Synthesis Of Dimethyl Carbonate Research Articles

Integrated Dft and Experimental Study on Co3o4/Ceo2 Catalyst for Direct Synthesis of Dimethyl Carbonate from Co2

Integrated Dft and Experimental Study on Co3o4/Ceo2 Catalyst for Direct Synthesis of Dimethyl Carbonate from Co2

The role of urea in regulating the structural properties of Zr–Sn-based oxide catalysts for direct synthesis of dimethyl carbonate from CO2 and methanol

Zr–Sn–O catalysts were prepared with urea as precipitant. It was found that the usage of urea had a crucial effect on the structure properties and the catalytic activity of direct synthesis of DMC from CO2 and methanol.

Cerium Doped Zr-Based Metal-Organic Framework as Catalyst for Direct Synthesis of Dimethyl Carbonate from Co2 And Methanol

Cerium Doped Zr-Based Metal-Organic Framework as Catalyst for Direct Synthesis of Dimethyl Carbonate from Co2 And Methanol

Catalytic processes for the direct synthesis of dimethyl carbonate from CO2 and methanol: a review

The present review aims to discuss strategies that have been recently explored by researchers to improve the yield of DMC in its direct synthesis from CO2 and methanol.

Improved Catalytic Performance of Pd-Nay Zeolite by Tunning Al Distribution for the Synthesis of Dimethyl Carbonate

Improved Catalytic Performance of Pd-Nay Zeolite by Tunning Al Distribution for the Synthesis of Dimethyl Carbonate

Molecular simulation and optimization of extractive distillation for separation of dimethyl carbonate and methanol

Dimethyl carbonate, an important green solvent, has garnered substantial attention in recent years. The routes for dimethyl carbonate synthesis include transesterification, alcoholation of urea by methanol, and oxidative carbonylation of alcohols. The transesterification process accounts for the largest proportion of dimethyl carbonate synthesis because it affords a high conversion rate of the raw materials, easy separation of the products, and is the most mature process. The azeotrope of dimethyl carbonate and methanol in the top of the columns used for preparing dimethyl carbonate by transesterification needs to be further separated. Herein, the optimal ionic liquid ([BMIM] [OTF]) for the separation of dimethyl carbonate and methanol via extractive distillation was determined by applying a molecular dynamics simulation algorithm and utilized in the separation process. As an efficient and green energy-saving process, pervaporation-assisted extractive distillation was further evaluated for the separation of dimethyl carbonate and methanol. The results showed that the pervaporation-assisted extractive distillation process offers economic benefits and has less environmental impact, and its total annual cost is 17.28% lower than that of the common extractive distillation process. Environmental analysis showed that carbon dioxide emissions, sulfur dioxide emissions, and nitric oxide emissions were reduced by 49.09% with this process. Therefore, this research has important guiding significance for the realization of the high-efficiency, energy-saving, and green separation of dimethyl carbonate and methanol in industries.

Atomic-level insights into the steric hindrance effect of single-atom Pd catalyst to boost the synthesis of dimethyl carbonate

Atomic-level insight into the unique catalytic capability of single-atom catalysts that distinguished from nanometer-sized counterparts is highly desirable for catalyst design and catalysis research. By synthesizing single Pd atoms supported on TiO2 as a catalyst, here we demonstrate a steric hindrance effect of single atoms induced by the unique isolation of single-atom active sites to achieve a remarkable enhancement on catalytic performance in the synthesis of dimethyl carbonate. Experimental results and density functional theory calculations reveal that such steric hindrance effect of single atoms favors the yield of the desired product dimethyl carbonate against further reacting with intermediates to form byproduct, because no extra Pd species around single Pd atoms provide active sites to further adsorb and activate substrates directly. The discovery of such steric hindrance effect is a valuable supplement to single-atom catalysis, and may promote single-atom catalysts to be widely applied in selective catalytic reactions.

