Alcohols, acetylation color reactions

Chitosan is insoluble in water, concentrated acids, alkalis, alcohol, and acetone, but dissolves readily in dilute acids. Water-soluble salts of chitosan include the nitrate and the perchlorate. As described on p. 377, formation of chitosan sulfate and the color reaction of chitosan with iodine have been widely used as qualitative tests for the detection of chitin. Nitration of chitosan with a mixture of acetic and nitric acids or with absolute nitric acid enabled both the free ester and its nitrate salt to be isolated. The perchlorate salt of this ester was also prepared, but it was unstable. Chitosan can be W-acetylated to give products similar to chitin except for their greatly reduced chain-length W-formyl-, iV-propionyl-, JV-butyryl-, and iV-benzoyl-chitosan were also prepared. ... 

The compound appears as large yellow crystals, m.p. 111°. With sodium hydroxide in alcohol an intense violet coloration is produced. With formaldehyde and sodium hydroxide in aqueous solution S7NCH2OH (m.p. 110.5°) is formed. With acetyl chloride in chloroform in the presence of pyridine reaction occurs at 0° with the formation of yellow needles of S7NCOCH3 (m.p. 104.4°). ... 

Amyloid.—When treated with concentrated sulphuric acid cellulose dissolves and undergoes hydrolysis. If the solution is diluted with water a gelatinous product is obtained which gives the blue color with iodine characteristic of starch. This product is known as amyloid. When boiled in the dilute acid the amyloid is hydrolyzed and dextrin and finally glucose are obtained. Concentrated hydrofluoric acid and phosphoric acid also dissolve cellulose. With glacial acetic acid in the presence of acetic anhydride and sulphuric acid cellulose yields acetyl derivatives indicating its alcoholic character. From the products of this reaction the acetate of a di-saccharose is obtained. 

Another method for the detection of the alcoholic group is acetylation and the reactions based on the oxidation and the formation of colored complexes. The nitrole reaction or use of the Lucas test makes the differentiation of the type of binding of the hydroxy group possible. The xantho-gcnate reaction can also be applied for sensitive detection of primary and... 

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