Toluene Toluenesulfonic acid

Methylphenol. T -Cresol is produced synthetically from toluene. Toluene is sulfonated to yield T i ra-toluenesulfonic acid, which is then converted to 4-methylphenol via the caustic fusion route. A minor amount of 4-methylphenol is also derived from petroleum cmde and coal tars. 4-Methylphenol [106-44-5] is available in 55-gal dmms (208-L) and in bulk quantities as a molten material. 

Refluxing linoleic acid and a primary or secondary alkyl amine with -toluenesulfonic acid in toluene for 8—18 h also yields the substituted amides (32—34). The reaction of methyl esters with primary or secondary amines to make substituted amides is catalyzed with sodium methoxide. Reactions are rapid at 30°C under anhydrous conditions (35). Acid chlorides can also be used. Ai,A/-dibutyloleamide [5831-80-17 has been prepared from oleoyl chloride and dibutyl amine (36). 

Toluenesulfonic Acid. Toluene reacts readily with fuming sulfuric acid to yield toluene—sulfonic acid. By proper control of conditions, /)i7n7-toluenesulfonic acid is obtained. The primary use is for conversion, by fusion with NaOH, to i ra-cresol. The resulting high purity i7n -cresol is then alkylated with isobutylene to produce 2 (i-dii-tert-huty -para-cmso (BHT), which is used as an antioxidant in foods, gasoline, and mbber. Mixed cresols can be obtained by alkylation of phenol and by isolation from certain petroleum and coal-tar process streams. 

The toluenesulfonic acid prepared as an iatermediate ia the preparation ofpara-cmso also has a modest use as a catalyst for various esterifications and condensations. Sodium salts of the toluenesulfonic acids are also used ia surfactant formulations. Annual use of toluene for sulfonation is ca 100,000-150,000 t (30-45 x 10 gal). 

Toners derived from 6-chlorometanilic acid [88-43-7] 6-amiao-4-chloro-y -toluene-sulfonic acid [88-51-7] and 6-arriino-y -toluenesulfonic acid [88-44-8] have improved fastness properties and find use in paints, inks, and plastics. 

The conjugated enone (177) is treated withp-toluenesulfonic acid in refluxing toluene to form the more stable product (178). The A -17-keto-system is formed by acid catalyzed cleavage of the A -17-ketal (see page 304), but the conditions are not drastic enough to cause equihbration to the more stable A " -compound. (The latter may be ketalized to form the A -17-ketal.) ... 

An improved yield of ketal is obtained by heating a solution of 2 g of progesterone in 16 ml of ethylene glycol and 70 ml of toluene containing 65 mg of / -toluenesulfonic acid monohydrate at reflux for 4 hr. The yield of bisethy-lene ketal is 1.34 g (67%), mp 178-182°. 

A recent report demonstrates that trisubstituted furans can be prepared on a solid support using the Paal-Knorr condensation. Raghavan synthesized a variety of triaryl and alkyl diary] furans, one of which is highlighted below. Dione 50 was cyclized using p-toluenesulfonic acid in refluxing toluene followed by cleavage from the solid support to yield furan 51. ... 

A 250-ml round-bottom flask is charged with a mixture of cyclohexanone (14.7 g, 0.15 mole), morpholine (15.7 g, 0.18 mole), and / -toluenesulfonic acid monohydrate (0.15 g) in 50 ml of toluene. The flask is fitted with a water separator and a condenser and is brought to reflux (mantle). The separation of water begins immediately and the theoretical amount (2.7 ml) is obtained in about 1 hour. Without further treatment, the reaction mixture may then be distilled. After removal of the toluene at atmospheric pressure, the product is obtained by distillation at reduced pressure, bp II8-I207IO mm, 1.5122-1.5129, in about 75% yield. 

In contrast to the A-sulfonyl derivatives, Ar-acylcyclohexadienamines 5, on treatment with p-toluenesulfonic acid in toluene at 20 C, yield 3 a,7a-dihydrobenzoxazoles 6 rather than 1-substituted 1//-azepines.21 However, the dihydrobenzoxazoles 6 are thermally unstable and on heating at 180X rearrange smoothly to the 1-acyl-l//-azepines 7 in high yields. 

The following section describes as an example the sulfonation of toluene to />-toluenesulfonic acid. Concerning the formation of byproducts, see page 81. Figure 24 gives an overview of the process [162]. The maunufacture of p-toluenesulfonic acid follows continuously by the conversion of alkylbenzene with 96-100% sulfuric acid in the mixing vessel Rl. The formed water is re-... 

Thiol protection, 59, 190 Thiono esters, reaction with ethyl isocyanoacetate, 59,187 Thionyl chloride, 55, 27 Thiophenol, 55, 122 58, 144 Thorium dodecanedioate, 56,110 Toluene, 56, 86 58,125 p-Toluenesulfonates, reaction with organo-cuprates, 55,112 p-Toluenesulfonic acid, 58, 57, 63 p-Toluenesulfonic acid, monohydrate, 56,44... 

In an effort to form the dimer as the major product and to determine what effect the temperature of reaction had on the ratio of HMI to LMI, the hydroxybutenolide XVII was heated to reflux in benzene (bp = 80.1°C), toluene (bp = 110.6°C), and xylene (mixture bp = 137-144°C) in the presence of catalytic p-toluenesulfonic acid... 

