ISOPROPYL CITRATE MIXTUREPrepared a

ISOPROPYL CITRATE MIXTURE
Prepared at the 17th JECFA (1973), published in FNP 4 (1978) and in FNP
52 (1992). Metals and arsenic specifications revised at the 61st JECFA
(2003). An ADI of 0-14 mg/kg bw was established at the 17th JECFA
(1973)
SYNONYMS INS No. 384
DEFINITION
Chemical names Citric acid mixed ester of 2-propanol. The article of commerce,
monoisopropyl citrate mixture, is composed of approximately 38 parts by
weight of isopropyl citrate in 62 pars by weight of mono- and diglycerides
Structural formula
where R is either hydrogen or a isopropyl group. The major component of
the 38 parts of isopropyl citrate mixture is monoisopropyl citrate
(approximately 25 parts), the remainder being diisopropyl citrate
(approximately 9 parts) and triisopropyl citrate (approximately 4 parts)
Approximate composition:
Monoisopropyl citrate - 27 parts by weight
Diisopropyl citrate - 9 parts by weight
Triisopropyl citrate - 2 parts by weight
DESCRIPTION Oil miscible semi-solid material. The commercial product, monoisopropyl
citrate mixture, is a viscous, colourless syrup exhibiting some crystallization
upon standing, and may be further specified as to saponification value,
acid value, citric acid and isopropyl content.
FUNCTIONAL USES Antioxidant, sequestrant
CHARACTERISTICS
IDENTIFICATION
Solubility (Vol. 4) Soluble in water and ethanol
Test for citrate Reflux 3 g of sample with 50 ml of sodium hydroxide TS for 1 h, and let
stand to cool. This solution is used for the following tests:
(1) Neutralize the solution with a (1 in 20) sulfuric acid solution, add an
excess of mercuric sulfate TS, heat to boil, and add potassium
permanganate TS. The permanganate colour of the solution disappears,
and a white precipitate forms.
(2) Neutralize the solution with hydrochloric acid, add an excess of calcium
chloride TS, and boil. A white crystalline precipitate is formed which is
insoluble in sodium hydroxide TS, but soluble in dilute hydrochloric acid
TS.
Test for isopropanol Reflux 2 g of sample with 50 ml of sodium hydroxide TS for 1 h. Distil off 20
ml. Place 8 g of chromic oxide in a flask, add 15 ml water and 2 ml
concentrated sulfuric acid. Provide the flask with a reflux condenser and
add 5 ml distillate slowly through the condenser. Reflux for 30 min, then
cool and distil off 2 ml. Add 3 ml water and 10 ml mercuric sulfate TS to the
distillate. Heat in a boiling water bath for 3 min. A white or yellow
precipitate within 3 min indicates the presence of isopropanol.
PURITY
Acids other than citric acid Should be absent
Alcohols other than
isopropanol
Should be absent
Sulfated ash (Vol. 4) Not more than 0.3%
Lead (Vol. 4) Not more than 2 mg/kg
Determine using an atomic absorption technique appropriate to the
specified level. The selection of sample size and method of sample
preparation may be based on the principles of the method described in
Volume 4, “Instrumental Methods.”