SEPTEMBER 15, 1940
ANALYTICAL EDITION
responding weights of ruthenium were 10.27 and 11.35 mg. The weights of ruthenium metal recovered were 10.18 and 11.41 mg. This method, however, proved to be tedious. 2. Ruthenium tetroxide was distilled into a hot acidified solution of thioglycolic p-aminonaphthalide. The rutheniumorganic complex precipitated immediately, but because of mechanical difficulties the method is not recommended. 3. An acidified 10 per cent solution of potassium iodide was used as an absorbing solution. Too much difficulty was encountered in removing iodine from the ruthenium triiodide.
563
recovered directly from this solution by precipitation with the thioglycolic 0-aminonaphthalide. The hydrogen peroxide, however, must be free from acetanilide. An aqueous solution of sodium hydroxide may be used as a n absorbent and the ruthenium recovered quantitatively, but the procedure is lengthy.
Literature Cited
Summary
(1) Berg, R., a n d Roebling, W., Angew. Chem., 47, 404 (1934). (2) Gilchrist, R . , Bur. Standards J . Research, 3, 993 (1929); 12, 283
Ruthenium can be quantitatively precipitated from a 0.2 to 0.5 N hydrochloric acid solution by means of thioglycolic 0-aminonaphthalide. A cold 3 per cent solution of hydrogen peroxide quantitatively absorbs ruthenium tetroxide, and the ruthenium can be
(1934). (3) Howe, J. L., a n d Mercer, F. N., J . Am. Chem. Soc., 47, 2927 (1925). (4) Kienitz and R o m b o c k , 2.anal. Chem., 117, 241 (1939). ( 5 ) Krauss, F., a n d Schrader, G., 2. anorg. Chem., 176, 385 (1928). (6) Ransohoff, F., and Gutbier, A., Ihid., 45, 243 (1905). (7) Ruff, O., and B o r n e m a n n , F., Ihid., 65, 429 (1910).
Apparatus for Semimicrodetermination of Carbon and Hydrogen CARL NIEMANN AND VANCE DANFORD California Institute of Technology, Pasadena, Calif.
T T IS the purpose of this communication to describe, in condktail, the construction and operation of a n
1 siderable
apparatus specifically designed for the semimicrodetermination of carbon and hydrogen in all types of organic compounds.
Furnace Assembly COMBUSTION-ZONE FURNACE. A piece of 0.625-inch (1.59cm.) copper rod, 0.875 inch (2.22 cm.) long was turned down to a diameter of 0.375 inch (0.95 cm.) for a distance of 0.125 inch (0.32 cm.) from one end and the cylinder of lesser diameter was threaded. A seamless nickel tube, 0.531 inch (1.35 cm.) in inside diameter, 0.688 inch (1.75 cm.) in outside diameter, and 10.25 inches (25.65 cm.) long was drilled and tapped at its mid-point, the copper rod was screwed into the opening, and the nickel tube was reamed out, so as t o remove the portion of the copper rod protruding into the interior of the tube. A 0.438-inch (1.11-cm.) hole was drilled axially into the copper rod to a depth of 0.25 inch (0.64 cm.). From the bottom of this hole, a 0.25-inch (0.64-cm.) hole was drilled to a depth of 0.75 inch (1.91 cm.), measured from the top face of the rod, or to the projected external circumference of the nickel tube. The tuhular part of the assembly was sheathed with a double layer of mica and a single layer of 0.063-inch (0.16-cm.) asbestos cord, the latter bring wound to within 0.25 inch (0.64 cm.) of each end of the nickel tube. (In this operation a sheet of first-grade mica, free of flaws, is split along the cleavage plane until the thickness of the sheet is reduced to the point of necessary flexibility.) Using the asbestos cord as a spacer, the sheathed nickel tube was wound with 158 inches (401.32 cm.) of No. 28 Chromel A resistance wire. I n this operation sufficient wire was taken, 278 inches (706.12 cm.), to leave 48 inches (121.93 cm.) unwound a t each end. I n winding the section of the tube bearing the copper well it was found convenient to place a square-sided U-shaped piece of wire, covered with porcelain tubing, around the well with the open end of the U facing one end of the nickel tube. The wire in this region was wound back and forth over the porcelain arms. When the windings were in place the U was closed by inserting a second U, with short exposed wire arms, into the free ends of the porcelain tubes of the first U. The assembly was covered with a second layer of 0.063-inch (0.16-cm.) asbestoscord and the 48inches (121.92 cm.) of wire remaining a t each end were wound in the interstices of the second layer of asbestos cord for a distance of 1.25 inches (3.18 cm.) from each end. After securing the ends of the winding with asbestos cord, the wires were brought to the center of the tube in a single turn and anchored to each other by means of a small double-hole porcelain insulator. From here to their point of exit from the body of the furnace, the wires
