Ionic Liquids Made with Dimethyl Carbonate: Solvents as well as Boosted Basic Catalysts for the Michael Reaction

Abstract

The fractal dimension of a macromolecular coil is used for the characterization of a polymeric melt structure. It is shown that the kinetics of oxygen consumption is defined by both the chemical constitution of a polymer and its structure. The quantitative analysis of the kinetical curves of the oxygen consumption in the thermooxidative degradation process was carried out in the framework of the fractal approach. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2378–2381, 2003

Upgrade of Biomass-Derived Levulinic Acid via Ru/C-Catalyzed Hydrogenation to γ-Valerolactone in Aqueous–Organic–Ionic Liquids Multiphase Systems

“…Experiments demonstrated that such metal nanoparticles behaved as the active species and they could be easily recovered and recycled. In this case the best operative conditions were so identified: 150°C, 35 [Cl] as the IL phase was based on our previous experience: 34 this ionic liquid was chosen notwithstanding that it was slightly partitioned in the aqueous phase (Table 3), mainly for its affinity with RuCl 3 . The performance of such a "homogeneous-multiphase" system was evaluated as a function of the IL/Cat ratio.…”

“…Under such conditions, the major advantage is the perfect confinement of the catalytic system in the IL phase that allows not only an easy isolation of the product in quantitative yields but also an in situ reuse of catalysts for at least eight recycles with unchanged performances. 35 Monitoring Reaction Progress and Characterization of Catalysts. The conversion and selectivity of hydrogenation reactions of levulinic acid were determined by 1 H NMR on a Varian Unity 400 MHz NMR spectrometer.…”

“…Subsequently, the autoclave was flushed several times with nitrogen to remove air, pressurized to the desired reaction pressure (typically 35 atm H 2 ), and heated IL1 bearing a lipophilic cation was synthesized following a procedure previously described by us. 35 In the first instance a heterogeneous catalyst was considered, and in particular the one of choice for these reactions was identified as Ru/C, based on literature reports. 9,36 In view of obtaining a multiphase system with three separate organic−IL−water (liquid) phases, the organic solvent was at first chosen for its immiscibility with water, coupled with its ability to dissolve the substrate LA and the product GVL.…”

“…With the aim of establishing the optimal composition of the multiphase system, we started by determining the optimal quantity of IL. Accordingly a series of hydrogenation reactions were run at 100°C, at 35 In the presence of the IL, a third liquid phase between the aqueous and hydrocarbon solvents was observed both at the start and at the end of the hydrogenation tests. In this (third) phase, the Ru/C catalyst was always perfectly confined.…”

Methylcarbonate and Bicarbonate Phosphonium Salts as Catalysts for the Nitroaldol (Henry) Reaction

“…24 Starting from 20.8 g of trioctylphosphine (56.1 mmol), 30 mL of DMC, 30 mL of MeOH, and 27.5 g of trioctylmethylphosphonium methylcarbonate (55.8 mmol; 99%) was obtained 1a. Product 1a (3.00 g; 6.09 mmol) was reacted with water (1.00 g; 55.6 mmol) yielding 2.72 g (6.09 mmol; 100%) of 1b.…”