In Situ Carbonylative Synthesis of Aromatic Esters and Formation of Quinazoline-2,4(1H,3H)-diones by Chemical Fixation of CO2 in Assistance of Polymer-Supported Palladium Catalyst

Abstract

In this work, a functionalized chloromethylated polystyrene supported polymer complex of palladium was designed and synthesized in the three-step process. The synthesized heterogeneous Pd(DAP-DEAS-MERF) catalyst was characterized by Field emission scanning electron microscopy, Energy dispersive analysis of X-rays, Elemental mapping, Atomic absorption spectroscopy, N2-BET adsorption-desorption isotherm, High-resolution transmission electron microscopy, Thermogravimetric analysis-Differential thermal analysis, Powder X-Ray diffraction and Fourier-transform infrared spectroscopy. The calculated surface area of the synthesized Pd(DAP-DEAS-MERF) catalyst is 4.018 m2/g and palladium content is found to be 5.16 % from AAS analysis. After this, the synthesized catalyst was successfully applied for the synthesis of aromatic esters and quinazoline-2,4(1H,3H)-diones in high efficiency. Aromatic esters were synthesized by the in-situ carbonylative coupling reaction of iodobenzenes and phenols using chlorofirmand KOH as CO source.In the case of quinazoline-2,4(1H,3H)-diones synthesis, CO2 fixation reaction was performed with 2-iodoaniline derivatives and tert-butyl isocyanide/cyclohexyl isocyanide under atmospheric CO2 pressure. The synthesized products were identified by 1HNMR spectroscopy after purifying by coloum chromatography technique. In this report, Pd(DAP-DEAS-MERF) catalyst proved its efficiency by providing a comparatively better reaction condition than the other reported homogeneous and heterogeneous catalytic systems. Additionally, the catalyst isrecyclable up to six times and thermally stable up to 319 °C.