Thermal decomposition of .beta.-hydroxy ketones

Yates, Brian L.; Quíjano, Jairo

doi:10.1021/jo01261a005

Cited by 19 publications

(22 citation statements)

References 3 publications

(4 reference statements)

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“…Further kinetic studies on the thermal decomposition of two other Phydroxy ketones, i.e., 4-hydroxy-3-methyl-2-pentanone and 4-hydroxy-2-pentanone, in xylene solutions [2] was aimed at examining the influence of substituted methyl group on the mechanism and velocity. The results obtained from these reactions, in xylene solutions, suggested a n agreement with the mechanism proposed for the reaction in the gas phase as described above (eq.…”

Section: O Hmentioning

confidence: 99%

The retro‐aldol mechanism in the pyrolysis kinetics of primary, secondary, and tertiary β‐hydroxy ketones in the gas phase

Rotinov

Chuchani

Machado

et al. 1992

Int J of Chemical Kinetics

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The pyrolysis kinetics of primary, secondary, and tertiary p-hydroxy ketones have been studied in static seasoned vessels over the pressure range of 21-152 torr and the temperature range of 190"-260°C. These eliminations are homogeneous, unimolecular, and follow a first-order rate law. The rate coefficients are expressed by the following equations: for l-hydroxy-3-butanone, log k l ( s -' ) = (12.18 2 0.39) -(150.0 ? 3.9) k J mol-' (2.303RT)-'; for 4-hydroxy-2-pentanone, log k l ( s -' ) = (11.64 ? 0.28) -(142.1 ? 2.7) k J mol-' (2.303RT)-'; and for 4-hydroxy-4-methyl-2-pentanone, log k 1 k -l ) = (11.36 ? 0.52) -(133.4 -t 4.9) k J mol-' (2.303RT)-'. The acid nature of the hydroxyl hydrogen is not determinant in rate enhancement, but important in assistance during elimination. However, methyl substitution at the hydroxyl carbon causes a small but significant increase in rates and, thus, appears to be the limiting factor in a retroaldol type of mechanism in these decompositions. 0

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Section: O Hmentioning

confidence: 99%

The retro‐aldol mechanism in the pyrolysis kinetics of primary, secondary, and tertiary β‐hydroxy ketones in the gas phase

Rotinov

Chuchani

Machado

et al. 1992

Int J of Chemical Kinetics

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“…Table 3 gives the molar energies and enthalpies of combustion derived from the combustion reaction of 3-hydroxypropanenitrile in the liquid state at T = 298. 15 …”

Section: Resultsmentioning

confidence: 99%

“…Experimental and/or theoretical studies of the thermolysis reaction of b-hydroxy derivatives [4][5][6][7][8][9][10][11][12][13][14][15], and specially b-hydroxynitriles [5,9] have been carried out for some of us. In a recent work [16], we have published the results obtained from a calorimetric and computational study of the thermochemistry of 3-buten-1-ol and 3-butyn-1-ol concluding that the weak intramolecular hydrogen bond from the OH hydrogen to the p-bond charge cloud that exists in both compounds has not significant influence on the enthalpy of formation of these species.…”

Section: Introductionmentioning

confidence: 99%

Experimental and computational thermochemical study of 3-hydroxypropanenitrile

Roux¹,

Notario²,

Vélez³

et al. 2007

The Journal of Chemical Thermodynamics

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“…It has previously been observed that [6] in m-xylene solutions at 553 K, β-hydroxyketone and 4-hydroxy-4-methyl-2-pentanone pyrolyze 134 times more rapidly than do the analogously substituted β-hydroxy ester: ethyl-3-hydroxy-3-methylbutanoate pyrolyzes 2170 times more rapidly than do methyl-3-hydroxy-3-methylbutanoate. The proposed mechanism is consistent with the greater difficulty in the formation of enol from esters than from ketones [11] (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Thermal decomposition of methyl β‐hydroxyesters in m‐xylene solution

Zapata

Gaviria

Quíjano

2006

Int J of Chemical Kinetics

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The products and kinetics of the thermal decomposition of several methyl-β-hydroxyesters in m-xylene solution have been studied. It has been shown that all β-hydroxyesters studied pyrolyze to form a mixture of methyl acetate and the corresponding aldehyde or ketone and that the decomposition follows first-order kinetics and appears to be homogeneous and unimolecular. The rate pyrolysis of methyl-3-hydroxypropanoate, methyl-3-hydroxybutanoate, and methyl-3-hydroxy-3-methylbutanoate has been measured between 250 and 320 • C. The relative rates of primary, secondary, and tertiary alcohols at 553 K are 1.0, 8.5 and 54.1, respectively. The absence of large substituent effects indicates that little charge separation occurs during the breaking of carbon-carbon single bond. The activation entropy is compatible with a semipolar six-membered cyclic transition state postulated for other β-hydroxy compounds. C 2006 Wiley Periodicals, Inc. Int J Chem Kinet 39: 92-96, 2007

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Thermal decomposition of .beta.-hydroxy ketones

Cited by 19 publications

References 3 publications

The retro‐aldol mechanism in the pyrolysis kinetics of primary, secondary, and tertiary β‐hydroxy ketones in the gas phase

The retro‐aldol mechanism in the pyrolysis kinetics of primary, secondary, and tertiary β‐hydroxy ketones in the gas phase

Experimental and computational thermochemical study of 3-hydroxypropanenitrile

Thermal decomposition of methyl β‐hydroxyesters in m‐xylene solution

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