Enthalpies of Combustion and Formation of Histidine Stereoisomers

Table 2

Enthalpies of combustion and formation in solid state of isomeric histidines.

Isomeric histidines	(kJ·mol^−1)	(kJ·mol^−1)	(kJ·mol^−1) (this work)^a	(kJ·mol^−1) (literature)	(kJ·mol^−1) (calculated)^b
L-histidine	3196.2 ± 2.4	3195.6 ± 2.4	451.7 ± 3.4	441.8 ± 2.6 [3]; 466.7 ± 2.8 [4]	450.68
D-histidine	3199.2 ± 2.3	3198.6 ± 2.3	448.7 ± 3.3
DL-histidine	3196.4 ± 2.3	3195.8 ± 2.3	451.5 ± 3.3

^aUncertainty included the uncertainties of the enthalpies of formation of the reaction products H₂O and CO₂. ^bEstimated value by means of the group additivity method, with parameters recommended by Domalski and Hearing [14].