Tetrabutylammonium ion

The crown ethers and cryptates are able to complex the alkaU metals very strongly (38). AppHcations of these agents depend on the appreciable solubihty of the chelates in a wide range of solvents and the increase in activity of the co-anion in nonaqueous systems. For example, potassium hydroxide or permanganate can be solubiHzed in benzene [71 -43-2] hy dicyclohexano-[18]-crown-6 [16069-36-6]. In nonpolar solvents the anions are neither extensively solvated nor strongly paired with the complexed cation, and they behave as naked or bare anions with enhanced activity. Small amounts of the macrocycHc compounds can serve as phase-transfer agents, and they may be more effective than tetrabutylammonium ion for the purpose. The cost of these macrocycHc agents limits industrial use. 

To determine secondary alkanesulfonates in sewage wastewaters, solid phase extraction (SPE) and a single-step procedure which combines elution and injection port derivatization for analysis with GC-MS were developed [36]. Again a tetrabutylammonium ion pair reagent was employed both to elute the secondary alkanesulfonates as their ion pairs from CI8-bonded silica disks and to derivatize sulfonate ion pairs under GC injection port conditions. Secondary alkanesulfonates were effectively recovered from samples of raw sewage (>92%) and from primary (>98%) and secondary (>85%) effluents. No... 

Large bound monovalent cations, e.g. tetrabutylammonium ions, are too large to penetrate any of the hydration regions. However, the smaller lithium, sodium and potassium ions are able to penetrate the outermost hydration region of the neutralized polyacid and this is accompanied by volume increases (Figure 4.9). These cations are probably not site-bound but are mobile in the outer cylindrical region of hydration (Figure 4.10). 

Girault and Schiffrin [6] and Samec et al. [39] used the pendant drop video-image method to measure the surface tension of the ideally polarized water-1,2-dichloroethane interface in the presence of KCl [6] or LiCl [39] in water and tetrabutylammonium tetraphenylborate in 1,2-dichloroethane. Electrocapillary curves of a shape resembling that for the water-nitrobenzene interface were obtained, but a detailed analysis of the surface tension data was not undertaken. An independent measurement of the zero-charge potential difference by the streaming-jet electrode technique [40] in the same system provided the value identical with the potential of the electrocapillary maximum. On the basis of the standard potential difference of —0.225 V for the tetrabutylammonium ion transfer, the zero-charge potential difference was estimated as equal to 8 10 mV [41]. 

Large molecules or ions can also be trapped inside the zeolitic framework during cristallization. Tetrapropy1ammonium ions in ZSM-5 zeolite and tetrabutylammonium ions inZSM-11 zeolite (intact in their respective frameworks) occupy the channel intersections and their alkyl chain extend in the linear and zig-zag channels in ZSM-5 zeolite or in the perpendicular linear channels of ZSM-11 zeolite. 

In ZSM-5 zeolite, almost every channel intersection is occupied by a tetrapropylammonium ion. Oppositely, tetrabutylammonium ions occupy preferentially the large cavities in ZSM-11 zeolite, the small cavities being only partially occupied. Their alkyl chains extend in the channel system in order to fill completely the available channel length (11). 

Figure 8. High resolution CP/MA.S solid state C-NMR spectra of tetrapropyl- and tetrabutylammonium ions in ZSM-5 and ZSM-11 zeolites respectively. 11 Reproduced with permission from Ref. 11 Copyright 1981, Butterworth and Co (Publishers) Ltd c ".

Example ion-pair liquid chromatography of amino acids. Amino acids are zwitterions. The amino group can form an ion-pair with an alkanesulfonate ion (such as octanesulfonate), and the carboxyl group can form an ion-pair with a tetrabutylammonium ion, depending on the pH of the solution. 

