Acetonitrile-tetrabutylammonium

Electrochemical fluorination 168,169> is a commercial process for perfluorina-tion of aliphatic compounds. The reaction is performed in liquid hydrogen fluoride -potassium fluoride at a nickel anode. The mechanism is not known free fluorine cannot be detected during electrolysis, so it seems probable that fluorination is a direct electrochemical reaction. Theoretically, hydrogen fluoride-potassium fluoride should be a very oxidation-resistant SSE, and it might well be that the mechanism is analogous to that proposed for anodic acetamidation of aliphatic compounds in acetonitrile-tetrabutylammonium hexafluorophosphate 44 K... 

Under this heading a few borderline cases between direct and indirect electrochemical reactions can be included. Dihalocarbenes are probably intermediates in the cathodic reduction of certain polyhalogenated compounds172) as an example, cathodic reduction of carbon tetrachloride at a mercury cathode in acetonitrile-tetrabutylammonium bromide in the presence of tetramethylethylene gave a low yield of l,l-dichloro-2,2,3,3-tetramethylcyclopropane ... 

This value was obtained (Geske, 1959) with Pr4NOAc (0-3 mM) in acetonitrile/ tetrabutylammonium perchlorate (O l M). 

Column. Amino-propyl bonded silica (Spherisorb S5NH2, 5 qm, 25 cm x 4 mm internal diameter). Eluent. Acetonitrile tetrabutylammonium phosphate, 0.005M, pH 7.5 (85 15). 

DC of substituted phenylisopropylamines can be easily accomplished. Both normal phase and octadecyl-substituted silica (reversed-phase) plates were used with the chloroform/triethanolamine and water-acetonitrile/ tetrabutylammonium chloride carrier/displacer pairs, respectively. Only a few exceptionally behaving compounds moved faster or slower than the displacer front in the normal-phase and reversed-phase systems, respectively. The displacement chromatogram of HPDC can be characterized as series of sequentially increasing steps of the weight distribution or that of ultraviolet absorbance. This is the reason why off-line detection is used to characterize HPDC. D-TLC would have a similar profile, but specific detection may improve differentiation of the individual components. Further possibility is given by the application of spacers. 

Ion Mobilities, Fig. 2 Walden product (A rj) as function of temperature and solvent composition. Butyl triisoamylammonium tetraphenylborate in ethanol ( ), 1-propanol ( ), and acetonitrile ( ). Tetrabutylammonium perchlorate in 1-propanol (T) and acetonitrile (A). LiBr (O) in acetonitrile-propylene carbonate mixtures at temperatures from 25 °C to 75 °C... 

Besides the well-known lower basicity of ethanol, these data illustrate the greater acidity of benzoxazolium compared with benzothiazolium. The relative pK. values of the quaternary salts obtained in acetonitrile when treated with tetrabutylammonium hydroxide are 18.3 and 17.6, respectively (25). Those of 2-methyl 4-phenyl thiazolium and 2.4-dimethyl thiazolium are 20.5 and 21.8 under the same conditions (25). 

Bromine electrogeneration was carried out from tetrabutylammonium bromide in 0,1 M NaClO acetonitrile solution with 100 % current yield. 

Dehydrochlorination of bis(tnfluoromethylthio)acetyl chloride with calcium oxide gives bis(trifluoromethylthio)ketene [5] (equation 6) Elimination of hydrogen chloride or hydrogen bromide by means of tetrabutylammonium or potassium fluoride from vinylic chlorides or bromides leads to acetylenes or allenes [6 (equation 7) Addition of dicyclohexyl-18-crown-6 ether raises the yields of potassium fluoride-promoted elimination of hydrogen bromide from (Z)-P-bromo-p-ni-trostyrene in acetonitrile from 0 to 53-71 % In dimethyl formamide, yields increase from 28-35% to 58-68%... 

Acetonitril wird an Zinn in DMF/Acetonitril (5%) (Leitsalz Tetrabutylammonium-perchlorat) bei 45°/—2,9 V zu Tetramethyl-zinn gespalten3 (s.a.S. 624). 

Pentyl- bzw. Hexylbromid bilden in Acetonitril (Leitsatz Tetrabutylammonium-tetra-fluoroborat) an PlatinHeptansaure-nitril (42% d.Th. 80% Umsatz) bzw. Octansaure-ni-tr tl (41% d.Th. 89% Umsatz)2. 

For the tetrabutylammonium salts of substituted acetate the quarter wave potentials have been determined by chronopotentiometry in acetonitrile. The ease of oxidation, as reflected in the Ej -values, decreases with increasing strength of the acid [88]. 

Fig. 5.5 Chromatogram ofchlor-prothixene hydrochloride CRS which contains 2.7 % ofthe f -isomer. (Column 4 x 120 mm hypersil BDS [3 pm]. Mobile phase 6.0 g potassium dihydrogen phosphate, 2.9 g sodium lauryl sulphate, 9.0 g tetrabutylammonium bromide 550 ml water, 50 ml methanol and400 ml acetonitrile, flow rate 1.5 ml/min and detection wavelength 254 nm.)...

Figure 10. Slurry electrochemical voltage spectroscopy experiments with tetragonal [Si(Pc)0]n and various perfluoroalkyl-sulfonates (as the tetrabutylammonium salts in acetonitrile).

Direct introduction of the bromodiazirine into molten tetrabutylammonium fluoride (at 63°C) to effect halogen exchange leads to an explosion. Use of acetonitrile at 0°C as solvent gives a low yield of the required fluorodiazirine. 

Electrolytic oxidation of acetonitrile solutions of monomer mixtures of dithioenopyrrole 23 and dithienothiophene 15a using tetrabutylammonium perchlorate as an electrolyte can produce poly(dithienopyrrole-dithienothiophene) copolymer which shows good electrochromic <1994EAC2159> characteristics. Similarly, films of poly(dithienopyrrole-thionapthene indole) and poly(dithienopyrrole-thionapthene indole) co-polymers can be obtained from DTT and DTP with thionapthene indole 85 (TNI) <1996SM(82)11>. 

In 1985, Sullivan et al. reported a voltammetric study on (Bipy)Re[CO]3Cl in acetonitrile with tetrabutylammonium hexafluorophosphate (TBAHFP) as the supporting electrolyte. 

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. 

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