INDUSTRIAL AND ENGINEERING CHEMISTRY
5 14
D,
= molal diffusivity, gram moles/(cm.)(sec.)
e uilibrium water, weight per unit weight of bone-dry stock absolute humidity, weight per unit weight of %nk$ii; H corresponds to the main body of the air, H, to saturation at the wet bulb temperature, H, to saturation at the surface temperature in the constant rate period, and H‘ to the boundary between the air film and the main body of the air J = proportionality constant R = drying coefficient, in units of the reciprocal of time M A , Mg = molecular weight of diffusing gas and nondiffusing gas, respectively N A = moles transferred per unit time P = ressure of liquid CJ = [eat transferred, B. t. u. Re = Reynolds number T = temperature of liquid U = heat transfer coefficient V = volume W = weight a = surface area per unit volume 6 = sensible heat factor d = diameter f = function relating to falling-rate period h,, h,, h ~h ,~ = , heat transfer coefficient, by conduction and convection, by radiation, for the gas phase, and for the liquid phase, respectively I%, k’, k~ = transfer coefficient as Ib./sq. ft./atm., IbJsq. f t . / unit humidity difference, and lb. moles/sq. ft./atm., respectively Im = logarithmic mean 7n = weight ratio of bone-dry air to bone-dry stock p g = partial pressure of nondiffusing gas p a , p’, pi = partial pressure of diffusing gas, in the main body of the as, at the boundary between the main body and the gas Elm, at the liquid gas interface, respectively P, = saturation pressure at wet-bulb temperature q = rate of heat transfer, B. t. u./hr. re, rot, r/ = resistance to mass transfer, for the turbulent core using pressure units, for the turbulent core using humidity units, and for the laminar film, respectively T = over-all resistance r2!,rs,rW = latent heat of evaporation r,, = resistance to heat transfer in turbulent core s , s’ = humid heat E
VOL. 30, NO. 5
t,, ta, t’,
=
w
z a ,6
t i , t” = temperature of wet bulb, of saturation, at the boundary between turbulent core and laminar film, at the liquid-gas interface, and of the surroundings, respectively = rate of flow of bone-dry air through dryer, weight per unit time = distance
= = = =
h,
+ h,!h,
proportionality constant y rate of drying, grams/sq. cm. X thermal conductivity 0 = time p = weight of bone-dry stock per unit original volume 7 , TO, T~ = total moisture content, weight per unit weight of bone-dry stock; T corresponds to e, 70 to the original time, and T~ to. the critical point, respectively p = viscosity w = mass of gas-vapor mixture transferred by convection
Literature Cited (1) Arnold, J. H., Phusics, 4, 255, 334 (1933). (2) Chilton, T. H., and Colburn, A. P., Iivn Eao. CHEM.,26, 1183 (1934). (3) Comings, E. W., and Sherwood, T. K., Ibid., 26, 1096 (1934). (4) Gilliland, E. R., and Sherwood, T. K., Ibid., 26, 516 (1934). (5) Hougen, 0. A., and Ceaglske, N. H., Ibid., 29, 805 (1937). (6) Kamei, S., Minuno, S., and Shiomi, S., J. SOC. Chem, I n d . (Japan), 38, Suppl. Binding 456-73B (1935). (7) McCready, D. W., and McCabe, W. L., Trans. Am. Inst. Chem. Engrs., 29, 131 (1933). (8) Mark, J. G., Ibid., 28, 107 (1932). (9) Murphree, E. V., IND. ENQ.CHEM., 24, 726 (1932). (10) Sherwood, “Absorption and Extraction,” p. 5 5 , New York. McGraw-Hill Book Co., 1937. (11) Sherwood, T. K., IND. ENG.CHEM.,21, 976 (1929). (12) Ibid.. 22. 132 (1930).
5 ) Walker, Lewis, McAdams, and Gilliland, “Principles of Chemical Engineering,” 3rd ed., p. 593, New York, McCraw-Hill
Book Co.. 1937. REPXZIVBD January 24, 1938.
Dermatitic Properties of Tung Oil M. W. SWANEY Ellis Laboratories, Inc., Montclair, N. J.
