Interest in dimethyl carbonate (DMC), a saleable chemical destination of CO2, has grown significantly. DMC is an oxygenated octane-booster and a safer and nontoxic substitute of well-established methylating-carbonylating hazardous chemicals like dimethyl sulfate and phosgene. Considering the CO2 routes to DMC, the one commercially promising converts CO2 with ethylene oxide (EO) to ethylene carbonate (EC), which then reacts with excess methanol (MeOH) to DMC and ethylene glycol (EG). This indirect route (IR) apparently exhibits green chemistry attributes. It converts greenhouse gases (GHG) to valuables, such as EG, EC, and DMC. Apparently, it is not energy intensive; it has 100% atom economy without wastes. However, there is a massive energetic obstacle occluded in the separation of the azeotropic pair DMC–MeOH yet to be considered. This work assesses the technical, economical, and environmental IR flowsheet for CO2 conversion to DMC. Assessment of entrainers for extractive distillation of DMC–MeOH was accomplished for EG versus methyl–isobutyl–ketone. Process design, energy consumption, and GHG emissions were assessed and showed that both alternatives are profitable but gave negative chemical sequestration indexes. Their GHG emissions through energy consumption and purges overcome the chemical conversion of CO2 to DMC. The process alternative using EG as the entrainer exhibits higher profitability and better sustainability indexes.

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-The dynamics of flash drums is simulated using a formulation adequate for phase modeling with equations of state (EOS). The energy and mass balances are written as differential equations for the internal energy and the number of moles of each species. The algebraic equations of the model, solved at each time step, are those of a flash with specified internal energy, volume and mole numbers (UVN flash). A new aspect of our dynamic simulations is the use of direct iterations in phase volumes (instead of pressure) for solving the algebraic equations. It was also found that an iterative procedure previously suggested in the literature for UVN flashes becomes unreliable close to phase boundaries and a new alternative is proposed. Another unusual aspect of this work is that the model expressions, including the physical properties and their analytical derivatives, were quickly implemented using computer algebra.