52 Cyclic carbonate synthesis from carbon dioxide and epoxide catalyzed by samarium oxychloride supported on zirconia

Tetramethylguanidine–silica nanoparticles as an efficient and reusable catalyst for the synthesis of cyclic propylene carbonate from carbon dioxide and propylene oxide

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

A series of Zn-Al composite oxides that were modified with alkaline earth metals, Zn-M-Al-O (M = Mg, Ca, Sr, and Ba) were fabricated via calcination of the corresponding hydrotalcite precursors, and evaluated as catalysts for the synthesis of propylene carbonate (PC) from CO2 and propylene oxide. Among the Zn-M-Al-O catalysts, Zn-Mg-Al-O (Zn/Mg = 4.0, pH = 10, without hydrothermal treatment) is the best in performance, showing PC selectivity of 99.2% and yield of 88.8% (140 °C, 12 h). Furthermore, the Zn-Mg-Al-O catalyst can be readily reused and recycled without any loss of activity in a test of five cycles. Through detailed studies of the basic nature of the Zn-M-Al-O catalysts, it was found that a moderate basicity (6.1 ≤ H 0 < 8.9) is beneficial to the cycloaddition reaction. The NH3- and CO2-TPD results also indicate that the Zn-Mg-Al-O catalyst has acid–base bifunctional properties, and a reaction mechanism is proposed. Zn-Mg-Al composite oxides were prepared via calcination of the corresponding hydrotalcite precursors, and used as catalysts for the synthesis of propylene carbonate from CO2 and propylene oxide. We achieved high catalytic efficiency under mild conditions, easy separation of catalyst from the product, and good recyclability of the catalyst. A plausible reaction mechanism has been proposed for the catalytic action.

A series of mixed‐linker metal‐organic frameworks(MIXMOFs) of the general formula Zn4O(BDC)x(ABDC)3–x has been synthesized and tested as catalyst in the reaction of propylene oxide (PO) and carbon dioxide. Based on MOF‐5 a new synthetic route was developed which allows the partial substitution of benzene‐1,4‐dicarboxylate (BDC) linkers in the material by functionalized 2‐aminobenzene‐1,4‐dicarboxylate. In that way the number of catalytically active amino groups can be tuned using the desired BDC/ABDC ratio. The presence of MIXMOFs (instead of a mechanical mixture of MOF‐5 and IRMOF‐3) was proven by high‐resolution X‐ray diffraction and DTG. XRD and TG/MS analysis revealed that pure MIXMOF materials can be obtained up to an ABDC loading of 40 %. The thermal stability in air is decreasing with increasing ABDC content from 450 °C for pure MOF‐5 (0 % ABDC) to ca. 350 °C for the 40 % MIXMOF Zn4O(BDC)1.8(ABDC)1.2. Consequently, MIXMOF materials represent a promising class of materials for catalytic applications in the temperature range at least up to 300 °C which is proven using the synthesis of propylene carbonate (PC) from propylene oxide and carbon dioxide as a test reaction. The catalytic results indicate that solid MIXMOF catalysts in combination with tetraalkylammonium halides (NR4X) as promoters are as active as the corresponding homogeneously dissolved reference compounds (H2ABDC, H2BDC and Zn salts) and that they can be recycled with only moderate loss in activity. A comparison of MIXMOFs from 0 to 40 % of ABDC revealed a dependence of activity on the number of amino groups. Due to the fact that even pure MOF‐5 catalyzed the reaction to some extent, surface Zn centers with free coordination sites might also contribute to substrate activation. Using optimized reaction conditions, a PC yield of up to 63 % can be obtained after 3 h in the presence of low catalyst concentration (0.045 mol‐% of 40 % MIXMOF, containing 0.05 mol‐% of NH2 groups).(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)

Several heterogeneous catalysts have been investigated for solvent-free synthesis of propylene carbonate (PC) for cycloaddition reaction of propylene oxide (PO) and carbon dioxide (CO2). The characterization of different heterogeneous catalysts has been successfully carried out using Raman spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. Batch cycloaddition reaction of PC and CO2 has been conducted in a high pressure reactor. The effect of various parameters that could influence the conversion of PO and the selectivity and yield of PC such as catalyst types, catalyst loading, CO2 pressure, reaction temperature, and reaction time has been studied to find the optimum conditions and the best preferred catalyst for this reaction. Ceria and lanthana doped zirconia (Ce–La–Zr–O) catalyst has been found to be the most active and selective for synthesis of PC as compared to other heterogeneous catalysts that were tested as part of this research. Catalyst reusability studies have been con...

