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Liquid precursor, novel

The Mizoroki-Heck reaction in liquid imidazolium salts as the solvent is a special case of an in situ system Under the reaction conditions NHC complexes of palladium are formed as the active catalyst from the solvent and the ligand-free palladium precursor. In general, ionic liquids are novel reaction media for homogeneous catalysis. They allow easy separation of product and catalyst after the reaction. ... [Pg.46]

In a novel application of supercritical COj, Charpentier et td. [366] prepared bionanocomposites of PVAc and SiOj nanopartides using a one-pot synthesis in supercritical COj wherein all raw chemicals, tetraethoxysilane (TEOS)/tetramethoxysilane (TMOS), vinyltrimethoxysilane (VTMO), vinyl acetate, initiator, and hydrolysis agent were introduced into one autoclave. They found that PVAc nanocomposites with well-dispersed SiOj nanopartides of 10-50 nm were formed opening new opportunities such as the production of metal-oxide-polymer nanocomposites from liquid precursors. [Pg.418]

Among various methods to synthesize nanometer-sized particles [1-3], the liquid-phase reduction method as the novel synthesis method of metallic nanoparticles is one of the easiest procedures, since nanoparticles can be directly obtained from various precursor compounds soluble in a solvent [4], It has been reported that the synthesis of Ni nanoparticles with a diameter from 5 to lOnm and an amorphous-like structure by using this method and the promotion effect of Zn addition to Ni nanoparticles on the catalytic activity for 1-octene hydrogenation [4]. However, unsupported particles were found rather unstable because of its high surface activity to cause tremendous aggregation [5]. In order to solve this problem, their selective deposition onto support particles, such as metal oxides, has been investigated, and also their catalytic activities have been studied. [Pg.391]

The synthesis of nanostructured carbon using aliphatic alcohols as selfassembling molecules has demonstrated that this strategy can be extended beyond metal oxide-based materials [38]. Recently, we have reported the synthesis of a novel carbon material with tunable porosity by using a liquid-crystalline precursor containing a surfactant and a carbon-yielding chemical, furfuryl alcohol. The carbonization of the cured self-assembled carbon precursor produces a new carbon material with both controlled porosity and electrical conductivity. The unique combination of both features is advantageous for many relevant applications. For example, when tested as a supercapacitor electrode, specific capacitances over 120 F/g were obtained without the need to use binders, additives, or activation to increase surface area [38]. The proposed synthesis method is versatile and economically attractive, and allows for the precise control of the structure. [Pg.56]

The polyaromatic mesophase (PA-MP) is a nematic, discotic, chemotropic liquid crystal. Owing to its high density (about 1.5 gcm ), its high carbon yield of about 90 %, and its thermoplasticity, it is unique as a precursor of structure carbons. An important application is the manufacture of high modulus (HM) and ultra-high modulus (UHM) carbon fibers [1]. By alloying with silicon, physical and chemical properties of the materials, such as strength, hardness and oxidation resistance, can be improved. These modified carbons were available by chemical vapor deposition (CVD) processes only up to now. The preparation by liquid phase pyrolysis is novel, economic, and thus opens a completely new field of applications. [Pg.632]

In response to these concerns, and particularly the ones associated with tire nonabsorbable cyanoacrylates that are used clinically. Linden and Shalaby disclosed a novel, absorbable tissue adhesive composition that addressed, to a practical extent, the drawbacks of the absorbable bioadhesive as well as nonabsorbable cyanoacrylates. In effect, these absorbable tissue adhesive compositions were based (1) primarily on methoxyalkyl cyanoacrylates and preferably methoxypropyl cyanoacrylate as the precursor of an absorbable tissue adhesive polymer and (2) on a polymeric, highly absorbable, liquid comprising an oxalate ester of triethylene glycol as a modifier to modulate the viscosity of the overall composition, lower the heat of polymerization, and increase the compliance and absorption rate of the cured adhesive joint. In a more recent disclosure by Shalaby, a number of other useful modifiers were described and the functional performance of the new adhesive compositions was reported. ... [Pg.61]


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See also in sourсe #XX -- [ Pg.132 ]




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Liquid precursors

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