Toluenesulfonic acids

Colorless monoclinic leaflets or prisms crystalline solid mp (anhydrous), 106-107°C bp20, 140°C.1,2 

When heated to decomposition, emits highly toxic fumes of sulfur dioxide.3 

Acetic Acid, Acetic Anhydride, and Water. Explosions can occur when using an analytical method involving sequential addition of acetic acid, aqueous / -toluenesulfonic acid, and acetic anhydride to serum.4 

Irritating to the skin, eyes, and mucous membranes.2 Highly toxic if swallowed. Animal experiments show moderate systemic toxicity and high irritation.3 

Wear eye protection, laboratory coat, and nitrile rubber gloves. Scoop into a pail of cold water. Neutralize with sodium carbonate and wash into the drain.2 

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In the flask were placed 1.50 mol of the isopropenyl ether (conmercially available) and 0.10 mol of the (dry) acetylenic alcohol (also commercially available), and in the dropping funnel 0.4 mol of the latter compound. The mixture was cooled to 0°C and 100 mg of anhydrous p-toluenesulfonic acid were added with stirring. 

Reaction of benzaldehyde with 1 2 octanediol in benzene containing a small amount of p toluenesulfonic acid yields almost equal quantities of two products in a combined yield of 94% Both products have the molecular formula C15H22O2 Suggest reasonable structures for these products... 

Aqueous caprolactam is polymerized alone and in the presence of sebacic acid (S) or hexamethylenediamine (H).t After a 24-hr reaction time, the polymer is isolated and the end groups are analyzed by titrating the carboxyl groups with KOH in benzyl alcohol and the amino groups with p-toluenesulfonic acid in trifluoroethanol. The number of milliequivalents of carboxyl group per mole caprolactam converted to polymer, [A ], and the number of milliequivalents of amino groups per mole caprolactam converted to polymer, [B ], are given below for three different runs ... 

Acylated Corticoids. The corticoid side-chain of (30) was converted iato the cycHc ortho ester (96) by reaction with a lower alkyl ortho ester RC(OR )2 iu benzene solution ia the presence of i ra-toluenesulfonic acid (88). Acid hydrolysis of the product at room temperature led to the formation of the 17-monoesters (97) ia nearly quantitative yield. The 17-monoesters (97) underwent acyl migration to the 21-monoesters (98) on careful heating with. In this way, prednisolone 17a,21-methylorthovalerate was converted quantitatively iato prednisolone 17-valerate, which is a very active antiinflammatory agent (89). The iatermediate ortho esters also are active. Thus, 17a,21-(l -methoxy)-pentyhdenedioxy-l,4-pregnadiene-liP-ol-3,20-dione [(96), R = CH3, R = C Hg] is at least 70 times more potent than prednisolone (89). The above conversions... 

Acetic anhydride acetylates free hydroxyl groups without a catalyst, but esterification is smoother and more complete ia the presence of acids. For example, ia the presence of -toluenesulfonic acid [104-15-4], the heat of reaction for ethanol and acetic anhydride is —60.17 kJ/mol (—14.38 kcal/mol) (13) ... 

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. 

Polyhydric alcohol mercaptoalkanoate esters are prepared by reaction of the appropriate alcohols and thioester using -toluenesulfonic acid catalyst under nitrogen and subsequent heating (16,17). Organotin mercapto esters are similarly produced by reaction of the esters with dibutyltin oxide (18). Pentaerythritol can be oxidized to 2,2-bis(hydroxymethyl)hydracryhc acid [2831-90-5] C H qO, ... 

H2SnClg 6H20, CISO H + CH OH, CH COOH, as well as ben2ene-, naphthalene-, and -toluenesulfonic acids (44). Zinc chloride is probably the most frequentiy used catalyst. Its activity is sometimes increased by fusion with a small amount of aluminum chloride. In other instances, however, sufficient catalytic effect is obtained with a mineral acid alone. 

