Direct Synthesis Of Diethyl Carbonate Research Articles

Dehydration by Pervaporation of an Organic Solution for the Direct Synthesis of Diethyl Carbonate

Pervaporation has been a central subject in the research community within the scope of the further development of energy- and cost-efficient alternatives to conventional liquid–liquid separation technologies. The potential eligibility of four commercial membranes (ZEBREX ZX0, PERVAPTM 4155-80, PERVAPTM 4100, PERVAPTM 4101) for use in an integrated dehydration application of a diethyl carbonate/water/ethanol mixture by pervaporation was assessed experimentally. The impact of feed concentration, operating temperature, pressure, and sweep gas flow rate on membrane separation performance, including permeation flux, permeate quality, selectivity, and permeance, was thoroughly investigated. Applying the ZX0 membrane delivered the best qualities of all tested membranes of the permeate stream, with a water concentration of mostly >98%. In comparing the water flux, the ZX0 membrane remained reasonably competitive with the polymer membranes. Furthermore, the sweep gas volume flow rate and the operating temperature were identified as influencing the flux significantly but not the product composition. At the same time, the feed concentration of water also influenced the water purity within the permeate. The experiments were monitored with a partial least squares model, allowing a quick assessment of obtained samples while delivering accurate results.

Sustainable synthesis of diethyl carbonate from carbon dioxide and ethanol featuring acetals as regenerable dehydrating agents

Featuring the regeneration of the dehydrating agent in the direct synthesis of diethyl carbonate offers a promising prospective in industrial application for the development of organic carbonate synthesis from CO2.

Mechanistic insights into CeO2-catalyzed direct synthesis of diethyl carbonate from CO2 and ethanol assisted by zeolite and 2,2-diethoxypropane

A mechanistic study on the production of diethyl carbonate on a CeO2 catalyst assisted by H-FAU and 2,2-diethoxypropane was conducted based on detailed kinetics.

Zr0.1/(Fe[sbnd]Ce) as highly efficient catalyst for direct synthesis of diethyl carbonate from ethanol with fermentation tail gas as CO2 raw material

In the production process of bioethanol, stripping is usually required to improve the production efficiency of ethanol, and the generated CO2 fermentation gas direct emissions contribute to increased carbon. Herein, we prepared Zrx/(FeCe) catalyst by co-precipitation method to catalyze CO2 and ethanol for production of diethyl carbonate (DEC). Compared with FeCe catalysts, the introduction of Zr significantly improved the acid-base active sites and the oxygen vacancies on the catalyst surface, resulted in higher activity and selectivity of the catalysts. The ratio of Zr:(FeCe) in the catalyst, reaction temperature, pressure and time were optimized, resulting a high DEC selectivity of 96.7% under the Zr0.1/(FeCe) catalyst. Finally, we used the fermentation tail gas as CO2 source to react with ethanol for the formation of DEC, and obtained 56.0% selectivity of DEC. This study provides a new idea for the utilization of CO2 fermentation gas and the development of cleaner fuel production process.

Effective synthesis of dialkyl carbonate from CO2 and alcohols using dibutyltin(IV) oxide catalyst and dehydrating agents

The combination of a dibutyltin(IV) oxide catalyst with an ortho ester as the dehydrating agent exhibited high activity for the direct synthesis of diethyl carbonate from CO2 and ethanol in 78% yield. With water as a by-product limiting the reaction, a recoverable dehydrating agent is required. When alkoxysilanes were employed for this purpose, various dialkyl carbonates were obtained in yields of 33–45%.

