Of sulfonic anhydrides

An excess of thionyl chloride - dimethylformamide catalyst is used to prevent formation of sulfonic anhydrides. A stoichiometric amount of thionyl chloride gives a much reduced yield. 

Alkyl and aryl disulfides, when treated with N2O5, give high yields of sulfonic anhydrides 9. Diethyl azodicarboxylate forms a 1 1 adduct with mercaptans which, when treated with a second mercaptan, gives a good yield of the unsymmetrical disulfide O,... 

Scheme 33 (a) Monomer combination NTDA and BDSA used for the synthesis of sulfonated anhydride-terminated polyimide. (b) Monomer combination 6FDA and TAPA used for the synthesis of amine-terminated hb-PI [288]... 

Free oil in LAS consists not only of unsulfonated alkylbenzene but also of sulfones. Anhydrides are also formed in the sulfonation reaction but are completely eliminated from the commercial product by a hydrolysis step during LAS production (54) ... 

TBPA is prepared in high yield by the bromination of phthalic anhydride in 60% oleum (51). The use of oleum as the bromination solvent results in some sulfonation of the aromatic ring (52). Sulfonated material is removed by hydrolyzing the anhydride with dilute NaOH, filtering and acidifying with dilute HCl. The precipitated acid is washed several times with hot water and reconverted to the anhydride by heating at 150°C for several hours. 

A.lkyl Sulfosuccinate Half Asters. These detergents are prepared by reaction of maleic anhydride and a primary fatty alcohol, followed by sulfonation with sodium bisulfite. A typical member of this group is disodium lauryl sulfosucciaate [26838-05-1]. Although not known as effective foamers, these surfactants can boost foams and act as stabilizers when used ia combination with other anionic surfactants. In combination with alkyl sulfates, they are said to reduce the irritation effects of the latter (6). 

Sulfonic acids may be subjected to a variety of transformation conditions, as shown in Figure 2. Sulfonic acids can be used to produce sulfonic anhydrides by treatment with a dehydrating agent, such as thionyl chloride [7719-09-7J. This transformation is also accomphshed using phosphoms pentoxide [1314-56-3J. Sulfonic anhydrides, particulady aromatic sulfonic anhydrides, are often produced in situ during sulfonation with sulfur trioxide. Under dehydrating conditions, sulfonic acids react with substituted aromatic compounds to give sulfone derivatives. 

These authors suggest that the reaction may proceed through the formation of their mixed anhydrides , and illustrate a metal ion templated, mixed carboxylic-sulfonic anhydride. 

Tnfluoroacetic anhydnde in a mixture with sulfuric acid is an efficient reagent for the sulfonylation of aromatic compounds [44] The reaction of benzene with this system in nitromethane at room temperature gives diphenyl sulfone in 61% yield Alkyl and alkoxy benzenes under similar conditions form the corresponding diaryl sulfones in almost quantitative yield, whereas yields of sulfones from deactivated arenes such as chlorobenzene are substantially lower [44] The same reagent (tnfluoroacetic anhydride-sulfunc acid) reacts with adamantane and its derivatives with formation of isomeric adamantanols, adamantanones, and cyclic sultones [45]... 

A heterocyclic ring may be used in place of one of the benzene rings without loss of biologic activity. The first step in the synthesis of such an agent starts by Friedel-Crafts-like acylation rather than displacement. Thus, reaction of sulfenyl chloride, 222, with 2-aminothiazole (223) in the presence of acetic anhydride affords the sulfide, 224. The amine is then protected as the amide (225). Oxidation with hydrogen peroxide leads to the corresponding sulfone (226) hydrolysis followed by reduction of the nitro group then affords thiazosulfone (227). ... 

SS/MA may be structured in different ratios of sulfonated styrene to maleic anhydride. Typically, it is 3 1 (20,000 MW) or 1 1 (15,000 MW). The application rates of all calcium phosphate scale/sludge inhibitors or stabilizers vary, based on the amount of calcium present in the cooling system, with increased calcium hardness leading to higher levels of polymer required. 

An important role must be attributed to intermediate mixed anhydrides of sulfonic acids and mineral acids sulfonic acid anhydrides are reported to need Friedel-Crafts conditions to generate sulfones327,476. Instead of arenesulfonic acids, their methyl esters may undergo insertion of sulfur trioxide477,478 yielding mixed anhydrides, which in turn furnish... 

Thiophene 1,1-dioxide (61) is too unstable to isolate and dimerizes with loss of S02 to give 3a, 7a-dihydrobenzothiophene 1,1-dioxide (172) in 34%113. However, alkyl-substituted thiophene 1,1-dioxides can serve as dienes in the Diels-Alder reaction, since the aromatic properties of the thiophene nucleus are lost completely and the n-electrons of the sulfur atom are used for forming the bond with oxygen. The sulfones 173-178 are found to react with two moles of maleic anhydride at elevated temperature to give bicyclic anhydrides114. Thus, at high reaction temperature, S02 is split off to give cyclohexadiene... 

