From CO Oxidation to CO₂ Activation:  An Unexpected Catalytic Activity of Polymer-Supported Nanogold

Abstract

A simple, clean, safe, and reproducible catalyst system, polymer-supported nanogold, was successfully developed for the fixation of CO2 to cyclic carbonate and for the carbonylation of amines to disubstituted ureas with unprecedented catalytic activity (TOF > 50 000 mol/mol/h and TOFP approximately 3000 mol/mol/h, respectively). To the best of our knowledge, it was the first to report that nanogold catalysts have exclusive catalytic activity for activation of carbon dioxide, and that the catalytic activity of the polymer-immobilized nanogold catalysts could be controlled by the particle size of the nanogold.

Carbon dioxide uptake as ammonia and amine carbamates and their efficient conversion into urea and 1,3-disubstituted ureas

“…Their traditional synthesis required unsafe chemicals such as phosgene or carbon oxide and Au or Pt catalysts [35][36][37][38]. In recent years the direct synthesis of substituted ureas has been accomplished with the non toxic and cheap carbon dioxide in the presence of different catalysts and dehydrating agents to increase the yield of reaction [39][40][41][42]. Ionic liquids in conjunction with a base (CsOH) or transition metal (Fe, Co, Ni, Cu, Zn) acetates were also employed as reaction medium and catalysts to obtain 1,3-disubstituted ureas in good yield [43][44][45][46].…”

Important Green Chemistry and Catalysis: Non‐phosgene Syntheses of Isocyanates – Thermal Cracking Way

“…Based on this mechanism, our group also carried out the related work, the disubstituted urea was firstly synthesized by polymer-immobilized nanogold catalyst and then alcoholysis over TiO 2 /SiO 2 catalyst. [61,62] In this way, the utilization of CO 2 as a carbonyl source for carbamate synthesis was realized via an efficient and environmentally friendly route to some extent.…”

Catalytic Processes for Chemical Conversion of Carbon Dioxide into Cyclic Carbonates and Polycarbonates

“…Compound 1d exhibited the highest catalytic activity among all the catalysts. And the reactions were carried out at approximately 0.34 MPa of CO 2 pressure and [75][76][77][78][79][80][81][82][83][84][85] o C in the presence of 1 equiv of DMAP with TOFs (turnover frequency) ranging from 127-254 h -1 . Then, García and co-workers [11] successfully realized the separation of the catalysts from the reaction mixture and the reuse of the (salen)-metal catalyst in the coupling reaction of CO 2 and epoxides to provide cyclic carbonates.…”

“…Sakakura and coworkers [83] reported cyclic carbonate synthesis from scCO 2 and epoxide over lanthanide oxychlo- [85] demonstrated that polymerimmobilized nano-gold catalysts had unprecedented catalytic activity for coupling epoxide and of carbon dioxide, with TOF > 50000 mol / mol / h for the synthesis of cyclic carbonate.…”