Anhydrides, mixed sulfuric acid

Phenolphthalein. Alophen, Ex-Lax, Feen-a-Miat, Modane, and Phenolax are trade names for phenolphthaleia [77-09-8] (3,3-bis(4-hydroxyphen5l)-l-(3ff)-l isobensofuranone) (10). It is a white or faintiy yellowish white crystalline powder, odorless and stable ia air, and practically iasoluble ia water one gram is soluble ia 15 mL alcohol and 100 mL diethyl ether. Phenolphthaleia may be prepared by mixing phenol, phthaHc anhydride, and sulfuric acid, and heating at 120°C for 10—12 h. The product is extracted with boiling water, then the residue dissolved ia dilute sodium hydroxide solution, filtered, and precipitated with acid. 

It should be borne in mind in these cases that while mixed acetic anhydride and sulfuric acid produce acetylation, they also bring about acetolysis which may result in severe depolymerization of the starch molecules. The occurrence of degradation is evident from the fact that the resulting acetates have acetyl values in excess of the theoretical value of 44.78%, and from the finding of glucose pentaacetate among the reaction products whenever low temperatures or low sulfuric acid concentrations are not employed. 

XYLIDINE, MIXED ISOMERS (1300-73-8) Combustible liquid (flash point 205°F/96°C). Violent reaction with strong oxidizers, strong acids, nitrosyl perchlorate. Mixtures with hypochlorites form sensitive explosive chloroamines. Incompatible with aldehydes, nonoxidizing mineral acids, cellulose nitrate (of high surface area), cresols, isocyanates, nitrates, nitric acid, organic anhydrides, phenols, sulfuric acid. 

The other key precaution is the need to maintain strictly anhydrous conditions in both the production of the SO -solvent complex, and the reaction of that complex with the lysergic acid salt to produce the mixed anhydride. The reason for this is that SO3 is the anhydride of sulfuric acid, and any traces of moisture will react with it to produce sulfuric acid. Sulfuric acid does not react with lysergic acid to form an anhydride. Instead, it just messes up the stoichiometry of the reaction, leading to greatly reduced yields. 

In the development of mixed anhydrides the year 1951 was indeed an annus mirabilis . In England G.W. Kenner (Plate 27) invented the interesting and efficient method of peptide bond formation via anhydrides of acylamino acids with sulfuric acid [12]. The reactive intermediates prepared from the blocked amino acid and the anhydride of sulfuric acid applied in the form of a complex... 

Fluorosulfuric acid [7789-21-17, HSO F, is a colodess-to-light yellow liquid that fumes strongly in moist air and has a sharp odor. It may be regarded as a mixed anhydride of sulfuric and hydrofluoric acids. Fluorosulfuric acid was first identified and characterized in 1892 (1). It is a strong acid and is employed as a catalyst and chemical reagent in a number of chemical processes, such as alkylation (qv), acylation, polymerization, sulfonation, isomerization, and production of organic fluorosulfates (see Friedel-CRAFTSreactions). 

Other mixed esters, eg, cellulose acetate valerate [55962-79-3] cellulose propionate valerate [67351-41-17, and cellulose butyrate valerate [53568-56-2] have been prepared by the conventional anhydride sulfuric acid methods (25). Cellulose acetate isobutyrate [67351-38-6] (44) and cellulose propionate isobutyrate [67351-40-0] (45) have been prepared with a 2inc chloride catalyst. Large amounts of catalyst and anhydride are required to provide a soluble product, and special methods of delayed anhydride addition are necessary to produce mixed esters containing the acetate moiety. Mixtures of sulfuric acid and perchloric acid are claimed to be effective catalysts for the preparation of cellulose acetate propionate in dichi oromethane solution at relatively low temperatures (46) however, such acid mixtures are considered too corrosive for large-scale productions. 

A suspension of 40 g 3-acetylaminomethyl-5-amino-2,4,6-triodobenzoic acid in 180 ml acetic anhydride were mixed with 0.4 ml concentrated sulfuric acid. An exothermic reaction was thereby initiated. Acetylation was completed by heating to 80°C for three hours. The reaction mixture was then evaporated to dryness in a vacuum at a temperature not exceeding 50°C. The residue was treated with a mixture of 30 ml concentrated aqueous ammonium hydroxide and 40 ml water, whereby the solid material dissolved with spontaneous heating. Within a few minutes, the ammonium salt of the acetylated product started precipitating. The precipitate and residual liquid were cooled externally with ice after about 15 minutes. The salt was separated from the liquid by filtration with suction, and was washed with ice cold saturated ammonium chloride solution. 

An important role must be attributed to intermediate mixed anhydrides of sulfonic acids and mineral acids sulfonic acid anhydrides are reported to need Friedel-Crafts conditions to generate sulfones327,476. Instead of arenesulfonic acids, their methyl esters may undergo insertion of sulfur trioxide477,478 yielding mixed anhydrides, which in turn furnish... 

