Barium isopropoxide

Hydrolysis of metal-organic solutions Example. Ba(OC3H7)2 + Ti(OC5Hu)4 + H2O — BaTiOs (Barium isopropoxide and Titanium tertiary amyloxide are refluxed in isopropanol and then hydrolyzed with de-ionized water to produce a sol-gel. ... 

Aldol reactions. The complex, prepared from barium isopropoxide and (/ )-BINOL methyl ether in DME at room temperature, promotes asymmetric aldol reactions (7 examples, 77-99% yield, 50-70% ee). 

Usually, preparation of alkoxide precursor includes dissolving of pure metallic barium or strontium in isopropanol to obtain barium isopropoxide Ba((X 3H7)2 [189,190]. Titanium isopropoxide Ti (OC3H7)4 obtained from tetrachloride, TCU ... 

Several groups exploited the power of the intermolecular Diels-Alder reaction early in their syntheses for the formation of substituted cyclohexenes. In his synthesis of platencin, Nicolaou used a Danishefsky-like diene in an asymmetric Diels-Alder reaction for the synthesis of a chiral cylohexenone. Kanai and Shibasaki developed a catalytic asymmetric Diels-Alder reaction promoted by barium isopropoxide for the first step in their synthesis of Tamiflu. Danishefsky constructed the cyclohexene ring in paecilomycine A by employing a highly e t/o-selective Diels-Alder reaction of siloxydiene 115 and enyne dienophile 116 to yield target 117. ... 

Methylethylketone (5 g) solutions of the polymer (10 wt%) was added to isopropanol (0.2732 g) solutions of titanium isopropoxide (0.106 g, 0.3687 mmol) and barium bis-isopropoxide (0.367 g, 0.3687 mmol) the solution was cast onto microscope slides. The polymer film was dried, removed, and hydrolyzed in boiling barium hydroxide solution... 

OXIDATION, REAGENTS Barium mangan-ate. Benzyl(triethyl)ammonium permanganate. Bispyridinesilver permanganate. Bis(trimethylsilyl)peroxide. t-Butyl hydroperoxide. t-Butyl hydroperoxide-Benzyltri-methylammonium tetrabromooxomolyb-dale. t-Butyl hydroperoxide-Bisoxobis-(2,4-pentadionato)molybdenum. t-Butyl hydroperoxide-Chromium carbonyl. t-Bu-tyl hydroperoxide-Dialkyl tartrate-Titan-ium(IV) isopropoxide. t-Butyl hydroper-... 

Figure 35 (a) Molecular structure of Ba-Ti oxo-alkoxide, reproduced with permission from the Royal Society of Chemistry, (b) Comparison of the core structure of monoclinic barium-titanium oxo-isopropoxide with the BaTiOs structure viewed along the [111] direction, reproduced with permission from Wiley. ... 

The barium bis-isopropoxide was prepared by the metal/alcohol reaction method. Appropriate amounts of these alkoxides were dissolved in a mutual solvent, such as isopropyl alcohol or benzene, for a barium and titanium molar ratio of 1 1. The solution was refluxed for 2 h with vigorous stirring before the hydrolysis reaction. Drops of deionized triply distilled water were slowly added to the solution, which was continuously stirred. The reaction was carried out in a C02-free atmosphere. The hydrated oxide was dried in vacuum or in a dry helium atmosphere at 50°C for 12 h. At this stage the oxide was a finely divided, stoichiometric titanate with 50-150 A (maximum agglomerate size <1 pm) particles and was more than 99.98% pure. TEM photomicrographs of the as-prepared and the calcined (700°C for 1 h) powders are shown in Fig. 8. The rectilinear symmetry of the particles is evident in the calcined powders. 

Phule, D. P., and Risbud, S. H., Sol-gel synthesis of barium titanate powders using barium acetate and titanium(IV) isopropoxide, Adv. Ceram. Mat., 3, 183 (1988). 

To increase the mixing effects and interaction with the hydroxyl groups, the PEG polymer may be replaced by its monomer, ethylene glycol (EG, 0H(CH2)0H). The EG method also has the advantage of the use of alcohol soluble source chemical such as titanium isopropoxide. Nano-sized titania, calcium titanate [17,18] and barium titanate [9] have been synthesized by the EG method at relatively low organic weight percentages. 

BaTiOs Titanium isopropoxide, barium acetate Glacial acetic acid, ethylene glycol 4... 

A detailed sol-emulsion-gel process was developed by Chatterjee etal. [195] for the synthesis of barium titanate, BaTi03. Three varieties of sols were prepared as the aqueous phase while titanium isopropoxide (Ti(0 Pr)4) remained the source... 

BaTi03 Barium acetate + titanium isopropoxide Ethanol Acetic acid PVP Yuh et al. (2005)... 

Formation of different complexes at different ratios of reactants in the same solvent (THF in this case) can be illustrated by the examples from barium-zirconium isopropoxide system (Vaartstra, 1991) (the authors used barium metal in the presence of solvating alcohol, but application of the ready alkoxide gives the same result (Turevskaya, 1995)) ... 

Kuhlman R., Vaarstra B.A., Streib W.E., Huffman J.C., Caulton K.G. Primary steps in the hydrolyses of two heterometallic alkoxides. Characterization of lithium-titanium and barium-zirconium isopropoxides [LiTiO(0-wo-Pr)3]4 and BaZr4(OH)(O-W0-Pr)i7. Inorg. Chem. 1993 32 ... 

Dissolution of barium ethoxide and titanium isopropoxide in a mixed solvent comprising dehydrated methanol (60 vol%) and 2-methoxyethanol (40 vol%) to form a Ba,Ti-alkoxide precursor. 

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