Heats of combustion of four dialkylethers

Abstract

The heats of combustion in oxygen at 25°C of liquid di-n-butylether, di-sec-butylether, dipropylether and di-iso-propylether were measured using conventional bomb calorimetry. The standard heats of formation of the ethers were derived from the measured combustion heats (values in kcal/mole), viz., AH; (nBu20, Ziq) = -90-34f0-24 ; AH? (nPr20, Ziq) = -78-59f0.21 ; AH; (sBuaO, Ziq) = -95.98 +Ow27 ; AH; (iPr20, Ziq) = -884.01 f0.34.Pilcher and co-workers,l-3 using the flame calorimetric technique, have measured the heats of combustion of a number of low-boiling ethers and oxygen-ring compounds. The flame calorimeter is well-suited to studies on volatile compounds (b.p. <ca. 80"C), but for higher boiling ethers the bomb calorimeter becomes necessary. In the present studies, conventional '' static " bomb calorimetry was applied to measure the heats of combustion at 25°C of di-n-butylether, di-sec-butylether, di-n-propylether and di-iso-propylether. The heats of formation derived from these measurements correlate well with those found by Pilcher for the lower members of the series of dialkylethers. EXPERIMENTAL PREPARATION OF coMPoums.-Di-n-butyl ether was prepared from n-butanol by dehydration with concentrated sulphuric acid, as described by Vogel.4 The product was

Heats of Formation of Medium-Sized Organic Compounds from Contemporary Electronic Structure Methods

“…Second, only small organic and inorganic molecules for which accurate formation enthalpies are known have been used to equilibrate the reactions (i.e., were used as A, B, and D in eq ), in particular acetylene, ethylene, ethane, CO, methane, H 2 , H 2 O, H 2 S, HCN, N 2 , and NH 3 . We expect under these conditions that the possible cancellations of errors are minimal, and better insights into the ability of the electronic structure theory methods to provide accurate reaction enthalpies can be gained. …”

Photochemical Valence Isomerization to High Energy Products—Bicyclobutanes and Oxabicyclobutanes†

“…Using ref. (85) for diisopropyl ether, ref. (79) for both cis ‐ and trans‐ 1,2‐dimethylcyclopropanes, a consensus of refs.…”

“…The more stable are the carbocations, [R] + and [R’] + , the more stable is the derived ether. This is generally seen as the groups R and R’ traverse methyl, primary, secondary and tertiary substitution patterns (85). We recognize the carbon backbone in oxabicyclobutane to contain a cyclopropyl moiety.…”

Thermochemistry of Heteroatomic Compounds: Analysis and Calculation of Thermodynamic Functions of Organic Compounds of V-VII Groups of Mendeleev′s Periodic Table

“…3915.0 ±19.6 367.8 ±1.8 35.7 [31] 4033.1 [32] ±0.79 328.8 [32] ±0.88 293.0 [32] ±2.0 323.9 [33] 396.3 ±2.0 221.6 [33] XXVII Di-iso-propyl ether, i-C6H14O, 36…”

“…318.0 [32] ±3.0 304.6 [33] 377.0 ±1.9 216.1 [33] XXVIII Di-n-Butyl ether, n-C8H18O, 48 45.0 [31] 5342.6 [32] ±0.92 378.0 [32] ±1.0 334.0 [32] ±2.0 278.2 [34] XXIX Di-sec-butyl ether, s-C8H18O, 48 40.6 [9] ±1.2 5319.0 [9] ±1.0 401.5 [9] ±1.2 360.9 [9] ±1.7…”