Desulfonation

Processes for Triacetate. There are both batch and continuous process for triacetate. Many of the considerations and support faciUties for producing acetate apply to triacetate however, no acetyl hydrolysis is required. In the batch triacetate sulfuric acid process, however, a sulfate hydrolysis step (or desulfonation) is necessary. This is carried out by slow addition of a dilute aqueous acetic acid solution containing sodium or magnesium acetate (44,45) or triethanolamine (46) to neutrali2e the Hberated sulfuric acid. The cellulose triacetate product has a combined acetic acid content of 61.5%. 

In the batch methylene chloride process, the sulfuric acid concentration can be as low as 1% and only limited desulfonation is required to reach a combined acetic acid content of 62.0%. With perchloric acid catalyst, the nearly theoretical value of 62.5% combined acetic acid is obtained. 

The synthesis of 2,4-dihydroxyacetophenone [89-84-9] (21) by acylation reactions of resorcinol has been extensively studied. The reaction is performed using acetic anhydride (104), acetyl chloride (105), or acetic acid (106). The esterification of resorcinol by acetic anhydride followed by the isomerization of the diacetate intermediate has also been described in the presence of zinc chloride (107). Alkylation of resorcinol can be carried out using ethers (108), olefins (109), or alcohols (110). The catalysts which are generally used include sulfuric acid, phosphoric and polyphosphoric acids, acidic resins, or aluminum and iron derivatives. 2-Chlororesorcinol [6201-65-1] (22) is obtained by a sulfonation—chloration—desulfonation technique (111). 1,2,4-Trihydroxybenzene [533-73-3] (23) is obtained by hydroxylation of resorcinol using hydrogen peroxide (112) or peracids (113). 

Naphthalenesulfonic Acid. The standard manufacture of 2-naphthalenesulfonic acid involves the batch reaction of naphthalene with 96 wt % sulfuric acid at ca 160°C for ca 2 h (13). The product contains the 1- and 2-isomers in a ratio of ca 15 85. Because of its faster rate of desulfonation,... 

Naphthalenedisulfonic acid (Ebert-Merz a-acid) is partially isomerized in sulfuric acid at 160°C to 2,6-naphthalenedisulfonic acid. The reaction takes place by a desulfonation—resulfonation mechanism. 

Many aminonaphthalenesulfonic acids are important in the manufacture of azo dyes (qv) or are used to make intermediates for azo acid dyes, direct, and fiber-reactive dyes (see Dyes, reactive). Usually, the aminonaphthalenesulfonic acids are made by either the sulfonation of naphthalenamines, the nitration—reduction of naphthalenesulfonic acids, the Bucherer-type amination of naphtholsulfonic acids, or the desulfonation of an aminonaphthalenedi-or ttisulfonic acid. Most of these processes produce by-products or mixtures which often are separated in subsequent purification steps. A summary of commercially important aminonaphthalenesulfonic acids is given in Table 4. 

Another example of manufacture in this series is the sulfonation of an aminonaphthalenesulfonic acid, followed by selected desulfonation, to make 6-amino-l,3-naphthalenedisulfonic acid (21). Thus, 2-amino-l-naphthalenesulfonic acid made by amination of 2-hydroxy-1-naphthalenesulfonic acid is added to 20 wt % oleum at ca 35°C. At this temperature, 65 wt % oleum is added and the charge is stirred for 2 h, is then slowly heated to 100°C and is maintained for 12 h to produce 6-amino-l,3,5-naphthalenetrisulfonic acid. The mass is diluted with water and maintained for 3 h at 105°C to remove the sulfo group adjacent to the amino group. After cooling to ca 20°C and filtration, 6-amino-l,3-naphthalenedisulfonic acid is obtained in 80% yield (55). 

Naphthalenediol. This compound darkens rapidly in air. It can be made by fusion of the sultone of 8-hydroxy-1-naphthaIenesulfonic acid with 50 wt % sodium hydroxide at 200—230°C, or by the hydrolytic desulfonation of l,8-dihydroxy-4-naphthalenesulfonic acid. The diol also reacts with ammonia to give 1,8-naphthalenediamine. 

Naphthalenediol. This diol is made by the hydrolytic desulfonation of 2,3-naphthalenediol-6-sulfonic acid at ca 180°C. It is used as a coupler forming a2o dyes which are appHed in reprographic processes. 

Hydroxynaphthalenesulfonic acids are important as intermediates either for coupling components for a2o dyes or a2o components, as well as for synthetic tanning agents. Hydroxynaphthalenesulfonic acids can be manufactured either by sulfonation of naphthols or hydroxynaphthalenesulfonic acids, by acid hydrolysis of arninonaphthalenesulfonic acids, by fusion of sodium naphthalenepolysulfonates with sodium hydroxide, or by desulfonation or rearrangement of hydroxynaphthalenesulfonic acids (Table 6). 

H. Cerfontain, Mechanisticdspects in Aromatic Sulfonation and Desulfonation, Wiley-Interscience, New York, 1968. 

Thermal stabihty of the foaming agent in the presence of high temperature steam is essential. Alkylaromatic sulfonates possess superior chemical stabihty at elevated temperatures (205,206). However, alpha-olefin sulfonates have sufficient chemical stabihty to justify their use at steam temperatures characteristic of most U.S. steamflood operations. Decomposition is a desulfonation process which is first order in both surfactant and acid concentrations (206). Because acid is generated in the decomposition, the process is autocatalytic. However, reservoir rock has a substantial buffering effect. 

