Titanium ethoxides synthesis

One approach to making such powders is the sol-gel method, in which a metal oxide powder is synthesized from a metal alkoxide, a compound derived from a metal and an alcohol. In the synthesis of titania (Ti02) from titanium ethoxide, Ti(OCH2CH3)4, for example, the Ti(OCH2CH3)4 starting material is made by the reaction of titanium(IV) chloride with ethanol and ammonia in a benzene solution ... 

A particularly effective method for the asymmetric synthesis of both aldehyde-and ketone-derived sulfinimines recently introduced by Davis and co-workers is the condensation of (5)-(+)-p-toluenesulfinamide (63) with aldehydes and ketones using activated 4-A molecular sieves or titanium ethoxide [Ti(OEt)4].46 This procedure avoids the problem of removing the menthol by-product of the one-pot procedure (see Section II.D) which is sometimes problematic.23 Importantly, this methodology affords ketone derived sulfinimines 66 which are difficult to prepare by other means. 

J. Valverde, P. Sanchez, F. Dorado, C. Molina, and A. Romero, Influence of the Synthesis Conditions on the Preparation of Titanium-pillared Clays Using Hydrolyzed Titanium Ethoxide as the Pillared Agent. Microporous Mesoporous Mater., 2002, 54, 155-165. 

The solubility factor has been found to be of some use for the synthesis of insoluble alkoxides. For example, when titanium ethoxide or isopropoxide is treated with methanol, an instantaneous reaction occurs with the separation of insoluble methoxide. The fractionation process is not necessary in cases where such insoluble derivatives are obtained. 

Taramasso et al. (5) had originally reported two methods for the hydrothermal synthesis of TS-1. The first method (mixed alkoxide method) involves the preparation of a solution of mixed alkoxides of titanium and silica (preferably ethoxides) followed by hydrolysis with alkali-free solution of tetrapropylammonium hydroxide (TPAOH), distillation of the alcohol and crystallization of the resulting gel at 448 K. In the second method (dissolved or hydrolyzed titanium method) a soluble tetrapropylammonium peroxo-titanate species was prepared initially and then colloidal SiC>2 (Ludox AS-40) was added. This entire operation had to be carried out at 278 K. The TS-1 samples obtained by these two synthesis routes differed, particularly because of the presence of impurities such as Al3+ usually present in colloidal silica (33). 

The direct electrochemical synthesis of metal alkoxides by the anodic dissolution of metals into alcohols containing conducting electrolytes was initially demonstrated by Szilard in 1906 for the methoxides of copper and lead.19 More recently the method has received some attention particularly in the patent literature.29-25 The preparation of the ethoxides of silicon, titanium, germanium, zirconium and tantalum by electrolysis of ethanolic solutions of NH Cl has been patented, although the production of the ethoxides was found to cease after several hours.24,25... 

The metal salts of alcohols are called alkoxides, M(OR), where M is a metal and R is an alkyl group. Typical examples in the synthesis of ferroelectric thin films include titanium isopropoxide [Ti(OPr )4 where Pr represents isopropyl], tantalum ethoxide [Ta(OEt)5 where Et represents ethyl], and zirconium butoxide butanol [Zr(OBu )4 n-BuOH where Bu represents -butyl], an alkoxide/alcohol compound. The structure of this compound, shown in Figure 27.3a, illustrates its dimeric nature, that is, the fact that each molecule contains two metal centers. 

Laser-activated pyrolysis has been applied for the synthesis of ultrafine Ti02 with titanium isopropoxide or ethoxide as precursors [33]. A specific surface area of 128m g was obtained. 

The reaction of titanium phenolates, derived from phenols and titanium(IV) ethoxide, with p-phenylcimiamaldehydes 8 (R = Ph) <79JOC803> can be successful where other strategies fail. The extra effort involved in the synthesis of the cirmamaldehyde, of which relatively few structurally diverse aryl substituted examples are readily available, may be justified, as for example in their reaction with electron-deficient hydroxy-substituted heteroeycles (Scheme 4) <97HCA725>. 

Mosset A., Galy J. Synthesis and structural study of the entity titanium oxide ethoxide (Tii60i6-(0C2H5)32) An example of intramolecular twinning. Comp. Rend., Ser. 2. 1988 307 1747 Nabavi M., Sanchez C., Livage J. Sol-gel synthesis of vanadium oxide from alkoxides. Eur. J. Solid State Inorg. Chem. 1991 28 1173... 

Chromenes.- Continuing interest in the precocenes and their biological action has stimulated further work on their synthesis. Precocene III (82) has been synthesized from a phenol, 3-methylbut-2-enal and titanium(lV) ethoxide and precocenes I and II were obtained by cyclization of the relevant 3-methoxyphenol with isoprene and dehydrogenating the resultant chroman with DDQ. Several new positional isomers of precocenes and related compounds have been synthesized and screened for insecticidal activity in a rice crop. Chromanones [such as (83)] were reduced with LAH to the chromanol which was efficiently dehydrated with a trace of toluene-4-sulphonic acid. Under some conditions, reduction gave dimeric... 

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