546
1
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY.
sufficiently high temperature, changes into B , then into C. All varieties of A , whether they be liquid, pasty or solid, are still soluble in alcohol or acetone or in caustic soda, and behave as true resins. Solid A is characterized by the fact that it is solid at ordinary temperatures, but melts if moderate heat is applied and stronger application of heat makes it infusible and insoluble, by transforming it into B or C. Bakelite B is an intermediate solid product. I t is neither so hard nor strong as C, and may be easily mistaken for Solid A , but it is different from the latter on account of its insolubility. Furthermore, it is infusible, although the application of heat may temporarily soften it, without, however, bringing it into fusion. Solvents do not dissolve it, but some of them, like phenol or acetone, may soften it or swell it, without bringing it into solution. B is specially characterized by the fact that although it is infusible, it will soften under the action of heat and then will mold and weld together if pressed in a hot hydraulic press. The latter fact differentiates it clearly from C. Bakelite C is the final product, resulting from the application of heat to A or B,and may be considered as a chemical polymer of B resulting from a multiple molecular grouping. I t is no longer a resin, because it lacks all the chemical characteristics of a resin, although physically it may resemble amber. I n pure form, and if made from the first member of the phenol group, its chemical formula is represented by C,,H,,O,. Although the preparatory work connected with the industrial side of the process has been going on with strenuous application since 1907,it was thought advisable not to jeopardizeeverything by a too hasty, broadcast introduction, before each industrial use had been studied for a sufficiently long time, on a practical commercial scale. This conservative way of proceeding is not always followed by those who are not sufficiently aware of the enormous distance that exists between a laboratory conception and the practical utilization thereof. In the meantime, Bakelite has been used continuously during the last two years, especially for electrical purposes, while undergoing the test of time and the critical observations of everyday practice under the eyes of specialists, This work has been conducted on a sufficiently large scale to remove all doubts as to the practical side of the question. Thus Bakelite is no longer a laboratory experiment but a product well tried in several industries. Bakelite technical insulators, as well as pump valves, and other molded goods are now obtainable from several licensees of the General Bakelite Company, and some electrical manufacturers have begun the practical impregnation of coils, dynamos, motors, etc. The General Bakelite Company will limit more specially their attention to the chemical side of the process manufacturing the raw materials, just far enough that the users thereof can limit their attention to the mechanical side of the problem. A factory plant i; being equipped now a t Perth Amboy, N. J., but in the meantime the manufacturing is being carried on in Yonkers. In our November number, 1910, page 478, we have published a list of the United States patents, thus far issued. An information book on practical uses of Bakelite can be obtained by applying to the General Bakelite-Company, -100 William Street, New York, N. Y.
THE USE OF IMMISCIBLE SOLVENTS. There are several methods in use by food chemists, some of them recognized as official by the A. 0. A. C., which involve the use of immiscible solvents, as for instance, the modified Hess and Prescott method for determining vanillin in vanilla extracts, and Bigelow’s modification of the LaWall and Brad-
Dec., 1910
shaw method for the estimation of benzoic acid in food products. It is a well-known fact that ether and chloroform which contain water or are in contact with water will take up appreciable amounts of inorganic salts. This has been found to constitute a continual source of error in such determinations. In the Hess and Prescott method for vanillin the extraction is made with ether from a solution which contains more than z per cent. bf ammonium chloride. With utmost care in the separation, the residue from the ether solution will still give a strong test for chlorides. Similarly in the method for benzoic acid, where extraction is made from a saturated salt solution with chloroform, considerable quantities of salt will invariably be found in the residue. The writer has found it necessary in all cases to take up the residue with a little anhydrous ether, and again evaporate, to secure anything like concordant results. ROE E. REMINGTON. AGRICULTURAL COLLEGE,NORTHDAKOTA.
MAKING SAMPLE ALLOYS. Those of us who are teaching qualitative analysis frequently find it difficult to obtain any number of different samples of industrial products. This has been, in my case, especially true of alloys of the more modern types such as ferro-chrome, nickel, steel, etc., which it is very desirable for the student to have practice on. I n case of these alloys it has been possible to make them with very little consumption of time. Black thermite (iron oxide and finely ground metallic aluminium) can be readily obtained. This, when placed in a common assay crucible, mixed with the element or elements with which it is wished to,alloy the iron, and ignited in the usual way by means of a fuse of magnesium ribbon and an igniting mixture of finely powdered aluminium and sodium peroxide, generates sufficient heat to form a homogeneous button of the alloy desired, in the bottom of the crucible. If alloys, which do not contain iron, are desired, equally good results can be obtained by making mixtures of the oxides of the required metals in the proper proportions with metallic aluminium and igniting as before. I have found alloys made in this way very satisfactory for qualitative analysis and that it is possible to make them with a very small consumption of time. R. C. BENNER. UNIVERSITY OF
h i z o m , TUCSON.
LABORATORY METHODS FOR ORGANIC NITROGEN AVAIL ABILITY. MODIFIEDALKALINEPERMANGANATE METHOD. As used by C. H. JONES,Vermont Station.
Total Orgafiic Nitrogen Basis.-Weigh an amount of material equivalent to 50 milligrams organic nitrogen into a 600 cc. Kjeldahl distillation flask. Add 20 cc. of water and 100 cc. of alkaline permanganate solution ( 2 5 grams pure KMnO, and 150 grams NaOH separately dissolved in water, the solutions cooled, mixed, and made to bulk of one liter). Connect with an upright condenser to which a receiver containing standard acid has been attached. Digest slowly (below distillation point) for 30 minutes. Gradually increase temperature and boil until 95 cc. of distillate are obtained; titrate as usual. Make a correction for any ammonia contained in the sample. During the digestion an occasional gentle rotation is desirable, and if the material shows a tendency to adhere to the sides of the flask during the distillation, the same procedure is advised. The per cent. of nitrogen obtained on the above 5 per cent. basis x z o = per cent. availability. 2. Water-insoluble Nitvogen Basis.-Weigh an amount of I.
