Aromatic substitution reactions sulfonation

The hydroxyl group is a strongly activating, ortho- and para-directing substituent in electrophilic aromatic substitution reactions (Section 16.4). As a result, phenols are highly reactive substrates for electrophilic halogenation, nitration, sulfonation, and lTiedel-Crafts reactions. 

Smith, Jason A., 431 Sn2+ compounds, 233 Sn4+ compounds, 232 SNAr reaction. See also Nucleophilic aromatic substitution reaction poly(arylene ether sulfone) synthesis via, 336-340... 

The polymers used in this study were prepared by a nucleophilic activated aromatic substitution reaction of a bisphenate and dihalo diphenyl sulfone ( ). The reaction was carried out in an aprotic dipolar solvent (NMP) at 170°C in the presence of potassium carbonate (Scheme 1) (5,6). The polymers were purified by repeated precipitation into methanol/water, followed by drying to constant weight. The bisphenols used were bisphenol-A (Bis-A), hydroquinone (Hq) and biphenol (Bp). Thus, the aliphatic character of Bis-A could be removed while retaining a similar aromatic content and structure. The use of biphenol allows an investigation of the possible effect of extended conjugation on the radiation degradation. 

Given the reactants, write the structures of the main organic products of the common electrophilic aromatic substitution reactions (halogenation, nitration, sulfonation, alkylation, and acylation). 

The sulfoxidation of benzene (Table 4, entry 38) yields benzenesulfonic acids and the respective derivatives. The electrophilic aromatic substitution reaction gives high yields and aqueous sulfuric acid or oleum is used for the sulfonation reaction, which is performed in cascades of reactor vessels. 

Two of the reactions that are used in the industrial preparation of detergents are electrophilic aromatic substitution reactions. First, a large hydrocarbon group is attached to a benzene ring by a Friedel-Crafts alkylation reaction employing tetrapropene as the source of the carbocation electrophile. The resulting alkylbenzene is then sulfonated by reaction with sulfuric acid. Deprotonation of the sulfonic acid with sodium hydroxide produces the detergent. 

The cyclopentadienyl anion 13 is an efficiently resonance-stabilized anion in which all the carbon-carbon bond lengths are equal (Figure 1.9). It forms stable compounds, of which ferrocene (14) is an example, which undergo aromatic substitution reactions such as sulfonation and acetylation. 

Sulfonation (Section 18.4) An electrophilic aromatic substitution reaction in which benzene reacts with SOsH to give a benzene-sulfonic acid, C6H5SO3H. 

Sulfonation is unusual among electrophilic aromatic substitution reactions in its reversibility. It is also unusual in another way in sulfonation, ordinary hydrogen (protium) is displaced from an aromatic ring about twice as fast as deuterium. These two facts are related to each other and, as we shall see in Sec. 11.16, give us a more detailed picture of sulfonation and of electrophilic aromatic substitution in general. 

The pyridine ring undergoes electrophilic aromatic substitution reactions with great difficulty. Halogenation and sulfonation can be carried out under drastic conditions, but nitration occurs in veiy low yield, and Friedel-Crafts reactions are not successful. Reactions usually give the 3-substituted product. 

It forms stable compounds, of which ferrocene (14) is an example, which undergo aromatic substitution reactions such as sulfonation and acetylation. 

Benzene s aromaticity causes it to undergo electrophilic aromatic substitution reactions. The electrophilic addition reactions characteristic of alkenes and dienes would lead to much less stable nonaromatic addition products. The most common electrophilic aromatic substitution reactions are halogenation, nitration, sulfonation, and Friedel-Crafts acylation and alkylation. Once the electrophile is generated, all electrophilic aromatic substitution reactions take place by the same two-step mechanism (1) The aromatic compound reacts with an electrophile, forming a carbocation intermediate and (2) a base pulls off a proton from the carbon that... 

Benzene rings with substituents other than halo, nitro, sulfonic acid, alkyl, and acyl can be prepared by first synthesizing one of these substituted benzenes and then chemically changing the substituent. The kinds of substituents that can be placed on benzene rings are greatly expanded by reactions of arene dia-zonium salts, nucleophilic aromatic substitution reactions, and reactions involving a benzyne intermediate. The relative positions of two substituents on a benzene ring are indicated either by numbers or by the prefixes ortho, meta, and para. 

Aromatic sulfonation, like nitration, balogenation, alkylation, and acylation, is a typical electrophilic substitution reaction. Sulfonation, however, differs from these other reactions in two marked respects it is reversible, and reaction temperature can, in certain cases, have an important influence on the position of the entering group, as shown on p. 344. These characteristics have tended to complicate studies of the reaction mechanism and rate of sulfonation and to render difficult the drawing of general conclusions. Other factors having the same effect are the tendency of sulfur trioxide to form a complex with the sulfonic acids and the pronounced tendency of all Lubs, pp. 534ff. 

Aromatic substitution reactions, including sulfonation, are conceived as proceeding in two steps, the first involving reagent attack and the second proton removal. The process may be schematized as follows, for the sulfonation of benzene with sulfuric acid with monomeric SO3 as the active reagent ... 

Consider an aromatic substitution reaction to make the sulfonated compound. Rank the following from 1 (most reactive) to 4 (least reactive). 

Other typical electrophilic aromatic substitution reactions—nitration (second entry), sulfonation (fourth entry), and Friedel-Crafts alkylation and acylation (fifth and sixth entries)—take place readily and are synthetically useful. Phenols also undergo electrophilic substitution reactions that are limited to only the most active aromatic compounds these include nitrosation (third entry) and coupling with diazonium salts (seventh entry). 

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