Trimethylaluminum

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Gas phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: José A. Martinho Simões

Quantity Value Units Method Reference Comment
Δfgas-86.5 ± 4.8kJ/molReviewMartinho SimõesSelected data. The enthalpy of formation relies on -1891.3 ± 1.9 kJ/mol for the enthalpy of formation of Al(OOCMe)3(cr) and on 0.9 ± 0.2 kJ/mol for the enthalpy of solution of MeCOOH(l) in toluene Mortimer and Sellers, 1963. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.
Δfgas-57.0 ± 9.7kJ/molReviewMartinho SimõesLiquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.
Δfgas-88.7kJ/molReviewMartinho SimõesThe enthalpy of formation was quoted from Smith, 1974 and relies on experimental data in Tröber and Stricker, 1966. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.

Condensed phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
MS - José A. Martinho Simões
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Δfliquid-149.7 ± 4.5kJ/molReviewMartinho SimõesSelected data. The enthalpy of formation relies on -1891.3 ± 1.9 kJ/mol for the enthalpy of formation of Al(OOCMe)3(cr) and on 0.9 ± 0.2 kJ/mol for the enthalpy of solution of MeCOOH(l) in toluene Mortimer and Sellers, 1963. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS
Δfliquid-120.2 ± 9.6kJ/molReviewMartinho SimõesLiquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS
Δfliquid-151.9kJ/molCC-SBSmith, 1974Value corrected based on a set of ancillary data by J.A. Martinho Simões; The enthalpy of formation was quoted from Smith, 1974 and relies on experimental data in Tröber and Stricker, 1966. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS
Quantity Value Units Method Reference Comment
Δcliquid-3184.4 ± 9.6kJ/molCC-SBLong and Norrish, 1949Please also see Cox and Pilcher, 1970. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS
Quantity Value Units Method Reference Comment
liquid209.41J/mol*KN/AMcCullough, Messerly, et al., 1963DH

Constant pressure heat capacity of liquid

Cp,liquid (J/mol*K) Temperature (K) Reference Comment
155.60298.15McCullough, Messerly, et al., 1963T = 10 to 380 K.; DH

Phase change data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
MS - José A. Martinho Simões
AC - William E. Acree, Jr., James S. Chickos
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Ttriple288.43KN/AMcCullough, Messerly, et al., 1963, 2Uncertainty assigned by TRC = 0.02 K; TRC
Quantity Value Units Method Reference Comment
Δvap63.2 ± 1.7kJ/molRSCMcCullough, Messerly, et al., 1963, 2MS

Enthalpy of vaporization

ΔvapH (kJ/mol) Temperature (K) Reference Comment
43.0288. to 293.Fulem, Ruzicka, et al., 2003AC
39.8351.McCullough, Messerly, et al., 1963Based on data from 336. to 400. 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
336.96 to 400.274.679841724.231-31.398McCullough, Messerly, et al., 1963Coefficents calculated by NIST from author's data.

Enthalpy of sublimation

ΔsubH (kJ/mol) Temperature (K) Reference Comment
60.1243. to 285.Fulem, Ruzicka, et al., 2003AC

Enthalpy of fusion

ΔfusH (kJ/mol) Temperature (K) Reference Comment
8.7906288.43McCullough, Messerly, et al., 1963DH
8.79288.4Domalski and Hearing, 1996AC

Entropy of fusion

ΔfusS (J/mol*K) Temperature (K) Reference Comment
30.48288.43McCullough, Messerly, et al., 1963DH

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 compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
B - John E. Bartmess
MS - José A. Martinho Simões

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

Hydrogen anion + Trimethylaluminum = (Hydrogen anion • Trimethylaluminum)

By formula: H- + C3H9Al = (H- • C3H9Al)

