V O L U M E 2 7 , NO. 6, J U N E 1 9 5 5 -
-
Table 11.
~
-
___
1027 ~
~~
~~~~
liberated acidity is not extremelj. critical, Normalities between 0.05 and 0.2 have proved satisfactory in these Error, laboratories, although O.lA\r seems to L& he ideal for most compounds. 31ore 0 0 concentrated solutions-i.e., 0.5.V, set up 0.9 +O. 1 local escesses of base which are so large f0.1 0 0 that the locally precipitated silver oxide -0 .i iedissolves with considerable difficult!.. -0 2 -0 4 This lengthens the time required for the -0 .i analysis, and also produces a condition which may be more fiivorable for interference by aldehydes. Too dilute hase do not produce a sharp color change a t the end point. cause some acetylide precipitntion.
Effect of Halogens and Aldehydes upon Determination of Acet:lenic H j drogen
3.-11ethyl- 1-pen tyn-3-01
3 180 3 390
2 60; 1 542 2 358 2 6.54 2 730 3 313
3 430
3 180 3 390
2 671 1 543 2 358 2.640 2 724 3 300 3 114
Iodide Chloride Bromide Butyraldehyde Butyraldehyde Formaldehyde Formaldehyde Salicylaldehyde Salicylaldehyde
Reagent AgNO1
ii . 0
3.0 3.0 0,544
AgNOl
4gNOu AgNOa .4gC101
0,833
AgN0.I AgClO, AgKO, Apso,
0.698
0.718 0.088
0.713 ~~
to prevent acetylide precipitation is much less for some conipounds than for others. I n these laboratories, 2-methyl-3-hutyn2-01 and 3-methyl-1-pentyn-3-01 are analyzed rout,inely by t,he addition of 1.5 meq. of saniple to 100 ml. of 0.351 aqueous silver nitrate and subsequent titration of the liberated acidity with O.U.5.V alkali. Under the described conditions no nretylide precipitation is observed. On the other hand, most, hj-drocarhons. suoli as acetylene, 1-hesyne etc., whose acetylides would precipitate from dilute silver solutions, are analyzed utilizing concentrated (2.0 t o 3.5-11) solutions of silver nitrate or silver perchlornte as reagents. The amount of methyl purple indicator added to the solut.ion to i>etitrated is critical. Three or 4 drops from the conventional dropping-type indicator bottle are sufficient when silver nitrate is uied: larger amounts of indicator tend t o obscure the end point. E'u1,ir or 5 drops of indicator may be used when silver perchlorate ii imployed. For many of the compounds tested, a more distinct e d point was obtained lvith silver perchlorate than with silver nitr:ite. The effects of the high salt concentration, in the propr1.d concentrated silver solutions on the indicator, appear to haye ii negligible influence on the accuracy of the method. The wiwtion of appropriate indicators is limited to those which change color in the p H range of 4 t o 6. .4t higher p H values hydrated silver oxide starts t o precipitate. Bromocresol purple, hroii1ocresol green, methyl red, and methyl red-methylene blue iruiicators have been utilized in these laboratories; however, methyl purple is preferred by most of the analysts. Reputedly, c.iilorophenol red ( 1 2 ) has heen employed successfully for this purpose. The concentration of sodium hyclroside used to titrate the
.
solution. and ni:i!.
ACKNOW LEDG31 ENT
The authors are indebted to C. .4.\l*nmser tor valuable aid :inti :issistance during the (Boui'w of this investigation and preparation of this manuscript. .4cknon-ledgment is also estended to A. €1. Taylor and H. IT.Linde for their critical examination of this paper and to the .4ir Reduction Co.. In(*..for permission to puhlish. LITERiTL'RE CITED
Alteri. V. -1.. "Gas -4nalysia and Testing of Gaheous I I a t e i ~ i n l . . " American Gas ;\asoc., Inc.. Xew York, 1945. Chevastelon, It.. C o n ~ p t .r e n d . , 125, 245 (1897). Hanna. G. J., and Siggia, S.. ANAL.CHEM., 21, 1469-70 (1949). Ilosvay. L.u.S., l l e r . . 32, 2697-9 (1899). llarszak. I., and Koulkk, 11.. .116m.services c h i w , P/u( ( I ' u 36, 1-0, 4 . 421-6 (1951). Pifer. C. K., and Wolliah, E. G , , I s . & i . . CHLXI.,24, :300-5 (1932).
Itobey. lt. F..Hudson, 13. E., .Jr., and FYie-e, 13. Isesof Derilatites of Tetramethylbibenzjls
D
U R I S G the synthesis of certain substances related to hesestrol, derivatives of tetramethylbibenzyls (I, R = R' = Me; X = H, SOZ, or OH), although devoid of methouy groups, were found to give small but definite apparent methoxy value. when analyzed for such groups ( 2 ) . The authors present the analytical technique employed. and report that similar anomalies have been encountered in the same type of bibenzyl(1) in nhich the substituents R and R' are alkyl groups other than methjl [substances (11) to (VI), Table I]. However, the structurally related succinonitriles(VI1) and (1'111) do not exhibit this ahnormal behavior under the same conditions of analysis. Except for (5') and (LT), all the reported substances \\ere prepared by free-radical dimerization using di-tert-butyl peroside Compounds (V) and (VI) ere synthesized by a totally different method involving reduction a i t h zinc and hydrogen iodide ( I ) .
R R -ya-(.--c.-x-+-Ay -
R' R' H; R = hle, R' = E t (meso and racwiiic.~ NO*; R' = Et (meso and racemic) OH; R' = E t (meso and racemic) OH; R = R' = Et PhCOO; R = R ' = n-Pr R R
--
~
Melting Point, C .
Methoxy Found, '"0
93 40-1
2 ti 2 2
201-2
3 3 3 li
152 17R
Racemic 3 , 4 - D i - p - h y d r o x ~ p l i e n y l - 3 , 4 - d i e t l i ~ l l i e ~ V) ne~ 4,5-Di-p-benzoyloxyplienyl4,j-di-n-grolJyloctane ( V I ) '7.3-Diphenyl-2.3-dicyanobutane(VII) Neso 3.4-Diphen3.1-3,4-dicyanohezanhe~ane ( V I 11) Meso Race iii i c
1 8 ~.
103-4
is6
'73 2 0
182-3
2.4
224
0
174-5 117-18
0 0
EXPERlAl EYT 4L
The determinations of methosy (3) were carried out, under more vigorous conditions than those normally applied in the estimation after Zeisel. The technique was that normall:; employed for the estimation of S-methyl in an apparatus similar to that of Pregl, except t,hat ammonium iodide was not added. The specimen dissolved in phenol and acetic anhydride waF boiled in hydriodic acid and evaporated t o dryness, and t,he residue heated to above 300' C. In this manner, quantitative results could be obtained in the case of a number of phenolic methosyls, but discrimination between N-methyl and O-met,hj-I rannot be achieved thereby. .4CKNOWLEDGMENT
The authors thank the Shell Co. of Singapore, Ltd., for a research fellowship (to L.K.T.), and G. Keiler and S. B. Strauss for carrying out the analyPe9. LITERATURE CITED
CN ch
R R
= Me (meso) =
E t (meso and racemic)
Huang, R. L., and Kum-Tatt. Lee, J . Chem. SOC..1954, p. 2570. Huang, R. L.. and RIorsingh, F.. ANAL.CHEM., 24, 1359 (1952). (3) Weiler, G., and Strauss, S. B.. Oxford, England, private communication.
(I) (2)
RECEIVED for review April 20. 1954. .Accepted January 12, 1955.
