T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y TABLE Va-PERCENTAGE
Water Brand M a y D a y ....... 73.92 Greenwood.. .... 77.49 81.37 Polk’s Best.
Ether extract 0.47 0.49 0.45
May Day.. . . . . . . . . Greenwood, . . . . . . . . Polk’s Best. . . . . . . . .
1.83 2.34 2.00
.....
Crude fiber 1.85 1.78 1.86
7.15 8.31 10.25
Proteid N X 6.25 5.61 4.73 4.22
21.74 21.01 22.31
DRAINED PEAS BASED ON ORIGINAL BASIS Crude Total ash Salt starch Sugar 0.99 14.06 0.39 0.89 1.28 10.17 0.74 1.31 0.89 7.97 0.41 1.56
C O M P O S I n O N OF
WATER-QREBBASIS 53.57 1.55 3.14 3.54 5.55 44.12 2.55 8.92 41.05
3.85 5.78 4.98
313
BRAND
Salt-free ash 0.60 0.55 0.47
.
2.30 2.41 2.43
CaO 0.059 0.058 0.043
MgO 0.040 0.033 0.039
0.179 0.157 0.146
0.25 0.27 0.23
0.158 0.151 0.203
0.694 0.677 0.761
P20r
T A B LVbPERCENTAGE ~ CoMPosInos OF CANNEDPEASBASED ON BRAND Original basis
Water free basis
r
Brand May Day... . . . . . . . . . . . . Greenwood . . . . . . . . . . . . . . . Polk’s Best. . . . . . . . . . . . . . .
Water 81.28 83.70 83.91
Proteid N X 6.25 4.17 3.37 3.27
Crude starch 9.42 6.60 5.35
Proteid Sugar 1.00
Salt 0.47
PzOj 0.139
1.71
0.43
0.125
..
..
There are t w o points t h a t lead us t o believe this is not t h e case. F i r s t , t h e liquor of t h e sample 7249 B is abnormally high in sugar, b u t t h e drained peas of this can show only a normal a m o u n t of sugar. Secondly t h e Polk’s Best B r a n d would before processing have the highest water content a n d would absorb a smaller a m o u n t of liquor upon processing. Therefore, unless selective absorption comes into play, t h e conditions cannot be laid t o the composition of t h e liquor. T h e question is one open for study. T h e salt-free ash is slightly higher in t h e youngest pea. Upon comparing t h e analysis of t h e sample of “Soaked P e a s ” with t h e above averages, it is found t h a t it agrees quite closely with t h e M a y Day grade. T h e reason for this is quite a p p a r e n t for as far as m a t u r i t y is concerned these grades lie very close together. Table VI shows t h e maximum salt-free ash content of 2.66 per cent a n d t h e minimum of z . o j per cent with a n average of 2 . 3 8 per cent. T h e alkalinity of t h e ash varies from 2 . j t o 2.1 cc. N / r o HC1 per gram TABLE VI-ASH
OF THE DRAINEDPEAS
Percentage composition of ash Salt-free ash Sample Water-free basis 7246 B . . . . . . . 2 . 4 9 7247 B . . . . . . . 2.36 7248 B . . . . . . . 2.05 7252 B . . . . . . . 2.47 7253 B . . . . . . . 2 . 6 6 7254 B . . . . . . . 2 . 0 9 7249 B... . . . . 2 . 2 8 7250 B . . . . . . . 2 . 3 4 7251 B . . . . . . . 2 . 5 3 7255 B . . . . . . . 2 . 5 6 7256 B.. . . . . . 2 . 3 9 Maximum.. . . 2 . 6 6 Minimum. . . . 2 . 0 5 Average., . , , , 2.38 (a)Cc. “10
Alk. of ash ( a ) 2.1 2.4 2.3 2.2 2.2 2.2 2.3 2.5 2.5
..
2.4 2.5 2.1 2.3
Pros 29.3 30.1 31.1 29.0 25.3 30.5 29.2 31.5 31.0 33.4 31.6 33.4 25.3 30.2
CaO 5.7 9.4 17.1 8.5 9.9 15.4 8.5 10.7 11.6 8.1 8.8 17.1 5.7 10.0
MgO 5.4 5.9 9.6 6.3 4.0 8.7 9.8 7.5 7.3 8.6 6.5 9.8 4.0 7.2
HC1 per gram water-free sample.
d r y sample. T h e phosphoric acid remains fairly constant averaging 2 5 . 3 per cent of t h e total ash. T h e CaO varies from j . 7 per cent t o three times t h a t a m o u n t . T h e MgO ranges from 4.0 per cent t o 9.8 per cent of t h e total ash. There seems t o be n o relation between t h e ash or a n y o€ its constituents a n d t h e m a t u r i t y of t h e pea.
