Anion weakly basic

Dowex 4-X4 1.6 0.70 Weakly basic anion exchanger with tertiary amines on an acrylic matrix for the deionization of carbohydrates. Use at pH <7. 

Weakly basic anion resins derive their functionality from primary (R-NH), secondary (R-NHR ), tertiary (R-N-R 2), and sometimes quaternary amine groups. The weakly basic resin readily absorbs such free mineral acids as hydrochloric and sulfuric, and the reactions may be represented according to the following ... 

The symbol R3N represents the complex weakly basic anion-exchanger radical. The symbol R,N represents the complex strongly basic anion-exchanger radical. 

Demineralization by SAC(H)/WBA(OH) Removes virtually all TDS except silica and carbon dioxide. The weakly basic anion cuts operating costs through a significantly enhanced capacity and reduced regeneration demands. However any sodium slip from the cation unit passes through the anion and increases the conductivity of the treated water. 

Demineralization by SAC(H)/WBA(OH)/Degassing/MB Removes virtually all TDS, including carbon dioxide and silica. When the RW is high in chlorides and sulfates, the use of a weakly basic anion reduces both the operating costs and the size of the MB. 

The values of [HA] and [A ] in this expression are the equilibrium concentrations of acid and base in the solution, not the concentrations added initially. However, a weak acid HA typically loses only a tiny fraction of its protons, and so [HA] is negligibly different from the concentration of the acid used to prepare the buffer, [HA]initia. Likewise, only a tiny fraction of the weakly basic anions A- accept protons, and so [A-] is negligibly different from the initial concentration of the base used to prepare the buffer. With the approximations A ] [base]initia and [HA] [acid]initia, we obtain the Henderson-Hasselbalch equation ... 

As mentioned in the historical synopsis (Section 5.1), Levine121 perfected the compendial partition column procedure in which aspirin in chloroform is first trapped in an immobile phase of sodium bicarbonate on a column of siliceous earth (celite) then eluted with a solution of acetic acid in chloroform and measured spectrophotometrically. This has been also used for separation in combination products.80 For the determination of salicylic acid in presence of aspirin by this method, see Section 5.61. Ion exchange columns filled with strongly or weakly basic anion exchange resin in the acetate or chloride cycle have also been used for separation of aspirin in combination products. 122 123/l2lf This has also been adapted for a student experiment.125 A Sepha-dex-G25 column has been used for the separation of aspirin from salicylic acid.126... 

Kulprathipanja, S., Oroskar, A.R., and Priegnitz, J.W. (1989) Separahon of citric add from fermentahon broth with a weakly basic anionic exchange resin adsorbent. U.S. Patent 4,851,573. 

Salts of polyatomic cations, such as Bi + and Te, are obtained from melts and stabilized by large weakly basic anions such as AICIJ ... 

Weakly basic anion exchange Polyamine polystyrene or phenol-formaldehyde 0-9 Anionic metal complexes, amino acids, vitamins... 

Detoxification of hydrolysates was accomplished in a continuous ion-exchange bench-scale unit. The resins used were Dowex 1 (50/100 mesh, density 0.71 g/cm3), weak basic anion exchanging, and Dowex-50W (50/ 100 mesh, density 0.80 g/cm3), strong acidic cation exchanging. 

Poly(ethyleneimine) cross-linked (CPEI) with ethylenedichloride forms stable complexes with copper (II) as well as with cobalt (II). The RC1 type of cross-linked poly(ethyleneimine) having an anion-exchange capacity of 6.8 meq g 1 retains copper from CuS04 and cobalt from 1 M aq. CoCl2 solutions [55], PEI is by itself a weak basic anion-exchange resin and forms stable complexes with anions and cations. The process is probably accompanied with chelate ring formation ... 

It is noteworthy that the use of DMSO in this manner contrasts with its established usage in elimination reactions. DMSO has normally been used because of its ability to promote eliminations by weakly basic anions (Parker, 1971), its effectiveness in enhancing the basicity of alkoxides (Cram et al., 1961), and also because it allows variation of base without the usual variation of solvent (Dolman and Stewart, 1967). Full details of such studies and their importance in the development of an understanding of elimination mechanisms are given in a recent text (Saunders and Cockerill, 1973).8... 

If the conjugate-base-dissociation mechanism is the correct one, the lower substitution rates observed with nitrite, acetate, and azide may be considered to arise because these weakly basic anions are less effective than methoxide in generating conjugate base CB in the preliminary acid base equilibrium. 

Anion Exchange Celluloses Aminoethylcellulose, a weakly basic anion exchanger, is prepared in the reaction of cellulose with a-aminoethyl-sulfuric acid in the presence of sodium hydroxide ... 

Immobilization. We have worked with different carriers for immobilization. Active immobilized preparations have been obtained by adsorption on macroporous, weakly basic anion exchange resins, and on nonionic adsorbent resins. Resins of both acrylic and phenol-formaldehyde have been used (8). In the following examples we have used lipase immobilized on nonionic adsorbent acrylic resin. 

In the presence of MAO or AlMe3 the 14-electron species is stabilized by reversible adduct formation, giving [Cp2Zr(//,-Me)2AlMe2]+.101 Very weakly basic anions such as B(QF5)4 are required to stabilize the cationic metallocene species anions have a strong effect on catalytic activity.105... 

Since about 1990, Aubke and colleagues have used HSO3F as a medium for synthesis of a very wide range of compounds containing carbonyl cations of transition metals in association with extremely weakly basic anions. 

The methods of preparation of these species in superacid solution and the structures of many of the cations in association with very weakly basic anions were reviewed by Gillespie and Passmore [49]. Typical generation of the cations in solution involved oxidation of the appropriate element with bis(fluorosulfuryl) peroxide, S2OeF2, in HS03F to yield the cation and S03F which is both the reduction product of the oxidant and the base of the solvent ... 

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