Sulphonation with sulphur trioxide

Synthetic sulphonates, in contrast, are derived from the sulphonation of feedstocks not derived directly from petroleum. The feedstocks commonly used to prepare this class of sulphonates have been polydodecyl benzene bottoms (byproducts of household detergent manufacture) or alkylated benzenes produced specifically as feedstocks for lubricant additive sulphonates. The following generalized reaction sequence. Reaction sequence (7.6), describes the formation of a synthetic alkylate and sulphonation with sulphur trioxide [19], to yield the synthetic sulphonic acid ... 

Another class of sulphonates is the a-olefin sulphonates which are prepared by reacting linear a-olefin with sulphur trioxide, typically yielding a mixture of alkene sulphonates (60-70%), 3- and 4-hydroxyalkane sulphonates ( 30%), and some disulphonates and other species. The two main a-olefin fractions used as starting material are C 2 ie Fatty acid and ester sulphonates are produced... 

Sulphur trioxide and its adducts usually react with terminal alkenes to produce quantitative yields of the terminal alkenic sulphonic acid (equation 16)140"145. However in a few instances it has been reported that a mixture of products is obtained146"150, as shown in equation 17, or else addition across the double bond takes place141,144, as shown in equation 18. Polyfluorovinyl ethers react with sulphur trioxide to give, upon hydrolysis, / -ketosulphonic acids in excellent yield151. 

Reaction of styrene and 1,1-diphenylethene with sulphur trioxide-dioxane complex has been used for the synthesis of six-membered sultones330,331, as shown in equation 72. A similar product has also been suggested from the reaction of 2-methylpropene with the same sulphonating reagent332. 

While the saturated hydrocarbons are but slowly affected by sulphuric acid or sulphur trioxide, their derivatives react more energetically with these reagents. When alcohol, for example, is treated with sulphur trioxide, sulphonation takes place, that is, the alcohol is converted into a sulphonic acid —... 

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... 

With dinitrogen pentoxide pyridine gives 1-nitropyridinium nitrate sa and with nitronium fluoborate the corresponding fluoborate is formed Pyridine forms a 1 1 complex with phosphorus pentachloride Sc with sulphur dioxidei29 (43) and with sulphur trioxide o (44). The last is useful as a sulphonating agent (p. 80), and is formed from its components in carbon tetrachloride, from pyridine and fuming sulphuric acid, and from pyridine and chlorosulphonic acid. Its reactions are discussed later (p. 177). 

The sulphonic acids are usually prepared by the action of sulphuric acid upon a compound. The concentration of the acid and the temperature of reaction are varied according to the reactivity of the compound. Often oleum is used or even chiorosulphonic acid. Alternatively sulphur trioxide complexed to pyridine or dioxan can be used with reactive substrates. Aminosulphonic acids such as sulphanilic and naphthionic acids are most conveniently prepared by heating the sulphate of the amine at ISO C. 

The first kinetic study appears to have been that of Martinsen148, who found that the sulphonation of 4-nitrotoluene in 99.4-100.54 wt. % sulphuric acid was first-order in aromatic and apparently zeroth-order in sulphur trioxide, the rate being very susceptible to the water concentration. By contrast, Ioffe149 considered the reaction to be first-order in both aromatic and sulphur trioxide, but the experimental data of both workers was inconclusive. The first-order dependence upon aromatic concentration was confirmed by Pinnow150, who determined the equilibrium concentrations of quinol and quinolsulphonic acid after reacting mixtures of these with 40-70 wt. % sulphuric acid at temperatures between 50 and 100 °C the first-order rate coefficients for sulphonation and desulphonation are given in Tables 34 and 35. The logarithms of the rate coefficients for sulphonation... 

The lamp method involves combustion of a sample of sulphone in a closed system with an atmosphere of 30% oxygen and 70% carbon dioxide214. The mixture of sulphur dioxide and sulphur trioxide formed is converted in situ to sulphate by oxidation with hydrogen... 

The situation that was described in the previous accident happened again and even twice, with o-nitrotoluene and p-nitrotoluene during their sulphonation. Oleum containing 24% sulphur trioxide had been added to o-nitrotoiuene at 32 C. The reaction went out of control and caused the 2 I reactor to break and a very large volume of carbonised compound to be ejected (this was probably due to the decomposition of the sulphonic acid formed) ... 

H acid (4.2) is possibly the most important single naphthalene-based intermediate. The preparation of this intermediate starts with a high-temperature sulphonation of naphthalene using 65% oleum (anhydrous sulphuric acid in which 65% by mass of sulphur trioxide has been dissolved) to give mainly naphthalene-1,3,6-trisulphonic acid, the nitration product from which is purified by selective isolation. Reduction of the nitro group followed by hydrolysis of the 1-sulphonic acid substituent by heating with sodium hydroxide solution at 180 °C completes the process (Scheme 4.27). 

The copolymer produced in this way has been found to be insoluble and infusible but is still chemically reactive. On heating the polymer with a mixture of sulphur trioxide and sulphuric acid, the sulphonic acid group gets introduced into the aromatic rings. The resin so formed is known as a cation exchanger. 

Since N02 and S03H are substituents of the second order, a second substituent enters in the m-position. Oleum containing a high percentage of sulphur trioxide finally converts benzene into benzene tri-sulphonic acid. Chlorosulphonic acid condenses with aromatic hydrocarbons, giving aryl sulphochlorides. 

Sulphonation Pyrrole, furan and thiophene undergo sulphonation with the pyridine-sulphur trioxide complex (CsHsN+SOs ). 

Benzene reacts with fuming sulphuric acid at room temperature to give henzenesulphonic acid. Fuming sulphuric acid contains added sulphur trioxide (SO3). Sulphonation of benzene can also be carried out with concentrated H2SO4, but with slower speed. In both cases, SO3 acts as an electrophile. 

It has already been recorded (p. 142) that hydrogen chloride and sulphur trioxide react to produce chlorosulphonic acid. The alkali chlorides, on the other hand, form chloropyrosulphonates, e.g. C1S02.0. S02.0Na, which are crystalline solids, decomposed by water 2 the alkali fluorides, however, yield the corresponding fluorosulphonates, such as F.S03Na3 (see p. 86). Sodium nitrite produces a nitrosotri-sulphonate, NQ2(S03)3Na.2 Alkali chlorides may be converted to sulphates with evolution of chlorine by the action at 300° to 600° C. of a mixture of sulphur trioxide and air. No fusion occurs nor does the evolved gas contain any sulphur dioxide.4... 

Amidosulphonie Acid, NH2.SOsH, may be obtained by the action of sulphur trioxide on dry ammonia.2 When an aqueous solution of hydroxylamine hydrochloride is saturated with sulphur dioxide and afterwards evaporated, amidosulphonie acid is obtained.3 Potassium imidosulphonate, NH(S03K)2, and potassium nitrilosulphonate, N(SOaK)a, are both decomposed by hot water with formation of potassium amido-sulphonate 4... 

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