Tetrabutylammonium silicate

The studies on tetrabutylammonium silicate (TBAS) aqueous solution. 

D. Hoebbel, A. Vargha, G. Engelhardt, and K. Ujszaszy, On the Anion Constitutions of Tetrabutylammonium Silicates and Their Aqueous Solutions. Z. Anorg. Allg. Chem., 1984, 509, 85-94. 

A new crystalline highly acid tetrabutylammonium silicate (1) and several of its derivatives have been synthesized from aqueous solutions. (1) is face-centered cubic with a 28.605(6), f(exp) = 1.448(5)... 

Hoebbel, D., Vargha, A., Engelhardt, G., and Ujszasky, K. (1984) On the Anion Constitution of Tetrabutylammonium Silicates and their Aqueous Solutions, Z Anorg. Allg. C/rewie, 509,85-94. 

Anilines are converted into nitrosoarenes ArNO by the action of hydrogen peroxide in the presence of [Mo(0)(02)2(H20) (HMPA)]224, whereas catalysis of the reaction by titanium silicate and zeolites results in the formation of azoxybenzenes ArN (0)=NAr225. Azo compounds ArN=NAr are formed in 42-99% yields by the phase-transfer assisted potassium permanganate oxidation of primary aromatic amines in aqueous benzene containing a little tetrabutylammonium bromide226. The reaction of arylamines with chromyl chloride gives solid adducts which, on hydrolysis, yield mixtures of azo compounds, p-benzoquinone and p-benzoquinone anils 234227. 

TASF tris(diethylamino)sulfonium difluoro(trimethyl)silicate TBAF tetrabutylammonium fluoride Tf trifluoromethanesulfonyl THF tetrahydrofuran tol tolyl... 

Figure 3. Specific activity of glucose oxidase intercalated in a smectite layered silicate versus time of aging at 20°C. Loading is 20 g of enzyme/g of silicate. The dashed line shows the specific activity in the presence of tetrabutylammonium ion.

Tetrabutylammonium Hydrogen Silicate Synthesis, Chemical, Thermal, and Crystallographic Properties... 

Tetrabutylaramonium hydrogen silicate hydrate has been synthesized from aqueous solutions of tetraalkylorthosilicates and tetrabutylammonium hydroxide. In a typical experiment Si(OCH ) ... 

Figure 1. Single crystals of tetrabutylammonium hydrogen silicate hydrate.

Table I. X-ray powder diffraction data of tetrabutylammonium hydrogen silicate hydrate (CuK, = 1.5418X).

Figure 3, Titration curve for tetrabutylammonium hydrogen silicate hydrate in aqueous suspension. Key , SiOSi + H O SiOH + HOSi (g SiO + H SiOH , SiOH + OH SiO + and , SiOSi + OH SiO + H05/.

Figure 4, Thermal decomposition of tetrabutylammonium hydrogen silicate hydrate studied by TGA and DSC, Theoretical weight losses for the individual steps of decomposition calculated from the structural formula (2) of the sample are indicated at the left side of the diagram.

Figure 6, Thermal decomposition of two varieties of tetrabutylammonium hydro-gen silicate studied by DSC, Key HtN(CH CHt free phase (the...

TADDOL a,a,a, a -tetraaryl-4,5-dimethoxy-1,3 -dioxolane TASF, Tris-(Diethylamino)sulfonium difluorotrimethyl silicate TBAF, Tetrabutylammonium fluoride TBDMS, tert-Butyldimethylsilyl TBS = TBDMS t-Bu, Bu, tert-Bu, Tertiary butyl TCPP, Tris(p-chlorophenyl)phosphine TDMPP, Tris(2,6-dimethoxyphenyl) phosphine... 

Pentacoordinated silicate TASF, one of the best activators of organosilicon compounds in the Pd-catalyzed cross-coupUng reaction as we have seen, is found to be involved in the coupling reaction with aryl hahdes in the absence of other organosilanes to give methylated arenes (Scheme 1A)S Recently, DeShong and co-workers also reported that tetrabutylammonium triphenyldifluorosilicate, another pentacoordinated silicate, is applicable for the phenylation of allyl benzoates and aryl haUdes in the presence of a palladium catalyst. 

Gerke, H., Gies, H. and F. Liebau (1982) "Tetrabutylammonium Hydrogen Silicate Synthesis Chemical, Thermal and Crystallographie Properties", in J.S. Falcone (ed). Soluble Silicates, ACS Symposium Series, 194, American Chemical Society, Washington D.C., pp. 305-318. 

The Hiyama-Hatanaka cross-coupling reaction is a more recent arylation coupling reaction that was reported by these workers in 1988 [12e, 31]. These workers demonstrated that trimethylsilylethy-lene reacts with aryl halides in the presence of a Pd(0) catalyst, a base, and a source of fluoride ion to give styrene derivatives [12e]. The source of Pd can be (it-CjHjPdCOj, Pd(Ph3P)4, or even Pdjfdbalj the base could be a hydroxide, an acetate, a phosphane, or a phosphite and the source of the fluoride ion could be tris(diethylamino)sulfonium difluoro(trimethyl)silicate (TASF), tetrabutylammonium fluoride (TBAF) or even KF (See Scheme 1.14a). The role of this reagent is shown in the catalytic cycle... 

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