Sulfuric acid reaction with sugar

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). 

The total content of RNA + DNA in tissues may be estimated from the phosphorus content or by color reactions of the sugars.37 545 These reactions depend upon dehydration to furfural or deoxyfurfural by concentrated sulfuric acid or HC1 (Eq. 4-4). Furfural formed from RNA reacts with orcinol (3,5-dihydroxy-toluene) and ferric chloride to produce a green color useful in colorimetric estimation of RNA. A similar reaction of DNA with diphenylamine yields a blue color. 

Uronic acids were traditionally measured by the carbazole reaction. In this procedure, sugars were treated with concentrated sulfuric or hydrochloric acid to yield products that reacted with carbazole. For example, Dische (1947) used carbazole for the determination of uronic acid in solutions of sulfuric acid, but the method was subject to interference from neutral sugars that were also present in the solution. The... 

Post-column derivatization of carbohydrates has been described for liquid chromatography and UV detection by heat treatment [46], acid treatment [47] and reaction with phenol-sulfuric acid [48,49]. These methods have been applied to the analysis of sugars in body fluids and in wood products. The procedures are only suitable for low-speed liquid chromatography. 

In perchloric acid, hexoses and pentoses are oxidized by Ce(IV) via formation of two complex intermediates. The first is partly oxidized following Michaelis-Menten kinetics and partly dissociated to the second, which is oxidized more slowly than the former.180 The first step in the oxidation of aldoses by Tl(III) in the same medium involves the C-l-C-2 cleavage of the aldehydo form of the sugar. Thus, D-glucose gives D-arabinose and formic acid. With an excess of oxidant the final product is carbon dioxide.181 In the presence of a catalytic amount of sulfuric acid in acetic acid, Tl(III) oxidizes maltose and lactose to the corresponding disaccharide aldonic acids. The reaction showed activation enthalpies and enthropies characteristic of second-order reactions.182... 

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