Nomenclature
CAS number: 9004-32-4
Carboxymethyl ether cellulose sodium salt; sodium carboxymethylcellulose; sodium cellulose glycolate; Cethylose (Ascher); CMC (Stuart); Cel-O-Brandt; Glykocellon; Carbose D; Xylo-Mucine; Tylose MGA; Cellolax; Polycell.
RnOCH2COONa.
Description and references
Prepd by treating alkali cellulose with sodium
chloroacetate: Faith, Keyes & Clark's
Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds.
(Wiley-Interscience, New York, 4th ed., 1975) pp 235-238. Review
and bibliography: Ott, Cellulose and Cellulose Derivatives, New York, 1946 (2nd ed., 1955).
Properties
White granules. Soly in water depends on degree
of substitution. Water-soluble CMC is available in various viscosities
(5-2000 cP in 1% soln), and the soly is equally good in hot and cold
water (difference from methyl cellulose). Also the presence of metal
salts has little effect on the viscosity. Solns are stable between
pH 2 and 10. Below pH 2 precipitation of a solid occurs, above pH
10 the viscosity decreases rapidly. pKa 4.30. The free acid is obtained from aq
soln at pH 2.5 and may be precipitated with alcohol.Use
In drilling muds, in detergents as a soil-suspending
agent, in resin emulsion paints, adhesives, printing inks, textile
sizes, as protective colloid in general. As stabilizer in foods.
Pharmaceutic aid (suspending agent; tablet excipient; viscosity-increasing
agent).