Fengli Yu

Polyether-substituted thiazolium ionic liquid catalysts – a thermoregulated phase-separable catalysis system for the Stetter reaction

A series of polyether-substituted thiazolium ionic liquids have been synthesized and used as catalysts in the Stetter reaction. The ionic liquids are a thermoregulated phase-separable catalysis (TPSC) system, because they possess the properties of critical solution temperature (CST) and inverse temperature-dependent solubility in toluene–heptane. The results showed that the novel TPSC system exhibits high recycling efficiency, and provides a potential route for a environmentally benign Stetter reaction.

Imidazolium chiral ionic liquid derived carbene-catalyzed conjugate umpolung for synthesis of γ-butyrolactones

A serial of imidazolium chiral ionic liquids starting from commercially available (−)-menthol as a chiral pool have been synthesized and successfully used for catalyzing conjugate umpolung of α,β-unsaturated aldehydes to stereoselectively synthesize γ-butyrolactones. The catalytic activities of these ionic liquids are examined and compared. The reaction of trans-cinnamaldehyde and p-methoxycarbonyl benzaldehyde as a model has been investigated in detail, and the reaction conditions have been optimized. Under the selected conditions, the ionic liquid catalyst can catalyze the annulations of trans-cinnamaldehyde with different aromatic aldehydes to afford differently substituted γ-butyrolactones. The recyclability of the ionic liquid catalyst is investigated, and the results have indicated that the catalyst can be recycled six times without obvious activity decreasing.

Selective hydrogenation of α-pinene to cis-pinane over Ru nanocatalysts in aqueous micellar nanoreactors

D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS-1000) stabilized Ru(0) nanoparticles were prepared and characterized. These nanoparticles were employed to selectively hydrogenate α-pinene to cis-pinane. With a small amount of Na2CO3 present, reaction rates could be increased significantly, and the reaction medium could be readily recycled. TEM, CLSM, IR and leaching experiments were employed to quantify the advantages of the catalytic system. The procedure is environmentally friendly. It offers a reference for the catalytic hydrogenation of other hydrophobic natural products.

Oxidative-extractive deep desulfurization of gasoline by functionalized heteropoly acid catalysts

A series of functionalized heteropoly acid catalysts with two PEG chains and an Anderson-type polyoxoanion IMo6O245− have been in situ synthesized, and applied for catalytic oxidative desulfurization coupling with extraction (oxidative-extractive desulfurization, OEDS). Two PEG chains endow the catalyst with a good extracting ability for sulfur compounds, particularly, their corresponding oxidative products. The oxidation and extraction can be performed simultaneously. No additional extracting agent is added after oxidation. The mechanism of OEDS is proposed. The effect factors for OEDS of model gasoline with H2O2 and O2 as oxidants are respectively investigated, and the optimum conditions are respectively obtained. The H2O2 OEDS system is more efficient, rapid and has low energy consumption. It just takes several tens of minutes under the mild conditions to achieve the complete removal of dibenzothiophene (DBT), benzothiophene (BT) and thiophene in model gasoline. The novel H2O2 OEDS system has been also applied for the desulfurization of real gasoline. The vast majority of sulfides in real gasoline are removed after OEDS, and the content of sulfur from 110 ppm can be reduced to 10 ppm. Moreover, the functionalized heteropoly acid catalyst has showed good recyclability.

Preparation of cis-pinane via α-pinene hydrogenation in water by using Ru nanoparticles immobilized in functionalized amphiphilic mesoporous silica

Amphiphilic mesoporous silica modified with trimethoxy (3,3,3-trifluoropropyl) silane (TFPS) and (3-aminopropyl) trimethoxysilane (APTS) was prepared by one-step synthesis. The structure and morphology of the mesoporous silica were characterized and confirmed by solid-state nuclear magnetic resonance, X-ray diffraction (XRD), N2 adsorption–desorption, Fourier transfer infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Meanwhile, the thermostability of the amphiphilic mesoporous silica was detected by thermogravimetric (TG) technique. Highly dispersed Ru nanoparticles supported on such amphiphilic mesoporous silica (marked as Ru/MF@MN) were synthesized by wet impregnation method with the assistance of ultrasonic. The catalyst was characterized by X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). In water medium, Ru/MF@MN was used in α-pinene hydrogenation to prepare cis-pinane. Under the optimum reaction conditions (35 °C, 2 MPa H2, 1 h, m (H2O) : m (α-pinene) : m (Ru/MF@MN) = 200 : 60 : 1), 99.9% α-pinene conversion and 98.9% cis-pinane selectivity were obtained. When Ru/MF@MN was recycled six times, the conversion slightly decreased and the selectivity was nearly unchanged.

Isobutane/2-butene alkylation catalyzed by Brønsted–Lewis acidic ionic liquids

The alkylation reaction of isobutane with 2-butene to yield C8-alkylates was performed using Bronsted–Lewis acidic ionic liquids (ILs) comprising various metal chlorides (ZnCl2, FeCl2, FeCl3, CuCl2, CuCl, and AlCl3) on the anion. IL 1-(3-sulfonic acid)-propyl-3-methylimidazolium chlorozincinate [HO3S-(CH2)3-mim]Cl-ZnCl2 (x=0.67) exhibited outstanding catalytic performance, which is attributed to the appropriate acidity, the synergistic effect originating from its double acidic sites and the promoting effect of water on the formation and transfer of protons. The Lewis acidic strength of IL played an important role in improving IL catalytic performance. A 100% conversion of 2-butene with 85.8% selectivity for C8-alkylate was obtained under mild reaction conditions. The IL reusability was good because its alkyl sulfonic acid group being tethered covalently, its anion [Zn2Cl5]− inertia to the active hydrogen, and its insolubility in the product. IL [HO3S-(CH2)3-mim]Cl-ZnCl2 had potential applicability in the benzene alkylation reaction with olefins and halohydrocarbons.

Heteropolyacid Bisalt of N-octyl Ethoxylated Octadecylamine: An Efficient and Reusable Catalyst for Carboxylic Acid-Free Hydration of α-Pinene

A series of heteropoly acid bisalts of N-octyl ethoxylated octadecylamine with high acid strength and excellent emulsifying capacity have been prepared via the partial replacement of protons in neat phosphotungstic acid. These ionic liquids exhibit good activity and selectivity in the hydration of α-pinene, even in the absence of a co-catalyst such as chloroacetic acid. The “excellent emulsifying capacity at the reaction temperature and the liquid–liquid separation at room temperature” for the obtained organic heteropolyacid bisalts catalysts enable their easy recovery and reusability, as demonstrated by a six-run recycling test.Graphical Abstract