Origins of thermodynamic stability of urea:alkane inclusion compounds
Article Abstract:
Thermodynamic stability of inclusion compounds of the urea:alkane type has been studied using existing thermodynamic data. Three alkane guests, decane, hexadecane and dodecane, were used. Up to their melting points, the inclusion compounds are thermodynamically stable relative to the component species. The solid-solid phase transitions have only a minor role in stabilization. The thermodynamic stability is mostly driven enthalpically. Above the melting point of the guest species, the inclusion compounds become far less stable as a result of competition from the liquid guest, and the destabilization brings incongruent melting as time goes on. At a given temperature, stability of the decane inclusion is lowest, and of the hexadecane is greatest, leaving that of dodecane in the middle.
Publication Name: Canadian Journal of Chemistry
Subject: Chemistry
ISSN: 0008-4042
Year: 1998
User Contributions:
Comment about this article or add new information about this topic:
The ultra high pressure conjugate addition of indoles to electron-deficient olefins
Article Abstract:
The addition to a series of Michael acceptors, that is, electron-deficient olefins, of indole and methyl indole at ultra-high and high pressures and ambient pressures in the presence of ytterbium triflate has been studied. Under ambient pressure less sterically hindered and more reactive electrophiles yielded 3-alkylated indoles, as expected, in yields that were good to excellent. The Michael acceptors that were more difficult were subjected to pressures of 13 kbar and in all cases a dramatic reduction in reaction product resulted. Products were characterized using single-crystal X-ray diffraction. Enals tended to polymerize.
Publication Name: Canadian Journal of Chemistry
Subject: Chemistry
ISSN: 0008-4042
Year: 1998
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Regular polyhedral molecules: P20 and its inclusion compounds. Potential applications of the boron cluster compounds
- Abstracts: Nature of dynamic processes associated with the [S.sub.N]1 reaction mechanism. Surface chemistry of transition metal carbides
- Abstracts: Time-resolved dynamics of proton transfer in proteinous systems. Theoretical studies of chemical dynamics: overview of some fundamental mechanisms
- Abstracts: Dynamics of silicate exchange in highly alkaline potassium silicate solutions. Structure and dynamics of azapropazone derivatives studied by crystallography and nuclear magnetic resonance
- Abstracts: The self-assembly of a layered material: metal-alkanethiolate bilayers. Remarkable kinetic stability of alpha-thiocarbamoyl substituted 4-methoxybenzyl cations