Atom Transfer Radical Polymerization in Continuous Microflow Effect of Process Parameters
28 Apr 2014-Journal of Flow Chemistry (Akadémiai Kiadó, co-published with Springer Science+Business Media B.V., Formerly Kluwer Academic Publishers B.V.)-Vol. 4, Iss: 2, pp 92-96
TL;DR: In this paper, the synthesis of 2-(dimethylamino)ethyl methacrylate by atom transfer radical polymerization (ATRP) in tubular microreactors was reported.
Abstract: We report on the synthesis of 2-(dimethylamino)ethyl methacrylate by atom transfer radical polymerization (ATRP) in tubular microreactors. Different process parameters, temperature, pressure, and shear rate, were considered to accelerate the reaction. Increase in temperature induced a faster reaction, but controlled nature of ATRP decreased past a threshold value that can be increased up to 95 °C by reducing the residence time. Positive effect of pressure was observed since significant increases in monomer conversion (+12.5 %) and molecular weight (+5,000 g/mol) were obtained. Moreover, polydispersity index was found to decrease from 1.52 at normal pressure to 1.44 at 100 bars. Benefit of pressure was more visible in smaller reaction space (smaller tube diameter). Finally, shear rate has quite an influence on the early stage of the polymerization and is expressed by an increase in the reaction rate. However, the effect was dimed for long residence times.
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TL;DR: The adaptation of O-ATRP to a continuous flow approach has been performed with multiple visible-light absorbing photoredox catalysts and improved polymerization results were achieved, revealing continuous flow O-atRP to be a robust and versatile method of polymerization.
Abstract: Organocatalyzed atom transfer radical polymerization (O-ATRP) has emerged as a metal-free variant of historically transition-metal reliant atom transfer radical polymerization. Strongly reducing organic photoredox catalysts have proven capable of mediating O-ATRP. To date, operation of photoinduced O-ATRP has been demonstrated in batch reactions. However, continuous flow approaches can provide efficient irradiation reaction conditions and thus enable increased polymerization performance. Herein, the adaptation of O-ATRP to a continuous flow approach has been performed with multiple visible-light absorbing photoredox catalysts. Using continuous flow conditions, improved polymerization results were achieved, consisting of narrow molecular weight distributions as low as 1.05 and quantitative initiator efficiencies. This system demonstrated success with 0.01% photocatalyst loadings and a diverse methacrylate monomer scope. Additionally, successful chain-extension polymerizations using 0.01 mol % photocatalyst...
104 citations
TL;DR: In this paper, a comprehensive overview of polymer reactions being carried out in continuous flow reactors is presented, concluding with the most recent examples on automated polymer synthesis, reactor telescoping and nanoparticle synthesis.
72 citations
TL;DR: The utility and promise of photo-CRP approaches are highlighted through an overview of the adaptation of these methodologies to photo-flow reactor systems, with special emphasis on the current state-of-the-art in polymerization scalability, reactor design, and polymer scope.
Abstract: Photoinduced controlled radical polymerizations (CRPs) have provided a variety of approaches for the synthesis of polymers possessing targeted structures, compositions, and functionalities with the added capability for spatial and temporal control, presenting the potential for new materials development. However, the scalability and reliability of these systems can be limited as a consequence of dependence on uniform irradiation of the reaction to produce well-defined products. In this perspective, we highlight the utility and promise of photo-CRP approaches through an overview of the adaptation of these methodologies to photo-flow reactor systems. Special emphasis is placed on the current state-of-the-art in polymerization scalability, reactor design, and polymer scope.
58 citations
32 citations
TL;DR: In this paper, the authors highlighted the recent new progress in continuous flow RDRP in the last five years and highlighted the utility of microflow technique to improve the polymerization process.
27 citations
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Book•
30 Jun 1972TL;DR: An overview of Chemical Reaction Engineering is presented, followed by an introduction to Reactor Design, and a discussion of the Dispersion Model.
