High‐yield production of p‐diethynylbenzene through consecutive bromination/dehydrobromination in a microreactor system

Abstract

Polyarylacetylene resins have received great attention due to their outstanding heat resistance, while the absence of an efficient method to produce their monomer, p-diethynylbenzene (p-DEB), has discouraged their commercial development. Industrial production of p-DEB consists of bromination and dehydrobromination in a semibatch reactor, state of the art yield from which is only 70%-75%. Herein, a combined effort of byproduct characterization and density functional theory calculations revealed that side reactions mainly consisted of aromatic substitution which would be promoted by thermal runaway derived from exothermic bromination due to higher activation energy of side reactions. From these considerations, we developed a microreactor system to enhance heat transfer thereby mitigating byproduct formation, from which a p-DEB yield of 99.2% could be achieved. Moreover, the high heat removal efficiency avoided the use of slow feeding and reactant dilution required in semi-batch operation, thereby shortening the reaction time to 14 s while generating more concentrated product.

Kinetically guided high‐yield and rapid production of ε‐caprolactone in a microreactor system

“…Microreactors were then used to mitigate the “thermal runaway” and a temperature rise <7.7°C was obtained at equivalent reaction conditions as batch operation when the characteristic size of the reactor decreased to 1.2 mm. The heat removal capacity of the microreactor was estimated using heat transfer calculations 42 . The microreactor was then used for kinetic studies of BV oxidation of CYC and the results were shown in Figure 2.…”

“…The heat removal capacity of the microreactor was estimated using heat transfer calculations. 42 The microreactor was then used for kinetic studies of BV oxidation of CYC and the results were shown in Figure 2. The initial reaction rates were approximately acquired using average reaction rates given the nearly linear relationship between CYC consumption and reaction time at conversions <15% (Figure 2A,C).…”

Homogeneous, heterogeneous, and enzyme catalysis in microfluidics droplets

“…Microdroplets are widely used as microreactors in a variety of applications, such as biochemical reactions, rapid mixing, and microparticle synthesis. [1][2][3] Microfluidic platforms have shifted the paradigm of biochemical experimentation over the past 3 decades. [4,5] A key component of this technology is the droplet-based microfluidic system, which utilizes passive microfluidic structures to quickly produce and control subnanometer-sized droplets in microchannel environments.…”

“…Microdroplets are widely used as microreactors in a variety of applications, such as biochemical reactions, rapid mixing, and microparticle synthesis [1–3] . Microfluidic platforms have shifted the paradigm of biochemical experimentation over the past 3 decades [4,5] .…”