Greener Dye Synthesis: Continuous, Solvent‐Free Synthesis of Commodity Perylene Diimides by Twin‐Screw Extrusion. (29th January 2020) - Cao, Qun
Abstract: A continuous, scalable, and solvent‐free method for the synthesis of various naphthalic imides and perylene diimides (PDIs) using twin‐screw extrusion (TSE) is reported. Using TSE, naphthalic imides were obtained quantitatively without the need for excess amine reactant or product purification. With good functional‐group tolerance, alkyl and benzyl amine derived PDIs (incl. commercial dyes) were obtained in 50–99 % yield. Use of K2 CO3, enabled synthesis of more difficult aniline‐derived PDIs. Furthermore, an automated continuous TSE process for Pigments Black 31 and 32 is demonstrated, with a throughput rate of about 1500 g day −1, corresponding to a space time yield of about 30×10 3 kg m −3 day −1, which is 1–2 orders of magnitude greater than for solvent‐based batch methods. These methods provide substantial waste reductions and improved efficiency compared to conventional solvent‐based methods. Abstract : Farbstoffsynthese ohne Lösungsmittel : Ausgehend von einem „Beat and Heat"‐Verfahren wurde ein kontinuierliches, skalierbares und lösungsmittelfreies Verfahren zur Synthese verschiedener Naphthalimide (3 Beispiele) und Perylendiimide (PDIs, 21 Beispiele) mittels Doppelschneckenextrusion (TSE) entwickelt. Die TSE‐Methode bietet im Vergleich zu herkömmlichen lösungsmittelbasierten Methoden eine erhebliche Abfallreduzierung und bessere Effizienz.