Abstract: Partial table of contents: Overview of Chemical Reaction Engineering. HOMOGENEOUS REACTIONS IN IDEAL REACTORS. Introduction to Reactor Design. Design for Single Reactions. Design for Parallel Reactions. Potpourri of Multiple Reactions. NON IDEAL FLOW. Compartment Models. The Dispersion Model. The Tank--in--Series Model. REACTIONS CATALYZED BY SOLIDS. Solid Catalyzed Reactions. The Packed Bed Catalytic Reactor. Deactivating Catalysts. HETEROGENEOUS REACTIONS. Fluid--Fluid Reactions: Kinetics. Fluid--Particle Reactions: Design. BIOCHEMICAL REACTIONS. Enzyme Fermentation. Substrate Limiting Microbial Fermentation. Product Limiting Microbial Fermentation. Appendix. Index.
8,257 citations
TL;DR: In this paper, it was shown analytically that the distribution of concentration produced in this way is centred on a point which moves with the mean speed of flow and is symmetrical about it in spite of the asymmetry of the flow.
Abstract: When a soluble substance is introduced into a fluid flowing slowly through a small-bore tube it spreads out under the combined action of molecular diffusion and the variation of velocity over the cross-section. It is shown analytically that the distribution of concentration produced in this way is centred on a point which moves with the mean speed of flow and is symmetrical about it in spite of the asymmetry of the flow. The dispersion along the tube is governed by a virtual coefficient of diffusivity which can be calculated from observed distributions of concentration. Since the analysis relates the longitudinal diffusivity to the coefficient of molecular diffusion, observations of concentration along a tube provide a new method for measuring diffusion coefficients. The coefficient so obtained was found, with potassium permanganate, to agree with that measured in other ways. The results may be useful to physiologists who may wish to know how a soluble salt is dispersed in blood streams.
4,530 citations
TL;DR: In this article, a review of recent mechanistic developments in the field of controlled/living radical polymerization (CRP) is presented, with particular emphasis on structure-reactivity correlations and "rules" for catalyst selection in ATRP, for chain transfer agent selection in reversible addition-fragmentation chain transfer (RAFT) polymerization, and for the selection of an appropriate mediating agent in stable free radical polymerisation (SFRP), including organic and transition metal persistent radicals.
2,869 citations
TL;DR: Atom transfer radical polymerization (ATRP) has been successfully carried out in supercritical carbon dioxide (scCO2) for the polymerization of fluorinated (meth)acrylates as mentioned in this paper.
Abstract: Atom transfer radical polymerization (ATRP) has been successfully carried out in supercritical carbon dioxide (scCO2) for the polymerization of fluorinated (meth)acrylates. In particular, well-controlled polymerizations have been obtained with the use of a fluoroalkyl-substituted 2,2‘-bipyridine ligand. Block copolymers comprised of fluorinated (meth)acrylates and poly(MMA) (MMA = methyl methacrylate) or poly(DMAEMA) (DMAEMA = 2-(dimethylamino)ethyl methacrylate) were produced in scCO2 by ATRP. In addition, the dispersion polymerization of MMA using ATRP in scCO2 in the presence of a fluorinated polymeric surfactant stabilizer was successfully carried out to yield poly(MMA) latex particles with controlled molecular weight and a narrow molecular weight distribution.
198 citations
TL;DR: In this article, the thermal decomposition of a radical initiator, AIBN, in a micro-reactor was examined, and the plots of unchanged AIBN against the residence time fitted well to the calculated one based on the bath temperature, indicating the efficient heat transfer through the wall of the microreactor.
Abstract: The thermal decomposition of a radical initiator, AIBN in a microreactor was examined. The plots of unchanged AIBN against the residence time fitted well to the calculated one based on the bath temperature, indicating the efficient heat transfer through the wall of the microreactor by virtue of a high surface-to-volume ratio. The effectiveness of the microreactor on the molecular weight distribution control was then examined. For the polymerization of butyl acrylate (BA), the polydispersity index (PDI) of the polymer obtained using the microreactor was much smaller than that obtained with a macroscale batch reactor. The result can be explained in terms of much higher heat removal efficiency of the microreactor compared with the macroscale batch reactor. For the polymerization of benzyl methacrylate (BMA) and methyl methacrylate (MMA), the effect of the microreactor on PDI was smaller than in the case of BA. For the polymerization of vinyl benzoate (VBz) and styrene (St), no appreciable effect of microreac...
194 citations