Kinetics of thermophilic, anaerobic oxidation of straight and branched chain butyrate and valerate

2003 ◽  
Vol 84 (2) ◽  
pp. 195-204 ◽  
Author(s):  
D. J. Batstone ◽  
P. F. Pind ◽  
I. Angelidaki
Keyword(s):  
Anaerobic Oxidation ◽  
Branched Chain ◽  
Kinetics Of

A study of sensitized explosions - X. The kinetics of decomposition of chloropicrin and of the hydrogen-oxygen and hydrogen-chlorine reactions sensitized by chloropicrin

1950 ◽  
Vol 204 (1076) ◽  
pp. 34-50 ◽  
Keyword(s):  
Kinetic Scheme ◽  
Straight Chain ◽  
Chlorine Atoms ◽  
Kinetics Of Decomposition ◽  
Direct Explanation ◽  
Satisfactory Account ◽  
Different Temperatures ◽  
Viii And Ix ◽  
Branched Chain ◽  
Kinetics Of

A kinetic scheme is suggested for the decomposition of chloropicrin which is shown to be in agreement with the results of the work of Smith & Steacie (1938 a, b ), and which provides an explanation of the sensitizing action of chloropicrin on the hydrogen-oxygen and hydrogen-chlorine reactions described in parts VIII and IX (Ashmore & Norrish 1950 a, b ): CCl 3 NO 2 → Cl + ... k 1 CCl 3 NO 2 → COCl 2 + NOCl... k 2 Cl + NOCl → Cl 2 + NO... k 3 Cl + CCl 3 NO 2 → remove Cl... k 4 Estimates of the relative concentrations of chlorine atoms at various stages of the decomposition at different temperatures are made. The concentration of chlorine atoms passes through a maximum, and at temperatures above 340°C this maximum is probably reached within 1 msec. It occurs earlier, and is greater in magnitude, the higher the chloropicrin pressure at a given temperature or the higher the temperature for a given concentration of chloropicrin. These variations are shown to provide a direct explanation of the results for the range 340 to 400°C described in part IX, and to enable the results of part VIII to be explained by a modification of the scheme proposed by Dainton & Norrish (1941) for the nitrosyl chloride-hydrogen-oxygen reaction. This modification consists of an allowance for the variation in the initial number of chain-centres arriving in the reaction vessel, the variation being due to changes in the precise location within the entry tube of the maximum concentration of the chlorine atoms which initiate the chains. Kinetic schemes are suggested for the hydrogen-chlorine-chloropicrin reaction in the temperature region 100 to 200°C. A straight chain scheme, with chains initiated from reaction k 1 , is combined with a thermal condition for ignition to give a satisfactory account of the variation of the ignition limits with concentration of chloropicrin, with proportion of reactants, and with temperature, and also to account for the course of the slow reaction below the ignition limit. A branched chain mechanism is also discussed and is shown to account for the results only if the branching reaction is of the form H+Cl 2 +CCl 3 NO 2 →HCl+Cl+Cl+NO+COCl 2 . The experimental results do not allow a decision to be made between these possible schemes.

scholarly journals Induction of the branched-chain 2-oxo acid dehydrogenase complex in 3T3-L1 adipocytes during differentiation

1983 ◽  
Vol 214 (1) ◽  
pp. 177-181 ◽  
Author(s):  
D T Chuang ◽  
C W C Hu ◽  
M S Patel
Keyword(s):  
Pyruvate Dehydrogenase ◽  
Specific Activity ◽  
Pyruvate Dehydrogenase Complex ◽  
Common Mechanism ◽  
Acid Dehydrogenase ◽  
Oxoglutarate Dehydrogenase ◽  
Branched Chain ◽  
Kinetics Of ◽  
Acid Dehydrogenase Complex ◽  
Dehydrogenase Complex

The activities of 2-oxo acid dehydrogenase complexes were measured during hormone-mediated differentiation of 3T3-L1 preadipocytes into adipocytes. Specific activity of leucine-activated branched-chain 2-oxo acid dehydrogenase complex increased approx. 10-fold in 3T3-L1 adipocytes compared with 3T3-L1 preadipocytes. In contrast, specific activity of the 2-oxoglutarate dehydrogenase complex increased by only 3-fold in 3T3-L1 adipocytes. The three catalytic component enzymes of the branched-chain 2-oxo acid dehydrogenase complex and the pyruvate dehydrogenase complex showed concomitant increases in their specific activities. A close similarity in kinetics of induction of the branched-chain 2-oxo acid dehydrogenase complex and the pyruvate dehydrogenase complex in 3T3-L1 adipocytes suggests that a common mechanism may be involved in hormone-dependent increases in the activities of the catalytic components of these two complexes in 3T3-L1 adipocytes during differentiation.

