Document 6B0VKvOM1edkJ6L4ZBmMryo96

Hfonsanto Chemical Company Anniston liethod No. 14-42-48 SUBJECT: Acid Humber of Liquid Aroclors L?_:THOD: Titration with Alkali using IPhenol Red Scope The Acid Number is the weight in milligrams of sodium hydroxide re quired to neutralize one gram of Aroclor to pH 7.6. It thus includes any hydrochloric acid, ferric chloride, and other inorganic or organic constituents having acid characteristics. It corresponds to the Neu tralization Number of ASTI,I Designation D188 except that the latter is expressed in terms of KOH instead of NaOH and has a somevjhat higher (phenolphthalein) end point. . Procedure . To 100 ml. of adjusted (pH 7.6) solvent containing indicator slowly add 0.1 H NaOH dropwise until the color corresponds approximately to pH 7.6 when compared against a suitable reference solution. Readjust if necessary to maintain pH 7.6. Add 50 grams (tig.) of liquid Aroclor and mix well. Titrate from micro buret with 0.01 N NaOH until the original red color of the solvent is restored. A portion of solvent in a similar container is a useful reference in determining the end point. The match is governed by estimation of the intensity of red because the hue is not exactly reproduced on account of the yellow color introduced by the Aroclor. 1 ml. of 0.01 N NaOH * 0.4 llgm. NaGE. Calculate in terms of lifja. NaOH per gm, of sample."" Report to 4 decimal places. JS.sPA-3?JfajlL.0g tigm. NaOH/gm. . g. of sample , . Example: If titration is 0.08 ml. for 50 g. of Aroclor, the Acid Humber is 0.08 X 0.4/50 0.00064 fclgra. NaOH/gm. Reoort as 0.0006, Solutions Required . Solvent: riix 600 ml. of benzol, 200 mi; of 3-A alcohol and 200 ml. of acetone. Add 5 ml. of 0.2>i phenol red solution. Phenol Red Solution, 0.2$: To 0.1 gm. of dry indicator in a small beaker add exactly 2.0 ml. of 0.1409 JN NaOH. Stir to dissolve and dilute with 3-A alcohol to 50 ml. Reference Buffer pH 7.6: Dissolve 0.41 g. Nan3P04 and 0.59 gm. Na2HF04 (both anhydrous) in 100 ml. of '.rater. Add 0.5 ml. of 0.2,. phenol red. Solution is used for reference in adjusting the solvent if LaNotte pH 7.6 color standard is not available. DSW 330880 STLCOPCB4077524 Acid Number of Liquid Aroelars -2 - Standard 0.01 N^NaOH: 5 ml. of .5 N NaOH to 250 ml. vol. of 3~A al cohol. Protect at all times from atmospheric C02. ' Note ' By using 250 ml. acetone in solvent instead of 200 ml. a 100 gm sample of 1254 may be taken for analysis. FABicm ' 1-30-45 . Copied by rs 4/23/48 DS\N 330881 STLCOPCB4077525