T
HIS paper is the result of a severe case of dermatitis contracted by a worker in the varnish laboratories;
this irritation was attributed to tung oil. I n view of the widespread use of tung oil in paint and varnish manufacture, a few explanatory remarks should be made. It is not to be construed from this discussion that tung oil is a notoriously insidious material, nor are any aspersions to be cast upon its efficacy as a paint and varnish base. On the other hand, only a small minority of persons who possess the necessary allergic sensitivity are likely to be affected, and then probably only by the heated oil. By the vast majority, this oil can be handled with impunity. There would appear to be no danger a t all in handling or using the finished tung oil varnishes or varnish products. In the present case the affected person, although not actively engaged in handling tung oil, was present in the laboratory in which tung oil was being utilized in varnish making. The irritation appeared soon after this person was admitted to the laboratory and continued for many months before it was eventually terminated. During this time, however, tkpe irritation was most evident in the region of the groin and about the face and eyes, although on several oc-
casions i t covered the entire body. It was most apparent as a reddening of the skin, accompanied by violent itching and burning. On certain parts minute water blisters were often present. After a long period of ailment, it was suspected from daily observations that the source of the trouble lay in tung oil. By careful correlation it was found that the greatest activity followed the days on which closest contact was had with the vapors of heated tung oil. When contact with the oil’s vapors was avoided after a severe attack, the irritation invariably lessened in intensity but did not show immediate signs of complete disappearance; it even continued in a semimild manner for several months after the subject was removed from the tung laboratory. The variety of tung oil used a t that time was dark in color and was probably of Chinese origin. After all conceivable topical applications were found to be of no avail, relief was obtained in the following manner.
Treatment Since the irritation was evidently being caused by materials present in the vapors issuing from tung oil, it was thought possible that injection of such material into the body r i g h t prove
MAY, 1938
INDUSTRIAL AND ENGINEERING CHEMISTRY
beneficial. Thus, raw tung oil was heated in a distilling flask, and 2 to 3 per cent of oily distillate was collected before the main body of the oil gelled. This light colored distillate had an exceedingly pungent odor and was perceptibly irritating to the inucous membranes. (After standing in a tightly stoppered bottle for several months this material lost practically a11 of its original odor.) While still fresh the distillate was dissolved in specially purified olive oil, and dilute solutions of it were injected into the subject’s hip a t various intervals. Even a 1 per cent solution proved very painful when applied in this manner and was accompanied by a strong reaction. A tremendous increase in the dermatitic condition resulted, and the entire body assumed a reddish hue and burned and itched violently. After a few such injections of regularly increasing concentration, the irritation began to subside and after a few weeks had entirely disappeared. Thereafter the worker avoided, as far as possible, any contact with the vapors of heated tung oil. After about one year of freedom from any trace of this dermatitis, the subject found it necessary to remain for some time in close range of a vessel of heated tung oil. I n less than 12 hours after this exposure to the oil, the original dermatitis reappeared and covered most of the face and certain other parts of the body. It remained quite active for several days and then began to subside; after a week or ten days it had entirely disappeared unaided. Thus it was evident that the original hip injections had either begun to wear off or had caused only partial immunization. The author does not wish to imply, however, that the above method is the only or even the best treatment for an ailment of this sort. Although daily observations showed tung vapors to be the irritant in this case, ordinarily if the exact cause is not known or even suspected, the “patch test” diagnosis is possibly to be recommended. I n any case, however, diagnosis, and especially treatment, of an ailment of this sort should be carried out only under the supervision of a skilled dermatologist. Obviously each specific case requires individual consideration, depending upon the nature of the irritant, so that a treatment can be devised which will not be detrimental to the health of the patient. I n the present case the injection treatment proved successful. I n some instances, however, such a treatment could conceivably become dangerous if not carried on by a competent physician. The need for extreme caution in any event cannot be overemphasized.
