Current Microwave Chemistry (Volume 11 - Issue 2)

A Decade of Advancement in Ruthenium (II)-Catalyzed Direct C-H Activation and Consequent C-C/C-N Bond Formation Using Microwave Heating

2024-09-26

Transition-metal catalysed activation of unreactive C-H bonds and subsequent C-C bond formation has emerged as a principal and essential tool in the field of synthetic organic chemistry. On the other hand, the microwave heating technique has been intensively used to carry out organic transformation of almost all kinds and has become a promising non-conventional technique for performing synthetic reactions. Direct C-H activation for C-C bond-forming reactions using ruthenium as a catalyst is currently a hot topic and represents a cost-effective synthetic pathway in organic chemistry which is accompanied by the advantages of MW irradiation resulting in shorter reaction time and greener as well as sustainable accomplishments.

Green Synthesis of Thiazoles and Thiadiazoles having Anticancer Activities under Microwave Irradiation

2024-09-26

Sulfur and nitrogen-containing heterocycles have received a great deal of attention due to their unique structures and therapeutic relevance. Thiazoles and thiadiazoles are important fivemembered heterocycles containing sulfur and nitrogen atoms that draw the special attention of researchers due to their synthetic diversity and potent pharmacological properties. Thiazoles and thiadiazoles are used in agrochemicals, liquid crystals, sensors, the cosmetic industry, cyanine dyes, etc. Sometimes, organic synthesis, including thiazoles and thiadiazoles syntheses with the help of conventional methods, is laborious work, while synthesis of promising organic molecules using microwave irradiation provides better yields, diminishes the reaction time, and reduces unwanted side products. The major causes of death worldwide are due to cancer. Current research demands the design and preparation of novel compounds, including thiazoles and thiadiazoles, that may help to combat cancer, as chemotherapy or chemo drugs suffer from some demerits, including toxicity, lack of selectivity, resistance, and side effects. Hence, the review focuses on the microwave-assisted synthesis of thiazoles and thiadiazoles as a sustainable technique for the first time, and it also aims to highlight the anticancer activities of thiazoles and thiadiazole derivatives elegantly.

Microwave Revolution: Transforming Biomedical Synthesis for Tissue Engineering Advancements

2024-09-26

Microwave-Assisted Synthesis (MAS) has emerged as a groundbreaking technique revolutionizing the field of biomedical and tissue engineering. This review aims to explore the fundamental principles, techniques, and applications of MAS in these domains. Beginning with an overview highlighting its significance, we delve into the basic principles, mechanisms, and comparative analysis with conventional methods. Subsequently, the review explores MAS techniques in biomaterial synthesis, tissue scaffold fabrication, functionalization, and nanomaterial synthesis, along with their role in drug delivery systems. We then examine its diverse applications, including rapid biomaterial synthesis, property tailoring, biocompatibility enhancements, and tissue regeneration strategies. Furthermore, we address the challenges and future perspectives, focusing on safety considerations, understanding cellular responses, integration with advanced technologies, regulatory aspects, and future directions. This comprehensive review underscores MAS as a transformative tool driving innovations in biomedical research and therapeutic applications.

Microwave Thermal Treatment for the Recovery of Re in Copper and Molybdenum Concentrates

2024-09-26

Background: Rhenium (Re) is obtained as a by-product during the extraction of copper and molybdenum ores. In current extractive metallurgy, Re extraction involves a heat treatment that causes Re losses by volatilization and release of toxic gases into the environment.

Objective: This research proposes a novel microwave heat treatment (MWHT) to enhance Re extraction avoiding Re losses and toxic gas release into the environment.

Methods: A novel MWHT and traditional thermal processes used in mining were applied to Cu- Mo concentrates. The elemental composition analysis of the concentrate was performed by atomic spectrometry. The crystalline phase was identified by X-ray diffraction. Particle structure observations were performed with an optical microscopy (OM) and scanning electron microscopy (SEM) with a Field Emission, including semiquantitative analysis (EDS). Thermal behavior and non-isothermal reduction processes were studied using Thermogravimetry Differential Thermal Analysis (TG-DTA).

Results: Re, S and As release decreased 5% during MWHT, compared to 34% of traditional methods. Molybdenite (MoS₂) and Chalcopyrite (CuFeS₂) were the crystalline phases in the ore after MWHT. Rhenium was found as an oxide (ReO₃) and metallic Re. Samples under MWHT showed structural transformations in the mineral particles, with minimal mass losses and high Re and Mo concentrations. The structural transformation of the ore involved microcracks formation.

Conclusion: The MWHT induces a combination of particle degradation mechanisms and lower temperature requirements that prevent Re losses. Lower gas emissions turn this technology into an environmentally friendly one. Crystalline transformation of the Re-chalcopyrite phase enhances Re release during leaching, the next step after MWHT in the hydrometallurgical extraction.

Acknowledgement to Reviewers

2024-09-26