Dimethyl Carbonate Synthesis from CO₂ and Dimethoxytin(IV) Complexes: The Anatomy of the Alkylation Step Viewed from DFT Modeling

Abstract

In line with promoting environmentally acceptable chemical processes, the direct catalytic conversion of CO 2 and methanol into dimethyl carbonate (DMC) is a target of current industrial interest. Despite breakthroughs to master thermodynamic limitations, the reaction mechanisms are not well understood for providing keys to boost rate and selectivity. Specifically, the pathways releasing DMC and regenerating the reactive alkoxy moiety are poorly justified. We herein address these steps by density functional theory modeling (DFT) with (CH 3 ) 2 Sn(OCH 3 ) 2 . The study complements our kinetics experiments and end-products characterization obtained from Bu 2 Sn(OCH 3 ) 2 counterpart. Indeed, DMC formation by an intermolecular process between two monomeric stannanes is preferred to that previously reported with the dimer. A following multistep process with methanol is advanced to regenerate the stannanes along with water, thereby promoting a catalytic cycle. Accordingly, dialkyltin(IV) organometallics are unique to promote such a sequence giving opportunity in reactor design to overcome catalyst poisoning as well as thermodynamics limitations.

Robust pyrrole-Schiff base Zinc complexes as novel catalysts for the selective cycloaddition of CO2 to epoxides

“…This assumption holds on our experience on our previous studies on Zn-Sal(ph)en and N4-Schiff-Base Zn(II) complexes [43,51,52]. The monomer has also been shown to be the active catalyst in dimethyl carbonate synthesis from CO 2 and dimethoxytin(IV) complexes, preferably to the dimer [56,57]. A study of the detailed mechanism will be the subject of further work.…”

CO2 Capture and Utilization Editorial

“…In addition, insights into the proposed mechanism that is catalyzed by the electrodes were provided by density functional theory (DFT) calculations . DFT modeling was also the tool used to understand the reaction mechanisms of the direct catalytic conversion of CO 2 and methanol to dimethyl carbonate (DMC) …”

Catalytic processes for the direct synthesis of dimethyl carbonate from CO2 and methanol: a review

“…5–7 The formation of chemicals that possess high oxidation states is considered to be a desirable strategy for the utilization of CO 2 from the green chemistry and energy management points of view. 8–11 Among them, the synthesis of DMC from CO 2 and methanol could be of importance for the chemical industry.…”