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I N D U S T R I A L A N D ENGINEERING CHEMISTRY
however, when the oil was thoroughly refined before making the ethyl esters. A run was also made with a crude H . wightiana oil of 9.5 per cent acidity, hydnocarpic acid of freezing point 53.3O C. being obtained, by three distillations. It is therefore concluded that chaulmoogra oil is not suitable for the economical production of hydnocarpic acid. Analysis of Minor Oils
In continuation of the analysis of various chaulmoogragroup oils begun in the earlier paper12 examinations were made of the seeds of Asteriastigma macrocarpa (from the Conservator of Forests, Travancore, India), Hydnocarpus caulijora (from the Provincial Treasurer, Cotobato, P. I.), Hydnocarpus ovoidea (from W. A. V. Wiren, Catarman, Samar, P. I.), and Hydnocarpus woodii (from D. D. Wood, Conservator of Forests, British North Borneo). Table I shows the general characteristics of the oils obtained by extraction of these seeds. The Asteriastigma seeds are very similar in appearance to those of Hydnocarpus alcalae, and the high freezing point of the fatty acids of the former approaches that of the latter (55" C.). Fractionation of the ethyl esters gave further evidence of the similarity of these two oils, in that the first fraction from each gives chaulmoogric acid instead of hydnocarpic, on hydrolysis and recrystallization. The Asteriastigma oil is inferior to H . alcalae oil in rotatory power, however.
Vol. 19, No. 8
The seeds and oil of Hydnocarpus caulij7ora are very similar to those of H . hutchinsonii. The very low optical rotation of H . oviodea oil precludes its classification, chemically, as a chaulmoogra-group oil. The data for H . woodii are somewhat different from those reported in the earlier paper for a small and rather old sample. On fractionating the ethyl esters from this oil it was found to be very similar to the oil of T. kurzii. T a b l e I-Characteristics Asteriasligma OIL macrocarpa Sp. gr., 3Oo/3O0 C. 0.936 n3: 1.4709 Freezing point, O C. 30 Rotation 100 mm., 36 Iodine number, Hanus 87.6, Saponification number 201 Acidity, as per cent oleic 8.2 Fatty acids: Freezing point, C. 50 39
of S o m e Minor Oils HydnoHydnccarpus carpus cauliflora ovoidea 0.946 0.915 1.4732 1.4637 25 25 42 1 84 47 201 215 0.8 5.8 42 38
40 0.7
Hydno: carpus woodii 0.949 1.4755 21 49 96 206 2.;
44 55
A sample of seeds obtained from a Calcutta firm as Hydnocarpus Castanea was examined, and the ethyl esters from it were fractionated. Data on this oil are not included in the table because the writers were not able positively to identify it botanically and because the oil was found indistinguishable chemically from that of T. kurzii.
Repellents for Blowflies' By R. C. Roark,*D. C. Parman, F. C. Bishopp, and E. W. Laakes BUREAUOF C H E ~ S T RAND Y BUREAUOF ENTOMOLOGY, WASHINGTON, D. C.
