Benzenedisulfonic acids

Alkali Fusion of /u-Benzenedisulfonic Acid. Even though this process like the previous one is a very ancient one, it is still the main route for the synthesis of resorcinol. It has been described in detail previously and does not seem to have drastically evolved since 1980. It involves the reaction of benzene with sulfuric acid to form y -benzenedisulfonic acid which is then converted to its disulfonate sodium salt by treatment with sodium sulfite. In a second step, this salt is heated to 350°C in the presence of sodium hydroxide yielding the sodium resorcinate and sodium sulfite. 

After sulfuric acid work-up (accompanied by the formation of sodium sulfate), the resorcinol is extracted and isolated in a 94% yield based on y -benzenedisulfonic acid [98-48-6]. In addition to the technical complexity that goes along with the manipulation of soHds at high temperature, this process produces large amounts of salts (sulfite and sulfate salts) which economically as well as environmentally are not always desired. 

Benzenedisulfonic acid [831-59-4] (disodium salt), produced by the neutralization of the disulfonic acid with sodium sulfite [7757-83-7] is used in the manufacture of resorcinol [108-46-3] (1,3-benzenediol) (2), a chemical component found in mbber products and wood adhesives (72). The disodium salt is fused with sodium hydroxide, dissolved in water, and acidified to produce resorcinol, which is isolated via extraction (73). 

Sulfonation. Benzene is converted iato benzenesulfonic acid [98-11-3] C H SO, upon reaction with fuming sulfuric acid (oleum) or chlorosulfonic acid. y -Benzenedisulfonic acid [98-48-6] CgHgS20, is prepared by reaction of benzene-sulfonic acid with oleum for 8 h at 85°C. Often under these conditions, appreciable quantities ofT -benzenedisulfonic acid [31375-02-7] are produced. 1,3,5-Benzenetrisulfonic acid [617-99-2] C H S Og, is produced by heating the disulfonic acid with oleum at 230°C (21). 

Minor Uses. Small amounts of benzene find use in production of benzene-sulfonic acid. y -Benzenedisulfonic acid is used to produce resorcinol [108-46-3] (1,3-dihydroxybenzene). Benzene is thermally dimerized to yield biphenyl [92-52-4] Benzene can also be converted... 

When benzene undergoes disulfonation, rw-benzenedisulfonic acid is formed. The first sulfonic acid group to go on directs the second one rneta to itself. 

Meanwhile, the R-R coupling (see Sect. 2.2) has evidently found general acceptance as the main reaction path for the electropolymerization of conducting polymers The ionic character of the coupling species explains why polar additives such as anions or solvents with high permittivity accelerate the rate of polymerization and function as catalysts. Thus, electropolymerization of pyrrole is catalyzed in CHjCN by bromide ions or in aqueous solution by 4,5-dihydro-1,3-benzenedisulfonic acid The electrocatalytic influence of water has been known since the work... 

U.S. consumption pattern 1999, 3 619t U.S. producers, 3 610t vapor-phase nitration of, 17 257 vinyl chloride reactions with, 25 632 world production by country, 3 611-612t Benzene-based catalyst technology, 15 500 Benzene-based fixed-bed process technology, 15 505-506 Benzene chlorination process, of phenol manufacture, 18 751 m-Benzenedisulfonic acid, 3 602 p-Benzenedisulfonic acid, 3 602 Benzene feedstock, 23 329 Benzene hexachloride, 3 602 Benzene manufacture, toluene in, 25 180-181... 

More important is the transformation of benzene to 1,3-benzenedisulfonic acid utilized in the manufacture of resorcinol.97 According to an older method benzene is sulfonated in two steps first by 100% sulfuric acid at 100°C, and then by 65% oleum at 80-85°C. The Hoechst new continuous one-step process applies sulfur trioxide at 140-160°C in molten 1,3-benzenedisulfonic acid. m-Diisopropylbenzene, via its dihydroperoxide is, however, displacing this process. 

