| Title:  Tolan CAS Registry Number:  501-65-5 CAS Name:  1,1¢-(1,2-Ethynediyl)bisbenzene Additional Names:  diphenylacetylene;  diphenylethyne Molecular Formula:  C14H10 Molecular Weight:  178.23 Percent Composition:  C 94.34%, H 5.66% Line Formula:  C6H5CºCC6H5 Literature References:  Prepd by the oxidation of benzil dihydrazone with mercuric oxide:  Schlenk, Bergmann, Ann. 463, 76 (1928); by dehydrohalogenation of stilbene dibromide:  Söderbäck, Ann. 443, 161 (1925); Smith, Hoehn, J. Am. Chem. Soc. 63, 1180 (1941); Smith, Falkof, Org. Synth. coll. vol. III, 350 (1955).  Improved procedure:  L. F. Fieser, Experiments in Organic Chemistry (Boston, 3rd ed., 1955) p 181. Properties:  Monoclinic, pseudo-rhombic rods or large spears from 95% ethanol.  mp 60-61° (also reported as 62.5°).  bp760 300°; bp19 170°.  Dipole moment 0.3.  Specific heat at 20°:  0.297.  uv max:  216, 221, 269, 272, 279, 288, 297 nm (e 20600, 20300, 23450, 25200, 33000, 23250, 29400).  Insol in water.  Freely sol in ether, hot alcohol. Melting point:  mp 60-61° (also reported as 62.5°) Boiling point:  bp760 300°; bp19 170° Absorption maximum:  uv max:  216, 221, 269, 272, 279, 288, 297 nm (e 20600, 20300, 23450, 25200, 33000, 23250, 29400)  |