Cationic resins

Eig. 5. Pressure drop as affected by resin type, flow rate, and temperature, where A, B, and C, correspond respectively to acryUc strong base anion exchanger (Amberlite IRA-458), styrenic strong base anion exchanger (Amberlite IRA-402), and styrenic strong acid cation exchanger (Amberlite IR-120), all at 4°C. D represents styrenic strong acid cation resin (Amberlite IR-120) at 50°C (14). To convert kg/(cm -m) to lb/(in. -ft), multiply by 4.33 to convert... 

Combinations of anionic and cationic resins are used. Some of the eady systems involved the use of a cationic wet-strength resin with an anionic dry-strength additive to provide both increased wet and dry strength (63). Combinations of anionic and cationic dry-strength additives also are used to provide strength effects which cannot be achieved by using either polymer alone (64). The ratio of the two polymers must be optimized to achieve maximum performance (see Acrylamide polymers). 

Demineraliza tion of water is the removal of essentially all inorganic salts by ion exchange. In this process, strong acid cation resin in the hydrogen form converts dissolved salts into their corresponding acids, and strong base anion resin in the hydroxide form removes these acids. Demineralization produces water similar in quaHty to distillation at a lower cost for most fresh waters. 

These resins are referred to as cationic resins . Paper with improved wet strength may be obtained by adding an ionic resin at the beater stage of a papermaking operation. For the best results a high molecular weight resin is required. 

Strong Acid Cation Resin Charged with H ... 

Variances in resin performance and capacities can be expected from normal annual attrition rates of ion-exchange resins. Typical attrition losses that can be expected include (1) Strong cation resin 3 percent per year for three years or 1,000,000 gals/ cu.ft (2) Strong anion resin 25 percent per year for two years or 1,000,000 gals/ cu.ft (3) Weak cation/anion 10 percent per year for two years or 750,000 gals/ cu. ft. A steady falloff of resin-exchange capacity is a matter of concern to the operator and is due to several conditions ... 

Backwash Cycle - Prior to regeneration, the cation and the anion resins are separated by backwashing at a flow rate of 3.0 to 3.5 gpm/ft. The separation occurs because of the difference in the density of the two types of resin. The cation resin, being heavier, settles on the bottom, while the anion resin, being lighter, settles on top of the cation resin. After backwashing, the bed is allowed to settle down for 5 to 10 minutes and two clearly distinct layers are formed. After separation, the two resins are independently regenerated. 

Table 3. Chelating Cation Resin Selectivities for Metal Ions.

The resin bed is brought in con- tact with the regenerant solution. In the case of the cation resin, acid elutes the collected ions and converts the bed to the hydrogen form. A slow water rinse then removes any residual acid. 

In this synthesis, the cationic resin Amberlite IR 122 was used as catalyst. The product was isolated by high vacuum distillation at 175°, a temperature which may have also depolymerized some of the open-chained oligomers present. ... 

Polymeric resins such as poly(acrylamide-acrylic acid) [24,25] [cationic resin, pAM-AA], poly(acrylic acid-diallylethylamine-HCl) [20] [amphoteric resin, pAA-DAEA-HCl], and poly(acrylamide-acrylic acid-di-allylamine-HCl [26] [amphoteric resin. pAM-AA-DAA-HCl] and poly(acrylamide-acrylic acid-diallylethylam-ine-HCl) [26] [amphoteric resin, pAM-AA-DAEA-HCl] were also used in water treatment. 

The extensive possibilities of the practical application of synthesis, and the study of the properties of ion-ex-change resins have aroused widespread interest in chemistry. This chapter discusses some theoretical problems with cationic resins as catalysts in hydrolysis reactions. New types of cationic resins have been examined and some important generalizations on ion-exchange reactions have been formulated. 

In recent years, the rate of information available on the use of ion-exchange resins as reaction catalysts has increased, and the practical application of ion-exchanger catalysis in the field of chemistry has been widely developed. Ion-exchangers are already used in more than twenty types of different chemical reactions. Some of the significant examples of the applications of ion-exchange catalysis are in hydration [1,2], dehydration [3,4], esterification [5,6], alkylation [7], condensation [8-11], and polymerization, and isomerization reactions [12-14]. Cationic resins in form, also used as catalysts in the hydrolysis reactions, and the literature on hydrolysis itself is quite extensive [15-28], Several types of ion exchange catalysts have been used in the hydrolysis of different compounds. Some of these are given in Table 1. 

New Macroreticular Cationic Resins from Natural Products... 

The capacity of the sulfonated cationic resin is decreased with increases in the paraformaldehyde content. 

Figure 4 Effect of formaldehyde content on the capacity of cationic resins.

Table 10 Capacities, Average Swelling Percentages, and Absolute Densities for Sulfonated Corncob Cationic Resins...

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