INDUSTRIAL AND ENGINEERING CHEMISTRY
778
with fatty acid prior to incorporation had a much greater effect on the working properties than the addition of the same amount of fatty acid to the compound during milling. Surface treatment of the finer pigment with fatty acid resulted in a marked increase in the tubing rate and softness of the master batch. With the coarser oxide the resulting increase in the tubing rate of the rubber batch was slight but the increase in plasticity was obtained. TABLE 11. EFFECT OF VARIATIONS IN OF THE SURFACE Com-
pound 1 2 3 4
GI 59.08 64.57 82.36 52.23
iM
G2M
1.54 1.35 0.71 2.19
38.4 47.9 116.0 23.8
Compound 5
6 7 8
THE
NATURE
GZ
M
83.71 96.56 99.56 83.47
0.95 0.66 0.53 0.96
GZM 88.2 146.5 188.5 86.9
In the course of this investigation, experiments were made with samples of carbon black, precipitated whiting, ground limestone rock, and clay; while it was not possible to control the size and surface properties as was done with the zinc oxides, the general conclusions are the same. The processing properties improve as the particle size of the pigment increases if the surfaces are similar; if the pigments are coarse enough, the nature of the surface will be of minor importance in determining the processing quality but the finer materials such as certain precipitated whitings are highly sensitive to changes in the surface. I n this connection, some results obtained with channel-process carbon blacks may be of interest. Five' different carbon blacks were selected, representing a wide range of yiorking properties of this pigment. The samples were milled into the rubber with 55 parts of pigment to
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100 parts of rubber and 4 per cent of softener; check batches were prepared with each pigment. The following results are the average values obtained for each pigment on the tubing machine and demonstrate that Considerable variation exists in the working properties of these carbon blacks: Carbon Black 514 522
G, 10.41 16.71
Carbon Black 711 774 775
Gz 23.71 20.08 18.00
Infrared transmission curves were also measured for suspensions of each of the compounds and are shown in Figure 2. So far as it is possible to determine bv this method, no significant differences in particle size are indicated in this series of pigments. The application of the infrared transmission method in the determination of the size characteristics of carbon blacks was discussed in the previous paper (1). The average diameter of carbon blacks 514 and 775 was also measured by counting the number of particles in a Nujol suspension of the compounds, ueing the ultramicroscope according to the procedure of Gehman and Morris (9). The values obtained were within the experimental error of the method. These data indicate that the difference in tubing characteristics of these blacks results from differences in the nature of their surfaces rather than from differences in particle size.
Literature Cited (1) Gamble and Barnett, IND.ENG.CHEM.,Anal. Ed., 9, 310 (1937). (2) Gehman and Morris, Ibid., 4, 157 (1932). (3) Nellen, IND.EKG.CHEM.,29, 886 (1937). RECEIVED April 2, 1938. Presented before the meeting of the Division of Rubber Chemistry of the American Chemical Society, Detroit, Mioh., March 28 and 29, 1938.
Toxicity of Ethylene Imine JAMES P. DANEHY, Harris-Seybold-Potter Company, Cleveland, Ohio DANIEL J. PFLAUM, Regis College, Denver, Colo.
A
LTHOUGH ethylene imine was first prepared fifty years ago, very little work has been done with it, largely because of the difficulty of preparation. The recently reported synthesis of Wenker (3) is very satisfactory, despite rather low yields, and it is to be expected that considerably more research will be done on this interesting cyclic amine in the near future. It would be well, therefore, to bring to the attention of prospective handlers of this substance one of its important properties-toxicity. Shortly after the discovery of ethylene imine, its physiological action on guinea pigs was investigated by Ehrlich; his results were reported in papers by Gabriel (2) and by Duden and MacIntyre (1). Doses of 0.03 gram of ethylene imine hydrochloride per kg. of body weight caused death in 10 hours; doses of 0.015 gram caused death in 24 hours. Recent experiences in the laboratories of the writers have indicated that ethylene imine is definitely toxic to human beings when vapors (vapor pressure a t room temperature) are inhaled for short periods (2 to 3 minutes). It is also possible that allowing the liquid to come in contact with the skin will cause poisoning, although this condition has not occurred independently in the several cases observed. In one case a worker became ill when inadvertently he got one drop on his tongue, although he immediately rinsed his mouth thoroughly. The symptoms are quite definite. No discomfort is ex-
perienced during exposure. Two hours later vomiting begins and is repeated several times (three to eight times) a t intervals of about 30 minutes. The epithelium of the mouth and throat becomes inflamed and edematous, the uvula in particular swelling to about twice normal size. The eyes also become very inflamed. The symptoms disappear in from 1 to 2 days and apparently leave no ill effects. The following experiment was performed to determine the symptoms of serious poisoning on mammals: Two drops of the amine, dissolved in 0.5 ml. of water, were injected into the right shoulder of a healthy adult cat. Within one hour the hind quarters were paralyzed and the animal's senses (sight and hearing) were very dull. Ten hours later the animal died. An autopsy showed the stomach and kidneys to be alkaline in reaction. When proper precautions are exercised, ethylene imine can be used in the laboratory over long periods of time without any discomfort.
Literature Cited (1) Duden and MacIntyre, Ann., 313, 72 (1900). (2) Gabriel, Ber., 21, 2669 (1888). (3) Wenker, S. Am. Chem. SOC., 57, 2328 (1935).
RECEIVED May 6, 1938.