B
LOWFLIES are true flies that deposit their eggs or larvae on meat or in wounds on living animals or man. The larvae feed on the tissues of their host and usually cause death within a few days unless remedial measures are taken. There are many genera of blowflies, such as CaZZiphora, Lucilia, Sarcophaga, Cochliomyia, etc. One species of the lastnamed genus, C. macellaria Fab., is known in the United States as the screw-worm fly, and is estimated to cause an annual loss of at least $4,000,000 to the livestock owners in the southwestern states. In Australia and other wool-producing countries great loss among sheep is caused by Lucilia and Calliphora. The study of materials which may be used to kill blowfly maggots in wounds on animals, or to repel the flies, or to prevent their ovipositing in the wounds, is therefore one of great economic importance. Previous Work
Chloroform has been extensively used to kill maggots in wounds, but benzene has been found by Parman4to be more suitable and is now generally used in this country. For use as a repellent, nearly every material with a strong or disagreeable odor has been suggested at one time or another. Such materials as pyridine, fish oil, bone oil, and various essential oils have been proposed for this use by many authors in the agricultural literature. Proprietary preparations sold Part of paper presented by Mr. Roark before the Division of Agricultural and Food Chemistry a t the 73rd Meeting of the American Chemical Society, Richmond, Va., April 11 to 16, 1927. Insecticide and Fungicide Laboratory, Miscellaneous Division, Bureau of Chemistry. a Investigations of Insects Affecting the Health of Animals, Bureau of Entomology. 4 J. Agr. Research, 51, 885 (1925). 1
*
as screw-worm fly repellents usually contain crude carbolic acid, which is effective in keeping the flies away from wounds on which it is applied but the lower phenols are very toxic to cattle and other animals, and death of the host often results from the use of these preparations. Investigations conducted by the Bureaus of Entomology and Chemistry N u m b e r of Screw-Worm Flies C. macellaria Fab. Observed Visiting Fresh Beef Liver Treated w i t h v a r i o u s R e p e l l e n t s bornpared w i t h t h e N u m b e r Observed Visiting U n t r e a t e d Fresh Beef Liver (Figures are totals of several tests made at different times.) REPELLENT APPLIED~ DILUTED U N D I L u TE D PerPerNumber centage Number centage ratio ratio ratio ratio Powders: 3:324 1 1 :966 0.1 Copper carbonate 50 :862 6 Pyrethrum powder 14:231 D 71:1502 9:87 10 Powdered fresh cloves 76:1116 7 37:319 12 Iodoform 20 1:366 0.3 553276 Pinene hydrochloride 57 :260 0:770 0 22 Chloroacetophenone 15: 154 10 145:329 44 Hexachloroethane 53:199 27 5 5 : 101 54 Black pepper 212:929 23 133:232 57 Naphthalene 5 30:634 216:350 62 Derris powder Liquids: Wood naphtha Pine oil No. 4 Clove oil Turnentine. crude Chloropicrin Pine tar oil (sp. gr. 1.065) Pine tar Cade -~~~oil ~~. Ceylon citronella oil Star anise oil Pyridine Guaiacol American pennyroyal oil &Naphthyl, ethyl etherb Bergamot oil ~
26:296
240: 1635 422 : 1599
783286 599:1822 553: 1568 59: 160 519: 1366 259:455 787: 1366 192:312 841 : 1366 101: 160 1066: 1366 565:293
9 15
26
26 33 35 37 38 57 58 62 62 63 78 193
a Materials are arramed in the order of decreasina effectiveness as repellents when diluted. b Impure material which was liquid at the temperature of the tests.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
August, 1927
of the United States Department of Agriculture6have resulted in the discovery of several promising screw-worm fly repellents. One of these, pine-tar oil-obtained by the destructive distillation of the wood of the long-leaf pine, Pinus palusfris L.-is recommended as the most suitable for application upon wounds on animals on account of its cheapness, availability, non-toxicity, and adhesiveness, and is now being used on an extensive scale by ranchmen in Texas and other southwestern states. Experimental
During 1926 additional tests were made with the most promising repellents found up to that time. This work was carried on a t Uvalde and Dallas, Texas, where screw-worm flies are abundant. In order to test the strong repellents under as severe conditions as possible, they n-ere diluted, the powders with kaolin and the liquids with medicinal mineral oil, in the ratio of 9 parts diluent to 1 part repellent. The procedure of testing was the same as that previously described; that is, 4-ounce (113-gram) cubes of fresh beef liver, over the surface of which the repellent mixtures were smeared, were exposed from 2 to 5 days in pint Mason jars in an open shed where flies were abundant. The quantity of repellent mixture applied to each bait was 5 cc. for the liquids, or 5 grams for the solids. Untreated meat was exposed a t the same time, and the efficacy of the repellent is estimated by comparing the number of flies visiting the treated jar with the adjacent untreated or check jar. A percentage ratio of 100 indicates no repellent or attractant action; one 6
J . Econ. EntomoL., 16, 222 (1923); 18, 776 (1925); 19, 536 (1926);
U.S. D c p t . Agv., Bull. 1472 (March, 1927).
