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Vol. 15, No. 6
INDUSTRIAL A N D ENGINEERING CHEiMIXTRY
NOTE-It is, of course, essential that enough nickel reagent t o completely precipitate the guanylurea be used and that sufficient time for complete precipitation be allowed. The filtrate from the nickel guanylurea should have a green color, showing the presence of an excess of nickel. If it does not have a gi-een color, add 5 cc. of the nickel reagent and allow to stand.
TEST11. AMMONIAI N ABSENCEOF CYANAMIDE-TOa 10-cc. portion of the solution add 1 g. of magnesium oxide which has been ground to a pulp with water, and heat to boiling. Identify ammonia by its odor or by use of litmus paper. NOTE-Under these conditions none of the ten nitrogenous forms, except ammonium salts and cyanamide, yield appreciable quantities of ammonia. If cyanamide is present it must be removed, as recommended in Test 12. If the findings of Test 11 are uncertain, repeat it as follows: Dilute a 50-cc. portion of the solution with 100 cc. of water, add 2 g. of magnesium oxide ground to a pulp, and boil the mixture in an ammonia distilling apparatus for just 15 min., absorbing the distillate in water. Add 2 drops of methyl red indicator and titrate the liberated ammonia with 0.1 N sulfuric acid. I N PRESEKCE OF CYANAMIDE-TOa TEST12. AMMONIA 25-cc. portion of the solution add 5 cc. of 10 per cent silver nitrate and then 5 cc. of 10 per cent caustic soda. Shake t o coagulate the precipitate, filter, and wash twice with cold water. Add to the filtrate 5 g. of magnesium sulfate dissolved in a little water, dilute to about 150 cc., and heat to boiling. Identify ammonia by the odor, by use of a piece of litmus paper, or by distilling into water, as directed in the note of Test 11. NOTE-cyanamide is completely precipitated by silver nitrate in caustic soda solution. The addition of the magnesium sulfate to the resulting filtrate, which contains an excess of caustic soda, precipitates magnesium hydroxide and gives the conditions of Test 11. TEST13. UREAI N ABSENCEOF CYANAMIDE-TOa 25-cc. portion of the solution add 1 drop of methyl red indicator, make exactly neutral with 0.02 N sulfuric acid or caustic soda as required, and then add just enough of the acid to impart a distinct pink color. Suspend 0.1 g. of soy-bean flour in 10 cc. of water by vigorous shaking for several minutes. Add a drop of methyl red indicator and make the suspension exactly neutral with 0.02 N acid or alkali. Add this suspension to the solution under examination and heat for 30 min. a t
Meeting of the American Electrochemical Society Edward Goodrich Acheson, whose achievements in the electrochemical field have made his name well known to all the world, was honored by the American Electrochemical Society by election to honorary membership in that body a t its twenty-first anniversary meeting, held a t the Hotel Commodore in New York, May 3, 4, and 5, 1923. According to F. A. J. Fitzgerald, who presented the account of the man and his work, Dr. Acheson’s outstanding characteristic and that which has contributed most to his success, is his ability to choose his objectives carefully and to drive straight to them without being sidetracked by side issues. Dr. Acheson was one of the founders of this Society. There were 250 in attendance a t the meeting. The secretary reported that the publication program of the Society had been brought up to date, and the treasurer’s report showed a healthy condition of finances. The Committee on Radioactivity recommended that an effort be made to collect all papers on this subject into one journal, preferably that of the Society. The Membership Committee reported a present membership of 1784, a net loss of 211 over a year ago. Symposia on “The Electrochemistry of Gaseous Conduction,” the leadership of Duncan MacRae; “Electrolytic Refining, under F. R. Pyne; and a round-table discussion of “Electric Furnace Brass Foundry Practice,” under Crosby, Lyon, and Elliott, were announced for the September meeting. Symposia on “The Utilization of Chlor,i,ne,” under A. H. Hooker, and on “Organic Electrochemistry, under C. J. Thatcher, were announced for the spring meeting of 1924. The next meeting will be held in Dayton, Ohio, on September 13, 14, and 15, 1923.
uncia
50”. (Color change, pink t o yellow, presence of urea.) Roughly determine the quantity of urea present by titrating the liberated ammonia with 0.02 N sulfuric acid, NoTEs-(~) The soy-bean flour is prepared by peeling and drying the soy beans, grinding, and screening through an 80mesh screen. The prepared enzyme is also satisfactory for this test. (2) The color change usually becomes apparent within 2 or 3 min. Sometimes the indicator is bleached during the incubation, in which case it is necessary to add another drop when the incubation is finished. (3) This test depends upon the conversion of urea to ammonia by the ureolytic enzyme. Of the ten nitrogenous forms listed in this scheme, only cyanamide interferes. the interference of cyanamide is due to the fact that a t incubation temperatures it may decompose to produce urea. Cyanamide solutions, however, are relatively stable when practically neutral, as in the present case, and unless very large amounts of cyanamide are present a positive result in Test 13 is conclusive fqr urea. If large amounts of cyanamide are present, a positive result in Test 13 should be confirmed by Test 14. If Test 13 is negative, pass on to Test 15.
TEST14. UREAI N PRESENCE OF CYANAMIDE-TO a 25-cc. portion of the solution add 2 cc. of strong ammonia and then 10 per cent silver nitrate, drop by drop, until no more precipitate is formed. Shake to coagulate the precipitate, filter, and wash the precipitate once with cold water. Add to the filtrate hydrochloric acid, drop by drop, until it is just acid, filter off the silver chloride, and wash once with cold water. Now add methyl red indicator, make the filtrate exactly neutral with 0.02 N alkali and acid, and proceed as in Test 13. NoTE-The cyanamide is removed as silver cyanamide and the excess silver is then precipitated as silver chloride. This procedure for the elimination of the cyanamide is chosen in preference to that employed in Test 12 because urea is carried down with the silver precipitate when the precipitation is made with silver nitrate and caustic soda.
TEST15. NITRATE(RINGTEsT)-Mix a S-cc. portion of the solution with an equal volume of saturated ferrous sulfate solution. Place the mixture in a test tube and add 2 cc. of concentrated sulfuric acid, pouring the acid down the side of the tube, held in an inclined position. (Brown ring, presence of nitrate.) The following officers were elected for the ensuing year: President: A. T.HINCKLEY Secretary: COLING FINK V i c e Presidents: LAWRENCE ADDICKS G. K . ELLIOTT HENRYHOWARD Treasure*: F. A. LIDBURY
Managers: F. M. BECKET C. B. GIBSON R. A. WITHERSPOON
Gifts to Chemists’ Club At the twenty-fifth anniversary of the Chemists’ Club, New York, on May 2, W. H. Nichols, one of the original members, took occasion to present the club with five hundred shares of stock in the Chemists’ Building Company, owners of the building in which the club is situated. The original issue oE stock of this company was 5000 shares, representing a total capitalization of $250,000, which was reduced by the will of Morris Loeb to about $175,000. This birthday present from Dr. hTicholsgives the club ownership of $116,700 of the stock now outstanding. The following officers were elected to serve for the coming year: Pvesident: F. J. METZGER Treasuuer: A. G ROBINSON Resident V i c e President: ALLEN Secretary: H. G. SIDEBOTTOM ROGERS Trustees: A. A. HOLXES,S K . R&ED Nonresident Vice President: E. R. WEIDLEIN
On account of the death of Mr. Reed between the time of balloting and the election, nominations to fill his office were called for from the floor and T. R. Duggan was elected. A second birthday present to the club on this occasion was given by A. G. Stillwell in the form of his part of the bond issue made by the club for acquiring the Annex.
