No abstract

Methyl methacrylate (MMA) as a specialty monomer of polymers has motivated industry to develop clean and sustainable technologies for its production. Herein, a comprehensive thermodynamic analysis of MMA production from petroleum-based and coal/biomass-based resources is conducted through the Gibbs free energy minimization method.For the petroleum-based route via oxidative esterification of methacrolein (MAL), the production of MMA is sensitive to the composition of methanol (MeOH) and O2 in the feed, but insensitive to the reaction temperature and pressure. For the coal/biomass-based route via aldol condensation of methyl acetate (MeOAc), the medium temperature (350-400 o C) and large MeOH/MeOAc ratio (>2) give rise to the efficient production of MMA. Hence, significant improvements in the MMA yield could be achieved by optimizing the reaction conditions, which could almost reach the maximal value theoretically of 1.0 mol from per mole of MAL or MeOAc. This study would shed new lights on the thermodynamics of MMA production, which paves a foundation for the development of new process at the industrial scale.

Myocardial infarction (MI) is the leading cause of death worldwide and can lead to the loss of cardiac function and heart failure. Reactive oxygen species (ROS) play a key role in the pathological progression of MI. The levels and effects of ROS are significantly different in three unique pathological stages of MI, and most antioxidants cannot make corresponding adjustments to eliminate ROS, which leads to a great compromise to treat MI with antioxidants. Herein, an innovative self-sustaining antioxidant strategy is developed to treat MI with self-sustaining selenium-embedded nanoparticles (SSSe NPs). SSSe NPs possess unique self-sustaining antioxidant effects at different pathological stages of MI. This strategy of on-demand ROS elimination during different pathological stages demonstrated excellent MI treatment efficacy and effectively reversed heart failure to normal heart function. The therapeutic mechanism of SSSe NPs is intensively investigated through a series of experiments and mainly involved five critical aspects of myocardial repair: protecting mitochondria, reducing cardiomyocyte apoptosis and ferroptosis, reducing inflammation and fibrosis, and promoting angiogenesis. This strategy not only provides a promising treatment option for MI but also offers inspiration for other ischemic diseases.