Alkyl (C12-15) Benzoate
(al' kil ben' zoe ate).
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C20H32O2 304 (average)

Benzoic acid, C12-15 alkyl ester [68411-27-8].
» Alkyl (C12-15) Benzoate consists of esters of a mixture of C12 to C15 primary and branched alcohols and benzoic acid.
Packaging and storage— Preserve in tight, light-resistant containers.
Identification— Its IR absorption spectrum, obtained by spreading a capillary film of it between sodium chloride plates, exhibits maxima at 2800 cm1 (broad); 2950 cm1 (broad); at 1730 cm1 (medium, sharp); at 1270 cm1 (medium, sharp); and at 710 cm1 (medium, sharp).
Specific gravity 841: between 0.915 and 0.935.
Acid value 401: not more than 0.5.
Saponification value 401 Transfer about 2 g of Alkyl (C12-15) Benzoate, accurately weighed, to a 200-mL flask. Proceed as directed for Saponification Value under Fats and Fixed Oils 401, except to use 50.0 mL of 0.5 N alcoholic potassium hydroxide VS instead of 25.0 mL, maintaining reflux for 2 hours instead of 30 minutes, and rinsing the reflux condenser with 25 mL of water after the reflux period: the saponification value is between 169 and 182.
Refractive index 831: between 1.483 and 1.487, determined at 20.
Viscosity 911 Transfer about 500 mL to a tall-form, 600-mL beaker, and adjust the temperature to 25 ± 0.1. Using a suitable rotational viscosimeter with a spindle having a cylinder 5.63 cm in diameter and 2.25 cm high attached to a shaft 0.32 cm in diameter, the distance from the top of the cylinder to the lower tip of the shaft being 2.91 cm, and the immersion depth being 6.11 cm (No. 1 spindle), operate the viscosimeter at 100 rpm for 60 seconds, accurately timed, and record the scale reading. Convert the scale reading to centipoises by multiplying by the constant for the spindle and speed employed. The average of three viscosities obtained is no more than 100 centipoises.
Water, Method I 921: not more than 0.3%.
Residue on ignition 281: not more than 0.5%.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
(EXC2010) Monographs - Excipients
USP35–NF30 Page 1691