Packaging and storage
Preserve in well-closed containers.
Weigh accurately 3 g into a 250-mL flask attached to a reflux condenser, add 50 mL of a mixture of isopropyl alcohol and toluene (5:4), and boil gently until the wax is completely dissolved. Remove the flask from the condenser, add about 1 mL of phenolphthalein TS
, and immediately titrate with 0.5 N alcoholic potassium hydroxide VS to a faint, reddish yellow color. [NOTE
Do not allow solution to cool; titrate at warm temperature after refluxing.]
Calculate the acid value as the number of mg of potassium hydroxide required to neutralize the free acids in 1 g of Carnauba Wax. The acid value so obtained is between 2 and 7.
Saponification value 401
To the solution from the test for Acid value
add 15.0 mL of 0.5 N alcoholic potassium hydroxide VS, reflux for 3 hours, and titrate the excess alkali with 0.5 N hydrochloric acid VS to a yellow-amber color. Perform a blank determination (see Residual Titrations
under Titrimetry 541
). The saponification value is the summation of the ester value so obtained and the Acid value
, and it is between 78 and 95.
Residue on ignition 281
Heat 2 g in an open porcelain or platinum dish over a flame: it volatilizes without emitting an acrid odor. Ignite: the weight of the residue does not exceed 5 mg. Not more than 0.25% is found.