December, 1929
INDUSTRIAL AND ENGINEERIXG CHEXISTRY
This is shown diagrammatically in Figure 7. The liquid between two particles in a paste, as represented by liquid molecules (a), might thus be attracted by both solid surfaces. With a limited amount of liquid, the tendency will be to draw the particles closer together, and the stronger the attraction (or the higher the adhesion tension) the greater will be this tendency. It follows that the closer together the particles the smaller would be the amount of liquid which could be held in the paste. I n other words, the greater the adhesion tension of the liquid against the solid, the less will be the volume of liquid that will be required to “wet” the powder. This relationship was actually found in the experimental work. I n view of the foregoing discussions, it becomes evident that the amount of oil held by the powder may depend to quite an extent upon the precise method employed in bringing together the oil and the powder. Greatest variations are to be expected with liquids giving a large angle of contact with the solid. With such liquids much entrapped air may be held. It is believed that a fairly exact representation of the condition which may exist within a system of a powder wet by different liquids is given in Figure 8. Here the particles of powder are represented as spheres. The relation of volume of liquid to volume of entrapped air is shown by the black and white portions, respectively. At the left is represented a
1253
liquid having a large angle of contact, resulting in relatively small volume of liquid and large volume of air. The central portion of the diagram represents conditions when a zero contact angle is approached. With liquids which wet more completely, air would be displaced from the solid and would tend to escape from the mass. A liquid giving a high degree of wetting (high adhesion tension) would tend to displace the air completely. As the adhesion tension is further increased, the solid particles are drawn closer together, with the result that the relative amount of liquid held by the solid becomes less. If the above-expressed views are correct, it follows that the maximum of “liquid absorption” should be obtained with those liquids which give an intermediate degree of wetting against the solid. The most favorable condition for high oil absorption by the Gardner-Coleman method would be obtained with a liquid giving a zero contact angle with the solid, but having a low adhesion tension against the solid. Literature Cited Baldwin, IND.ENG.CHEM.,21, 326 (1929). Bartell and Osterhof, I b i d . , 19, 1277 (1927). Bartell and Osterhof, 2. physik. Chem., 190, 715 (1927). Bartell and Osterhof, Colloid Symposium Monograph, Vol. 5, p. 1 1 5 (1927). (5) Bartell and Smith, IND. END. CHEM.,21, 1102 (1929). (6) Gardner and Coleman, Paint Mfrs. Assocn. U. S., Tech. Circ. 86.
(1) (2) (3) (4)
New Solvents for the Active Principles of Pyrethrum’ W. A. Gersdorff and W. M. Davidson BUREAU OF CHEMISTRY AND SOILS, AND FOOD,DRUG,A N D INSECTICIDE ADMINISTRATION. U . S. DEPARTMENT OF AGRICIILTURE, WASHINGTON, D.
HE kerosene extract of pyrethrum (Chysanlhemum cineraria e folium, Trev.) now appearing
T
A number of solvents, some miscible with water and some immiscible, some flammable and some nonflammable, completely remove the active principle of pyrethrum for practical use against Myzus persicae Sulz. Many of these vehicles are suitable for application on plants as resistant as cabbage because they do not injure the foliage, whereas kerosene causes such severe injury that it is unsuitable. At 5 per cent concentrations all the extracts tested except xylene and amylene dichloride give effective control against Myzuspersicae Sulz, without injury to cabbage. -
on the market in large quantities possesses several characteristics which restrict its uses. Among these are combustibility, immiscibility with water, and injurious action on the foliage Qf plants. The investigathn here reported was conducted to find solvents that are free from these undesirable characteristics. Table I-Quantity
of Material Extracted f r o m Pyrethrum by Various Solvents BOILING POINT TOTAL MATERIAL EXTRACTED AT: SOLVENT Boiling temp. Room temp. Per cent Per cenf O c. Methyl alcohol 24.6 19.2 65 Ethyl alcohol (95 per cent) 22.1 18.4 7s 82 Isopropyl alcohol 14.7 10.2 9.0 118 Normal butyl alcohol 17.4 8.8 Secondary butyl alcohol 100 13.7 83 9.5 12.6 Tertiary butyl alcohol 6.9 80 Benzene 6.2 138- 139 6.9 Xylene 6.9 Carbon tetrachloride 77 6.3 5.3 8.1 Chloroform 7.1 61 7.2 84 Ethylene dichloride 6.6 145 17.9 Amylene dichloride 12.5 5.2 121 8.5 Tetrachloroethylene 126 9.7 Diethyl carbonate
1 Presented by W. A. Gersdorff and W. S. Ahbott before the Division of Agriculture and Food Chemistry at the 75th Meeting of the American Chemical Society, St. Louis, Mo., April 16 to 19, 1928. Revised manuscript received August 19, 1929.
