Alcohol, energy content

The anaerobic digestion of fatty acids, alcohols and organic compounds is accomplished by a syntrophy between H2-producing and H2-consuming methanogenic archaea [6] that favors the better use of the energy content of primary substrates [7]. 

With water-alcohol, both molecules with an OH dipole, the cause of the positive heat of mixing is to be found elsewhere. In view of the strong volume contraction, which occurs on mixing, the packing in water-alcohol mixtures is appreciably denser than in water and alcohol themselves. In particular water has an open, partly ordered structure (p. 380). The introduction of alcohol molecules disturbs this structure and the dense packing itself gives rise to a low energy content the formation of definite alcohol hydrates does not occur here. 

Although pressure arises naturally from mechanics, the concept of temperature is more abstract. To the nonscientist, temperature is a measure of hotness or coldness and a.s such is not carefully defined, but rather is a quantity related to such things as physical comfort, cooking conditions, or the le el of mercury or colored alcohol in a thermometer. To the scientist, temperature is a precisely defined quantity, deeply rooted in the concept of equilibrium and related to the energy content of a substance. 

Carboxylic acids and phenols are relatively stronger acids than alcohols both in gas phase and in solution. The difference in the gas-phase acidities is usually attributed to a low-energy content of the carboxylate anions, which would be stabilized by the resonance effect, as shown in Figure 7.1... 

Room temperatme, in air-equilibrated acetonitrile unless otherwise indicated, PFg salts Lowest energy band(s) with e > 1000 Highest energy peak maximiun In square brackets, values in degassed solvent Energy content of the luminescent level estimated from fits of the luminescence profile at room temperature or from the luminescence band maximum at 77 K Alcoholic solvent... 

It was mentioned earlier that over 90 percent of the heat transfer in the rotary kiln is by radiation. It is not surprising, therefore, that natural gas, despite its high energy content (about 44-48 MJ/kg), does not sustain heat as effectively as coal (with 23-28 MJ/kg) in kilns. Most of the constituents in liquid waste fuels used in kilns are solvents and alcohols that contain a low carbon-hydrogen ratio. This therefore produces barely visible flames which have low radiant energy emission. It is not uncommon for the kiln operator to face a situation where the measured energy content of such fuels would be high but cannot produce a quality product even when it is possible to increase fuel flow rate within compliance limits. 

The calculated reaction coordinate reveals higher stability and lower energy of the transition state alkyl borane on the prim-C-atom than on the scc-C-atom, although the energy content of the product prim-alcohol is higher than that of the sec-alcohol. The whole process is a typical example of a kinetically controlled reaction. 

---