Quaternary ammonium salt-functionalized chitosan: An easily recyclable catalyst for efficient synthesis of cyclic carbonates from epoxides and carbon dioxide

Synthesis of dimethyl carbonate from methanol, propylene oxide and carbon dioxide over KOH/4A molecular sieve catalyst

Synthesis of dimethyl carbonate and glycols from carbon dioxide, epoxides, and methanol using heterogeneous basic metal oxide catalysts with high activity and selectivity

The direct synthesis of propylene carbonate (PC) from propylene oxide (PO) and carbon dioxide (CO2) without the use of solvents was investigated utilizing bimetallic Fe─Cu/SBA‐15 catalysts. The Fe─Cu/SBA‐15 catalyst was prepared using the sol–gel method and was thoroughly characterized for understanding the nanostructure, morphology, and chemical composition. The catalytic performance was assessed under mild reaction conditions, specifically at atmospheric CO2 pressure, using PO as the substrate. Key reaction parameters, including temperature, catalyst dosage, and reaction time, were systematically optimized. Among the catalysts tested, 5 Fe─Cu/SBA‐15 exhibited superior activity, achieving an impressive PO conversion of 87% and PC selectivity of 95% under optimized conditions. The addition of tetrabutylammonium bromide (TBAB) as a co‐catalyst is necessary for obtaining maximum product yields. Further, the synergistic interaction between Fe and Cu was investigated, revealing that both metal species serve as active sites in catalysis. This bimetallic mesoporous material shows high recyclability for the PC synthesis, suggesting a wider scope of this work.

Synthesis of chiral propylene carbonate via asymmetric ring opening of racemic propylene oxide by carbon dioxide on immobilized cobalt salen catalyst

Metal complexes bearing ONO ligands as highly active catalysts in carbon dioxide and epoxide coupling reactions

Synthesis of cyclic carbonates from CO2 and propylene oxide (PO) with deep eutectic solvents (DESs) based on amino acids (AAs) and dicarboxylic acids

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

The homogeneous dinuclear zinc catalyst going back to the work of Williams et al. is to date the most active catalyst for the copolymerisation of cyclohexene oxide and CO(2) at one atmosphere of carbon dioxide. However, this catalyst shows no copolymer formation in the copolymerisation reaction of propylene oxide and carbon dioxide, instead only cyclic carbonate is found. This behaviour is known for many zinc-based catalysts, although the reasons are still unidentified. Within our studies, we focus on the parameters that are responsible for this typical behaviour. A deactivation of the catalyst due to a reaction with propylene oxide turns out to be negligible. Furthermore, the catalyst still shows poly(cyclohexene carbonate) formation in the presence of cyclic propylene carbonate, but the catalyst activity is dramatically reduced. In terpolymerisation reactions of CO(2) with different ratios of cyclohexene oxide to propylene oxide, no incorporation of propylene oxide can be detected, which can only be explained by a very fast back-biting reaction. Kinetic investigations indicate a complex reaction network, which can be manifested by theoretical investigations. DFT calculations show that the ring strains of both epoxides are comparable and the kinetic barriers for the chain propagation even favour the poly(propylene carbonate) over the poly(cyclohexene carbonate) formation. Therefore, the crucial step in the copolymerisation of propylene oxide and carbon dioxide is the back-biting reaction in the case of the studied zinc catalyst. The depolymerisation is several orders of magnitude faster for poly(propylene carbonate) than for poly(cyclohexene carbonate).

Synthesis of cyclic carbonates from epoxides and carbon dioxide over silica-supported quaternary ammonium salts under supercritical conditions