Continuous Gas‐Phase Hydroformylation of 1‐Butene using Supported Ionic Liquid Phase (SILP) Catalysts

The concept of supported ionic liquid phase (SILP) catalysis has been extended to 1‐butene hydroformylation. A rhodium‐sulfoxantphos complex was dissolved in [BMIM][n‐C₈H₁₇OSO₃] and this solution was highly dispersed on silica. Continuous gas‐phase experiments in a fixed‐bed reactor revealed these SILP catalysts to be highly active, selective and long‐term stable. Kinetic data have been acquired by variation of temperature, pressure, syngas composition, substrate and catalyst concentration. A linear dependency in rhodium concentration could be established over a large concentration range giving another excellent hint for truly homogeneous catalysis in the SILP system. Compared to former studies using propene, the SILP system showed significantly higher activity and selectivity with 1‐butene as feedstock. These findings could be elucidated by solubility measurements using a magnetic microbalance.     

Supported ionic liquids: versatile reaction and separation media

The latest developments in supported ionic liquid phase (SILP) systems for catalysis and separation technology are surveyed. The SILP concept combines the advantages of homogeneous catalysis with heterogeneous process technology, and a variety of reactions have been studied where supported ionic liquid catalysts proved to be more active and selective than common systems. In separation applications the use of supported ionic liquids can facilitate selective transport of substrates across membranes.     

Enzyme‐catalyzed regioselective synthesis of sucrose‐based esters

Sucrose‐based esters are nonionic biosurfactants, which can be synthesized from the enzyme‐catalyzed esterification/transesterification of sucrose. The multi‐hydroxyl groups of sucrose and the immiscibility of sucrose with the acyl donors are the main bottlenecks in obtaining highly regioselective sucrose‐based esters. In this mini‐review, the effects of reaction conditions such as biocatalysts, design of solvent systems used as reaction media, modification and denaturation of substrates, and coupling with external auxiliary physical fields such as microwave irradiation and ultrasonic waves on the yield of sucrose esters and regioselectivity of products are highlighted. The existing problems in the field of enzymatic synthesis of sucrose esters as well as its future perspectives were pointed out. Copyright © 2011 Society of Chemical Industry     

Hydroaminomethylation of n‐Alkenes in a Biphasic Ionic Liquid System

Hydroaminomethylation reactions were performed successfully in an imidazolium‐based ionic liquid using a rhodium/sulfoxantphos system by reacting piperidine with different n‐alkenes, affording yields higher than 95 % of the resulting amine with turnover frequencies of up to 16,000 h⁻¹, along with high regioselectivity for the linear amines with l/b ratios up to 78. Additionally, facile quantitative catalyst recovery was accomplished and recycling of the catalyst and product separation was achieved by a fast phase separation after the reaction. The product distribution was monitored over time at different temperatures both in an organic solvent and in the ionic liquid in order to investigate and compare the course of the formation of (side) products and intermediates in these reactions. Furthermore, it was shown that the nature of the rhodium precatalyst has a profound effect on the activity and selectivity. Protic organic solvents and ionic liquids containing a C H acidic bond in the imidazolium part have a beneficial effect on the hydrogenation activity of the catalyst systems.     

Predicting solvent effects on the 1‐dodecene hydroformylation reaction equilibrium

Solvent effects on the reaction equilibrium of the 1‐dodecene hydroformylation in a decane/N,N‐dimethylformamide solvent system is investigated. The reaction was performed at different decane/N,N‐dimethylformamide ratios and at temperatures between 368 K and 388 K. The equilibrium concentrations of all reactants and products were determined experimentally. The enthalpy and Gibbs energy of this reaction at the ideal‐gas standard state were determined by quantum‐chemical calculations in good agreement with literature data. Moreover, quantum‐chemically calculated standard Gibbs energies of reaction at infinite dilution in liquid decane/DMF‐solvent mixtures allowed a qualitative prediction of the solvent effect on the equilibrium concentrations. Based on the standard Gibbs energy of reaction at the ideal‐gas standard state and on fugacity coefficients calculated using the Perturbed‐Chain Statistical Associating Fluid Theory, the equilibrium concentrations of reactants and products for the 1‐dodecene hydroformylation performed in decane/N,N‐dimethylformamide mixtures of different compositions could be predicted in very good agreement with experimental data. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4576–4585, 2017     

