INDUSTRIAL A N D ENGINEERING CHEiWISTRY
1172
hydrous soaps. Both the pure and commercial grades are unstable on heating and lose their volatile base, behaving in this respect like the ammonium soaps. TAELE 11-COMMERCIALNICOTINESOAPS OLEATE PER CENT
COCONUT OIL-FATTYACID COMPOUND P E R CENT
Comgosition 23.5 41.2
Nicotine 26.3 F a t t y acid 34.2 Total active ingredients 60.5 (i. e., nicotine soa ) 64.7 Inert ingredients, ckefly 39.5 35.3 water Color Very dark brown (like Dark brown caramel) Sirupy liquid, solidifyConsistency Soft paste ing t o stiff paste a t about 10' C.
Solubilities
No. 30 denatured alcohol Miscible and soluble to Miscible and soluble to turbid solution Virtually insoluble Miscible 1:1, only partly soluble in excess Virtually insoluble Miscible and soluble in all proportions t o clear solution Miscible and soluble t o turbid solution
Ethyl ether Petroleum ether Carbon tetrachloride Glvcerol Water
clear solution Virtually insoluble Virtually insoluble
Virtually insoluble Miscible and soluble in all proportions t o clear solution Miscible and soluble to clear solution
COMPARISON OF SOAP-LIKE PROPERTIES OF PURE AND COMMERCIAL SOAPSOLUTIONS Comparisons were made of the soap-like properties of the pure and commercial nicotine soaps in solution, all the tests being made a t 20' C. The results are shown in Tables I11 and IV. TABLE 111-SOAP-LIKE
PURE NICOTINE SOAPS Pure potash coconut oil soap; anhyPURE ANHYDROUS NICOTINE SOAPS OF drous and glycCoconut oil Castor oil eroi free (for Oleic acid fatty acids fatty acids comparison) cc cc. cc cc.
.
(1) Distilled water 0.2% solution 0.5% solution
PROPERTIES OF
Lathering test
185 310
1% solution Not tested (2)H & d water (hardness 300 p. P. m. CaCOa) 0 0,5'% solution 25 1% solution
1% solution in
distilled water
153
415 630
Not tested
85 405 Drop number 201
.
0 10 100
Not tested
0 60
Not tested Not tested
232
500 950
430
LATHERING OR FOAMING PowER-This test is a measure of the surface tension of a soap solution versus air. A known weight of soap dissolved in 100 cc. of either distilled or hard water of known hardness is pipetted into a 1-liter, glass-stoppered cylinder, which is shaken for 1 minute in a mechanical shaking device, and the net volume of lather remaining after 1 minute subsidence is recorded. DROPNUMBER-This test is a measure of the interfacial surface tension between an unsaponifiable oil and the soap solution. The larger the drop number, the lower is the interfacial surface tension. A large drop number is usually considered indicative of good wetting and spreading properties. The apparatus used consists of a special brass stalagmometer pipet of about 5-cc. capacity and having a capillary opening 0.1 mm. in diameter. The pipet is filled to a definite level with a solution of the soap t o be tested and clamped in position with the capillary opening 10 cm. below the surface of 650 cc. of liquid petrolatum-i. e., medicinal mineral oil-in an 800-cc., tall beaker. The soap solution is allowed to flow into the oil and the number of drops formed is recorded. SURFACE TENSION BY DU NOUY SURFACE TENSIMETER-This tensimeter measures the force in dynes required to detach a platinum loop of 4-cm. circumference from the surface of a solution. The surface tension of pure distilled water as measured by this instrument is 77.7 dynes per centimeter a t 20" C., and the addition of small amounts of soap markedly lowers this value. SPREADING TEST(applied only to the 1:500 dilutions of the commercial nicotine soaps, this dilution representing a suitable concentration of nicotine for use as a contact insecticide)-A
Vol. 16, No. 11
piece of sheet metal was coated with a uniform thin layer of paraffin. From a capillary pipet 0.3 cc. of the soap solution was allowed to flow onto the paraffined surface, forming a single large drop. The diameter of this drop and the area to which it could be mechanically spread as a continuous film was measured. TABLE Iv-SOME
PROPERTIES OF COMMERCIAL NICOTINEOLEATE AND NICOTINE-COCONUT OIL-FATTY ACID COMPOUND IN SOLUTION COCONUT OIL-FATTY OLEATE ACID COMPOUND Concentration of soap solution in distilled water, except 1 part in 500 1 part in 500 as otherwise noted Concentration of nicotine in final solution 0.0470% 0.0528%
Droa number 82 98 Volume of drop Diameter of drop Area on which drop could be spread
Spreading test 0.3 cc. 1.1 cm.
85 160
.
70 sq. cm. Surface tension by Du Nouy surface tensimeter Dynes per cm. a t 20' C. 39.6 (Distilled water = 77.7 dynes) Lathering test Distilled (hardness Hard water 300 Distilled Solution
0.2% 0.5% 1.0%
water cc.
140 285 245
p. p. m. CaCOs) cc
.
.. ..
20
0.3 cc, 1.7 cm. 115 sq. cm. 30.0 (hardness 300 Hard water
water cc
p. p. m. CaCOs) cc.
225 390 735
230
.
..0
The results in Tables I11 and I V show a definite superiority of the nicotine-coconut oil-fatty acid compound over the oleate in both the pure and commerical grades, even in distilled water. There is a still more marked difference in favor of the coconut oil-fatty acid compound in hard water, because coconut oil soaps react much less readily than do the soaps of oleic acid with the calcium and magnesium compounds of hard water to form insoluble soaps. d
EFFECT ON INSECTS A survey to determine the suitable concentration was first made. Directions for the use of various preparations containing nicotine recommend quite generally a concentration equivalent to approximately 0.05 per cent nicotine in the spraying solution. The concentration chosen for tests on the commercial nicotine soaps, both oleate and the coconut oil-fatty acid compound, was 1 part in 500, using soft water. The nicotine soap solutions were compared for wetting power and effectiveness on the only available insects, as follows: green apple aphis (Aphis pomi) on young apple trees and current bushes; wooly aphis (Erisoma lanigera) on twigs of apple trees; and cabbage aphis (Aphis brassicae) on turnips and cauliflower. Both nicotine soap solutions (whose concentration of nicotine was practically 0.05 per cent) were found t o be very effective in kiIling the aphis, provided the spraying was done with sufficient thoroughness to reach and wet all the insects on the affected plants, The superior wetting and spreading power of the nicotine-coconut oil-fatty acid compound was particularly noticeable on the waxy leaves of the turnips and cauliflower, and on the downy young leaves of the apple. To secure comparable wetting with the nicotine oleate, considerably more time, effort,and solution were necessary.
Brined Vegetables Studied The Bureau of Home Economics of the United States Department of Agriculture has recently cooperated with the Bureau of Chemistry in tests on the utilization of brined vegetables. These tests showed that green tomatoes, and green peppers particularly, could be kept successfully in brine for as long as six months and then used in a number of ways. Mock mince-meat, Bordeaux sauce, and pickle were all made from the green tomatoes, and the peppers were satisfactory for stuffing as well as for seasoning various dishes.
