ACS Engineering Au最新文献

Crystallization is a crucial process in the purification of active pharmaceutical ingredients (APIs). Achieving controlled and efficient crystal formation is vital in successful production for industrial applications. This study investigates the crystallization of paracetamol using a model system, focusing on two techniques: ultrasound cavitation (UC) and hydrodynamic cavitation (HC). The role of cavitation in enhancing crystallization is well-established by using ultrasound. However, the crystallization process utilizing HC, especially in the absence of an antisolvent, is not investigated. A detailed investigation is still necessary to understand the nucleation process at the molecular level. This work primarily focuses on forming paracetamol crystals in an aqueous medium without the need for an antisolvent in HC. To address the nucleation study at the molecular level, the quartz crystal microbalance with dissipation (QCM-D) technique was employed to explore the nucleation kinetics of paracetamol crystallization while the solution is cooling. QCM-D allowed for real-time monitoring of mass changes and viscoelastic properties on the sensor surface, providing valuable insights into the adsorption, growth, and dissolution kinetics of paracetamol crystals under the influence of both cavitation techniques. The study revealed distinct crystallization behaviors depending on the type and intensity of cavitation, shedding light on the underlying mechanisms and potential implications for pharmaceutical manufacturing and formulation. These findings indicate that high-quality crystals can be produced using HC without the need for an antisolvent. This work highlights the significant potential for improving the efficiency and control of paracetamol crystallization and plays an important role in scaling up the crystallization process using HC.

The model-based scale-up of a homogeneously catalyzed Sonogashira coupling reaction is performed in a 3D printed metal continuous-flow reactor. The reaction is monitored with inline Raman spectroscopy with a low calibration effort, applying a multivariate curve resolution approach. Manufacturing conditions result in a space time yield of 412 kg m^–3 h^–1 and a productivity rate of 0.078 kg h^–1.

With the rapidly increasing use of fossil fuels, the exploration of various renewable energy sources has become critical. Among these, proton exchange membrane fuel cells (PEMFCs) are garnering significant attention as the next generation of green energy, which is ascribed to their ability to directly convert chemical energy into electricity without emitting pollutants. Specifically, the design and synthesis of effective catalysts are crucial in reducing the cost of commercial PEMFCs because the performance of the oxygen reduction reaction (ORR), which is the most critical reaction in PEMFCs, dictates the overall performance of the cell. Consequently, numerous research groups have recently focused on enhancing the performance and durability of the ORR catalysts. These improvements are being pursued in various fields, including geometry engineering and interfacial engineering. Efforts involve tuning the size and chemical composition of Pt catalysts, as well as developing diverse nanostructures that can be selectively positioned on the crystal surface or alloyed with transition metals. This review delves into the fundamentals of fuel cells and ORR catalysts, which are pivotal energy sources in the realm of green energy. It also outlines a series of catalyst synthesis strategies aimed at boosting their performance. Additionally, this paper offers new insights and highlights key considerations for the future development of platinum-based ORR catalysts in fuel cells.