Synthesis Of Propylene Carbonate Research Articles

One-step condensation synthesis of di-tertiary ammonium salt protic ionic liquid for efficiently catalytic CO2 cycloaddition reaction under cocatalyst- and solvent-free conditions

A novel protic ionic liquid di-tertiary ammonium bromide ionic liquid (DTAB-IL) was synthesized by one-step condensation at 0 ℃ with 85 % yield. DTAB-IL also exhibited effective catalytic activity for CO2 cycloaddition without cocatalyst and solvent. The catalytic reaction conditions were optimized to 90 ℃, 4 h, 1 MPa, and the yield of propylene carbonate was obtained 96 % with high selectivity 99 %. Under the optimal conditions, DTAB-IL catalyst exhibited good recyclability and universality to various epoxides. Furthermore, temperature influence and kinetic investigation for propylene carbonate synthesis were studied. The activation energy for DTAB-IL catalyzing CO2 cycloaddition reaction was 43.93 kJ/mol, and the reaction was found to follow first-order for propylene oxide. Efficient cycloaddition reaction of CO2 and epoxide was attributed to the activation of epoxide and CO2 by di-tertiary ammonium and epoxide ring-opening by bromide anion in DTAB-IL.

Simulation and optimization of DMC synthesis process based on conventional and advanced exergy analyses

Dimethyl carbonate has received more and more attentions as an organic solvent in electrolytes. Aiming at the problem of high energy consumption in the process of dimethyl carbonate (DMC) production, the root of the problem was analyzed by using exergy analysis, which provides a theoretical basis for the construction of energy-saving process. Firstly, the overall process of DMC production was constructed, including propylene carbonate (PC) synthesis, DMC synthesis, azeotrope separation and propylene glycol (PG) purification processes. Secondly, the conventional and advanced exergy analyses of the four proposed processes were carried out. The distributions of exergy and exergy destruction were obtained through conventional exergy analysis. The exergy destructions were further divided through advanced exergy analysis, and the avoidable parts were focused on. Based on the above analyses, the corresponding heat integration processes were proposed. Finally, the conventional processes and the heat integration processes were evaluated with the performance indicators of the exergy destruction, total annual cost (TAC), total energy consumption (TEC) and CO2 emissions.

Incorporation of Mg/Al metal oxide into ionic liquids for CO2 capture and conversion into cyclic carbonate under solvent-free conditions: Effect of coordination ability, recyclability, and catalytic study

The direct conversion of carbon dioxide (CO2) and propylene oxide (PO) into propylene carbonate (PC) offers a green way to utilize anthropogenic CO2. However, this reaction is limited by low conversion of PO and harsh reaction conditions. In this study, we solve this problem using ionic liquids (ILs)/metal oxide composites (ILs@MAO). The catalytic activity of MAO-500 (500 = annealing temperature) is poor evidenced by its low conversion of PO (24.94%). However, ILs@MAO-500 has a high conversion of PO (97.54%) under similar reaction conditions (2 h at 1.5 MPa CO2 pressure, 90 °C, and 0.85 g catalyst). The ILs consist of imidazolium cation with weak coordinated [NTf2]– anion leading to outward movement of anion resulting in the formation of “heterodinuclear complex”. This complex generates an amorphous-crystalline intermediate with balanced acid-base sites that activate PO and stabilize the catalytic intermediate. In large part, the high PO conversion is theorized to be primarily due to the abundant reactive sites in the ILs that are covalently immobilized on the MAO-500 carrier. Furthermore, even after multiple recycling, ILs@MAO-500 remains stable and exhibits high yield and selectivity. The proposed solvent-free catalytic system is mild, kinetically fast, and naturally safe for coupling CO2 and PO into PC synthesis.

