(Pd–CuCl₂)/γ-Al₂O₃: a high-performance catalyst for carbonylation of methyl nitrite to dimethyl carbonate

Abstract

(Pd–CuCl2)/γ-Al2O3 catalyst with excellent activity and selectivity was successfully developed for vapor-phase carbonylation of methyl nitrite to dimethyl carbonate (DMC).

Synthesis of High-Performance and High-Stability Pd(II)/NaY Catalyst for CO Direct Selective Conversion to Dimethyl Carbonate by Rational Design

“…Subsequently, palladium methoxy carbonyl intermediate can be generated via the insertion of the adsorbed CO molecule. 17,23,29,31 It was suggested that DMC is produced by the reaction between palladium methoxy carbonyl intermediates and MN from the atmosphere, while DMO is obtained by the coupling between two palladium methoxy carbonyl intermediates. 1,17,23,31 However, the outstanding question remains of why the Pd(II)based catalysts favor the creation of DMC, while Pd(0)-based catalysts favor DMO.…”

“…The peaks at 1720 and 1191 cm −1 are ascribed to the CO and C−O stretching vibrations of adsorbed *COOCH 3 intermediates. 29 Moreover, the peak at 1450 cm −1 is assigned to the C−H deformation of adsorbed *COOCH 3 intermediates on catalyst surface. Strong new peaks appear at 1770 and 1303 cm −1 with the passing of time, which are ascribed to the CO and C−O stretching vibrations of gaseous DMC product, respectively.…”

“…It is known that using the Pd­(II)-based catalysts lead to the generation of DMC, whereas the Pd(0)-based catalysts lead to DMO. − The palladium methoxy intermediate was generally considered to form first after the absorption of MN. Subsequently, palladium methoxy carbonyl intermediate can be generated via the insertion of the adsorbed CO molecule. ,,, It was suggested that DMC is produced by the reaction between palladium methoxy carbonyl intermediates and MN from the atmosphere, while DMO is obtained by the coupling between two palladium methoxy carbonyl intermediates. ,,, However, the outstanding question remains of why the Pd­(II)-based catalysts favor the creation of DMC, while Pd(0)-based catalysts favor DMO. We next conducted the DFT calculations to understand the molecular mechanism behind this selectivity.…”

“…To prevent the catalyst deactivation, chloride was usually introduced to suppress the reduction of Pd­(II) and the further aggregation of Pd(0). − However, chloride often quickly changes into the methyl chloroformate byproduct and leads to a rapid catalyst deactivation. , Moreover, chloride can contaminate DMC and corrode the reaction apparatus . On the other hand, the performance of existing chloride-free catalysts is highly influenced by the local environments of active species and the type of acidic sites on carrier .…”

Sulfonate-Grafted Metal–Organic Frameworks for Reductive Functionalization of CO2 to Benzimidazoles and N-Formamides

“…The final NH 3 desorption peak above 330 °C was indexed to strong acid sites, which is associated with the NH 3 adsorbed on Brønsted acid sites. 78,79 In the cases of UiO-66(Zr) and 3.2%-PS/UiO-66(Zr), a broad desorption signal was observed between 150 and 330 °C, suggesting the presence of rich medium acid sites. The amount of NH 3 desorbed from these acid sites was calculated by integrating the area under the TPD curves.…”