Sulfonic acid, preparation

De Vos et al. have recently published details of supported sulfonic acids prepared by cocondensation of thiol-containing silanes with TEOS[l 1]. The oxidation of these materials was achieved by treatment with hydrogen peroxide, followed by washing with dilute sulphuric... 

Sulfonation of pritnuline-like color bases by the baking process yields sulfonic acids whose azo dye derivatives are more fast to light than those from sulfonic acids prepared in the ordinary way. It is assumed that in the baking process, the sulfo group enters ortho to the amino group, and that this increases the light fastness. This same principle was mentioned in connection with the pyrazolone dyes. 

Karami, B., Zare, Z. and Eskandari, K. 2013c. Molybdate sulfonic acid Preparation, characterization, and apphcation as an effective and reusable catalyst for octahydroxanthene-1,8-dione synthesis. Chem. Pap. 67(2) 145-154. 

Investigations of chemically prepared oligomers with said type of substitution resulted in ESR spectra with hyperfine structure indicative of polaronic triplet di(cation) radicals. These results bear importance with respect to the development of organic ferromagnetic substances. Ferromagnetic behavior also was found by Mi-zobuchi et al. [437] with various experimental techniques applied to a copolymer of aniline and 5-amino-2-naphthalene sulfonic acid prepared by electropolymerization... 

The BNSH-PSA membrane with highly acidic perfluoroalkyl sulfonic acids prepared by solution casting showed a high oxidative and dimensional stability. It also produced a high proton conductivity comparable to the Nafion 117 membrane in the range of 30%-95% RH, regardless of the moderate lEC value (1.91 meq./g) (Figure 4.45). Furthermore, AFM observation supported the formation of the phase-separated structure in which the hydrophilic domains were well dispersed and connected to each other. 

A solution of trifluoroacetic acid in toluene was found to be advantageous for cydization of pyruvate hydrazoncs having nitro substituents[4]. p-Toluene-sulfonic acid or Amberlyst-15 in toluene has also been found to give excellent results in preparation of indole-2-carboxylale esters from pyruvate hydra-zoiies[5,6J. Acidic zeolite catalysts have been used with xylene as a solvent to convert phenylhydraziiies and ketones to indoles both in one-flask procedures and in a flow-through reactor[7]. 

Attempts to prepare the diprOpylamino-5-sulfonic acid by sulfonation in oleum failed (385). With 2-piperidino-4-methylthiazole Ochiai reports cleavage of the 2-piperidino ring (391). 

Direct sulfonation of thiazole, as well as of 2-substituted thiazoles, leads mostly to substitution m the 5-position (330-332). 4-Thiazole sulfonic acid has been prepared through direct sulfonation of 2.5-dibromothiazole with subsequent Rane% Ni reduction (330). Sulfonation of 2.5-dimethyl- and 2-piperidyl-5-methylthiazoles affords the corresponding 4-sulfonic acids as barium salts (247). The 2-hydroxy group facilitates the sulfonation (201. 236). When the 4- and 5-positions are occupied direct sulfonation can occur in the 2-position. 5-hydroxyethyl-4-methyl-2-thiazole sulfonic acid has been prepared in this manner (7). 

More commonly. 2-sulfonic acids (139) are prepared by oxidation of the corresponding A-4-thiazoline-2-thione (Scheme 72). Oxidation can be... 

Alkyl sulfonates are derivatives of sulfonic acids m which the proton of the hydroxyl group is replaced by an alkyl group They are prepared by treating an alcohol with the appropriate sulfonyl chloride usually m the presence of pyridine... 

Of these the most important are the sulfonic acids In general however sulfonic acids are not prepared by oxidation of thiols Arenesulfomc acids (ArS03H) for example are prepared by sulfonation of arenes (Section 12 4)... 

Direct, acid catalyzed esterification of acryhc acid is the main route for the manufacture of higher alkyl esters. The most important higher alkyl acrylate is 2-ethyIhexyi acrylate prepared from the available 0x0 alcohol 2-ethyl-1-hexanol (see Alcohols, higher aliphatic). The most common catalysts are sulfuric or toluenesulfonic acid and sulfonic acid functional cation-exchange resins. Solvents are used as entraining agents for the removal of water of reaction. The product is washed with base to remove unreacted acryhc acid and catalyst and then purified by distillation. The esters are obtained in 80—90% yield and in exceUent purity. 

