Oct., 1941
OXIDATION
depend on approximately the first power of acid concentration, there are numerous instances of other acid-catalyzed reactions in which the dependence has been found to be complex.12 Except for one instance which appears anomalous, the data in Tables IIIa and IIIb indicate no significant change in velocity caused by variation of chain length. This constitutes further support for the earlier assumption that degradation of the chain during the reaction is without appreciable effect in so far as the kinetics of alcoholysis are concerned. According to equation (2), the rate of appearance of polyvinyl alcohol divided by the initial concentration of polymer (xo) a t any given value of x should be a constant. Tables IVa and IVb show that this condition is approached in dilute solutions. With increasing polymer concentration, there is a well-defined downward drift of the values of K . Since an over-all change in concentration of eightfold causes only about a 25y0 change in the relative rate of alcoholysis, it may be concluded that the deviations in more concentrated solutions of the polymer are due to secondary causes. (12) See, e. 2135 (1913).
g.,
2721
PRODUCTS OF A9*"-&TALIN
H. Dawson and F. Powis, J . Chcm. SOC.,108, 11,
From Fig. 5 it is seen that the data conform to the Arrhenius equation. It thus appears likely that all of the rate constants K , appearing in the scheme represented by equation (3) have approximately the same dependence on temperature.
Summary 1. The alcoholysis of polyvinyl acetate in absolute methanol has been studied, using both hydrogen chloride and sodium hydroxide as catalysts. 2. The reaction possesses apparent autocatalytic characteristics, which may be due either to an autocatalytic or to a stepwise nature. 3. The reaction rate is dependent on the first power of the concentration of the basic catalyst, and on the 1.22 power of the concentration of the acidic catalyst. 4. The reaction rate is further dependent upon approximately the first power of the polymer concentration, independent of the molecular weight of the polymer, and responds to temperature changes according to the Arrhenius equation. 5. A qualitative explanation of these relationships is suggested. ROCHESTER,
[CONTRIBUTION FROM T E E CHEMICAL
N. Y .
RECEIVED JULY 30, 1941
LABORATORY OF HARVARD UNIVERSITY]
Oxidation Products of AgJo-Octalin BY WILLIAMP. CAMPBELL AND G. CHRIS HARRIS This work was initiated for the purpose of find- of P-decalol and isomerization of the resulting ing a suitable method of preparing the octalone-1 octalin by means of phosphoric acid and phoswhich has been designated by Hiickel and Naab' phoric anhydride. The yield of A9*l0-octa1in from as the A9~'O-isomer. I n addition it was planned P-decalol was 78%. Although we have obtained to prepare intermediates such as Ag~lo-octalol-l the known blue nitroso chloride derivative3c of which, along with the known 9,lO-dihydroxydeca- A9*10-octalinfrom our product, the possibility lin, may be converted by dehydration into differ- that small amounts of isomers are present2 is by ent isomeric hexahydronaphthalenes. The latter no means excluded. are of interest as model compounds for the many The desired octalone-1 has been obtained by natural products which contain this diene system. the action of nitrous acid on 9-amino-A4*l0-octalin For the preparation of A9~'O-octalinthe method and by the chromic acid oxidation of A9,10-octalin.1 of Linstead et al.210was followed although certain More recently i t has been made by cyclization of modifications which appear to be essential were y-( AI-cyclohexeny1)-butyric acid.4 We have obmade. The method consists of the dehydration tained the same substance in 45% over-all yield by the following series of reactions. The oxida(1) Hiickel and Naab, Ann., 104, 136 (1933). (2) Linstead, Wang, Williams and Emngton, J . Chcm. SOC.,1136 tion of A99'O-octalin with selenium dioxide in the (1937). presence of acetic anhydride at 5' gave the ace(8) Other methods for the preparation of A9~~0-octalin:(a) Nametkin and Gaglow, Bcr., 62, 1570 (1929); (b) Durland and Adtate of A9~10-octalol-l (11)in 65% yield. Hydrolykin%THIS JOURNAL, 61,429 (1939); (c) Hiickel, Danneel, Schwartz and Gercke, Ann., 474, 121 (1929).
(4) Nenitzescu and Przemetzky, Bcr., 74, 676 (1941).
WILLIAMP. CAMPBELL AND G. CHRISHARRIS
2722
sis of this product followed by an Oppenauefl oxidation of the alcohol (111) gave the octalone. The identity of this product with that previously reported was established by conversion to the oxime and semicarbazone. OCOCH,
e
OH
A rearrangement of Ag~lo-octalone-l (V) to the A8i9-isomer might be expected if one assumes that enolization of the Ag~lo-compound occurs to an appreciable extent. The enol form (VI) possesses an unstable arrangement of the double 0 OH OH 0
-x"i__ &@
\ I
I1
I11
IV
The double bond in this octalone had been placed' a t 9,lO because of the formation from AY3lo-octalin(I) and because rearrangement to another position was considered unlikely. We have obtained evidence based on the ultraviolet absorption spectrum of our sample, which shows the substance to be A*.9-octalone-l (IV). The curve (Fig. 1, curve 2) shows a maximum at 243 mp (log E = 4.0) characteristic of an a,p-unsaturated ketone and one a t 305 mp (log E = 1.8) which is due to the carbonyl group. The
Vol. 63
\J
1_ A)
/ V
VI
VI1
IV
bonds and would be expected to isomerize to the more stable distributed form (VII) quite readily. An analogy for this kind of shift is found in the conversion of cholestenone (VIII) into the enol acetate (IX).' Although hydrolysis, in this case,
i
CH&!OO/\
0' \/
IX
would regenerate the original ketone because the double bond would return to a position of conjugation with the carbonylI8a shift of this kind would not be expected to occur in the octalone where conjugation is attained without rearrange8 b4 ment. 1.8The double bonds in the octalol-1 (111) and the acetate (11) are very probably in the 9,lO position. The compounds are formed from A"'O-octalin 1.0 and no reason for postulating a shift of the double bond is apparent. In addition, further oxidation of the acetate by selenium dioxide takes place in Wave length, mp. the 5-position1as would be expected if the double Fig. I.-Absorption spectra: la and b, 1,2,3,5,6,7bond is a t 9,lO. While this evidence is not conhexahydronaphthalenediol-1,5diacetate and the diol, respectively; 2, A8'9-octalone-l; 3, Ae~10-octalindione-l,5. clusive, it strongly indicates a 9,lO double bond. The A8~9-octalone-lpossesses an asymmetric former falls within the range (234 to 244 mp) which carbon atom a t GOand might be capable of resoluwas recently shown by Woodward6 to be char- violet absorption curves have been determined, possess an exocyclic acteristic of a,B-unsaturated ketones having one carbon-carbon double bond, whereas AY'ln-octalone possesses no bond. This variation in structure may place the most probhydrogen on the doubly-bound carbon atoms. such able maximum for AQ"0-octalone a t about 247 mp. This work rendThe only octalone-1 which meets this requirement ers the value obtained for our ketone, 243 mp, inconclusive and further evidence is necessary before a definite decision between the 8,9 is the As,g-derivative(IV).& and 9,lO positions of the double bond can be made. Unfortunately,
I,
