Kinetic investigations of styrene carbonate synthesis from styrene oxide and CO2 using a continuous flow tube-in-tube gas-liquid reactor

Organocatalytic and Halide-Free Synthesis of Glycerol Carbonate under Continuous Flow

“…The gas was provided by a gas cylinder through a double pressure regulator. To prevent CO 2 outgassing and to retain a homogeneous solution stabilizing the flow throughput, we employed a back-pressure regulator (BPR) after the packed bed reactor (PBR). , First, a stability test was carried out to examine how and if the applied pressure would change the nature of the homogeneous, swollen catalyst gel (Scheme , upper part). The results (SI) demonstrated that a stable gel structure can be maintained when the pressure inside the tube-in-tube reactor (outer tube region) is 3–8 bar at 60–70 °C while operating the back pressure regulator at 13.3–17.2 bar.…”

“…In these manifolds, the substrate contains, apart from an oxirane unit, a second functional group (typically an alcohol or amine group) that activates CO 2 to form a carbonic acid hemiester intermediate with increased nucleophilicity. This formal proton relay event allows for an intramolecular attack on the oxirane providing the heterocyclic target under essentially halide-free conditions (Scheme a). ,− Notable progress has also been noted in recent years in the continuous flow preparation of similar cyclic carbonates using mostly metal- and/or halide-based catalysts, − although Jamison et al nicely demonstrated the effective use of a combination of simple N -bromo-succinimide (NBS) and benzoyl peroxide as a binary organocatalyst at elevated temperature (120 °C) . In a separate study, the same authors reported a stoichiometric approach for the two-step transformation of several alkenes into their respective cyclic carbonates …”

Kinetics and mechanistic investigation of epoxide/CO2 cycloaddition by a synergistic catalytic effect of pyrrolidinopyridinium iodide and zinc halides

“…The conversion of SO to SC was determined by monitoring the intensity of epoxide peak at 876 cm -1 which decreased as a result of cyclic carbonate formation i.e., carbonate peak at 1800 cm -1 (Fig. S2) [53,54] . The FTIR intensity data points were also validated using GC chromatography.…”

Diethylene Glycol/NaBr Catalyzed CO2 Insertion into Terminal Epoxides: From Batch to Continuous Flow

“…[15] More recently, CF CO 2 insertion was performed in a tube-in-tube gas-liquid reactor comprised of a CO 2 permeable inner coil continuously fed by styrene oxide (SO) and a mixture of tetrabutylammonium bromide and zinc bromide (TBAB/ZnBr 2 as a homogeneous catalyst), surrounded by an external jacket pressurized with CO 2 : this configuration allowed a quantitative SO conversion under relatively mild conditions (T = 120°C, p(CO 2 ) = 6 bar). [16] Heterogeneous catalytic systems based on d-block metal catalysts were also employed for CO 2 insertion in CF conditions. For instance, NbCl 5 and the ionic liquid 1-hydroxypropyl-3-nbutylimidazolium chloride, supported on protonated carboxymethylcellulose (HBimCl-NbCl 5 /HCMC), were tested as catalysts for CO 2 insertion in a library of epoxides at T = 130°C and p(CO 2 ) = 15 bar (6 examples, yields = 68-99 %).…”