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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
be inevitable, if the simple course of procedure were followed, was to evaporate to dryness in the presence of filter paper or asbestos to absorb the substances to be extracted and then to carry out the extraction with the solvent desired in a Soxhlet extractor. After saponifying lard and neatsfoot oils which were compounded with mineral oils, i t was found that i t expedited matters to absorb the whole mass in asbestos, drive off all water and extract with ether. This ' is a fairly good way to proceed but the author has recently found a simpler and quicker way. These points are mentioned to convey an idea of the trouble involved in making a separation of some mixtures of Saponifiable and unsaponifiable oils. Animal oils are much more troublesome than vegetable oils. Mixtures of lard or neatsfoot oil and mineral oil, sperm oil and hide grease are examples of troublesome mixtures with which to work. The method that has been followed in this laboratory for some time for mixtures of this kind depends upon the presence of relatively large amounts of alcohol which holds both the neutral and the saponifiable oil in solution or suspension. I t has been found to give uniformly good results and is as follows: I . Method Used when Non-saponifiable I s To Be Determined. Saponify in a flask in the usual way with alcoholic potash or sodium or potassium alcoholate, and when the saponification is complete evaporate about half the alcohol unless the soap formed separates on cooling i n which case more alcohol should be added until i t dissolves. If a short glass tube is used as air condenser by the time the contents of the flask have boiled sufficiently about half the alcohol will have gone off. Add rather more than an equal volume of ether, and transfer, by washing the contents of the flask with ether into a separatory funnel. Now add water while slowly rotating the flask until after a separation of the layers no further turbidity occurs in the lower layer on adding more water. About 5 or 6 volumes of water are added in this way, Draw off the lower layer to another funnel and add more water and shake out with more ether and separate, when both layers are clear. This extract may contain a little nonsaponifiable oil and is added to the main body of the ether solution of non-saponifiable oil after the first ether layer containing the bulk of the non-saponifiable oil has been washed two or three times with water to remove alcohol t h a t was dissolved in the ether. After washing free of soap and alcohol, this ether extract with the second ether extract is evaporated in a tared flask and weighed. b:e have carried out this procedure for several months on the classes of oils mentioned above and have never had one troublesome emulsion. I n most all cases there was practically no waiting necessary, as the layers separated perfectly in a few minutes. It does not matter how much free alkali is present. There would obviously be some difference in the amount of dilution of the alcohol necessary with different non-saponifiable substances, such as higher alcohols or mineral oils. I n the case of mineral oil as the non-saponifiable matter, the author had very little doubt on the subject, as i t is only slightly soluble in strong alcohol and when the alcohol is diluted to 20 per cent. strength i t apparently holds a very minute amount, as the second shaking out with ether removes i t all. I n the case of an oil that i t was thought might contain some saponifiable matter, but was all mineral oil, 99.5 per cent. was recovered after treating by this process.
July, 1909
I n the case of higher alcohols the method seems to give as reliable results as with mineral oil although the slight solubility of the alkaline soaps from waxes may make i t necessary to follow Method IX before referred to. 2. Application 01 the .Vethod when Determining Free Acid in Oils. I n the determination of free acid in oils where the molecular weight is not known, i t is not sufficiently accurate to titrate with caustic potash solution and calculate it, say, to oleic acid. I n such instances i t is necessary to neutralize and remove the free acid and to weigh up the residual neutral oil. This has been a difficult thing to accomplish however, due to emulsions in many instances. If the method given above, with slight modifications, is used there is no trouble on this score. Dissolve the oil in ether and add an equal volume of alcohol and a few drops of phenolphthalein solution. Then add approximately normal caustic potash solution until very slightly alkaline, put in a separatory funnel rinsing the weighed beaker with about a s much ether as was used in the first instance and then add water slowly until all the oil seems to be separated from the lower layer. Rotate carefully to wash most of the alcohol out of the ethereal layer and allow to settle until clear. Draw off the lower layer into a second separatory funnel, wash the ethereal layers with water and the aqueous layer with ether after adding more water. Unite the two ether layers and wash with a little more water. Evaporate the ether in a tared flask. This residue is the neutral oil and the difference between the two weights is the free acid. With the application of this method to cases I and 11, other solvents such as chloroform or benzol may be employed, but ether gives much better separations. 3. Breaking Emulsions. I n general, if it is necessary to extract a n ethereal solution with aqueous alkali, proceed either according to the method just described of determining free acid in oils or as follows: If an emulsion has formed, add alcohol until a clear solution or clear layers result, then twice a s much (or more) ether as alcohol is added and then slowly add water and rotate the flask or separatory funnel until no more oil separates from the aqueous layer. Sometimes this may take several hundred cubic centimeters of ether and may seem wasteful, but when the time saved is considered and the fact that the ether in both layers is recoverable that objection is S. S. SADTLER. removed. LABORATORY O F SAMUEL P. SADTLER & S O N , PHILADELPHIA, PA.
