Kinetic Study on the One-Pot Synthesis of Dimethyl Carbonate in Supercritical CO₂ Conditions

Abstract

The kinetics of one-pot synthesis of dimethyl carbonate (DMC) was investigated using ethylene epoxide (EO), methanol, and CO 2 as raw materials and a mixture of KI and K 2 CO 3 as a catalyst under supercritical CO 2 conditions. The reaction pathway of the one-pot process is that EO first reacts with CO 2 to form ethylene carbonate (EC) and then EC reacts with methanol to produce DMC and ethylene glycol (EG). EC formation is a relatively fast reaction, whereas the transesterification of EC with methanol to form DMC is a relatively slow reaction and the ratecontrol step of the one-pot synthesis. 2-Methoxyethanol (ME), which is the exclusive byproduct, is predominantly formed by the reaction of EC with methanol. An isothermal kinetics model and an isobaric kinetics model for the one-pot synthesis of DMC were developed. The relative standard deviations of the models from the experiment data were less than (15% and (10%, respectively. The effects of temperature and CO 2 density on the reaction rates and selectivity were discussed.

Supercritical CO2 Extraction of Corn Stalk Pyrolysis Oil

“…All supercritical extraction experiments were conducted on a supercritical CO 2 extraction setup as described in [9], which mainly consists of a CO 2 reservior, a CO 2 delivering pump, an autoclave extractor (150 mL, 316 stainless steel) equipped with electromagnetic agitation and water-bath heating system, a separator (100 mL, 316 stainless steel) and a wet gas flow meter. The temperatures both for the extractor and the separator were measured by thermal couples and the pressures were gauged by manometers.…”

One-step synthesis of dimethyl carbonate from carbon dioxide, propylene oxide and methanol over alkali halides promoted by crown ethers

“…However, the formation of by-products such as 1-methoxy-2-propanol (1) and 2-methoxy-1-propanol (2) from the side reaction like methanolysis of propylene oxide (Scheme 3) is usually unavoidable. Furthermore, these catalysts are not highly effective [24] or stable [16,20,26], or are difficult to recycle [16,28,29], and need rigorous reaction conditions (e.g., high pressure of supercritical CO 2 ) [21,27,28]. For example, most of supported catalysts present a lower yield of DMC (only 16.8%) [24] under a mild reaction condition (e.g., initial pressure of CO 2 : 3 MPa, mole ratio of methanol and epoxieds: 3:1), and the yield of DMC only reaches to 34% under a relative rigorous reaction condition (e.g., initial pressure of CO 2 : 8 MPa [19,22,23,25], mole ratio of methanol and epoxieds: 9:1 [23]), while the yield of DMC of 57% needs an especially rigorous reaction condition (e.g., initial pressure of supercritical CO 2 [21,27,28]: 16.5 MPa, mole ratio of methanol and epoxieds: 20:1 or even 40:1 [20,28]).…”

Pareto optimization of an industrial ecosystem: sustainability maximization

“…Available data: kinetic data presented by Cui et al (2004); sizing and optimization data presented by Monteiro et al (2009b); (n) DMC production from urea: methanol and urea react forming methyl carbamate, which reacts with methanol to generate DMC and NH 3 at 180°C with a yield of 45%.…”