Tetrabutylammonium Chlorid

Formation of Ethers. Very high ether yields can be obtained from alcohols and phenols with dialkyl sulfates in CH2CI2 and concentrated NaOH—tetrabutylammonium chloride at room temperature or slightly elevated temperature within 1—5 h (18). Using excess aqueous caustic—N(C4H2)4HS04, unsymmetrical aUphatic ethers can be prepared with alkyl chlorides at 25—70°C in 3—4 h (19) (see Ethers). 

Difluoromethoxy-2-chloro-l,l,l-trifluoroethane and potassium fluoride produce 2-difluoromethoxy-1,1,1,2-tetrafluoroethane [50] The yield of the latter reaction is improved by adding a phase transfer catalyst or crown ether, tetra-methylammonium chlonde, tetrabutylammonium chloride, or 18-crown-6 with a solvent like sulfolane can be used for this purpose [5/] (equation 32)... 

Deng and Peng have found that certain ionic liquids catalyze the Biginelli reaction [62]. Usually, this reaction is catalyzed by Lewis acids such as InCl3, [Fe(H20)6]Cl3, or BF3.0(C2H5)2, or by acid catalysts such as Nafion-H. The reaction was found to give yields in the 77-99 % range in the ionic liquids [BMIM][PF6] or [BMIM][BF4] for the examples in Scheme 5.1-34. The reaction fails if there is no ionic liquid present or in the presence of tetrabutylammonium chloride. 

FIG. 4 Electrical potential oscillation across the octanol membrane of an octanol solution containing 5mM tetrabutylammonium chloride comprising two aqueous solutions, one containing 8mM sodium dodecyl sulfate and 5M ethanol. (Ref 19.)... 

FIG. 6 Electrical potential oscillation across the octanol membrane with sodium dodecyl sulfate as surfactant (A) and between octanol and aqueous phases (B and C). All data were obtained using the inverted U-shaped cell (al) water, (a2) 8mM sodium dodecyl sulfate and 5M ethanol, (b) octanol containing 8mM tetrabutylammonium chloride, (c) Ag/AgCl electrode, (d) KCl salt bridge, and (e) saturated KCl. (Ref. 26.)... 

There arises the question as to what causes the upper and lower potentials. The upper potential was found to be the potential of interface o/wl in the presence of tetrabutylammonium chloride in phase o as well as the potential during the induction period. The upper potential should thus derive from a mixed Galvani potential of the transfer of... 

To determine if CP was indeed lost in the chemical step the potential was held at — 1.7 V for 30s, then a positive-going scan initiated up to 1.5 V. A number of anodic peaks were observed with the largest and most significant at 1.2 V. This was unequivocally attributed to the oxidation of CP to Cl2 on the basis of a second experiment in which tetrabutylammonium chloride was added to the base electrolyte and the potential regime repeated. Hence, the chemical step after the addition of the first electron involves the ejection of the chloride anion. The identity of the species formed subsequent to this process was determined thus O Toole et al. prepared and characterised the hydrido and acetonitrile complexes (as the bipyridine derivatives) and determined their E° values as —1.46 V and —1.25 V, respectively, far removed from the observed value — 1.62 V hence neither of these species were taken as being the product. 

Similar cross-coupling reaction of another derivative of the same ring system 141 with dihydrofuran has also been described. In this case, palladium diacetate, tributylamine, triphenylphosphine, and tetrabutylammonium chloride were used to afford the product 142 in high yield (70%) <1995NN105>. 

A nucleophilic attack at an allene system of the type of 417 was described for the first time by Cainelli et al. [172], namely at 444 with the chloride ion as the nucleophile (Scheme 6.91). After the treatment of the mesylate 443 with triethylamine in the presence of lithium, sodium or tetrabutylammonium chloride, mixtures of the vinyl chlorides 445 and 447 were isolated in high yields. Since the reaction did not proceed in the absence of triethylamine, the first step should be a /3-elimination of methanesulfonic acid from 443 to generate 444, which would accept a chloride ion at the central allene carbon atom. A proton transfer to either allyl terminus of the anion thus formed (446) would lead to the products 445 and 447. 

