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Ti IV Compounds

Weigh out accurately about 12g of the solid, dissolve In dil. H2S04and make up to 250 cm with the acid. Pipette a 25.0 cm aliquot of the solution into a 250 cm conical flask, add 100 cm of the acid and heat to 70°-80 C and titrate with standardised 0.02M permanganate solution to the first permanent faint pink colour. Repeat and calculate the average the percentage purity of the solid. [Pg.132]

Set up the apparatus shown in Fig.9.1. Dispense the Ti(III) solution into the aspirator A so that it nearly fills it, while H2 (from Kipp s apparatus) displaces air from the system. Fill the burette B completely with the solution by opening e Tap T. Then empty the burette to allow H2 to displace air from the system. Then fill the burette again with the solution by turning the tap. [Pg.132]

Pipette 25.0 cm of standard 0.1 M Fe(IlI) solution together with 25.0 cm dil. sulphuric acid into a 250 cm conical flask provided with a rubber bung with 2 holes to allow a stream of CO2 (from a Kipp s apparatus) to circulate and a middle hole for the tip of the burette B. Run in the Ti(III) solution with constant stirring until the colour of Fe(III) nearly disappears. Then add 10 cm of 10% NH4SCN solution and continue titration until the colour of the Fe/SCN complex just disappears. [Pg.132]

Alternatively deliver 25.0 cm of the Ti(III) solution into the conical flask, while circulating CO2, which is continued throughout the experiment, add 10 cm of 10% NH4SCN solution and titrate with the Fe(III) solution from a burette until a persistent light brown colour appears. [Pg.132]


By analogy with the reaction of soluble Ti(IV) compounds with H2O2 [22], the mechanism by which TS-1 acts as an oxidation catalyst with H2O2 could consist in the interaction of Ti(IV) of the solid with H2O2 to form a surface peroxotita-nate [7]. In a second stage the surface peroxotitanate can perform the oxidation of the oxidizable organic products if these are indicated by Red, we have ... [Pg.350]

It has been pointed out that the product obtained by treating certain samples of ground a-titanium trichloride (particularly those which contain traces of TiCU or other Ti(IV) compounds) with radioactive alkylalu-minum, shows a certain degree of radioactivity also after submitting it to the action of an acid or an alcohol in an attempt to decompose the metal-carbon bonds. Such radioactivity is due to a contaminant, the nature of which depends on the degree of purity and the amount of crude a-titanium trichloride employed. It generally decreases, eventually attaining very low values if the crude a-titanium trichloride is repeatedly washed with anhydrous benzene before its use. [Pg.51]

It is now realised that almost all catalysts based on Ti(III) or Ti(IV) compounds and methylaluminoxane, soluble in aromatic solvents, could polymerise styrene into a highly syndiotactic polymer. The syndiotacticity measured by 13C NMR spectroscopy can be greater than 98%. Syndiospecific polymerisation of styrene with homogeneous catalysts is characterised by a narrow molecular weight distribution (Mw/Mn can reach a value of 2). [Pg.252]

You should look upon silyl enol ethers as rather reactive alkenes that combine with things like protons or bromine (Chapter 21) but do not react with aldehydes and ketones without catalysis they are much less reactive than lithium enolates. As with alkylation (p. 674), a Lewis acid catalyst is needed to get the aldol reaction to work, and a Ti(IV) compound such as TiCl4 is the most popular. [Pg.699]

The electronic configuration of titanium is [Ar] 3d24s2, which means that Ti(IV) compounds are d° species with free coordination sites 1-27,28). H-NMR and 13C-NMR data are known and have been occasionally discussed in terms of bond polarity 19), but such interpretations are obviously of limited value. The electronic structure of methyltitanium trichloride 17 and other reagents have been considered qualitatively 52) and quantitatively S3 56> using molecular orbital procedures. It is problematical to compare these calculations in a quantitative way with those that have been carried out for methyllithium 57> since different methods, basis sets and assumptions are involved, but the extreme polar nature of the C—Li bond does not appear to apply to the C—Ti analog. Several MO calculations of the w-interaction between ethylene and methyltitanium trichloride 17 (models for Ziegler-Natta polymerization) clearly emphasize the role of vacant coordination sites at titanium 58). [Pg.9]

Similarly, EtjAlCl adds to terminal alkenes in the presence of Ti(IV) compounds" ... [Pg.223]

The catalyst is usually a Ti(IV) compound typically 1-3 % of the molar amount of the organomagnesium is used ... [Pg.466]

Terpenoids. In the presence of this Ti(IV) compound as catalyst, isoprene undergoes a regioselective insertion into aUyl—magnesium bonds as exemphfied for the reaction of crotylmagnesium chloride (1) in equation I. Evidently, (1) reacts in the isomeric form (lb). The products (2) can undergo usual Grignard reactions. [Pg.48]

The reactions show high regioselectivity. Details of the mechanism are illustrated in Chapter 1, Scheme 1.32. Ti(IV) compound-catalyzed hydromagnesation of alkenes (Eq. 5.34) by using propyl Grignard reagent involves transmetalation of alkyl group between Mg and Ti compounds (Scheme 5.22) [137,138],... [Pg.257]

There are various Ti(IV) compounds such as phosphates, sulfates, and nitrates as well as various titanates of calcium, iron, and sodium [2]. TiCl4 and the titanates hydrolyze readily to Ti02 Ti(IV) in aqueous solution exists only as hydrated Ti02 species. TiCU is a liquid that is relatively stable in cold water and is used as an intermediate in the production of Ti pigments and in refining Ti metal by reduction of TiCU with Mg. The Ti(III) compound TiCls is a powerful reducing agent useful in synthetic chemistry. [Pg.627]

Reactions of (CpoTiCpp. Reactions representative for (Cp TiCl) are sunnnarized in Scheme 2. Noteworthy are the reactions in which the metal is oxidized e.g. with CO under formation of carbon monoxide, and the disproportionation to Ti(II) and Ti(IV) compounds as was found for L = CO and CS2 which also is eminent in Cp TiR chemistry vide infra). [Pg.201]

In 1959 Bestian et d. 3,23,24) first used a bimetallic catalyst system of the Ziegler-Natta type (TiCl4 or an alkylated Ti(IV) compound in combination with an alkyl aluminumhalide) at extremely low temperatures ( —1(X) to —50°) for the oligomerization of ethylene. [Pg.8]

TiCl with triethylaluminum is one d the cla ic Ziegler-Natta systems for the polymerization ethylene to hi -molecular-weight materiaL However, the soluble Ti(IV) compound is reduced to insoluble TiCls, even at low temperatures, and a heterogeneous Ti/Al sur ce complex is generally assumed to be the active species. [Pg.8]

Ti(IV) compounds are also able to catalyze hydroperoxides decomposition into ketone-alcohol mixtures, a well-known industrial process for acetone and phenol production. [46-48] In particular, a kinetic study reported by Sukin et al. showed that, in titanium(IV) catalysed... [Pg.338]


See other pages where Ti IV Compounds is mentioned: [Pg.446]    [Pg.348]    [Pg.56]    [Pg.315]    [Pg.132]    [Pg.42]    [Pg.3772]    [Pg.304]    [Pg.431]    [Pg.532]    [Pg.654]    [Pg.745]    [Pg.72]    [Pg.475]    [Pg.7]    [Pg.409]    [Pg.228]    [Pg.6]    [Pg.263]    [Pg.131]    [Pg.339]   


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IV) Compounds

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