Benzenedisulfonic acid, AH12 Benzenesulfonamlde, AH32 Benzenesu1fon 1c acid, AH10 Benzenesul fonyl hydraz i de, AH +8... 

The tetroxide (158) was formed on heating the dipotassium salt (157) with chlorosulfonic acid. 1,2-Benzenedisulfonic acid, in turn, has been prepared by diazotization of o-aminoben-zenesulfonic acid, conversion into the mercaptobenzenesulfonic acid, and final oxidation. 

The first example is an accident (August, 1970) which occurred during the process of coproducing m-benzenedisulfonic acid and toluenesulfonic acid by the simultaneous sulfonation of benzene and toluene in the same reactor. One person was killed and 6 wounded 9). ... 

In an iron, porcelain, or enameled vessel provided with stirrer and reflux condenser, 200 grams of benzene is mixed carefully over a period of about 30 minutes with 450 grams of oleum containing 10 per cent SO3. The temperature should not be allowed to rise above 75° until the mixing is complete, then it is raised to 110°. Higher temperatures are not recommended, since the formation of disulfonic acid occurs readily. (Benzenedisulfonic acid is formed more easily than the literature would indicate. See the preparation of benzene-m-disulfonic acid, page 143.) After about 1.5 to 2 hours, the benzene has all disappeared. 

The benzenedisulfonic acids are of little interest, except that benzene-1,3-disulfonic acid is a source of 1,3-dihydroxybenzene (see Chapter 4). The benzene dicarboxylic acids are more important. Benzene-1,2-dicarboxylic acid (phthalic acid, 8) can be converted into phthalic anhydride (9), which is a typical acid anhydride, reacting with amines and alcohols and also taking part in Friedel-Crafts reactions. Phthalimide (10), produced by reaction of the anhydride with ammonia, is weakly acidic and forms a potassium salt with ethanolic potassium hydroxide. 

Treatment of snifanilic nV/(/7-H2NC6H4SO3H) with 3 moles of bromine yields 2,4,6-lribromoaniline. Treatment of 4-hydroxy-l,3-benzenedisulfonic acid with nitric acid yields picric acid, 2,4,6-trinitrophenol. (a) Outline the most probable mechanism for the replacement of — SO3H by Br and by —NO2. (b) To what general class of organic reactions do those reactions belong ... 

Ethylbenzyl chloride Ethylene dibromide V,V -Dinitroethylenediamine Hexaethyl tetraphosphate M ethylbenzyl alcohol m-Benzenedisulfonic acid Methylbenzyl chloride V-Bromosuccinimide Octamethyl pyrophosphoramide p-Aminosalicylic acid Pentaerythritol tetranitrate Tris-(/3-chloroethyl) amine Tetraethylammonium bromide Tetraethyl pyrophosphate 2,2,6,6-Tetramethylolcyclohexanol... 

The indicator substance for iron determination is Tiron [4,5-dihydroxy-l,3-benzenedisulfonic acid, disodium salt] (Acros Organics, Geel, Belgium). The stock solution used to prepare the calibration samples contains Ig Fe/L (solution of Fe(N03)3-4aq in HNO3 0.5N) (Panreac Quimica, Barcelona, SP). 

A buffer mixture of ammonium sulfate and sulfuric acid can also be employed for the elution of aluminum. Its specific detection is carried out via derivatization with Tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt) with subsequent photometry of the complex formed at a wavelength of 313 nm (Fig. 3-160). In an acidic sulfate medium aluminum ions exist as A1S04+ ions depending on the hydrogen ion and sulfate ion concentration. The parameter determining retention is, in this case, the ammonium sulfate concentration. 

A post-column derivatization with subsequent photometric detection has also been developed for the determination of aluminium. Using a mixture of ammonium sulfate and sulfuric acid, aluminium is separated as A1S04+ ion on a cation exchanger. It forms a stable complex with the disodium salt of 4,5-dihydroxy-l,3-benzenedisulfonic acid (Tiron) at pH 6.2 which can be detected at 313 nm. 

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