were insulated with short lengths of small-diameter porcclain tubing. Two end plates, one 4 X 4 inches (10.16 X 10.16 cm.), the other 4 X 5 inches (10.16 X 12.7 cm.), werc cut from 0.5-inch (1.27-cm.) Transite board and in the center of the square plate a 0.531-inch (1.35-cm.) hole was drilled. This hole was countersunk so as to produce a shoulder 0.281 inch (0.71 cm.) deep and a diametcr equal to that of the nickel tube and all its windings. Four 0.219-inch (0.56 cm.) holes were drilled at a point on the diagonals 0.5 inch (1.27 cm.) in from the corners of the square and were countersunk on both sides to a depth of 0.125 inch (0.32 cm.) and a diameter sufficient to accommodate a standard 0.188inch (0.48-cm.) brass hexagonal nut. A circular groove 3.5 inches (8.89 cm.) in diameter, 0.063 inch (0.16 cm.) wide, and 0.25 inch (0.64 cm.) deep was cut on the side of the plate bearing the countersunk portion of the central orifice. The rectangular plate was divided into a 4 X 4 inch (10.16 X 10.16 cm.) square and a 1 X 4 inch (2.54 X 10.16 cm.) rectangle and the square portion was machined exactly as described for the square plate. Two metal binding posts were centrally located on the inside face of the 1 X 4 inch (2.54 X 10.16 cm.) rectangle and by means of 0.063-inch (0.16-cm.) holes, drilled in the end plate, the leads of Chromel wire were brought out of the interior of the furnace and secured to the binding posts. A cylinder 3.5 inches (8.89 em.) in diameter and 10.25 inches (26.04 cm.) long, with a 0.438-inch (1.11-cm.) hole at the mid-point, was formed from a sheet of 26-gage stainless steel and the lap joints were secured by rivets. With the aid of four 0.188-inch (0.48-cm.) brass tie rods, 10.75 inches (27.31 cm.) long and with 10-32 threads on both ends, the furnace was assembled and the space betwecn the nickel tube and the stainless steel tube was filled with asbestos pulp. During this operation access to the copper thermocouple well was secured by inserting a glass tube through the 0.438-inch (1.11-cm.) hole in the steel jacket and in the 0.438-inch (1.11-cm.) hole of the copper well. The glass tube was cut off flush with the exterior surface of the jacket and was kept in place, in the copper well, with an asbestos gasket. In the assembly four legs constructed from a 0.125 X 1 inch (0.32 X 2.54 cm.) hot-rolled iron bar were attached to the inside of the end plates with nuts held on brass tie rods. These legs xere 7 inches (17.78 cm.) high, were bent a t right angles to form a foot 1.5 inches (3.81 cm.) long and, at the top, were cut away so as not to interfere with the steel jacket. Each foot was drilled and tapped in its central portion for a 6-32 thread. LEADPEROXIDE-ZONE FURNACE. A shoulder 0.25 inch (0.64 cm.) wide and 0.375 inch (0.95 cm.) deep was cut on each end of a 2-inch (5.08-cm.) copper rod 3.5 inches (8.89 cm.) long. After drilling a 0.688-inch (1.75-cm.) hole axially through the cylinder, H second hole, 0.375 inch (0.95 cm.) in diameter, was drilled ra-
564
IKDUSTRIAL AND ENGINEERIIYG CHEMISTRY
VOL 12, NO. 9