Source of Irritation There seems to be considerable doubt as to the nature of the exact material responsible for the irritation, although this characteristic of the oil has been noted by other workers as well. For example, Gardner (7) calls attention to a dermatitic condition which resulted from exposure to heated tung oil but which was eventually “thrown off .” Lin (12) states that the oil from the tung shu nut is (‘very poisonous when fresh.” Schumann (15) likewise warns of its “exceedingly poisonous character.” Hertkorn (8) cites cases of its use in pharmaceutical preparations, as well as of severe abscesses and suppurations resulting therefrom. Similar observations have been reported by others (1-4, 13). Kronstein (10) noted that, when tung oil is exposed to heat for an undue time, “very essential changes will take place in the material which are indicated by the evolution of very pungent gases which act as irritants upon the eyes and the mucous membranes.” According to Fromefield (6) tung oil dermatitis does not appear to be uncommon among the native workers in China. He recalls that a simple native remedy for persons poisoned by the oil from the tung shu tree is to boil a quantity of pine shavings in water and bathe the poisoned parts repeatedly. On the other hand, Thomson (17) expresses the belief that
515
the irritant properties of tung oil are due to its adulteration with Chinese (or Japanese) lacquer oil, produced from the poisonous sumach (Rhus vernicifera) whose irritant properties are well known (6, 9,16, 23). Regardless of whether or not this is the case, a brief note concerning lacquer oil seems to be justified a t this point. The constituent responsible for the dermatitic properties of lacquer oil has been termed urushiol,^' an unsaturated dihydric phenol of the following composition: OH
I
()-OH
u
-Cii“~
This lacquer oil has been stated to be the most irritating oil known (21, ZZ), and its lacquer work has been known to cause severe irritation even after 1000 years (18, 19) (some persons contract dermatitis by passing near a lacquer tree). It must not, however, be confused with the widely used China wood oil (tung oil) produced by the Aleurites fordii and montana, species indigenous to South, Central, and West China. Perhaps the most familiar example of irritation from lacquer oil deals with numerous cases of dermatitis which accompanied the playing of mah-jongg (using imported counters) in this country in the early twenties (11, 24, 26). Thus it is evident that the identity of the agent directly responsible for tung oil dermatitis has not yet been revealed. Further, i t appears that tung oil does not stand alone in its role of irritant. Vokoun (20) reported the existence of hundreds of cases of dermatitis associated with the handling of linseed oil. Some mention has also been made of cottonseed dermatitis (14).
Acknowledgment Thanks are expressed for the sincere cooperation given by J . E. Kiley, dermatologist, of Montclair, N. J., under whose supervision the injection treatments were carried on.
Literature Cited Barry, T. R.,Chem. A g e (London), 15,490 (1926). Burnside, F’., Drugs, Oils h Paints, 39, 284 (1924). Chopp, C. L., Ibid., 32, 81 (1916). Fasig, E. W., P a i n t , Oil Chem. Rev., 73, 11 (1922). Fromefield, F., English Illust. Mag., 448, 199 (1913). Gardner, H. A,, Paint Mfrs. Assoc. U.S., Circ. 271, 17 (1926). Gardner. H. A., private communication. Hertkorn, J., Chem.-Ztg., 27, 635 (1903); Chem. Zentr., 1903, 11, 390. (9) Hixson, A. W., and Bee, Bai-Ziang, P a i n t , Oil Chem. Rev., 81, 15-21 (1926). (10) Kronstein, A., U. S. Patent 737,249 (Aug. 25, 1903). (11) Levin, 0 . L., J. Am. Med. Assoc., 82,No. 6, 465 (1924). (12) Lin, D. Y., Drugs, Oils h Paints, 35,292 (1920). (13) Mackay, R. C., Ibid., 32, 413 (1917); P a i n t , Oil Chem. Rev., 78. 8 (1924). (14) Nixon, J. A,,’ Bristol Medico-Chirurgical J. (London), 33, No. 128, 73 (1915). (15) Schumann, C. L., J. IND.ENG.CHEM.,8, 5 (1916). (16) Stevens, G. H.. “China Wood-Oil Formidars.” Irvinston, - 0.435. . N.J., pub. by G. H. Stevens, 1924. (17) Thomson, J. C., thesis, Columbia Univ., 1933. (18) Toyama, I., J. Cutaneous Diseases, 36, 157 (1918). (19) Toyama, I., and Kayaba, T., Jupan. Med. Lit.,2, 1 (1917). (20) Vokoun, F. J., J. Am. M e d . Assoc., 89, 20 (1927). (21) Walker, N., “Introduction to Dermatology,” p. 110, New York, W. Wood & Go., 1922. (22) White, R. P., “Occupational Affections of the Skin,” 2nd ed. p. 236, h‘ew York, P. B. Hoeber, 1920. (23) Bee, Zai-Ziang, thesis, Columbia Univ., 1926. (24) Zeisler, E. P., J. Am. M e d . Assoc., 82, 466 (1924). (25) Zwick, K. G., private communication. (1) (2) (3) (4) (5) (6) (7) (8)
RECEIVE December D 31, 1937.