The addition of tetrabutylammonium chloride to H solutions of [68] and [69] in deuteriated acetonitrile resulted in remarkable nmr shifts of the respective proton signals of both receptors. Of particular note were the substantial downfield shifts of the amide protons (AS = 1.28 ppm for [68] and 1.52 ppm for [69]) on addition of one equivalent of chloride. These results suggest that a significant —CO—NH-Cr hydrogen-bonding interaction contributes to the overall anion complexation process. Subsequent nmr titration curves suggesting 1 1 stoichiometry with anion complexes of [68] and [69] were found in all cases. Negligible shifts were observed under identi-... 

Addition of nitroalkanes 402 (R = Me, Bu, Ph etc.) to methyl acrylate without a solvent in the presence of Amberlyst-21 gives good yields of the esters 403436. An analogous reaction with electrophilic acetylenes, e.g. dimethyl acetylenedicarboxylate, in the presence of potassium fluoride and tetrabutylammonium chloride yields adducts 404 as mixtures of geometrical isomers437. 

The two-fold Michael addition of nitroethane to methyl propiolate in the presence of potassium fluoride and the phase-transfer catalyst tetrabutylammonium chloride leads to the diester 432. Treatment of nitroethane with methyl propiolate under these conditions, followed by methyl vinyl ketone, leads to the mixed adduct 433460. 

Carbon dioxide is one of the most abundant carbon resources on earth. It reacts with an epoxide to give either a cyclic carbonate or a polycarbonate depending on the substrates and reaction conditions. Kinetic resolution of racemic propylene oxide is reported in the formation of both cyclic carbonate and polycarbonate. The fe ei value defined as ln[l-(conversion)(l+%ee)]/ln[l-(conversion)(l% ee)] reached 6.4 or 5.6 by using a Co(OTs)-salen complex with tetrabutylammonium chloride under neat propylene oxide or using a combination of a Co-salen complex and a chiral DMAP derivative in dichloromethane, respectively. 

Co(OAr)-salen complex [Ar = 2,4-(N02)2CeH3] with tetrabutylammonium chloride under neat propylene oxide, quite similar to the conditions for the cyclic carbonate synthesis, give polycarbonate with fe ei of 3.5. ° Without any additives, the use of Co(OAc)-salen provides the polycaronate with fe ei of 2.8. ... 

MacKinnon and coworkers [391-393] have studied a number of organic compounds as additives and have shown that tetrabutylammonium chloride improves surface morphology and current efficiency during zinc electrowinning from acidic chloride solutions. A similar influence was observed using other tetraalkylammo-nium compounds as additives [371, 374, 375, 394],... 

Formation of the antiasthmatic imidazoquinoline compound was achieved through the closure of the central pyridine ring in a heteroaryl Heck reaction (4.28.), The best results were obtained in the presence of tetrabutylammonium chloride without any added ligand (Jeffery s ligand free variant).32... 

The ready insertion of carbon monoxide into furanylpalladium complexes is impressively demonstrated by the reaction depicted in 6.63. The iodofiirane derivative was reacted with carbon monoxide in the presence of tetrabutylammonium chloride. Following an aqueous workup the appropriate carboxylic acid was isolated in good yield (6.63.).94 It is worth pointing out, that due to the mildness of the reaction conditions the Heck coupling of the olefin moiety could be excluded. 

The use of the heteroaryl Heck reactions extends beyond fine chemicals synthesis. Polythiophenes were prepared starting from 3-octyl-2-iodotiophene by heating in the presence of palladium acetate and tetrabutylammonium chloride (6.91.),122 The arylation of benzothiophene has also been achieved under the same conditions.123... 

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