Synthesis of diethyl carbonate from CO2 and orthoester promoted by a CeO2 catalyst and ethanol

The combination of a CeO2 catalyst and ethanol effectively promotes the direct synthesis of diethyl carbonate (DEC) from CO2 and an orthoester. The reaction temperature, initial CO2 pressure, and the ethanol/orthoester volume ratio were found to significantly influence DEC formation and were systematically studied to determine the optimum conditions. DEC amount of 5.2 mmol was obtained at 160 °C, 5 MPa of CO2, and a reaction time of 20 h, providing high productivity (1.21 mmolDEC mmolcatalyst−1 h−1) using a CeO2 catalyst. The recovered CeO2 catalyst was recyclable at least four times without any significant loss of activity when both triethyl orthoacetate and triethyl orthovalerate were used. A series of orthoesters bearing various alkyl substituents, aromatic substituents and halide moieties were evaluated for their activities with and without ethanol. In the presence of ethanol, orthoesters bearing longer alkyl substituents led to higher DEC yields, and orthoesters bearing aromatic and halide moieties negatively impacted DEC formation. In the absence of ethanol, triethyl orthoacetate provided the highest DEC yield; in all cases, the use of ethanol resulted in a greater DEC formation than when the reaction was performed without ethanol.

An effective combination catalyst of CeO2 and zeolite for the direct synthesis of diethyl carbonate from CO2 and ethanol with 2,2-diethoxypropane as a dehydrating agent

The combination of CeO2 and H-FAU zeolite acted as an effective heterogeneous catalyst for the direct synthesis of diethyl carbonate from CO2 and ethanol with 2,2-diethoxypropane as a dehydrating agent.

Enhanced Conversion in the Direct Synthesis of Diethyl Carbonate from Ethanol and CO2 by Process Intensification

AbstractTo overcome the low equilibrium conversion in the direct synthesis of diethyl carbonate from ethanol and CO2 under moderate reaction conditions, the reaction was conducted in a membrane reactor packed with pelletized Cu‐Ni:3‐1 supported on activated carbon. A SiO2/γ‐Al2O3 commercial membrane and zeolite A membranes synthesized on commercial Al2O3 supports were evaluated in the membrane reactor. Although characterization of the membranes by X‐ray diffraction confirmed the presence of a zeolite A layer on the supports, gas permeation and permselectivity tests of ethanol and water evidenced some defects of the synthesized membranes. An increase in conversion with respect to a conventional packed‐bed reactor was observed in the membrane reactors prepared on Al2O3, but equilibrium conversion was not attained. However, with the commercial membrane, the ethanol conversion was higher than the equilibrium conversion.

Direct Synthesis of Diethyl Carbonate from CO<sub>2</sub> over ZnO@Na<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> Heterogeneous Material

At present, the world is facing two major problems: energy crisis and CO₂ emission. Diethyl carbonate is an effective gasoline additive which can greatly improve octane number. The route of diethyl carbonate synthesis from CO₂ is green and economical technique, which can effectively solve both energy crisis and CO₂ emission problems together. However, the design and preparation of catalysts is the core and key to realize the conversion from CO₂ to diethyl carbonate. This paper mainly described a novel synthesis of ZnO@Na₃PW₁₂O₄₀ heterogeneous material that applied in the direct synthesis of diethyl carbonate from CO₂ and ethanol. The special pore and channel structure of Na₃PW₁₂O₄₀ was used to maximize the catalytic capacity of ZnO material. The prepared catalysts were fully characterized by means of temperature-programmed desorption (TPD) and X-ray powder diffraction (XRD). The properties of acid-base sites on the surface of ZnO@Na₃PW₁₂O₄₀ were measured by temperature-programmed desorption technique. The catalytic performance over ZnO@Na₃PW₁₂O₄₀ heterogeneous material was examined on micro-reactor. The experiment results indicated that synthesized novel ZnO@Na₃PW₁₂O₄₀ heterogeneous material had large number of acid-base sites and high catalytic activity. This novel ZnO@Na₃PW₁₂O₄₀ catalyst had great ability to realize the effective conversion from CO₂ to diethyl carbonate. This technology not only improved the utilization rate of energy materials, but also reduced CO₂ emissions.

Direct synthesis of diethyl carbonate from ethanol and carbon dioxide over ceria catalysts

Direct synthesis of diethyl carbonate (DEC) from ethanol and CO2was investigated over “neat” and metal incorporated ceria catalysts. An optimal dependence (“volcanic plot”) of the catalytic activity on the acidity/basicity molar ratio was observed.

