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Cao, E., Zuburtikudis, I., Al-Rifai, N., Roydhouse, M., & Gavriilidis, A. (2014). Enhanced Performance of Oxidation of Rosalva (9-decen-1-ol) to Costenal (9-decenal) on Porous Silicon-Supported Silver Catalyst in a Microstructured Reactor. Processes, 2(1), 141-157., The use of metal-assisted HF chemical etching as a convenient technique to produce a few microns thick porous layer in silicon microchannels was demonstrated. Gas phase selective oxidation of rosalva to its aldehyde (costenal) was performed in glass/silicon microstructured reactors at temperatures of 375–475 °C on silver catalyst which was deposited on both porous and flat silicon surface by sputter-coating. The effects of temperature (375–475 °C), rosalva concentration (1.17%–3.43%), O2 to rosalva ratio (0.5–20) and residence time on the reaction were investigated. The reactivity of rosalva on the porous silicon supported silver was 5.7–6.4 times higher than on the thin film silver catalyst at 450 °C. Furthermore, activation energy for the porous silicon supported silver was lower. Isothermal conditions in the microreactors allowed high conversion and selectivity to be achieved in a wide range of temperature and oxygen concentration. At typical reaction conditions (1.75% rosalva, O2/rosalva = 3, residence time 18 ms and 450 °C), conversion of 97% and selectivity of 95% to costenal was achieved, corresponding to a turnover frequency of 268 h−1.

Microreaction technology is an interdisciplinary field that has gained significant momentum in recent years due to the numerous advantages it offers compared to conventional systems in terms of enhanced heat and mass transfer and safer operation. The experimental efficiency achieved through the well-defined conditions offered by microchannel reactors has been utilised to elucidate intrinsic reaction kinetics, often in reaction spaces that were previously unexplored. In this review, we discuss prospects for advancing catalytic process development by combined application of microstructured flow reactors with techniques for in situ catalyst characterisation and mathematical optimisation.

Microbubbles have the potential to be used in many applications in different fields, especially in food, biomedical, and environmental sciences. However, to produce microbubbles with relatively long-term stability is difficult as they are inherently unstable entities. Hydrophobins are naturally occurring proteins that have previously been shown to have an ability to stabilize micron-sized air cells. More recently, small air cells with other cysteine-rich proteins such as bovine serum albumin and egg albumen (egg white protein) have been constructed using a sonochemical method. The majority of the air cells had a diameter between 1 and 10 μm. A dependence of the air cell size and stability with the processing conditions and concentration were found. The air cells’ shells are dense enough to form a cage-like structure around air cells and are equally as robust as those from hydrophobins.

Despite the great industrial importance of benzaldehyde as a reaction intermediate, only a few attempts have been made in the literature to develop kinetic models able of characterising the catalytic oxidation of benzyl alcohol to benzaldehyde quantitatively both in batch and flow systems. The purpose of this paper is to merge the information obtained from a laboratory scale batch glass stirred reactor (GSR) with the information obtained from a continuous-flow micro-packed bed reactor (MPBR) for an accurate and quantitative description of the products distribution in these reaction systems. A two-stage procedure is applied for this purpose where experimental design techniques are used for evaluating the most promising regions of the experimental space for the identification of kinetic models.

Microreactor platforms represent advanced tools in reaction engineering for the quick development of reliable kinetic models. Experiments can be performed with a better reaction temperature control, enhanced heat and mass transfer and mixing of reactants. However, the effectiveness of the model identification procedure is strictly related to the execution of properly designed experiments, allowing elucidation of the reaction mechanisms and providing a precise estimation of the kinetic parameters. In this paper a model-based design of experiments (MBDoE) approach is proposed where experiments are designed for both discriminating among competing models and for improving the estimation of kinetic parameters. The procedure is tested on a real case study related to the identification of kinetic models of methanol oxidation on silver catalyst.

Anodically bonded etched silicon microfluidic devices that allow infrared spectroscopic measurement of solutions are reported. These extend spatially well-resolved in situ infrared measurement to higher temperatures and pressures than previously reported, making them useful for effectively time-resolved measurement of realistic catalytic processes. A data processing technique necessary for the mitigation of interference fringes caused by multiple reflections of the probe beam is also described.

An experimental and theoretical study of capillary gas/liquid phase microseparators is presented. The device studied comprises a main microchannel with a set of capillaries fabricated to each side so that the liquid (wetting) phase can be separated from the gas (non-wetting) phase due to capillary effects. Different units are employed with different characteristics of capillaries (constant or tapered cross-sectional area and capillary size). We study how complete separation depends on the externally controlled pressure difference at the liquid and the gas outlet and how separation is affected by the imposed inlet flow rate. The results demonstrate that the operability pressure window becomes narrower as the fluid flow rates increase, and reveal discrepancies with theoretical predictions based on a simple Hagen–Poiseuille formulation. This is addressed by a new equation that takes into account interface curvature effects, and is found to be in qualitative agreement with the experimental results. In addition, we perform CFD simulations observing the emergence of interface breaking at high flow rates.