Propanal, 2-methyl-

Formula: C₄H₈O
Molecular weight: 72.1057
IUPAC Standard InChI: InChI=1S/C4H8O/c1-4(2)3-5/h3-4H,1-2H3
IUPAC Standard InChIKey: AMIMRNSIRUDHCM-UHFFFAOYSA-N
CAS Registry Number: 78-84-2
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript.
Other names: Isobutyraldehyde; α-Methylpropionaldehyde; Isobutanal; Isopropylaldehyde; Isopropylformaldehyde; 2-Methylpropanal; 2-Methylpropionaldehyde; iso-C3H7CHO; Isobutylaldehyde; Isobutyric aldehyde; 2-Methyl-1-propanal; Isobutyraldehyd; Propionaldehyde, 2-methyl-; Valine aldehyde; Isobutaldehyde; Isobutyryl aldehyde; Methyl propanal; NCI-C60968; UN 2045; Isobutyral; NSC 6739; 2-methylpropanal (isobutanal)
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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	-215.8 ± 1.5	kJ/mol	Cm	Wiberg, Crocker, et al., 1991	ALS
Δ_fH°_gas	-216.4	kJ/mol	N/A	Gubareva and Gerasimov, 1990	Value computed using Δ_fH_liquid° value of -247.9±0.7 kj/mol from Gubareva and Gerasimov, 1990 and Δ_vapH° value of 31.5 kj/mol from Connett, 1975.; DRB
Δ_fH°_gas	-215.7 ± 1.3	kJ/mol	Eqk	Connett, 1975	Heat of dehydrogenation; ALS
Δ_fH°_gas	-218.	kJ/mol	Ccb	Tjebbes, 1962	ALS

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	-247.3 ± 0.92	kJ/mol	Cm	Wiberg, Crocker, et al., 1991
Δ_fH°_liquid	-247.9 ± 0.7	kJ/mol	Ccb	Gubareva and Gerasimov, 1990
Δ_fH°_liquid	-247.2 ± 1.3	kJ/mol	Eqk	Connett, 1975	Heat of dehydrogenation
Δ_fH°_liquid	-250.2 ± 0.75	kJ/mol	Ccb	Tjebbes, 1962
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-2469.4 ± 0.7	kJ/mol	Ccb	Gubareva and Gerasimov, 1990	Corresponding Δ_fHº_liquid = -248.0 kJ/mol (simple calculation by NIST; no Washburn corrections)
Δ_cH°_liquid	-2467.2 ± 0.75	kJ/mol	Ccb	Tjebbes, 1962	Corresponding Δ_fHº_liquid = -250.2 kJ/mol (simple calculation by NIST; no Washburn corrections)

Phase change data

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Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
DRB - Donald R. Burgess, Jr.
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity	Value	Units	Method	Reference	Comment
T_boil	336. ± 2.	K	AVG	N/A	Average of 24 out of 27 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_fus	201.00	K	N/A	Tjebbes, 1962, 2	Uncertainty assigned by TRC = 0.5 K; TRC
T_fus	207.3	K	N/A	Anonymous, 1958	Uncertainty assigned by TRC = 2. K; TRC
T_fus	145.	K	N/A	Cook, 1952	Uncertainty assigned by TRC = 3. K; TRC
T_fus	207.3	K	N/A	Timmermans, 1922	Uncertainty assigned by TRC = 0.4 K; TRC
Quantity	Value	Units	Method	Reference	Comment
Δ_vapH°	32.0 ± 0.9	kJ/mol	AVG	N/A	Average of 7 values; Individual data points

Enthalpy of vaporization

Δ_vapH (kJ/mol)	Temperature (K)	Method	Reference	Comment
31.4	318.	N/A	Eng and Sandler, 1984	Based on data from 313. to 324. K.; AC
31.8	324.	N/A	Brazhnikov, Peshchenko, et al., 1976	Based on data from 309. to 337. K.; AC
33.4	340.	EB	Wojtasinski, 1963	Based on data from 333. to 347. K.; AC

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
P = vapor pressure (bar)
T = temperature (K)

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Temperature (K)	A	B	C	Reference	Comment
286.08 to 336.00	3.87395	1060.141	-63.196	Seprakova, Paulech, et al., 1959	Coefficents calculated by NIST from author's data.

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:

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

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

C₄H₇O^- + = Propanal, 2-methyl-

By formula: C₄H₇O^- + H⁺ = C₄H₈O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1535. ± 13.	kJ/mol	D-EA	Alconcel, Deyerl, et al., 2001	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1504. ± 13.	kJ/mol	H-TS	Alconcel, Deyerl, et al., 2001	gas phase; B

+ Propanal, 2-methyl- =

By formula: H₂ + C₄H₈O = C₄H₁₀O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-87.4 ± 0.3	kJ/mol	Cm	Wiberg, Crocker, et al., 1991	liquid phase; ALS
Δ_rH°	-68.1 ± 0.9	kJ/mol	Eqk	Connett, 1975	gas phase; Heat of dehydrogenation; ALS

(CAS Reg. No. 35730-34-8 • 4294967295 Propanal, 2-methyl- ) + = CAS Reg. No. 35730-34-8

By formula: (CAS Reg. No. 35730-34-8 • 4294967295C₄H₈O) + C₄H₈O = CAS Reg. No. 35730-34-8

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	176. ± 9.2	kJ/mol	N/A	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B

