Cations weakly basic anions

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. 

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

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 ... 

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 ... 

It was shown in Sec. 11.3.4.3 that Aubke, Willner and colleagues [47] recently carbonylated transition metal fluorosulfates and other compounds in neat SbF5 to generate naked transition metal carbonyl cations in association with the very weakly basic anion Sb2Ff,. 

The cation exchange step is exactly as described for the Strong Acid Cation (SAC)-Strong Base Anion (SBA) process but now the acidic cation column effluent passes down a column of weakly basic anion exchange resin. The strong mineral acids are taken up by the anion resin through addition to form the acid salt forms, whilst the too weakly acidic dissolved carbon dioxide and silica pass through unaffected (Chapter 4). 

Most ions constituting ionic liquids can be categorized according to their Lewis acid/base properties (i.e., their capability to accept or to donate an electron pair) nevertheless, some ions may be considered according to the Bronsted definition, i.e., on the basis of their ability to accept or donate a proton. Typical ionic liquids are those based on neutral or very weakly basic anions (BF4, PF, NOf, CHsSO, 4 f2N ) and neutral (tetraalkylammonium, dialkyl-pyrrolidium, trialkylsulfonium) or weakly acidic cations (1,3-dialkylimidazolium and 1,2,3-trialkylimidazolium) (Figure 4.1). 

Salts That Yield Neutral Solutions Salts That Yield Acidic Solutions Salts That Yield Basic Solutions Salts of Weakly Acidic Cations and Weakly Basic Anions... 

Salts of Weakly Acidic Cations and Weakly Basic Anions... 

For a large number of macroporous styrene—DVB copolymers, sulfo-nated cation exchangers KU-23, and weak basic anion exchangers AN-221, the specific volumes and the true and apparent densities were measured independently and the values of and F were correlated in accordance with Eq. [3.3]. The coefficients a and b of the above equation, obtained after statistical treatment of all the results [250], are given in Table 3.1. 

WBA = weak basic anion exchanger containing tertiary amine functions SAC = strong acidic cation exchanger containing sulfonic functions WAC = weak acidic cation exchanger containing carboxylic functions dso = sizt of 50% micro- or macropores na = no data presented S=specific surface area fFo = specific pore volume. 

In Table 9.9-1 both the dry and the wet capacity for some ion exchange resins are given. As can be seen there are no dramatic differences of the capacities dry for strongly or weakly acidic cation resins on the one hand and strongly or weakly basic anion resins on the other hand. The exact capacity is a function of maity parameters (cross-linking, homogeneous gel or macropore stracture, macroreticu-larity) and has to be measured for any resin. As a rule a variety of ions with the concentration in equiv./dm of the species i is present in a solution to be treated by ion exchange, for instance, the cations Na, , N7/4,, ... 

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