c.
Procedure
About 50 pounds of finely ground pyrethrum were well! mixed. To test the thoroughness of the mixing, eight 2gram samples were taken at. different places for nitrogen determination. The percentages of nitrogen found--1.77, 1.71. 1.77. 1.77. 1.74. 1.77. 1.79; and ’1.77Lshowed that the supply was well mixed. Extractions were made a t room3 temperature and a t the boiling temperatures of the solvents. In each extraction a quarter of a pound (113 grams) of t h e pyrethrum was used and the resulting solution was made to. 1 liter. The apparatus for extraction a t room temperature consisted of percolators made of 2-inch glass tubing. Ten-inch (25.4-em.) lengths were drawn down a t one end to a diameter of ”8 inch (0.9 cm.). The constricted ends were loosely plugged with cotton, and the pyrethrum powder was lightly packed over it. The method of extracting a t room temperature was the ordinary method of percolating. Successive portions of the solvent were added until all soluble matter had been dissolved and washed out. A preliminary determination of the amount of residue in successive extractions showed that the color of the solution indicated very well the attainment of this object. For the extraction a t the boiling temperature of the solvent the apparatus used was of the Soxhlet extractor type, but so. modified as to allow the use of a quarter of a pound (113
INDUSTRIAL A N D ENGINEERING CHEMISTRY
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'Tal~le11-Results of Greenhouse T e s t s w i t h Various Solvents on Cabbages Infested w i t h M y z u s persfcae Sulz. CONCN. . INJURY BY APHIDS TO SOLVENT VOLUMEUSED APHIDS DEAD CABBAGE % No. No. % WATER AS DILUENT Moderate 34 179 60 Methyl alcohol None 0 - ._. 0 150 None 57 16 351 1004 Ethyl alcohol Severe 94 273 100 256 Isopropyl alcohol None 7 13 183 Severe 100 153 153 Normal butyl alcohol None 81 51 159 10 Moderate 99 166 168 100 Secondary butyl alcohol None 77 62 81 Moderate 95 127 134 Tertiary butyl alcohol None 10 7 150 10 9 1 1>ER CENT ETHYL ALCOHOL AS DILUENT None 75 228 171 10 Benzene None 5s 64 111 5 Very severe 136 100 10 136 Xylene Moderate 87 108 124 5 Slight 83 157 190 10 Carbon tetrachloride Slight 50 49 98 5 None 24 52 216 10 Chloroform None 41 37 112 5 None 76 85 112 10 Ethylene dichloride None 54 52 5 96 Severe 76 104 136 10 Amylene dichloride Severe 97 115 111 5 Severe 93 156 10 168 T drachloroethylene None 61 114 70 5 Moderate 44 10 147 64 IAethyl carbonate Slight 75 114 85 5 0 The commercial 95 per cent ethyl alcohol was used without dilution.
