Nov. 5. 1962 RHODIUM SALTS AS BUTADIENE P O L Y M E R I Z A T I O N C a T A L Y S T S 4145 (iii) A portion of the reactants disappears to give material other than CbHg isomers a t a rate which is nearly independent of time. Evidently both cis and trans isomers participate in this reaction which presumably gives high boiling material.(iv) Beyond the maximum in the concentration of cis-pentadiene, the reaction ck-CHs= CHCH=CHCHa + hv d ~uLEs-CH~=CHCH=CHCHI (10) may account for the decrease in the cis isomer.These results give more direct evidence for the statement made in an earlier section that the general reaction2 is probably rapid when compared to the rates of rotation around the carbon-carbon bonds in the molecule. Reaction 8 may be pic-$2 V tured as proceeding through an excited state (V) which is probably the same as the state which leads to the cis isomer through rotation around the bond between C3 and C4. The latter operation has no energy barrier in the excited state up to an angle of r/214 and its rate may be comparable to the rate of rotation around the bond between CZ and Cp. Since the rate of reaction 8 is observed to be faster than reaction 9, it follows that the former is favored by a suitable configuration in the ground state in the molecules which undergo the process. l5Acknowledgment.-The author wishes to thank Dr. Harold L. Friedman for his advice and encouragement during the course of this work. He is grateful to Drs. J. Kumamoto and J. C. Powers for many helpful discussions.
The activity coefficients of molecular salicylic acid have been determined in various aqueous salt solutions.For the hydroxybenzoic acids the "salting-out" constants diverge from the values for benzoic acid as one progresses from salts having the highest "salting-out" effects to salts having the lowest effects.A comparison of the "salting-out" constants for ortho, meta and parahydroxybenzoic acids in potassium chloride solutions shows that the constants decrease with the transfer of the hydroxy group to the meta and para positions, respectively.Philadelphia, Pennsylvania
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.