V. Hessel

• Eindhoven University of Technology

In the present article, a new thermodynamic process is proposed in which a thermal plasma reactor is utilised to dissociate carbon dioxide/steam blend into synthetic fuel using chemical looping technology. Chrome/chrome oxide (Cr/Cr2O3) pair was used as the oxygen carrier and also the thermal transport medium between the thermal plasma reactor and...

In the present article, a new thermal plasma-aided process is proposed and analysed that utilises alumina/aluminium particles to dissociate steam/carbon dioxide blends into high-quality synthetic fuel. The proposed system utilises two reactors namely a synthetic fuel reactor and a thermal plasma particle regenerator following the chemical looping g...

In the pharmaceutical industry is genres large amounts of waste due to the multiple and complex purification steps needed. This was problem has urged the need for sustainable production pathways in the pharmaceutical industry. In this paper the use of ionic liquids to conduct automated purification is assessed by means of a Life Cycle Assessment. I...

In the present study, a series of thermochemical equilibrium modeling was conducted to assess the thermodynamic potential of biomass conversion to ammonia using thermal and nonthermal plasma at small‐ and large‐scale production. The system was designed and evaluated for five different locations in Australia including the Northern Territory, South A...

By using a multispecies fluid model, the tunability and controllability of plasma parameters such as distributions of electron density, electron energy, ion density, and electric field in a microdielectric barrier discharge (DBD) with a charge injector electrode and driven by negatively polarized nanosecond pulsed voltage superimposed on a positive...

In this perspective research article, we present a different take on the emerging issue of in-situ resource utilization (ISRU) through proposing technology disruption as solution for the engineering complex space systems. At the example of space chemical manufacturing, we consider microfluidic approaches as prime tool to achieve process intensifica...

In the present article, the thermodynamic potential of a sustainable plasma-assisted nitrogen fixation process for co-production of ammonia and hydrogen is investigated. The developed process takes advantage of chemical looping system by using a liquid metal such as gallium to drive nitrogen fixation reaction using three reactors including reactor...

In this paper precisely controlled silver nanoparticles synthesis method using microdroplets as a reactor was shown. It was confirmed that the application of microdroplets effects in a decrease in particles size and size distribution in comparison with a typical batch reactor from 4.8 ± 1.3 nm to 2.5 ± 0.5 nm. This decrease of particles size distri...

In this work, several kinetic models have been studied for the methanol dehydration to dimethyl ether (DME), applying a commercial ZSM-5 catalyst rather than state-of-the-art alumina. The kinetic tests were carried out in a fixed-bed external-recycle reactor, in the absence of temperature and concentration gradients. Kinetic parameters of the diffe...

Nitrogen fixation is gaining increasing interest owing to the essential role in the nitrogen cycle of the biosphere. Gliding arc based nitrogen fixation has great potential, especially for NOx synthesis, but the underlying mechanisms are poorly understood. This work presents an extensive study, elucidating the plasma chemistry by a combination of e...

Limitations with regard to the scalability of photochemical reactions can be efficiently overcome by using numbered-up microreactor technology. Here, the robustness of such a numbered-up capillary photomicroreactor system is tested when subjected to potential disturbances, such as channel blockage and light source failure. Channel blockage leads to...

FDA and pharmaceutical industry turn the vision of integrated end-to-end manufacturing currently into reality. Accordingly, besides the efforts to develop reactions in continuous flow, it is also essential to consider separation of reaction mixtures and purification of the desired product - and how these are best integrated into a process design. I...

A simulation model of biomass gasification for syngas production with steam as gasifying agent and subsequent syngas adjustment has been developed using Aspen Plus. The developed model is based on Gibbs free energy minimization applying the restricted equilibrium method. The objective is to study the effect of important parameters such as gasificat...

Solarbetriebene Durchflussreaktionen wurden mit einer innovativen, einem Laubblatt nachempfundenen Funktionseinheit basierend auf dem Konzept des lumineszierenden Solarkonzentrators (LSC) realisiert. In ihrer Zuschrift auf S. 1070 ff. demonstrieren M. G. Debije, T. Noël et al. die Fähigkeiten dieser Funktionseinheit, Photonen zu sammeln und spektra...

Hydrogen peroxide is considered as a green oxidant. However, H2O2 is industrially produced by the anthraquinone oxidation process, which is energy-intensive and not environmentally friendly. Therefore, more and more attention is attracted to the direct synthesis of H2O2 from hydrogen and oxygen. Microreactors can provide high mass and heat transfer...

