INTERRELATIONS OF THE ENERGETICS OF AMIDES AND ALKENES - ENTHALPIES OF FORMATION OF N,N-DIMETHYL DERIVATIVES OF PIVALAMIDE, 1-ADAMANTYLCARBOXAMIDE AND BENZAMIDE, AND OF STYRENE AND ITS ALPHA-METHYLATED, TRANS-BETA-METHYLATED AND BETA,BETA-METHYLATED DERIVATIVES

The enthalpies of formation of the condensed phase and gaseous N,N-dimethyl derivatives of pivalamide, 1-adamantylcarboxamide and benzamide were determined by combustion calorimetry and the associated enthalpies of vaporization and sublimation. The enthalpies of formation of styrene and its alpha-, trans-beta- and beta,beta-methylated derivatives were determined from measurements of their enthalpies of hydrogenation in dilute hydrocarbon solution. Strain and resonance effects of amides and alkenes are discussed in terms of the exo-/endothermicity of the following reactions: CH3CONH2(g) + RC(CH3)=CH2 --> (CH3)2C=CH2(g) + RCONH2(g) CH3CON(CH3)2(g) + RCH=C(CH3)2(g) --> CH3CH=C(CH3)2(g) + RCON(CH3)2(g) and in terms of the difference of enthalpies of formation of the isomeric (Z)- and (E)-RCH=CHCH3.