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The α-diimine late transition metal catalyst represents a new strategy for the synthesis of atactic polypropylene elastomer. Taking into account the properties of the material, enhancing the molecular weight of polypropylene at an elevated temperature through modifying the catalyst structure, and further increasing the activity of α-diimine catalyst for propylene polymerization, are urgent problems to be solved. In this work, two α-diimine nickel(II) catalysts with multiple hydroxymethyl phenyl substituents were synthesized and used for propylene homopolymerization. The maximum catalytic activity was 5.40 × 105 gPP/molNi·h, and the activity was still maintained above 105 gPP/molNi·h at 50 °C. The large steric hindrance of catalysts inhibited the chain-walking and chain-transfer reactions, resulting in polypropylene with high molecular weights (407~1101 kg/mol) and low 1,3-enchainment content (3.57~16.96%) in toluene. The low tensile strength (0.3~1.0 MPa), high elongation at break (218~403%) and strain recovery properties (S.R. ~50%, 10 tension cycles) of the resulting polypropylenes, as well as the visible light transmittance of approximately 90%, indicate the characteristics of the transparent elastomer. [ABSTRACT FROM AUTHOR]

The use of CO2 as a CO surrogate for the carbonylation of olefin has attracted considerable attention due to its abundance, readily availability, nontoxicity, and recyclability. In this work, we describe the synthesis of methyl propionate (MPA), a key intermediate for methyl methacrylate in the commercial Lucite Alpha process, by the ruthenium-catalyzed methoxycarbonylation of ethylene with CO2 as a carbonyl source. An efficient approach to producing MPA has been developed by adding metal halide promoters and dehydrating agents. Control experiments suggest that the NHC-Ru-hydride may be the real active species formed in situ by the reaction of Ru3(CO)12 with ionic liquid (IL). NMR data demonstrate that inorganic salts favor the formation of active species, which is an important issue for their promotion effect. In terms of the strategy to overcome chemical equilibrium by the addition of dehydrating agents and IL participation in the formation of NHC-Ru-hydride active species, a tasked IL containing a siloxyl group was employed to Ru-catalyze the methoxycarbonylation of ethylene, which showed higher catalytic efficiency in comparison to IL without a siloxyl group. [ABSTRACT FROM AUTHOR]

A versatile method for the modification of three-dimensionally ordered macroporous (3DOM) highly syndiotactic polystyrene via chloromethylation at the pore walls has been demonstrated. This was followed by reaction with dimethylamine to establish a versatile approach to functionalization of such macroporous polymers. High syndiotacticity of 3DOM sPS is necessary for maintenance of the morphology of the original ordered pore structure after chloromethylation. The relative content of chloromethyl groups was shown to be 1.89 mmol/g3DOM sPS by TG-titration. The functionalized 3DOM sPS was characterized by SEM, FT-IR, and DSC to demonstrate that chloromethylation had occurred at the pore walls and that the dimethylamino moiety had replaced the chlorine atom of the chloromethyl group. DSC examination of the modified polymer indicated that the crystallinity of 3DOM sPS is little affected by functionalization. Thus the excellent properties of sPS are retained by the functionalized material. POLYM. ENG. SCI., 49:223-228, 2009. ©2008 Society of Plastics Engineers, INTRODUCTION Three-dimensionally ordered macroporous (3DOM) materials, ranging from metals, metal oxides, carbon, and silica to polymer (1-5), have attracted increasing attention due to their rich potential in a variety of [...]

Abstract: Highly cross-linked porous poly(N-vinylimidazole-co-divinylbenzene) (PVIm) beads of various pore sizes and specific surface areas were synthesized by suspension polymerization. The surfaces of the PVIm beads were then modified with various alkyl halides to obtain various ionic liquid-grafted porous polymer beads (PVIm-RX), which were then used as heterogeneous catalysts in the synthesis of cyclic carbonate from CO2 and epoxide. All catalytic reactions are carried out under mild conditions (90–130°C, 0.86–2.17MPa) in the absence of organic solvents. The effects of texture properties of the PVIm matrix, molecular compositions of the ionic liquid moieties, and catalytic reaction parameters (reaction temperature, pressure, and time) on the catalytic reactivity of cycloaddition reactions were systematically investigated. The results demonstrate that grafted ionic liquids with more nucleophilic anions, bulkier alkyl chains, or hydroxyl groups improve reactivity. Additionally, the incorporation of small amount of ethanol or water into the reaction system could significantly increase reactivity. In addition, textural properties of the polymer matrix (pore size and specific surface area) affected the catalytic reactions. The obtained PVIm-RX heterogeneous catalysts exhibited higher turnover number than those reported for ionic liquids grafted onto porous silica. [Copyright &y& Elsevier]