Mesostructured Bifunctional ZnBr2/g‐C3N4 Catalysts Towards Efficient Cocatalyst‐Free Cycloaddition of CO2 to Propylene Carbonate

AbstractCatalytic cycloaddition of CO2 with propylene oxide (PO) is a sustainable pathway for the synthesis of propylene carbonate (PC), and the design of efficient heterogeneous catalysts is a hot research topic in both C1 chemistry and functional materials. In this work, graphitic carbon nitride (g‐C3N4) materials were prepared using urea (U) and melamine (M) as precursors through one‐step thermal condensation and then applied as catalyst supports for ZnBr2. As heterogeneous catalysts, the synthesized composites (ZnBr2/g‐C3N4‐MU) exhibited higher activity in the cycloaddition reaction of CO2 to PC than ZnBr2/g‐C3N4‐M and ZnBr2/g‐C3N4‐U. The preparation temperature of ZnBr2/g‐C3N4‐MU could affect the distributions of nitrogen species and acidic strength, which thus determined the final catalytic activity. More importantly, the loading of ZnBr2 not only introduced acidic sites but also enhanced the strength of alkaline sites of g‐C3N4‐MU, enabling ZnBr2/g‐C3N4‐MU materials as acid–base bifunctional catalysts in cycloaddition of CO2 with PO.

MnO2 as efficient and robust catalyst for halogen-free synthesis of cyclic carbonate from CO2 and epoxides

Cyclic carbonate is an important fine chemical/intermediate and their synthesis from CO2 and epoxides is economical and green pathway, however, it is still a challenge to develop a efficient and robust catalyst for halogen-free synthesis of cyclic carbonate. Herein, we successfully prepared large-scale MnO2 catalysts by microfluidics method, and the MnO2 especially δ-MnO2 showed >99.9 % propylene carbonate yield under 393 K, 3 MPa CO2 and DMF solvent. Moreover, the initial TOF value over δ-MnO2 on the basis of total catalyst amount was 5.80 h−1, which was the maximum among all the reported heterogeneous metallic oxide catalysts for halogen-free synthesis of propylene carbonate from CO2 and epoxides, and the superior catalytic performance can be ascribed to the abundant moderate acidic–basic active sites on the δ-MnO2 surface and the synergistic effect of δ-MnO2 and DMF. Furthermore, the δ-MnO2 can be reused at least 4 times and exhibited wide substrate applicability.

One-Pot Synthesis of Propylene Carbonate through Tandem Epoxidation-Cycloaddition Reaction from Propylene and CO2

One-Pot Synthesis of Propylene Carbonate through Tandem Epoxidation-Cycloaddition Reaction from Propylene and CO₂

Propylene carbonate synthesis routes using CO2: DFT and thermodynamic analysis

Propylene carbonate (PC) is utilized to improve performance and stability in lithium-ion batteries as an electrolyte component and as a high-performance solvent in paints, varnishes, and adhesives. It is a versatile chemical used in many different industries. It also functions as a plasticizer in polymers and a solvent in pharmaceutical and cosmetic formulations. In the current work, chemical equilibrium analyses of a number of potential processes involved in the synthesis of PC were conducted. To examine the thermodynamic viability of all five approaches, the fluctuation of ΔGmo with temperature for the key processes of PC synthesis was investigated in a specific temperature range of 25 °C-180 °C and at 1 bar and 60 bar pressures. The heat capacity values were estimated using the Rozicka-Domalski method. Benson Group-Increment Theory (BGIT) was used to evaluate the unknown ΔfH for a molecule. By examining the impact of temperature (25 °C-180 °C) and pressure (0–100 bars) on chemical equilibrium constant and equilibrium conversion of reactants, the main reactions of PC synthesis pathways were compared. It was discovered that the one-pot synthesis route and the o-chloropropanol and CO2 approach were superior. The DFT calculations were performed to study the energy changes taking place to convert propylene, glycerol, and propylene glycol (PG) into PC. Both thermodynamic and DFT calculations proved that the PG and urea route is the least favorable for synthesizing PC.

Preparation of Schiff base metal catalyst and its catalytic synthesis of propylene carbonate from CO2

In recent years, research on the conversion of CO2 into fine chemical products has emerged as a prominent and dynamic area of study. In this study, four ligands were synthesized using salicylaldehyde, o-phenylenediamine, ethylenediamine, hexanediamine, and 2,6-diaminopyridine as precursors. Subsequently, these ligands were reacted with cobalt nitrate, zinc chloride, and aluminum chloride to synthesize 12 Schiff base metal complexes, which were employed as catalysts for the synthesis of propylene carbonate from CO2 and epichlorohydrin. The findings reveal that the SF-L/Co catalyst demonstrated superior performance, potentially attributed to the robust chelating capability of Co, leading to the provision of more acidic metal centers. Characterization of SF-L/Co was conducted utilizing scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) techniques. Process conditions were optimized, resulting in the achievement of a 100% yield and selectivity of propylene carbonate under optimal reaction conditions, without the generation of any by-products. Furthermore, the catalyst exhibited remarkable reusability, demonstrating consistent catalytic activity over five successive cycles without a substantial decrease in performance.