The thermal oxidation of methylene chloride

1959 ◽  
Vol 250 (1261) ◽  
pp. 197-211 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Chain Length ◽  
Methylene Chloride ◽  
Decomposition Reaction ◽  
Average Chain Length ◽  
Static System ◽  
Chain Process ◽  
Branched Chain ◽  
Considerable Detail ◽  
Kinetics Of

A study of the kinetics of the slow oxidation of methylene chloride has been made using a static system and the results of this are compared with those of flow-system experiments in which the composition of the reacting system was determined in considerable detail by gaschromatographic analysis. The reaction shows all the symptoms of a degenerately branched chain process and is similar to the corresponding thermal decomposition reaction in many respects. Several of the chlorinated hydrocarbon minor products are identical with those found in the thermal decomposition and this, together with kinetic evidence, suggests that the primary chain is the same in both reactions, oxygen intervening only in the conversion of the intermediate, dichlorethylene, to the end products HCl and carbon monoxide, and in the branching step, through which it modifies the overall rate. As in the thermal decomposition several of the organic minor products are susceptible to attack by chlorine atoms participating in the main chain and this prevents an accurate evaluation of the chain length by measurement of the rate of formation of termination products. The average chain length, however, appears to be of the order of ten. Methylene chloride + oxygen mixtures show a single explosion limit above about 600° C, which obeys the Semenov equation log 10 p = A / T + B , A being a constant for the system and B depending on the geometry of the vessel.

Kinetics of Anaerobic Treatment

1991 ◽  
Vol 24 (8) ◽  
pp. 35-59 ◽  
Author(s):  
S. G. Pavlostathis ◽  
E. Giraldo-Gomez
Keyword(s):  
Fatty Acids ◽  
Mass Transfer ◽  
Anaerobic Treatment ◽  
Specific Substrate ◽  
Anaerobic Oxidation ◽  
Monod Kinetics ◽  
Decay Rate Constant ◽  
Kinetic Coefficients ◽  
Kinetics Of ◽  
Chain Fatty Acids

A review of the kinetics of anaerobic treatment and the reported values of such kinetic parameters as the maximum specific substrate utilization rate (k), the half-saturation constant (Ks), the microbial growth yield (Y), and the microorganism decay rate constant (b) are presented. The available kinetic information is presented for each subprocess: (a) hydrolysis of complex, paniculate organic materials; (b) fermentation of amino acids and sugars; (c) anaerobic oxidation of long-chain fatty acids and alcohols; (d) anaerobic oxidation of intermediary products (such as short-chain fatty acids); (e) homoacetogenesis; and (f) methanogenesis. The intrinsic rates of each step as well as mass transfer limitations and their effect on the intrinsic kinetics are discussed and areas requiring further research are also identified. Substantial variation exists in the reported values of the kinetic coefficients. This variation is due in part to the variability in mode of operation, environmental and operational conditions in the various studies as well as to the lack of a widely accepted standard procedure for measuring and expressing the biokinetic coefficients. The hydrolysis step is usually assumed to follow first-order kinetics. Whenever the kinetics of the hydrolysis step were studied, they were generally found to be the limiting-step in the overall conversion of complex substrates to methane. With the exception of the hydrolysis step, all other subprocesses of anaerobic treatment have been successfully modeled by following Monod kinetics. The Contois and Chen & Hashimoto model has also been used quite extensively to account for the effect of influent substrate concentration on effluent quality. Based on a brief overview of the observed phenomena related to the kinetics of mass transfer in methanogenesis, it is concluded that with but few exceptions, the evidence for the significance of mass transfer effects in the different reactor configurations is circumstantial and, in some cases, contradictory. Our understanding of the kinetics of paniculate substrate removal in biofilms is still incomplete for engineering applications, and more research is necessary.

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