Rufinamide is an antiepileptic drug used to treat the Lennox–Gastaut syndrome. It comprises a relatively simple molecular structure. Rufinamide can be synthesized from an organohalide in three steps. Recently we have shown that microreactor flow networks have better sustainability profiles in terms of life-cycle assessment than the respective conse...

No abstract is available for this article.

The preferences for localized chemicals production and changing scenarios of renewable electricity cost gives a renewed boost to plasma-assisted valuable chemicals production. Especially, plasma-assisted nitrogen fixation for fertilizer production has the potential to largely change the energy structure in bulk chemicals production. Nitrogen is the...

We report a visible light-induced trifluoromethylation and perfluoroalkylation for cysteine conjugation using Ru(bpy)32+ as photocatalyst and inexpensive RFI as coupling partner. The protocol allows the introduction of a variety of perfluoro alkyl groups (C1-C10) and of a CF2COOEt moiety. The reaction is high yielding (56-94% yield) and fast (2 hou...

Highly dispersed and size controlled Ni nanoparticles (NPs) in SBA-15 was synthesized by thermolysis of sucrose as a new delivery conveyor and sacrificial template. The Ni/SBA-15 catalysts were characterized systematically to elucidate their morphological structure and surface properties. It was found that the sucrose contributes majorly to control...

The direct synthesis of NOx from N2 and O2 by non-thermal plasma at an atmospheric pressure and low temperature is presented, which is considered to be an attractive option for replacement of the Haber-Bosch process. In this study, the direct synthesis of NOx was studied by packing different catalyst support materials in a dielectric barrier discha...

Herein, the first continuous cross-dehydrogenative homo-coupling of an unactivated arene using oxygen as sole oxidant is reported. Employing microreactor technology which enables the use of elevated temperatures and pressures leads to a boost of the catalytic reaction. Hence, a major reduction in reaction time is achieved. Due to the significance a...

Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given...

The direct synthesis of adipic acid from hydrogen peroxide and cyclohexene was investigated in capillary microreactors at high temperature (up to 115°C ) and pressure (up to 70 bar). High temperature was already applied in micro-flow packed-bed reactors for the direct adipic acid synthesis. In our previous work we showed that the process suffered f...

Chlorides represent a class of valuable intermediates that are utilized in the preparation of bulk and fine chemicals. An earlier milestone to convert bulk alcohols to corresponding chlorides was reached when hydrochloric acid was used instead of toxic and wasteful chlorinating agents. This paper presents the development of an intensified solvent-f...

Visible-light photocatalysis is a mild activation method for small molecules and enables a wide variety of transformations relevant for organic synthetic chemistry. However, one of the limitations of photocatalysis and photochemistry in general is the limited scalability due to the absorption of light (Lambert–Beer law). Here, we report the develop...

Nitrogen fixed in the form of nitrogen oxides is essential to produce fertilizers and many other chemical products, which is vital to sustain life. The performance of a milli-scale gliding arc reactor operated under atmospheric pressure has been studied for nitrogen oxides synthesis. In this work, the electrical and process parameters of the glidin...

This article features a historic industrial development concerning chemical synthesis of nitric acid from nitrogen, the Birkeland-Eyde process, which was started up in 1903. The whole development was done at great technological risk and also at the financial risk of having not enough backup by investors. It is a truly systemic development which nee...

Cinnarizine, cyclizine, buclizine, and meclizine belong to a family of antihistamines that resemble each other in terms of a 1-diphenylmethylpiperazine moiety. We present the development of a four-step continuous process to generate the final antihistamines from bulk alcohols as the starting compounds. HCl is used to synthesize the intermediate chl...

The two-step synthesis of phenol to 2-allylphenol in micro flow is investigated. This synthesis involves a nucleophilic substitution (SN2) reaction of phenol with allyl bromide towards allyl phenyl ether and the thermal Claisen rearrangement of allyl phenyl ether to 2-allylphenol. This carbon–carbon bond forming reaction route would provide a valua...

Process intensification via miniaturization has become an attractive research field for industry and R&D especially for the production of fine chemicals and pharmaceuticals due to enhanced mass and heat transport. Fabrication of helically coiled tubular devices (HCTDs) in micro-scale can further enhance the mass and heat transfer due to the formati...