The efficient synthesis of diethyl carbonate via coupling reaction from propylene oxide, CO2 and ethanol over binary PVEImBr/MgO catalyst

Direct synthesis of diethyl carbonate (DEC) from propylene oxide, CO2 and ethanol via coupling reaction over a heterogeneous catalyst was demonstrated. In this work, a cross linked poly(ionic liquid) containing poly(1-vinyl-3-ethylimidazolium bromide)(PVEImBr) moiety was prepared via a free radical polymerization. Meanwhile, the MgO nanoplatelet with abundant basic sites was prepared, which was combined with PVEImBr to form a composite catalyst of PVEImBr/MgO. N2 physisorption, TG, XRD, SEM, CO2-TPD and FT-IR were conducted to thoroughly characterize the structure and texture of the catalysts. The as-prepared heterogeneous catalyst, which simultaneously possessed the dual function of nucleophilicity and basicity, was used in the coupling reaction of propylene oxide, CO2 and ethanol to synthesize diethyl carbonate and propylene glycol. The composite catalyst could promote the reaction with high efficiency, and a good catalytic performance of 54.4% diethyl carbonate yield and 59.8% propylene glycol yield could be achieved. The 1H NMR and DFT calculation disclosed that greatly faster reaction rate was ascribed to the synergistic effect between the BrƟ anion of PVEImBr and hydroxyl group of ethanol. Accordingly, a mechanism of the sequential reaction consisting of cycloaddition and transesterification steps was proposed.

Effect of Acidity, Basicity and ZrO2 Phases of Cu–Ni/ZrO2 Catalysts on the Direct Synthesis of Diethyl Carbonate from CO2 and Ethanol

Cu–Ni/ZrO2 catalysts with different Cu:Ni molar ratios were synthesized and tested in the direct synthesis of diethyl carbonate from carbon dioxide and ethanol. The effect of Cu:Ni molar ratio on the acidity and basicity of the catalysts was investigated using NH3 and CO2-TPD, respectively. Experimental results revealed that Cu:Ni-3:1/ZrO2 and Cu:Ni-2:1/ZrO2 samples exhibited the largest acidity and basicity, as well as the highest yield to diethyl carbonate. In particular, these catalysts displayed very-high selectivity (i.e., larger than 95 %) and activity (i.e., equilibrium conversions are attained). Additionally, XRD and Raman studies showed that structural and crystalline properties of ZrO2 were modified with Cu:Ni ratios of 3:1 and 2:1 (Cu:Ni-1:1/ZrO2, Cu:Ni-1:2/ZrO2) which was related to the improved catalytic activity in comparison to Cu:Ni-1:1/ZrO2, Cu:Ni-1:2/ZrO2, Cu:Ni-1:3/ZrO2 and ZrO2.

Direct Synthesis of Diethyl Carbonate from CO2 and Ethanol Catalyzed by ZrO2/Molecular Sieve

The synthesis of diethyl carbonate starting from ethanol and carbon dioxide was studied. The ZrO2 obtained by precipitation method was used as the catalyst. When the 3A molecular sieve was added as the co-catalyst, the DEC yield was effectively improved about 2.5-fold. The optimal mass ratio of ZrO2 and 3A molecular sieve was 5:2. In addition, the catalyst was characterized by the means of XRD, BET, TEM, NH3-TPD and CO2-TPD. It was indicated that the crystal type, acidic-basic properties of ZrO2, and the pore size of molecular sieve might be the main factors impacting the catalytic activities. By the optimization of the catalyst and the reaction operating conditions, when CO2 and ethanol were charged with the molar ratio of 514/225 mmol, the yield of DEC produced at 150 °C and 7.0 MPa was 0.384 mmol in 2 h with the selectivity of 85.1 %.