...
N X 6.25
22.2 24.4 23.49
Crude starch 50.3 41.87 36.32
Sugar 5.27
Salt 2.52
...
..
10.67
2.41
PlOl 0.739 .
I
.
0.787
SUM M A R Y
T h e investigation has shown t h a t in a pack of peas p u t u p b y a single concern where t h e conditions are as nearly uniform as i t is possible t o make t h e m in factory work, great variations of results in individual samples are found. A large number of samples are desirable for conclusive results. There is considerable variation in t h e proportion of liquor a n d peas in t h e different grades of t h e product. T h e composition of t h e liquor of the canned pea is largely determined b y t h e blanching a n d processing, a n d a s t h e more m a t u r e peas require a longer period, we may expect t o find this grade with turbid liquors of high starch a n d proteid content. T h e young i m m a t u r e dried peas contain 18 per cent more water t h a n t h e oldest grade. T h e crude fiber decreases from 1 0 . 2 j per cent t o 7.1 j per cent on t h e drained peas, water-free basis. T h e per cent of sugar seems t o decrease with maturity. T h e reason is not a p p a r e n t a n d should be a field for further study. T h e p a r t played b y selective absorption in determining t h e location of added constituents is one requiring further study. T h e change in ash is very slight. T h e composition of t h e ash seems t o remain t h e same throughout t h e growth of t h e pea. (Credit is due t o C. F. Coffin, Jr., for much of t h e analytical work reported in this paper.) LABORATORIES I N D I A N A STATE BOARDOF HEALTH INDIANAPOLIS
______ ON THE VALUATION OF LIME-SULFUR AS AN INSECTICIDE B y HERMANV. TARTAR Received January 10, 1914
A t t h e present time, t h e object of t h e examinations made of samples of commercial lime-sulfur solution in different chemical laboratories throughout t h e country, is t o ascertain d a t a regarding composition. I n m a n y cases, simply t h e total lime content, total sulfur content a n d specific gravity are ascertained. Oftentimes, however, quantitative determinations are also made of t h e different forms of sulfur in combina-
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
3 14
tion. Entomologists a n d horticulturists, making field experiments, generally use a gravity test only A large proportion 06 t h e lime-sulfur used is for insecticidal purposes. Consequently, examinations made in t h e valuation of t h e same should be q u a n titative determinations of those properties from which t h e spray derives its insecticidal value. Actual chemical composition is a secondary m a t t e r except in so far as i t m a y be a n indication or measurement of these properties. F o r this reason, t h e determination of specific gravity is perhaps of little value except in a very general way. Samples of lime-sulfur having t h e same specific gravity may not be alike in chemical composition nor in m a n y other properties. For example, a sample having a low specific gravity may have a greater per cent of polysulfides t h a n a sample having a somewhat higher specific gravity. I n this discussion of valuation, i t is well first t o consider t h e properties which give t o lime-sulfur its insecticidal value. T h e most exhaustive investigation available is, perhaps, t h a t of Shafer.’ H e showed t h a t with scale insects, like S a n Jose scale, t h e calcium polysulfides present in t h e solution soften t h e so-called wax a b o u t t h e margin of t h e insect and, on drying, cause i t t o stick t o t h e plant. I n t h e cases tried, t h e insects stuck tightly enough t o cause also t h e death of t h e young b y sealing t h e m under t h e scale covering of t h e mother. Shafer’s work also strongly indicated t h a t one of t h e principal, if not t h e principal, insecticidal effect of lime-sulfur solution, upon insects of t h e t y p e mentioned, is its great power of absorbing oxygen, t h u s causing t h e treated insects t o suffer because of a n insufficient supply of this element. Other experiments made b y Shafer showed t h a t sulfur dioxide is not “formed in appreciable amounts from sulfur deposited by lime-sulfur except a t temperatures much above those found under spraying conditions in t h e orchard.” T h e liberation of this gas is, evidently, not in amounts large enough t o make i t of importance in a n y consideration of the insecticidal properties of t h e spray. T h e work done b y t h e Department of Entomology of this station2 indicates clearly t h a t the principal insecticidal constituents are t h e calcium ’polysulfides. Experiments tried with calcium thiosulfate on San JosC scale3 showed this material t o have b u t little, if a n y insecticidal value. Wellington‘ arrived at similar conclusions. Shafer’s5 results also indicated t h a t t h e thiosulfate has a limited insecticidal efficiency. I t has been known for long, too, t h a t with certain insects, free sulfur has some killing power. It is stated t h a t d r y sulfur has been used in California perhaps a quarter of a century against almond-red spider. T h e experimental work carried on by t h e experts of t h e California Agricultural Experiment Station6 a n d t h e Bureau of Entomology, U. S. Dep a r t m e n t of Agriculture’ shows t h a t towards certain 1 2
‘
Mich. Agr. Exp. S a . . Tech. Bull. 11. Unpublished results. “Biennial Crop Pest and Hbrticultural Report,” p. 112 (1913). Mass. Agr. Exp. Sta., Bull. 116.
