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P-C-111C <br /> 4.5.3 More volatile aromatics. Place 100 ml . of the compound into a tall i <br /> form gas washing bottle of approximately 250-m1 . capacity equipped with a <br /> fritted glass dispersion disk on the stopper. Attach the outlet to a washing <br /> bottle containing concentrated sulfuric acid to dry the air before it enters <br /> a gas washing bottle, approximately 250 ml . capacity, containing 100 ml . of <br /> reagent. The reagent is made by adding 95 ml . concentrated sulfuric acid to 5 <br /> ml . of 40 percent formaldehyde solution. The use of a bottle here without <br /> fritted glass facilitates the washing of the tube after use. Draw air through <br /> the system for 5 minutes at the rate of approximately 180 ml . per minute, <br /> using suction. Observe the inside of the tube for discoloration (the solution <br /> discolors in the presence of more volatile aromatics) . The addition of a <br /> silicone type antifoaming agent, free of benzene, to the compound prior to , <br /> passing air through the system is recommended. For a blank, use 100 ml . of �! <br /> the comparison formula of 4.5. 19.2. A definite brown discoloration of the <br /> tube shall be taken as evidence of benzene, toluene, or other undesired hydro- <br /> carbons, and the compound displaying such color reaction shall be judged as <br /> having failed the test. Coloration not essentially different from that obtained <br /> with the comparison formula shall be disregarded. The type of coloration un- <br /> desired may be determined by using a solution of 0.5 ml . toluene dissolved in <br /> 100 ml . of the comparison formula of 4.5. 19.2. <br /> 4.5.4 Water content. Use a 250 ml . round bottom, short neck flask with <br /> one plain side inlet tube, a 10 ml . Barrett distillingreceiver and 20 <br /> a 0 <br /> i <br /> millimeter (mm.) condenser. All connections shall be by ground glass joints. <br /> Transfer 100 ml . of the compound to the flask, add a boiling stone and 25 ml . ^! <br /> water-free normal butanol . Insert a thermometer, range 20° to 580°F. , 76 mm. •,7 <br /> immersion, through the side tube until the bulb is approximately 1/4 inch above <br /> the surface of the liquid. Apply heat and distill slowly. Drain the lower <br /> layer in the receiver into a 100 ml . glass stoppered graduated cylinder. When <br /> the distillate becomes clear, increase the heat and continue the distillation <br /> until the temperature of the vapors reach 300°F. During this period, the <br /> distillate shall be drained into the graduate. Two graduates shall be used, <br /> dividing the layers between them. When cool , record the total volume of <br /> distillate (TV) . Add anhydrous potassium carbonate until the solution is <br /> saturated and a slight excess settles out. Record the combined volumes of the <br /> top layers (TL) after salting out. <br /> i <br /> Percent water in compound = TV - TL _ <br /> 10 <br /> : <br />