Cellulose structural formula

Fig. 6.2 Structural formulas of cellulose (a), example of hemicelluloses (b), and an example of lignin (c), showing a repeating unit as possible model compound.

Draw structural formulas comparing starch with cellulose. 

Therapeutic Function Topical protectant, Ophthalmic vehicle Chemical Name Cellulose 2-hydroxypropyl ether Common Name Hyprolose Structural Formula ... 

From the evidence presented, the structural formula of native cellulose may be schematically represented as in Fig. 2, neglecting for the moment the concepts of cross linking, and the fact that by common usage of the term, a cellulosic fiber material containing no detectable, or many, end groups is still called cellulose. 

The end-group method was applied to the determination of the molecular weight of cellulose by Haworth and others. The structural formula for cellulose is discussed in Chapter 3. The two end groups have the structures... 

Concerning the structural formula for cellulose, Esselen says, Cellulose chemists for the most part have been agreed for some time that cellulose contained three hydroxyl groups and no more, but whether these were primary, secondary, or tertiary was not known. Denham and Woodhouse recently answered this question very prettily by repeated treatments of cellulose with dimethyl sulphate in the presence of alkali. On hydrolyzing with weak acid they obtained chiefly trimethyl dextrose, which may be represented. 

The cellulose chemical formula is C Hj Og. The widely accepted macromolecu-lar structure of cellulose is given in Figure 17.1. The glucose base units are... 

In all these studies, microcrystalline cellulose was used as the solid powdered substrate. The structural formula of cellulose is presented in Figure 18. 

FIGURE 28.3 Structural formula of cellulose acetate phthalate. (From Builders, P.F. and Attama, A.A., Functional properties of biopolymers for drug delivery applications, in Biodegradable Materials, Johnson, B.M. and Berkel, Z.E., Eds., Nova Science Publishers Inc., New York. Copyright 2011, with permission from Nova Science Publishers, Inc.)... 

Rings similar to those of rubber were then proposed for numerous organic colloids. For example, the structural formula for cellulose (see Section 31.5) was written as... 

Figure 6.8. Structure of cellulose A, Structural formula for cellulose B, intermolecular hydrogen bonded cellulose chains C, structure of cellulose microfibrils, from ref. [50] and reprinted by permission of the authors and publisher.

The macromolecular nature of cellulose was proposed by Staudinger in 1920. Today it is generally accepted that cellulose occurs in nature as an unbranched macromolecule with structural formula (1). The values of x (number of cellobiose units) range as high as 2000-2500. The molecular... 

Cellulose and starch are macromolecules with empirical formulas that resemble hydrated carbon, CX (H2 0)y, where x and y are integers. The monomers from which these macromolecules are consfructed are sugars such as glucose and fructose. These monomers and macromolecules are the carbohydrates. Structurally, carbohydrates are very different from simple combinations of carbon and water. Even the smallest carbohydrates contain carbon chains with hydrogen atoms, OH groups, and occasional ether linkages. 

Scarcely had the covalent chain concept of the structure of high polymers found root when theoretical chemists began to invade the field. In 1930 Kuhn o published the first application of the methods of statistics to a polymer problem he derived formulas expressing the molecular weight distribution in degraded cellulose on the assumption that splitting of interunit bonds occurs at random. 

Both inorganic and organic sorbent materials are suitable for apphcation in partition PLC. The relevant material in this connection is cellulose. Celluloses are natural products with the universal chemical formula (CgHioOj),. These native celluloses have a fibrous structure and they need to be groimd and purified before use in PLC. Besides native cellulose, microcrystalline cellulose can also be used in partition PLC. In this case the cellulose has been recrystaUized and is rod-shaped. The specific surface area of celluloses is in the range of about 2 m /g. 

Carbohydrates were first analyzed in the early nineteenth century and described as compounds that were literally hydrates of carbon because they had the general formula CX(H20)X. In recent years, carbohydrate molecules are generally classified on the basis of their structures, not their formulas. Among the compounds that belong to this family are cellulose, starch, glycogen, and most sugars. 

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