6
Lac. cit. Calif. Agr. Exp. Sta., Bulls. 154 and a34.
7
Private correspondence.
J
I
Vol. 6, N o . 4
insects free sulfur has marked insecticidal properties. There is also t h e possibility t h a t hydrogen sulfide, a gas poisonous t o insects, m a y be liberated from lime-sulfur when i t combines with t h e carbon dioxide of t h e atmosphere or t h a t given off in t h e breath of insects. So far as t h e writer knows, n o means has been found t o ascertain t h e extent t o which this occurs. Experimental work carried o u t a t this laboratory, however, indicates t h a t if hydrogen sulfide is liberated under normal conditions i t is in very small quantity, a n d , evidently, is n o t a n i m p o r t a n t m a t t e r to consider here. From t h e discussion preceding, i t appears t h a t , in general, t h e insecticidal properties of lime-sulfur are due principally t o t h e following-named properties: ( I ) Its power t o t a k e up large a m o u n t s of oxygen, ( 2 ) i t s ability t o soften t h e newly secreted wax a t the margin of scale insects, a n d (3) t h e a m o u n t of free sulfur formed in its decomposition. If this be true, t h e n t h e question of t h e correct valuation resolves itself into t h e quantitative measurement of these factors. T h e a m o u n t of oxygen consumed depends upon reactions as represented in the following equations : Cas6 3 0 --+CaS203 3s Cas4 3 0 --f CaSzOa ZS Cas203 ---f C a S 0 3 S Casos‘ 0 CaS04 T h e combination of oxygen with t h e moist polysulfides is very rapid a n d quantities of the t e t r a sulfide or pentasulfide containing t h e same a m o u n t of calcium would absorb t h e same a m o u n t of oxygen a n d consequently produce t h e same a m o u n t of thiosulfate. This last named substance decomposes very slowly under ordinary conditions. For this reason, calcium sulfite is formed very gradually a n d t h e oxygen required t o form t h e sulfate is absorbed slowly; too slowly, in t h e writer’s opinion, t o make it of insecticidal importance. Investigations made b y t h e entomologist of this station indicate t h a t calcium sulfite has practically n o insecticidal effect upon San Jos6 scale. T h e oxygen required t o convert t h e polysulfides present in a given solution into thiosulfate can be estimated easily b y use of t h e methods of Harris.’ T h e titration used in t h e determination of “monosulfide” (for explanation of this t e r m see bulletin referred t o ) sulfur may be used in estimating t h e a m o u n t of oxygen which will combine with t h e polysulfide present to form thiosulfate. I n this case, I cc. of tenth-normal iodine is equal t o 0.0024 gram of oxygen. T h e writer suggests t h a t this oxygen-consuming capacity might he expressed as t h e “oxygen number’’ (analogous t o t h e iGdine number of fats), this t e r m meaning t h e a m o u n t of oxygen consumed expressed as per cent of t h e lime-sulfur solution, or, in other words, t h e number grams of oxygen absorbed by I O O grams of lime-sulfur. Free sulfur is liberated from lime-sulfur by reactions represented by t h e following equations:
+ + + *
1
Mich Agr Exp. Sta , Tech. Bull. 6.