Pigment Red 177 [4051-63-2] 65300 anthraquinone bimolecular debromination of l-amino-4-bromoanthraquiQone-2-sulfonic acid, foUowed by desulfonation... 

Sulfonic acids are prone to reduction with iodine [7553-56-2] in the presence of triphenylphosphine [603-35-0] to produce the corresponding iodides. This type of reduction is also facile with alkyl sulfonates (16). Aromatic sulfonic acids may also be reduced electrochemicaHy to give the parent arene. However, sulfonic acids, when reduced with iodine and phosphoms [7723-14-0] produce thiols (qv). Amination of sulfonates has also been reported, in which the carbon—sulfur bond is cleaved (17). Ortho-Hthiation of sulfonic acid lithium salts has proven to be a useful technique for organic syntheses, but has Httie commercial importance. Optically active sulfonates have been used in asymmetric syntheses to selectively O-alkylate alcohols and phenols, typically on a laboratory scale. Aromatic sulfonates are cleaved, ie, desulfonated, by uv radiation to give the parent aromatic compound and a coupling product of the aromatic compound, as shown, where Ar represents an aryl group (18). 

Sulfonic acids may be hydrolytically cleaved, using high temperatures and pressures, to drive the reaction to completion. As would be expected, each sulfonic acid has its own unique hydrolytic desulfonation temperature. Lower alkane sulfonic acids possess excellent hydrolytic stability, as compared to aromatic sulfonic acids which ate readily hydrolyzed. Flydrolytic desulfonation finds use in the separation of isomers of xylene sulfonic acids and other substituted mono-, di-, and polysulfonic acids. 

Sulfonation—Desulfonation of Chlorobenzenes. Sulfonation of chlorobenzenes can also be used to produce chlorophenols. Sulfonation is carried out at 60—80°C using oleum at 15—20%. The subsequent desulfonation usually calls on aqueous alkaU solutions at 15—20% at temperatures between 170 and 230°C. 

As in the nitration of naphthalene, sulfonation gives the 1-substituted naphthalene. However, because the reverse reaction (desulfonation) is appreciably fast at higher temperatures, the thermodynamically controlled product, naphthalene-2-sulfonic acid, can also be obtained. Thus it is possible to obtain either of the two possible isomers of naphthalene sulfonic acid. Under kineticaHy controlled conditions naphthalene-l-sulfonic acid [85-47-2] (82) is obtained thermodynamic control gives naphthalene-2-sulfonic acid [120-18-3] (83). 

Desulfonation reaction (reductive and oxidative desulfonation, nucleophilic substitution, elimination, and SO2 extrusion) in synthesis and transformations of heterocycles 99T10547. 

The nitro groups in Eqs 7 88-7 90 are readily replaced by hydrogen with dn hydndeunder radical condidons as discussed already However, the nitro groups in the ct-nitrosulfides or fi-nitrosulfides are not replaced by hydrogen on treatment with dn hydnde but the reacdon affords desulfonated products fEq 7 51 and alkenes fEq 7 97 such radical eliminadon e disaissed in Secdon 7 3 1 fsee Eqs 7 91 and 7 93 ... 

The sulfonation of an aromatic ring with SO3 and H2S04 is reversible. That is, heating benzenesulfonic acid with H2SO4 yields benzene. Show the mechanism of the desulfonation read ion. What is the electrophile ... 

Ar,Af -Disulfonyldibenzodiazocinediones (see Section l.S.1.1.1.)2 can be desulfonated by treatment with sulfuric acid depending on the conditions, different products are obtained.2, 7... 

Allylic sulfones and a, /5-unsaturated sulfones are known to be in equilibrium314-319. Allylic sulfones, such as 242, isomerize to a, /5-unsaturated sulfones 243 upon treatment with a catalytic amount of potassium t-butoxide in dry THF. The a, /5-unsaturated sulfones can be converted to the corresponding olefins upon desulfonation with sodium amalgam320 or aluminium amalgam294,321. Since treatment of allylic sulfones with potassium-graphite gives 2-alkenes, alkylation of allylic sulfones and subsequent desulfonation is a useful process for the synthesis of olefins, as shown in Scheme 6. 

A review article is an intensive survey of a rather narrow field for example, the titles of some recent reviews are Desulfonation Reactions Recent Developments , Pyrrolizidine and Indolizidine Syntheses Involving 1,3-Dipolar Cycloaddtion , and From Corrin Chemistry to Asymmetry Catalysis—A Personal Account. A good review article is of enormous value, because it is a thorough survey of all the work done in the field under discussion. Review articles are printed in review journals and in certain books. The most important review journals in organic chemistry (though most are not exclusively devoted to organic chemistry) are shown in Table A.3. Some of the journals listed in Table A.l, for example, the Bull Soc. Chim. Fr. and J. Organomet. Chem. also publish occasional review articles. 

Locher HH, T Leisinger, AM Cook (1991a) 4-Sulfobenzoate 3,4-dioxygenase. Purification and properties of a desulfonative two-component system from Comamonas testosteroni T-2. Biochem J 274 833-842. 

Ztirrer D, AM Cook, T Leisinger (1987) Microbial desulfonation of substituted naphthalenesulfonic acids and benzenesulfonic acids. Appl Environ Microbiol 53 1459-1463. 

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