Resins quaternary ammonium

Strongly basic anion exchangers (polystyrene quaternary ammonium resins). These resins (Duolite A113, Amberlite 400, etc.) are usually supplied in the chloride form. For conversion into the hydroxide form, treatment with 1M sodium hydroxide is employed, the volume used depending upon the extent of conversion desired two bed volumes are satisfactory for most purposes. The rinsing of the resin free from alkali should be done with de-ionised water free from carbon dioxide to avoid converting the resin into the carbonate form about 2 litres of such water will suffice for 100 g of resin. An increase in volume of about 20 per cent occurs in the conversion of the resin from the chloride to the hydroxide form. 

Paskach, T. J., Lieker, H.-R, Reilly, P. J., and Thielecke, K., High-performance anion-exchange chromatography of sugars and sugar alcohols on quaternary ammonium resins under alkaline conditions, Carb. Res., 215,1, 1991. 

Another method for generating an epoxidation catalyst on a solid support is to simply absorb or non-covalendy attach the catalyst to the solid support <06MI493>. Epoxidation of olefin 6 with mCPBA and catalyst 8 provides 7 in quantitative yields and with 89% ee. The immobilization of 8 on silica gel improves the enantioselectivity of the reaction providing 7 with 95% ee. Recycling experiments with silica-8 show a decrease in both yield and the enantiomeric excess for each cycle (45% ee after 4 cycles). This is attributed to a leaching of the catalyst from the silica gel. Two other solid supports, a Mg-Al-Cl-LDH resin (LDH) and a quaternary ammonium resin (Q-resin) were also examined. It was expected that ionic attraction between 8 and the LDH or Q-resin would allow the catalyst to remain immobilized through multiple cycles better than with silica gel. Both of these resins showed improved catalytic properties upon reuse of the catalyst (92-95% ee after 4 cycles). 

The quaternary ammonium resin (e.g. Amberlite IRA-904) (2 mol equivalent) and the carboxylic acid (l mol equivalent) are shaken in EtOH (25 ml) for ca. 30 min at room temperature. The resin is collected, washed with MeCN (2 x 15 ml), and added to the alkylating agent (4 mol equivalent). The system is stirred at 20-25 °C for 10-20 h and then filtered. Fractional distillation of the filtrate yields the ester. 

Method C. (tri-phase catalysis) NaCN (0.6 g) in H20 (1 ml) and the haloalkane (0.6 mmol) in PhMe (1 ml) are shaken for 2 min with the quaternary ammonium resin (74 mg), obtained by reaction of Me2BuN with poly-4-chloromethylstyrene. The mixture is kept at 110°C for ca. 5.5 h and it is then filtered and extracted with CH2C12 (3 x 10 ml). The dried (MgS04) extracts are evaporated to yield the nitrile. 

Ions with the same charge as the resin are excluded. (The quaternary ammonium resin excludes K+.) The counterion, Cl, is not excluded from the resin. There is no electrostatic barrier to penetration of an anion into the resin. Anion exchange takes place freely in the quaternary ammonium resin even though cations are repelled from the resin. 

A compound prepared and first described as nicotinium dichromate (NDC) by Palomo et al.,379 was later shown by X-ray-crystal analysis380 to be a betainic mixed anhydride of nicotinic and chromic acid (NACAA). Because of its unique structure, it deserves a close scrutiny of its oxidative properties.381 Replacement of the chloride anion in the quaternary ammonium resin, Dowex 1-X8, for the dichromate anion, leads to a polymer supported dichromate, which is able to make selective benzylic oxidations.382 Finally, poly[vinyl(pyridinium dichromate)] (PVPDC), a polymeric analogue of PDC, must be mentioned whose use in the oxidation of alcohols allows for a very easy work-up.383... 

Pyridinium and quaternary ammonium resins react with chromium trioxide, producing polymer-supported complex chromates that oxidize alcohols, and provide a very facile work-up.427... 

Polymer-supported nucleophilic radiolabelling reactions with [18F]fluoride and [nC]cyanide ions on the surface of quaternary ammonium resins (337, 338) have been found323 valuable in radiopharmaceutical syntheses where fast, simple and easily automated chemical operations are necessary. 3-[18F]-diazepam has been obtained in 30% yield by this method323. 

As indicated in Table 5.3d, significant negative enthalpies and entropies of exchange for the exchange of halide ions on quaternary ammonium resins could be interpreted in terms of pure electrostatic interactions. However such a coulombic model invoking solvated ion size or distance of closest approach fails to conform to the observed affinity order I > Br > CI > F . If one includes a larger polyatomic anion such as perchlorate, Cl 04 the experimental sequence is Cl 04 > I > Br"> Cr > F" which clearly contradicts any simple coulombic attraction theory. 

The use of anion-exchange resins to remove some of NOMs from drinking water is well documented. Quaternary ammonium resins are normally used in the chloride form, with the chloride ions being replaced by the organic anions. Regeneration is achieved with brine or caustic brine. Trihalomethane (THM) precursors can be significantly removed. 

C1, OH, NO3 etc. quaternary ammonium resin tertiary amino resin secondary amino resin primary amino resin... 

Sanchez J.M., Hidalgo M., Salvado V. A comparison of the separation behavior of some new coordinating resins and commercial quaternary ammonium resins with reference to their separation of goldJOI) and palladium(II) in hydrochloric acid media. Solvent Extraction and Ion Exchange 2004 22 285-303. 

A water-soluble metabolite of indole-3-acetic acid is formed by certain strains of Pseudomonas savastanoi. The material has been isolated from culture filtrates of this organism and purified by adsorption on charcoal and by ion-exchange chromatography on sulfonic acid resins and quaternary ammonium resins (Hutzinger and Kosuge, 1968). The isolated metabolite was identified as indole-3-acetyl-e-L-lysine (CXII) by chemical means and by infrared and ultraviolet spectroscopy. 

DOWE) 50W-X4 sulfonic acid and DOWE) S) 1-X4 quaternary ammonium resins were eluted consecutively with 3 N NaOH, hot water, methanol, cold water, 3 N HCl, hot water, methanol, and cold water at least four times. The purity of the resins was checked by measuring the surface tension, conductance, ultraviolet absorption, and amount of acid or base required for neutralization of the wash water. The resins were converted to the and OH" forms, respectively, and mixed. 

The S-alkylation of the sodium salt (72) of thiosaccharin is the basis of a new route to thiols from alkyl halides (Scheme 51). The conversion of alkyl halides (RX) to thiolacetates (RSCOMe), and hence to thiols by saponification, has been shown to be effected by a quaternary ammonium resin with thiolacetate as counterion. Thiolacetates are also available in one step from alcohols in... 

Sulfur-containing resins specific for mercury uptake have been made from polyepichlorohydrin and thioglycolic acid or thiourea, but they are difficult to regenerate, just as are known selective resins of the thiol type (7). However, cationic mercury is readily adsorbed by commercial iminodiacetic acid resins, from which it can be removed as the anionic chloro complex by a brine wash alternatively, when there is already chloride present in the raw water the mercury can be adsorbed as the chloro complex on a commercial quaternary ammonium resin, from which it can be recovered by a complexing agent such as sodium sulfite (8). 

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