Calorimetric and FTIR study of selected aliphatic octanols
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Isobaric heat capacities of ten selected aliphatic octanols (3-octanol, CAS RN: 589-98-0; 2,2,4-trimethyl-3-pentanol, CAS RN: 5162-48-1; 2,2-dimethyl-3-hexanol, CAS RN: 4209-90-9; 2,3-dimethyl-3-hexanol, CAS RN: 4166-46-5; 2,4-dimethyl-3-hexanol, CAS RN: 13432-25-2; 2,5-dimethyl-3-hexanol, CAS RN: 19550-07-3; 3,5-dimethyl-3-hexanol, CAS RN: 4209-91-0; 4-ethyl-3-hexanol, CAS RN: 19780-44-0; 3-methyl-4-heptanol, CAS RN: 1838-73-9; 4-methyl-4-heptanol, CAS RN: 598-01-6) were measured with a Tian–Calvet calorimeter in the temperature range from 257 to 358 K; this temperature range was extended up to 423 K with a heat-flux DSC. For all studied compounds, a maximum on temperature dependence of heat capacity was observed; this feature was corroborated by FTIR spectroscopy performed from 303 K to a maximum of 463 K. Such maxima are related to disintegration of oligomers kept together by hydrogen bonds. The role of steric hindrance on hydrogen bonding is discussed. It is apparent that temperature of maxima is very sensitive to steric hindrance; however, further effort is required for full understanding of hydrogen bonding in aliphatic octanols.
KeywordsAliphatic octanols Heat capacity Liquid phase Temperature correlation Hydrogen bonding IR spectroscopy
Paulo B. P. Serra acknowledges financial support from specific university research (MSMT No. 20-SVV/2017). The authors acknowledge financial support from the Czech Science Foundation (GACR No. 17-03875S).
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