Shishanov M.V.

Candidate of Chemical Sciences, Acting Head of the Department of Chemical Technology of Natural Energy Carriers and Carbon Materials, D.I. Mendeleev Russian University of Chemical Technology

Synthesis of 4,4’-methylenedianiline (MDA) in the microchannel

https://doi.org/10.58224/2619-0575-2024-7-3-34-48
Abstract
The work is devoted to the method of obtaining 4,4’-methylenedianiline (MDA) in a microchannel. MDA is produced on an industrial scale, mainly as a precursor to polyurethanes. This compound is also used as a hardener for epoxy resins, wire coatings, as well as in reinforced composite materials. The synthesis of MDA is accompanied by high temperature fluctuations, and the limiting factor is the rate of mass transfer. Microfluidics can solve these problems. The microreactors operate in a flow-through design in a laminar flow mode. Due to the small diffusion path of the molecules, the distribution of concentrations and temperatures is fast. This in turn increases the yield of the product, improves reaction control. It is also important in multiphase processes, where the mass transfer process takes place at the phase interface. It is microfluidics that allows precise control of the area of interfacial interaction, which is critical for these processes. However, during the synthesis of MDA, viscosity increases due to the formation of oligomers, which can clog the microchannel. A numerical simulation process was carried out, which revealed the projectile flow in the microchannel, which was also confirmed during the synthesis. A multifactorial experiment has been compiled, which is necessary to determine the optimal synthesis conditions. Parameters such as reaction temperature, component ratio, and residence time varied. The design of the experi-ment was used for successful synthesis. Based on the above parameters, two-dimensional and three-dimensional contour diagrams are constructed, representing mathematical models of the process under study. Due to their combination, the optimal technological parameters of the process were established.
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Optimization of the flow part of the microfluidic channel

https://doi.org/10.58224/2619-0575-2024-7-2-4-12
Abstract
In this paper, the features of microfluidic channel optimization are considered. The microfluidic channel is a key component of the microreactor, its shape and features of the hydrodynamic regime directly affect the successful course of chemical reactions carried out in it. The microfluidic industry regulates processes occurring in small volumes of liquids – on the order of a nano liter or less. It is applicable to various fields such as microelectronics, pharmaceuticals, specialty chemicals, etc. The Comsol Multiphysics computational modeling program was used as an optimization tool. It is based on the finite element method, which allows you to accurately model the problems of the hydrodynamic profile. In this article, the simplest form of a microchannel is considered – a 0.75 mm circular channel with a mixing cell. The mathematical modeling of the process is given, the optimality criterion adequate for the task is determined. As one of the components of this criterion, diodicity was used – a criterion that determines the ability to pass a stream in the forward direction, provided there is a reverse flow. As a result of this work, the most optimal shape of the microreactor channel satisfying the required process conditions was identified, the main hydrodynamic parameters were obtained and the dependence of the diode on the criterion used was determined.
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Optimization of a typical condensation process using the example of isophorone synthesis in a microchannel

https://doi.org/10.58224/2619-0575-2024-7-2-43-52
Abstract
The work is devoted to the method of obtaining isophorone in a microchannel. Numerical and experimental optimization of the process of obtaining isophorone in a microchannel has been carried out. Isophorone is an unsaturated cyclic ketone, widely used in industry as a solvent for nitrocellulose paints, as well as as an inter-mediate for the synthesis of other compounds. The synthesis was carried out in microchannels. Microchannels are channels with a diameter of less than 1 mm. Their main feature is the possibility of carrying out various types of reactions requiring high pressures and temperatures. Due to the small internal volume, all processes occurring in them are easily intensified, high accuracy and efficiency of the experiment can be achieved. Parameters such as reaction temperature and reagent consumption varied. A new approach to conducting the experiment was used, based on minimizing the control parameters used and combining them correctly. This approach requires high ac-curacy and reproducibility of the results, so the microchannels used in this work are the best choice for such tasks. A mathematical model of the reaction based on systems of equations of varying complexity has been developed. Three-dimensional and two-dimensional contour diagrams are constructed to visualize the mathematical model of the process. The best technological parameters of the process have been established.
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