Dialkyl Carbonate Synthesis Using Atmospheric Pressure of CO₂

Area of Science:

• Green Chemistry
• Catalysis
• Organic Synthesis

Background:

• Dialkyl carbonates (DRCs) are industrially important chemicals.
• Current synthesis methods often rely on hazardous phosgene or require high-pressure CO2.
• Existing CO2-based routes are costly due to CO2 purification and high-pressure requirements.

Purpose of the Study:

• To develop an environmentally friendly and cost-effective method for DRC synthesis.
• To utilize low-concentration and low-pressure carbon dioxide (CO2) as a feedstock.
• To avoid the use of halogenated alkylating agents.

Main Methods:

• A dehydration condensation reaction was employed.
• The process uses alcohols, tetraalkyl orthosilicates as dehydrating agents, and cerium dioxide (CeO2) as a catalyst.
• Monoalkyl carbonate intermediates were formed using a strong organic base.

Main Results:

• Diethyl carbonate yields of 39% and 30% were achieved.
• The synthesis utilized low concentrations of CO2 (15 vol%) at atmospheric pressure.
• The reaction proceeded efficiently without a large excess of reactants.

Conclusions:

• The developed method offers a sustainable pathway for DRC production from dilute CO2.
• This approach reduces costs associated with CO2 handling and purification.
• The process is viable under mild, atmospheric pressure conditions.