Sodium benzenesulfonate, reaction with

Sodium benzenesulfonate, reaction with piperidine to form N-phenylpi-peridine, 40, 75... 

A Methylamino)phenol. This derivative (15) is easily soluble ia ethyl acetate, ethanol, diethyl ether, and benzene. It is also soluble ia hot water, but only spatingly soluble ia cold water. Industrial synthesis is by heating 3-(A/-methylamino)benzenesulfonic acid with sodium hydroxide at 200—220°C (179) or by the reaction of resorciaol with methylamiae ia the presence of aqueous phosphoric acid at 200°C (180). 

A A Diethylamino)phenol. This derivative (16) forms rhombic bipyramidal crystals. Industrial synthesis is analogous to the previously described synthesis of 3-(/V,/V-dimethy1amino)pheno1 from resorciaol and diethylamiae, by reaction of 3-(Ai,A/-diethylamiQo)benzenesulfonic acid with sodium hydroxide, or by alkylation of 3-amiaophenol hydrochloride with ethanol. 

The reaction of benzenesulfonic acid with sodium hydroxide (first entry in Table 24.3) proceeds by the addition-elimination mechanism of nucleophilic aromatic substitution (Section 23.6). Hydroxide replaces sulfite ion (S03 ) at the carbon atom that bear s the leaving group. Thus, p-toluenesulfonic acid is converted exclusively to p-cresol by an analogous reaction ... 

Reaction of benzenesulfonic acid with sodium hydroxide This is the oldest method for the preparation of phenol. Benzene is sulfonated and the benzenesulfonic acid heated with molten sodium hydroxide. Acidification of the reaction mixture gives phenol. 

Sulfonation of polybenzimidazole was also accomplished by proton abstraction with an alkali metal hydride followed by reaction with sodium (4-bromomethyl)benzenesulfonate. The degree of sulfonation in this synthesis can be controlled by the... 

Historically, phenol was produced by the distillation of coal tar. Today, phenol is prepared by one of several synthetic methods, such as the fusion of sodium benzenesulfonate with sodium hydroxide followed by acidification the hydrolysis of chlorobenzene by dilute sodium hydroxide at high temperature and pressure to give sodium phenate, which on acidification liberates phenol (Dow process) or the catalytic vapor-phase reaction of steam and chlorobenzene at 500°C (Raschig process). 

A certain amount of phenol, as well as the cresols, is obtained from coal tar (Sec. 12.4). Most of it (probably over 90%) is synthesized. One of the synthetic processes used is the fusion of sodium benzenesulfonate with alkali (Sec. 30.12) another is the Dow process, in which chlorobenzene is allowed to react with aqueous sodium hydroxide at a temperature of about 360°. Like the synthesis of aniline from chlorobenzene (Sec. 22.7), this second reaction involves nucleophilic substitution under conditions that are not generally employed in the laboratory (Sec. 25.4). 

Inhibiting Side Reactions. As stated in a preceding section, undesired by-product sulfone formation is pronounced in the mono- and disulfonation of ai matic hydrocarbons such as benzene, toluene, or xylene with SO or strong oleum. The addition of acetic acid (about 5 per cent by weight of the hydrocarbon) inhibits, but does not eliminate, sulfone formation. Sodium sulfate and sodium benzenesulfonate are also said to inhibit sulfone formation from benzene. In sul nating dodecylbenzene detergent alkylate with SO3, sulfone formation does not occur as it does with benzene or toluene, but sulfonic anhydride formation does occur. This objection-... 

Reaction of benzenesulfonic acid with sodium hydroxide... 

Another S jAr reaction heats benzenesulfonic acid (42) with aqueous sodium hydroxide (to 300°C) in a reaction bomb. The fastest reaction is the deprotonation of the acid by hydroxide to give sodium benzenesulfonate (152), an acid-base reaction with the acidic phenol 152 reacts with hydroxide to give the resonance-stabilized carbanionic intermediate, 153. Loss of sodium sulfite (Na2S03) gives phenoxide, 154. Cooling the reaction and neutralization with acid give phenol, 19. 

Arynes combine with all kinds of polar compounds such as lithium halide, alcohols, primary, secondary or tertiary amines, phosphines, and boranes. Of practical, even technical, importance are their reactions with metal hydroxides and alkoxides. The conversion of chlorobenzene by sodium hydroxide at 350 °C into sodium phenolate, an industrial process, obeys the elimination/addition mechanism. Again arynes can be postulated as plausible intermediates. Regardless of which isomer of bromophenol or of bromophenyl benzenesulfonate is heated with sodium hydroxide, resorcinol is always isolated as the main or sole product after neutralization. 

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