La2O3 nanorods - reduced graphene oxide composite as a novel catalyst for dimethyl carbonate production via transesterification route

A highly efficient G/La heterogeneous catalyst comprising of reduced graphene oxide (rGO) and lanthanum oxide (La2O3) was developed using the in-situ hydrothermal technique. Four different catalyst samples with graphene content of 0.2, 0.5, 1.0, and 2.0 were prepared and tested against dimethyl carbonate synthesis (DMC) synthesis using the transesterification method. Structural analysis by scanning electron microscopy revealed that La2O3 displayed nanorod morphology. DMC synthesis results showed that G/La-3 composite with 1% graphene content outperformed others and showed the highest DMC yield of ~84% at 180 ºC. The excellent performance of G/La-3 was attributed to the synergistic effect of 2-D rGO and 1-D La2O3 nanorods, which showed the highest surface area of 76.54 m2/g. Moreover, the existence of acidic and basic active sites as identified by the temperature-programmed desorption (TPD) technique facilitates DMC production over the surface of G/La-3 catalyst. Recyclability and reusability experiments showed a gradual decrease in DMC yield owing to catalyst deactivation. It is expected that the present work provides valuable visions of the applicability of graphene/rare earth metal oxide heterogeneous catalysts in the given or similar chemical transformation processes.

Excess soluble alkalis to prepare highly efficient MgO with relative low surface oxygen content applied in DMC synthesis

The activities of various MgO catalysts, which were prepared from different methods such as hydration synthesis, thermal decomposition, combustion, sol–gel and co-precipitation, were conducted in dimethyl carbonate (DMC) synthesis via transesterification of ethylene carbonate with methanol. MgO-P-Na2CO3-3.14 synthesized by the excess Na2CO3 precipitation compared the best catalytic activity and stability, which could be reused for seven times without obvious deactivation. The DMC yield was as high as 69.97% at 68 °C. The transesterification reaction could be separated into two steps, and the samples obtained by NaOH precipitant exhibited better ring-opening capability, while the catalysts acquired by Na2CO3 precipitant displayed superior transesterification ability. The structure-performance relationship was evaluated by multiple characterization methods. The results indicated that the as-synthesized catalyst derived from dried precursors with more crystalline magnesium carbonate was favorable for the promotion of DMC yield, and MgO-P-Na2CO3-3.14 with more Mg-O pairs, which were the active center for the transesterification of 2-hydroxyethyl methyl carbonate (HEMC) intermediate with methanol, resulted in more moderately basic sites left that was in accordance with the DMC yield variation. MgO-P-Na2CO3-3.14 with greater BET surface area and mesopore volume, relative low surface oxygen content and larger moderately basic sites amount compared the excellent activity in DMC synthesis.

Effect of Cobalt Doping on the Stability of CaO‐Based Catalysts for Dimethyl Carbonate Synthesis via the Transesterification of Propylene Carbonate with Methanol

AbstractTo improve the stability of the a CaO catalyst with high activity in the synthesis of dimethyl carbonate (DMC) at low‐temperatures via the transesterification of propylene carbonate (PC) with methanol, a series of Co‐doped CaO nanoparticles were synthesized with different cobalt contents via the sol‐gel method, and the catalytic performance of these catalysts increased in the order of 0.7Ca0.3Co<0.8Ca0.2Co<CaO<0.95Ca0.05Co<0.9Ca0.1Co. The characterization results of BET, XRD, FT‐IR, SEM, TEM, CO2‐TPD and XPS indicated that the addition of cobalt to CaO could form a novel layered structure of the Ca3Co4O9 carrier, which favoured the formation of strongly basic sites and then improved the activation of PC and methanol. The catalytic activity of traditional metal oxide catalysts is lower than that of pure CaO; however, the initial activity of the novel layered structure of the 0.9Ca0.1Co catalyst reached 72.9 %, which is obviously higher than that of 65.8 % for CaO. Furthermore, the results of long‐term catalytic evaluation showed that the best 0.9Ca0.1Co catalyst exhibited a stable PC conversion of 95.4 % and DMC yield of 93.1 % at 65 °C even after 168 h in the reactive distillation reactor. The deactivation mechanism showed that the layered structure of Ca3Co4O9 could stabilize CaO and prolong the life of the catalyst.

Integrated and Metal Free Synthesis of Dimethyl Carbonate and Glycidol from Glycerol Derived 1,3-Dichloro-2-propanol via CO2 Capture