+ + +
Apr., 1 9 1 4
T H E J O U R N A L OF INDLTSTRIAL A N D ENGINEERING C H E M I S T R Y
+ +
+ + +
Cas4 3 0 --t Cas203 ZS Cas6 3 0 -+ Cas203 3s CaSzOI CaSO3 S Since t h e oxidation of t h e polysulfide takes place rapidly there is a correspondingly rapid deposition of sulfur. T h e liberation of sulfur due t o t h e decomposition of t h e thiosulfate is much less rapid. Considering everything, however, i t appears t h a t all of t h e sulfur liberated might be of equal insecticidal value; a t least, there is n o good evidence available t o t h e contrary. T h e chemical estimatian of t h e sulfur which will be deposited from a given a m o u n t of lime-sulfur solution can be made without difficulty. All of t h e sulfur present in t h e polysulfides in excess of t h a t necessary t o form t h e “monosulfide” of calcium combined in this form, would be deposited; also onehalf of t h e sulfur present as thiosulfate in t h e original solution. T h e chemical methods for making these determinations have already been worked o u t in a thorough manner’ a n d i t is unnecessary t o go into a detailed discussion of t h e m here. T h e a u t h o r suggests t h a t t h e total free sulfur which would be deposited might be expressed as t h e “available sulfur number,” this t e r m meaning sulfur deposited expressed as per cent of t h e original lime-sulfur solution. T h e third insecticidal property mentioned above is not so easily estimated. I n fact, i t is not definitely known why t h e spray solution softens t h e so-called wax on scale insects. I t might be stated, however, t h a t calcium thiosulfate is neutral in solution a n d gives n o caustic effect on t h e hands, while solutions containing calcium polysulfide are very caustic. It is t r u e t h a t there is a small a m o u n t of calcium hydroxide in lime-sulfur solutions, d u e t o hydrolysis of t h e polysulfide, b u t i t is present i n insufficient q u a n t i t y t o say t h a t t h e caustic properties a r e d u e t o t h e alkalinity of t h e solution. T h e writer’s experience in handling t h e s p r a y simply verifies t h e correctness of Shafer’s s t a t e m e n t t h a t “ t h e so-called caustic action of t h e wash on t h e hands seems rather due t o its strong reducing power (power t o absorb oxygen)2 t h a n t o t h e alkalinity of t h e solution.” I t is very possible t h a t this reducing power m a y also cause t h e softening of t h e so-called wax o n the scale insects. If this be true, t h e “oxygen” number mentioned above would give its quantitative measurement. A t a n y rate, t h e power of t h e s p r a y t o soften t h e so-called wax is evidently due t o some property of t h e polysulfides a n d in t h e light of present knowledge no definite s t a t e m e n t can be made regarding i t s exact nature nor its exact quantitative analytical measurement. I n conclusion, the writer wishes t o s t a t e t h a t t h e above discussion is merely a suggestion t o chemists a n d entomologists. There m a y be other insecticidal properties of t h e spray t h a n those mentioned a n d i t is possible t h a t t h e ordinary methods of valuation now in use are t h e best. If not, t h e discussion given here may prove t o be of some value.
*
CHSMICAL LABORATORY AGRICULTURAL EXPERIMENT STATION, CORVALLIS. OREGON Jour. A m n . Chem. SOC.,27 (19051, 244; THISJ O U R N A L , 2 (IYIU). 271; Mich. Agr. Exp. Sta.. Tech. Bull. 6. * Words in parentheses inserted by the uuthor. 1
315
A STUDY OF THE METHODS FOR EXTRACTIONS BY MEANS OF IMMISCIBLE SOLVENTS FROM THE POINT OF VIEW OF THE DISTRIBUTION COEFFICIENTS. I By J. W. MARDEN
Received December 12. 191.1
I t has been found b y Berthelot a n d Jungfleischl a n d later by Nernst2 t h a t when a substance is shaken with two immiscible solvents in which i t is mutually soluble, t h a t i t always distributes itself between t h e two in a definite ratio.3 T h e y found, however, t h a t this is t r u e only when t h e molecular state of t h e solute is t h e same in both solvents, t h a t is, when t h e substance does not polymerize in either solvent or polymerizes t o t h e same extent in both, a n d t h a t t h e ratio of t h e con centrations remai.ns t h e same a t a given temperature, irrespective of t h e amounts of solute present. I t has furthermore been found t h a t if there are two or more substances in solution, this ratio is t h e same as if each substance were present alone. This ratio is called t h e partition or distribution ratio for t h e particular solute a n d pair of solvents. This ratio has been used in physical chemistry chiefly as a method for t h e determination of molecular weights a n d for t h e determination of chemical equilibrium. If, however, substances distribute themselves between two solvents always in t h e same ratio, i t is easy t o see t h a t this ratio could be used t o calculate t h e number of times t h a t t h e one solvent must be shaken out with t h e other t o extract all b u t 0.1 per cent of t h e material in question. If we let ( d ) = t h e distribution ratio, t h e n in t h e case of ether a n d water, where t h e volumes are t h e same, concentration in ~ water - _ _ - CI = constant = ( d , C? concentration in ether If we let ( a ) = t h e volume of aqueous solution, ( e ) = t h e volume of ether added, ( X O ) = t h e initial concentration in t h e aqueous solution a n d ( X I ) , (xz),(x,) = t h e concentration after I , 2 , n , extractions, then,
solving for
XI,
we get x , = no(
after a second extraction, x’ = d ( a x2
----)
da e + d a ’ x -l
--),
- - nz c
= n l ( e +ddaa )
after n extractions, xn =
d(L ids)
.
F r o m this i t is t o be seen t h a t , although complete Ann. chim. Dhys.. 141 26 (1872), 396; Berthelot, I b i d . , p . 408. Z. p h y s i k . Chcm., 8 (1891). 110. I Nernst, “Theoretische Chemie” 11909). y. 494; Morgan. "Physical Chemistry” (1908), p. 7.01. 1
’