Green and rational design of Ln4Zn2L2 heteromultimetallic complexes for mild and highly efficient CO2 conversion

Reasonable and high efficient utilization of carbon dioxide (CO2) has always been considered as a kind of green and sustainable development strategy. However, the efficient chemical conversion of CO2 into value-added products has been limited due to lack of efficient catalysts. Herein, two novel heterometallic hexanuclear complex catalysts (viz Nd4Zn2L2 (1) and Eu4Zn2L2 (2)) were designed and synthesized, which featuring unique hetero-multinuclear units. The heterometallic hexanuclear complex catalysts not only have multi-bimetallic catalytic sites (Ln3+ and Zn2+) which can absorb more molecules and be beneficial to the improvement of catalytic performance, but also have the potential to further expand the chemical fixation of CO2 with epoxides avoid the harsh reaction conditions. Using the synthesis of propylene carbonate (PC) by cycloaddition reaction of propylene oxide (PO) and CO2 as a model reaction, the as-prepared catalysts and catalytic system showed high turnover frequencies (TOFs) under the mild condition instead of harsh reaction conditions. More importantly, these catalysts can be reused to preserve the structure's integrity and retain their catalytic activity at the same level even after five rounds of catalysis. The excellent regeneration performance indicated that the as-prepared heterometallic hexanuclear complex catalysts can be reused many times. In addition, the catalytic system also exhibited a wide range of substrates for epoxide. These results predict that the proposed heterometallic hexanuclear complex catalysts and catalytic system have great potential toward CO2 adsorption and catalytic conversion. This work may build up a new synthetic route for tailoring more new heterometallic complex catalysts with excellent catalytic activity and applied in various fields of application.

Br-doped Ga2O3/MCM-41 catalyzed synthesis of propylene carbonate from carbon dioxide and propylene oxide

In this paper, Br-doped Ga2O3/MCM-41 has been synthesised for the reaction of CO2 and propylene oxide, which has the advantages of high efficiency, greenness and recyclability.

Salen–cobalt catalyzed degradation of polypropylene carbonate and its application in one-pot tandem synthesis of propylene carbonate

This study achieved catalytic degradation of polycarbonates and transformation of CO2 into propylene carbonate under ambient conditions.

Review on the recent advances in catalytic conversion of carbon dioxide for synthesis of cyclic propylene carbonate

Generation of carbondioxide in the atmosphere has increased considerably over the past decades due to the increase of industrialization. This led to the increase in the global temperature which affects the eco-system. It is essential to reduce the emission of carbondioxide in the atmosphere for which different researchers are working on re-utilization of the generated carbondioxide either by converting to different products or by trapping them as carbonates. Propylene carbonate is one of the chemicals that are synthesized by using CO2 as a reactant. Propylene carbonate has many applications as an end product and acts as intermediate for synthesis of other useful chemicals. Fixation of CO2 into propylene oxide for the synthesis of propylene carbonate is still a challenging task due to the high thermodynamic stability of CO2. Propylene carbonate can be synthesized by reacting CO2 with different high energy materials using different catalyst. This review is focused on providing an idea about different types of catalyst reported for synthesis of cyclic propylene carbonate using propylene oxide and propylene glycol as the starting materials. This review also provides the mechanism for conversion of CO2 to propylene carbonate by different catalyst and at various working conditions.