Dimethyl carbonate (DMC) and glycidol are considered industrially important chemical entities and there is a great benefit if these moieties can be synthesized from biomass-derived feedstocks such as glycerol or its derivatives. In this report, both DMC and glycidol were synthesized in an integrated process from glycerol derived 1,3-dichloro-2-propanol and CO2 through a metal-free reaction approach and at mild reaction conditions. Initially, the chlorinated cyclic carbonate, i.e., 3-chloro-1,2-propylenecarbonate was synthesized using the equivalent interaction of organic superbase 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) and 1,3-dichloro-2-propanol with CO2 at room temperature. Further, DMC and glycidol were synthesized by the base-catalyzed transesterification of 3-chloro-1,2-propylenecarbonate using DBU in methanol. The synthesis of 3-chloro-1,2-propylenecarbonate was performed in different solvents such as dimethyl sulfoxide (DMSO) and 2-methyltetrahydrofuran (2-Me-THF). In this case, 2-Me-THF further facilitated an easy separation of the product where a 97% recovery of the 3-chloro-1,2-propylenecarbonate was obtained compared to 63% with DMSO. The use of DBU as the base in the transformation of 3-chloro-1,2-propylenecarbonate further facilitates the conversion of the 3-chloro-1,2 propandiol that forms in situ during the transesterification process. Hence, in this synthetic approach, DBU not only eased the CO2 capture and served as a base catalyst in the transesterification process, but it also performed as a reservoir for chloride ions, which further facilitates the synthesis of 3-chloro-1,2-propylenecarbonate and glycidol in the overall process. The separation of the reaction components proceeded through the solvent extraction technique where a 93 and 89% recovery of the DMC and glycidol, respectively, were obtained. The DBU superbase was recovered from its chlorinated salt, [DBUH][Cl], via a neutralization technique. The progress of the reactions as well as the purity of the recovered chemical species was confirmed by means of the NMR analysis technique. Hence, a single base, as well as a renewable solvent comprising an integrated process approach was carried out under mild reaction conditions where CO2 sequestration along with industrially important chemicals such as dimethyl carbonate and glycidol were synthesized.

Surface reconstruction induced highly efficient N-doped carbon nanosheet supported copper cluster catalysts for dimethyl carbonate synthesis

N-doped hierarchical porous carbon nanosheets-supported copper catalysts (Cu/NCNS-x) were fabricated to solve the problem of deactivation caused by the leaching, agglomeration and oxidation of Cu nanoparticles (NPs) in the dimethyl carbonate (DMC) synthesis. The optimal Cu/NCNS-12 exhibited superb activity and stability without obvious deactivation after 10 cycles. The nanosheet structure produced new defects resulting in Cu reconstruction during the reaction process, while the strong interaction between Cu0 and N atoms greatly inhibited the oxidation of Cu0. The reconstruction of Cu was stimulated at above 100 °C, regardless of atmosphere, solvent types, pressure and rotation speed. The mechanism was elaborated that the initial Cu NPs (11 nm) migrated and then was trapped into newly created defects, finally formed into clusters (0.91 nm) as well as single-atom sites. This work provides profound potential in understanding metal reconstruction and developing a promising synthetic strategy of metal cluster catalysts.

Dimethyl carbonate (DMC) synthesis from methanol and carbon dioxide in the presence of ZrO2 solid solutions and yield improvement by applying a natural convection circulation system

In this study, we conducted an initial screening of ZrO2 and M/ZrO2 (M = Al, Ca, Ce, Pr, and Y) catalysts employing a batch apparatus first and then applied the selected catalyst (Ce0.1Zr0.9O2) into a natural convection circulation system with dehydrating agents, for the direct synthesis of dimethyl carbonate (DMC) from methanol (MeOH) and CO2. During the initial screening, Ce0.1Zr0.9O2 showed the highest DMC yield at ∼ 0.64% with 100% selectivity at 170 °C. The catalytic reactivities of ZrO2 and M/ZrO2 solid solutions followed the order: Ce/ZrO2 > Y/ZrO2 > Pr/ZrO2 ≈ ZrO2 > Al/ZrO2 > Ca/ZrO2. The relationship between physical properties and the activity of the catalysts was evaluated. As a result, the specific surface area and the acidity/basicity were considered to be irrelevant to the catalytic activity. However, a clear relationship between the temperature-programmed desorption (TPD) profile of MeOH and the reactivity was revealed: the increase of the weak affinity sites leads to the increase of reactivity. During the direct DMC synthesis over Ce0.1Zr0.9O2 catalyst employing the natural convection circulation system with molecular sieves 3A, the DMC yield reached up to 14.3% with 100% selectivity, which was the highest yield so far using M/ZrO2 catalysts. Prior to the experiment with the natural convection circulation system, the initial conditions were determined based on the experimental results employing the batch apparatus, previous literature, and estimation results. Moreover, some factors affecting the DMC yield using the circulation system were studied, including the reaction rate, the circulation rate of the flow in the circulation system, and the dehydration rate in the dehydration part.

