Transformation of 3-formylchromones into pyridines and pyrroles

Interaction of 3-formylchromones with ethyl aminoethanoate provides a novel route to pyridines and pyrroles.     

A mass spectrometric investigation of the reduction product of 3H-1,2-benzodithiole-3-thione

A combination of electron impact, chemical ionization, field desorption and field ionization mass spectrometry has been employed to demonstrate that the LAH reduction product of 3H-1,2-benzodithiole-3-thione is the dimer, dibenzo[c,h]-3H,10H-dihydro-1,2,8,9-tetrathiecine.     

Energy Planning and Policy

Journal of the Operational Research Society -     

A nuclear magnetic resonance study of toluene-polyisobutylene solutions. 2. Vrentas-Duda theory

The self-diffusion coefficients of toluene in polyisobutylene have been analyzed using the Vrentas-Duda free volume diffusion model. The diffusion coefficients were determined at different temperatures and concentrations, using the pulsed field gradient nuclear magnetic resonance technique. The data were satisfactorily described by the model and the size of the polymer jumping unit was extracted. Comparisons were made with the Fujita free volume theory and the Fujita free volume parameters were extracted from the Vrentas-Duda free volume parameters. From the diffusion data that now available, it can be concluded that for most polymers the jumping unit is about 1.5 times the polymer monomer molecular weight. The activation energy of the toluene diffusion in polyisobutylene is compared with the activation energies of other penetrants in the same polymer. The diffusion data presented in this work show that the energy per mole required to overcome the attractive forces which constrain a diffusing species to its neighbors should be considered to be zero, in order to be able to extract the free volume parameters (from viscosity and diffusion data) with an acceptable uncertainty. ©1995 John Wiley & Sons, Inc.