Sulfonic acids from sulfonate esters

If a waste sulfuric acid regeneration plant is not available, eg, as part of a joint acrylate—methacrylate manufacturing complex, the preferred catalyst for esterification is a sulfonic acid type ion-exchange resin. In this case the residue from the ester reactor bleed stripper can be disposed of by combustion to recover energy value as steam. 

Phthalocyanine sulfonic acids, which can be used as direct cotton dyes (1), are obtained by heating the metal phthalocyanines in oleum. One to four sulfo groups can be introduced in the 4-position by varying concentration, temperature, and reaction time (103). Sulfonyl chlorides, which are important intermediates, can be prepared from chlorosulfonic acid and phthalocyanines (104). The positions of the sulfonyl chloride groups are the same as those of the sulfonic acids (103). Other derivatives, eg, chlormethylphthalocyanines (105—107), / /f-butyl (108—111), amino (112), ethers (109,110,113—116), thioethers (117,118), carboxyl acids (119—122), esters (123), cyanides (112,124—127), and nitrocompounds (126), can be synthesized. 

Fig. 1. Sulfonated and sulfated acid products viscosities after 98% conversions at varying temperatures where the vertical line indicates the maximum temperature for batch sulfonation using SO to minimi2e color deterioration lines A—C represent branched C 2 alkyl ben2ene (BAB) sulfonic acid from SO, oleum (settied), and oleum (whole mixture), respectively lines D and E, lauryl alcohol 3-ethoxylate sulfuric ester (SO ) and lauryl alcohol sulfuric ester...

Fatty JicidFster Sulfonates. Fatty acid ester sulfonates (FAES) are generally produced from methyl esters, ie, methyl ester sulfonate (MES) and prepared via sulfonation, followed by bleaching and neutralization, in a relatively difficult and complex process ... 

Ethers. In the presence of anhydrous agents such as ferric chloride (88), hydrogen bromide, and acid chlorides, ethers react to form esters (see Ethers). Esters can also be prepared from ethers by an oxidative process (89). With mixed sulfonic—carboxyhc anhydrides, ethers are converted to a mixture of the corresponding carboxylate and sulfonate esters (90) ... 

Acidic Hydrolysis. Hydrolysis of esters by use of water and a mineral acid leads to an equiUbrium mixture of ester, alcohol, and free carboxyHc acid. Complete reaction can only be achieved by removal of alcohol or acid from the equiUbrium. Because esters have poor solubiUty in water, the reaction rate in dilute acids is fairly low. Therefore, emulsifiers such as sulfonated oleic acid or sulfonated aromatic compounds (TwitcheU reagent) are added to facihtate the reaction. 

Polymer films can be made antistatic with a-sulfonated fatty acid salts and esters [94]. For example, an antistatic additive for polypropylene manufacture can be prepared from potassium methyl a-sulfopalmitate, styrene oligomer, and 2-propanol [95]. The treatment of synthetic fibers and fabrics with a-sulfo-... 

Oae found that for both base- and acid-catalyzed hydrolysis of phenyl benzenesul-fonate, there was no incorporation of 0 from solvent into the sulfonate ester after partial hydrolysis. This was interpreted as ruling out a stepwise mechanism, but in fact it could be stepwise with slow pseudorotation. In fact this nonexchange can be explained by Westheimer s rules for pseudorotation, assuming the same rules apply to pentacoordinate sulfur. For the acid-catalyzed reaction, the likely intermediate would be 8 for which pseudorotation would be disfavored because it would put a carbon at an apical position. Further protonation to the cationic intermediate is unlikely even in lOM HCl (the medium for Oae s experiments) because of the high acidity of this species a Branch and Calvin calculation (See Appendix), supplemented by allowance for the effect of the phenyl groups (taken as the difference in between sulfuric acid and benzenesulfonic acid ), leads to a pA, of -7 for the first pisTa of this cation about -2 for the second p/sTa. and about 3 for the third Thus, protonation by aqueous HCl to give the neutral intermediate is likely but further protonation to give cation 9 would be very unlikely. 

Carboxylate anions derived from somewhat stronger acids, such as p-nilrobcnzoic acid and chloroacetic acid, seem to be particularly useful in this Mitsunobu inversion reaction.53 Inversion can also be carried out on sulfonate esters using cesium carboxy-lates and DMAP as a catalyst in toluene.54 The effect of the DMAP seems to involve complexation and solubilization of the cesium salts. 

Apart from aryl esters and amides of carboxylic acids, aryl carbonates, and carbamates, other types of organic compound have been reported to undergo PFR. They include oxalates, formiates, sulfonates, sulfonamides, thioesters, selenoesters, and telluroesters. 

Nucleophilic displacement using [ F] fluoride works well in aUphatic systems where reactive haUdes or sulfonates esters can undergo substitution at unhindered sites. In order to introduce a F fluorine atom in a secondary or tertiary position, a two steps strategy was developed. It involves a F-bromofluorination of alkenes, followed by reductive debromination (n-BujSnH, AIBN). [ F]BrF is usually generated in situ from [ F]potassium fluoride and l,3-dibromo-5,5-dimethylhydantoin (DBH) in sulfuric acid. This methodology was successfully applied to label steroids at the 11 and 6a positions [245] (Scheme 60) and to prepare [ F]fluorocyclohexanes [246]. 

Formally, the synthetic route outlined in Scheme 6 constitutes the preparation of a new ring system from another. Nucleophilic attack of amine on the sulfonate ester, a particularly good leaving group, leads to monocyclic compound 67. Conversion of the sulfonic acid moiety into a sulfonyl chloride by POCI3 then yields the sulfonyl chloride siVu, which then undergoes nucleophilic attack by the pendant amine resulting in the chiral sultam 68. 

Sulfonic acids, R(Ar)S03H, form derivatives similar to those of carboxylic acids (see Table 16-3). These are sulfonyl chlorides, sulfonates (esters), and sulfonamides. The transsulfonylation reactions are similar to the transacylation reactions, except that the ester and amide cannot be made directly from the acid. See Problem 13.17 for preparation of sulfonyl chlorides and esters and Problem 13.18 for use of sulfonate esters as substrates in S l and S,42 reactions. 

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