Yoshikane Kawasaki

Thermodynamic properties of binary mixtures : hexamethylphosphoric triamide+a polar liquid at 25°C

Excess enthalpies HmE excess isobaric heat capacities Cp,m′E, densities, and speeds of sound of hexamethylphosphoric triamide (HMPA)+acetonitrile (AN), + N,N-dimethylformamide (DMF), and + dimethylsulfoxide (DMSO) were measured at 25degrC. HmE=−1200 J-mol−1 for HMPA + AN, −180 J-mol−1 for HMPA + DMF, and 75 J-mol−1 for HMPA + DMSO Cp,mE is positive and considerably larger than Cv,m′E. VmE for HMPA + DMSO was small and changed sign from negative to positive around HMPA mole fraction x=0.6. VmE for the other two mixtures were negative. The excess compressibilities, KmE for the other two mixtures were negative. The excess compressibilities, KSE and KTE were similar to VmE

Unusual formation of 5-halo-2,2′-bipyridyls by treatment of tris(2-pyridyl)phosphine derivatives with halogens

Abstract Reaction of tris(2-pyridyl)phosphine with chlorine in dichloromethane or acetonitrile gave chlorotris(2-pyridyl)phosphonium chloride which afforded a coupling product, 2,2′-bipyridyl, by treating with dilute HCl. Treatment of tris(2-pyridyl)phosphine or tris(2-pyridyl)phosphine oxide with chlorine or bromine in methanol gave unusual 5-halo-2,2′-bipyridyl as a major coupling product. This is undoubedly an electrophilic substitution on a pyridyl ring in the pentacovalent phosphorane.

THERMODYNAMIC PROPERTIES OF BINARY MIXTURES : HEXAMETHYLPHOSPHORIC TRIAMIDE (HMPA) WITH A NON-POLAR LIQUID AT 25C

Excess isobaric heat capacities CpE, densities π and speeds of sound u of HMPA+heptane and+benzene were measured at 25°C. CpE of both mixtures were positive in the range of small x and negative in the other region. The mixture containing benzene showed higher CpE than the heptane mixture. They both exhibited considerably smaller CVE than CpE. VE was positive for HMPA+heptane and negative for HMPA+benzene. The compressibilities KsE and KpE of both mixtures were negative. In both mixtures, non-random mixing is expected and [(CH3)2N]3PO molecules are inhomogeneously distributed.

Preparation of 5-Halo-2,2′-Bipyridyls

Abstract Earlier, we have shown that treatment of tris(2-pyridyl)phosphine1) or tris(2-pyridy1)phosphine oxide2 with 2-pyridyllithium resulted in the formation of ligand coupling products, namely 2,2′-bipyridyl, as shown below.

Preparation and Properties of PVC/Polymethacrylate Graded Blends by a Dissolution - Diffusion method

We prepared and characterized PVC/polymethacrylate graded miscible blends by a dissolution-diffusion method, and found that those have high thermal shock resistance and our prediction model can be adopted to those graded structures.