Isophorone usually contains 2—5% of the isomer P-isophorone [471-01-2] (3,5,5-trimethyl-3-cyclohexen-l-one). The term a-isophorone is sometimes used ia referring to the a,P-unsaturated ketone, whereas P-isophorone connotes the unconjugated derivative. P-lsophorone (bp 186°C) is lower boiling than isophorone and can be converted to isophorone by distilling at reduced pressure ia the presence of -toluenesulfonic acid (188). Isophorone can be converted to P-isophorone by treatment with adipic acid (189) or H on(Ill) acetylacetoate (190). P-lsophorone can also be prepared from 4-bromoisophorone by reduction with chromous acetate (191). P-lsophorone can be used as an iatermediate ia the synthesis of carotenoids (192). 

Catalysts. The alkanolamines continue to find use as blocked catalysts for textile resins, coatings resins, adhesives, etc. Of particular utifity in curing durable-press textiles is AMP-HCl. Other salts, such as those of the benzoin tosylate or A-toluenesulfonic acid, find utifity in melamine- or urea-based coatings (18) (see Amino resins and plastics). 

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). 

Mixtures of /V-alkylanilines can usually be separated by fractional distillation. Mixtures of the methyl or ethyl derivatives have also reportedly been separated by converting the V/-ethyl or the /V-methyl derivative to the nonvolatile salt with -toluenesulfonic acid (12) or phthaUc anhydride (13), followed by distillation. 

These precursors are prepared by reaction of fuming nitric acid in excess acetic anhydride at low temperatures with 2-furancarboxaldehyde [98-01-1] (furfural) or its diacetate (16) followed by treatment of an intermediate 2-acetoxy-2,5-dihydrofuran [63848-92-0] with pyridine (17). This process has been improved by the use of concentrated nitric acid (18,19), as well as catalytic amounts of phosphoms pentoxide, trichloride, and oxychloride (20), and sulfuric acid (21). Orthophosphoric acid, -toluenesulfonic acid, arsenic acid, boric acid, and stibonic acid, among others are useful additives for the nitration of furfural with acetyl nitrate. Hydrolysis of 5-nitro-2-furancarboxyaldehyde diacetate [92-55-7] with aqueous mineral acids provides the aldehyde which is suitable for use without additional purification. 

Specifically MSA has been found to be more effective than -toluenesulfonic acid and sulfuric acid in preparing dioctyl phthalate (405). A U.S. patent also discloses its use to prepare light-colored fatty esters (406). It is also important as a catalyst to prepare acrylates, methacrylates, adipates, phthalates, trimeUitates, thioglycolates, and other esters. 

Reaction of carboxylate ion with nitrophenyl sulfites gives the carboxylate -nitrophenyl esters. If the -nitrophenyl sulfite is unsymmethcal (02NCgH40S(0)0R, where R is ethyl or phenyl), carboxylate attacks the -nitrophenyl side (69). Some amino acids react with methyl and benzyl sulfites in the presence of -toluenesulfonic acid to give methyl and benzyl esters of the amino acids as -toluenesulfonate salts (70). With alcohols, the conversion of henzil to a monoacetal upon addition of sulfuric acid to the henzil in methanol and dimethyl sulfite proceeds in high yield (71). 

In plasticizer manufacture, eg, of phthalates or sebacates, uskig sulfuric or/ -toluenesulfonic acid catalysts, the temperature (140—150°C) requked for rapid reaction and high conversion may dehydrate or oxidize the alcohol and may yield a dark or foul-smelling product. Neutral titanates do not cause such side reactions. Although a temperature of 200°C is requked, esterifications can easily be forced to over 99% conversion without the formation of odors or... 

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). 

The starting materials of the aldehyde method may be sulfonated. For example. Cl Acid Blue 9 [2650-18-2] Cl Food Blue 2 (Cl 42090), is manufactured by condensing a-(A/-ethylanilino)-y -toluenesulfonic acid with o-sulfobenzaldehyde. The leuco base is oxidized with sodium dichromate to the dye, which is usually isolated as the ammonium salt. In this case, the removal of the excess amine is not necessary. However, this color caimot be used in the food sector because separation of the chromium compounds from the dye is difficult. An alternative method which gives food-grade Cl Acid Blue 9 (14) and dispenses with the use of sodium dichromate employs oxidative electrolysis of the leuco base (49). 

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