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AN ELECTRICALLY HEATED INCUBATOR. A recent improvement in laboratory apparatus, for which there was a real demand, is the electrically heated bacteriological incubator. I n all probability it will, within the near future, replace the old style gas-heated incubator, and for this reason a brief description will be of interest to all who have occasion to use such a n apparatus. The difficulty of maintaining a constant temperature and the liability of fire in the gas-heated incubators are well known to those who have used them. Consequently, a simple arrangement which will overcome these will be welcomed. The apparatus consists of a three-walled oven made of copper, providing a water jacket and a n air space. The
BOOK REVIEWS A N D NOTICES. latter continues down into the base, vvhich contains two or more ordinary incandescent lamps, depending upon the size of the incubator. A mercury thermo-regulator is inserted i n the water jacket, the bulb of which contains about two pounds of mercury and has a capillary glass tube a t tached, through which the expansion and contraction takes place, thus magnifying a n y slight change of temperature.
The current passing through the regulator is automatically closed or opened by the rise or fall of the mercury in the capillary tube, the point of contact being adjusted by turning t h e screw provided for this purpose. The incandescent lamps in the base and the regulator are connected with a make and break device, which constitutes the simple arrangement for maintaining a constant temperature in t h e inner compartment of the incubator and this temperature is noted b y a thermometer, the top of which projects above the top of the apparatus. The oven is entirely surrounded with insulating material a n d is provided with two doors, the outer one being well insulated and the inner one is made of glass, all of the insulating material being finished in white enamel. Tests covering 45 days were made, which showed that the cost of operating was small and t h a t the fluctuation of temperature in the incubator, during this time, was a small fraction of one degree, notwithstanding the temperature of t h e room changed about 18 degrees every 24 hours. T h e incubator is patented and manufactured by Scientific Materials Company, Pittsburg, Pa. CHESTERF . FISHER.
LOSS O F ALCOHOL
FROM LIQUIDS L O W I N ALCOHOL.
T h e attention of the writer was called to this subject by a controversy which occurred between him and a chemist employed by a breuing company as to the percentage of alcohol in a specimen of beer low in alcohol. The results are placed on record; they may be of some interest to other chemists who may have to deal with a similar piece of work Four specimens of the beer in question were analyzed and found t o contain the following percentages of alcohol : 0.94, 0.83, 0.82 a n d 0.74. The beer was contained in the ordinary pint bottles closed with cork-lined tin caps crimped on. I n getting the sample for analysis the caps were loosened just enough to be sprung off; about I I O to 125 cc. were withdrawn a n d t h e caps snapped back i n place. The bottles were returned to t h e source from whence they came and were, after a n interval of about thirty days, sent to a representative of the brewing company which had sold them. The alcohol was then redetermined by the other chemist who reported the percentages of alcohol i n the same order a s found in the original analysis b u t so much below the first figures t h a t none of them exceeded 0.50 per cent. alcohol. It appeared t o the writer to be a matter of some interest to know whether the beer kept under these conditions was likely t o lose a p a r t of the alcohol as was indicated by these figures. Accordingly a bottle of the same brand of beer was analyzed March 15th and found to contain 0.96 per cent. alcohol. It was handled exactly a s the other samples had been except t h a t i t was kept i n the writer's office. On April 23rd the alcohol was redetermined, when i t showed exactly the same percentage as before, 0.96. I n spite, therefore, of the interval of thirty-nine days, no loss of alcohol could be detected. The bottle was kept a s before until May 31st, a further period of thirty-eight days. During this time a small quantity of mould appeared i n the liquid, though i t did not smell sour. The mould was filtered o u t and the alcohol redetermined, mhen i t was found t o be 0.85 per cent. This difference is so slight t h a t i t may possibly be due t o experimental error, b u t seems rather t o indicate a very slight loss of alcohol. T h e results here given show, as a n answer to the main question, t h a t a liquid like the one under discussion does not, under the conditions named, lose more than a trace of alcohol in a period of over t w o and one-half months. W I L L I . E. ~ BENTLEY. ATHENS,OHIO.
BUREAU O F STARDARDS ANALYZED SAMPLES. A sample of acid open-hearth steel with 0.6 carbon is now ready for distribution, also a new sample of Bessemer 0.4 carbon in place of t h a t hitherto supplied b u t now exhausted. The next samples to be ready will probably be basic openhearth 0.4 carbon (renewal) and a vanadium steel with about 0.2 per cent. 5'. Certain iron ores are in preparation, b u t the dates of issue cannot be now given. W. F. HILLEBRAND.
BOOK REVIEWS AND NOTICES. Jahrbuch des Vereins der Spiritus-Fabrikanten in Deutschland, des Vereins der Stdrke Interesenter in Deutschland, and Vereins Deutscher Kartoppel-trockner. Xeunter Jahr-
