Calculating Heat of Formation Values of Energetic Compounds: A Comparative Study
Table 1
Comparison of experimental gas-phase heat of formation values with values calculated using several theoretical approaches.
Compound name
Experimental
(kcal/mol)
T1
(kcal/mol)
DFT Atomic and Group contribution
(kcal/mol)
DFT Isodesmic
(kcal/mol)
Group Additivity
(kcal/mol)
PM7
(kcal/mol)
RM1
(kcal/mol)
Nitromethane
−19.3 (−17.09)
Tetranitromethane
19.7 (21.10)
—
Azidotrinitromethane
84.2 (85.32)
81.6
DMNO (N-methyl-N-nitromethanamine)
−1.2
1-Azido-1,1-dinitroethane
60.4 (62.86)
61.3
Hexanitroethane
42.8 (29.18)
—
Nitroglycerin
−66.71
TTT
94.3
—
RDX (cyclotrimethylene-trinitramine)
45.8 (45.79)
—
1,4-Dinitrosopiperazine
46.4
36.8
1,4-Dinitropiperazine
13.9 (15.46)
11.2
N-Nitro-bis-2,2,2-trinitroethylamine
21.42
—
Nitrobenzene
16.38 (15.68)
16.1
2-Nitrophenol
−31.62
3-Nitrophenol
−26.12
4-Nitrophenol
−27.41
m-Nitroaniline
14.9
17.1
p-Nitroaniline
13.2
17.1
Azidobenzene
93.0 (99.19)
97.4
1-Azido-4-nitrobenzene
93.1 (94.17)
93.7
N-Nitrobis-2,2-dinitropropylamine (DNPN)
−31.7
—
PNT (1-methyl-4-nitrobenzene)
7.38
8.1
2,4-DNT (1-methyl-2,4-dinitrobenzene)
7.93
4.4
Azidomethylbenzene
99.5 (96.80)
96.8
3-Azido-3-ethylpentane
40.6 (31.55)
32.9
TNT (trinitrotoluene)
5.75 (12.3)
0.8
2,2-Dinitroadamantane
−36.88 (−42.78)
−35.4
1-Azidoadamantane
51.6 (43.74)
48.0
2-Azido-2-phenylpropane
87.4 (79.59)
79.8
HNS
56.98
35.8
Methyl nitrite
−15.64
Methyl nitrate
−29.2
Dinitromethane
−14.1 (−9.20)
—
Ethyl nitrite
−25.9
Ethyl nitrate
−37.0
Propyl nitrite
−28.4
2-Methyl-2-nitropropane
−42.32 (−41.90)
n-Butyl nitrite
−34.8
t-Butyl nitrite
−41.0
3,4-Furazandimethanol dinitrate
2.6
—
1-Nitropiperidine
−10.6 (−8.87)
Nitrosobenzene
48.1
—
Nitromethylbenzene
7.34
7.6
Dinitromethylbenzene
8.3 (14.2)
12.1
1.3-Dimethyl-2-nitrobenzene
2.1
0.2
HNS = 1,1′-(1,2-ethenediyl)bis2,4,6-trinitrobenzene; TTT = hexahydro-1,3,5-trinitroso-1,3,5-triazine. Values from Byrd and Rice [6, 7]. Values in parentheses are those that have been substituted for corresponding values in the original reference set and are used in the alternative experimental reference set. See text for details and explanation. Most of values in the DFT isodesmic column were calculated using isodesmic reactions. However some values were calculated using isogyric or other balanced equations. Values calculated using CHETAH 8.0.