f 'E
I
Vol. 21, No. 12
grams) of pyrethrum and 800 cc. of solvent in a single extraction and the recovery of the entire residue. After extraction each solution was made to 1 liter with the proper solvent and the amount of material extracted was determined by evaporating an aliquot on the steam bath. Table I shows the solvents used and the quantity of material extracted by each solvent a t room temperature and a t the boiling point of the solvent. The pyrethrum, after both hot and cold extraction with the various solvents, was tested a t the Insecticide Testing Laboratory of the Food, Drug, and Insecticide Administration a t Silver Spring, Md. In all cases it was found to be entirely inert against the aphid M u m s persicne Sulz., thus showing that all the solvents used had removed or destroyed the insecticidal principle effective against this insect. The differences in quantity of extracted material, therefore, apparently are due to inactive material. McDonnell, Roark, LaForge, and Keenan (1)had previously found that chloroform, carbon tetrachloride, methyl alcohol, ethyl alcohol, and benzene remove the insecticidal principle. These solvents were included in the group used in the present study for purposes of comparison.
T a b l e 111-Greenhouse T e s t s with Various P y r e t h r u m E x t r a c t s on Cabbages Infested w i t h M y z u s persicae Sulz. CONCENCONCENTRATION
TRATION OF
OF
SPRAY
INJURY
EXTRACTANT AND TEMPERA- BY APHIDS TO TURE OF EXTRACTION^ VOLUMEUSED APHIDS DSAD CABBAGE NO. NO. 70 %
1' ;!
WATER AS DILUENT None 173 173 100 None 104 io4 100 170 R.X. None 167 (14 None 117 118 Methyl alcohol, R. T. None 122 100 122 None 130 100 130 None 99 61 62 1 3 None 131 103 1 2 79 None 99 192 25 193 None 122 100 122 None 99 170 171 None 100 114 114 None 96 Methyl alcohol, B. T. 151 15V None 100 176 176 None 92 86 93 None 88 84 95 N' one 212 212 100 None 154 155 99 None 92 188 205 None 99 134 135 iione 89 124 139 None 89 103 116 Ethyl alcohol, I R. T. None 91 96 105 None 87 99 114 None 82 125 153 None 83 79 95 Xone 77 66 86 None 99 190 191 None 98 190 19 3 Kone 97 180 186 None 99 136 137 None 91 114 125 None 97 98 101 Ethyl alcohol, B. T. None 93 137 148 None 96 106 110 None 96 118 123 None 77 65 84 None 72 62 86 None 99 190 192 None 99 153 154 None 99 112 113 Isopropyl alcohol, R. T. None 98 149 152 None 96 103 107 None 99 168 170 None 99 113 114 None 99 152 Isopropyl alcohol, B. T. 154 None 98 166 169 None 95 99 104 Slight 100 172 172 ' 25 None 100 170 170 10 Slight 97 142 146 10 None 97 197 204 . 5 Normal butyl alcohol, R. T. None 94 122 130 5 None 90 139 155 3 None 79 149 188 3 Slight 99 ' 25 104 103 None 98 144 147 10 None 9 s 124 127 Normal butyl alcohol, B. T. 1 10 None 99 137 138 None 97 228 234 0 R.T. signifies room temperature and B. T. boiling temperature. b Although commercial 95 per cent ethyl alcohol was used in making this pyrethrum extract, denatured alcohol could be used without the,extract showing any significant dillerence in toxicity a t the same concentratlons.
i i: ii:
__
SPRAY INJURY APHIDS TO VOLUME USED APHIDS DEAD CABBAGE % No. No. %
EXTRACTANT AND TEMPERA- BY TURE OF
EXTRACTION"
WATER AS DILUENT (CONT.)
25 10 Secondary R. T.
Secondary B. T.
butyl
butyl
alcohol.
alcohol,
Tertiary butyl alcohol, R. T.
Tertiary butyl alcohol, B. T.
