Inductive heating and flow chemistry - a perfect synergy of emerging enabling technologies

Induction Heating for the Electrification of Catalytic Processes

The increasing availability of electrical energy generated from clean, low-carbon, renewable sources like solar and wind power is paving the way for a more sustainable future. This has resulted in a growing trend in the chemical industry to increase the share of electricity use in chemical processes, particularly catalytic ones. This shift towards electrifying catalytic processes offers significant environmental benefits. Current practices rely heavily on fossil fuel-based burners, primarily using natural gas, which contribute significantly to greenhouse gas emissions. Therefore, replacing fossil fuels with electricity can significantly reduce the carbon footprint associated with chemical production. Additionally, the energy-intensive production of metal catalysts used in these processes further exacerbates the environmental impact. This review focuses on the electrification of chemical processes, particularly using induction heating (IH), as a method to reduce the environmental impact of both catalyst production and operation. IH shows promise compared to conventional heating methods, since it offers a cleaner, more efficient, and precise way to heat catalysts in chemical processes by directly generating heat within the catalyst itself. It can potentially even enhance the reaction performance through its influence on the reaction mechanism. By exploring recent advancements in IH-driven catalytic processes, the review delves into how this method is revolutionizing catalysis by enhancing performance, selectivity, and sustainability. It highlights recent breakthroughs and discusses perspectives for further exploration in this rapidly developing field.

Are activation barriers of 50-70 kcal mol-1 accessible for transformations in organic synthesis in solution?

High-temperature organic chemistry represents a transformative approach for accessing reaction pathways previously considered unattainable under conventional conditions. This study focuses on a high-temperature synthesis as a powerful method for performing solution-phase organic reactions at temperatures up to 500 °C. Using the isomerization of N-substituted pyrazoles as a model reaction, we demonstrate the ability to overcome activation energy barriers of 50-70 kcal mol-1, achieving product yields up to 50% within reaction times as short as five minutes. The methodology is environmentally friendly, leveraging standard glass capillaries and p-xylene as a solvent. The significance of high-temperature synthesis lies in its simplicity, efficiency, and ability to address the limitations of traditional methods in solution chemistry. Kinetic studies and DFT calculations validate the experimental findings and provide insights into the reaction mechanism. The method holds broad appeal due to its potential to access diverse compounds relevant to pharmaceuticals, agrochemicals, and materials science. By expanding the scope of accessible reactions, this exploration of experimental possibilities opens a new frontier in synthetic chemistry, enabling the exploration of previously inaccessible transformations. This study establishes a new direction for further innovations in organic synthesis, fostering advancements in both fundamental research and practical applications.

Magnetically induced localized heating enabling rapid and efficient synthesis of metal-organic frameworks

We demonstrate magnetic induction heating (MIH) with superparamagnetic iron oxide nanoparticles (IONPs) as a new rapid and energy-efficient methodology for synthesizing metal-organic frameworks (MOFs). Acting as localized heat sources, these IONPs overcome the energy losses associated with traditional solvothermal synthesis, which enables a fast, uniform, and highly energy-efficient heat transfer process. The versatility of this method is illustrated for the successful synthesis of three different benchmark MOFs in good yields with high crystallinity.

Cobalt ferrite as an electromagnetically boosted metal oxide hetero-Fenton catalyst for water treatment

The cobalt ferrite Fenton catalysts were obtained by the flow co-precipitation method. FTIR, XRD, and Mössbauer spectroscopy confirmed the spinel structure. The crystallite size of the as-synthesized sample is 12 nm, while the samples annealed at 400 and 600 °C have crystallite sizes of 16 and 18 nm, respectively. The as-synthesized sample has a grain size of 0.1-5.0 μm in size, while the annealed samples have grain sizes of 0.5 μm-15 μm. The degree of structure inversion ranges from 0.87 to 0.97. The catalytic activity of cobalt ferrites has been tested in the decomposition of hydrogen peroxide and the oxidation of caffeine. The annealing of the CoFe₂O₄ increases its catalytic activity in both model reactions, with the optimal annealing temperature being 400 °C. The reaction order has been found to increase with increasing H₂O₂ concentration. Electromagnetic heating accelerates the catalytic reaction more than 2 times. As a result, the degree of caffeine decomposition increases from 40% to 85%. The used catalysts have insignificant changes in crystallite size and distribution of cations. Thus, the electromagnetically heated cobalt ferrite can be a controlled catalyst in water purification technology.

Research Progress on Magnetic Catalysts and Its Application in Hydrogen Production Area

The noncontact heating technology of IH targets heat directly where it is needed through the electromagnetic energy adsorption and conversion of magnetic materials. Unlike conventional heating methods, the heat generated by electromagnetic induction of magnetic materials can be applied directly into the reactor without heating the entire device; this new heating method is not only more energy efficient but also safer, cleaner and more sustainable if renewable electricity is adopted; moreover, magnetic catalysts can be recovered and reused by separating chemical reactants and products from the catalyst by the application of a magnetic field, and it can provide the required heat source for the reaction without altering its catalytic properties. Magnetic catalysts with an electric field have been applied to some industrial areas, such as the preparation of new materials, catalytic oxidation reactions, and high-temperature heat absorption reactions. It is a trend that is used in the hydrogen production process, especially the endothermic steam reforming process. Therefore, in this paper, the heat release mechanism, properties, preparation methods and the application of magnetic catalysts were presented. Highlights of the application and performance of magnetic catalysts in the hydrogen production area were also discussed.