NOTES.
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B or C, and as A fills, not only is practically all of the liquor forced from B t o C, b u t considerable quantities of air pass up through C and out. As A empties, the liquor passes back from C to B, and considerable air is drawn from C through B into A . I n this way the air of the generator is continually being partly replaced by fresh air. \\’hen once started, the generator requires no further attention,
number of THISJOURNAL,as well as to several inquiries from other readers, the writer wishes to state t h a t in his article, in the January number, on “Turpentine and I t s Adulterants,” the terms “very light naphtha” and “exceedingly light petroleum products” were h’OT intended to include ordinary gasoline, but merely such unusual products as “hexane” petroleum ether, etc.
and acetification is usually complete in a few weeks, working at room temperature. The shavings have a clarifying effect on the liquor so t h a t when the finished vinegar is withdrawn i t is brilliant. The generator is filled and emptied through the T tube between bottles B and C. When not in use these bottles should be kept full of vinegar. I t is evident t h a t the device can be operated on a smaller or larger scale than the one shown. The present size will produce about three gallons of vinegar a t one charge. H. C. GORE.
Inasmuch a s the writer’s statement t h a t his method gives low results with such products, if understood according t o Mr. Acott’s interpretation, and coupled with his statement a s t o the use of gasoline for adulteration, would greatly reduce the general applicability and utility of the method, the writer desires to say t h a t he too, has frequently found samples of turpentine adulterated with petroleum products resembling gasoline, and t h a t the method described, gives excellent results (go per cent. on known mixtures) in such cases. The writer has also received a number of inquiries concerning the conditions of observation of the butyro-refractometer readings,
NOTE ON TURPENTINE. Replying t o Mr. R. H. Acott’s statement in the February
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 .
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The reasons for employing these readings rather than any other physical constant, were ease of application and smallness of amount required, the time consumed being b u t a few moments, and a drop or two of material being amply sufficient for the determination. The readings given i n connection with the fractionation results are supplied merely t o show the impracticability of arriving a t quantitative results by t h a t method. Some other physical constant might have been used, and undoubtedly have answered equally as well. The readings given i n connection with the writer’s method I would emphasize t h a t these are by no means aa -and essential part o i the method-are interesting merely as they demonstrate the possibility of recognizing, very quickly, approximately, the kind of petroleum products used, low readings indicating light products, high readings, heavier ones. The writer took the readings a t z j o C., and used ordinary white light, those being the most convenient conditions ; and these having been used throughout, the figures given, are comparable with each other. It is assumed t h a t each operator, before using this or a n y other similar new method, will try i t on known substances, and will use his own standards and constants, as a basis for comparisons and conARTHURE. PAUL. clusions. LABORATORYOF MARINER A N D HOSKINS. CHICAGO,ILL.,Feb. 13. 1909.
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DETERMINATION OF ACETANILID IN HYDROGEN PEROXIDE SOLUTIONS. Recently I had occasion t o determine the proportion of acetanilid i n a commercial sample of hydrogen peroxide. Our client stated t h a t one chemist whom he had consulted on the subject, declared i t to be impossible, and i t must be admitted, t h a t so far as the literature is concerned, there seems to be nothing t o fit t h a t particular case. It is a matter of record t h a t boiling acetanilid with strong hydrochloric acid or with strong caustic alkali, causes a dissociation, with formation of anilin. The reaction is quantitative. The method of Seidell’ depends on this conversion by acid. A five minute vigorous boiling in a solution containing about one-fourth of concentrated hydrochloric acid was found b y him sufficient to effect the change. T h a t observation I have been able to confirm. I n the solution after cooling i t was found possible t o determine the anilin by titration with Koppeschaar’s solution-practically the solutim used i n urea determinations diluted t o a convenient strength. The end reaction is when all of the anilin has been precipitated a s the bromine substitution product, when the excess of bromine imparts a yellow tinge to the solution. For standardizing or for determining acetanilid in many pharmaceutical preparations, his process serves very well, b u t i n the presence of the peroxide, the preliminary boiling completely destroys the acetanilid, affording a yellowish solution i n which bromine gives no precipitate. It was found t h a t the desired result could be obtained by boiling with strong caustic alkali i n presence of granulated zinc, and distilling over the anilin formed, by the aid of a current of steam. After some experimenting, t h e following plan was worked out: I n a side-neck flask of 200 cc. capacity, place about half a stick of caustic potash or soda (6-7 grams). 1
J. Am. Chem.
S o c . , 29, 1091.
Apr., 1 9 9
Add about 20 cc. of water to dissolve, and then 25-30 grams of granulated metallic zinc (the zinc had best be in a s fine particles as can be obtained i n “granulated” form. There is reason, however, to believe that “zinc dust” is too finely divided for this purpose). Then add a measured amount (not over 50 cc.) of the solution to be tested. Connect the flask on the one side with a flask to supply steam, arranging the tube to deliver steam near the bottom of the solution; connect on the other side with a condenser. The condenser should deliver into a Peligot bulb tube or some other arrangement by which the distillate is immediately brought i n contact with moderately strong hydrochloric acid. Raise the heat on the flask slowly, and when nearly hali‘ of the contents have distilled over, start the steam to passing through. The end of the distillation is a matter of guess. When the anilin is coming over i n quantity, fumes are t o be seen i n the receiver, b u t for the last portions they cannot be seen. \\’hen i t is judged t h a t all has come over, detach the receiver and catch what comes over later in a fresh receiver or a beaker, and titrate i t separately. To prepare the volumetric bromine solution, dissolve 2 5 grams of caustic potash in 20-40 cc. of water, cool, and add liquid bromine until i t appears supersaturated. Then dilute to about zoo cc. and boil out excess of bromine (judged by the color). Cool, and dilute to one liter. This should give a solution of which I cc. = nearly 0.01 gram acetanilid. Standardize b y means of a solution containing 0.5 gram acetanilid in zoo cc. of water, using 30-50 cc. lots at a time, treated either by distillation on the manner above given, or by boiling with strong hydrochloric acid. Either method was found to give the same result with the same amount of acetanilid, The method was tested by first distilling known quantities of the sample and titrating the distillate, then adding known amounts of acetanilid t o the same quantities of the sample, and distilling. The distillates took just the additional amount required by the acetanilid added. The presence of acetanilid was indicated by obtaining the iso-nitril reaction on the original sample. ELWYN \TALLER.
NOTE ON MR. BAILEY’S PAPER ON ACCURACY IN SAMPLING COAL.‘ I n the carefully planned and admirably carried out series of experiments described i n his paper Mr. Bailey has shown t h a t the errors due to sampling are likely to be much larger than most of us have realized. While the paper deals specifically with coal, the conclusions are applicable t o the sampling of all mixtures of solids. It is the first attempt that has been made to measure quantitatively t h e errors due t o too small a n initial sample and t o insufficient crushing before quartering. No one realizes more fully than Mr. Bailey that there are other parts of sampling than those he has investigated, i n which serious errors may occur. The U. S. Steel Corporation have studied some of these and formulated rules for taking samples of their principal raw materials. This society and others have done much to insure the introduction of more accurate methods of analysis, b u t no one has done anything t o insure that the samples represented the material correctly. To insist on the use of methods that THIS JOURNAL,March, 1909.