dially, a t the mid-point of the cylinder, until the axial hole was 0-35 ohm, SO-watt, model J , Ohmite rheostat; an SO-ohm fixed resistance, made by winding 148 inches (375.92 cm.) of No. 30 intercepted. Both holes were reamed out for press fits; into Chrome1 A wire on a 0.125-inch (0.32-cm.) porcelain tube; the axial hole was pressed a nickel tube 0.531 inch (1.35 cm.) in inside diameter, 0.688 inch (1.75 cm.) in outside diameter, and 3 toggle switches; 2 nonmetallic binding posts; and 2 single 3.5 inches (8.89 cm.) long, and into the radial hole a copper tube banana jacks were mounted on the switchboard and the apparatus was wired as indicated in Figure 2 . All connections were 0.25 inch (0.64 cm.) in inside diameter, 0.375 inch (0.95 cm.) in The largest outside diameter and 1.625 inches (4.13 cm.) long. made with KO. 14 insulated multistrand copper wire. The cylindrical surface was sheathed with a double layer of mica and thermocouple for the combustion-zone furnace was made from wound with a single layer of 0.063-inch (0.16-cm.) asbestos cord, KO.22 Chromel P and Alumel wire. For a distance of 2 inches the latter extending to within 0.25 inch (0.64 cm.) of the ends of (5.08 cm.) from the silver-soldered ball tip of the hot junction the mires were insulated with pieces of two-hole porcelain tubing and the cylinder. Then 271 inches (688.34 cm.) of S o . 30 Chromel A from this point to the point of attachment, with silver solder, to wire were wound on the sheathed cylindrical surface, using the the jacks on the switchboard, the wires were covered with spaasbestos cord as a spacer. As in the construction of the combustion-zone furnace sufficient wire, 72 inches (182.88 cm.), was left ghetti insulation. It is important that the jacks be mounted close together, to minimize any difference in the temperature of free, a t each end, for a subsequent end-zone winding. After the first winding was in place the assembly was covered with a second the cold junctions. The leads were long enou h so that the therlayer of 0,063-inch (0.16-cm.) asbestos cord and the 72 inches mocouple could be placed in the well of the fead peroxide-zone (182.88 cm.) of wire remaining a t each end were wound on the furnace, thereby permitting comparison between the thermocylinder for a distance of 1inch (2.54 cm.) in from each end, The couple and the mercury-in-glass thermometer, normally used with this furnace. A recalibrated Weston No. 801 microammeter, 80windings were secured, and the leads anchored to each other and insulated as described above. ohm internal resistance, was used with the thermocouple, and Two end plates, one 4 X 4 inches (10.16 X 10.16 cm ), the other as only one meter is needed for a number of furnaces the instru4 X 5 inches (10.16 X 12.7 cm.), were cut from 0.5-inch (1.27-cm.) ment was mounted as an individual unit. The leads from the Transite board and machined as described for the end plates of meter w-ere fastened to two banana plugs which fitted the jacks the combustion-zone furnace, with the exception that the central mount'ed on the switchboard. It is advisable to have the plugs orifice was 1.25 inches (3.18 cm.) in diameter and the shoulder, and jacks of different colors, so as to avoid damage to the meter. 0.281 inch (0.71 cm.) deep, was of sufficient diameter to allow free An indication of the thermal characteristics of the furnace access of the completely wound copper block. A 0.375-inch (0.95-cm.) hole was drilled in the center of a piece of 26-gage stainassembly is given in Figure 3. less steel sheet, 3 inches (7.62 cm.) wide and 11.625 inches (29.53 cm.) long, and from each corner a piece of metal 0.438 X 0.875 The data presented in this plot were obtained by placing a combustion tube, bearing a glass thermocouple well, in the furnace inch (1.11 X 2.22 cm.) was removed. The sheet was formed into a cylinder and the 0.625-inch (1.59-cm.) lap joint secured by and determining the temperature a t the various points with a rivets. Two legs, made from 0.125 X 1 inch (0 32 X 2.54 cm.) Cliromel P-Alumel thermocouple. The thermocouple well exhot-rolled iron bar, were fastened to the inside of the end plates tended throughout the entire length of the combustion tube and with 8-32 bolts (see Figure 1). In order to facilitate the alignthe space bet7veen thewell and the walls of the tubewas filled with ment of the lead peroxide-zone furnace with the combustionsand. During the tests the lead