Acid sulfonic

The mam derivatives of the sulfonic acids are obtained by converting them to the corresponding sulfonyl chlorides Hence sulfonic acids and sulfonyl chlorides are often identified through the same derivatives 

From the sulfonic acid or its sodium or potassium salt with phosphorus pentachloride without solvent For directions and examples see Cheronis, p 638, Linstead, p 89, Shrmer, pp 268, 270, Vogel, p 553, Wild, p 161 

From the sulfonyl chloride (prepared from the acid), aniline, and sodium hydroxide For directions and examples see Linstead, p 89, Wild, p 161 From the sulfonyl chloride and aniline See Vogel, p 553 

From the sulfonyl chloride,/i-toluidine and aqueous sodium hydroxide For directions and examples see Vogel, p 553 

Recall from Section 9.13 that CH3C6H4SO2- is called a tosyl group, abbreviated by the letters Ts. For this reason, p-toluenesulfonic acid (also called tosic acid) is abbreviated as TsOH. 

Although much less common than carboxylic acids, sulfonic acids constitute a useful group of organic acids. Sulfonic acids have the general structure RSO3H. The most widely used sulfonic acid, p-toluenesulfonic acid, was first discussed in Section 2.6. 

Sulfonic acids are very stroi acids (pATa values = -7) because their conjugate bases are resonance stabilized, and all the resonance structures delocalize a negative charge on oxygen. The conjugate base of a sulfonic acid is called a sulfonate anion. 

Because sulfonate anions are such weak bases, they make good leaving groups in nucleophilic substitution reactions, as we learned in Section 9.13. 

Two other commonly used sulfonic acids are methanesulfonic acid (CH3SO3H) and tiifluoromethanesulfonic acid (CF3SO3H). Which has the weaker conjugate base Which conjugate base is the better leaving group Which of these acids has the higher pKg  

Reaction of PhSOjH with phosgene, in the presence of dmf and sulfuric acid, gave PhSOjCl in a yield of 98.5% [204]. Similarly, treatment of the bisbenzenesulfonic acid 

Though not strictly related, the last section of this chapter is devoted to sulfenic acid derivatives, which were not extensively studied by mass spectrometry, despite the fact that they are key intermediates in organosulfur chemistry, representing a link between compounds with bivalent sulfur and those containing sulfur in higher oxidation states. 

The electron impact (El) mass spectra of sulfonic acids may be studied, provided special care is taken to control their thermal decomposition in the inlet system of the mass spectrometer. In his early study of the mass spectral fragmentation pattern of p-toluenesulfonic acid, Wiley2 noticed a dependence of the relative intensity of the molecular ion on the temperature and time involved in sample volatilization. o-Toluenesulfonic acid failed to give a reproducible mass spectrum3. More recently, Borthakur and Rao4 found the S-benzylisothiouronium salts of alkylbenzenesulfonic acids to be useful precursors, from which the free acids could be obtained in pure form by decomposition 

Metastable transitions and high resolution mass data supported the major fragmentation routes in the 70 eV mass spectrum of 2,2 -bipyridyl-5-sulfonic acid (8)8. High-mass ions derived from the molecular ion (m/z 236, 100%) by loss of S03 (m/z 156, 28%), HCN (m/z 209, 2%), 03 (m/z 188, 12%) and S02 (m/z 172, 8%) were observed. 

Two FD studies of sulfonic acids in the positive-ion mode have been published. Schiilten and Kiimmler11 examined a variety of sulfonic acids, including alkanesulfonic acids, substituted benzenesulfonic acids, naphthalenesulfonic acids and anthraqui-nonesulfonic acids. Their results can be summarized as follows (a) all the compounds gave high molecular ion intensities, normally with less intense [M + H] + ions, except 

Secondary ion mass spectrometry (SIMS) has also found application in the analysis of organic compounds not prone to thermal evaporation. By this technique sulfanilic acid gave fair abundancies of [M —H] ions15, when bombarded with low primary-ion current densities on a silver target. Sulfonic acids were successfully tested by atmospheric-pressure ion evaporation mass spectrometry and found to produce characteristic negative cluster ions16. 

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The two principal raw material classes used to make detergents are sulfonic acids and phenols. 

Sulfonic acids can come from the sulfonation of oil cuts from white oil production by sulfuric acid treatment. Sodium salts of alkylaromatic sulfonic acids are compounds whose aliphatic chains contain around 20 carbon atoms. The aromatic ring compounds are mixtures of benzene and naphthalene rings. 

