(CHP) is classified as a flammable hazard in NFPA 43B. Fires or explosions
induced by thermal hazards ascribed to the unstable hydroperoxyl or peroxyl
groups are often reported. This sequence studies is aimed at the decomposition
phenomena associated with the reactive and incompatible characteristics of
CHP mixed with alkaline solutions. Various alkalines were used for comparing
the relative impact of bases and effects on concentrations. Exothermic onset
temperatures and heats of decomposition of these incompatible mixtures were
performed by differential scanning calorimetry (DSC). Comparisons of exothermic
onset temperature, peak power, heat of decomposition, etc., were assessed
to verify the severity of incompatible hazards in these systems. When mixed
with a small amount of the hydroxides (in the production or storage of CHP),
CHP will be more labile or unstable because of lower exothermic temperature.
In addition, to elucidate the final products and propose mechanisms of the
reaction of CHP mixed with alkaline solution, the analytical results were
carried out by GC/MS and IR. The exhibited reactivity was complicated and
significantly affected by the alkaline solutions. The reaction schemes have
been proposed in this study. These results are especially important in process
safety design for producing CHP and its related compounds, such as phenol, α-cumyl
alcohol (CA), acetophenone (AP), and dicumyl peroxide (DCPO).
Authors:Z. Gontarz, R. Grzybowska, and R. Sabaliński
The observed relationships are presented of the solid phase reactivity of the following salts: NaMnO4, Na2MnO4, Na3MnO4, Na4MnO4, Na2MnO3, Na2Mn2O5, Na5MnO4, Na4Mn2O5, NaMnO2, Na4MnO3, Na2MnO2 and Na2Mn2O3.
This paper is a continuation of the paper “Examination of Micro Grid Operation in Island Condition, Focusing on Voltage Control” . It has presented the assessment of micro grids’ voltage and reactive power control. The increasing integration of intelligent energy distribution networks has to serve the interest of the consumers. Therefore, it is necessary to examine the quality of the electricity supply with regard to the voltage quality as well. How is it possible to ensure the regulation in those cases, e.g. in case of island operation? In the paper the model developed and used for simulating the micro grids are introduced and it is also shown how to apply them for island operation assessment. With the help of a model network the results of the simulations are presented and the conclusions are evaluated.
Authors:R. Lee, H. Hou, J. Tseng, M. Chang, and C. Shu
Organic peroxides are commonly employed as an initiator for polymerization, a source of free radicals, a hardener, and a linking
agent. Due to its relatively weak oxygen-oxygen bond, di-tert butyl peroxide (DTBP) has been categorized as flammable type or Class III by the National Fire Protection Association (NFPA).
The transport of dangerous goods (TDG) has published a warning against DTBP that it could potentially induce violent heat,
explosion, fire and self-ignition under certain circumstances.
DTBP has been recommended as an international standard sample for estimating the performance of several calorimeters, such
as glass tube tests, differential scanning calorimetry (DSC), and vent sizing package 2 (VSP2). In this study, we measured
the precise temperature changes and heat flow with the above-mentioned testing instruments. However, some runaway incidents
caused by DTBP have demonstrated the reaction temperature could be as low as ambient temperature. The reactivity and the hazardous
incompatibility with sulfuric acid (H2SO4) and hydrochloric acid (HCl) of DTBP have not been evident, and the runaway hazards involved in different processing conditions
were clarified in this study by implementing the two calorimeters. Acid-catalyzed characteristics and reaction hazards of
DTBP could be acquired, such as heat of decomposition (ΔHd) and exothermic onset temperature (T0).
Cobalt acetate reacts with aniline, 2-, 3- and 4-chloroanilinehydrobromides in the solid state to give the products CoBr2. 2 amine in which the acetate is replaced by bromide and the amine gets attached to the metal in a concerted step. The products have been identified by elemental, spectral and thermoanalytical methods. The kinetics of these reactions have been studied by the mass loss method. The values of energy of activation are 142.0, 41.0, 77.0 and 71.4 kJ mol−1. The greater reactivity of 2-chloro is due to ortho effect. An intermediate adduct (RNH3)2(Co(CH3COO)2Br2) has also been characterized.
Authors:B. Roduit, Ch. Borgeat, B. Berger, P. Folly, B. Alonso, and J. N. Aebischer
Summary An advanced study on the thermal behaviour of double base (boost and sustain propellant) rocket motor used in a ground to air missile has been carried out by differential scanning calorimetry (DSC). The presence of two propellants as well as the different experimental conditions (open vs. closed crucibles) influence the relative thermal stability of the energetic materials. Several methods have been presented for predictions of the reaction progress of exothermic reactions under adiabatic conditions. However, because decomposition reactions usually have a multi-step nature, the accurate determination of the kinetic characteristics strongly influences the ability to correctly describe the progress of the reaction. For self-heating reactions, incorrect kinetic description of the process is usually the main source of serious errors for the determination of the time to maximum rate under adiabatic conditions (TMRad). It is hazardous to develop safety predictive models that are based on simplified kinetics determined by thermoanalytical methods. Applications of finite element analysis (FEA) and accurate kinetic description allow determination of the effect of scale, geometry, heat transfer, thermal conductivity and ambient temperature on the heat accumulation conditions. Due to limited thermal conductivity, a progressive temperature increase in the sample can easily take place resulting in a thermal explosion. Use of both, kinetics and FEA , enables the determination of the reaction progress and temperature profiles in storage containers. The reaction progress and temperature can be determined quantitatively at every point in time and in space. This information is essential for the design of containers of self-reactive chemicals, cooling systems and the measures to be taken in the event of a cooling failure.
In order to reveal the reactivity of toluenethiols, the hydrogen isotope exchange reaction between one of three toluenethiols (o–,m–, andp–) and poly (vinyl alcohol) labeled with tritium was observed at 50 90°C. The reaction was analyzed with both the data obtained and theA
-McKay plot method, and the following has been quantitatively clarified: (1) the reactivity order of toluenethiols is (o–>(m–)>(p–); (2) the temperature dependences of the reactivity of toluenethiols are nearly equal; (3) the reactivity of benzenethiol is considerably decreased by the CH3 group bonded to the ortho position.
Authors:Ryan Robinson, Fabrice Patisson, and Bo Björkman
≤ 0.93 can possibly be attributed to a reaction mechanism where advancement of the reaction interface is related to the layered crystal structure of Ca(OH) 2 , i.e. if product nucleation occurs at the more-reactive edge surfaces of a plate-like crystal
The interaction between the halogen atom and the aromatic substrate, responsible for the deviation from the Reactivity-Selectivity Principle in homolytic aromatic halogenation in the high energy region (hot homolytic aromatic halogenation) is discussed.