Sultone complexes

Reactions between SO3 and a variety of complexes " " containing the functionalized alkyl —CH2—CsC—R yield metal-sultone complexes. 

AOS is a complex mixture of different chemical species. A typical product composition is as follows [1-7] sodium alkenesulfonate (60-70%) sodium hydroxyalkanesulfonate (30%) sodium disulfonate (0-10%) 6- or 1, 4-sultone (50 ppm) unsulfonated matter (less than 2%) and inorganic salt (mainly sodium sulfate, less than 2.5%). AOS can therefore be regarded as a surfactant system in contrast with other common surfactants such as alkyl sulfates, alkyle-thoxy sulfates, alkanesulfonates, and alkylbenzenesulfonates, which consist of mixtures of their isomers and/or homologs. 

Although the quantitative determination of 1,4-sultones seemed possible by GLC, this method was not adopted by them because technical batches of C)2-C18 AOS gave very complex chromatograms. This is due to the fact that ... 

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. 

The mechanism and synthetic scope of reactions of monohaptopropargyl-iron complexes has been described earlier (see Schemes 30-33 in Section IV,A,2). By using sulfur dioxide and sulfur trioxide as electrophilic reagents, it is possible to synthesize metal-containing heterocycles in the reduced 1,2-oxathiole category (sultines and sultones) (Scheme 119).182-184 An... 

The dioxane-sulfur trioxide complex reacts with 2,3-dimethylbutadiene to give the sultone... 

The different stereochemical outcome observed in the opening of sultones by the action of dimethyl sulfide and by that of Me2S-SC>3 complex with the conjugated alkadienes has been considered as evidence against the intermediate formation of the sultones in the... 

Alpha Olefin Sulfonates. The direct reaction of alpha-olefins with a strong sulfonating agent yields a mixture of alkane sulfonates, hydroxy-lalkane sulfonates, and disulfonated products. These are known commercially as a-olefin sulfonates (AOS). AOS manufacture is generally more complex than ABS because the initial reaction product is a mixture of sultones as shown in Fig. 36.33. 

Aliphatic y-sultones and 8-sultones may be synthesised by the sulfonation of alkenes by reaction with the sulfur trioxide-dioxan complex or gaseous sulfur trioxide (Scheme 66). 

The formation of the sultone (160) probably involves addition of the complex across the alkene double bond, a 1,2-hydride shift and an intramolecular nucleophilic substitution reaction. The sultone (161) is formed by addition of sulfur trioxide to give the unstable p-sultone which rearranges to the more stable y-isomer (161). Another useful route to sultones is by metallation of alkanesulfonate esters for example, butane-1,3-dimethylsulfonate (162), prepared from butanel,3-diol, yields the 8-sultone, namely 6-methyl-l,2-oxathiin-2,2-dioxide (163) (Scheme 67). 

The most common method of sulphonate ester production via carbon-sulphur(VI) bond formation is the direct reaction of alkenes with either sulphur trioxide or sulphur trioxide adducts. The product formed in these reactions is usually a four-membered sultone (cyclic sulphonate ester) although in some cases six-membered sultones or more complex products are formed. Sulphonic acids (or their salts) are also produced and this has been covered in an earlier section of the present chapter. 

A variety of sulphonation agents has been used in the preparation of sultones from alkenes. These include liquid-phase sulphur trioxide, Lewis base-complexed sulphur trioxide such as S03-dioxane29 and S03-pyridine25, gaseous sulphur trioxide30 and chemisorbed sulphur trioxide31. Examples are shown in equation 7. More recently the reagent acetyl sulphate has been used in the sulphonation of ethylidenenorbornane to produce the y-sultone 732. The reaction pathway proposed for the formation of 7... 

The yields of y- and <5-sultones obtained from the sulphonation of alkenes depend largely on the nature of the sulphonation reagent and reaction temperature. The sulphur trioxide-Lewis base complexes effect less charring than uncomplexed sulphur trioxide, but the lower reactivity of the former tends to lead to lower yields of sultones under the... 

Generally, sulfur trioxide reacts with hydrocarbon olefins quite vigorously and has to be either diluted or used in complexes with pyridine or dioxane to moderate its reactivity. The corresponding cycloadducts, p-sultones, easily undergo ring opening and have not yet been isolated. In sharp contrast, fluorinated p-sultones are relatively stable materials and over 50 compounds of this type have been prepared and isolated. Synthesis and chemistry of this class of heterocycles is well documented and has been previously reviewed. ... 

The mesylate-tosylate in the framework of the pyranose derivative reacted with lithium acetylide-ethylenediamine complex to give the seven-membered sultone (13) in 98% yield, as a result of displacement of a tosylate coupled with deprotonation at the mesylate producing a nucleophile and then ring formation (Scheme 6) <81CJC260>. 

The reaction of sulfur trioxide with of-olefines in molecular ratios gives rise to two main products, i.e. isomeric alkenesulfonates and sultones. The 1,2-sulfone is produced first, followed by transformation into the 1,3- and 1,4-sultones. Hydrolysis then leads to hydrox-yalkanesulfonates. The overall synthesis is a four-stage process of sulfonation, transformation, neutralization and hydrolysis. The complex mixture of isomeric alkenesulfonates and hydroxyalkanesulfonates is known under the collective term of of-olefinesulphonates , an anionic surfactant that is itself a blend of different... 

Sulphonation of benzocyclobutene with sulphur trioxide complexes leads not only to benzocyclobutene-3- and -4-sulphonic acids but also to cleavage of the four-membered ring with formation of the sultone of 2-(o-sulphophenyl)ethanol in an ipso sulphonation reaction... 

Reaction of an alkene with an excess of SO3 gives a cyclic sulfonate-sulfate anhydride, also referred to as carbyl sulfate or pyrosulfate (eq 5). This carbyl sulfate is formed by a slow insertion of SO3 into the intermediate -sultone. The complex of sulfur trioxIde with dimethyl sulfide reacts with alkenes and alkynes to afford sulfobetaines in good yields (eq 6). These sulfobetaines are produced by nucleophilic attack of the dimethyl sulfide on the initially formed -sultones. 

Olefin sulphonates are complex mixtures as a result of migration of the double bond during sulphonation and hydration across the double bond, resulting in the formation of hydroxyalkane sulphonates and sultones (internal esters) and the so-called disulphonic acids (actually sulphatosul-phonic acids). These are more fully discussed in chapter 5. 

---