PRAKASH S. NANGIAA N D SIDNEY W. BENSON
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ture with the hydrogen on the nitrogen of ring 11, structure I1 of Fig. 7 is proposed for PheHz620. The spectrum of PheHz620 is furthermore almost identical with t h a t given by Woodward for a phlorin base34; the proposed structure differs from the phlorin structure (34) R. B Woodward, I n d Chcm Beige, 27, 1293 (1962)
Vol. 86
only in t h a t the @-pyrrolepositions of ring IV are reduced. Acknowledgment.--R'e are indebted to Xlr. John hiiller for the preparation of ethyl chlorophyllide a from Jimson weed and for its chromatographic purification,
[ CONTRIBUTIOX FROM THE CHEMISTRY DEPARTMENT, UXIVERSITY OF SOUTHERN CALIFORNIA, LOS ASGELES7 , CALIFORNIA]
The Thermodynamics of the Dehydrogenation of Propane by Iodine Vaporla BY PRAKASH S. NXNCIAA N D SIDNEY W. BEN SON'^ RECEIVED J A N U A R Y 2, 1964
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I n the range 308 t o 340' the gas phase reaction, 1 2 C3Hs + 2HI C3H6, proceeds quantitatively to equilibrium with no side reactions. From the measured compositions a t equilibrium it is possible t o calculate values of K with a n estimated precision of zk3
