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In this work, the kinetics study on the reaction between CO2 and tertiary amine catalyzed by zinc(II)‐1,4,8,11‐tetraazacyclotetradecane complexes (CM) and zinc(II)‐1,4,7,10‐tetraazacyclododecane complexes (CN) was carried out in a stopped‐flow device. The effects of the catalyst concentration, type of tertiary amines, and temperature on the reaction rate (ν) and catalytic activity (φ) were studied. It was found that the catalyst concentration, tertiary amine with higher pKa, and temperature had positive effects on ν. ν in N‐methyl diethanolamine solution with 10.0 mol m−3 CM and CN were 16.62 and 26.05 folds than the uncatalyzed ν at 298 K, respectively. φ increased with increasing catalyst concentration, decreasing temperature and tertiary amine's pKa. In addition, the kinetics behavior of tertiary amine‐CM/CN‐CO2 systems conformed to the Michaelis–Menten model. The activation energies in catalytic systems were 4%–15% lower than that in the non‐catalytic systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effects of operating conditions on ADA conversion rate and product composition were investigated. • DFT calculation indicated that the ADA ammoniation belongs to the Monomolecular Mechanism. • The expression of reaction kinetics was obtained at different reaction temperatures. Adiponitrile (ADN), a key precursor for the production of nylon 66, can be synthesized via adipic acid (ADA) ammoniation. The decrease in ADA cost has made this route an alternative route to prepare ADN recently. However, studies on the reaction kinetics and mechanism of this method were scarce, which limits the development of ammoniation reactors. In this study, reaction kinetics and mechanism of ADN preparation by ADA ammoniation were carried out. First, the operating conditions including reaction temperature, phosphoric acid (H 3 PO 4) dosage, ammonia (NH 3) volume content and stirring speed were optimized. Then Gas Chromatography-Mass Spectrometer (GC–MS) and Density Functional Theory (DFT) were adopted to study the intermediates and mechanism. The Monomolecular Mechanism of a two-step dehydration process was proposed. Finally, the reaction rate constant equation of ADA ammoniation was first established. The result showed pre-exponential factor for the reaction was 387.41 L/(mol·s), and the activation energy was 3.44 × 104 J/mol. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-Pt NPs (0.051–0.126 wt% Pt) were first prepared in RPB without surfactant. • Synergistic effect between Pt and Ni and homogeneous dispersion of Pt were found. • CAL conversion of 97.2% and HCAL selectivity of 88.4% were achieved by Ni-Pt NPs. • Reaction rate obtained by Ni-Pt NPs is 2.94 times larger than that by Ni NPs. • The effect of parameters on CAL hydrogenation and kinetic model were studied. Catalytic hydrogenation of α,β-unsaturated aldehydes is an efficient way to provide chemical feedstocks. Herein, Ni-Pt nanoparticles (NPs) (0.051–0.126 wt% Pt) were first synthesized by liquid reduction without surfactant in a rotating packed bed to catalyze the hydrogenation of cinnamaldehyde (CAL). Catalyst characterizations show that despite the thin amount of Pt, the regional Ni-Pt alloy and uniform distribution of Pt on Ni NPs as well as the unambiguous defect sites were found on the prepared Ni-Pt NPs. These explain the good catalytic performance of CAL hydrogenation where CAL conversion of 97.1% with hydrocinnamaldehyde (HCAL) selectivity of 88.4% was obtained. The reaction rate obtained by Ni-Pt NPs (0.0768 mol⋅g−1⋅h−1) is 2.94 times larger than that by Ni NPs (0.0261 mol⋅g−1⋅h−1) while the selectivity is not affected. Additionally, we investigated different parameters on the effect of CAL hydrogenation. Further, the kinetic study on the hydrogenation of CAL was exposed. The pre-exponential factor and activation energy are 3.22 × 1011 and 90.99 kJ/mol, respectively. [ABSTRACT FROM AUTHOR]

Typically, silica-alumina zeolites are hydrothermally synthesized in the sodium-rich dense hydrogel systems with a relatively long crystallization time in industry. The fast and economical synthesis of silica-alumina zeolites is still a big challenge. Herein, we develop a universal method to tackle this issue using the rotating packed bed (RPB). An interesting phenomenon is found that gel-liquid interfacial areas in the zeolite precursor are obviously enlarged when RPB is employed, and thus the following crystallization rates of zeolites are greatly improved, especially for the initial nucleation process. Also, we successfully control the growth rates of silica-alumina zeolite by adjusting the gel-liquid interfacial areas. Furthermore, we find that the transfer rate of OH− and hydrated sodium ions from liquid part to gel phase is enhanced by RPB in the initial nucleation process, which greatly promotes the nucleation rate of zeolites. The density functional theory (DFT) calculations demonstrate that hydrated sodium ions can induce the dehydrogenation of Si–OH to generate reactive oxygen radicals, thus lowering the energy barrier of the polymerization reaction and consequently accelerating the nucleation process. Moreover, NaY, NaZSM-5, and NaA zeolites with larger surface areas and more pore volumes are successfully synthesized by this RPB-enhanced-interface strategy, and their crystallization processes are all greatly accelerated. The gel-liquid interfacial areas in the zeolite precursor are obviously enlarged when RPB is employed, which reduces the diffusion resistance of sodium ions from liquid to gel phase in the early period of zeolite nucleation. DFT calculations indicate that sodium ions can induce the dehydrogenation of Si–OH to generate the oxygen free radical, which lowers the energy barrier of zeolite nucleation. Thus, RPB-enhanced-interface strategy can effectively accelerate the nucleation and crystallization process of zeolite. [Display omitted] • Rotating packed bed (RPB) can effectively accelerate the growth process of zeolites. • Zeolites prepared with RPB exhibit relatively large surface areas and pore volumes. • The diffusion resistance of active species in the zeolite synthetic system can be reduced. • Sodium ions promote zeolite nucleation via inducing the generation of oxygen radical. [ABSTRACT FROM AUTHOR]

• The reaction kinetics of SO 2 and NaLa/water DES was firstly studied. • Desulfurization by NaLa/water DES was intensified by rotating packed bed (RPB). • A mathematic model was developed to describe the mass transfer process in RPB. • A satisfactory agreement was obtained between experimental and modeling results. As ionic liquids alternative, the deep eutectic solvents (DESs) are expected to realize green and efficient SO 2 recovery. In this work, the reaction kinetics of SO 2 and sodium lactate (NaLa)/water DES was first studied. The reaction kinetic parameters, including order of reaction, rate constant, pre-exponential factor, and activation energy were determined. In view of the reaction characteristics, desulfurization intensification by high gravity technology was proposed. A mathematic model based on the reaction kinetics was developed to describe the SO 2 -DES mass transfer and reaction process in a rotating packed bed reactor. To validate this model, the desulfurization efficiency and mass transfer coefficient were measured under different operating conditions. It was demonstrated that SO 2 removal efficiency was above 99% under optimized conditions, realizing efficient SO 2 recovery. The validity of the proposed model was confirmed by the fact that most predicted mass transfer coefficients agreed well with the experimental results with deviations within ± 15%. [ABSTRACT FROM AUTHOR]