Determination of the degree of the substitution of hydroxyethyl guar gum

• Published in: Carbohydrate polymers Vol. 72; no. 3; pp. 557 - 560
• Main Authors: He, Ling-Sa, Jiang, Bo, Wang, Ke
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 16.05.2008; Elsevier Science
• Subjects: acetic anhydrides; acylation; Applied sciences; chemical analysis; chemical structure; chemical treatment; degree of substitution; Degree of the substitution; equations; ether cleavage rate; ethyl ether; Exact sciences and technology; guar gum; Hydroxyethyl guar gum; Mixed p-toluenesulfonic-acetic anhydride; Natural polymers; Physicochemistry of polymers; polymers; reaction kinetics; reaction mechanisms; Starch and polysaccharides; synthesis; Mixed p-toluenesulfonic-acetic anhydride; Degree of the substitution; Hydroxyethyl guar gum; Molecular structure; Chemical method; Experimental study; Sulfonic acid; Acetic anhydride; Mixed p-toluenesulfonic -acetic anhydride; Chemical modification; Guar gum(hydroxyethyl); Investigation method; Guar gum; Oside polymer
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2007.09.030

An improved chemical method for the determination of the degree of the substitution of hydroxyethyl guar gum by mixed p-toluenesulfonic-acetic anhydride has been described. The hydroxyethyl groups are cleaved from modified galactomannans at 130 °C in the presence of excess mixed p-toluenesulfonic-acetic anhydride for 14 h, and then the products hydrolyzed into ethylene glycol at pH 11 for an hour. Quantifying the mass of reaction products derived from the hydroxyethyl group, the degree of the substitution of hydroxyethyl guar gum can be precisely estimated.