咪唑类离子液体的催化加成反应

离子液体作为一种新型绿色溶剂,具有许多独特的物理化学性质,可用在许多重要领域。简单介绍离子液体及其特点,重点介绍在咪唑类离子液体中Diels-Alder,Michael,Bischler-Napieralski等典型的加成反应。     

咪唑类离子液体及其催化C-C偶联反应

离子液体作为一种新型绿色溶剂,具有许多独特的物理化学性质,近年来逐渐被人们所认知,并发现可用在许多重要领域.本文简单介绍离子液体的种类和特点,重点介绍在咪唑类离子液体中的Michael、Heck、Suzuki、Witting、Baylis-Hillman和Aldol等重要的C-C偶联反应.     

Asymmetric Carbon‐Carbon Bond Forming Reactions Catalysed by Metal(II) Bis(oxazoline) Complexes Immobilized using Supported Ionic Liquids

A series of bis(oxazoline) metal(II) complexes has been supported on silica and carbon supports by non‐covalent immobilisation using an ionic liquid. The catalytic performance of these solids was compared for the enantioselective Diels–Alder reaction between N‐acryloyloxazolidinone and cyclopentadiene and the Mukaiyama‐aldol reaction between methyl pyruvate and 1‐methoxy‐1‐trimethylsilyloxypropene. In both reactions the enantioselectivity was strongly influenced by the choice of support displaying enantioselectivies (ee values) up to 40% higher than those conducted under homogeneous reaction conditions.     

Support‐dependent activity of noble metal substituted oxide catalysts for the water gas shift reaction

The water gas shift reaction was carried out over noble metal ion substituted nanocrystalline oxide catalysts with different supports. Spectroscopic studies of the catalysts before and after the reaction showed different surface phenomena occurring over the catalysts. Reaction mechanisms were proposed based upon the surface processes and intermediates formed. The dual site mechanism utilizing the oxide ion vacancies for water dissociation and metal ions for CO adsorption was proposed to describe the kinetics of the reaction over the reducible oxides like CeO₂. A mechanism based on the interaction of adsorbed CO and the hydroxyl group was proposed for the reaction over ZrO₂. A hybrid mechanism based on oxide ion vacancies and surface hydroxyl groups was proposed for the reaction over TiO₂. The deactivation of the catalysts was also found to be support dependent. Kinetic models for both activation and deactivation were proposed. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

Immobilization of MacMillan Imidazolidinone as Mac‐SILC and its Catalytic Performance on Sustainable Enantioselective Diels–Alder Cycloaddition

MacMillan’s imidazolidinone catalyst was immobilized as a supported ionic liquid catalyst (Mac‐SILC) in the pores of silica gel with the aid of an ionic liquid – 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide. The heterogenized organocatalyst was utilized for the enantioselective Diels–Alder reaction of cyclopentadiene and cinnamaldehyde, recovered by simple filtration and subsequent evacuation, and repeatedly used up to six times in 81% average chemical yield, 87% ee for endo‐ and 80% ee for exo‐products. The Mac‐SILC was effective for a variety of substrates.     

Improved Stability and Catalytic Activity of Palladium Nanoparticle Catalysts using Phosphine‐Functionalized Imidazolium Ionic Liquids

Palladium nanoparticles (Pd NPs) stabilized by 6 different phosphine‐functionalized ionic liquids (PFILs) were synthesized in imidazolium‐based ionic liquids (ILs) using H_2(g) (4 bar) as a reductant. Characterization showed well‐dispersed particles of ∼3 nm (TEM) and confirmed the PFIL stabilization of the NPs (XPS). The PFILs were composed of an imidazolium functionality separated from the phosphine group by a propyl or undecyl chain. The counter anions for both FILs and IL solvents were chosen from N‐bis(trifluoromethanesulfonyl)imide (Tf₂N⁻), trifluoromethanesulfonate (TfO⁻) or hexafluorophosphate (PF₆⁻). Colloidal suspensions of the Pd NPs were employed as biphasic hydrogenation catalysts for the reduction of the olefinic bond in styrene under mild conditions (50 °C, 4 bar H_2(g), 1.5 h). The PFIL‐stabilized Pd NPs were effective hydrogenation catalysts and showed superior activity and recyclability over NPs synthesized in the absence of PFILs. Poisoning tests of the Pd NP catalysts and characterization of the electronic properties of the phosphine were also performed.     

