The transesterification of propylene carbonate (PC) or ethylene carbonate (EC) to dimethyl carbonate (DMC) by using catalytic reactive distillation (RD) is a promising approach for carbon dioxide utilization. However, there is still scarcity of comprehensive comparison between the two RD processes. Hence, using the UNIQUAC model and kinetics calibrated by literature and our experiments, we conduct an extensive comparison of the two RD processes. Based on the kinetic insights, laboratory RD processes for both reactions are modeled, analyzed, and experimentally validated. Consequently, two RD processes designed to produce 60 ktpy of DMC are optimized and compared. The interplay and control factors between reaction and separation are elucidated and clarified via investigating variations of the actual chemical equilibrium constant profile compared with theoretical values along the reactive section at various pressures, liquid holdups, etc. The results reveal that the optimized EC RD process achieves almost 50 % reductions in both total annual cost and carbon dioxide emission compared to the PC RD process. This work facilitates the carbon neutrality and provides an essential guide for quantitatively assessing the two routes.

The one-step methanol oxidation to dimethoxymethane (DMM) is a promising method for value-added chemical synthesis. However, vanadium cerium (VCe) catalysts commonly exhibit insufficient DMM selectivity in spite of its moderate high-temperature methanol conversion. In this work, titanium dioxide (TiO2) with relatively strong acidity was introduced into VCe catalyst to improve the catalysis performance of VCe. The results showed that the addition of TiO2 enhanced the oxidation reduction and surface acidity of the catalyst, and effectively improved the selectivity and yield of DMM. Furthermore, a scaled-up conceptual process for the one-step oxidation of methanol to DMM was explored, designed and economically evaluated based on the TiO2 modified catalysts. The entire conceptual process featured that multiple condensation-separation/absorption units offered a complete collection of the DMM. Through the optimization of the process, the generated products and unreacted methanol can be directly stripped from N2 and O2, and complete separation of DMM-methanol azeotrope was achieved with only one vacuum distillation unit. The entire process at what catalysis performance (methanol conversion, DMM selectivity, etc.) could bring profit was revealed and discussed. This study emphasizes the interaction between catalyst design, conceptual process design and economic evaluation, providing new ideas for the development of efficient industrial catalysts.