Highly efficient synthesis of diethyl carbonate via one-pot reaction from carbon dioxide, epoxides and ethanol over KI-based binary catalyst system

The synthesis of diethyl carbonate (DEC) directly from carbon dioxide, ethylene oxide (EO), and ethanol via one-pot reaction is reported for the first time. The effects of catalyst species and reaction variables on the synthetic performance of DEC were systematically studied. The integration of easily available KI and sodium ethoxide as homogeneous binary catalyst system was found to be very active for the one-pot reaction, and 63.6% of the DEC yield could be achieved under relatively mild reaction conditions (443K, 3MPa CO2 initial pressure, 2h). The byproduct of 2-ethoxyethanol, which is predominantly formed via alcoholysis of EO by ethanol through ring-opening reaction, was produced with small amount (<5%) under optimized conditions. Additionally, the thermodynamic evaluation reveals that the standard molar enthalpy of one-pot reaction is exothermic (ΔrHmθ=−19.70 kcal/mol<0). In comparison with the direct synthesis of DEC from CO2 and ethanol, the involvement of EO facilitates the formation of DEC, simultaneously with glycol produced. This strategy could also be successfully expanded to terminal epoxide substrates. Furthermore, a possible mechanism of the reaction was proposed on the basis of experimental results. This method provides a highly effective way to produce DEC via directly chemical utilization of CO2 and shows promising application in the manufacture of diethyl carbonate on an industrial scale.

Direct Synthesis of Diethyl Carbonate from CO2 and CH3CH2OH Over Cu–Ni/AC Catalyst

Cu–Ni/AC (Active carbon) catalysts were synthesized and characterized by temperature programmed reduction, X-ray diffraction, Scanning electron microscopy, chemical analysis, and N2 adsorption. Their activities (in terms of TOF) in the direct synthesis of diethyl carbonate from CO2 and CH3CH2OH were also evaluated. The presence of a Cu–Ni alloy phase may explain the significant increase in activity of bimetallic catalysts compared with monometallic samples.

Catalytic synthesis of diethyl carbonate by oxidative carbonylation of ethanol over PdCl 2/Cu-HMS catalyst

Direct synthesis of diethyl carbonate (DEC) by oxidative carbonylation of ethanol offers a prospective “green chemistry” strategy to eliminate the phosgene used in the traditional preparation processes. PdCl 2/Cu-HMS catalyst has been investigated, which demonstrated excellent selectivity to DEC by oxidative carbonylation of ethanol in the gas-phase reaction. The Si/Cu molar ratio of mesoporous Cu-HMS supports showed a remarkable effect on catalytic activities. An optimized Si/Cu molar ratio existed for catalytic performance, which was about 50/1. From XPS, ICP, XRD, nitrogen physisorption and IR characterization and analysis, it could be concluded that copper species incorporated into HMS frame and was highly dispersed in the frame of silica. The catalytic performances of PdCl 2/Cu-HMS were related with both Cu content in the Cu-HMS and the order degree of mesoporous structure for Cu-HMS.

Catalytic synthesis of dialkyl carbonate from low pressure CO 2 and alcohols combined with acetonitrile hydration catalyzed by CeO 2

Dialkyl carbonates have attracted much attention from the viewpoint of sustainable chemistry because they are useful intermediates and solvents and can be synthesized from renewable resources. One promising synthesis method of the dialkyl carbonates is the reaction of CO 2 with the corresponding alcohols. Direct synthesis of diethyl carbonate and dipropyl carbonate from ethanol + CO 2 and 1-propanol + CO 2 was promoted remarkably by the combination of acetonitrile hydration. The yield based on CO 2 reached 42 and 33% for diethyl carbonate and dipropyl carbonate, respectively. All the reactions were catalyzed by CeO 2 as a heterogeneous catalyst. It is characteristic that the combination with in situ dehydration enabled the conversion of low pressure CO 2 to dialkyl carbonate.

Crystal structures, acid–base properties, and reactivities of Ce xZr 1− xO 2 catalysts

Direct synthesis of diethyl carbonate from ethanol and CO 2 is attractive since starting materials are cheap and easily obtainable, and the initial operational procedures are quite simple. We present results showing that Ce x Zr 1− x O 2 solid solution catalysts are effective and selective for producing diethyl carbonate and could be recyclable without loss of any activity. High calcination temperature is favorable based on results of catalytic test. X-ray diffraction and temperature-programmed desorption of NH 3 and CO 2 provide evidence indicating that catalytic properties of Ce x Zr 1− x O 2 are closely dependent on the crystal structures and the acid–base sites on the surface with varied Ce/Zr ratios. Strong acid–base sites on the surfaces of catalysts are unfavorable for diethyl carbonate formation.