Equation of state for inert gas solids

The equation of state is a fundamental relation to analyse the thermophysical properties of different class of solids and it plays a key role in basic and applied condensed matter physics research. A lot of work has been done in the field of ionic solids, minerals and metals but a very little work is done in the field of inert gas solids. Most of the equations of state failed to explain the properties of inert gas solid because of their abnormal behavior in the low temperature range. In the present paper, Singh-Gupta equation of state has been used to study the properties of these solids. The results obtained using these equations have shown a good agreement with available experimental results. Thus it is shown that these equations of states successfully explain the behavior of inert gas solids.      

A Mild and Efficient Method for Chemoselective Silylation of Alcohols Using Hexamethyldisilazane in the Presence of Silica Chloride

Reaction of alcohols with hexamethyldisilazane in the presence of silica chloride provides efficiently the corresponding trimethylsilyl ethers. This system discriminates absolutely amines and thiols from alcohols.     

Arylidene Polymers. IX. Synthesis,Characterization, and Morphology of New Polyesters of Diarylidenecycloalkanones Containing Thianthrene Units

New polyesters containing thianthrene tetraoxide were synthesized by the interaction of 2,7-dichloroformylthianthrene-5,5′,10, 10′-tetraoxide with 2,5-bis(p-hydroxybenzylidene)cyclopentanone, 2,5-divanillylidenecyclopentanone, 2,6-bis(p-hydroxybenzyiidene)-cyclohexanone, 2,6-divanillylidenecyclohexanone, and 2,7-bis(p-hydroxybenzylidene)cycloheptanone by using the interfacial polycondensation technique. The resulting polyesters were characterized by elemental and spectral analyses. All the synthesized polymers readily dissolved at room temperature in dimethylsulfoxide. The thermal properties of the polymers were evaluated and correlated to their structural units by TGA and DSC measurements. X-ray analysis of polymers showed that all the polyesters are amorphous. Moreover, the morphology of a new high performance polyester, poly[oxycarbonyl-2,7-thianthrene-5,5′,10,10′-tetraox-idecarbonzeoxyl(2-methoxy-p-phenylene)methylidyne(2-oxo-1,3-cyclohexanediylidenemethylidyne)methylidene(3-methoxy-p-phenylene)], has been investigated by scanning electron microscopy.     

Arylidene Polymers. XVII. Cyclization of Aromatic Poly[dibenzylidenecyclopentanone-Hydrazide] as a Route to Polyheterocyclic 1,3,4-Oxadiazole and 1,2,4-Triazole

A new interesting class of thermal stable arylidene polymers containing 1,3,4-oxadiazole and 1,2,4-triazole moieties in the main chain have been synthesized from aromatic polyhydrazide I. Cyclization of I at 250°C in the absence of solvent was found to be the best pathway for the inclusion of the 1,3,4-oxadiazole moiety in the main chain. Heating of I with aniline, cyclohexyl amine, or 3-amino pyridine at 180°C for 30 h gave the corresponding 1,2,4-triazole polymers III. The introducing effect of different aromatic, cycloalkyl, and heterocyclic amines in III_a-c and IV_a-c on thermal stability behavior was studied by TGA analysis. Moreover, all the polymers were characterized by elemental and spectral analyses, solubility, and viscometry measurements. X-ray diffractograms of the synthesized polymers showed they had less crystallinity than the polyhydrazide precursors.