Sulfonic acid esters, hydrolysis

Solid esters are easily crystallisable materials. It is important to note that esters of alcohols must be recrystallised either from non-hydroxylic solvents (e.g. toluene) or from the alcohol from which the ester is derived. Thus methyl esters should be crystallised from methanol or methanol/toluene, but not from ethanol, n-butanol or other alcohols, in order to avoid alcohol exchange and contamination of the ester with a second ester. Useful solvents for crystallisation are the corresponding alcohols or aqueous alcohols, toluene, toluene/petroleum ether, and chloroform (ethanol-free)/toluene. Esters of carboxylic acids derived from phenols are more difficult to hydrolyse and exchange, hence any alcoholic solvent can be used freely. Sulfonic acid esters of phenols are even more resistant to hydrolysis they can safely be crystallised not only from the above solvents but also from acetic acid, aqueous acetic acid or boiling n-butanol. Note that sulfonic esters of lower alcohols, e.g. methanol, are good alkylating agents. 

It has to be pointed out that, with a few exceptions, the acceleration by polyelectrolytes was associated with decreases and Table IV gives the thermodynamic parameters for the aquation reactions of Co(NH3)5Br induced by Ag". Similar decreases in and AS were found for various reactions the Hg -induced aquation of Co(NH3)5Br , the SpjAr reaction of dinitrochlorobenzoic acid with OH [51], the hydrolysis of 2,4-dinitrophenyl phosphates [reaction (E)] [33], the outer-sphere electron-transfers between Co-complexes [Co(NH3)5N3, Co(NH3)5Br , Co(en)2Cl2 ] and Ru(NH3)6 or [8, 20] [en ethylenediamine], the polyvinyl-imidazole-accelerated solvolysis of p-nitrophenylacetate [52], the coupling reactions of dinitrofluorobenzene with aminoacids [53], dipeptides [53] and aniline [54], the lignin sulfonic acid-accelerated hydrolysis of methyl acetate [55], and the hydrolysis of nitrophenyl esters [37]. The opposite tendency (acceleration caused by increases... 

Kiermeier and co-workers [23] and Wildbrett and co-workers [24] have developed schemes for the measurement of the extractability of monomeric phthalate ester and C10/C20 alkane phenyl sulfonates from polyvinyl chloride (PVC) containers into milk. After leaving raw milk at 38 "C for 4 hours in contact with PVC tubing containing bis(2-ethylhexyl) phthalate or phenol or cresol alkanesulfonate, the respective plasticiser was determined. Schemes are described for separation and hydrolysis of the phthalic acid ester, with spectrophotometric determination of the liberated phthalic acid at 284 nm, and for the separation and saponification of the alkane sulfonic acid ester and for spectrophotometric determination at 470 nm, of the liberated phenol or cresol after coupling with diazotised nitroaniline and addition of sodium carbonate solution. 

Two important widely used sulfonic acids are known as TwitcheU s reagents, or as in Russia, the Petrov catalysts. These reagents are based on benzene or naphthalene ( ) and (12), [3055-92-3] and [82415-39-2] respectively. The materials are typically made by the coupling of an unsaturated fatty acid with benzene or naphthalene in the presence of concentrated sulfuric acid (128). These sulfonic acids have been used extensively in the hydrolysis of fats and oils, such as beef tallow (129), coconut oil (130,131), fatty methyl esters (132), and various other fats and oils (133—135). TwitcheU reagents have also found use as acidic esterification catalysts (136) and dispersing agents (137). 

Hydrolysis of esters is speeded up by both acids and bases. Soluble aflcylaiyl sulfonic acids or sulfonated ion exchange resins are suitable. 

Neutralization of the sulfonation product from a-olefins is more complex than neutralization of the corresponding products of alkylbenzenes. This is because the S03-a-olefin acid product contains about 50% free sulfonic acid, the rest being C(l,3) and D(l,4) sultones, assuming that with acid aging the 0(1,2) sultones have disappeared. In the case of a-olefins an excess of caustic (1.5-2.0% excess) must be added to neutralize both the sulfonic acid initially present and that formed on subsequent hydrolysis of the C(l,3) and D(l,4) sultones. The sultones (ring-structured esters) cannot be converted to their proper salts by a simple neutralization but need a hydrolysis step. 

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. 

Phosphoric and polyphosphoric acid esters Perfluorinated anionics Sulfonic acid salts Strong surface tension reducers Good oil in water emulsifiers Soluble in polar organics Resistant to biodegradation High chemical stability Resistant to acid and alkaline hydrolysis... 

Prior to imide formation, the imide-aryl ether ketimine copolymers were converted to the imide-aryl ether ketone analogue by hydrolysis of the ketimine moiety with para-toluene sulfonic acid hydrate (PTS) according to a literature procedure [51,52,57-59]. The copolymers were dissolved in NMP and heated to 50 °C and subjected to excess PTS for 8 h. The reaction mixtures were isolated in excess water and then rinsed with methanol and dried in a vacuum oven to afford the amic ester-aryl ether ether ketone copolymer, 2e (Scheme 8.)... 

Hydrolysis can detoxify a wide range of aliphatic and aromatic organics such as esters, ethers, carbohydrates, sulfonic acids, halogen compounds, phosphates, and nitriles. It can be conducted in simple equipment (in batches in open tanks) or in more complicated equipment (continuous flow in large towers). However, a potential disadvantage is the possibility of forming undesirable reaction products. This possibility must be evaluated in bench- and pilot-scale tests before hydrolysis is implemented. 

Hydrolysis of phenolic esters 0-32 Cleavage of phenolic ethers with sulfonic acids... 

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