A tailored polymeric cationic tag–anionic Pd(ii) complex as a catalyst for the low-leaching Heck–Mizoroki coupling in flow and in biomass-derived GVL

Abstract

A new polystyrene-type resin loaded with pincer-type imidazolium ionic tag has been very effective in the immobilization of [PdCl4]2− palladium complex leading to a very low leaching of the metal during its use in flow.

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

“…Different strategies have been evaluated to develop precatalysts/ catalysts immobilized onto supported ionic liquid-like phases (SILLPs) [33][34][35][36][37][38]. In these systems, the microenvironment provided by the ionic liquid-like units can have a remarkable influence on the overall process, particularly on the catalytic activity and recyclability of the supported species.…”

Challenges and Directions for Green Chemical Engineering—Role of Nanoscale Materials

“…Due to their easy separation from the reaction mixture, heterogeneous systems based on metals, 17,18,19 acid 20 or base 21 catalysts have been developed using both organic and inorganic supports. Among the heterogeneous catalytic systems, nanomaterials and metal nanoparticles-based catalysts have been widely studied in the last ten years thanks to their high surface area.…”

“…Meeting this challenge, to reduce attrition and provide thermal and mechanical stability of heterogeneous supported catalysts, flow technology is proving an effective tool. 17,19,20,24,25 In addition, the use of a flow technology has multiple advantages including safety, temperature control, mixing of reagents in two phase systems, easy scale-up and space economy. The use of flow reactors reduces exposure to toxic intermediates or dangerous reagents or additives, allows operation at high temperature and pressure in a safer manner, and guarantees a cleaner reaction mixture minimizing metal leaching of the catalysts with subsequent minimization of purification waste.…”

“…The use of flow reactors reduces exposure to toxic intermediates or dangerous reagents or additives, allows operation at high temperature and pressure in a safer manner, and guarantees a cleaner reaction mixture minimizing metal leaching of the catalysts with subsequent minimization of purification waste. 17,19,24,25 Moreover, by increasing the number of combined flow reactors (the "numbering-up" approach) it is possible to scale-up processes without any of the common problems found in batch scale-up scenarios. Heterogeneous catalytic systems, based on nanomaterials with high surface energy, are ideal partners for flow technologies which can effectively be useful for the definition of greener processes.…”

Sulfenylation of Arenes with Ethyl Arylsulfinates in Water

“… 53 − 61 However, this sulfenylation of arene with sulfinic ester in water is rarely reported. As part of our continuing efforts using unconventional media in organic reactions, 62 − 75 herein we disclose a simple and environmentally friendly method for the synthesis of aryl sulfides via direct C–H sulfenylation of arenes with ethyl arylsulfinates in water ( Scheme 1 f).…”