Tetrapropylammonium perchlorate

Figure 9.2 Cyclic voltammogram for 5 mM dioxygen (02, at 1 atm) in pyridine (0.1 M tetrapropylammonium perchlorate) at a platinum electrode (area 0.23 cm2). Scan rate, 0.1 V s-1. Saturated calomel electrode (SCE) versus NHE, +0.244 V.

A number of aromatic nitriles including benzonitrile have been reduced electroche-mically in DMF-tetrapropylammonium perchlorate to give solutions of relatively stable anion radicals whose epr spectra have been recorded [148]. These anion radicals are capable of transferring and electron to more difficulty reducible species such as carbon dioxide [149] ... 

Abbreviations are CV — cyclic voltammetry DMF — N,N-Dimethylformamide E swp — potential sweep E° — standard potential — peak potential E — half-peak potential E — half wave potential M — mol/L i eCN — acetonitrile pol — polarography rot Pt dsk — rotated Pt disk SCE — saturated calomel electrode TBABF — tetrabutylammonium tetrafluoroborate TBAl — tetrabutylammonium iodide TBAP — tetrabutylammonium perchlorate TEABr — tetraethylammonium bromide TEAP — tetraethylammonium perchlorate THF — tetrahydrofu-ran TPACF SO — tetrapropylammonium trifluoromethanesul-fite TPAP — tetrapropylammonium perchlorate and wr — wire. 

Good yields of oi-aminothioethers were obtained on electroreduction of, ]J-disubstituted thioamides in acetonitrile containing tetrapropylammonium perchlorate and an alkylating agent. 2-Aminothioethers and 2-aminoethers were obtained from N-phthalimi-doaziridines by reaction with thiols and alcohols respectively, followed by reduction of the resultant B-hydrazino-thioethers and -ethers. 

The most commonly used quaternary ammonium salts are tetrabutylammonium perchlorate (TBAP), tetrafluoroborate (TBAT), the halides (TBACl, TBAB, and TBAI), and the corresponding tetraethylammonium salts, such as the perchlorate (TEAP), but also the tetramethyl- or tetrapropylammonium salts have been employed the former cannot undergo a base-promoted Hofmann elimination. However, evidence has been found for the formation of trimethylammonium methylide [460]. In nonpolar solvents it may be necessary to employ tetrahexyl- or tetraoctylammonium salts. The tetraalkylammonium ions are soluble in many nonaqueous media, and they may be extracted from an aqueous solution by means of chloroform or methylene chloride [461,462], and tetraalkylammonium salts may thus be prepared by ion extraction [462]. Tetrakis(decyl)ammonium tetra-phenylborate is soluble even in hexane [442,443]. 

Acetonitrile (Ajax Chemicals HPLC Grade) solutions of constant calixarene anion (host) concentration and varying tetramethylammonium ion, choline or acetyl choline (guest) concentrations were prepared by appropriate dilutions of 10 mol L stock solutions of the tetrapropylammonium salts of the calixarenes, tetramethylammonium trifiate, choline triflate and acetylcholine perchlorate. Spectra were recorded in the range 200-350 nm on a Hewlett-Packard 8452 Diode Array spectrophotometer. Nonlinear least-squares fitting of absorbance vs. composition data to models of the reaction system was conducted using a program written locally by Dr. E. S. Kucharski. 

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