With carboxylic acids there was no activation to carboxylic acid imidazolides observed. Reaction with p-toluenesulfonic acid in boiling tetrahydrofuran did not yield the />-toluenesulfonic acid imidazolide, but rather the double p-toluene sulfonate, from which A -sulfonyldiimidazole can be released again quantitatively with imidazole or aniline. Only from the melt of water-free p-toluenesulfonic acid and AyV -sulfonyldiimidazole at 90 °C p-toluenesulfonic imidazolide (m.p. 75.5-77 °C 87% yield) could be obtained1201 (see also Section 10.1.1). 

The preparation of imines, enamines, nitroalkenes and N-sulfonylimines proceeds via the azeotropic removal of water from the intermediate in reactions that are normally catalyzed by p-toluenesulfonic acid, titanium(IV) chloride, or montmorillonite K 10 clay. A Dean-Stark apparatus is traditionally used which requires a large excess of aromatic hydrocarbons such as benzene or toluene for azeotropic water elimination. 

Cycloalkanones were reacted with diethyl aminomethylenemalonate (13) in boiling toluene or xylene in the presence of dichloroacetic acid or p-toluenesulfonic acid monohydrate under nitrogen or argon for 2.5-7 days, and under a water separator, to give N-( 1 -cycloalkenyDaminomethy-lenemalonates (275, R = R1 = —(CH,)n—, n = 6-10) (88EUP270494). 

Diethyl aminomethylenemalonate (13) was reacted with tetrahydrothio-pyran-4-one in boiling toluene for 48 hr in the presence of p-toluenesulfonic acid to give A-(thiopyran-4-yl)aminomethylenemalonate (278, X = S) (86EUP168350 87USP4647566). 

Anilines, bis(2-amino-4-chlorophenyl)disulfide, naphthylamine, 2- and 3-aminopyridines, 2-aminopyrimidines, 2-, 3-, 5-, 6-, 7-, and 8-aminoquino-lines, 6-aminocoumarin, and 2-aminopyrazine were reacted in the absence or presence of a solvent (ethanol, toluene) with ethyl orthoformate and isopropylidene or 4-heptylidene malonates to give alkylidene (het)aryl-aminomethylenemalonates (442, R = R2 = Me, Pr) in 32-100% yields [69BRP1147759 75USP3907798 88JAP(K)239269]. p-Toluenesulfonic acid monohydrate was sometimes applied as catayst. 

A continuous procedure for the alkylation of mesitylene and anisole with supercritical propene, or propan-2-ol in supercritical carbon dioxide, with a heterogeneous polysiloxane-supported solid acid Deloxan catalyst has been reported giving 100% selectivity for monoalkylation of mesitylene with 50% conversion at 250 °C and 150 bar by propan-2-ol in supercritical carbon dioxide. p-Toluenesulfonic acid monohydrate has been demonstrated as an efficient catalyst for the clean alkylation of aromatics using activated alkyl halides, alkenes or tosylates under mild conditions. Cyclohexene, for example, reacts with toluene to give 100% cyclohexyltoluenes (o m p-29 18 53) under these circumstances. 

Catalysts. Catalyst addition was weight percent on polymer solids. Solution polymers employed, for example, 2-hydroxycyclohexane-p-toluene sulfonate or Nacure 155 (King Industries, dlalkylnaphthalene disulfonic acid) as organic soluble acids. A variety of catalysts were tested with emulsion polymers, the best choice varied with base polymer hydrophobicity and functional monomer distribution. Some of these Included p-toluenesulfonic acid (PTSA), ammonium chloride,... 

The last synthesis to evolve which is due to Ito and his coworkers is interesting in that it relies on a stereospecific skeletal rearrangement of a bicyclo[2.2.2]octane system which in turn was prepared by Diels-Alder methodology (Scheme XLVIII) Heating of a toluene solution of cyclopentene 1,2-dicarboxylic anhydride and 4-methylcyclohexa-l,4-dienyl methyl ether in the presence of a catalytic quantity of p-toluenesulfonic acid afforded 589. Demethylation was followed by reduction and cyclization to sulfide 590. Desulfurization set the stage for peracid oxidation and arrival at 591. Chromatography of this intermediate on alumina induced isomerization to keto alcohol 592. Jones oxidation afforded diketone 593 which had earlier been transformed into gymnomitrol. 

The reaction from an enamine is initiated by the addition of a trace of a strong acid, e.g. /7-toluenesulfonic acid (TsOH, 4-methylbenzene-sulfonic acid), to the ketone and pyrrolidine in a solvent such as toluene. When the mixture is at reflux in a Dean-Stark apparatus, water is liberated and is removed through azeotropic distillation, leaving the enamine in the reaction vessel. After a follow-up reaction between the enamine and a suitable electrophile, an iminium salt is produced that liberates both the a-substituted ketone and pyrrolidine when it is treated with aqueous acid (Scheme 6.20). 

South described the protection of 4,5-dichloropyridazin-3(2//)-one as a 2-tetrahydropyranyl derivative. The pyr-idazinone is treated with 3,4-dihydro-2/7-pyran in the presence of /)-toluenesulfonic acid or pyridinium -toluene-sulfonate in refluxing tetrahydrofuran <1995JHC1473>. The deprotection is discussed in Section 8.01.8.1. 

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