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Organometallic reactions involving highly reactive organolithium reagents are widely used in organic synthesis. However, the use of such organometallics in batch mode on a pilot and industrial scale is challenging for safety reasons and frequently requires expensive cryogenic process conditions. A change to continuous processing in flow mode can provide major advantages for process safety and economics. In this study, we compare static and dynamic flow reactor technologies for two important organolithium (butyllithium and hexyllithium)-enabled transformations: deprotonations and bromine/lithium exchange reactions. Using higher concentrated (≥3 M) butyllithium (BuLi) solutions, that is, reaction mixtures with reduced hydrocarbon content, decreases the risk of reactor fouling and allows for increased space/time yields. In the flow mode, the observed reactions could be carried out under more convenient conditions, that is, at higher temperatures compared to the batch mode, and the deprotonation reaction even at ambient temperature instead of −78 °C. The formation of precipitates with the risk of clogging can be further reduced by changing from static flow to dynamic spinning disc reactor technology. The SpinPro reactor system from Flowid has been identified to ensure robust performance, as it tolerates salt precipitations and can provide excellent mass transfer conditions. Flow process technology using concentrated organolithium products can provide unique benefits for the manufacturing of pharmaceutical intermediates, agrochemical products, and specialty chemicals.

In Reaktionsgemischen von Acetylenen RC  CR (1) mit R  H, CH3, C2H5, C3H7, C4H9, C(CH3)3, C6H5 mit ClSSCl/AlCl3/H2CCl2 oder mit S8/SbCl5/H2CCl2 lassen sich bei 250 K zunächst 1,2‐Dithiet‐Radikalkationen R2C2S2⊕ (2a – g) und nach Erwärmen auf 300 K zusätzlich 1,4‐Dithiin‐Radikalkationen R4C4S2⊕ (3) ESR‐spektroskopisch nachweisen. Ihre Erzeugung gelingt auch durch Umsetzung von 1,2‐Dichlorethen‐ oder 1,1,2,2‐Tetrabrom‐ethan‐Derivaten mit Na2S2/AlCl3/H2CCl2, die sich zur 33S‐Isotopenmarkierung eignet. Nach geometrie‐optimierten closed und open shell MNDO‐Berechnungen ist sowohl für H2C2S2 wie für H2C2S 2˙⊕ die Vierring‐Struktur bevorzugt; hohe Spindichte in der Disulfid‐Gruppierung erklärt die beobachteten großen g‐Faktoren und 33S‐Koppungskonstanten.

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