Alkylation, sulphonates, phosphonates

Not unexpectedly, marine crankcase oils are sometimes contaminated with water, which is normally removed by the lubricating oil centrifuge. To assist further in protecting against rusting, inhibitors such as alkyl sulphonates, phosphonates, amines and alkyl succinic acids/esters can be added. They work by forming a hydrophobic film on the metal surface but must be selected with due regard to the other additives present. 

Scheme 8 Direct alkylation via sulphonates, phosphonates and phosphinates...

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

Strongly polar and ionic surface active substances such as alkyl sulphates and alkyl sulphonates, phosphates and phosphonates, can also be fractionated thin-layer chromatographically [33, 121]. Mixtures of these detergents have been separated on sihca gel G containing 10% ammonium sulphate, using the mixtures of chloroform-methanol and sulphuric acid given in Table 68 [121]. 

In the Michaelis reaction (which usually gives lower yields than the corresponding Arbusov reaction), a metal dialkylphosphite (dialkylphosphonate - see below) is reacted with an alkyl halide to give a dialkyl ester of an alkyl phosphonate (6.272). Alkyl p-toluene sulphonates or dialkyl sulphates may be used in place of alkyl halides. Esters of unsaturated phosphonic acids, containing OH and CO groups can be obtained from an unsaturated aldehyde and a dialkyl phosphite (6.273). 

An interesting finding in this area is that no added catalyst is necessary in the reactions of equation (4). The assumption made was that phosphonate systems could, like their phosphonium ion counterparts, act as their own phase-transfer catalysts, and this is borne out by the use of a-phosphoryl sulphoxides and sulphones (13) and related compounds as the mediators of some two-phase car-banion alkylations. 

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