10
3 3 25 10 10 5 5 25 10 10 5 5 25 10 10 10 5
5 5
197 128 154 132 158 174 135 117 112 148 138 180 136 192 178 155 193 162 162 139 215 145 140 180
197 128 153 131 152 168 131 116
111
139 136 168 135 191 173
150
185 162 162 138 208 142 132 166
100 100 99 99 96 97 97 99 99 94 99 93 99 99 97 97 96 100 100 99 97 98 94 92
None None None None None None None None None None None None None None None None None None None None None None None None
)ER CENT ETHYL ALCOHOL A S DILUENT
Benzene, R. T. Benzene, B. T. Xylene, R. T. Xylene, B.
T.
Carbon tetrachloride, R. T. Carbon tetrachloride, B.
T.
Chloroform, R. T. Chloroform, B.
T.
Ethylene dichloride, R.
T.
Ethylene dichloride, B. T. Amylene dichloride, R.
T.
Amylene dichloride, B. T. Tetrachloroethylene, R. T. Tetrachloroethylene, B. T. Diethyl carbonate, R. T. Diethyl carbonate, B.
T.
10 5 3 10 5 3 10 5 10 5 25 10 5 25 10 5 20 10 5 20 10 5 10
5 10 5 10 5 10 5 5
156 134 265 284
154
236 124 132 119 147 120 145 142 125 196 235 156 171 216 161 277 261 110 117 172 188 150 223 150 249 118 110 219 122 189 113 177
152 133 208 284 150 202
124 132 119 147 120 145 136 125 192 234 152 171 207 160 277 258 103 116 172 187 150 223 150 248 118 109 217 122 189 113 177
97 99 78 100 97 86 100 100 100 100 100 100 96 100 98 99 97 100 96 99 100 99 94 99 100 99 100 100 100 99
100 99 99 100 100 100 100
Slight Slight None None None None Very sever Moderate Very sever Severe Moderate Moderate None Slight None None None Slight None None None None None Slight Moderate Slight Very severe Severe Very severe Severe Slight Slight Slight Moderate None Severe Moderate
December, 1929
INDUSTRIAL AND ENGINEERING CHEMISTRY
The solvents and the extracts were tested against aphids (Mytus persicae Sulz.) on cabbages. Potted cabbage seedlings in the greenhouse harboring the aphids were sprayed from an atomizer of about 40 cc. capacity. The aim was to cover the leaf and stalk, as well as the surface of the soil. The spray material was usually a clear solution, but in some cases, those of the more difficultly soluble extractants, it was shaken up into an emulsion, without, however, the addition of an emulsifier, and applied as such. The number of aphids to each test ranged usually from 100 to 250, infesting two or three plants. Observations were made 24 hours later to determine the mortality of aphids. Among the aphids counted as dead are included the few insects repelled from the plants in the manner peculiar to pyrethrum. This number varied slightly, not with the extracts, but with the concentrations. A second examination to determine injury to the cabbage plant was made five days after the spraying. This injury is classed as slight, moderate, severe, or very severe. Slight injury is either faint spotting on the leaf or localized curling of the leaf edge. Moderate injury is more pronounced discoloration, often extending through the leaf tissue to form window-like spots. Severe injury is the crumpling or discoloration of whole leaves and wilting of stalks. Very severe injury is destruction of the plant. Plants injured to x slight or moderate extent made normal subsequent growth. Those severely injured made subnormal subsequent growth and were feeble. Where injury to the plants was severe enough to cause aphids to leave from lack of food it was difficult to determine the actual mortality. This was more pronounced when the injury appeared immediately after the spraying. The results of these tests are shown in Tables I1 and 111.
