V O L U M E 24, NO. 8, A U G U S T 1 9 5 2 Table 11’.
1359
It will be noted that the decrease in the amount of apparent pyrethrins found on the coated paper is as great as 80%. Coated papers 1 and 2 in Table IV were of unknonn origin and no history was available other than that they were early experimental production. Ho\rever, coated paper 3 was of recent manufacture and was coated by the manufacturer to contain approximately 6 nig. per square foot. The results of analysis using the Skellysolve F wash averaged 5.8 mg per square foot, which is consistent with the manufacturer’s claim. The results of analysis v ithout this IT ash averaged 23.0 mg per square foot and indicate the presence of large amounts of interfering substances which must be removed. The uncoated paper still shows a slight color development even after a Skellysolve F extraction. Although this value iq small, it is desirable to run a control analysis on untreated kr:ift paper of the same origin as the treated bags whenever possible
Effect of Skellysolve F Extraction .4pparent Pyrethrins, 11g. N o extraction Extraction
Pyrethrum concentra.te Purified Crude (20%) Coated paper KO. 1 XO. 2 No. 3 Untreated paper
so.1 so. 2
1.26 2.57
1,25 1.97
2 . .53 3 83 23.0
0 49 i.75 J 8
1.05
0.15 0.09
0 71
plcte, since continued extraction of the samples for periods as high as 6 hours showed no additional pj-rethrins when the extracsts were analyzed. Because continuous heating of the alcoholic solution of pyrethrins might be causing loss through thermal deconiposition, a series of tests was run using aliquots of a standard solution of pyrethrins. One series of aliquots was analyzed directly without heating and the second and third series were placed in extraction apparatus and heated for 3 and 6 hours, respectively. Subsequent analysis shon-ctl no cpintitative difference in color developed in these three series. The alcoholic extract of thc papor is r\tract,ed with Skellysolve F in the preparation of thp sample for color development in order to separat,e thc pyrethrins fmm insecticidally inert related conipounds which are extracted from the paper by alcohol but are not soluble in Skellysolve F. This Skcllysolve F extraction is further necessitated by a similar soluliilit,y of other esters which \yere found in t8hekraft paper and sizing. The results obtained with and without this Skellysol~eF extraction are sh0n.n in Table I\-.
ACKNOWLEDG.VlENT
The authors are indebted to Elmer E. Fleck and to Paul A. Giang, of the Bureau of Entomology and Plant Quarantine, the former for many helpful suggestions, and the latter for X.O.A.C. analyses. LITERATURE CITED
(1) Assoc. Offic. Agr. Chemists, “Methods of .Inalysis,” 7th ed.,
Method 5 : 114, Washington, D. C., 1950. ( 2 ) Lord, K . il., Sature, 165, KO.4197, 567-8 (1950). RECEIVED for review February 27, 1951. Accepted M a y 8, 1952. Presented before the Division of Agricultural and Food Chemistry at t h e 121st \feeting of the AMERICAN CHEMICAL SOCIETY,Milwaukee. \Tis.
An Anomaly in the Zeisel Methoxy Determination R. L. HUANG AND FRANCIS MORSINGH Cnirersity of Malaya, Sinfiapore, Malaya
lII1 Zeisel method L generallj- regarded as specific for oxygroups, carbon-methyl groups usually being ge:-methyl determined by the Kuhn-Roth method. While engaged in a search for new estrogenic substance3, the authors synthesized the diphenol (I, Table I j and found, rather surprisingly, that though devoid of methoxy groups. it nevertheless gave a small but, definite value for “methoxy” using the Zeisel method. Siniilar substances (11) and (111 have been prepared and found to behave in the same n-aj.: the valuer of methoxy found, though not constant, correspond to roughly one quarter of a inole of methyl iodide being formed from one mole of suhstance analyzed
(see Table I). It is noteworthy that the trialkyl derivative (Y),synthesized and analyzed some years ago (3),did not, give any methoxy under the same conditions of analysis, while the value found for the dimethoq- derivative (IV) agreed crith t,he calculated value. Hence, it appears that this behavior is peculiar to the fully methylated dibenzL-Is such as (1) and constitutes an instance in ivhich the specificity of the Zeisel methosy determination is questionahle. [a similar anomaly has been observed in D-mannitol ( I ) . ] The effect of tetra-alkylation hy g r o u p other than methyl might be 15-orth study. Compound (1111 was prepared by the method of Farmer and Moore ( 2 ) ; the synthesis of ( I ) , hy three different methods, and of (11) arid (IY)will he published elsewhere. Results of Zeisel llethouy Determinations on Various Compounds ~~
Tahle I.
.kCKZIOWLEDGMENT \-/
Substance
--Analy&_
-_
c, 56
Calcd. 2,3-l)iinethyl-2,3-di (p-hydroxyphenyl) butane (I)
50.0
2,3-Diinethyl-2,3-di (p-nitrophenyllhutane (11) 2,3-Dimethyl-2..3-diphenylhiitane (111) 2,3-Dim~thyI-2.3-di(p-methoxypheny1)hutane iI V) 2->Iethyl-2,3-di (p-hydroxyp1ienyl)pentane i V )
6.i.8
Found 80.0 6.5 6
H, % -~ Calcd. Found 8.15 8.21 6.10
\-/
1
_ ~_ _~.-
s,%
Calcd.
Found
..
~~~~
O l l e . “c Calrd. Found 0 3.10, 3.76, 4.32 0 1.88
5 94
8.53
8 20
..
..
..
.
..
20.8
..
0
80.3
80.2
8.79
8.74
80 0
75.6
8 15
8.00
,
0
3.33
20.4 0
The authors thank the Shell Co., Ltd., for a fellon-shill awarded to Francis Morsingh. Microanalyses were carried out by If-eiler and Strauss of Oxford, England. LITERATURE CITED
*X.raki,T., and Ilasi, T., J . C h e n ~ hoc. . J a p a n , 61, 99 (1940) ( 2 ) Farmer, E. H., and Moore, C . G., J .
(1)
Chem. SOC.,1951, 141. ( 3 ) Huang, R. L., Ph.D. thesis, University of Oxford, England, 1 9 4 i . RECEIVED f o r review Fehruary 21, 1932. cepted May 1 , l(152.
Ac-
