Hazard Potential of Decomposition Reactions Using the Example of Hydrogen Peroxide (H2O2)

Hydrogen Peroxide

Pure hydrogen peroxide (H2O2) is a pale blue liquid, mixable in any ratio with water. Low-percentage aqueous solutions are widely used as bleaching agents due to their strong oxidizing properties. Besides for the bleaching of wood, paper or hair, hydrogen peroxide solutions are also used as oxidizing agents or in medical application as disinfectants. The tendency of hydrogen peroxide to decompose into water and oxygen (see equation 1 below) is the reason for its application as a liquid propellant in rocket engines.

(equation 1)

Multiple Module Calorimeter (MMC)

The NETZSCH Multiple Module Calorimeter Multiple Module Calorimeter (MMC)A multiple mode calorimeter device consisting of a base unit and exchangeable modules. One module is prepared for accelerating rate calorimetry (ARC®), the ARC®-Module. A second one is used for scanning tests (Scanning Module) and a third one is related to battery testing for coin cells (Coin Cell Module).MMC 274 Nexus® (figure 1) offers three different measurement modules [1]. The Accelerating Rate Calorimetry (ARC)The method describing isothermal and adiabatic test procedures used to detect thermally exothermic decomposition reactions.ARC® Module can be used for thermal hazard studies; the Coin-Cell Module is specialized for the investigation of batteries; and the Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module can be used to evaluate caloric data from a single heating run. In contrast to the widely used and well-known technique of differential scanning calorimetry (DSC), the Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module of the Multiple Module Calorimeter (MMC)A multiple mode calorimeter device consisting of a base unit and exchangeable modules. One module is prepared for accelerating rate calorimetry (ARC®), the ARC®-Module. A second one is used for scanning tests (Scanning Module) and a third one is related to battery testing for coin cells (Coin Cell Module).MMC can handle samples up to a volume of 2 ml. For heating the samples, there are two options available: either a constant heating rate or a constant level of power. By using information about both the power supplied to the sample and the heating rate, a heat-flow signal can be calculated. Using metals such as indium, tin and bismuth, both the temperature and the sensitivity of the instrument can be determined. At 1000 to 9000 mg (sample volume about 1 ml), typical sample masses are considerably higher for the Multiple Module Calorimeter (MMC)A multiple mode calorimeter device consisting of a base unit and exchangeable modules. One module is prepared for accelerating rate calorimetry (ARC®), the ARC®-Module. A second one is used for scanning tests (Scanning Module) and a third one is related to battery testing for coin cells (Coin Cell Module).MMC than sample masses used for DSC, which are typically between 5 and 10 mg. Even so, the evaluated uncertainty for the Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module of the Multiple Module Calorimeter (MMC)A multiple mode calorimeter device consisting of a base unit and exchangeable modules. One module is prepared for accelerating rate calorimetry (ARC®), the ARC®-Module. A second one is used for scanning tests (Scanning Module) and a third one is related to battery testing for coin cells (Coin Cell Module).MMC is about 1% for temperature determinations and less than 5% for enthalpy determinations.

This work studies the thermal Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition behavior of hydrogen peroxide (35%) employing two Multiple Module Calorimeter (MMC)A multiple mode calorimeter device consisting of a base unit and exchangeable modules. One module is prepared for accelerating rate calorimetry (ARC®), the ARC®-Module. A second one is used for scanning tests (Scanning Module) and a third one is related to battery testing for coin cells (Coin Cell Module).MMC modules, the Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module (see figure 2) and the Accelerating Rate Calorimetry (ARC)The method describing isothermal and adiabatic test procedures used to detect thermally exothermic decomposition reactions.ARC® Module (see figure 3). Via an external heater which directly surrounds the sample vessel (figure 4), the Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module can provide the sample with a constant level of power.

