Determination of moisture and volatile Matter in cocoanut oils

42 THE COTTON OIL PRESS (CHEMISTS' SECTION) mended for the separation and determination of the saturated and usaturated acids is as follows: W e i g h such a quantity of oil as contains about 2 g. of saturated acids, iu no case using more than a 2o g. sample, into a o_oo cc. Erlenmeyer flask, add 3o cc. of 95% alcohol and a -~ excess of a I-I aqueous solution of potassium hydroxide. Heat on the steam bath until saponification is complete (about one-half h o u r ) . Add a slight excess of dilute acetic acid, using phenolphthalein as an indicator, and bring back to a faint pink color with a dilute potassium hydroxide solution. Measure a quantity of -~ lead acetate solution (6o cc. if a to g. sample is used, L~ CC. for a 2O g. sample) into ~t liter Erlenmeyer flask, add the same amount of water, heat to boiling and wash the neutralized soap solution carefully into. the boiling lead acetate solution. Continue the boiling for about five minutes, shake thoroughly and cool under the tap, rotating the flask continuously so as to cause the lead soap to adhere to the sidas and bottom of the flask. P o u r off the cold aqueous solution, taking care to lose none of the lead soap. Usually the solution is only slightly cloudy with basic lead accetate and no particles of lead soap are to be seen. W a s h two or three times with cold tap water, drain and remove the last drops of w a t e r by meaus of a thin roll of filter paper o r a wad of cotton held by the foi-ceps, or by shaking the end of a clean towel in t h e flask. Do not expose the lead salts to the air any longer than necessary as they slowly absorb oxygen. A d d a quantity of ether (Ioo cc. if a I o g . sample is used, o_oa ce. for a 20 g. saniple) to the flask, shake and w a r m cautiously until the lead soap is entirely loosened from the flask and completely disintegrated. Rinse down the sides of the flask with a small quantity of ether, cork loosely and place hi the ice box over night. Place a 7 cm. ordinary filter paper in a 7.5 cm. diameter Btichner funnel; then fit in a 9 cm. hardened paper as snugly as possible, fitting in wet and drying with alcohol and ether. Decant the lead soap m i x t u r e through this filter, using just enough suction to draw the liquid through. Too much suction causes the moisture in the mixture to freeze and clog the filter, owing to the lowering of the temperature caused by the rapid evaporation' of the ether. T r a n s f e r as much as possible of the precipitate to the filter, rinse out the flask and wash the precipitate four or five times with ether, using a small h o r n spoon to stir it. Care should be taken that the lead soap remain slightly moist; otherwise it is difficult to remove it from the filter paper. Remove the filter paper with the a d h e r i n g precipitate. Separat eas much as possible of the lead soap with a spatula and t r a n s f e r it to a 5oo cc. separatory funnel. W a s h the adhering lead soap into the separator with a stream of ether, then drop the filter into the flask. 9 Shake the contents of the separator, until the lumps of lead soap are disintegrated. T h e n add about 2o cc. of concentrated hydrochloric acid and shake until the soap is decomposed. Add a few co. of hydrochloric acid and water to the flask ill o r d e r to decompose the soap that continues to adhere to the flask and filter paper; then wash into the separator with alternate portions of ether and water until no more particles of lead chloride or soap remain. Again shake the contents of the separator and after settling draw off the aqueous layer, being careful not to lose any particles of undecomposed lead soap. If the soap is not all decomposed shake again with acid. W a s h the ether solution with successive portions of distillcd water until the washings are neutral to methyl orange. Dehydrate the ether sohttion with 6 o r 7 grams of anhydrous sodium sulphate. Then pour as much as possible of the solution f r o m the neck of the separator into a weighed 3oo cc. Erlemneyer flask and run the remaintier from the stem through a smaU filter into the flask. W a s h thc separator and sodium sulphate with several portions of ether and run t h r o u g h the small filter into the flask. Distill off the ether, heat in an oven at about I Io ~ until the weight is constant and weigh the saturated acid fraction thus obtained. T r a n s f e r the ether solution of the soluoble lead soap to a 50o cc. separator, shake with 20 cc. concentrated hydrochloric acid until thc lead soap is decomposed, add 75 cc. of water and again shake. After settling r u n aqueous layer into a beaker. Often drops of the ether solution are trapped in the lea(] chloride precipitate and run off with the aqueous layer. If drops of fatty acid float on the surface of the solution in the beaker, add a few cc. of ether and pour back into the separator, being careful to retain the bulk of the lead chloride precipitate in the beaker. W a s h the ether solution with successive portions of distilled water until the washings are neutral to methyl orange. Dehydrate with anhydrous sodium sulphate and transfer to a 30o cc. weighed Erleumeyer flask according to the directions for the saturated acid determination. Distill off most of the ether and remove the remainder by heating in an oven at II5~ ~ C. for at least an hour while passing a stream of carbon dioxide through the flask. Cool in an atmosphere of carbon dioxide. T h e n remove the carbon dioxide from the flask by placing it under a bell j a r connected with a VAcuum system and exhausting tile j a r a n u m b e r of times. W e i g h the unsaturated acid fraction thus obtained. Determine the iodine nunabers of both saturated acid and unsaturated acid fractions. Tile iodine number of the saturated acid fraction usually is between 5 and xo, but it is sometimes as high as 25. The correction for the unsaturated acids that contaminate the saturated acid fraction is calculated as follows : :Iodine No. of Sat. Acids X~oo~A (percentage of unsaturated Iodine No. of Unsat. Acids acids contaminating the saturated acid fraction). T h e proper correction is then obtained by means of the formula A • in which B is the percentage of ioo impure saturated acids. This correction is subtracted from the percentage of impure s a t u r a t e d acids and added to the percentage of unsaturated acids actually determined. R. D. O I L A R G O E S T O S O U T H A M E R I C A R. D. Oilar sailed in April for South America to build, iustalI and put into operation ( l a r d ) compound, winter oil, butteriue, oleo oil aud stearine, and refrigerating plants. H e expects to correct the present practice of the local slaughterers who now produce no edible fats except hog lard sending practically all the fats to the inedible tanlr for soaps, much of which should be made into edible products. A f t e r completing the work in Peru, he expects to continue on to Chili, Argentine, Brazil and Venezuela. H e would be pleased to g (...truncated)