Flow chemistry is typically used to enable challenging reactions which are difficult to carry out in conventional batch equipment. Consequently, the use of continuous-flow reactors for applications in organometallic and organic chemistry has witnessed a spectacular increase in interest from the chemistry community in the last decade. However, flow...

† Authors contributed equally to this work. In this protocol, we describe the construction and use of an operationally simple photochemical micro reactor for gas-liquid photoredox catalysis using visible light. The general procedure includes details on how to set up the microreactor appropriately with inlets for gaseous reagents and organic starti...

Rufinamide is an antiepileptic drug to treat Lennox–Gastaut syndrome, in combination with other medications. Rufinamide is one of the best-selling 5-membered ring heterocyclic pharmaceuticals. Its 1,2,3-triazole moiety is made by click chemistry-based cycloaddition of a dipolarophile and azide. We have recently shown the feasibility of a continuous...

Process-design intensification situated under the umbrella of Novel Process Windows heads for process integration and here most development is needed for flow separators. The vision is to achieve multi-step synthesis in flow on pilot scale. This calls for scale-up of separation units. This study is rare and thus conducted here. The coiled flow inve...

The photocatalytic aerobic oxidation of thiols to disulfides was investigated in a photomicroreactor. The importance of the base in this protocol is convincingly shown as it allows to activate the photocatalyst and to facilitate a proton coupled electron transfer. Based on these observations, a mechanism was postulated for the photocatalytic aerobi...

Continuous-flow liquid phase oxidation chemistry in microreactors receives a lot of attention as the reactor provides enhanced heat and mass transfer characteristics, safe use of hazardous oxidants, high interfacial areas, and scale-up potential. In this review, an up-to-date overview of both technological and chemical aspects of liquid phase oxida...

Increasing usage of catalytic chemistry calls for efficient removal of metal traces. This paper describes the development and optimization of a scavenger-based extraction in flow to remove metal catalysts. It enables liquid-liquid extraction with slug flow and phase separation with a porous fluoropolymer membrane. The use of this unit for copper sc...

Nitrogen is the most basic element responsible for the growth of living creatures on earth. Chemical nitrogen fixation process is one of the most important chemical processes, which sustains the growing global population. Wherein the life changing Haber-Bosch process comes into the picture, which produces more than 130 million tons of ammonia per y...

Life cycle assessment (LCA) and life cycle cost analysis are two prime tools that have been used to evaluate the sustainability of novel EU projects, which investigated new strategies to improve product yields and reduce costs, while ensuring a good ecological footprint and cost efficiency. These include EU projects focussed on developing modular,...

A compact photomicroreactor assembly consisting of a capillary microreactor and small-scale LEDs was developed for the study of reaction kinetics in the gas-liquid photocatalytic oxidation of thiophenol to phenyl disulfide within Taylor flow. The importance of photons was convincingly shown by a suction phenomenon due to the fast consumption of oxy...

Flow chemistry meanwhile has become almost regular branch of (synthetic) chemistry. Catalytic microreactors have also caught some attention; most prominently for small auxiliary power units driven by fuel processing. Under this umbrella, a kind of flow catalysis has emerged. Point is now is this "just" catalysis in flow or does the term justify - l...

Catalytic processes are of paramount importance in the chemical industry. Homogeneous catalysts are of great interest for synthesizing fine-chemical/specialty chemical/pharmaceutical products for their advantages of high activity and selectivity. However, their separation from the product remains a challenge. Transition metals and especially platin...

The environmental profile of plasma assisted methane reforming for the production of synthesis gas was researched. A miniaturized gliding arc discharge reactor was applied for the partial oxidation of methane in this study. The best operational condition regarding to the lowest CO2-eq emission was screened out. Studied were the global warming poten...

Heterogeneous catalysis, flow chemistry, continuous processing, green solvents, catalyst immobilization and recycling are some of the most relevant, emerging key technologies to achieve green synthesis. However, a quantification of potential effects on a case to case level is required to provide a profound answer, whether they can lead to a superio...

Disulfides represent significant molecular and structural features in various biologically active compounds and fine chemicals. Therefore, the development of mild, efficient and sustainable methods to access disulfides is of great importance. Here, we describe the development of a mild metal‐free photocatalytic aerobic oxidation of thiols to disulf...

