Mar., 1916 T H E J O U R N A L O F 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 2.57

rinsings to the solution already in the flask. Make the volume up to IOO cc., mix thoroughly and transfer a n aliquot of 25 cc. t o a z j o cc. glass stoppered Erlen- meyer flask. Proceed as in the assay of mercuric chloride tablets, using 15 cc. z N sodium hydroxide solution after first rendering the strongly acid solution alkaline.

I cc. N/IO iodine solution = 0 .01257 g. ammo- niated mercury.

reflux condenser about z grams of the ointment (accurately weighed into a small flask) with 20 cc. nitric acid until all the mercury has dissolved. Pour the acid solution through a plugget of cotton into a IOO cc. graduated flask, and rinse the fat in the flask on the water bath two or three times more, first with a small quantity of diluted nitric acid and then with 2 0 cc. portions of water. To this solution, add a 3 per cent potassium permanganate solution until the former is permanently pink or until brown flakes separate. Decolorize with a 3 per cent solution of ferrous sulfate and finally make the volume up t o IOO cc. To a n aliquot of this solution, add a few drops of ferric alum solution, and add a n excess of N/IO KSCN solution. Titrate the excess with N/IO HgNOP solution, and finally complete the titration with N/IO KSCN.

assayed by the above method using five grams of t he oint ment.

( B ) ASSAY O F MERCURIAL OINTMENTl-Heat under a

I cc. KSCN solution = 0.01 g. mercury. (c) O I K T M E N T O F RED MERCURIC oxIDE2-This iS

I cc. N/IO KSCN = 0.0108 g. mercuric oxide. ( D ) OINTMENT OF MERCURIC NITRATE is assayed as

above described, using IO grams.

I n conclusion, the author wishes to thank Dr. Frederick W. Hey1 at whose suggestion the work of reviewing the standardization of these preparations was taken up.

THB UPJOHN COMPANY KALAMAZOO, MICHIGAN

ELECTROLYTIC DETERMINATION OF MERCURY IN MERCURY OLEATES

By B. L. MURRAY Received September 13, 1915

Owing t o the greasy nature of t he numerous oleates of mercury the determination of mercury in them by the older methods of analysis presents some difficul- ties. The necessary separation and removal of the oleic acid together with the tedious determination of mercury by the usual precipitation methods may perhaps have deterred some from assaying the oleates heretofore. The tendency has been t o take the oleates mostly on faith. I n our experience, however, a n effort has been made to get away from routine and endeavor to make a new application of the electro- ly t ic determination of mercury, already found so useful and satisfactory on other pharmaceutical products.

The method tha t is given below has been in use 1 This method is not as practical as the one given in the U. S. P 2 In assaying an ointment of yellow oxide of mercury which contains

only 0.8 per cent of the mercurial, it was found necessary first to remove the base with ether. I t was then possible t o obtain results approximately correct. i . e. 0.75 per cent.

in i ts present form about two or three years and in our hands proves accurate. One would hardly be- lieve quantitative results could be obtained if the mix- ture is observed just before the electrolysis. The apparatus, a cathode beaker, contains metallic mer- cury, toluene, hydrochloric acid IO per cent, and the oleate of mercury. Upon turning on the electric current, however, and almost as if by magic, this hetero- geneous mixture readjusts itself into orderly arrange- ment, and in a short time the mercury tha t was com- bined in the greasy oleate lies shining and bright on the bottom of the cathode beaker ready to be weighed.

METHOD-About 0 . 7 t o 1 . 0 gram of the oleate is weighed directly into a mercury cathode cup (such as a small beaker, capacity 50 t o 7 5 cc.). To this sam- ple there are added 15 t o 20 cc. of IO per cent hydro- chloric acid and 15 cc. of toluene. The cathode cup with its contents is placed within a somewhat larger crystallizing dish or beaker which later can be filled with cold water t o keep the temperature of t he reac- tion down as desired. After attaching the anode and making the connections in the customary way, elec- trolysis of this non-uniform mixture is begun, grad- ually and slowly increasing the current up t o 3 am- peres, using about IO minutes t o do it. The current (3 t o 3 . j amperes a t about 8 volts) is then main- tained for about 30 minutes, the anode rotating at about 800 revolutions per minute. As the electrol- ysis continues, the contents of the cup become heated nearly to the boiling point of some of the constituents, thus melting the mercury oleate. It is essential t ha t the mercury oleate should melt. If the liquid in the cathode cup becomes too hot and appears ap t t o boil over, i t should be cooled down by pouring water into the crystallizing dish or other surrounding ves- sel, bu t it should not be cooled down below 60' C. When the mercury is all deposited the cathode cup is washed out by siphonation in the customary way with water, after which the metallic mercury is washed with alcohol, dried with ether and finally weighed.

LABORATORY O F MERCK & C O M P A N Y

RAHWAY. N. J.

ELECTROLYTIC DETERMINATION OF BISMUTH IN BISMUTH 6-NAPHTHOL

By B. I,. MURRAY Received September 13, 1915

Another useful application of the electric current in analytic work has been found in the determina- tion of bismuth in bismuth @-naphthol. Aside from the electrolytic portion i t is only necessary to ignite the compound in order t o remove organic matter and dis- solve the bismuth oxide and metal thus formed in nitric acid. The resulting bismuth nitrate is then electrolyzed.

