Surface acetylacetonates

Some porous ceramic structures of oxides on titanium (CT2O3, RuOj, MnOj, VOJ obtained by baking films of metal complexes like acetylacetonates on titanium surfaces can also be regarded as chemically modified electrodes Applications... 

The same behaviour has been found with Cu/ZrOa. A highly dispersed Cu phase was obtained at the surface of zirconla by reacting the support with Cu acetylacetonate [19]. This procedure yields an active catalyst. This catalyst was selective for Na formation at low temperature (< 550 K), but produced only NO2 when the temperature becomes higher than 650 K. However, the same type of catalyst prepared from sulfated zirconia did not produce NO2 but selectively reduces NO to N2 whatever the temperature, with a yield of about 40% at 670 K, and a GHSV of 70000 h l, using only 300 ppm of decane. 

In this paper we report (i) the catalytic activity for SCR of VOx/Zr02 samples prepared by various methods (adsorption from aqueous metavanadate solutions at different pH values, dry impregnation, and adsorption from VO(acetylacetonate)2 in toluene), (ii) sample characterization (nuclearity, dispersion and oxidation state) by means of XPS, ESR and FTIR and (iii) the nature and reactivity of the surface species observed in the presence of the reactant mixture. Catalytic results are here reported in full. Characterization data relevant to the discussion of the catalytic activity will be given, whereas details on the catalysts preparation and... 

The approach comprises deposition-precipitation (DP) of Au(OH)3 onto the hydroxide surfaces of metal oxide supports from an alkaline solution of HAUCI4 [26] and grafting of organo gold complexes such as dimethyl gold (Ill)acetylacetonate (hereafter denoted as Au acac complex) [27] and Au(PPh3)(N03) [28] either in gas and liquid phase are advantageous in that a variety of metal oxides commercially available in the forms of powder, sphere, honeycomb can be used as supports. 

Gas-phase grafting (GG) is characteristic in that gold can be deposited even on the acidic surfaces, such as activated carbon and on Si02 [27]. The vapor of gold acac complex is adsorbed on the support powder probably through the interaction of electron-rich oxygen atoms in acetylacetonate and then calcined in air to decompose it into metallic gold particles. 

CoCl2 was bound to the silica surface using the previous reaction and acetylacetone (AcAcH) (Scheme 7.13).241,242... 

LDHs with Ni/Al molar ratio of 2.5 have been synthesized by a sol-gel method using nickel acetylacetonate and aluminium isopropylate as precursors. The sol-gel synthesized samples exhibited lower crystalhte dimensions and greater BET surface areas compared with coprecipitated samples prepared from an aqueous solution of nickel and aluminium nitrates [19,172]. 

Zirconium Acetylacetonate Sihca supported Zr(lV) acetylacetonate surface complex [(=SiO)3Zr(acac)] (acac = MeCOCHCOMe) catalyzes transesterification reactions [114]. Satisfying silsesquioxane models have been reported [2, 114]. 

Careful stepwise crystallization of cobalt acetylacetonate from solutions of the partially resolved chelate produced surprising results (14). A typical experiment is summarized in Table VI. The molecular rotation of the filtrates steadily increased as each crystal crop was removed until no solute remained in solution— at this time all optical activity had, of course, been lost. All crystal crops were racemic It seems that the racemate is being preferentially crystallized from solution and at the same time a surface racemization is taking place to make up the deficient enantiomorph as the d, l crystals are formed. 

Only a small amount of research has been published dealing with the reactions of / -diketones with clean metal surfaces.513,514 The interaction of acetylacetone with iron and nickel films under ultra high vacuum conditions has been investigated. X-Ray photoelectron spectroscopy is a particularly useful analytical probe as data on gas phase metal acetylacetonates are available for comparison.515 On iron, dissociative adsorption giving acetylacetonate occurs at 90 K. This decomposes at about 290 K to form surface oxide, chemisorbed oxygen and a species considered to contain Fe—C bonds. 

L1. Printing inks. It is now fairly traditional to use titanium acetylacetonate and related species as adhesion promoters in flexographic and gravure printing inks for printing onto plastics such as polyolefins and polyesters which have previously been corona discharge-treated, to oxidize the surface [4]. Zirconium... 

Zirconium acetylacetonate can react in a similar way and as noted previously, surface analysis of zirconium acetylacetonate derivatives on corona-discharged polypropylene has shown bonding to the surface carboxyl groups [6]. 

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