The addition of a surfactant counter-ion reduced the retention factor at low pH due to the surface modification of the stationary phase material. Covering the surface of the stationary phase with the surfactant reduces the hydro-phobicity of the stationary phase material. The addition of the tetrabutyl-ammonium counter-ion increased the retention factor at high pH. The pKa of the indole acetate was 5.15 without surfactant, 4.85 with octyl sulfate ion, and 5.60 with tetrabutylammonium ion. That is, the addition of a same-charged hydrophobic ion reduced the pKa value, and the addition of the counter-ion increased the pKa value. The difference in the pKa value on the addition of surfactant is not constant it is affected by the kind of ion and the concentration. It is difficult to estimate the pKa change. 

When ions of valence 2 or higher are used as an electrolyte in the mobile phase and if this ion is a counter ion to the analyte or pairing ion in ion-pair chromatography. E.g., if tetrabutylammonium ion is used as a pairing ion at pH=9 in the presence of PO in the electrolyte, it will probably not behave as ideally as at pH=2 where phosphate will be in the H2PO4 form. 

Liquid-liquid partitioning cleanup is generally directed to removal of the matrix constitutents from the aqueous extract into organic immiscible solvents (14, 298, 299, 302, 308). Unfortunately, tetracyclines cannot be quantitatively recovered into organic immiscible solvents at any pH value because of their high polarity. However, recoveries higher than 85% were reported when tetrabutylammonium ions were employed in the ion-pair extraction of oxytetracycline and tetracycline into dichloromethane at pH 8.2 (297). 

Aromatic dithiols are stable and can be stored as such. 9,10-Phenanthrenedithiol, for example, is a crystalline (m.p. 134 °C), colorless and odorless solid.23 Other dithiols (such as H2bdt and H2tdt) are commercially available. Dithiols of aliphatic alkenes are prone to decomposition and polymerization.17 They are best converted into alkali metal salts or salts of organic cations such as the tetrabutylammonium ion. These salts usually have a considerable shelf life. 

Takayanagi, T. and S. Motomizu. 2007. Pseudo-homogeneous micelle extraction of ion-associates formed between tetrabutylammonium ion and some aromatic sulfonate ions into nonionic surfactant micelle studied through the mobility measurements in capillary zone electrophoresis. J. Chromatogr. A 1141 295-301. 

Deposition of platinum metal In the case of platinum no solid product was found. The ionic liquid darkened more and faster the smaller the distance between the surface of the ionic liquid [EMIM][TfO] containing tetrabutylammonium hexachloro-platinate ([n-Bu4N]2[PtCl6]) and the Ar/H2-plasma (3 1, overall pressure 100 Pa) was chosen. So far no other ionic liquid has been tested. The rate constant for the reduction of the tetrabutylammonium ion with a hydrated electron is only 1.4 x 106 LmoH1 s 1, hence the main rival pathway for reduction of platinum(IV) is the reduction of the imidazolium ion of the ionic liquid. As in the case of copper, a suitable platinum salt - maybe made by electro-oxidation of metallic platinum in a suitable ionic liquid - has to be found. 

Figure I. Single-ion standard Gibbs free energy of transfer from water to water + acetone mixtures based on S.F.T. calculations for the tetrabutylammonium ion (mole-fraction...

The structure of the isoporous sulfonic acid resins is as fully accessible for the tetrabutylammonium ions as are the standard resins with 1-2% DVB (Table 4). The isoporous resins irrespective of the type and amount of erosslinking can be completely saturated with the tetrabutylammonium ions. On the contrary, it is well known that the tetrabutylammonium ion uptake of standard SDVB resins fall sharply with the increasing degree of crosslinking. 

Elegant studies of electrocapillarity of a nonpolarized ITIES by Gavach et al. [48] showed that the tetraethyl-, tetrapropyl- and tetrabutylammonium ions are not adsorbed within the compact layer and suggested that the interface is made of two space charge layers, described by the Gouy-Chapman theory, on either side of a central compact layer [49-51]. In a nonpolarized ITIES, the potential drop across the interface cannot be altered independently of the chemical potential of a salt of ionic constituents in either of the phases. The degree of specific adsorption cannot therefore be quantitatively estimated at a nonpolarized interface [28]. 

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