Oxidative carbonylation of propylene glycol to propylene carbonate by copper-based catalysts

BackgroundDevelopment of copper-based catalyst and associated reaction engineering for heterogeneous oxidative carbonylation of propylene glycol (PG) to optimize conversion and selectivity. Coupling reactions with reverse water-gas shift reaction is a good way of realizing CO2 utilization. MethodThe synthesis of propylene carbonate (PC) through the oxidative carbonylation of propylene glycol is carried out in a pressurized autoclave reactor using solid copper catalysts. Various types of copper and composite copper/ceria catalysts are prepared by coprecipitation or impregnation method. Significant findingsReaction temperature and the roles of sodium acetate (SA) and potassium iodide (KI) additives are systematically studied with pure copper to map out the optimum reaction condition, i.e., a 100 °C-reaction using 2.0 g of PG mixed with 8.0 g of solvent with 0.02 g of SA and 0.02 g of KI additives. Using this optimized condition, the copper and composite copper/ceria catalysts are investigated with the composite catalysts composed of metallic copper on ceria, showing the highest selectivity of 94.7% towards PC. These findings in this study should pave way for the development of practical industrial scale CO2 utilization processes.

Hydrotalcite-calcined derivatives doped by zinc: A nucleophile-modified multifunctional catalyst for synthesis of propylene carbonate by cycloaddition

The composition of hydrotalcite-calcined derivatives doped by Zinc was optimized by uniform design. This derivatives further modified by KI nucleophile promoted the catalytic performance in terms of activity, selectivity and stability. N,N-dimethylformamide was proved to be the best solvent for the cycloaddition through molecular simulation. The results of characterization showed that KI-modified derivatives had hydrotalcite phase and ZnO phase, and the elements with catalytic activity were uniformly dispersed. The specific surface area of the derivatives was greatly increased after proper calcination, and it's positively correlated with the cycloaddition activity.The derivatives had acidic-basic properties, and the catalytic mechanism was proposed accordingly.

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide-Magnesium Oxide Catalysts.

A series of calcium oxide-magnesium oxide (CaO-MgO) catalysts were prepared under the effects of different precipitating agents and using varied Mg/Ca ratios. The physiochemical characteristics of the prepared catalysts were analyzed using XRD, FE-SEM, BET, FTIR, and TG/DTA techniques. Quantification of basic active sites present on the surface of the CaO-MgO catalysts was carried out using the Hammett indicator method. The as-prepared mixed oxide samples were tested for propylene carbonate (PC) synthesis through the alcoholysis of urea with propylene glycol (PG). The effects of the catalyst composition, catalyst dose, reaction temperature, and contact time on the PC yield and selectivity were investigated. The maximum PC yield of 96%, with high PC selectivity of 99% and a urea conversion rate of 96%, was attained at 160 °C using CaO-MgO catalysts prepared using a Mg/Ca ratio of 1 and Na2CO3 as a precipitating agent. The best-performing catalysts also exhibited good reusability without any significant loss in PC selectivity. It is expected that the present study will provide useful information on the suitability of different precipitating agents with respect to the catalytic properties of the oxides of Ca and Mg and their application in the synthesis of organic carbonates.

A continuous process for cyclic carbonate synthesis from CO2 catalyzed by the ionic liquid in a microreactor system: Reaction kinetics, mass transfer, and process optimization

The reaction of CO2 and propylene oxide (PO) for the synthesis of propylene carbonate (PC) is an important reaction, but the reaction is generally carried out under high-temperature and high-pressure conditions due to the limitations of reaction kinetics and mass transfer. Here, we propose a novel microreaction system catalyzed by ionic liquids (ILs). The reaction processes (e.g., catalyst, temperature, pressure, gas–liquid flow rate, catalyst concentration, residence time) were optimized within microreactors of different inner diameters. The kinetics for carbonate synthesis with CO2 catalyzed by ionic liquid (IL-[HMIM]Br) in a microreactor was evaluated, and the activation energy of [HMIM]Br was obtained. Based on the rough numerical estimation of mass transfer characteristics, coupled with the reaction characteristics, the microreactor enhancement can reduce the reaction time for this fast reaction to minutes, typically several hours in conventional reactors. This provides new opportunities for enhancing gas–liquid reactions with typical mass transfer control and for CO2 utilization to achieve carbon neutrality.

