Methyl isocyanide

Formula: C₂H₃N
Molecular weight: 41.0519
IUPAC Standard InChI: InChI=1S/C2H3N/c1-3-2/h1H3
IUPAC Standard InChIKey: ZRKSVHFXTRFQFL-UHFFFAOYSA-N
CAS Registry Number: 593-75-9
Chemical structure:
This structure is also available as a 2d Mol file
Other names: Methane, isocyano-; Isocyanomethane; Methyl isonitrile; CH3NC
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Gas phase thermochemistry data

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Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	163.5 ± 7.2	kJ/mol	Cm	Baghal-Vayjooee, Collister, et al., 1977	Reanalyzed by Pedley, Naylor, et al., 1986, Original value = 172.9 ± 1.0 kJ/mol; Heat of isomerization; ALS
Δ_fH°_gas	142.8	kJ/mol	N/A	Lemoult, 1906	Value computed using Δ_fH_liquid° value of 112.0 kj/mol from Lemoult, 1906 and Δ_vapH° value of 30.8 kj/mol from Baghal-Vayjooee, Collister, et al., 1977.; DRB

Condensed phase thermochemistry data

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Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_liquid	132.7 ± 7.3	kJ/mol	Cm	Baghal-Vayjooee, Collister, et al., 1977	Reanalyzed by Pedley, Naylor, et al., 1986, Original value = 142.0 ± 1.5 kJ/mol; Heat of isomerization
Δ_fH°_liquid	112.	kJ/mol	Ccb	Lemoult, 1906
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1333.	kJ/mol	Ccb	Lemoult and Jungfleisch, 1909
Δ_cH°_liquid	-1333.	kJ/mol	Ccb	Lemoult, 1906

Reaction thermochemistry data

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Data compiled as indicated in comments:
B - John E. Bartmess
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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Individual Reactions

C₂H₂N^- + = Methyl isocyanide

By formula: C₂H₂N^- + H⁺ = C₂H₃N

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1592. ± 8.8	kJ/mol	G+TS	Matimba, Crabbendam, et al., 1992	gas phase; B
Δ_rH°	1567. ± 8.8	kJ/mol	G+TS	Filley, DePuy, et al., 1987	gas phase; Matimba, Crabbendam, et al., 1992 indicate that CN- loss interfered with equilibrium here.; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1561. ± 8.4	kJ/mol	IMRE	Matimba, Crabbendam, et al., 1992	gas phase; B
Δ_rG°	1536. ± 8.4	kJ/mol	IMRE	Filley, DePuy, et al., 1987	gas phase; Matimba, Crabbendam, et al., 1992 indicate that CN- loss interfered with equilibrium here.; B

Methyl isocyanide =

By formula: C₂H₃N = C₂H₃N

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-99.16 ± 0.59	kJ/mol	Cm	Baghal-Vayjooee, Collister, et al., 1977	gas phase; Heat of isomerization; ALS

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Notes

Baghal-Vayjooee, Collister, et al., 1977
Baghal-Vayjooee, M.H.; Collister, J.L.; Pritchard, H.O., The enthalpy of isomerisation of methyl isocyanide, Can. J. Chem., 1977, 55, 2634-2636. [all data]

Pedley, Naylor, et al., 1986
Pedley, J.B.; Naylor, R.D.; Kirby, S.P., Thermochemical Data of Organic Compounds, Chapman and Hall, New York, 1986, 1-792. [all data]

Lemoult, 1906
Lemoult, P., Carbylamines et nitriles., Compt. Rend., 1906, 143, 902-904. [all data]

Lemoult and Jungfleisch, 1909
Lemoult, M.P.; Jungfleisch, M.E., Thermochimie. - Comparaisons entre les nitriles et les carbylamines, Compt. Rend., 1909, 148, 1602-1604. [all data]

Matimba, Crabbendam, et al., 1992
Matimba, H.E.K.; Crabbendam, A.M.; Ingemann, S.; Nibbering, N.M.M., Gas-phase Bimolecular Chemistry of the .-CHNC and .-CHCN Radical Anions, Int. J. Mass Spectrom. Ion Proc., 1992, 114, 1-2, 85, https://doi.org/10.1016/0168-1176(92)85024-T . [all data]

Filley, DePuy, et al., 1987
Filley, J.; DePuy, C.H.; Bierbaum, V.M., Gas-Phase Negative Ion Chemistry of Methyl Isocyanide, J. Am. Chem. Soc., 1987, 109, 20, 5992, https://doi.org/10.1021/ja00254a017 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, References

Symbols used in this document:

Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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