Arrhenius constants

The fact that hot spots are required for explosive initiation can be seen by calculating for the bulk temperature, say 350 K, and the anticipated hot-spot temperature, say 700 K. We take typical values of Arrhenius constants for secondary explosives QjCp 2500 K, //c = 25,(X)0 K, and V = 10 s V Hence... 

A simple power law rate expression (usually first order) will be sufficient if Arrhenius constants can be fitted. 

The hydrolytic depolymerisation of PETP in stirred potassium hydroxide solution was investigated. It was found that the depolymerisation reaction rate in a KOH solution was much more rapid than that in a neutral water solution. The correlation between the yield of product and the conversion of PETP showed that the main alkaline hydrolysis of PETP linkages was through a mechanism of chain-end scission. The result of kinetic analysis showed that the reaction rate was first order with respect to the concentration of KOH and to the concentration of PETP solids, respectively. This indicated that the ester linkages in PETP were hydrolysed sequentially. The activation energy for the depolymerisation of solid PETP in a KOH solution was 69 kJ/mol and the Arrhenius constant was 419 L/min/sq cm. 21 refs. 

Arrhenius constant Specific heat Energy of activation Flow rate... 

The term A in Equation (2.6) is a constant known as the Arrhenius constant and E is the energy of activation derived from collision theory (Atkins, 1978). The enthalpy of activation can be calculated from transition state theory (Jencks, 1969) as... 

Conversion data are obtained in a CSTR at several residence times and two temperatures. Verify that the reaction is second order and find the Arrhenius constants, f = C/C0... 

The reaction, CO + Cl2 = > C0CI2, in the presence of activated carbon catalyst was studied at several temperatures with the results shown Potter Baron, CEP 47, 473, 1951). The controlling mechanism is believed to be reaction between adsorbed CO and Cl2, but the amount of adsorbed CO is relatively small. Find the Arrhenius constants of all the terms. 

AROMATIC AMINO ACID-GLYOXYLATE AMINOTRANSFERASE Aromatic amino acid hydroxylases, PHENYLALANINE HYDROXYLASE TYROSINE HYDROXYLASE TRYPTOPHAN HYDROXYLASE ARRHENIUS CONSTANT... 

The BPO decomposes with a specific rate constant of about 10 /sec, an Arrhenius constant (A) of about 10 , and an activation energy of about 28 kcal/mol (about 115 kJ/mol). As noted earlier, not all radicals initiate new chains. Some terminate prior to initiation forming inactive products, mainly phenyl benzoate (Equation 6.5). Thus, as noted, an efficiency constant (/) is used that reflects the ratio of BPO that actually form chains. 

A = Arrhenius constant which depends upon the nature of gas. The equation can also be written as ... 

Concentration of A Arrhenius constants Arrhenius constant Constant in equation 5.82 Surface area per unit volume Parameter in equation 5.218 Cross-sectional area Concentration of B Stoichiometric constants Parameter in equation 5.218 Concentration of gas in liquid phase Saturation concentration of gas in liquid Concentration of G-mass Concentration of D-mass Dilution rate DamkOhler number Critical dilution rate for wash-out Effective diffusion coefficient Dilution rate for maximum biomass production Dilution rate for CSTF 1 Dilution rate for CSTF 2 Activation energy Enzyme concentration Concentration of active enzyme Active enzyme concentration at time t Initial active enzyme concentration Concentration of inactive enzyme Total enzyme concentration Concentration of enzyme-substrate complex with substance A... 

Figure 2.60 [38] presents the permeability of water vapor through several polymers as a function of temperature. It should be noted that permeability properties drastically change once the temperature exceeds the glass transition temperature. This is demonstrated in Table 2.16 [66], which presents Arrhenius constants for diffusion of selected polymers and CH3OH. 

A = Arrhenius constant e = base of natural logarithm Ea = activation energy R = universal gas constant T = temperature (K)... 

The terms C and b are constants, and a = EJ2.303R, where EA is the Arrhenius constant. All three terms can be found by graphical procedures.4... 

This expression for contains two unknown rate constants, k and ks. The Arrhenius coefficients for these rate constants were determined using the 140 °C conversion data from Figure 7.6. The parameters were estimated for both the case of chain transfer to monomer, and again for chain transfer to DH. Given that the two chain transfer models differ only in their predictions of Mw and that the fit was against conversion data, the optimum Arrhenius constants for both cases were the same ... 

Equation 11 is now used to estimate feed conversion, which in turn is introduced into Equation 10 to generate the desired rate constant data. Modeling of the rate constant data centers on developing suitable functional forms for its parameters (A and E), followed by their estimation. It turns out that, for practical purposes, a single E-value of 55,000 cal/ g-mol can be used for all naphthas (29). The Arrhenius constant requires further study. 

---