Quantity Value Units Method Reference Comment
Δr>354.8 ± 2.1kJ/molIMRBden Berg, Ingemann, et al., 1992gas phase; Hydride affinity > (CF3)2CO. Computations indicate HOF(A-) ca. -46 kcal/mol, dHaff ca. 74 kcal/mol; B

C6H18Al2 (l) = 2Trimethylaluminum (l)

By formula: C6H18Al2 (l) = 2C3H9Al (l)

Quantity Value Units Method Reference Comment
Δr81.2 ± 1.3kJ/molEqSSmith, 1972MS

Gas phase ion energetics data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Ionization energy determinations

IE (eV) Method Reference Comment
9.09 ± 0.26EIWinters and Kiser, 1967RDSH
9.76PEBarker, Lappert, et al., 1975Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
Al+14.6 ± 0.2?EIWinters and Kiser, 1967RDSH
CH3Al+13.9 ± 0.3?EIWinters and Kiser, 1967RDSH
C2H6Al+10.1 ± 0.3CH3EIWinters and Kiser, 1967RDSH

References

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

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Martinho Simões
Martinho Simões, J.A., Private communication (see http://webbook.nist.gov/chemistry/om/). [all data]

Mortimer and Sellers, 1963
Mortimer, C.T.; Sellers, P., J. Chem. Soc., 1963, 1978.. [all data]

Smith, 1972
Smith, M.B., J. Organometal. Chem., 1972, 46, 31. [all data]

Smith, 1974
Smith, M.B., J. Organometal. Chem., 1974, 76, 171. [all data]

Tröber and Stricker, 1966
Tröber, A.; Stricker, C., Wiss Z. Tech. Hochsch. Chem. "Carl Schlorlemmer" Leuna-Merseburg, 1966, 8, 34. [all data]

Long and Norrish, 1949
Long, L.H.; Norrish, R.G.W., Phil. Trans. Roy. Soc. (London), 1949, A241, 587. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds in Academic Press, New York, 1970. [all data]

McCullough, Messerly, et al., 1963
McCullough, J.P.; Messerly, J.F.; Moore, R.T.; Todd, S.S., Trimethylaluminum: thermodynamic functions in the solid and liquid states, 0-380°K, vapor pressure, heat of vaporization, and entropy in the ideal gas state, J. Phys. Chem., 1963, 67, 677-679. [all data]

McCullough, Messerly, et al., 1963, 2
McCullough, J.P.; Messerly, J.F.; Moore, R.T.; Todd, S.S., J. Phys. Chem., 1963, 67, 677. [all data]

Fulem, Ruzicka, et al., 2003
Fulem, M.; Ruzicka, K.; Ruzicka, V.; Hulicius, E.; Simecek, T.; Melichar, K.; Pangrác, J.; Rushworth, S.A.; Smith, L.M., Vapor pressure of metal organic precursors, Journal of Crystal Growth, 2003, 248, 99-107, https://doi.org/10.1016/S0022-0248(02)01840-7 . [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

den Berg, Ingemann, et al., 1992
den Berg, K.J. van; Ingemann, S.; Nibbering, N.M.M., Gas Phase Reactions of Negative Ions with Trimethylaluminum: Formation and Reactivity of the Me3AlH- Ion., Org. Mass Spectrom., 1992, 27, 4, 523, https://doi.org/10.1002/oms.1210270427 . [all data]

Winters and Kiser, 1967
Winters, R.E.; Kiser, R.W., Ionization and fragmentation of dimethylzinc, trimethylaluminum, and trimethylantimony, J. Organometal. Chem., 1967, 10, 7. [all data]

Barker, Lappert, et al., 1975
Barker, G.K.; Lappert, M.F.; Pedley, J.B.; Sharp, G.J.; Westwood, N.P.C., Bonding studies of boron and the group 3-5 elements. Part XV. He(I) photoelectron spectra of monomeric group 3 tri-halide, trimethyl, and mixed halogenomethyl species, J. Chem. Soc. Dalton Trans., 1975, 1765. [all data]


Notes

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