Alkylation sulphonate

Boilers and steam systems Steel steam lines can be inhibited by the use of a volatile amine-based inhibitor such as ammonia, morpholine or cyclohexylamine introduced with the feedwater. It passes through the boiler and into the steam system, where it neutralizes the acidic conditions in pipework. The inhibitor is chemically consumed and lost by physical means. Film-forming inhibitors such as heterocyclic amines and alkyl sulphonates must be present at levels sufficient to cover the entire steel surface, otherwise localized corrosion will occur on the bare steel. Inhibitor selection must take into account the presence of other materials in the system. Some amine products cause corrosion of copper. If copper is present and at risk of corrosion it can be inhibited by the addition of benzotriazole or tolutriazole at a level appropriate to the system (see also Section 53.3.2). 

Examples of liquid cation exchangers are alkyl and dialkyl phosphoric acids, alkyl sulphonic acids and carboxylic acids, although only two appear to have been used to any extent, viz. di-(2-ethylhexyl)phosphoric(V) acid and dinonylnaphthalene sulphonic acid. 

Alkylation with alkyl sulphonates in organic solvents... 

The two principal categories of compounds studied have been diaryl or aryl alkyl sulphones (not dialkyl sulphones, which are polarographically not reducible) and S-dioxides of certain heterocyclic compounds, such as thiophene (also benzo- and dibenzothiophenes) and phenothiazines. The first named have half-wave potentials in the region of — 2.0 V, the thiophene dioxides near — 1.0 V. Some examples of each category may be given. 

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). 

Trost published a desulphonylation procedure for aryl alkyl sulphones using an excess of sodium amalgam in buffered ethanol126 (equation 52). Trost claimed that this is superior to earlier reactions using sodium amalgam in ethanol because of a couple of factors the use of the acid phosphate buffer to prevent formation of significant amounts of sodium methoxide is particularly important, since this can cause isomerizations in base-sensitive substrates, and the temperature should be kept low, but optimized for each substrate. 

The use of chlorine as an oxidizing agent for the conversion of sulphoxides into sulphones is completely unsuccessful under anhydrous conditions. In aqueous solutions, the sulphone is formed but this is usually part of a complex mixture of chlorinated sulphoxides, chlorinated sulphones and sulphonyl chlorides89, so that the reaction is usually not very useful as a preparative method for alkyl sulphones. Dimethyl sulphone has however been obtained in 70% yield in one isolated case90. In methanol solution dibenzyl sulphoxide is cleanly oxidized to dibenzyl sulphone and benzyl sulphonyl chloride in reasonable overall yield91. 

J. Simonet, unpublished observations concerning many aryl/alkyl sulphones provided by Prof. Marc Julia, Paris. 

Arylsulphonyl radicals 879 Arylthiomethyl sulphoxides, reactions of 331 / -Arylthiovinyl sulphoxides, synthesis of 345 Aryl unsaturated alkyl sulphones, mass spectra of 137-143... 

Sulphones (coni.) allenic - see Allenic sulphones allyl - see Allyl sulphones aryl unsaturated alkyl - see Aryl unsaturated alkyl sulphones aryl vinyl - see Aryl vinyl sulphones as radiolytic products 907 bicyclic - see Bicyclic sulphones bis(/ -hydroxyalkyl) - see Bis... 

These results were significantly improved by the same authors using the well-defined pre-catalyst 16 (PEPPSl-lPr), that is able to promote the coupling of alkyl halides, aryl halides or alkyl sulphonates with alkylzinc chlorides or bromides [83,84]. 

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 ... 

Figure 23.2 Effect of pH on tantalite and columbite flotation using sodium alkyl sulphonate as collector.

Sodium alkyl sulphonate is also a collector for tantalite and columbite at a pH below 3.0 (Figure 23.2). At a pH above 3.0, flotation recovery of tantalite and columbite decreased rapidly. This collector was not selective towards gangue minerals, such as tourmaline and garnet. 

In a quite analogous way ethylene reacts with nitric-sulphuric acid, nitroethyl nitrate (p. 164) being produced. How are alkyl sulphonic... 

Method A TBA-Br (3.22 g, 10 mmol) in aqueous NaOH (2M, 5 ml) is added dropwise to the methylenesulphone (10 mmol) in CHCI3 (17 ml) and the mixture is stirred for 30 min at 20°C. The organic phase is separated, dried (MgS04), and added to the alkylating agent (10 mmol) in CHCl, (5 ml). The mixture is allowed to stand at room temperature for 40 min and is then evaporated under reduced pressure. The residue is extracted with Et20 (4 x 20 ml) and the extracts are evaporated to yield alkylated sulphone. 

Most aryl alkyl sulphones react with electron-deficient alkenes in the expected manner [e.g. 4-8] and a-(arenesulphonyl)acetic esters undergo a catalysed one-pot double Michael addition with Michael acceptors (Scheme 6.24) [8], The two Michael acceptors can be either identical or different. 

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