1) NETZSCH Multiple Module Calorimeter (MMC)A multiple mode calorimeter device consisting of a base unit and exchangeable modules. One module is prepared for accelerating rate calorimetry (ARC), the ARC-Module. A second one is used for scanning tests (Scanning Module) and a third one is related to battery testing for coin cells (Coin Cell Module).MMC 274 Nexus®

Comparison of the Behavior of H2O2, H2O and Empty Vessel

The results in figure 5 present exclusively the sample heating. Since the Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition reaction of hydrogen peroxide is not reversible, the oxygen generated is not taken up again in order to form the initial hydrogen peroxide during cooling. Instead, the formed products of water and oxygen cool to ambient temperature as a liquid and a gas, respectively. The pressure signal indicates 17.7 bar at 40°C, which reflects the amount of oxygen being formed during Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition (figure 6). Taking the same amount of water instead, the pressure also increases during heating, but since water remains chemically unchanged, all water vapor precipitates again during cooling. That’s why the dashed blue line, indicating the pressure signal for water during cooling, shows values almost identical to the heating (solid lines). Just for comparison, the green lines show the course of the pressure signal during heating and cooling for an empty vessel.

5) Results of thermal Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition of hydrogen peroxide (35%); temperature (red), pressure (blue) and heating rate (black)
6) Results of heating and cooling of hydrogen peroxide (35%, red), water (blue) and empty vessel (green). Heating is shown with solid lines, cooling with dashed lines.

Advantages of the Scanning Module

These results obtained by the Multiple Module Calorimeter (MMC)A multiple mode calorimeter device consisting of a base unit and exchangeable modules. One module is prepared for accelerating rate calorimetry (ARC), the ARC-Module. A second one is used for scanning tests (Scanning Module) and a third one is related to battery testing for coin cells (Coin Cell Module).MMC Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module clearly demonstrate that the discontinuous course of the heating rate along with the pressure build-up are excellent indicators for hazard potential in terms of Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition reactions or ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermic reactions. Even a small power level such as 250 mW, resulting in a comparably small heating rate of approximately 1 K/min, the heating for this exemplary measurement takes less than 4 hours. Therefore, the MMC Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module is well suited to be used as a screening tool. In cases where pressure and/ or temperature increase are detected, an AdiabaticAdiabatic describes a system or measurement mode without any heat exchange with the surroundings. This mode can be realized using a calorimeter device according to the method of accelerating rate calorimetry (ARC®). The main purpose of such a device is to study scenarios and thermal runaway reactions. A short description of the adiabatic mode is “no heat in – no heat out”.adiabatic test should be the next step.

Accelerating Rate Calorimetry

Specialized calorimeters allow for sample investigation in accordance with the method of accelerated rate calorimetry (ARC®). An ARC®-type equipment offers an AdiabaticAdiabatic describes a system or measurement mode without any heat exchange with the surroundings. This mode can be realized using a calorimeter device according to the method of accelerating rate calorimetry (ARC®). The main purpose of such a device is to study scenarios and thermal runaway reactions. A short description of the adiabatic mode is “no heat in – no heat out”.adiabatic sample environment in order to not allow any heat exchange and to detect even the smallest of self-heating reactions. The typical measurement mode is called heatwait-search (Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).HWS). The sequence of heating, equilibration and detection of even the smallest of self-induced temperature changes is a quasi-IsothermalTests at controlled and constant temperature are called isothermal.isothermal approach used in order to determine the temperature at which the Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition reaction starts. A diagram depicting Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).heat-wait-search is shown in figure 7. 

A cross-section of the MMC’s ARC® Module set-up is depicted in figure 3. If the Self-heating rateA special kind of calorimeter device is used in order to detect the self-heating rate of a substance. The related method is called accelerating rate calorimetry (ARC®). self-heating rate of 0.02 K/min is exceeded during the detection period (search), the measurement changes from Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).heat-wait-search to AdiabaticAdiabatic describes a system or measurement mode without any heat exchange with the surroundings. This mode can be realized using a calorimeter device according to the method of accelerating rate calorimetry (ARC). The main purpose of such a device is to study scenarios and thermal runaway reactions. A short description of the adiabatic mode is “no heat in – no heat out”.adiabatic mode. This means the surrounding heaters (top, side and bottom) no longer follow the above-mentioned sequence, but rather track the sample temperature. During this “AdiabaticAdiabatic describes a system or measurement mode without any heat exchange with the surroundings. This mode can be realized using a calorimeter device according to the method of accelerating rate calorimetry (ARC). The main purpose of such a device is to study scenarios and thermal runaway reactions. A short description of the adiabatic mode is “no heat in – no heat out”.adiabatic” mode, there is no temperature difference and thus no heat exchange between the sample and the calorimeter environment.

