Sulphone group

Once the presence of a sulphonate group has been estabhshed (and, if possible, the phenol isolated), the compound may be characterised by the preparation of a derivative. It must be remembered that both sulphoxides RSOR and sulpJiones RSOjR yield sulphur dioxide on fusion with caustic alkali and acidification. 

In some situations the nitro group behaves as if it exerted its influence mainly by the inductive process, but in nitration its behaviour seems to place it with this group of —I —M substituents. The precise way in which a sulphone group is described depends on how much weight is given to the ability of the sulphur atom to expand its octet the positive... 

The Ar and/or Ar group(s) will contain sulphone groups and if Ar = Ar then identical products may be obtained by the two routes. Polyetherification processes form the basis of current commercial polysulphone production methods. These will be discussed further below. 

The sodium salt of the cymene sulphonic acid is then fused with sodium hydroxide in the usual manner, and the hydroxyl group substituted for the sulphonic group. This gives l-methyl-3-hydroxy-4-isopropyl-benzene or thymol. 

The sulphone group does not perturb very much the hydrocarbon part of the molecules by inductive effects the charges on CH3 or CH2 groups are rather small. The S—O bond in all sulphones (except H2S02) is about as strong as in S02 itself (see the S—O BOPs in Figure 18b). 

TABLE 14. Group volumes (V in A3) and surfaces (S in A2) for fragments a to sulphur, and for sulphoxide and sulphone groups... 

Since the sulphone group contains sulphur in its highest oxidation state, specific analytical procedures based on controlled oxidation are not possible. The complete molecule can be submitted to oxidative degradation, e.g. in the elemental sulphur determination, methods for which, as stated above, will not be included here. 

The sulphoxide group is more amenable to chemical analytical methods than the sulphone group. Controlled oxidation and reduction are possible ... 

Some polarographic work has been performed on sulphones in which, evidently, other functional groups suffered reduction. Thus the vinyl group rather than the sulphone group of methyl vinyl sulphone was reduced polarographically -. The unsaturated group of a, -unsaturated sulphones was also reduced . Halogen substituents have been... 

The polyester sizes used have a much lower average molecular mass than polyester fibres. These structures (10.69) contain sulphonic acid groups and may be water-soluble or water-dispersible types. The degree of sulphonation is low [171]. If these resins are subjected to a high pH, the sulphonate groups can be hydrolysed, giving an insoluble resin that is very difficult to remove from the fibres. 

The sulphite aftertreatment is particularly important with permonosulphuric acid treatment. Evidence for the underlying mechanism is available from analysis of sulphur oxidation products formed in the various processes (Table 10.34). It is evident from these results that the concentration of RSS()5 anionic groups necessary to change the hydration of the fibre surface is achieved by the reaction of bisulphite with cystine monoxide residues to give the required cysteine-S-sulphonate groups [311]. 

The neomycin molecule contains both free amino and free hydroxy groups. Many workers have exploited the possibility of chemical de-rivatisation at these positions in attempts to reduce the toxicity of the parent antibiotic. Substitution of methane sulphonate groups at the amino nitrogen has been reported by Umezawa et al83,84 and by Boissier et al . Both groups of workers described the derivative to be less toxic... 

The extremely attractive bright blue hue combined with excellent light fastness of Cl Reactive Blue 19 (7.37) remained unchallenged by competing blue reactive dyes for many years. The aqueous solubility of this structure is inherently low, depending only on the 2-sulphonate group after 1,2-elimination of the sulphate ester has taken place. This has led to... 

In the outstandingly successful Cl Reactive Black 5, two such precursor-bearing units are used in the synthesis of this near-symmetrical bifunctional structure (7.36). Following this precedent, competing bifunctional dyes of analogous structure were designed with two phenylene-l,3-diamine-4-sulphonate groupings to accommodate the reactive systems... 

---