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8685774 
Journal Article 
Conformational Analysis. XXIX. The Isopropyl Group 
Allinger, NL; Hu, SE 
1962 
Yes 
Journal of Organic Chemistry
ISSN: 0022-3263
EISSN: 1520-6904 
27 
10 
3417-3420 
English 
The thermodynamic quantities for the isomerization of an isopropyl group from an axial to an equatorial position on a cyclohexane ring have been calculated to be: ∆H298° —1.63 kcal./mole, ∆S298° —1.59 e.u., and ∆F298° —2.10 kcal./mole. Equilibrations of the eis and trans isomers of 1,3-diisopropylcyclohexane with palladium at elevated temperatures have been carried out and indicate that while there is considerable deviation between the calculated and experimental values of ∆H° and ∆S°, these differences are compensating, and the correctness of the calculated value for ∆F° was experimentally confirmed. Similar equilibration studies were carried out with 1,3- and 1,4-dimethylcyclohexanes, and the thermodynamic quantities found for these compounds are in agreement with thermochemical values. 1962, American Chemical Society. All rights reserved.