Proline‐Catalyzed Asymmetric Aldol Reaction in Guanidine‐ Derived Ionic Liquids

A remarkable improvement of both the chemical yield (from 6% to 82%) and the enantiomeric excess (up to >99%), of (S)‐proline catalyzed direct aldol reactions of a wide range of aldehydes with acetone was found when hexasubstituted or pentasubstituted guanidinium salts were added as ionic liquids. Effects of temperature, amount of proline and the type of guandidinium salts on the outcome of the reaction were investigated.     

Ionic Liquid‐Promoted Oxidant‐Free Dehydrogenation of Alcohols with Water‐Soluble Ruthenium Nanoparticles in Aqueous Phase

An oxidant‐free dehydrogenation of alcohols in the aqueous phase was developed for the first time using water‐soluble poly(N‐vinyl‐2‐pyrrolidone) (PVP)‐stabilized ruthenium nanoparticles with an ionic liquid as a promoter. The present catalytic system was highly efficient and stable for the catalytic dehydrogenation of various alcohols. It was found that the basic ionic liquid 1‐n‐butyl‐2,3‐dimethylimidazolium acetate ([BMMIM] OAc) additive played a crucial role in enhancing the catalytic activity and stability of ruthenium(0) nanoparticles. A reaction kinetics study and ¹H NMR analysis demonstrated that the basic ionic liquid and ruthenium nanoparticles exerted a synergetic effect for the dehydrogenation reaction.     

The Use of Porous Palladium(II)‐polyimine in Cooperatively‐ catalyzed Highly Enantioselective Cascade Transformations

Porous organic polymers have prospects as functional substrates for catalysis, with quite different molecular properties from inorganic substrates. Here we disclose for the first time that porous palladium(II)‐polyimines are excellent catalysts for cooperatively catalyzed and enantioselective cascade reactions. In synergy with a chiral amine co‐catalyst, polysubstituted cyclopentenes and spirocyclic oxindoles, including the all‐carbon quaternary stereocenter, were synthesized in high yields. High diastereo‐ and enantioselectivities were achieved for these dynamic kinetic asymmetric transformations (DYKAT) of enals with propargylic nucleophiles.

     

离子液体在两相催化中的研究进展和应用前景

介绍了近年来离子液体用于液液两相催化加氢、氧化、Heck反应、氢酯化和羰化反应的研究进展,特别是结合离子液体在高碳烯烃氢甲酰化和低碳烯烃齐聚中试成果和已经实现工业应用的实例,从绿色化工的角度对其在化学工业中的应用前景进行了评述。     

羰基合成反应催化剂新配体和负载水相催化剂的研制及应用

国家科技部“九五”攻关项目“羰基合成(烯烃氢甲酰化反应)负载水相催化剂的创制”专题在攻关过程中创制了5套完整的新技术、新工艺和新物种,可经过中试,推进产业化。研究过程中在分子设计思想的指导下,预测了1-苯基二苯并膦(简称PDBP)是一个极好的羰基合成新配体,并成功合成出PDBP,将其磺化可制得PDBPDS二磺化产物。同时创制了负载水相催化剂制备工艺,并对均相、两相和多相氢甲酰化反应中催化性能进行了考察。结果表明新型配体PDBP在羰基合成反应中在选择性和活性方面都优于三苯基膦,负载水相催化剂集中了均相反应和多相反应的优势,不但活性高、选择性好,而且有效地解决了铑流失的技术难题,证明了新配体和负载水相催化剂是极具开发前景的物种和催化剂。