Search results for "titanium"
showing 10 items of 878 documents
Synthesis and catalytic studies of Ti-anchored disilanol isobutyl-POSS/alkylaluminum system
2012
Abstract Titanium (IV) precursors anchored to alkyl substituted polyhedral oligomeric silsesquioxane (POSS) disilanol were prepared and characterized. These catalysts formulated as [Ti(O^O)2] and [M(O^O)XCl] are found to be active in polymerization of ethylene at high temperatures in combination with ethylaluminum sesquichloride (Et3Al2Cl3) as co-catalyst. The polyethylene product so obtained is linear, crystalline and displays narrow dispersities. The unique low molecular weight PE formed in this reaction exhibit properties that have potential industrial applications. The effect of various reaction parameters on catalyst performance is described.
Photocatalytic degradation of 4-nitrophenol in aqueous suspension by using polycrystalline TiO2 impregnated with functionalised Cu(II)-porphyrin or C…
2003
The photocatalytic activity of polycrystalline TiO2 samples impregnated with functionalized Cu(II)- or metal-free porphyrins has been investigated. A probe reaction, i.e., 4-nitrophenol (4-NP) photodegradation in aqueous suspension, has been used. The results indicated that the presence of the sensitizers is beneficial for the photoactivity and suggest an important role of Cu(II). A comparison with similar samples impregnated with modified Cu(II)- and metal-free phthalocyanines showed that the presence of porphyrin is more beneficial both for the decomposition rate of 4-nitrophenol and for the disappearance of nonpurgeable organic carbon (NPOC). Experiments were carried out by using cutoff …
Tailoring the ligand structure to the reagent in the mandelamide-Ti(IV) catalyzed enantioselective addition of dimethyl- and diethylzinc to aldehydes
2007
Amides derived from (S)-(+)-mandelic acid in the presence of titanium isopropoxide catalyze the enantioselective addition of dimethyl- and diethylzinc to aldehydes with good yields and ee up to 90%. Because of the modular character of the mandelamides, the structure of the ligand can be tailored to obtain the best results with each reagent. Thus, best results with dimethylzinc are obtained with N-benzyl mandelamide while N-(pyridin-2-yl) mandelamide is the best ligand for the addition of diethylzinc.
Linked Benzylamido-Cyclopentadienyl Ligands: Synthesis and Characterization of Alkyl Titanium Complexes
1997
Titanium complexes of the general type Ti(η5:η1-C5H4Si-Me2NCH2C6H3X2-2,5)Cl2 (XH, F), containing a linked benzylamido-cyclopentadienyl ligand, were prepared by reaction of Ti(η5-C5H4SiMe2Cl)Cl3 with lithium amide Li(NHCH2C6H3X2-2,5). A single-crystal X-ray structural analysis of Ti(η5: η1-C5H4SiME2NCH2C6H3F2-2,5)Cl2 revealed a conformation in the solid state in which the aryl ring is turned away from the metal center. Ti(η5:η1-C5H4SiMe2NCH2C6H5)Cl2 can be alkylated with a variety of reagents to form extremely sensitive complexes of the type Ti(η5-C5H4SiMe,2NCH2C6H5)R2 (RMe, CH2 C6H5, CH2SiME3, CH2CMe2C6H5). Reaction of Li2[C5Me4SiMe2NCH2C6H5] with TiCl3(THF)3 gave Ti(η5: η1-C5Me4SiMe2NCH2C6…
Biologizing titanium alloy implant material with morphogenetically active polyphosphate
2015
As a further step towards a new generation of bone implant materials, we developed a procedure for biological functionalization of titanium alloy surfaces with inorganic calcium polyphosphate (Ca-polyP). This polymer has been demonstrated to exhibit morphogenetic activity. The coating of titanium oxidized Ti-6Al-4V scaffolds with biologically active amorphous Ca-polyP microparticles is formed by Ca2+ ion bridges to the silane coupling agent APTMS. This surface is durable and stable as an almost homogeneous Ca-polyP layer onto the metal. The homogenously coated Ca-polyP titanium scaffold was found to be biologically active and supported the growth and functional activity of bone cell-related…
Superhydrophobic TiO2/Fluorinated Polysiloxane Hybrid Coatings with Controlled Morphology for Solar Photocatalysis
2021
Abstract Technological applications of polysiloxane coatings have been influenced by their intrinsic low surface energy, which increases their water repellence. Accurate control of composition and interfacial properties through the introduction of perfluorinated moieties further lowers the polysiloxane surface energy, while mixing with metal oxide nanoparticles enhances roughness, resulting in a great potential in the development of superhydrophobic materials for photocatalysis. Herein, a series of hydrophobic and superhydrophobic hybrid coatings were prepared by dehydrocoupling and hydrosilylation reactions of polymethylhydrosiloxane with 1H,1H,2H,2H‐perfluorooctyltriethoxysilane and 1,3-d…
Production of titanium ion beams in an ECR ion source
2002
Abstract Intensive highly charged Ti ion beams were successfully produced in the 14 GHz ECR ion source at the Accelerator Laboratory, University of Jyvaskyla (JYFL). The Ti beams were produced using the MIVOC technique, i.e. by allowing the vapor of an organic compound containing titanium to diffuse into the ion source at room temperature. After optimizing the source parameters the intensity of the 48 Ti 11+ ion beam reached a value of 45 μA.
Synthesis of all-syn Functionalized Triphenylene Ketals
2011
The stereoselective synthesis of triphenylene ketals offers access to unique scaffolds. For a good performance in supramolecular applications an all-syn orientation of the functional groups is essential. The oxidative trimerization of catechol ketals by molybdenum pentachloride or mixtures with titanium tetrachloride leads to a template-directed formation. Several heterocyclic moieties are suitable for this transformation. A template-directed isomerization of anti,anti,syn isomers to the desired C 3 -symmetric derivative was demonstrated in two cases.
Photoelectrocatalytic selective oxidation of 4-methoxybenzyl alcohol in water by TiO2 supported on titanium anodes
2013
The photoelectrocatalytic partial oxidation of 4-methoxybenzyl alcohol in aqueous solution irradiated by near-UV light was carried out in a three-electrode batch reactor. TiO2 films were either deposited by dip-coating of a TiO2 sol onto a Ti foil and subsequent calcination or generated on Ti plates by thermal oxidation in air at 400-700 degrees C. The effects of the anode preparation method and bias potential values on conversion and selectivity to the corresponding aldehyde were investigated. The photoelectrocatalytic results were compared with the photocatalytic and electrocatalytic ones. The results indicated that no reaction occurred during the electrocatalytic experiments, whereas the…
Photocatalytic Selective Oxidation of 4-Methoxybenzyl Alcohol to Aldehyde in Aqueous Suspension of Home-Prepared Titanium Dioxide Catalyst
2007
WOS: 000246040000026