Highly efficient synthesis of cyclic carbonate with CO₂catalyzed by ionic liquid in a microreactor

Abstract

The development of highly efficient processes for the cycloaddition of CO 2 with epoxides to produce five-membered cyclic carbonates is a very attractive topic. In this work, the cycloaddition of propylene oxide (PO) and CO 2 to give propylene carbonate (PC) is studied in a microreactor using a HETBAB ionic liquid catalyst. The microreactor performance is evaluated by studying the effects of different operating conditions, including reaction temperature, operating pressure, residence time, molar ratio of CO 2 /PO, and the catalyst concentration in PO. The process characteristics of the reaction concerning the gas-liquid mass transfer and the intrinsic kinetics perspectives are discussed. The results show that the residence time can be dramatically reduced from several hours in a conventional stirred reactor to about 10 s in a microreactor. The yield of PC at 3.5 MPa can reach 99.8% at a residence time of 14 s. The turnover frequency (TOF) value varies in the range of 3000 to 14 000 h −1 compared to 60 h −1 in the conventional stirred reactor. The space time yield (STY) or the overall reaction rate ranges from 650 to 4500 g prod. (g cat. h) −1 , which is much larger than the value [ca. 19 g prod. (g cat. h) −1 ] for the conventional stirred reactor. To some extent, the present study has also demonstrated the concept of 'Novel Process Windows'.

Phosphorus‐based Bifunctional Organocatalysts for the Addition of Carbon Dioxide and Epoxides

“…The utilization of the corresponding simple ammonium salt 7 a led to a somewhat improved yield while 7 b and 7 c gave results comparable to their phosphonium counterparts (entries [11][12][13]. In contrast to bifunctional organocatalyst 3 d-f the yield increased from I À < Br À < Cl À and followed the order of nucleophilicity.…”

“…[13] Especially in the presence of hydrogen-bond donors such as alcohols, [9a, 13e, 14] carboxylic acids, [15] silanols, [13d] chitosan, [16] cellulose, [17] b-cyclodextrin, [18] amino acids, [19] and amino alcohols [20] the addition of CO 2 and epoxides to the corresponding cyclic carbonate was significantly accelerated.…”

Enzyme immobilization on photopatterned temperature‐response poly (N‐isopropylacrylamide) for microfluidic biocatalysis

“…Meanwhile, flow rates affected the 3D structure in a microchannel formed by PNIPAAm. With the flow rate increased, the fluid flows might undergo interface separation or formed a recirculation zone due to the increased microchannel surface roughness by 3D structure . These changes of fluid flows could enhance the mass transfer and heat transfer in microchannels.…”

“…The structure provided enzymes with protection from extreme external environmental conditions, which reduced the effect of temperature changes on enzyme activity during the reaction. Thus, an increase in the reaction temperature exerts a pronounced positive effect . However, when the temperature exceeded 45 °C, a marked decline in isoquercitrin yield was observed because the higher temperature caused a decrease in enzyme activity and induced the decomposition of rutin into other products, which decreased the efficiency of enzymatic hydrolysis .…”

Freie Formen mit Textilbeton

“…The OH‐functionalized ammonium bromide 7 has been investigated previously as a catalyst in batch and continuous‐flow reactions, reaching turnover frequencies of 3000–14 000 h −1 for the cycloaddition of CO 2 and epoxides 11a. 17 For this reason, 7 was chosen as a benchmark for the catalysts 1 – 6 . Nevertheless, separation of 7 from the product is difficult because of the good solubility of this catalyst in propylene oxide (PO) and propylene carbonate (PC).…”