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Microreactor technology has attracted a great deal of attention owing to the high control over the reaction parameters and the potential to use harsh reaction conditions. This chapter presents an overview of the advantages of microreactor technology for cross-coupling chemistry. The advantages and disadvantages of different catalyst sources that ca...

The methoxycarbonylation of cyclohexene with carbon dioxide over a ruthenium catalyst was realized in a micro flow system under supercritical conditions. Instead of the toxic and flammable carbon monoxide, this process utilizes carbon dioxide, thereby avoiding issues with bulk transportation of carbon monoxide as well as eliminating the need for sa...

Pressure effects on regioselectivity and yield of cycloaddition reactions have been shown to exist. Nevertheless, high pressure synthetic applications with subsequent benefits in the production of natural products are limited by the general availability of the equipment. In addition, the virtues and limitations of microflow equipment under standard...

In Part 2, the factors impacting the Claisen rearrangement both in batch and flow processing are analyzed, including the choice of substituent, catalyst, temperature, pressure, concentration, flow rates, and solvent. Part 1 of this review series discussed the potential of using short-time spectroscopy and quantum mechanical calculations to elucidat...

As the demand for new drugs is rising, the pharmaceutical industry faces the quest of shortening development time, and thus, reducing the time to market. Environmental aspects typically still play a minor role within the early phase of process development. Nevertheless, it is highly promising to rethink, redesign, and optimize process strategies as...

Die Claisen-Umlagerung wurde in über 100 Jahren durch zahlreiche Forscher äußerst eingehend im Rührbetrieb untersucht. Insbesondere der Reaktionsmechanismus wurde in allen Details erforscht. Quantenmechanische Modellierung und moderne Kurzzeit-Spektroskopie haben hier ganz neue Impulse gegeben. Auch wurden schon erste Erfahrungen im Durchflussbetri...

A new scale-up concept for microwave assisted flow processing is presented where modular scale-up is achieved by implementing microwave cavities in series. The scale-up concept is demonstrated for case studies of a packed-bed reactor and a wall-coated tubular reactor. With known kinetics and reaction temperature, a packed-bed reactor gave a convers...

This article describes the results of a modeling study performed to understand the microwave heating process in continuous-flow reactors. It demonstrates the influence of liquid velocity profiles on temperature and microwave energy dissipation in a microwave integrated milli reactor-heat exchanger. Horizontal co-current flow of a strong microwave a...

Herein, we report the first site-selective, Pd(II)-catalyzed, cross-dehydrogenative Heck reaction of indoles in micro flow. By use of a capillary microreactor, we were able to boost the intrinsic kinetics to accelerate former hour-scale reaction conditions in batch to the minute range in flow. The synergistic use of microreactor technology and oxyg...

The Claisen rearrangement is an ideal candidate for mechanistic and transition-state analysis. Recently, physical-chemistry investigations, in particular relying on quantum mechanics and modern fs-pulse (‘short-time') laser spectroscopy, have given totally new insights here. At the same time, flow chemistry has emerged, offering considerable proces...

A feasibility study in state‐of‐the‐art multi‐ and monomode microwave cavities was conducted to outline important functionalities necessary in a microwave setup for continuous fine‐chemicals synthesis. For multimode operation, the heating efficiency depends on the position as well as on the volume distribution of the load. For monomode operation, t...

The synthesis of 1,4-dihydropyridines was performed in a continuous-flow microreactor. Elevated temperatures accelerated the reaction rate significantly allowing the reaction to be finished in minutes (6-11 min). Different 1,4-dihydropyridines were prepared in good to excellent isolated yields (45-88% yield). The method was amenable to the preparat...

This review discusses the retention of organometallic catalysts in continuous flow processes utilizing supercritical carbon dioxide. Due to its innovative properties, supercritical carbon dioxide offers interesting possibilities for process intensification. As a result of safety and cost considerations, processes that use supercritical carbon dioxi...

In a time of increasing concerns about the immense energy consumption and poor environmental performance of contemporary processes in the chemical industry, there is great need to develop novel sustainable technologies that enhance energy efficiency. There is abundant chemical literature on process innovations (laboratory-scale) around the plasma r...

The synthesis of adipic acid from cyclohexene and hydrogen peroxide was investigated in micro-flow packed-bed reactors. The isolated yield of adipic acid increases with increasing residence time in micro-flow packed-bed reactors. The addition of phosphoric acid cannot effectively improve the isolated yield of adipic acid though it is generally know...

