938
V O L . U M E 19, NO. 1 1
purified by the method of Kurschner and Hanak ( 5 ) and estimated by chromic acid oxidation according t o von Fellenberg (8).
B shows a filter of the Gooch type, of 12-mm. inside diameter and ca. 30-mm. over-all length. It has a bottom layer of No. 36 alone or covered by No. 80 and asbestos. For convenience during filtration a n extension tube of the same bore may be connected by rubber tubing. After removal of the asbestos layer, the filter and filter cake may be treated with solvents in a 50-ml. Erlenmeyer flask with a condenser. The liquid may be removed through the filter stick depicted in C, where the layer close to the constriction is No. 36, followed by KO.80, and then by asbestos. The bent construction is used for liquids attacking rubber, the filter stick being connected to the suction flask by a bent adapter. The filter resistance is considerably less than in the filter sticks described by Dunbar ( I ) and Kolthoff and Amdur ( 4 ) , where the asbestos is supported by only single glass bead. When the residue is to be titrated it may be blown out when the filter is wet or loosened by a glass pick. For the "sand" filter proper only alloxite has been used, in sizes 36, 60, 80, 100, and 120. On treatment with strong hydrochloric acid alloxite gives off some iron, and some of the aluminum
oxide is peptized. Before use large portions of alloxite were treated for several weeks a t room temperature and on the steam bath with new portions of hydrochloric acid. Then folIowed treatment with chromic-sulfuric acid, washing, and ignition a t a high temperature in a muffle furnace. The lack of complete insolubility causes uncertainty for a number of purposes. During the occupation of Norway it was impossible t o obtain samples of the powders of Jena gerateglas 20 and pure quartz for Jena filter crucibles. Where the powders serve only as supports for an asbestos mat, they need not be finely graded and may be made of crushed quartz after a simple sieving. LITERATURE ClTED
(1) Dunbar, R. E., IND. ENG,C H E b i . , ANAL.ED.,9, 355 (1937). Fellenberg, Th. von, Mitt. Lebensm. Hug., 21,385 (1930). Grossfeld, J., 2.Untersuch. A'ahr. Genussm., 42,29 (1921). Kolthoff, I. M.,and Amdur, E., IND.EKQ.CHEW,ANAL.ED., 12,177(1940). ( 5 ) Kurschner, K., and Hanak, A., 2. Untersuch. Lebensm., 59, 484 (1930). (6) Mayrhofer, J., 2. Untersuch. Nahr. Genussm., 4, 1101 (1901). RECEIVED January 17, 1947.
Apparatus for Distilling Aniline E. L. RUH AND J. L. ROSSETTIE Standard Oil Development Co., Standard Znspection Laboratory, Bayonne, N. J . A P P R O V E D procedure ( I ) for determining the aniline point of petroleum products requires that the aniline be distilled on the day of use, the f i s t and last 10% being discarded. Aniline is a highly toxic material, particularly when its vapor is inhaled, and the apparatus described in this report was devised to ensure minimum danger as well as maximum convenience in distilling this reagent. The apparatus illustrated is used as a complete assembly and is taken apart only for periodic cleanings. All connections are made by means of ground-glass fittings, and the connecting parts are held tightly together by means of small steel springs attached to hooks fused on the glass. The flask is a stock 250-ml. flask modified with an enlarged outlet, a removable filling arm, and a stopper. The condenser has the usual outer jacket inner tube, and adapter all made in a single piece. In the top of the adapter section is a small side arm, which is attached to one of two available water aspirators by means of a
A 12I)(QIco"sER
ENLARQED VIEW OF SECTION &A
piece of rubber tubing containing a glass T-piece. The receiver is a graduated cylinder of 100-ml. capacity, made of actinic red glass, with a stopcock a t the bottom. In the operation, a small mark is made on the bulb of the distillation flask, to indicate the level of 100 ml. The filling arm is fitted into the distilling flask with the lower end dipping into a bottle of aniline. The water aspirator is turned on and a finger is placed over the open end of the T-piece and left there until 100 ml. of aniline have been drawn into the flask. The bottle of aniline should be removed and an empty beaker held below the filling arm. The finger may then be removed from the T-piece. The filling tube is removed from the distilling flask and inserted in the filter flask. Water is poured into the beaker and the filling arm thoroughly washed. The flask is stoppered and heat is applied, preferably from an electric heater. When the first 10-ml. portion has collected in the receiver, it is drawn off into a small beaker and discarded, and the beaker is immediately washed with water. Heating is continued until some 78 ml. of aniline have collected in the receiver. A t all times, water is kept running through the aspirator connected to the adapter to remove any aniline vaDors from the vicinity of the opkrator. When the apparatus has cooled completely, TO FIRST the stopper of the distillation flask is removed, the filling arm, which is still connected to the suction flask, is inserted in the distillation flask, and the aniline remaining in the flask is drawn off by means of suction from the second aspirator. The filling arm is then withdrawn from the distilling flask, protected with a beaker, and rinsed with water as before. The actinic red glass of t'he graduated receiver protects the distilled aniline from the characteristic darkening caused by exposure t,o light. This makes it possible to withdraw test portions direct from the receiver, which serves the joint purpose of a measuring graduate and a storage receptacle. The use of the aspirator prevents any escape of aniline vapors into the atmosphere, and the general procedure for charging the flask and withdrawing test portions from the graduated receiver minimizes the possibility of contact of liquid aniline with the skin of the operator. LITERATURE CITED
ANILINE DISTILLATION APPARATUS
Figure 1
(1) Am. Soo. Testing Materials, Tentative Standard Method D611-46T. RECEIVED February 7, 1947.
