The simple transfer of established chemical production processes from batch to flow chemistry does not automatically result in more sustainable ones. Detailed process understanding and the motivation to scrutinize known process conditions are necessary factors for success. Although the focus is usually "only" on intensifying transport phenomena to operate under intrinsic kinetics, there is also a large intensification potential in chemistry under harsh conditions and in the specific design of flow processes. Such an understanding and proposed processes are required at an early stage of process design because decisions on the best-suited tools and parameters required to convert green engineering concepts into practice-typically with little chance of substantial changes later-are made during this period. Herein, we present a holistic and interdisciplinary process design approach that combines the concept of novel process windows with process modeling, simulation, and simplified cost and lifecycle assessment for the deliberate development of a cost-competitive and environmentally sustainable alternative to an existing production process for epoxidized soybean oil.
The soybean oil epoxidation reaction is investigated theoretically through kinetic modeling of temperature effects enabled through flow processing under superheated conditions. Different from previous studies on such processing, here a complex reaction network superimposed by multiphase transport is considered; with one elemental step-the hydrogen peroxide decomposition-which can defeat the much boosted product formation. For such a delicate reaction network, the accessibility of accurate and reliable kinetics is absolutely essential, especially when exploring this completely new temperature range. Initially, an overview of the actual kinetic models is given, this gives rise to implications for the study developed here considering high temperature flow processing, heat removal efficiency, hotspot formation, and the effect of different hydrogen peroxide decomposition kinetics. Subsequently an optimized process involving the use of microreactors at different temperatures is proposed for the process management of the reaction heat and to yield a commercial grade product under notably intensified conditions. The results are then benchmarked with quantitative, challenging process improvement criteria set by an industrial partner.
This paper explains the reasons behind the very low polydispersity index (PDI) obtained in living anionic polymerizations in microstructured reactors. From the results, it can be explained that a narrow molecular weight distribution can be obtained due to the presence of a highly segregated flow behavior, even in microflow conditions, provided that the mean residence time is high enough. This paper investigates the feasibility of a living anionic polymerization reaction under micro‐fluidic conditions. This is accomplished using a multiphysics model that accounts for the changes in viscosity and diffusivity. These properties descend with the increase in weight of the polymer, and could not be un‐coupled from hydrodynamics and mass transfer. The results of the model are used to understand the reasons behind the very low PDI that can be experimentally obtained in microflow conditions. This leads to the conclusion that the increased viscosity almost “suppresses” the diffusion of the monomer, even at the very short characteristic lengths of a micro‐device. These conditions generate a fully segregated flow that yields an almost monodisperse polymer regardless of the effective residence time distribution encountered in the reactor. magnified image
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