Kinetic modelling of the synthesis of diethyl carbonate and propylene carbonate from ethanol and 1,2-propanediol associated with CO2

Observed kinetics for the production of diethyl carbonate from CO2 and ethanol catalyzed by CuNi nanoparticles supported on activated carbon

Monometallic and bimetallic Cu:Ni catalysts with different Cu:Ni molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) were synthesized by wetness impregnation on activated carbon and characterized by TPR (temperature programmed reduction), XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy). The synthesized catalysts were evaluated in the gas phase production of diethyl carbonate from ethanol and carbon dioxide. The largest catalytic activity was obtained over the bimetallic catalyst with a Cu:Ni molar ratio of 3:1. Its improved activity was attributed to the formation of a Cu-Ni alloy on the surface of the catalyst, evidenced by XPS and in agreement with a previous assignment based on Vegard law and TPR analysis. During the reaction rate experiments, it observed the presence of a maximum of the reaction rate as a function of temperature, a tendency also reported for other carbon dioxide-alcohol reactions. It showed that the reaction rate-temperature data can be adjusted with a reversible rate equation. The initial rate as a function of reactant partial pressure data was satisfactorily adjusted using the forward power law rate equation and it was found that the reaction rate is first order in CO2 and second order in ethanol.

Carbon dioxide utilization in propylene carbonate production process

Utilizing carbon dioxide in chemical processes is one of the suggested remedies for reducing its atmospheric concentration. In this paper, the simulation of the propylene carbonate production process using 1,2-propanediol and carbon dioxide has been performed. The impact of temperature was examined between 75 and 400°C. It has been found that as temperature rises, reaction conversion increases. Additionally, the impact of recycling ratio was examined in the range of 0.1-0.5, which demonstrates that a rise in the recycle ratio results in a fall in conversion. Furthermore; it was observed that the pressure initially increases the solubility of carbon dioxide in 1,2-propanediol and improves the conversion of the reaction, but when enough carbon dioxide is supplied in the reaction, increasing the pressure does not affect the corresponding reaction. The effect of all studied parameters depends on the residence time of the reactants in the reactor. Investigating the interaction of parameters and optimizing the process has shown several optimal point of the process such as temperature of 295 °C, a recycle ratio 0.1, feed ratio 0.8 and a residence time of 12.61 h, with the related conversion being 59.6%.

Product Yield Increasing More Than 20 Times Achieved by Reducing Water Poisoning for Direct Diethyl Carbonate Synthesis

Diethyl carbonate (DEC) synthesis from CO2 and ethanol is a typical green chemical route for sustainable development and cleaner production. However, the bottleneck problem of a low DEC yield is still not solved at present. The DEC yield still maintains 0.5-5.0% unless expensive third additives are added. Compared to the cheap price of DEC, the third additives are generally more expensive. It is not advisible to use expensive chemicals to prepare cheap chemicals. In this work, the (ZrO2)1.0/(Fe2O3)1.0 catalyst was prepared by a novel template-precipitation method and the DEC yield of the DEC direct synthetic reaction only from CO2 and ethanol without third additives obtained 1.95%. After a series of supported catalysts were prepared, the DEC yield reached up to 46.1% for the (ZrO2)1.0/(Fe2O3)1.0@3A-CaO-CaC2 catalyst. This carrier can also be applied to other catalyst systems. CO2-TPD, NH3-TPD, and XRD were measured to analyze the microstructure and catalytic mechanism. Active center site theory was proposed to explain the intrinsic mechanism of catalyst activity. This new discovery of the mechanism and the DEC yield removed obstacles for the application of this reaction.

Catalytic CO2 esterification with ethanol for the production of diethyl carbonate using optimized CeO2 as catalyst

The direct conversion of (bio)ethanol and CO₂ is a promising route to diethyl carbonate (DEC) using CeO₂ from optimized catalyst synthesis procedure and cheap reactants originating from renewable resources in bioethanol production.