ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Geminal Substituent Effects. VIII. Enthalpies of Formation of AcetalsThe standard enthalpies of combustion ΔHc° (1 or c) of the α-phenyl-substituted acetals (1) and diacetals (2) were measured calorimetrically. The enthalpies of vaporisation or sublimation ΔHvap or ΔHsub of 1-2 were obtained from the temperature function of the vapor pressure measured in a flow system, and the standard enthalpies of formation are obtained thereof: ΔH°f (1 or c) and ΔHf° (g) (in kJ mol-1) for 1a = -308.40 ± 0.52(1), -248.94 ± 0.88; 1b = -343.48 ± 0.72 (1), -288.5 ± 1.5; 1c = -267.4 ± 1.3 (1), -205.3 ± 1.3; 1d = -343.8 ± 2.1 (c), -261.9 ± 2.2; 1e = -397.02 ± 0.86 (c), -311.3 ± 1.2; 1f = -414.52 ± 0.80 (1), -350.68 ± 0.86; 2a = -564.8 ± 2.4 (c), -467.1 ± 2.5; 2b = -547.6 ± 1.6 (c), -414.9 ± 2.7; 2c = -717.1 ± 7.5 (c), -587.0 ± 8.0. The results are combined into values of two strain free group increments CH[20, CPh] = -59.7 and C[20, CPh, C] = -71.3 kJ mol-1; and compared to the aliphatic series of acetals.
Additional Material:
4 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19953370122
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