The second source of sulfonic acid uses the following reaction scheme alkylation of benzene by a propylene oligomer then sulfonation of the alkylbenzene. 

To solve some of the environmental problems of mixed-acid nitration, we were able to replaee sulfuric acid with solid superacid catalysts. This allowed us to develop a novel, clean, azeotropic nitration of aromatics with nitric acid over solid perfluorinated sulfonic acid catalysts (Nafion-H). The water formed is continuously azeotroped off by an excess of aromatics, thus preventing dilution of acid. Because the disposal of spent acids of nitration represents a serious environmental problem, the use of solid aeid eatalysts is a significant improvement. 

Ethyl /m s -2-butenyl sulfone (86) together with some ethyl vinyl sulfone are obtained by the reaction of ethylene and. SO2 in wet benzene using PdCl2. SO2 behaves mechanistically similarly to CO in this reaction[66]. Hydrosulfination of alkenes with SO2 and H2 is catalyzed by the Pd(dppp) complex. The sulfinic acid 87 is a primary product, which reacts further to give the. S-alkyl alkanethiosulfonates 88 as the major product, and 89 and the sulfonic acid 90 as minor products[67]. 

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]. 

Sulfonation under mild conditions is reported to yield thiazolyl-2-sulfamic acid, which, when heated in H2SO4. rearranges to 2-aminothiazole-5-sulfonic acid (16. 374. 390. 391). Postovskfi. however, reports exactly the opposite rearrangement (367). and spectroscopic evidence supports his conclusion (368) (see Section III.5). 

Acetamidothiazole and its 4-alkyl derivatives react with chloro-sulfonic acid. The structure of the resulting products was a subject of controversy (172. 393-397). N-acetyl-A -(2-thiazolyl)-sulfamoyl chlorides (189) first proposed were then shown to be 2-acetamido-5-chloro-sulfonylthiazoles (190) (Scheme 120) (367. 368. 398). the latter assignment is based on infrared (368) and chemical evidence (367). 

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). 

Oxidation, already described in neutral and acidic media, may also be performed in basic medium. An alkaline solution of H2O2 reacts with 4-thiazoline 2-thione to yield thiazole-2-sulfonic acid (201-203), whereas alkaline oxidation performed with (NH )2S20g yields the disulfides (148). 

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... 

Thiazole sulfonic acid reacts with nucleophiles leading to the corresponding 2-substituted compounds (140. 141, and 142) (Scheme 73) (39, 334). 

Action of HSO3CI on 2-substituted thiazoles affords the 5-chlorosulfonyl derivatives (337, 338). Addition of 6-phenylthiazolo[2,3-e]tetra2ole to oleum opens the tetrazole ring to form 2-azido-4-phenyI-thiazolyl-5-sulfonic acid, isolated as its salt (339). 5-Chloro-sulphonyl derivative is obtained similarly by action of HSO,Cl. 

Similarly, 5-thiazole alkanoic acids and their salts are obtained from thioamides and /3-halo -y-keto acids (695). Thus thioarylamides condensed with 3-aroyl-3-bromopropionic acid (88) in isopropanolic solution in the presence of Na COs give first 4-hydroxy-2-aryl-A-2-thiazoline-5-acetic acid intermediates (89), which were dehydrated in toluene with catalytic amounts of p-toluene sulfonic acid to 2,4-diaryl-5-thiazole acetic acid (90) (Scheme 39) (657), with R = H or Me Ar = Ph, o-, m- or p-tolyl, o-, m-, or P-CIC6H4, 0-, m-, or p-MeOC(iH4, P-CF3C6H4, a-thienyl, a-naphthyl (657). 

Sulfonic acids such as methanesulfomc acid and p toluenesulfomc acid are strong acids comparable m acidity with sulfuric acid... 

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... 

Sulfonation Treatment of benzene with hot concentrated sulfuric acid gives benzenesulfonic acid A sulfonic acid group (—SO2OH) replaces one of the ring hydrogens... 

IS reversible but can be driven to completion by several techniques Removing the water formed m the reaction for example allows benzene sulfonic acid to be obtained m vir tually quantitative yield When a solution of sulfur trioxide m sulfuric acid is used as the sulfonatmg agent the rate of sulfonation is much faster and the equilibrium is dis placed entirely to the side of products according to the equation... 

Very strongly deactivating 0 II —CCI —C=N —SO3H -CF3 —NO2 (acyl chloride) (cyano) (sulfonic acid) (trifluoromethyl) (nitro) Meta directing... 

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