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The multistep and continuous production of core–shell III–V semiconductor nanocrystals remains a technological challenge. We present a newly designed high-temperature and miniature continuous stirred-tank reactor cascade, for the continuous and scalable synthesis of InP/ZnS core–shell quantum dots with a safer aminophosphine precursor comparing to standard protocols involving (TMS)3P. The resulting InP/ZnS QDs exhibit emissions between 520 and 610 nm, narrow emission linewidths in the range of 46–64 nm and photoluminescence quantum yields up to 42%.

Electroorganic synthesis is a promising tool to design sustainable transformations and discover new reactivities. However, the added setup complexity caused by electrodes in the system impedes efficient screening of reaction conditions. Herein, we present a microfluidic platform that enables automated high-throughput experimentation (HTE) for electroorganic synthesis at a 15-microliter scale. Two HTE modules are demonstrated: 1) the rapid electrochemical reaction condition screening for a radical-radical cross-coupling reaction on micro-fabricated interdigitated electrodes, and 2) measurements of kinetics for mediated anodic oxidations using the microliter-scale cyclic voltammetry. The presented modular approach could be deployed for a range of other electroorganic chemistry applications beyond the demonstrated functionalities.

Visible-light photoredox reactions have been demonstrated to be powerful synthetic tools to access pharmaceutically relevant compounds. However, many photoredox reactions involve insoluble starting...

For many carbon–carbon and carbon–nitrogen bond-forming reactions, the stoichiometric formation of inorganic salt crystals limits continuous flow synthesis by causing precipitation, agglomeration, ...

Electroorganic chemistry has emerged as an environmentally benign tool for synthetic chemists to achieve efficient transformations that are challenging with traditional reagent-based methods. Continuous flow chemistry brings pharmaceutical industry numerous advantages, but implementing electroorganic synthesis in flow is challenging, especially for electroorganic reactions with coupled electrode reactions and slow chemical reactions. We present a continuous electrolysis system engineered for N-hydroxyphthalimide (NHPI) mediated electrochemical aerobic oxidation of benzylic C-H bonds. First, a cation-exchange membrane prevents the crossover of the NHPI anion from anolyte to catholyte avoiding reductive decomposition of NHPI at the cathode, and enables the usage of a cost-effective reticulated vitreous carbon (RVC) cathode instead of a platinum electrode. Second, running the electrochemical flow cell with recycle streams accommodates the inherently slow kinetics of the chemical reaction without phthalimide-N-oxyl (PINO) radical self-decomposition at the anode, and allows the usage of gaseous oxygen as co-oxidant.

Chemical transformations used in fine chemical manufacturing often involve two-phase interaction for which mass transfer limitations can lead to prolonged reaction time and reduced productivity. We present a high-performance miniature continuous stirred-tank reactor (CSTR), with non-contact magnetic coupling providing intensive agitation inside the sealed miniaturized chamber. High-speed imaging of the biphasic hydrodynamics gives an estimated mass transfer coefficient (kLa) on the order of 10 s−1, comparable to commercial passive mixing flow reactors. Case studies with two important biphasic C–C bond-forming reactions: (i) asymmetric alkylation catalyzed by cinchonidine-derived phase-transfer catalyst, and (ii) biphasic Suzuki-Miyaura C–C coupling reactions, demonstrate the versatility of the CSTR unit. Moreover, a detailed kinetic model proposed for phase-transfer reaction systems controlled by the Makosza interfacial mechanism further cross-validates the mass transfer coefficient estimates.

Catalytic gas–liquid reactions have potential as environmentally benign methods for organic synthesis, particularly hydrogenation and oxidation reactions. However, safety and scalability are concerns in the application of gas–liquid reactions. In this work, we develop and demonstrate a scalable, sustainable, and safe thin-layer membrane reactor for heterogeneous Pd-catalyzed hydrogenations and homogenous Cu(I)/TEMPO alcohol oxidations. The implementation of a Teflon amorphous fluoroplastic (AF) membrane and porous carbon cloth in the membrane reactor provides sufficient gas–liquid mass transfer to afford superior performance compared to conventional packed-bed or trickle-bed reactors. The membrane separates the gas from the liquid, which avoids the formation of explosive mixtures for oxygenation reactions and simplifies the two-phase hydrodynamics to facilitate scale-up by stacking modules, while significantly reducing gas consumption. In addition, 3-dimensional simulations deliver insights into the mass transfer and hydrodynamic behavior to inform optimal membrane reactor design and operation.

Continuous handling of solids creates challenges for realizing continuous production of pharmaceuticals and fine chemicals. We present a new miniature continuous stirred-tank reactor (CSTR) cascade to handle solid-forming reactions in flow. Single-phase residence time distribution (RTD) measurements of the CSTR cascade reveal nearly ideal CSTR mixing behavior of the individual units. Consistency of experimental and predicted conversions of a Diels–Alder reaction further confirms the CSTR performance. Two solid-forming reactions, (i) glyoxal reacting with cyclohexylamine to form N,N′-dicyclohexylethylenediimine, (ii) sulfonylation of 2-octanol with methanesulfonyl chloride, demonstrate the ability of the reactor cascade to transport solid particles continuously for hours without significant signs of clogging.