INDUSTRIAL A N D ENGINEERING CHEMIXTRY
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CONCLUSION Vitovim bread when fed as the sole food produces normal growth and health in young test animals. Already eight generations of mice and five generations of albino rats have been reared on this bread and water. When animals are allowed free choice between breads of various kinds-white, whole-wheat, and Vitovim-natural instinct guides them to the more nourishing Vitovim loaf. I n a 6 weeks' test it was found that animals selected Vitovim for 59 per cent of their diet, whole-wheat bread for 27 per cent, and ordinary white bread for only 14 per cent. This is already being duplicated in the ca'se of children, where the child is naturally selecting more of Vitovim bread in preference to other bread. The Vitovim bread is being fed to children in private homes and in institutions under competent direction. Observations are also being made with the ordinary bread.
Vol. 15, No. 12
Both groups are given the same diet with the exception of the bread. The results confirm the conclusions derived from the animal feeding experiments. The groups receiving Vitovim bread as a part of their diet are makingluniformly greater gains in height and weight than children of the same age and under the same conditions of the experiment but whose diet contains the ordinary bread. ACKNOWLEDGMENT This work was authorized and carried out under the synipathetic backing of George S. Ward, president of the Ward Baking Company. Due credit is here given to all the men in the laboratory, and to R. M. Allen, director of the Research Products Department, for the helpful suggestions and cooperation they have given toward the completion of this work.
A Rapid Method for the Analysis of Soap Powder' By Fred F. Flanders and Anna D. Truitt CHBMICAL LABORATORY, MASSACHUSETTS DEPARTWENT OR MENTALDISEASES, BOSTON, MASS.
HE routine examination of a large number of samples of soap powder by means of the separation of soap from alkaline salts, based on the solubility of soap in 95 per cent alcohol12 has shown the method to be unsatisfactory in several respects. It is very slow and tedious because of the repeated dryings and weighings necessary, and, as pointed out by Lowl3is subject to defects inherent in the supposition that all the soap dissolves in the alcohol while the alkaline salts remain in the insoluble portion. The writers have corroborated Low's findings that even with absolute alcohol some sodium carbonate dissolves. They have also demonstrated that the residue will often contain much more than traces of soap. By applying corrections for these factors when dealing with soap powders made up of soap and sodium carbonate, very good results are obtainable, but a t the additional expense of much time and labor. The writers have worked out a method by means of which weighings are avoided entirely, the whole operation being conducted by titration on the same 2-gram sample. It appears to be quite as accurate as the old method, and is much more rapid, requiring little more than an hour for a complete analysis. The method is based on the titration of total alkali, with subsequent extraction and titration of the fatty acids in chloroform solution. The separation of soap and sodium carbonate is thus accomplished in a chemical instead of in a physical way.
PROCEDURE Weigh accurately 2 grams of sample and transfer to a 4CO-cc. beaker. Add 100 cc. of hot water and heat to obtain a clear solution. Titrate while hot with 0.5 N hydrochloric acid, using methyl red as indicator. After the end point is reached, add 2 cc. excess of 0.5 N hydrochloric acid, several pebbles to prevent superheating, cover with a watch glass, heat to boiling, and boil gently 10 minutes to remove carbon dioxide. Titrate back to end point with 0.1 N sodium hydroxide. Add 2 cc. excess,of 0.5 N hydrochloric acid, cool, and transfer to a separatory funnel. Extract with three portions of chloroform, using 25 cc. for each extraction, first rinsing the beaker with each portion. Draw off chloroform through 1 Received 2
8
May 28, 1923.
Bzrr. Standards, Circ. 62, 2nd ed., p. 31. THISJOURNAL, 11, 116s (1919).
a dry filter into a dry Erlenmeyer flask. Wash filter with 25 cc. chloroform to remove traces of fatty acids. Heat t o boiling and boil gently 5 minutes to remove carbon dioxide (pebbles should be added before heating to prevent superheating). Titrate the fatty acids while still hot with 0.1 N sodium ethylate, using 5 drops of phenolphthalein indicator made up in absolute alcohol (1 gram = 100 cc.). The titration should be conducted quite rapidly and carried to the first permanent red color. CALCULATION
(Cc. 0.5 N HCI)
- (cc. 0.1 N NaOH) - (cc. 0.1 N CZHsONa) X 0.0053 2
(Cc. 0.1 N C2HsONa) X 0.0306
= NaCOs
~
anhydrous soap
2
PREPARATION OF REAGENTS The sodium ethylate is prepared by dissolving 2.3 grams of cleaned metallic sodium in 1 liter of absolute alcohol.4 It is standardized against ordinary 0.1 N hydrochloric acid, using phenolphthalein as indicator. As absolute alcohol has a rather large coefficient of expansion, it should be restandardized a t the temperature at which it is used when that varies more than a degree from the temperature a t which standardization last took place. If a precipitate appears in the ethylate it should be filtered. The chloroform should be tested for acidity by adding indicator to 100 cc. and titrating with ethylate; if more than a single drop is required to give a strong end point, the chloroform must be washed in a separatory funnel with dilute sodium hydroxide. After the layers have separated well it should be filtered through a dry filter. Dry flasks must be used in the chloroform titration, as a single drop of water will entirely vitiate the results. The factor selected, 0.0306, is the mean 6etween the molecular weights of sodium oleate and sodium stearate. By making a moisture determination the results may be checked against 100 per cent. Owing to the presence of small amounts of sodium chloride and sodium sulfate, and sometimes unsaponified fat, in soap powders made up of soap and soda ash, the results will generally add up to 98 or 99 per pent. 4
Folin and Flanders, J . A m . Chem. SOC.,34,774 (1912).