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of 0 represents perfect repellent action, while a percentage ratio of over 100 indicates that the material increased the attractiveness of meat to blowflies. A few of the more significant results are shown in the accompanying table. It is of interest to note that strongly odorous materials, especially the essential oils, which are quite effective in repelling screw-worm flies from meat when applied undiluted, lose nearly all their efficacy or may become actually attractive-. g., bergamot oil-when diluted 1 to 9 with an inert vehicle; whereas copper carbonate, which is entirely inodorous is nearly as effective in 10 per cent strength as when applied undiluted. Conclusion
These results, together with other observations, have led to the belief that the most effective blowfly repellents are not necessarily highly odorous materials, such as essential oils, or even highly irritating materials, such as chloropicrin and other “tear gases,” but are materials which can absorb, adsorb, or inhibit the formation of the volatile compounds evolved by decomposing meat which attract the flies to the meat. I n addition to various copper compounds, such strong antiseptics as mercuric chloride, potassium permanganate, sodium salicylate, etc., when applied to meat render it almost entirely non-attractive to blowflies. Tests are now being conducted to determine the practicability as blowfly repellents of copper carbonate and certain other powders when applied upon the wounds of animals under outdoor conditions.
Effect of pH on Adsorption by Carbons’ By S. M . Hauge2 and J. J. Willaman Dlvrsrow
08
AGRICULTURAL BIOCHEMISTRY, UNIVERSITY O F MINNESOTA, ST. PAUL, MINN.
Because of the great discrepancies in the results of various investigators, it has been apparent for some time that some factors in the evaluation of decolorizing carbons are not under control. The present writers have undertaken to show the effect of pH on adsorption by carbons. Data are presented which indicate that the more acid a solution is the greater is the adsorption of caramel and of benzoazurin, both of which are negatively charged colloids, while alkalinity favors adsorption of electropositive substances, such as methylene blue. The adsorption of amphoteric substances, such as proteins, is at a maxim u m in the general region of the isoelectric point of the protein, and is at decided minima in extremes of acidity
and alkalinity. Adsorption of dextrose, a non-electrolyte, is not affected by pH. In the application of carbons to specific requirements as encountered in industries, three factors should be considered-the electrical properties of the substances to be adsorbed, the electrical properties of the available carbons, and the permissible pH of the solutions used. Information concerning these properties should act as a guide in the choice of the carbon best adapted to the specific need, as well as the optimum conditions for adsorption efficiency. Thus, carbons may be prepared for specific requirements.
... ...... HE well-known property possessed by carbons of alkali-metal ions, according to investigations of Rona and removing coloring materials and other substances myself, and glycocol, according to Abderhalden and Fodor.” from solutions is commonly called adsorption. This Much of the research of recent years has been directed phenomenon is not a characteristic of all carbons to the same toward the production of highly active carbons, increasing degree, nor is it limited to any specific type of substances. the activity of carbons, and the reactivation of carbons. Both organic and inorganic substances, colloids and crystal- As a result several highly active decolorizing carbons have loids, substances which reduce surface tension and others appeared on the market in response to the demand of inwhich do not, are known to be adsorbed. M i c h a e l i ~ ~ ~dustries ~* requiring very efficient carbons. During some writes: “There are only two exceptions known hitherto preliminary work in 1922 on the production of active carbons, which are not a t all adsorbed by charcoal: the sulfates of very irregular and inconsistent results were obtained in 1 Received March 21, 1927. Published with approval of the Director attempting to evaluate these carbons. Some factor was as Paper N o . 689, Journal Series of the Minnesota Agricultural Experiment apparently not under control, and it was soon evident that Station. Abridged from a doctor’s thesis submitted by the senior author t o at least one important factor was the pH of the medium in the University of Minnesota. which the carbon was acting. Therefore, the series of ex2 N o w a t the Purdue University Agricultural Experiment Station, * Numbers in text refer t o the bibliography at end of article. periments reported herein was begun.
T