peroxide-zone furnace was zone furnace, the legs were made in two sections and joined with maintained at 200" C. (temperature in thermometer well) and 0.25-inch (0.64-cm.) cap screws, 1 inch (2.54 cm.) apart, in 0.375the combustion-zone furnace a t 600' C. (temperature in thermoinch (0.95-cm.) holes. The foot of eachlegwas drilled and tapped in couple well). The temperature of the lead peroxide-zone is constant throughout its entire length, and in passing from the lead its central portion for an 8-32 thread. The furnacewas assembled peroxide-zone furnace to the combustion-zone furnace a 400' with the aid of 0.188-inch (0.48-cm.) brass tie rods and the space temperature gradient is established within a distance of 9 cm. between the block and the jacket wm filled with asbestos pulp. AUXILIARY HEATERFOR CONSTRICTED END OF COMBUSTION Furthermore, the temperature of the main combustion zonei. e., the copper oxide zone-is at no place less than 500' and for TUBE. Two coils, 0.125 inch (0.32 cm.) in diameter and 0.25 inch more than 50 per cent of its length is approximately 600' C. (0.64 cm.) long, each containing 6 turns of No. 30 Chrome1 A wire, were linked with a 6-inch (15.24cm.) length of No. 22 insulated multistrand copper wire and the ends of the coils were connected, in series, to a No. 22 two-wire flexible cord. The Chromel-copper connections were made with silver solder. FURNACE ASSEMBLY. The two furnaces were mounted on a wood base, 11.5 X 32 inches (29.21 X 81.28 cm.), top ed with 0.25-inch (0.64cm! Transite board. All holes bearing bolts or nuts were countersunk, so as to leave the undersurfaceof the base free of protuberances. I n mounting the lead perd oxide-zone furnace, 0.375inch (0.95-cm,) bolts in 0.438-inch (1.11-cm.) holes facilitated final alignment. R The exact disposition of the furnaces on the base is not critical and sufficient information about this point can be obtained from Figure 1. A Transite switchboard, 0.25 X 5 X 9.5 inches (0.64 X 12.7 X 24.13 cm.), was fastenedtothebase, between the legs of the combustionzone furnace, with two 70' an le irons. A Jefferson 8voft bell transformer; a 0-50 ohm, 25-watt, model FIGURE 1. FURNACE ASSEMBLY H, O h m i t e r h e o s t a t ; a
SEPTEMBER 15, 1940
Tube Heater
ANALYTICAL EDITION
200° 5 Zone e 2 2 SL
-
combustion tube 2 cm. in from the unconstricted end. The body of the tube was made of Pyrex KO.172 glass and the capillaries were made of standard Pyrex glass. The absorption tubes were those recently described by Prater ( 2 ) . Anhydrone and Ascaritewere used for absorbing the water and carbon dioxide formed during a combustion. The terminal drying tube, charged with Anhydrone, was similar to Sargent No. 5-49645 except that the outside diameter was 12 mm. and the length 10 cm. The Mariotte flask assembly was identical with that described by Pregl(3,4) and the remainingitemswerestandard pieces of apparatus. All connections were made with pure gum tubing, or stoppers, treated as directed by Pregl(3,4). COMBUSTIOSTRAINAsSEMBLY. In keepingwith the ~llOV.+ aim towards a compact and portable apparatus, the entire combustion train was mounted on the base bearing the furnaces. Oxygen was conveyed to the pressure regulator through a 0.125-inch (0.32-cm.) brass pipe bearing hose connectors at both ends. Union of the horizontal section, 33 cm., with the vertical section, 25 cm., of pipe was made through a 0.125-inch (0.32-cm.) tee. The assembly was fastened to the base by screwing one end of a threaded brass rod into the bottom of the tee and bolting the other end to the base. Near the inlet end a 6-32 bolt was soldered to the pipe and the shank of the bolt secured to the base by nuts above and below the Transite top. A receptacle for the pressure regulator was made by bolting to the base a piece of wood, 10 cm. square and 1.5 cm. thick, bearing a hole of sufficient diameter to accommodate the foot of the cylinder. Two 0.313-inch (0.79cm.) rods, 50 cm. high, were attached near each end of the base and horizontal sections of 0.313-inch (0.79-cm.) rod were fa
