Decomposition kinetics using

The decomposition kinetics of an organic peroxide, as judged by 10-h HLT, largely determines the suitabiUty of a particular peroxide initiator in an end use appHcation (22). Other important factors ate melting point, solubiUty, cost, safety, efficiency, necessity for refrigerated storage and shipment, compatibihty with production systems, effects on the finished product, and potential for activation. 

Some of the complications associated with the use of AIBN may be avoided by use of alternative azo-initiators. Azobisfmelhyl isobutyrale) (AIBMe) has a decomposition rate only slightly less than AIBN and has been promoted for use in laboratory studies of polymerization85 because the kinetics and mechanism of its decomposition kinetics are not complicated by ketenimine formation. 

Mass loss determinations refer to the total change resulting from reactant decomposition and usually include contributions from a mixture of product compounds, some of which would normally be condensed under conditions used for accumulatory pressure measurements. Such information concerned with the overall process is, however, often usefully supplemented by evolved gas analyses (EGA) using appropriate analytical methods. Sestak [130] has made a detailed investigation of the effects of size and shape of reactant container on decomposition kinetics and has recommended that the sample be spread as a thin layer on the surfaces of a multiple plate holder. The catalytic activity of platinum as a reactant support may modify [131] the apparent kinetic behaviour. 

The chemical properties of oxide surfaces have been studied by several methods, including oxygen exchange. This method has been used to investigate the mechanisms of heterogeneous reactions for which oxides are active catalysts [36]. The dimerization step does not necessarily precede desorption and Malinin and Tolmachev [634], in one of the few reviews of decomposition kinetics of solid metal oxides, use this criterion to distinguish two alternative reaction mechanisms, examples being... 

The decomposition kinetics of the N-Br-amino acids was studied spectro-photometrically by following the fall in absorbance at the wavelength of the absorbance maximum of the N-bromoamino acid, in a Milton Roy Spectronic 3000 Array or a Beckman DU65 single-beam spectrophotometer, both equipped with a cell carrier thermostated to within 0.1 °C by water flow. Kinetic experiments were initiated using a hand-driven HI-TECH SFA-12 Rapid Kinetics Accessory with a 1.00 cm flow cell. 

Di-f-butyl peroxide is a commonly used free-radical initiator that decomposes according to first-order kinetics. Use the following data to estimate AVact for the decomposition in toluene at 120°C ... 

Initial activity is important to ensure fast unloading and loading cycles. The second requirement for repeated use of alanate batteries is long-term stability. Whereas titanium colloids show superior performance in terms of decomposition kinetics, titanium nitride-based materials are superior in long-term stability. The latter can be seen comparing both catalytic materials in several runs (Fig. 19.8). 

In dynamic systems we may have the situation where a series of runs have been conducted and we wish to estimate the parameters using all the data simultaneously. For example in a study of isothermal decomposition kinetics, measurements are often taken over time for each run which is carried out at a fixed temperature. 

Isoperibolic instruments have been developed to estimate enthalpies of reaction and to obtain kinetic data for decomposition by using an isothermal, scanning, or quasi-adiabatic mode with compensation for thermal inertia of the sample vessel. The principles of these measuring techniques are discussed in other sections. 

Estimating the isothermal lifetime of pharmaceutical coatings using thermogravimetric decomposition kinetics... 

In this study, the degradability of phenol in aqueous solutions was investigated with using ozone. Additionally, decomposition kinetic of phenol in the presence of ozone was calculated using maximum rate constants, from graphics of concentration versus time. 

It is somewhat confusing that the term critical diameter is also used by those interested in the potential of an energetic material to undergo thermal runaway. Because, by definition, the energetic material releases heat when it decomposes, it has the potential to increase its local environmental temperature. Depending on the decomposition kinetics of the material, at some critical dimension the charge can self-heat to catastrophic reaction. This can be referred to in terms of the critical diameter or, more often, in terms of the initial environmental temperature that allows this scenario, the critical temperature . 

The decomposition kinetics were also calculated by Usmanov and Magarra 287) using a dimensionless molecular transfer equation. Perchloryl fluoride can be heated almost to the softening point of glass without explosion 92). 

McHale et al, Determination of the Decomposition Kinetics of Hydrazine Using a Single-Pulse Shock Tube , Ibid, 341-51 28) A.I. 

Bell and Caldin [9] and Caldin and Peacock [10] investigated the decomposition kinetics of nitramine under the influence of alkali in various solvents. Dimethylaniline was used as a base. According to Bell [11] the decomposition of nitramine proceeds through the formation of the aci-form ... 

Recall the simple relationship derived by Jellinek and Srinivasai shown in Eq. (9). F l is dependent on decomposition kinetics and should not vary with small changes in dopant concentration. Using Eqs. (2) and (9) and setting dUda. equal to zero and solving for ttmax yields a ax I/ > which is consistent with empirical observations. 

Peracetic acid decomposition kinetics in the presence of cobalt or copper acetates were studied in the same apparatus used for the manganese-catalyzed reaction. However, in these studies it was used as a batch reaction system. The reactor was charged with peracetic acid (ca. 0.5M in acetic acid) and allowed to reach the desired temperature. At this time the catalyst (in acetic acid) was added. Samples were withdrawn and quenched with potassium iodide at measured time intervals. 

The decomposition kinetics is an important characteristic of polymeric azo compounds for their subsequent use as initiators of a radical polymerization and the synthesis of block copolymers. 

The carboxylation of ethylenediamine (229) is first order in protonated (229) and the rate constant was an order of magnitude lower than that for (229) under identical conditions.204 The effects of solvents on the decomposition kinetics of some diacyl peroxidases (230) was assessed using time-resolved FTIR spectroscopy at <3 kbar and <155 °C.205... 

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