While researchers have extensively studied the initial decomposition mechanism of Monomethylhydrazine (MMH, CH₃NHNH₂) in the MMH/dinitrogen tetroxide (NTO) system, the investigation of Unsymmetrical Dimethylhydrazine (UDMH, (CH₃)₂NNH₂) has been limited due to its high toxicity, corrosiveness, and deterioration rate. Hence, the effects of UDMH’s deterioration products on combustion performance and gas-phase combustion reaction mechanisms remain unclear. This comprehensive review examines the existing research on the reaction kinetics of the three widely used hydrazine-based self-ignition propellants: Hydrazine (HZ, N₂H₄): MMH: and UDMH, emphasizing the necessity for further investigation into the reaction kinetics and mechanisms of UDMH. It also discusses the implications of these findings for developing safer and more efficient rocket propulsion systems. Additionally, this review underscores the importance of utilizing computational chemistry theory to analyze hydrazine-based fuels’ combustion and decomposition properties, constructing detailed pyrolysis and combustion reaction mechanisms to optimize rocket engine fuel performance and environmental concerns.

Double emulsions with ultrathin shells are important in some biomedical applications, such as controlled drug release. However, the existing production techniques require two or more manipulation steps, or more complicated channel geometry, to form thin-shell double emulsions. This work presents a novel microfluidic tri-phasic step-emulsification device, with an easily fabricated double-layer PDMS channel, for production of oil-in-oil-in-water and water-in-water-in-oil double emulsions in a single step. The shell thickness is controlled by the flow rates and can reach 1.4% of the μm-size droplet diameter. Four distinct emulsification regimes are observed depending on the experimental conditions. A theoretical model for the tri-phasic step-emulsification is proposed to predict the boundaries separating the four regimes of emulsification in plane of two dimensionless capillary numbers, Ca. The theory yields two coupled nonlinear differential equations that can be solved numerically to find the approximate shape of the free interfaces in the shallow (Hele-Shaw) microfluidic channel. This approximation is then used as the initial guess for the more accurate finite element method solution, showing very good agreement with the experimental findings. This study demonstrates the feasibility of co-flow step-emulsification as a promising method to production of double (and multiple) emulsions and micro-capsules with ultrathin shells of controllable thickness.

Trimethyl Phosphate (TMP), an organophosphorus liquid compound, is valued for its versatile qualities and applications in various fields. In modern chemical research and industry, processes involving Trimethyl Phosphate are optimized for minimal negative environmental impact, and scientific advancement is driven by adherence to stringent regulations to provide sustainable solutions and resource preservation. Thermochemical insights enhance our understanding of monomer incorporation, initiation, and propagation energetics. This study comprehensively investigates the thermochemistry and rate kinetics that govern H-atom abstractions in TMP through advanced computational techniques. The theoretical framework encompasses methodologies for conducting conformer searches, exploring transition states, and performing energy calculations. This study calculates rate constants for eight H-atom abstraction reactions involving TMP with stable species, O-2 (oxygen), H (hydrogen), and radicals [H (hydroxyl), & Cdot;H-3 (methyl), CH3 (methoxy), H-2 (hydroperoxyl), H-2 (amino), and & Cdot;N (cyano)], and further analogies are related to barrier heights. Bond dissociation energies are also determined, highlighting TMP's susceptibility to various reaction pathways. The discussion and findings elucidate the need for further experimental validation for practical applications of TMP in chemical synthesis, combustion, flame-retardant technologies, environmental processes, and pharmaceutical research.