Flow Chemistry in Contemporary Chemical Sciences: A Real Variety of Its Applications

Abstract

Flow chemistry is an area of contemporary chemistry exploiting the hydrodynamic conditions of flowing liquids to provide particular environments for chemical reactions. These particular conditions of enhanced and strictly regulated transport of reagents, improved interface contacts, intensification of heat transfer, and safe operation with hazardous chemicals can be utilized in chemical synthesis, both for mechanization and automation of analytical procedures, and for the investigation of the kinetics of ultrafast reactions. Such methods are developed for more than half a century. In the field of chemical synthesis, they are used mostly in pharmaceutical chemistry for efficient syntheses of small amounts of active substances. In analytical chemistry, flow measuring systems are designed for environmental applications and industrial monitoring, as well as medical and pharmaceutical analysis, providing essential enhancement of the yield of analyses and precision of analytical determinations. The main concept of this review is to show the overlapping of development trends in the design of instrumentation and various ways of the utilization of specificity of chemical operations under flow conditions, especially for synthetic and analytical purposes, with a simultaneous presentation of the still rather limited correspondence between these two main areas of flow chemistry.

Flow-Through PolyHIPE Silver-Based Catalytic Reactor

“…Furthermore, due to its open structure, the predominant transport mechanism is convection, minimizing diffusional limitations to active sites [ 8 , 24 , 25 ]. Due to negligible mass transport resistance, they enable studies of catalytic reaction kinetics at constant or variable conditions, providing new insights into the reaction mechanism [ 26 ]. Attachment of silver nanoparticles on their pore surface can be achieved through various functional groups such as amines [ 5 ], aldehydes [ 27 , 28 ], or chelating agents [ 12 ] that can act as nucleation sites and anchors for nanoparticles formed via established wet chemistry techniques [ 29 ].…”

Kinetic Modeling of Advanced Oxidation Processes Using Microreactors: Challenges and Opportunities for Scale-Up

“…The use of microreactors, with dimensions in the range of 10-1000 µm, represents a promising technology for the estimation of intrinsic parameters and mechanistic studies [22][23][24][25]. Among the advantages they offer are (i) faster degradation kinetics, resulting in time-efficient experimental campaigns-this also allows to use cheap low-voltage lamps or light-emitting diodes (LEDs) systems [26] more efficiently when photocatalytic systems are investigated; (ii) reduced size-in addition to compactness and intrinsic safety, these devices present lower spatial gradients of the physical variables, e.g., light intensity and concentrations, resulting in simplified models and more precise parameter estimation [12]; (iii) reduced volumes with economic advantages in terms of amount of required materials and reduced amount of produced waste [23]; (iv) continuous flow operations, with the possibility of automation and direct coupling with analytical instruments; this allows to save additional time and resources by carrying out experiments in a fully automated fashion [27][28][29]; (v) adoption of very small amounts of immobilized solid catalysts and efficient gas-liquid and liquid-liquid mass transfer, depending on the investigated system [12,22].…”

Development of a Simple Reversible-Flow Method for Preparation of Micron-Size Chitosan-Cu(II) Catalyst Particles and Their Testing of Activity

“…Thus, this work aims to produce uniform micron-size CS-Cu(II) catalyst particles with narrow size distribution employing a simple flow method. It is efficient to produce the uniform with consistent size of synthesized catalyst due to the designs of flow instruments are promising with various platforms for flow synthesis [24]. Chitosan is employed as the substrate for synthesizing the heterogeneous metal catalysts.…”