title: Determination of the optimal reaction conditions for the preparation of highly substituted carboxymethyl Cassia tora gum.
abstract: Highly substituted carboxymethyl Cassia tora gum (CM-CTG) was prepared from CTG by treatment with monochloroacetic acid (MCA) in ethanolic aqueous solutions after alkalization under different reaction conditions. The influence of the etherification temperature, alkalization and etherification times, molar ratio of sodium hydroxide to MCA (nNaOH/nMCA), theoretical degree of substitution (DSt), and weight percentage of water (WH2O%) in the solution on the degree of substitution (DS) and reaction efficiency (RE) of the reaction were investigated. Optimum preparation conditions for a CM-CTG with DS of 1.05 are: etherification temperature, 60°C; alkalization time, 60min; etherification time, 180min; nNaOH/nMCA, 2.1; DSt, 1.4; and WH2O%, 20%. Fourier-transform infrared analysis of the products indicated that carboxymethylation was successful. Rheological studies show that all the CM-CTG pastes are pseudoplastic fluids, and the shear sensitivity varies with DS. The degree of crystallinity of CM-CTG decreases with increasing DS, as shown by X-ray diffraction measurements.
authors.affiliation: Textile School, Zhongyuan University of Technology, Zhengzhou 450007, Henan Province, China; Zhongyuan University of Technology Science Park, Zhengzhou 450007, Henan Province, China.
authors.forename: Zongwen
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Textile School, Zhongyuan University of Technology, Zhengzhou 450007, Henan Province, China; Zhongyuan University of Technology Science Park, Zhengzhou 450007, Henan Province, China. Electronic address: freedomzpw@126.com.
authors.forename: Peiwen
authors.initials: P
authors.lastname: Zhou
authors.affiliation: Textile School, Zhongyuan University of Technology, Zhengzhou 450007, Henan Province, China; Zhongyuan University of Technology Science Park, Zhengzhou 450007, Henan Province, China.
authors.forename: Jingru
authors.initials: J
authors.lastname: Yang
authors.affiliation: Textile School, Zhongyuan University of Technology, Zhengzhou 450007, Henan Province, China; Zhongyuan University of Technology Science Park, Zhengzhou 450007, Henan Province, China.
authors.forename: Junli
authors.initials: J
authors.lastname: Li
mesh_terms: D002366:Cassia / Q000737:chemistry*; D053149:Plant Gums / Q000737:chemistry*; D012972:Sodium Hydroxide; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D053149:Plant Gums; D012972:Sodium Hydroxide
keywords: Carboxymethyl Cassia tora gum; D-Glucopyranose (PubChem CID: 5793); D-Mannopyranose (PubChem CID: 18950); Degree of substitution; Monochloroacetic acid (PubChem CID: 300); Non-newtonian fluids; Printing pastes; Reaction efficiency; Sodium diglycolate (PubChem CID: 517059); Sodium glycolate (PubChem CID: 517347); Sodium monochloroacetate (PubChem CID: 23665759)