  
Kinetics Of

The kinetics of the decomposition of aqueous solutions of sulphuric and perchloric acids containing sodium nitrite have been investigated at a number of temperatures. The technique involved flushing the decomposing solutions with dry nitrogen to remove the gaseous products. A first-order dependence of decomposition rate on "analytical nitrite" was found, the rate constants being dependent on the solvent acid composition.

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