Stilben-4-yl)naphthotriazoles (2) are prepared by diazotization of 4-amino-stilbene-2-sulfonic acid or 4-amino-2-cyano-4 -chlorostilbene, coupling with an ortho-coupling naphthylamine derivative, and finally, oxidation to the triazole. 

The perfluoroalkane sulfonic acids were fkst reported ki 1954. Trifluoromethanesulfonic acid was obtained by the oxidation of bis(ttifluoromethyl thio) mercury with aqueous hydrogen peroxide (1). The preparation of a series of perfluoroalkanesulfonic acids derived from electrochemical fluotination (ECF) of alkane sulfonyl haUdes was also disclosed ki the same year (2). The synthetic operations employed when the perfluoroalkanesulfonic acid is derived from electrochemical fluotination, which is the best method of preparation, are shown ki equations 1—3. 

Currently, the commercially important methods of preparations of perfluorkiated sulfonic acid derivatives are electrochemical fluotination and sulfur trioxide addition to tetrafluoroethylene with subsequent ring opening. 

Keta.Is, Trimethylpentanediol reportedly forms a cycHc ketal by heating it with benzophenone ia the presence of sulfonic acid catalysts at reflux temperatures ia toluene (64). These are said to be useful as aprotic solvents for ink-jet printing and as inflammation inhibitors for cosmetic preparations... 

Sulfonic acid hydrazides, RSO2NHNH2, are prepared by the reaction of hydraziae and sulfonyl haUdes, generally the chloride RSO2CI. Some of these have commercial appHcations as blowiag agents. As is typical of hydrazides generally, these compounds react with nitrous acid to form azides (26), which decompose thermally to the very reactive, electron-deficient nitrenes (27). The chemistry of sulfonic acid hydrazides and their azides has been reviewed (87). 

Ethyleneimine reacts rapidly with sulfurous acid to give taurine [107-35-7] in high yield, a reaction of importance not only for the preparation of this amino sulfonic acid but also for the decontamination of ethyleneimine solutions (130). 

Naphthalenediol. This diol is prepared by the alkah fusion of 2-hydroxynaphthalene-6-sulfonic acid (Schaffer acid) at 290—295°C. Schaffer acid is usually produced by sulfonation of 2-naphthol with the addition of sodium sulfate at 85—105°C. This acid is also used as a coupling component in the production of a2o dyes such as Acid Black 26. 2,6-Naphthalenediol is used as a component in the manufacture of aromatic polyesters which, as is also tme of the corresponding amides, display Hquid crystal characteristics (52). 

Phthalocyanine sulfonic acids, which can be used as direct cotton dyes (1), are obtained by heating the metal phthalocyanines in oleum. One to four sulfo groups can be introduced in the 4-position by varying concentration, temperature, and reaction time (103). Sulfonyl chlorides, which are important intermediates, can be prepared from chlorosulfonic acid and phthalocyanines (104). The positions of the sulfonyl chloride groups are the same as those of the sulfonic acids (103). Other derivatives, eg, chlormethylphthalocyanines (105—107), / /f-butyl (108—111), amino (112), ethers (109,110,113—116), thioethers (117,118), carboxyl acids (119—122), esters (123), cyanides (112,124—127), and nitrocompounds (126), can be synthesized. 

Sulfonation. Aniline reacts with sulfuric acid at high temperatures to form -aminoben2enesulfonic acid (sulfanilic acid [121 -57-3]). The initial product, aniline sulfate, rearranges to the ring-substituted sulfonic acid (40). If the para position is blocked, the (9-aminoben2enesulfonic acid derivative is isolated. Aminosulfonic acids of high purity have been prepared by sulfonating a mixture of the aromatic amine and sulfolane with sulfuric acid at 180-190°C (41). 

Dyes, Dye Intermediates, and Naphthalene. Several thousand different synthetic dyes are known, having a total worldwide consumption of 298 million kg/yr (see Dyes AND dye intermediates). Many dyes contain some form of sulfonate as —SO H, —SO Na, or —SO2NH2. Acid dyes, solvent dyes, basic dyes, disperse dyes, fiber-reactive dyes, and vat dyes can have one or more sulfonic acid groups incorporated into their molecular stmcture. The raw materials used for the manufacture of dyes are mainly aromatic hydrocarbons (67—74) and include ben2ene, toluene, naphthalene, anthracene, pyrene, phenol (qv), pyridine, and carba2ole. Anthraquinone sulfonic acid is an important dye intermediate and is prepared by sulfonation of anthraquinone using sulfur trioxide and sulfuric acid. 

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