Sorbitan Monostearate
[Graphic formula same as for Sorbitan Monolaurate, except that R is (C17H35)COO.] Sorbitan, esters, monooctadecanoate. Sorbitan monostearate [1338-41-6]. » Sorbitan Monostearate is a partial ester of Stearic Acid with Sorbitol and its mono- and dianhydrides. It yields, upon saponification, not less than 68.0 percent and not more than 76.0 percent of fatty acids, and not less than 27.0 percent and not more than 34.0 percent of polyols (w/w).
Packaging and storage
Preserve in well-closed containers.
Identification
A:
The residue of stearic acid obtained in the Assay for fatty acids has an acid value (see Fats 401) between 200 and 215, about 1 g of the residue, accurately weighed, being used, and an iodine value (see Fats and Fixed Oils 401) of not more than 4.
Acid value 401:
not more than 10.
Hydroxyl value 401:
between 235 and 260.
Saponification value 401:
between 147 and 157.
Water, Method I 921:
not more than 1.5%.
Residue on ignition 281:
not more than 0.5%.
Heavy metals, Method II 231:
not more than 0.001%.
Assay for fatty acids
Transfer about 10 g of Sorbitan Monostearate, accurately weighed, to a 500-mL conical flask, cautiously add 100 mL of alcohol and 3.0 g of potassium hydroxide, and mix. Proceed as directed in the Assay for fatty acids under Sorbitan Monooleate, beginning with Connect a suitable condenser.
Assay for polyols
Proceed with Sorbitan Monostearate as directed for Assay for polyols under Sorbitan Monooleate.
Auxiliary Information
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Chromatographic Column
USP32NF27 Page 1350
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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