7) Sequence of the Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).heat-wait-search (Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).HWS) measurement mode

H2O2 in the ARC® Module

Figure 8 depicts the results of the Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition of hydrogen peroxide (35%) investigated with the MMC’s ARC® Module employing the Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).heat-wait-search mode. The temperature increment in the stepwise heating was 10 K and the system was allowed to stabilize for 30 minutes during the wait segment. The answer to the question of whether or not an ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermic event is detected during the 10-minute search period depends on the ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermic threshold. Between 40°C and 70°C, self-heating during the search period was less than 0.02 K/min and the heatwait-search sequence continued. At 80°C, the detected self-heating had exceeded that threshold and the calorimeter thus changed over to the adiabatic mode. The temperature increase (ΔTobs) was detected to be 41.5 K. Taking Thermal inertiaThe thermal inertia is equivalent to the PHI-factor. Both describe the ratio of mass and specific heat capacity of a sample or sample mixture compared to that of the vessel or sample container.thermal inertia [1] into account, the adiabatic temperature increase is calculated to be 94.9 K (ΔTad). The difference is based on the so-called PHI-factorThe PHI-factor (Φ) is equivalent to the thermal inertia. Both describe the ratio of mass and specific heat capacity of a sample or sample mixture compared to that of the vessel or sample container. PHI-factor which is mainly given by the ratio of mass times Specific Heat Capacity (cp)Heat capacity is a material-specific physical quantity, determined by the amount of heat supplied to specimen, divided by the resulting temperature increase. The specific heat capacity is related to a unit mass of the specimen.specific heat capacity of the container versus mass times Specific Heat Capacity (cp)Heat capacity is a material-specific physical quantity, determined by the amount of heat supplied to specimen, divided by the resulting temperature increase. The specific heat capacity is related to a unit mass of the specimen.specific heat capacity of the sample. In addition to the increase in temperature caused by self-heating of the sample during Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition, the pressure increase can also be quantified. At the end of the adiabatic segment, the increase in pressure was more than 20 bar.

8) Results for the Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition behavior of hydrogen peroxide investigated with the MMC’s ARC® Module and Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).heat-wait-search (Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC®).HWS) mode

Conclusion

The Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition behavior of a 35% aqueous hydrogen peroxide solution was investigated with the MMC’s Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module as well as with its ARC® Module. Since the Scanning ModuleA calorimeter module being part of the Multipe Module Calorimeter (MMC) allowing for scanning test of a sample. This procedure can serve as a screening test in order to detect a thermal hazard potential within a reasonably short measurement time.Scanning Module is operated using either a constant level of power (as was the case here) or a constant heating rate, these experiments are far less time-consuming than with the Heat-Wait-Search (HWS)Heat-Wait-Search is a measurement mode used in calorimeter devices according to accelerating rate calorimetry (ARC).heat-wait-search method. Therefore, the Scanning Module is an excellent screening tool for investigating unknown samples with respect to self-Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition or hazardous potential. In cases where an investigated sample exhibits unsteady temperature behavior during the scanning run, or in cases where a Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. decomposition reaction is indicated by pressure build-up, any further investigation on the samples should be carried out using ARC®-type equipment. Values such as pressure build-up as well as observed and Adiabatic temperature riseThe adiabatic temperature rise (delta Tad) is the observed temperature rise (delta Tobs) of a self-heating decomposition reaction under adiabatic conditions in consideration of the PHI-factor.adiabatic temperature rise are extremely important in assessing the hazardous potential of chemicals and can easily be obtained using the NETZSCH Multiple Module Calorimeter MMC 274 Nexus®.

Literature

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    E. Füglein, S. Schmölzer, “Epoxy Curing Investigated by Means of the DSC 214 Polyma and MMC 274 Nexus®“, NETZSCH Application Note 130, 2019
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    E. Füglein, “Screening of Hydrogen Peroxide Solutions by Means of Scanning and ARC® Tests”, NETZSCH Application Note 132, 2019