[Code of Federal Regulations]
[Title 27, Volume 1]
[Revised as of January 1, 2008]
From the U.S. Government Printing Office via GPO Access
[CITE: 27CFR21.102]

[Page 550]
 
            TITLE 27--ALCOHOL, TOBACCO PRODUCTS AND FIREARMS
 
 CHAPTER I--ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE 
                                TREASURY
 
PART 21_FORMULAS FOR DENATURED ALCOHOL AND RUM--Table of Contents
 
                Subpart E_Specifications for Denaturants
 
Sec.  21.102  Caustic soda, liquid.

    (a) The liquid caustic soda may consist of either 50 percent or 73 
percent by weight sodium hydroxide in aqueous solution. The amount of 
caustic soda used shall be such that each 100 gallons of alcohol will 
contain not less than 8.76 pounds of sodium hyroxide, anhydrous basis.
    (b) Color. A 2 percent solution of the sodium hydroxide in water 
shall be water-white.
    (c) Assay. The sodium hydroxide content of the caustic soda solution 
shall be determined by the following procedure:

    Accurately weigh 2 grams of liquid caustic soda into a 100 ml 
volumetric flask, dissolve, and dilute to the mark with distilled water 
at room temperature. Transfer a 25 ml aliquot of the solution to a 
titration flask, add 10 ml of 1 percent barium chloride solution, 0.2 ml 
of 1 percent phenolphthalein indicator, and 50 ml of distilled water. 
Titrate with 0.25 N hydrochloric acid to the disappearance of the pink 
color. Not less than 25 ml of the hydrochloric acid shall be required to 
neutralize the sample of diluted 50 percent caustic soda, and not less 
than 36.5 ml of the hydrochloric acid shall be required to neutralize 
the sample of diluted 73 percent caustic soda.
    One ml of 0.25 N hydrochloric acid equals 0.01 gram of sodium 
hydroxide (anhydrous).

[T.D. ATF-133, 48 FR 24673, June 2, 1983. Redesignated by T.D. ATF-442, 
66 FR 12854, Mar. 1, 2001]