= + Propanal, 2-methyl-

By formula: C₄H₁₀O = H₂ + C₄H₈O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	68.1 ± 0.9	kJ/mol	Eqk	Connett, 1975	gas phase; Heat of dehydrogenation; ALS

+ = 2 + Propanal, 2-methyl-

By formula: C₆H₁₄O₂ + H₂O = 2CH₄O + C₄H₈O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	36.39 ± 0.067	kJ/mol	Eqk	Wiberg and Squires, 1981	liquid phase; ALS

+ Propanal, 2-methyl- =

By formula: H₂O + C₄H₈O = C₄H₁₀O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-23.	kJ/mol	Eqk	Green and Hine, 1973	liquid phase; ALS

3 Propanal, 2-methyl- =

By formula: 3C₄H₈O = C₁₂H₂₄O₃

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-28.47	kJ/mol	Eqk	Ogorodnikov, Katsnel'son, et al., 1990	liquid phase; PMR; ALS

= Propanal, 2-methyl-

By formula: C₄H₈O = C₄H₈O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-86.19	kJ/mol	Kin	Farberov, Bondarenko, et al., 1984	liquid phase; ALS

References

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

Wiberg, Crocker, et al., 1991
Wiberg, K.B.; Crocker, L.S.; Morgan, K.M., Thermochemical studies of carbonyl compounds. 5. Enthalpies of reduction of carbonyl groups, J. Am. Chem. Soc., 1991, 113, 3447-3450. [all data]

Gubareva and Gerasimov, 1990
Gubareva, A.I.; Gerasimov, P.A., Physicochemical properties of isobutyraldehyde, J. Appl. Chem. USSR, 1990, 63, 844-846. [all data]

Connett, 1975
Connett, J.E., Chemical equilibria 6. Measurement of equilibrium constants for the dehydrogenation of 2-methylpropan-1-ol by a vapour-flow technique, J. Chem. Thermodyn., 1975, 7, 1159-1162. [all data]

Tjebbes, 1962
Tjebbes, J., Heats of combustion of propanal and 2-methyl propanal, Acta Chem. Scand., 1962, 16, 953-857. [all data]

Tjebbes, 1962, 2
Tjebbes, J., Acta Chem. Scand., 1962, 16, 953. [all data]

Anonymous, 1958
Anonymous, R., , Am. Pet. Inst. Res. Proj. 45, Ohio State Univ., 1958. [all data]

Cook, 1952
Cook, N.C., , Unpublished, Final Rep. Stand. Proj. on Oxygenated Compounds, Penn. State Univ., College Park, PA, 1952. [all data]

Timmermans, 1922
Timmermans, J., Investigation of the Freezing Point of Organic Substances VII, Bull. Soc. Chim. Belg., 1922, 31, 389. [all data]

Eng and Sandler, 1984
Eng, Robert; Sandler, Stanley I., Vapor-liquid equilibria for three aldehyde/hydrocarbon mixtures, J. Chem. Eng. Data, 1984, 29, 2, 156-161, https://doi.org/10.1021/je00036a017 . [all data]

Brazhnikov, Peshchenko, et al., 1976
Brazhnikov, M.M.; Peshchenko, A.D.; Ral'ko, O.V., Zh. Prikl. Khim. (Leningrad), 1976, 49, 1041. [all data]

Wojtasinski, 1963
Wojtasinski, Jerome G., Measurement of Total Pressures for Determining Liquid-Vapor Equilibrium Relations of the Binary System Isobutyraldehyde n-Butyraldehyde., J. Chem. Eng. Data, 1963, 8, 3, 381-385, https://doi.org/10.1021/je60018a028 . [all data]

Seprakova, Paulech, et al., 1959
Seprakova, M.; Paulech, J.; Dykyj, J., Dampfdruck der Butyraldehyde, Chem. Zvesti, 1959, 13, 313-316. [all data]

Alconcel, Deyerl, et al., 2001
Alconcel, L.S.; Deyerl, H.J.; Continetti, R.E., Effects of alkyl substitution on the energetics of enolate anions and radicals, J. Am. Chem. Soc., 2001, 123, 50, 12675-12681, https://doi.org/10.1021/ja0120431 . [all data]

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Wiberg and Squires, 1981
Wiberg, K.B.; Squires, R.R., Thermochemical studies of carbonyl reactions. 2. Steric effects in acetal and ketal hydrolysis, J. Am. Chem. Soc., 1981, 103, 4473-4478. [all data]

Green and Hine, 1973
Green, L.R.; Hine, J., Isobutyraldehyde. The kinetics of acid- and base-catalyzed equilibrations in water, J. Org. Chem., 1973, 38, 2801-28. [all data]

Ogorodnikov, Katsnel'son, et al., 1990
Ogorodnikov, A.L.; Katsnel'son, M.G.; Pinson, V.V.; Levin, Yu.V., Study of thermodynamic characteristics of a butyraldehyde-cyclic trimer system, Zh. Prikl. Khim. (Leningrad), 1990, 63, 1340-1343. [all data]

Farberov, Bondarenko, et al., 1984
Farberov, M.I.; Bondarenko, A.V.; Tsilyurik, T.V.; Srednev, S.S.; Shutova, I.A., Epoxidation of isobutene with organic hydroperoxides, and certain syntheses on this basis, J. Anal. Chem. USSR, 1984, 57, 1915-1919. [all data]

Notes

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Symbols used in this document:

T_boil	Boiling point
T_fus	Fusion (melting) point
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
Δ_vapH	Enthalpy of vaporization
Δ_vapH°	Enthalpy of vaporization at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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