In the first step an S03 molecule is inserted into the ester binding and a mixed anhydride of the sulfuric acid (I) is formed. The anhydride is in a very fast equilibrium with its cyclic enol form (II), whose double bonding is attacked by a second molecule of sulfur trioxide in a fast electrophilic addition (III and IV). In the second slower step, the a-sulfonated anhydride is rearranged into the ester sulfonate and releases one molecule of S03, which in turn sulfonates a new molecule of the fatty acid ester. The real sulfonation agent of the acid ester is not the sulfur trioxide but the initially formed sulfonated anhydride. In their detailed analysis of the different steps and intermediates of the sulfonation reaction, Schmid et al. showed that the mechanism presented by Smith and Stirton [31] is the correct one. 

The mixed sulfuric phosphoric anhydride (PAdoPS or PAPS) of 3 -phospho-5 -adenylic acid is named as an acyl sulfate ... 

Entry 5 is an example of nitration in acetic anhydride. An interesting aspect of this reaction is its high selectivity for the ortho position. Entry 6 is an example of the use of trifluoroacetic anhydride. Entry 7 illustrates the use of a zeolite catalyst with improved para selectivity. With mixed sulfuric and nitric acids, this reaction gives a 1.8 1 para ortho ratio. Entry 8 involves nitration using a lanthanide catalyst, whereas Entry 9 illustrates catalysis by Sc(03SCF3)3. Entry 10 shows nitration done directly with N02+BF4, and Entry 11 is also a transfer nitration. Entry 12 is an example of the use of the N02—03 nitration method. 

In a 300-ml. Claisen flask, whose side neck is elongated by a 10-cm. indented section, 102 g. (1 mole) of acetic anhydride and 0.1 ml. (Note 1) of concentrated sulfuric acid are mixed by hand swirling. The mixture is cooled to 10° by swirling in an ice bath, then there is added, during about 10 minutes, 96 g. (1 mole) of recently distilled furfural (Note 2). The temperature is maintained at 10-20°. After addition is complete and the contents of the flask have been well mixed by swirling, the cooling bath is removed and the reaction allowed to warm up spontaneously. A maximum temperature of about 35° is usually reached in about 5 minutes. After the temperature has dropped to that of the room (20-30 minutes), 0.4 g. (Note 1) of anhydrous sodium... 

Di- -octylphthalate is produced commercially as a component of mixed phthalate esters, including straight-chain C6, C8, and CIO phthalates (EPA 1993a). Di- -octylphthalate is produced at atmospheric pressure or in a vacuum by heating an excess of w-octanol with phthalic anhydride in the presence of an esterification catalyst such as sulfuric acid or / -tolucncsul Tonic acid. The process may be either continuous or discontinuous (EPA 1993a HSDB 1995). Di- -octylphthalate can also be produced by the reaction of -octylbromide with phthalic anhydride. 

Initial nitration of pyrazole derivatives with nitric acid in acetic or trifluoroacetic anhydrides leads to A-nitropyrazoles, which rearrange to the C-nitrated product on stirring in concentrated sulfuric acid at subambient temperature. This N -> C nitro group rearrangement often occurs in situ when pyrazoles are nitrated with mixed acid. 

Mannitol hexanitrate is obtained by nitration of mannitol with mixed nitric and sulfuric acids. Similarly, nitration of sorbitol using mixed acid produces the hexanitrate when the reaction is conducted at 0—3°C and at —10 to —75°C, the main product is sorbitol pentanitrate (117). Xylitol, ribitol, and L-arabinitol are converted to the pentanitrates by fuming nitric acid and acetic anhydride (118). Phosphate esters of sugar alcohols are obtained by the action of phosphorus oxychloride (119) and by alcoholysis of organic phosphates (120). The 1,6-dibenzene sulfonate of D-mannitol is obtained by the action of benzene sulfonyl chloride in pyridine at 0°C (121). To obtain 1,6-dimethanesulfonyl-D-mannitol free from anhydrides and other by-products, after similar sulfonation with methane sulfonyl chloride and pyridine the remaining hydroxyl groups are acetylated with acetic anhydride and the insoluble acetyl derivative is separated, followed by deacetylation with hydrogen chloride in methanol (122). Alkyl sulfate esters of polyhydric alcohols result from the action of sulfur trioxide—trialkyl phosphates as in the reaction of sorbitol at 34—40°C with sulfur trioxide—triethyl phosphate to form sorbitol hexa(ethylsulfate) (123). 

Nitration of 4,7-phenanthroline has been accomplished,252 thus disproving old statements that it cannot be so substituted. By using mixed nitric and sulfuric acids at 170°, a 17% yield of 5-nitro-4,7-phen-anthroline was obtained. If nitric acid in acetic anhydride is used as the nitrating medium, 2-nitro-4,7-phenanthroline is the product, albeit in low yield. 

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