Sulfonic acid exchange resin

An exchange resin sulfonic acid has also been used as catalyst in a very elegant ketone condensation Lorette948 obtained mesityl oxide in almost 80% yield by passing acetone vapors over Dowex 50 ethyl methyl ketone gives a mixture of the two isomers (5-methyl-4-hepten-3-one and 3,4-dimethyl-... 

Amberlite IR-120 (cation exchange resin sulfonic acid type) at 160° for 2-3 h... 

Ion exchange resins based on poly(styrene-divinylbenzene) backbones display mixed mode retention mechanisms. The ion exchange functionality (sulfonic acid or carboxylic acid for cation exchangers and quartemary or primary, secondary, or tertiary amines for anion exchangers) contributes to the ionic mechanism and the backbone polymer to hydrophobic retention. This is exemplified... 

A palladium(II)-exchanged polystyrene sulfonic acid resin (Dowex 50W, H form) catalyzes the oxidation of 2-methylnaphthalene with 60% aqueous H2O2 (reaction 27), affording 2-methyl-l,4-naphthoqu1none (menadione) in 55-60% yield at 90-97% conversion. 3 Menadione is a commercially important vitamin K intermediate and these results compare favourably with those obtained in existing industrial processes that employ stoichiometric quantities of chromium trioxide in sulfuric acid. 

Ion exchange resins (methacrylic acid, sulfonated polystyrene/divinylbenzene) Polyacrylic acid (Carbopol) Poly(MMA/MAA)... 

Not only do these acids present an economic advantage over conventional acid technology, but there are also frequent selectivity eidiancements and changes in reactivity associated with the use of these heterogeneous catalysts. A number of different types of solid acids have been involved in synthetically useful reactions. They range from the hydrogen forms of various ion exchange resins and the perflourinated resin sulfonic acid, Nafion-H, to the amorphous acidic oxides, silica and aluminum silicate,the crystalline zeolites > and the natural clays. -9... 

Comparison data were presented, that demonstrate the use of the polysiloxane material as an advantageous substitute for organic cation exchange resins, sulfuric acid, p-toluene sulfonic acid and acidic zeolites. It is demonstrated, that materials like 1 and 2 are cost-efficient and reliable catalysts in esterification, alkylation, and condensation, whereas use of the bifunctional catalyst 3 gives excellent conversions in hydrogenolysis reactions in general. 

These resins contain acidic functional groups added to the aromatic ring of the resin. The strong-acid cation exchangers have sulfonic acid groups, —SO3H, which... 

A.8 Ion Exchange Resin Superacids. Nafion-H.- Olah, the founder of superacid chemistry classified perfluorinated resin-sulfonic acid - Mafion-H into the family of superacids. It is... 

As just mentioned, strong or weak acidic ion exchangers contain sulfonic acid or carboxylic acid groups in the H or alkali metal salt form and consist of 1,4-divinylbenzene cross-linked polyst3Tene or poly(acrylic acid) as shown in formulae 7a and 7b. Another example is the sulfonated phenol-formaldehyde condensation polymer 8. The preparation of ion-exchange resins and the determination of their capacities are described in Section 5.4, Experiments 5-1 and 5-2. 

The sulfuric acid used as a catalysf in this reaction may be replaced with Dowex 50WX8-100 cationic exchange resin (sulfonate groups). 

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