Alkyl sulphonic salts

Another marked physical difference between sulphides and sulphoxides (or sulphones) is that sulphoxides (and lower alkyl sulphones) are hygroscopic and dissolve quite readily in water or protic solvents such as alcohols, and even more so lower alkyl or alkyl aryl sulphoxides are almost freely miscible with water. This can be accounted for by the formation of the strong hydrogen bond between the S—O bond in the sulphoxides and water molecules. Moreover, lower alkyl sulphoxides and sulphones such as dimethyl sulphoxide (DMSO) or sulpholene can dissolve a number of metallic salts, especially those of alkali and alkaline earth metals, and hence these compounds have been widely utilized as versatile and convenient solvents in modern organic chemistry26 (Table 3). 

Typical ion-pairing reagents are, for cations, alkyl sulphonic acids, eg pentane, hexane, heptane or octane sulphonic acid, and for anions, tetrabutylammonium or dibutylamine ammonium salts. In ion-pair chromatography the retention of solutes can be controlled in a number of ways ... 

The salinity effect of different salts, particularly divalent cation salts, is expressed through the term bS in the correlation for non-ionic surfactants of the polyethoxylated phenol or alcohol type. No information is available yet on the salinity effect on other non-ionics such as alkyl-polyglucosides. The salinity effect on ionic surfactant systems is a more complex issue because the surfactant itself is also a (more or less) dissociated electrolyte. Its degree of dissociation is paramount as far as its hydrophilicity is concerned. For instance sodium salts of alkyl sulphonic acids are essentially completely dissociated, hence they act as the sulphonate ion, and it is essentially the same with the salt of potassium or ammonium. The presence of multivalent anions produces an interference with the monovalent anionic surfactant ion, such as an alkyl benzene sulphonate, but it is essentially an ideal mixing rule. 

Oxidation of methyl perfluoroalkyl sulphones with refluxing aqueous potassium permanganate produced the perfluorinated alkyl sulphonic acid in 85% yield as the potassium salt (equation 45). Cyclic sulphones containing a,a -chlorine substituents are also susceptible to easy hydrolysis yielding sulphonic acid salts in good yields (equation 46)256. The above-described behaviour should be contrasted with simple dialkyl... 

Similar differences in the surfactant nature of soluble and insoluble species can be found in studies of foam stability. Broadly speaking, insoluble or solid-type surfactants do not efficiently stabilise foams (Garrett, 1967b). On the other hand, water-soluble surfactants such as the alkyl sulphonates, phosphates and tri-alkyl ammonium salts, all common detergents, form prolific foams. Wilson (1959) noted the accumulation of albuminoid-N compoimds in coastal sea foams, while Southward (1953), who found a variety of planktonic and benthic oi anisms in such foams, concluded that proteins were probably responsible for the foam stability. Wilson and Collier (1972) have observed the production of such foam-stabilising events in appreciable quantities by various marine organisms such as diatoms. 

Fig. 3. Influence of the temperature on the solubility of Na-salts of higher alkyl sulphonates (according to Tartar and Wright, 1939).

Anionic anti-static agents are usually alkali salts of alkyl sulphonic and sometimes phosphonic or carboxylic acids. Sodium alkyl sulphonates are recommended for styrenics. 

Protection and Deprotection.—N-Protected a-amino-acids are readily esterified by methanol or ethanol in 60—80% yield after reaction with an enamine (e.g. from isobutyraldehyde and piperidine) and t-butyl isocyanate. Such amino-acids can also be esterified efficiently with alkyl halides under phase-transfer conditions with no racemization. Direct esterification of a-amino-acids with ethyl toluene-p-sulphonate in boiling ethanol gives a-amino-acid ethyl esters in 80—90% yield as the sulphonate salts. The protection of acid functions by formation of the 2-chloro-(or bromo-)ethyl esters has been discussed. These derivatives survive exposure to both moderately acidic and basic conditions and are removable by conversion into the iodoethyl analogues followed by zinc reduction. Alternatively, they may be converted into hydrophilic ammonium or phosphonium salts which exhibit enhanced acid stability but which are cleaved by very dilute base. Yet another method for the removal of such groups using supernucleophilic Co phthalocyanin anions has been reviewed. Further routes to 2,2,2-trichloroethyl esters have been described, one of which employs an activated ester intermediate and is suited to acid-labile substrates. 

Figure 2.13 Phase diagrams for ternary systems containing an alkyl sulphate, alkyl sulphonate, a primary or a quaternary alkyl ammonium salt, water and an alcohol.

O Samul 05 Amine salt of an alkyl sulphonic acid 4.03 3.33 2.67... 

Alkyl sulphonic acid sodium salts 1195-1175 8.37-8.51 vs asym SO3 str... 

Preparation of Thiocyanates.—Variations of standard methods for the synthesis of thiocyanates are illustrated in the addition of alkoxy- and thiocyanato-groups to alkenes using KSCN, CuClj (or other Cu salt), and an alcohol as solvent, to give a-alkoxy-alkyl thiocyanates and in the addition of pseudohalogens CISCN or (SCN)a to chalcones. A sulphonylthiocyanate RSOaSCN, prepared from (SCN)a and a sodium sulphinate, adds similarly to alkenes to give a-thio-cyanato-alkyl sulphones. > Aryl selenocyanates may be prepared from the... 

Secondly, ionic analytes of opposite charge can be immobilized and pre-concentrated by imi pairing with highly lipophilic and voluminous moieties, such as anion-attracting tetraalkyl ammonium salts (e.g. CTAB, see Table 5.2 and references (100, 104, 105)) or the long-chain alkyl-sulphonic acids for coupling with cations. Also this type of pre-concentration can be accomplished in situ and due to this, it can be classified as a particular case of the previous one. 

Oxidation of either alkyl or aryl sulphoxides to sulphones in 65-90% yields may be accomplished by treatment with a nitronium salt . In the case of aryl sulphoxides no nitration is observed (which is in contrast to the results of nitric acid oxidation). The reaction was shown to proceed through intermediate nitratosulphonium and nitritosulph-oxonium ions, as depicted in equation (7), which were studied by nmr spectroscopy. 

To add to the silver salt (Eq. 19) and peroxymercuration (Eq. 34-36) methods of preparing dialkyl peroxides, a third mild alkylation procedure has been developed that involves the use of alkyl trifluoromethane sulphonates (triflates)55). The peroxide transfer reaction between bistributyltin peroxide and the bistriflate 58 of cis-1,3-cyclopentanediol provided one of the first syntheses of 2,3-dioxabicyclo[2.2.1]heptane 9 (Eq. 44, H for D Tf = 02SCF3)56). Because of the sensitivity of 9, it was necessary to carry out the reaction in vacuo with rapid transfer of the volatile products to a cold trap to avoid decomposition a yield of 22% was achieved. 

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