Greener Dye Synthesis: Continuous, Solvent‐Free Synthesis of Commodity Perylene Diimides by Twin‐Screw Extrusion

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 K2CO3, 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 30×103 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.

Rapid Mechanochemical Synthesis of Amides with Uronium-Based Coupling Reagents, a Method for Hexa-amidation of Biotin[6]uril

“…Following these prominent earlier contributions, [24][25][26][27][28][29][30][31][32][33] we aimed to further expand the scope and synthetic utility of the mechanochemical amidation methods. The current research was impelled by three objectives: First, most of the amide coupling reagents are simply not efficient enough for a range of substrates, 8 which require expansion of the established one-step mechanochemical amidation protocols beyond the previously applied EDC; for that purpose, in this work we mapped the coupling efficiency of uronium-type reagents (COMU and TCFH, Scheme 1) on several carboxylic acid/amine pairs.…”

“…[22][23][24] In the area of amide synthesis, the benefits of solvent-free techniques have not remained unnoticed and have been previously demonstrated in numerous studies (Scheme 1). [25][26][27] For example, mechanosynthesis of various amides and peptides has been performed from a series of activated carboxylic acid derivatives, such as N-carboxyanhydrides; 28,29 N-hydroxysuccinimide esters; 30 Nacyl benzotriazoles. 31 N-Acyl imidazoles 32 and acyloxytriazine esters 33 have been produced mechanochemically from carboxylic acids prior to reacting with amines.…”

Rapid Mechanochemical Synthesis of Amides with Uronium-Based Coupling Reagents, a Method for Hexa-amidation of Biotin[6]uril

“…Following these prominent earlier contributions, [24][25][26][27][28][29][30][31][32][33] we aimed to further expand the scope and synthetic utility of the mechanochemical amidation methods. The current research was impelled by three objectives: First, most of the amide coupling reagents are simply not efficient enough for a range of substrates, 8 which require expansion of the established one-step mechanochemical amidation protocols beyond the previously applied EDC; for that purpose, in this work we mapped the coupling efficiency of uronium-type reagents (COMU and TCFH, Scheme 1) on several carboxylic acid/amine pairs.…”

“…[22][23][24] In the area of amide synthesis, the benefits of solvent-free techniques have not remained unnoticed and have been previously demonstrated in numerous studies (Scheme 1). [25][26][27] For example, mechanosynthesis of various amides and peptides has been performed from a series of activated carboxylic acid derivatives, such as N-carboxyanhydrides; 28,29 N-hydroxysuccinimide esters; 30 Nacyl benzotriazoles. 31 N-Acyl imidazoles 32 and acyloxytriazine esters 33 have been produced mechanochemically from carboxylic acids prior to reacting with amines.…”

Continuous, Large-Scale, and High Proportion of Bioinspired Phosphogypsum Composites via Reactive Extrusion

“…Given this, we propose that it is the process that allows adjusting and controlling the morphology of the gypsum crystal. As a process intensification technology, extrusion technology has been widely used to blend and process in the polymer [ 21 ], pharmaceutical [ 22 ], and food industries [ 23 ], and in inorganic and organic materials synthesis [ 24 , 25 ]. Extrusion technology has also been applied in the field of building materials, and gradually presents new development characteristics [ 26 , 27 , 28 , 29 , 30 ].…”