An explanation of increased hydrolysis of the β-(1,4)-glycosidic linkages of grafted cellulose using molecular modeling

Abstract

Grafting various groups onto cellulose is found to substantially increase acid hydrolysis of the b-(1,4)-glycosidic linkages. Molecular modeling is used to explain how various substituents such as esters and ethers cause this phenomenon. A substituent helps stabilize hydrolyzed cellulose by serving as an anchor to the end of the cleaved cellulose to which it is bonded, making it less mobile, and allowing it to have stronger interactions than those in pure hydrolyzed cellulose. Hydrolysis increases with increasing size of the substituent. Molecules sorbed but not grafted to cellulose do not increase hydrolysis. Hydrolysis mainly occurs at glucoses bonded to the substituent, and supporting experiments show that hydrolysis approaches equilibrium when no substituent remains on the cellulose fiber.

Effect of Structure of Large Aromatic Molecules Grafted onto Cellulose on Hydrolysis of the Glycosidic Linkages

“…Most of the substituents included in this study were aliphatic except one with a phenol group and one small reactive dye. [7] The purpose of this study was to explain the effect of the structure of large aromatic molecules substituted onto cellulose on hydrolysis of the glycosidic linkages of cellulose. Reactive dyes were selected as the substituents in this study since cellulose fiber is commonly dyed with reactive dyes, and their effect on hydrolysis of the glycosidic linkages is, therefore, important.…”

“…Another reason these substituents were selected is that, compared to those included in an earlier study on the hydrolysis of substituted cellulose, the substituents in this study are larger aromatic molecules while those in the earlier study were mainly smaller aliphatic molecules. [7] Experimental Part…”

“…[7,[11][12][13][14] The molecular modeling software MS Modeling 3.0, available from Accelrys, was used. [15] An amorphous structure of cellulose was built using the Amorphous Cell module of MS Modeling 3.0.…”

“…[2][3][4][5] Cellulose grafted to another molecule has been shown to be hydrolyzed to a greater extent compared to nonderivatized cellulose. [6][7][8][9][10] This phenomenon is important to consider since cellulose derivatives such as cellulose acetate and carboxymethylcellulose, and grafted cellulose such as reactive dyed cellulose, have important uses. One theory is that a substituent on the glucose residual on the right side of the glycosidic linkage increases hydrolysis of the glycosidic linkage by inducing the transfer of…”

Method for predicting sorption of small drug molecules onto polylactide

“…The molecular modeling software MS Modeling 3.0, available from Accelrys, was used. 43 An amorphous PLA structure was built according to the methodology used in previous studies to build amorphous structures of cellulose 44,45 or amorphous structures of PLA. 46,47 The Amorphous Cell module of MS Modeling 3.0 was used to build a PLA structure that consisted of 10 poly(L-lactide) chains with a degree of polymerization of 50 and a density of 1.27 g/cm 3 .…”