S–CF3 bonds are important structural motifs in various pharmaceutical and agrochemical compounds. However, their preparation remains a major challenge in synthetic organic chemistry. Here, we report the development of a mild and fast photocatalytic trifluoromethylation of thiols. The combination of commercially available Ru(bpy)3Cl2, visible light...

Continuous-flow photochemistry is used increasingly by researchers in academia and industry to facilitate photochemical processes and their subsequent scale-up. However, without detailed knowledge concerning the engineering aspects of photochemistry, it can be quite challenging to develop a suitable photochemical microreactor for a given reaction....

The current paper focuses on the miniaturization and utilization of the GlidArc® principle for the reforming of fuel gases (such as methane and propane) to synthesis gas (H2 + CO). The reforming characteristics and optimal operating conditions to achieve maximum synthesis gas yield were determined. Parametric screening studies were performed with d...

Various catalysts based on rhodium, palladium and platinum on γ-alumina were wash-coated into micro structured reactors. The catalysts were applied in the partial oxidation of propane aiming for synthesis gas. Best results were achieved with pure rhodium and bimetallic rhodium/platinum catalysts having at least a rhodium concentration exceeding 0.5...

Contenido: 1) Estado del arte de la tecnología de micro-reacción; 2) Técnicas modernas de micro fabricación de microreactores; 3) Micro-mezcladores; 4) Micro-cambiadores de calor; 5) Sistemas de micro-separación y módulos analíticos específicos para los microreactores; 6) Microsistemas para las reacciones en fase líquida; 7) Microsistemas para las...

Trifluoromethylated and perfluoroalkylated heterocycles are important building blocks for the synthesis of numerous pharmaceutical products, agrochemicals and are widely applied in material sciences. To date, trifluoromethylated and perfluoroalkylated hetero-aromatic systems can be prepared utilizing visible light photoredox catalysis methodologies...

EDGE denotes "Explain, Demonstrate, Guide, Enable" and comes from a concept for youth leadership development training. Biotechnical and enzymatic micro-flow reactors are a young discipline. Here the enthusiasm level mirrors its technological growth and vice versa. Rather than being a linear function, enthusiasm first goes down after sudden realizat...

A design methodology is proposed to maintain gas and liquid flow non-uniformities below an acceptable limit in a parallel micro/milli channels reactor by determining the maximum allowed temperature deviation in each part of the reactor. The effect of temperature deviation on flow distribution was quantified using a hydraulic resistive network model...

This article presents results on cost and performance benefit analysis of optimization and intensification activities of a pharmaceutical process. A batch process for the production of a low-volume, high value active pharmaceutical ingredient, developed at Sanofi (France), has been used as a case study. With the scale of 100 kg/y and a product pric...

A visible light photocatalytic metal-free perfluoroalkylation method for the functionalization of heteroarenes in continuous flow was developed. Eosin Y was the most efficient photocatalyst with regard to substrate scope, reaction time and cost prize. Faster reaction times were observed in continuous flow compared to batch due to an improved irradi...

The article contains sections titled: 1.Introduction2.Liquid-Phase Reactions2.1.The Importance of Homogeneity—Fast Mixing on the Microscale2.2.Performing Hazardous Homogeneous Reactions on a Microscale2.3.High-Temperature Processing2.4High-Pressure Processing2.5.Solvent Effects3.Liquid–Solid Flow3.1.Synthesis of Micro- and Nanostructured Materials...

Innovative ways of providing novel sustainable solutions to reduce the emissions and consumption of exhaustible resources is called for. Production of liquid fuels from bioresources satisfies this call and it is aimed to be achieved with BIOGO project. Proposed process involves coupled reforming of biogas and bio oil followed by methanol production...

To ensure mass transfer in biphasic reactions a sufficient interface area is required. A comparative study using standard interdigital micromixers with heptane/water (SDS) was described to evaluate on the performance of a special microreactor. These devices show a decrease of the average droplet size with energy, respectively flow rate, and flow co...

A parametric study of the factors that influence C–O bond formation reactions has been carried out to elucidate the mechanism by which copper mediates the Ullmann-type nucleophilic aromatic substitution (SNAr) of 4-chloropyridine with potassium phenolate. Process conditions such as temperature, reactant concentrations, catalyst concentration, and a...