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The potentially explosive reaction of hydrogen peroxide (H2O2) and copper chloride (CuCl2) was investigated. Pressure tests revealed that the reaction was strongly temperature - dependent and can easily undergo runaway reaction. Nevertheless, there was only a slight pressure increase at the low temperatures studied or when using low concentrations of CuCl2. Under the conditions generating the slight pressure increase, hypochlorite anions (ClO−) are generated and the acidity increases. As the reaction reaches completion, ClO− disappears, and the acidity decreases. Interestingly, the addition of phosphate buffer to maintain the weakly acid conditions led to a runaway reaction, and the use of basic ClO− promoted the exothermic reaction. Based on the results, acidity has a strong impact on the reaction behaviour.

There has been considerable evidence that natural disasters can be threats to technological systems and when these threats are concomitant, they pose tremendous risks to countries and communities. Such risk (termed Natech risk) should be incorporated early in the design process, particularly in land-use planning of sites. In this study, a descriptive classification of Natech risk sources was developed, mainly from analysis of a Japanese database, to contribute to preliminary analysis of Natech risk. Analysis of the information gathered, resulted in a classification including fifteen physical effects and six physical impacts that cause technical disorder. Here, the pertinent aspects of natural hazards were termed physical effects, and the phenomena caused by physical effects were termed physical impacts: the primary observable consequences and influences on the functions of technological systems. The classification is expected to be helpful for Natech risk identification, by providing guidewords useful for risk assessment and management.

The objective of this study is to obtain information about the thermal decomposition behaviors of hydrazine (N 2 H 4 ) caused by metals, using differential scanning calorimeter (DSC) and SuperCRC. The DSC measurements revealed that the exothermic reactions of N 2 H 4 were caused by the reaction conditions such as the type of cells; the T DSC with a gold pan is 485.2 K and that with a glass capillary is 620.5 K. Besides, the activation energy of the thermal decomposition of N 2 H 4 , calculated from the Kissinger and Ozawa methods, were found to be about 38±2 kJ mol −1 in the gold pan and 141±8 kJ mol −1 in the glass capillary. Moreover, a heat flow profile was observed with SuperCRC during the mixing of N 2 H 4 and the metal ion solution at 298 K. The maximum heat flow was related to the metal ion oxidative characters. The higher oxidative characters would provide a faster acceleration for the exothermic behavior than the lower oxidative ions. Based on this study, Mn(VII) and Cr(VI) were considered to exhibit strongly oxidative characteristics during mixing with N 2 H 4 .

On the Metropolitan Expressway in Tokyo, a tank car exploded because it was carrying hydrogen peroxide (H2O2) in a compartment in which copper chloride (CuCl2) remained. Although the main cause of the accident was trivial, the background on the accident suggested that an induction period in the reaction led to a mistake. This report describes the experimental investigation of the catalytic ability of CuCl2, and comparing it with two other copper(II) compounds (nitrate: Cu(NO3)2; and copper sulfate: CuSO4) and three iron(III) compounds (chloride: FeCl3; nitrate: Fe(NO3)3; and sulfate: Fe2(SO4)3). The experiments were performed using a reaction calorimeter. During the experiments at 35 °C, 2×10−5 mol of copper compounds slowly reacted with H2O2 and generated a precipitate. The iron compounds allowed the hydrogen peroxide to violently decompose. A 1×10−4 mol solution of CuCl2, however, produced a violent decomposition at 35 °C. At 15 °C, a moderate heat release occurred. Based on these results, the concentration and temperature dependence of the catalytic ability of CuCl2 were postulated to contribute to the induction period observed in the accident.

The objective of this study is to obtain information on the calorimetric behaviors of aqueous solutions of hydroxylamine (HA), hydroxylamine chloride (HACl), and hydroxylamine nitrate(HAN) caused by different Fe(III) states (free Fe(III) from Fe(NH 4 )(SO 4 ) 2 , Fe(CN) 6 3− , and Fe(EDTA) − ). The calorimetric data were obtained with a small-scaled reaction calorimeter, Super-CRC. In the mixing with Fe(III), HA showed the highest reactivity among three substrates. Free Fe(III) and Fe(EDTA) − showed catalytic effects in the reactions. In the overall heat of reactions, Fe(EDTA) − exceeded free Fe(III), which precipitated as Fe(OH) 3 and decreased the chances of interactions with HA. It was suggested that the generation of NH 3 had taken place in the process of reducing HA along with Fe(II) oxidation. Fe(CN) 6 3− was less reactive than free Fe(III) and Fe(EDTA) − . The ability of masking Fe(III) was estimated for CyDTA. The HA including CyDTA had no exothermic peak; however, there was an endothermic peak of the heat flow at Fe(III) injection. CyDTA was found to have the ability to inhibit a violent exothermic reaction of HA.