The dielectric constant e' and dielectric loss e' of several mixtures of propionaldehyde-polyethylene glycol (system 1) and benzaldehyde-polyethylene glycol (system II) have been measured within the frequency ...The dielectric constant e' and dielectric loss e' of several mixtures of propionaldehyde-polyethylene glycol (system 1) and benzaldehyde-polyethylene glycol (system II) have been measured within the frequency band 105-107 Hz and the temperature range 20-50℃. The dielectric behaviour is discussed. on the other hand, the dielectric relaxation time T. activation energy △He, and entorpy change △Se for the dielectric relaxation as well as activation energy of viscous flow △Hv are calculated for the same temperature range. It is suggested that the observed increase in T values with increas.ng glycol content is due to an increase in the hydrogen bonding in the aggregates or clusters which would be formed between the carbonyl group of the aldehyde and the hydrogen atoms from the glycot molecules. In addition， the higher values of T, △He, and △Se in case of system (II) than that in case of system (I) may be due to the greater volume of the aggregates and the stronger dipole-dipole forces in system (II) compared with those in system (I).展开更多
This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP comple...This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes,providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield(up to 97%) and branched-regioselectivity(up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.展开更多
文摘The dielectric constant e' and dielectric loss e' of several mixtures of propionaldehyde-polyethylene glycol (system 1) and benzaldehyde-polyethylene glycol (system II) have been measured within the frequency band 105-107 Hz and the temperature range 20-50℃. The dielectric behaviour is discussed. on the other hand, the dielectric relaxation time T. activation energy △He, and entorpy change △Se for the dielectric relaxation as well as activation energy of viscous flow △Hv are calculated for the same temperature range. It is suggested that the observed increase in T values with increas.ng glycol content is due to an increase in the hydrogen bonding in the aggregates or clusters which would be formed between the carbonyl group of the aldehyde and the hydrogen atoms from the glycot molecules. In addition， the higher values of T, △He, and △Se in case of system (II) than that in case of system (I) may be due to the greater volume of the aggregates and the stronger dipole-dipole forces in system (II) compared with those in system (I).
基金financial support from the National Natural Science Foundation of China (No.21902032)。
文摘This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes,providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield(up to 97%) and branched-regioselectivity(up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.
