Search results for "Microreactor"

Electrochemical processes in macro and microfluidic cells for the abatement of chloroacetic acid from water

2014

Segmented Flow-Based Multistep Synthesis of Cadmium Selenide Quantum Dots with Narrow Particle Size Distribution

2015

A continuous-flow microreactor was used to synthetize II-VI semiconductor quantum dots (CdSe). In order to improve the size distribution of the nanoparticles, the synthesis was carried out in a two-step procedure. A seed solution was obtained in a separate nucleation step, followed by a controllable growth step. Quantum dots that are synthesized with the two-step method show a much narrower size distribution in comparison to those obtained in a conventional batch synthesis.

Decision support towards agile eco-design of microreaction processes by accompanying (simplified) life cycle assessment

2011

Continuously running syntheses in microstructured reactors offers novel ways to intensify conventional chemical processes. An outstanding advantage of microreaction technology is the high surface-to-volume-ratio which enables intensive mixing phenomena as well as high mass and heat transfer rates. Thus, microstructured reactors may be a suitable means to improve multiphase reactions by increasing the interfacial area and the intensification of internal mixing. This improvement in reaction performances may lead to reduced environmental burdens of the process under consideration. The method of simplified life cycle assessment (SLCA) is a suitable tool to evaluate the environmental burdens cau…

Organic Chemistry in Microreactors

2008

ELECTROCHEMICAL CONVERSION OF DICHLOROACETIC ACID TO CHLOROACETIC ACID IN A MICROFLUIDIC STACK AND IN A SERIES OF MICROFLUIDIC REACTORS

2015

The electrochemical conversion of dichloroacetic acid to chloracetic acid was performed in three different micro devices: a simple micro fluidic cell; a microfluidic stack equipped with various electrode chambers in series and three micro fluidic cells in series. The electrochemical synthesis of chloracetic acid was performed successfully with high yields and selectivity under a single-pass mode without supporting electrolyte at low cell voltages. An increase of the productivity and of the final concentration of the target product was achieved by using a stack with two or three electrode chambers in series. The utilization of three micro reactors in series open interesting new perspectives,…

Abatement of Acid Orange 7 in macro and micro reactors. Effect of the electrocatalytic route

2014

Abstract The electrochemical treatment of aqueous solutions contaminated by Acid Orange 7 (AO7) was widely studied with the main objective to evaluate as the electrocatalytic route affects the performances of the degradation process in macro and microfluidic cells. Direct anodic oxidation (EO), electro-Fenton (EF), electro-generation of active chlorine (IOAC) and coupled processes were investigated in macro and microfluidic reactors in order to select more effective conditions for the treatment of such compound. The effect of numerous operative parameters (such as nature of the electrode materials, coupling of processes, flow rate, current density and inter-electrode distance) on the perfor…

Addition of Secondary Amines to α,β-Unsaturated Carbonyl Compounds and Nitriles by Using Microstructured Reactors

2006

Several additions of amines to a,ß-unsaturated carbonyl compounds (Michael additions) were performed in a continuous-flow microstructured reactor rig and compared to the respective batch reaction. Dimethylamine/diethylamine/piperidine and acrylic acid ethyl ester/acrylonitrile were employed as two sets of reactants, giving six reactions. Some of these reactions are highly exothermal. Using the traditional batch procedure the olefin must be added quite slowly to the diluted amine to ensure temperature control and safe operation; especially this is necessary for the addition of dimethylamine (40 mass % aqueous solution) to acrylonitrile. Good yields (>85%) are achieved in this way; however…

Time-resolved X-ray powder diffraction on a three-way catalyst at the GILDA beamline

2003

Time-resolved X-ray diffraction experiments carried out at the beamline BM08-GILDA of ESRF allowed a study of the structural modifications taking place in a Pt/ceria-zirconia catalyst while the CO oxidation reaction was in progress. The capillary tube in which the sample is stored acts effectively as a chemical microreactor that ensures homogeneity of the sample treatments and minimization of diffusion effects. During the flowing of the reactant CO/He mixture, the investigated catalyst undergoes a fast Ce(IV)-Ce(III) partial reduction that involves the release of one O atom for every two reduced Ce cations. Because Ce(III) has a larger ionic radius than Ce(IV), the structural modification p…

DEVELOPMENT OF ELECTROCHEMICAL MICROFLUIC DEVICES FOR THE TREATMENT OF WASTEWATERS AND THE SYNTHESIS OF CHEMICAL

Reaction Condition Screening by Using Electrochemical Microreactor: Application to Anodic Phenol-arene C,C Cross-Coupling Reaction in High Acceptor N…

2013

The anodic phenol-arene C,C cross-coupling reaction was achieved in inexpensive and sustainable media such as methanol, acetic acid, and formic acid by using an electrochemical microreactor which can provide a better performance to screen reaction conditions than in standard beaker-type electrolysis cells. Especially, formic acid as a reaction medium showed good performance. The total amount of cross-coupling product and homo-coupling products as a by-product was clearly increased as the solvent acceptor number increased. To control the selective oxidation of phenol, addition of methanol was effective.