Increased flammability hazard when ionic liquid [C6mim][Cl] is exposed to high temperatures

Electrochemical Modulation of the Flammability of Ionic Liquid Fuels

Flammability and combustion of high energy density liquid propellants are controlled by their volatility. We demonstrate a new concept through which the volatility of a high energy density ionic liquid propellant can be dynamically manipulated enabling one to (a) store a thermally insensitive oxidation resistant nonflammable fuel, (b) generate flammable vapor phase species electrochemically by applying a direct-current voltage bias, and (c) extinguish its flame by removing the voltage bias, which stops its volatilization. We show that a thermally stable imidazolium-based energy dense ionic liquid can be made flammable or nonflammable simply by application or withdrawal of a direct-current bias. This cycle can be repeated as often as desired. The estimated energy penalty of the electrochemical activation process is only ∼4% of the total energy release. This approach presents a paradigm shift, offering the potential to make a "safe fuel" or alternatively a simple electrochemically driven fuel metering scheme.

Experimental Study of the Thermal Decomposition Properties of Binary Imidazole Ionic Liquid Mixtures

Ionic liquids (ILs) have a wide range of applications, owing to their negligible vapor pressure, high electrical conductivity, and low melting point. However, the thermal hazards of ILs and their mixtures are also non-negligible. In this study, the thermal hazards of various binary imidazolium ionic liquids (BIIL) mixtures were investigated. The effects of parent salt components and molar ratios on the thermal decomposition temperature (T_d) and flashpoint temperature (T_f) are investigated. It is found that both T_d and T_f increase as the proportion of highly thermally stable components in BIIL mixtures increases. Furthermore, the decomposition process of BIIL mixtures can be divided into two stages. For most molar ratios, the T_f of the BIIL mixtures is in the first stage of thermal decomposition. When the proportion of highly thermally stable components is relatively high, T_f is in the second stage of thermal decomposition. The flammability is attributed to the produced combustible gases during the thermal decomposition process. This work would be reasonably expected to provide some guidance for the safety design and application of IL mixtures for engineering.

Thermal, chemical, electrochemical, radiolytic and biological stability of ionic liquids and deep eutectic solvents

Ionic liquids (ILs) and deep eutectic solvents (DESs) are regarded as two kinds of novel solvents with high tunability and they exist in liquid-state for a wide range of temperature....

Fire and explosion hazards of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

The decomposition of [EMIM][Tf₂N] is endothermic in a nitrogen atmosphere but is exothermic in an air atmosphere.

Thermal hazards of benzoyl peroxide and its derived process products through theoretical thermodynamics assessment and different calorimetric technologies

Benzoyl peroxide (BPO) is one of the primary OPs used as an initiator, curing agent, or medicine. Some of the plastic processes use BPO without air for maintaining the efficiency of the entire reaction. However, there have been numerous accidents involving BPO in petrochemical plants, especially those related to fire and explosion, that are due to its unstable thermal properties and peroxy bond (OO). BPO can be identified as a typical substance with autocatalytic reaction characteristics. Therefore, the related processes and their products are critical to prevent these kinds of chemical contingencies. This research was based on two types of instruments (nonisothermal and isothermal calorimetry), and theoretical methods to further determine the thermal hazard level. From the experimental results for BPO and BPO mixed with its by-products, the heat of decomposition was much higher (from 800 to 1235 J/g), the time to maximum rate under isothermal conditions was much shorter (from 99.1 to 17.4 h at 75.0 °C), and the apparent activation energy was much lower (from 118 to 91 kJ/mol) after BPO was mixed with its by-products. Therefore, the hazard level of BPO mixed with its by-products from the reaction process was much higher than that of pure BPO.