The fine chemicals and pharmaceutical industries are transforming how their products are manufactured, where economically favorable, from traditional batchwise processes to continuous flow. This evolution is impacting synthetic chemistry on all scales-from the laboratory to full production. This Review discusses the relative merits of batch and micro flow reactors for performing synthetic chemistry in the laboratory.

Deciding whether to go with the flow: evaluating the merits of flow reactors for synthesis.

http://iglesia.cchem.berkeley.edu/Publications/JournalofCatalysis_224_370_2004.pdf

Isotopic and kinetic assessment of the mechanism of reactions of CH4 with CO2 or H2O to form synthesis gas and carbon on nickel catalysts

Hydrodynamics and mass transfer characteristics in gas–liquid flow through a rectangular microchannel

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 oxidation chemistry in continuous-flow microreactors is given. A description of mass and heat transfer phenomena is provided and fundamental principles are deduced which can be used to make a judicious choice for a suitable reactor. In addition, the safety aspects of continuous-flow technology are discussed. Next, oxidation chemistry in flow is discussed, including the use of oxygen, hydrogen peroxide, ozone and other oxidants in flow. Finally, the scale-up potential for continuous-flow reactors is described.

/pdf/liquid-phase-oxidation-chemistry-in-continuous-flow-q8s21u2ge1.pdf

Liquid phase oxidation chemistry in continuous-flow microreactors

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. In this review, we provide an up-to-date overview of both technological and chemical aspects associated with photochemical processes in microreactors. Important design considerations, such as light sources, material selection, and solvent constraints are discussed. In addition, a detailed description of photon and mass-transfer phenomena in microreactors is made and fundamental principles are deduced for making a judicious choice for a suitable photomicroreactor. The advantages of microreactor technology for photochemistry are described for UV and visible-light driven photochemical processes and are compared with their batch counterparts. In addition, different scale-up strategies and limitations of continuous-flow microreactors are discussed.

Photochemical transformations accelerated in continuous-flow reactors : basic concepts and applications

Catalytic combustion assisted methane steam reforming in a catalytic plate reactor

Carbon dioxide absorption in sodium hydroxide solution was performed in a microstructured falling film gas−liquid reactor. The liquid phase was distributed on a reaction plate of 64 microchannels of 300 × 100 μm having a length of 66.4 mm, while the gas-phase was guided in a gas chamber with a depth of 5.5 mm or 2.5 mm. Experimental data were obtained keeping a fixed overall liquid flowrate of 50 mL/h, using three different NaOH inlet concentration (0.1, 1, and 2 M) and a fixed inlet molar ratio CO2:NaOH of 0.4, for a range of CO2 concentration of 0.8−100%. A plate with 16 microchannels of 1200 μm × 400 μm was also employed. A two-dimensional model was formulated to simulate the reactor, and experimental results were compared to model prediction in terms of carbon dioxide conversion. The model gives good agreement with the experimental data at low inlet NaOH concentration (0.1 and 1 M), while the agreement with the experiments at 2 M NaOH is reasonable only for low CO2 inlet concentration. The model indic...

Carbon dioxide absorption in a falling film microstructured reactor : Experiments and modeling

Modelling of a catalytic plate reactor for dehydrogenation–combustion coupling

A theoretical study of the influence of flow arrangement on the thermal behaviour of a catalytic plate reactor (CPR) for steam reforming of methane using methane catalytic combustion as heat source based on a two-dimensional model is presented. CPR performance and thermal behaviour is strongly affected by overall and local balance between heat generated on the exothermic side and heat consumed on the endothermic one, which in turn is influenced by flow arrangement. Simulations for co-current and counter-current flow were carried out for similar inlet conditions and catalyst loadings. It was found that the reactor is better balanced thermally for co-current operation. For counter-current arrangement, higher conversions and better utilization of the overall heat generated in the exothermic process are achieved at the expense of pronounced temperature extremes. Thus, reforming conversion for counter-current operation is 62.8% compared with 52% for co-current operation, whilst maximum transverse temperature difference for co-current operation is only 16.5K compared with 310K for counter-current operation. This increases the chances of the reactor running away and of homogeneous combustion being initiated. Utilization of a non-uniform catalyst distribution can overcome the heat imbalance by inducing favourable reactant depletion along the reactor during counter-current flow.

M. Zanfir

Papers

Catalytic combustion assisted methane steam reforming in a catalytic plate reactor

Carbon dioxide absorption in a falling film microstructured reactor : Experiments and modeling

Modelling of a catalytic plate reactor for dehydrogenation–combustion coupling

Influence of Flow Arrangement in Catalytic Plate Reactors for Methane Steam Reforming

Scalable Reactor Design for Pharmaceuticals and Fine Chemicals Production. 1: Potential Scale-up Obstacles