Tetrabutylammonium hydrogen sulfate

Fluonnated allylic ethers are prepared under phase-transfer catalysis (PTC) in the presence of tetrabutylammonium hydrogen sulfate (TBAH) fJ] (equation 2)... 

The submitters purchased tetrabutylammonium hydrogen sulfate with a purity of 97% from Fluka AG, Buchs, Switzerland. This reagent was obtained by the checkers from Aldrich Chemical Company, Inc. 

Tetrabutylammonium hydrogen sulfate Ammonium, tetrabutyl-, sulfate (1 1) (8) 1-Butanaminium, N,Af,N-tributyl-, sulfate (1 1) (9) (32503-27-8)... 

Finally, Jessop and coworkers describe an organometalhc approach to prepare in situ rhodium nanoparticles [78]. The stabilizing agent is the surfactant tetrabutylammonium hydrogen sulfate. The hydrogenation of anisole, phenol, p-xylene and ethylbenzoate is performed under biphasic aqueous/supercritical ethane medium at 36 °C and 10 bar H2. The catalytic system is poorly characterized. The authors report the influence of the solubility of the substrates on the catalytic activity, p-xylene was selectively converted to czs-l,4-dimethylcyclohexane (53% versus 26% trans) and 100 TTO are obtained in 62 h for the complete hydrogenation of phenol, which is very soluble in water. 

The mesogenic units with methylenic spacers were prepared by reacting the sodium salt of either 4-methoxy-4 -hydroxybiphenyl or 4-phenylphenol with a bromoester in DMF at 82° C for at least 4 hours in the presence of tetrabutylammonium hydrogen sulfate (TBAH) as phase transfer catalyst. In this way, ethyl 4-(4-oxybi-phenyl)butyrate, ethyl 4-(4-methoxy-4 -oxybiphenyl)butyrate, ethyl 4-(4-oxybiphenyl)valerate, ethyl 4-(4-methoxy-4 -oxybiphenyl)-valerate, n-propyl 4-(4-oxybiphenyl)undecanoate and n-propyl 4-(4-methoxy-4 -oxybiphenyl)undecanoate were obtained. These esters were hydrolyzed with base and acidified to obtain the carboxylic acids. The corresponding potassium carboxylates were obtained by reaction with approximately stoichiometric amounts of potassium hydroxide. Experimental details of these syntheses were described elsewhere (27). 

The dimer of chloro(l,5-hexadiene)rhodium is an excellent catalyst for the room temperature hydrogenation of aromatic hydrocarbons at atmospheric pressure. The reaction is selective for the arene ring in the presence of ester, amide, ether and ketone functionalities (except acetophenone). The most useful phase transfer agents are tetrabutylammonium hydrogen sulfate and cetyltrimethylammonium bromide. The aqueous phase is a buffer of pH 7.6 (the constituents of the buffer are not critical). In all but one case the reaction is stereospecific giving cis products... 

There is a case where the resnlts of the electrode and chemical oxidation coincide (see Scheme 2.20). Calix[8]pyrrole was prepared from 3,3, 4,4 -tetraethyl-2,2 -bipyrrole during oxidative electrolysis in dichloromethane nsing platinum anode, tetrabutylammonium hydrogen sulfate as the... 

Poly-(L)-leucine-l,3-diaminopropane (740mg, O.lOmmol, 1.0mol%) and tetrabutylammonium hydrogen sulfate (l.Og, 2.95 mmol, 30mol%) were placed in a flask with a stirrer bar. Toluene (2 ml), sodium hydroxide solution (5M, 30 ml, 10 eq.) and aq. hydrogen peroxide (30%, 15 ml, 10 eq.) were added and stirred for three hours. The aqueous layer was removed and sodium hydroxide solution (5M, 30 ml, 10 eq.) and aq. hydrogen peroxide (30%, 15 ml, 10 eq.) were added and the mixture was stirred overnight. The aqueous layer was removed to leave the activated polyleucine gel. 

A quantity of tetrabutylammonium hydrogen sulfate 28.7 g (Aldrich), that has been recrystallized from acetone, is added to 300 mL of warm methanol in a 500-mL beaker. To this is added a solution of aqueous perrhenic acid (28.0 g, 80 to 85%, titrated 75.7%) (Alfa) with stirring. The total volume is then reduced by boiling to 125 mL, and the solution is then cooled slowly to 0 °C yielding white needles of [CH3(CH2)3]4NRe04. The supernatant liquid is further condensed to 50 mL and the resulting needles are combined with the initial crystalline product and twice recrystallized from methanol to give 30.8 g (74% yield) of product (mp 236-237 °C). 

Permethylation of carbohydrates.1 Permethylation of carbohydrates in a solid-liquid system is not possible because of lack of solubility in benzene or methylene chloride. The difficulty can be circumvented by reaction of peracetylated sugars with methyl bromide in C6H6-aqueous NaOH with tetrabutylammonium hydrogen sulfate as catalyst. 

Tetra>/i-butylammonium periodate, (C4H9)4NI04. Mol. wt. 433.4, m.p. 158-159°, water insoluble, unstable to light. The reagent is prepared in quantitative yield by reaction of sodium periodate with tetrabutylammonium hydrogen sulfate in aqueous solution. 

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