Carboxymethylation, of cellulose

Sodium carboxymethyl cellulose [9004-32-4] (CMC) and hydroxyethyl cellulose [9004-62-0] (HEC) are the ceUulosics most widely used in drilling fluids (43). CMC is manufactured by carboxymethylation of cellulose which changes the water-insoluble cellulose into the water-soluble CMC (44). Hydroxyethyl cellulose and carboxymethyl hydroxyethyl cellulose (CMHEC) are made by a similar process. The viscosity grade of the material is determined by the degree of substitution and the molecular weight of the finished product. 

Carboxymethylcellulose Calcium (Calcium CMC) A calcium salt of polycar-boxymethyl ether of cellulose, calcium CMC is obtained by carboxymethylation of cellulose and conversion into calcium salt. Different molecular grades are prepared by changing the degree of carboxymethylation. It is available as a line powder, white to yellowish white in color, and hygroscopic in nature. Calcium CMC has swelling and viscosity-enhancing properties in water. It can swell twice its volume in water [25]. 

The carboxymethylation of cellulose with sodium chloroacetate in an aqueous system generally showed that the 2-OH group was more reactive than the 6-OH group, whereas the 3-OH was the least reactive. A low water content medium resulted in a relatively more uniform reactivity than a high water content reaction [202]. Similarly, carboxymethylation in a nonaqueous system (SO2-DEA-DMSO) [79] resulted in a more uniform reaction and a higher reactivity of the 6-OH group as compared to an aqueous reaction. Interestingly, carboxymethylation with sodium iodoacetate substantially enhanced the reactivity of the 3-OH, which was found to be most reactive under this condition. 

As noted earlier [79], the methylation and carboxymethylation of cellulose in SO2-DEA-DMSO solution resulted in a more uniform reactivity among the three hydroxyl groups. 

The methylation or carboxymethylation of cellulose in DMSO-PF solution [215] resulted in preferential substitution at the 2-OH and 3-OH groups. This was attributed to the presence of methylol groups formed mainly at the C6 position during the cellulo.se dissolution process. 

Th. Heinze, T. Liebert, P. Kliifers, and F. Meister, Carboxymethylation of cellulose in unconventional media. Cellulose, 6 (1999) 153-165. 

Ramos LA, Frollini E, Heinze Th (2005) Carboxymethylation of cellulose in the new solvent dimethyl sulphoxide/tetrabutyl ammonium fluoride. Carbohydr Polym 60 259-267 Rana V (2006) Chemical investigation of Dalbergia sissoo Rox. laef polysaccharides. Ph. D. 

Ca +, as well as with the surfactants used. Two of the most commonly used anionic polysaccharides are carboxymethylcellulose and carboxymethylchitin, obtained by carboxymethylation of cellulose and chitin, respectively. 

A company called MS Ltd. desires to obtain a better control over the carboxylation process in future, which takes place in an isothermal BR. In this context, Mr. Y— the pragmatist— turns to the university and requests that a technology student develop a mathematical model for the process and design of a computer program for the simulation of the DS as a function of time in the carboxymethylation of cellulose in a BR. Miss S, a technology student, accepts the challenge. Imagine that you are Miss S ... 

A classical example of such functionalization is the carboxymethylation of cellulose to produce carboxymethylcellulose (CMC), used in a wide variety of applications as a thickener, stabilizer, binder, or other agent. The functional characteristics of such materials can be controlled with some exactness by controlling the degree of functionalization and the molecular weight of the base polymer. Similar classes of materials can be prepared by the hydrolysis of proteins or the use of various reactions well known to the organic chemist. 

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