Synthesis of Dimethyl Carbonate by Transesterification of Propylene Carbonate with Methanol on CeO2-La2O3 Oxides Prepared by the Soft Template Method.

In this study, CeO2, La2O3, and CeO2-La2O3 mixed oxide catalysts with different Ce/La molar ratios were prepared by the soft template method and characterized by different techniques, including inductively coupled plasma atomic emission spectrometry, X-ray diffraction, N2 physisorption, thermogravimetric analysis, and Raman and Fourier transform infrared spectroscopies. NH3 and CO2 adsorption microcalorimetry was also used for assessing the acid and base surface properties, respectively. The behavior of the oxides as catalysts for the dimethyl carbonate synthesis by the transesterification of propylene carbonate with methanol, at 160 °C under autogenic pressure, was studied in a stainless-steel batch reactor. The activity of the catalysts was found to increase with an increase in the basic sites density. The formation of dimethyl carbonate was favored on medium-strength and weak basic sites, while it underwent decomposition on the strong ones. Several parasitic reactions occurred during the transformation of propylene carbonate, depending on the basic and acidic features of the catalysts. A reaction pathway has been proposed on the basis of the components identified in the reaction mixture.

Continuous dimethyl carbonate synthesis from CO2 and methanol over BixCe1\u2212xO\u03b4 monoliths: Effect of bismuth doping on population of oxygen vacancies, activity, and reaction pathway

We evaluated bismuth doped cerium oxide catalysts for the continuous synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide in the absence of a dehydrating agent. BixCe1−xOδ nanocomposites of various compositions (x = 0.06–0.24) were coated on a ceramic honeycomb and their structural and catalytic properties were examined. The incorporation of Bi species into the CeO2 lattice facilitated controlling of the surface population of oxygen vacancies, which is shown to play a crucial role in the mechanism of this reaction and is an important parameter for the design of ceria-based catalysts. The DMC production rate of the BixCe1−xOδ catalysts was found to be strongly enhanced with increasing Ov concentration. The concentration of oxygen vacancies exhibited a maximum for Bi0.12Ce0.88Oδ, which afforded the highest DMC production rate. Long-term tests showed stable activity and selectivity of this catalyst over 45 h on-stream at 140 °C and a gas-hourly space velocity of 2,880 mL·gcat−1·h−1. In-situ modulation excitation diffuse reflection Fourier transform infrared spectroscopy and first-principle calculations indicate that the DMC synthesis occurs through reaction of a bidentate carbonate intermediate with the activated methoxy (−OCH3) species. The activation of CO2 to form the bidentate carbonate intermediate on the oxygen vacancy sites is identified as highest energy barrier in the reaction pathway and thus is likely the rate-determining step.

Efficient synthesis of dimethyl carbonate via transesterification of ethylene carbonate catalyzed by swelling poly(ionic liquid)s

The synthesis of dimethyl carbonate (DMC) via transesterification of ethylene carbonate (EC) and methanol (MeOH) was an environmental and practical strategy. Herein, poly(ionic liquid)s (PILs) with swelling abilities were synthesized by free radical copolymerization of N-vinylimidazolium ionic liquids, sodium 4-vinylbenzoate and cross-linker 1,8-triethylene glycoldiyl-3,3ʹ-divinylimidazolium bromide ([(EG)3-DVIm]Br2). The swelling abilities of PILs in various solvents were measured, and PILs could swell in methanol (MeOH). The swelling ability of PILs in MeOH could be modulated by changing the cross-linker content and chain length of 3-alkyl-substituents on imidazolium. The swollen state of PILs in MeOH presented a porous cross-linked network structure observed by the cryo-scanning electron microscope (cryo-SEM). The swelling PILs were used to catalyze the transesterification of ethylene carbonate (EC) and MeOH to prepare the DMC, and the catalytic activities was correlated with the swelling abilities of PILs. The PIL with 3-butyl-substituent and 2.5 mol% cross-linker (poly[VBIm-VBA-DVIm]-2.5%) had the highest swelling ratio (Q = 12.4 (g/g)) in MeOH and EC mixed solvents and exhibited excellent catalytic activities, which was similar to corresponding homogeneous ionic liquid. Furthermore, the catalyst could be reused up to seven runs without any considerable loss of its initial activity.