1253 Results
Methyl, ethyl isopropyl, normal butyl, secondary butyl, and tertiary butyl alcohols, as well as benzene, xylene, carbon tetrachloride, chloroform, ethylene dichloride, amylene dichloride, tetrachloroethylene, and diethyl carbonate, completely remove from pyrethrum the insecticidal principles effective against the aphid M y - u s persicae Sulz. Kormal and secondary butyl alcohols a t 10 per cent concentrations in water and benzene, carbon tetrachloride, ethylene dichloride, tetrachloroethylene, and diethyl carbonate a t 5 per cent concentrations in ethyl alcohol kill 50 per cent or more of these aphids without injury to cabbage. At 5 per cent concentrations all the extracts except xylene and amylene dichloride give effective control against Mytus persicae Sulz. without injury to cabbage. Normal and secondary butyl alcohols show markedly greater toxicity to these aphids than tertiary butyl and isopropyl alcohols, which, in turn, show markedly greater toxicity than methyl and ethyl alcohols. Roark and Cotton (2) found the butyl alcohols and isopropyl alcohol to be more toxic than methyl and ethyl alcohols, in the vapor phase, to rice weevils. If cost is taken into account, denatured ethyl alcohol appears to be the best of the solvents tried for extracting pyrethrum when the extract is to be diluted with water for application upon plants. There is no advantage in the extraction of pyrethrum with these solvents a t their boiling point temperatures over that a t room temperature. Literature Cited (1) McDonnell, Roark, LaForge, and Keenan, U S Dept Agr.. Bull 824 . (1926) (2) Roark and Cotton, U S Dept Agr , Tech Bull. 162 (In press).
Ratio of Fluorine to Phosphoric Acid in Phosphate Rock' D. S. Reynolds, K. D. Jacob, and W. L. Hill FERTILIZER AHD FIXEDNITROGEN INVESTIGATIONS, BUREAUOF CHEMISTRY AND SOILS,WASHINGTON, D. C.
I
N A recent paper Jacob and Reynolds (9) have s h o r n that
the commercial types of phosphate rock produced in the United States usually contain about 3.2 to 4 per cent fluorine. Results given by these writers indicate that an approximately constant ratio may exist between the fluorine and phosphoric acid in most of the domestic types of phosphate rock, the ratio, however, apparently varying somewhat with each type of rock. If a more or less definite ratio exists between the fluorine and phosphoric acid in a given type of phosphate rock, its determination will have a practical application in that it will permit the calculation of the approximate fluorine content of a sample of rock from its phosphoric acid content. The determination of fluorine requires special reagents and apparatus which are not always readily available, while the accurate determination of phosphoric acid is a comparatively simple operation requiring no special equipment. A careful investigation of the relation between the content of fluorine and of phosphoric acid would undoubtedly assist in deciding many uncertain points relating to the chemical composition, constitution, and origin of phosphate rock. Received August 9, 1929. Presented before the Division of Fertilizer Chemistry at the 78th Meeting of the American Chemical Society, Minneapolis, Minn., September 9 to 13, 1929. I
The present paper gives the results of a study of the fluorine-phosphoric acid ratios in the commercial types of phosphate rock now mined in the United States. Types of Phosphate Rock in United States
I n the order of their present commercial importance, the domestic types of phosphate rock are: Florida land-pebble (13, 15); Tennessee brown-rock (15); Florida hard-rock (13, 1 5 ) ; Tennessee blue-rock ( 1 5 ) ; the phosphates of Idaho, Montana, Utah, and Wyoming (11, 15); the soft and waste-pond phosphates of Florida (IS); and South Carolina phosphate (15). The general characteristics of the phosphates and the nature and extent of the deposits are discussed in the publications cited.2 The South Carolina deposits were formerly an important source of phosphate rock in the United States. Exploitatios of these deposits ceased, however, several years ago, owing t o the low grade of the rock and the cost of mining in competition with Florida land-pebble phosphate. As the name implies, Florida soft phosphate is a soft, clay-
* Statistics relating to the production of the different types of phosphate rock are given in "Mineral Resources of the United States," publishes annually by the U. S. Bureau of Mines, and in "The Mineral Industry," published annually by the McGraw-Hill Book Co.