Sulfur compounds have also been widely studied as activating agents for polyesterification reactions. p-Toluenesulfonyl chloride (tosyl chloride) reacts with DMF in pyridine to form a Vilsmeir adduct which easily reacts with carboxylic acids at 100-120° C, giving highly reactive mixed carboxylic-sulfonic anhydrides.312 The reaction is efficient both for aromatic dicarboxylic acid-bisphenol312 and hydroxybenzoic acid314 polyesterifications (Scheme 2.31). The formation of phenyl tosylates as significant side products of this reaction has been reported.315... 

The formation of sulfone is assisted in particular by high reaction temperatures, whereas the formation of anhydride is influenced by the S03/LAB ratio and the residence time [152]. Usually an S03/LAB ratio between 1-1.1 to 1 is chosen and the residence time kept as short as possible [153-155]. 

The ability of sulfonic acids to form anhydrides was already described on page 81. In contrast to aqueous acids and alkalis, LAS is stable. This behavior is used in the differentiation between alkyl sulfates and alkylether sulfates, which are easily hydrolyzed from aqueous acids. 

Sodium hydroxyalkanesulfonates may be determined in the presence of an unsaturated hydrocarbon, including sodium alkenesulfonate. The sulfonates are converted to the free sulfonic acids using a slight excess of 2,4-dinitrobenzene-sulfonic acid. The hydroxyl group of the sulfonic acid liberated is acetylated in ethyl acetate solution by a known excess of acetic anhydride. The unconsumed anhydride is hydrolyzed by a pyridine-water mixture and the acids titrated potentiometrically with standard sodium hydroxide solution. The hydroxy-alkanesulfonate content is calculated after correction for any traces of acidity or alkalinity in the original sample. 

In the first step an S03 molecule is inserted into the ester binding and a mixed anhydride of the sulfuric acid (I) is formed. The anhydride is in a very fast equilibrium with its cyclic enol form (II), whose double bonding is attacked by a second molecule of sulfur trioxide in a fast electrophilic addition (III and IV). In the second slower step, the a-sulfonated anhydride is rearranged into the ester sulfonate and releases one molecule of S03, which in turn sulfonates a new molecule of the fatty acid ester. The real sulfonation agent of the acid ester is not the sulfur trioxide but the initially formed sulfonated anhydride. In their detailed analysis of the different steps and intermediates of the sulfonation reaction, Schmid et al. showed that the mechanism presented by Smith and Stirton [31] is the correct one. 

Neutralization leads to the salt of the a-sulfo fatty acid ester, but only if the neutralization step is delayed. If the neutralization is immediate the a-sulfonated anhydride forms a disalt of the a-sulfo fatty acid as a byproduct [38]. The production of the disalt is also effected by the ratio between S03 and the ester. A high surplus of S03 would shorten the reaction time, but the amount of disalt in the end product would increase. For 90°C and 30 min an optimal S03/es-ter ratio is 1.2 1 [37]. 

A mixture of sulfonated styrene-maleic anhydride copolymer and polymers prepared from acrylic acid or acrylamide and their derivatives [759] are dispersants for drilling fluids. The rheologic characteristics of aqueous well drilling fluids are enhanced by incorporating into the fluids small amounts of sulfonated styrene-itaconic acid copolymers [761] and an acrylic acid or acrylamide polymer [755]. 

In copolymers containing the styrene sulfonate moiety and maleic anhydride units, the maleic anhydride units can be functionalized with alkyl amine [1411-1416]. The water-soluble polymers impart enhanced deflocculation characteristics to the mud. Typically, the deflocculants are relatively low-molecular-weight polymers composed of styrene sodium sulfonate monomer maleic anhydride, as the anhydride and/or the diacid and a zwitterionic functionalized maleic anhydride. Typically the molar ratio of styrene sulfonate units to total maleic anhydride units ranges from 3 1 to 1 1. The level of alkyl amine functionalization of the maleic anhydride units is 75 to 100 mole-percent. The molar concentrations of sulfonate and zwitterionic units are not necessarily equivalent, because the deflocculation properties of these water-soluble polymers can be controlled via changes in their ratio. 

Trifluoromethanesulfonates of alkyl and allylic alcohols can be prepared by reaction with trifluoromethanesulfonic anhydride in halogenated solvents in the presence of pyridine.3 Since the preparation of sulfonate esters does not disturb the C—O bond, problems of rearrangement or racemization do not arise in the ester formation step. However, sensitive sulfonate esters, such as allylic systems, may be subject to reversible ionization reactions, so appropriate precautions must be taken to ensure structural and stereochemical integrity. Tertiary alkyl sulfonates are neither as easily prepared nor as stable as those from primary and secondary alcohols. Under the standard preparative conditions, tertiary alcohols are likely to be converted to the corresponding alkene. 

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