Synthesis of Dimethyl Carbonate from CO2 and Methanol over Zr-Based Catalysts with Different Chemical Environments

The adsorption and activation of both CO2 and methanol are mainly affected by the distance of the Lewis acid site, Zr4+, and Lewis base, Zr4+/O2−, of the Zr-based catalysts. In this paper, Zr-incorporated SBA-15 (Zr-SBA-15) and Zr-grafted SBA-15 (Zr/SBA-15) catalysts were prepared with different Zr environments, and were analyzed with N2 adsorption–desorption isotherms, X-ray diffraction, UV-vis spectra, and XPS. It was proposed that Zr-SBA-15 catalyst with Si-O-Zr-OH and Zr-O-Si-OH structure exhibited non-adjacent sites between Zr4+ and Zr4+/O2−, while Zr/SBA-15 catalyst with Zr-O-Zr-OH structure showed neighboring sites between Zr4+ and Zr4+/O2−. Furthermore, the Zr/SBA-15 catalyst exhibited good catalytic activity, while no DMC was detected over the Zr-SBA-15 catalyst at the same reaction conditions. For combined in situ infrared and catalytic performance, it was indicated that the methanol and CO2 could be activated to form DMC, only when the Zr4+ and Zr4+/O2− sites existed and were adjacent to each other in the Zr-O-Zr-OH of Zr/SBA-15 catalyst.

Design and optimization of reactive dividing-wall extractive distillation process for dimethyl carbonate synthesis based on quantum chemistry and molecular dynamics calculation

• Selection of extractants based on quantum chemistry and molecular dynamics calculation. • The process of dimethyl carbonate production by transesterification was designed. • Economic and environmental optimization of several different production separation processes. The preparation of dimethyl carbonate by transesterification of ethylene carbonate and methanol has an important application in industry. The preparation of dimethyl carbonate by reactive distillation and the efficient separation of dimethyl carbonate and methanol are the inevitable requirements of the sustainable development of extractive distillation. Based on the quantum chemistry calculation and molecular dynamics calculation analysis, a better extractant (2-Furaldehyde) was selected. The simulated extractive distillation was designed to separate dimethyl carbonate methanol. The σ - profile was drawn by using COSMO-SAC model, and three different separation processes of dimethyl carbonate production were compared and optimized. Taking TAC as the objective function, the separation process of reactive dividing-wall extractive distillation can reduce about 21% and carbon dioxide emission by about 10% compared with the common reactive distillation process, which has obvious economic advantages and environmental performance. Through the economic and environmental optimization analysis of the production and separation process of dimethyl carbonate, it provides a certain guiding significance for the actual production of dimethyl carbonate and the separation of dimethyl carbonate methanol.

One-Pot Synthesis of Dimethyl Carbonate over a Binary Catalyst of an Ionic Liquid and an Alkali Carbonate under Low Pressure.

A mild and highly efficient approach has been developed for the one-pot synthesis of dimethyl carbonate (DMC) from epoxide, carbon dioxide, and methanol under low initial pressure. The key to the successful transformation is the use of a bicomponent catalytic system composed of a hydroxyl-functionalized ionic liquid and an alkali carbonate. This bicomponent catalytic system demonstrated excellent reusability in four runs. Under the optimal reaction conditions, a 64% yield of DMC from propylene oxide and an 81% yield of DMC from ethylene oxide were obtained.

In Situ IR Studies on the Mechanism of Dimethyl Carbonate Synthesis from Methanol and Carbon Dioxide

The synthesis of dimethyl carbonate (DMC) from methanol and Carbon dioxide (CO2) has been investigated over 5% Rh/Al2O3 catalyst. Diffuse Reflectance Infrared Fourier Transfer Spectroscopy (DRIFTS) was used to probe the reaction adsorbates which showed that activation of methanol and CO2 involves generation of intermediate methoxy species and formate ingredients, participating in elementary steps of DMC formation. Formation of DMC involves parallel routes comprising interaction of the OH group of Al2O3 through an acid/base mechanism and formate pathway with participation of metal sites. DMC in acid/base pathway is formed via methoxy species to form methoxy carbonate (CH3O)CO2 (active adsorbate), which then reacts with the methyl species to form DMC. The pathway involving metal Rh sites generates an additional elementary step for the involvement of CO2 in the reaction through active formate species. The synergy of parallel pathways determines the performance of the 5% Rh/Al2O3 catalyst. Further improvement of catalyst performance should be based on such a feature of the reaction mechanism.