Preparation of propylene carbonate by alcoholysis of urea from the perspective of homogeneous reaction: Influence of dissolution and precipitation of metal oxide catalysts

AbstractThe dissolution process of metal oxide catalysts in the alcoholysis of urea by 1, 2‐propylene glycol (PG) to the synthesis of propylene carbonate (PC) was investigated. It was found that the reaction was mainly catalyzed by homogeneous catalysts. The metal oxide reacted with ammonia and isocyanate acid, the decomposition products of urea, to form a complex and dissolved into the reaction system. The dissolved amount of catalyst was positively correlated with the PC yield by using different oxides and salts as catalysts. The Fourier‐transform infrared spectroscopy (FTIR) result of the catalysts reacting with urea showed that the dissolution‐precipitation process of the catalysts was related to the decomposition of urea. The results of catalytic test indicated that both the dissolved amount of catalysts and the structure of the complex affected PC yields. A reaction mechanism was proposed based on the results. From the mechanism, a complex catalyst with at least two ammonia ligands is better for this reaction.

Novel MOF catalysts based on calix[4]arene for the synthesis of propylene carbonate from propylene oxide and CO2

In this study, novel composite materials based on calix[4]arene with hydroxyl groups in the arene “bowl” (K-OH) and the aluminum(III) 2-aminoterephthalate metal organic framework (NH2-MIL-101(Al), MIL) have been synthesized according to in situ or “bottle around ship” strategy. The effect of the synthesis method, i.e., MW-assisted technique (MW) and the solvothermal procedure (Solv), on the structural, morphological, textural and catalytic properties of MIL/K-OH composites was demonstrated. Catalytic performance of the MIL/K-OH(MW) and MIL/K-OH(Solv) composites was studied in solvent-free coupling of CO2 and propylene oxide (PO) to produce propylene carbonate (PC) at 0.8 MPa of CO2 and 80 °C. The activity of the MIL/K-OH(Solv) catalyst was higher in comparison with MIL/K-OH(MW) material as a result of the differences in the textural properties. The binary system MIL/K-OH(MW)/[n-Bu4N]Br was demonstrated to be a promising catalyst for cycloaddition of CO2 to PO. In its presence, the conversion of PO was 77 % with 99 % selectivity towards PC at 1.2 MPa of CO2, 50 °C for 24 h.

Kinetic study of CO2 fixation into propylene carbonate with water as efficient medium using microreaction system

Carbon dioxide (CO 2 ) utilization and fixation have become one of the most important research areas nowadays due to the increase of global greenhouse effect. Cyclic carbonate, which is widely used in various fields, can be synthesized by fixation of CO 2 with epoxide in industry. Moreover, the synthesis of cyclic carbonate is a 100% atom economical reaction, which makes it eco-friendly and promising. To enhance the reaction efficiency and safety, a microreaction system was used as the platform for cycloaddition reaction. In this work, tetrabutylammonium bromide (TBAB) was chosen as catalyst, and propylene oxide (PO) as a mode substrate. Interestingly, the addition of water can increase the propylene carbonate (PC) yield and decrease the activation energy considerably, proving water as catalyst promoter for PC synthesis. PC yield and selectivity could reach 91.6% and 99.8%, respectively. The Influence factors and kinetic equation for CO 2 cycloaddition were obtained as well.

A novel supported ionic liquid membrane reactor for catalytic CO2 conversion

Converting CO2 into cyclic carbonates is one of the most promising ways to help mitigate global climate change. In this paper, we developed a novel supported ionic liquid membrane (SILM) that integrates reaction and gas permeation functions into a single unit for efficient synthesis of propylene carbonate (PC) under solvent-free, cocatalyst-free, and catalyst-free separation conditions. The catalytic stability of SILM was verified by batch experiments, and the structure, morphology and composition were characterized by XRD, SEM, and EDS. Also, the process parameters of continuous membrane catalysis were evaluated for PO conversion, PC selectivity, space-time yield and PO flux. By comparative analysis, polyvinylpyrrolidone (PVP) could not only effectively inhibit the loss of ionic liquid (IL), but also help to form a stable membrane layer. Characterization results confirmed that IL was basically concentrated in the top layer of γ-Al2O3 rather than the intermediate layer. Besides, the essential factors were identified to provide a feasible route for the large-scale conversion of CO2.