US EPA

8442858 

Journal Article 

Thermodynamics of binary mixtures containing alkynes. II - Excess enthalpies of binary mixtures of 1-hexyne and 3-hexyne with carbon tetrachloride, dipropyl ether, and triethylamine at 298.15 K 

Wilhelm, E; Inglese, A; Grolier, JPE; Kehiaian, HV 

1978 

1 

Monatshefte für Chemie / Chemical Monthly
ISSN: 0026-9247
EISSN: 1434-4475 

Springer-Verlag 

109 

2 

435-442 

English 

10.1007/BF00906361 

Molar excess enthalpies HE of 1-hexyne + carbon tetrachloride, + dipropyl ether, + triethylamine, and of 3-hexyne + carbon tetrachloride, + dipropyl ether, + triethylamine at 298.15 K and atmospheric pressure were measured with a Picker-type flow microcalorimeter over the whole concentration range. At equimolar concentration, HE of 3-hexyne + carbon tetrachloride is strongly exothermic (-499 J mol-1), in contrast to HE=+14 J mol-1 for the 1-hexyne system. As expected, for the ether and amine systems inverse behavior is observed: because of the active hydrogen of terminal alkynes the enthalpy of mixing at equimolar concentration is more exothermic with 1-hexyne (-185 J mol-1, dipropyl ether; -300 J mol-1, triethylamine) than with 3-hexyne (-25 J mol-1, dipropyl ether; -92 J mol-1, triethylamine). The curve HE vs. mole fraction is considerably skewed for 3-hexyne (x1) + triethylamine, the minimum being ca. -197 J mol-1 at x1≈0.9. © 1978 Springer-Verlag.