METHOD-A sample of 0 . 3 gram is weighed into a porcelain crucible and heated very gently t o decom- position of the @-naphthol. The crucible is finally heated to the full red heat of a Meker burner for 3 minutes to burn off the last traces of carbon. The residue resulting is yellow in color and is composed chiefly of bismuth oxide together with a small quan- t i ty of metallic bismuth. The crucible is placed in a

2 58 T H E J O U R N A L O F I i Y D U S T R I A L

small beaker and a mixture of 4 cc. of nitric acid (sp. gr. 1.4) and j cc. of water is added, after which i t is heated on a steam bath to complete solution. The solution is washed with distilled water into a mercury cathode cup, keeping the volume down to 20 cc. The cathode cup is conveniently made from a j o cc. Erlenmeyer flask. The 20 cc. solution is then electrolyzed under the following conditions:

CURRENT (maximum), 4 5 amperes at 6 volts REVOLCTIOXS PER MINUTE, 1000. TIME, 45 minutes

The initial application of the current is I ampere and this is followed by a gradual increase to 4 . 5 amperes. Some black masses are seen to form, but rapid rotation of the anode prevents the formation of a large quantity and all disappear. T h e n the black masses have entirely disappeared the rotation of the anode is stopped and the cathode is washed with distilled water by siphonation while the full strength of current is on. The electrolyte should be tested for bismuth with hydrogen sulfide. After z t o 3 washings with water, followed by alcohol, and then by ether, the mercury cathode is weighed. The increase in the weight of the mercury cathode is due to the bismuth which has been deposited on and amalgamated with the mercury.

LABORATORY OF M E R C K 8; COMPANY RAHWAY, X J

A N D E N G I N E E R I N G C H E M I S T R Y V O ~ . 8, SO. 3

ELECTROLYTIC DETERMINATION OF MERCURY IN MERCURY SALICYLATES

By B L MURRAY

Received September 13, 1915

A rapid and convenient method of determining mer- cury in mercury salicylates is herewith presented. It consists in a new application of the already well and favorably known electrolytic deposition of mercury. The method here given as used on salicylates of mer- cury has been in use about two years and has proved reliable.

About o 3 gram is weighed into the mercury cathode dish and dissolved in I O cc. of sodium sulfide solution (sp. g?. about I . IS). To this solution are added 2 0 cc. of I O per cent potassium hydroxide solution. The mixture is now electrolyzed using a current of I

ampere a t 7 volts until the mercury is completely deposited, usually about one-half hour being re- quired. The anode should rotate about 500 revolu- tions per minute. After the deposition the electro- lyte is decanted, the mercury is washed with water until free Erom alkalinity, then with alcohol, fifially with ether. and then weighed.

LABORATORY OF bIERCK 8; COMPANY RAHWAY, N J.

LABORATORY AND PLANT DETERMINATION OF SULFUR DIOXIDE AND SULFUR

TRIOXIDE IN FLUE GASES By R J. XESTELL AND E. ANDERSOX

Received January 1 5 , 1916

I n carrying on some experimental work recently on the gases issuing from the roasting furnaces a t one of the large Arizona copper smelters, a rapid, accurate and convenient method for the quantitative estimation of SO2 and SOs was of primary importance. The conditions of the work in hand demanded:

I-That the determination of both sulfur oxides should be made upon the same sample of gas.

2-That the time necessary for such determinations should be as short as possible in order t ha t any change in the composition of t he gases given off in consequence of varying conditions in the operation of the furnaces might be rapidly and continuously determined by one or two operators.

3-That t he apparatus required should not be too fragile or unwieldy in character bu t capable of con- venient transportation t o any poilit of t he smelter construction.

4-That the analytical operations necessary should be of such a nature as t o qdmit of ready performance in the field.

I n considering the various methods, applicable to this problem, previously proposed or employed by other workers and of which we have found any record, it was evident t ha t no one of them fulfilled all the require- ments of the present case.

h scheme proposed by Hawleyl for separating SO3 from SOz seemed t o be the most promising. This

1 Enp. Min. Jour., Nov. 23, 1912. p. 987.

consists of humidizing the gases with HzO vapor t o convert any SOa into the white fog of HzS04 and then passing them through a double filter paper held be- tween the large ends of two funnels. This mechan- ically retains the H2S04 and allows the SO2 to pass through. The HzS04 so caught is then determined by placing the filters in a small beaker with about j o cc. of water, adding a drop of methyl orange and titra- ting with standard alkali.

I n support of the accuracy of this method Hawley gives the following data of tests made by him in which known amounts of HzS04 were heated in a hard glass tube and the fume, mixed with air, passed through the filter and the acid so caught determined:

1 2 3 Grams HzSOi t a k e n . , , . , . . , , , , . , . Grams HzSOa found , , , , , , , , , , , , . Per cent found. , . , . , , , , , , . . , . . . .

0 . 0 6 4 0 . 0 6 0

0.050 0 . 0 3 4 0 , 0 4 7 0 . 0 3 2

93.7 94.0 9 4 . 1

We have made a series of similar tests in which accurately weighed amounts of H2S04 were heated in a Y-shaped hard glass tube and the volatilized acid drawn with a current of air through the “Hawley” filter. The HzSO4 remaining in the tube and also tha t caught on the filter were then determined. This gave exactly the amount of acid volatilized and re- covered. The following da ta were obtained:

1 2 3 4 5 Grams SOs t a k e n . . . . . , , . 0 . 5 7 2 0 . 0 9 8 9 0 , 0 7 0 8 0 . 0 2 3 0 0.0482 Grams SOa found . , , , . . . , 0 . 5 6 4 0 , 0 9 7 6 0.0692 0.0228 0 .0481 Percent found , . . . . . . , , . 98.6 9 8 . 7 97 .7 9 9 . 1 9 9 . 8

These figures show a considerably higher efficiency for the method than do Hawley’s and demonstrate it to be sufficiently accurate for general application.

To apply this method then to our work i t was neces- sary t o provide only for the estimation of the SO2