Propanol ions, decomposition

As noted after equation 4.17, the procedure to evaluate standard enthalpies of formation from appearance energies is somewhat controversial. When the threshold energies are determined from electron impact experiments, it has been argued that the correction terms (H%9S - Hq)a+ + (77298 - o)b - 6.197 in equation 4.17 should not be included in the calculation [66], Consider, for instance, reactions 4.21, and 4.22 where the ion CH2OH+ was produced from the decomposition of 1-propanol or methanol. 

The physicochemical characterization of the acidity of the doped alumina performed by microcalorimetry, has been complementarized with the catalytic test of 2-propanol decomposition [175], It was found that the modification of y-Al203 surface properties with small amounts of Ca ", Li+, Nd ", NF+, SO/, Zf +ions changed moderately its amphoteric properties. The catalytic test of 2-propanol... 

Similar results were obtained for tert-butyl hydroperoxide and perchloric acid in 2-propanol. Thus, it is evident from the decomposition of hydrogen peroxide into free radicals that both heterolytic and homolytic reactions may be catalyzed by hydrogen ions. Further research is needed to investigate proton catalysis in certain homolytic reactions. 

ZSM-5, acid-catalyzed decomposition of both 2-propanol and 2-propanamine was observed only when the Ga and Fe were present as part of the ZSM-5 framework. Due to the fact that the B sites in H-[B]-ZSM-5 are much more weakly acidic, no reaction was observed for the probe molecules we studied however, with 2-propanamine, a well-defined state corresponding to adsorption at the B sites could still be observed. Finally, these studies give insight into the relative strengths of the sites generated by the incorporation of various trivalent ions into the ZSM-5 framework. 

The possible types of chain mechanisms for peroxodisulphate oxidation have been classified by Wilmarth and Haim according to the dominant initiation and termination steps, and the relative importance of sulphate radical-ions and hydroxyl radicals in the propagation steps. Some of the rate equations corresponding to the different types of mechanisms are the same, so the observation of a particular rate equation does not always permit a unique mechanism to be inferred. In certain cases the nature of the chain initiation step can be deduced from the effect of a free-radical scavenger on the reaction rate. Thus in the oxidation of 2-propanol, the addition of allyl acetate reduces the rate to that observed for the spontaneous decomposition of peroxodisulphate, indicating that the chain initiation step is the same as the rate-determining step of the spontaneous decomposition, viz. the fission of peroxodisulphate into sulphate radical-ions. 

In addition to different bonding characteristics of the reaction intermediate on the different surfaces, at least two other interactions that differ on the different surfaces can be identified. The atomic arrangement of an ideal Zn-polar surface is such that a layer of Zn ions is more outwardly situated than the next layer of 0 ions. Because the exposed ions are Zn ions which are nonpolarizable, this surface is a hard acid (14) Conversely, an ideal 0-polar surface has a layer of 0 ions more outwardly situated than the next layer of Zn ions. These exposed 0 ions make the surface a soft base. The intermediate in 2-propanol decomposition is an eno late ion (13 ). Being a base, it should interact more strongly with a hard acid than a soft base. 

Preliminary results with a manganese-substituted Keggin ion catalyst that has an extremely stable PWi 1039 - backbone (Figure 1), shows some promise with small hydrocarbons(l). This catalyst can be heated to 65 °C for long periods without decomposition. An initial experiment with ethane and t-butyl hydroperoxide in benzene gave 2 turnovers of ethane to ethanol in three hr at 65 °C, while with propane the turnover number was 24 and provided isopropanol and n-propanol in a 5 1 ratio (Table m). 

Br" ions inhibit the oxidation of alcohols if the latter do not contain H202. However, in the presence of H202, 2-propanol oxidation is accelerated by Br" [89], as the latter induces decomposition of H202 leading to free radical formation. The rate of initiation by reaction of Br" with H202 is [89]... 

The relationship of the nitrous acid and nitrosoamide methods of deamination is more tenuous in water since only one example of the i nitrosoamide decomposition in aqueous media has been reported. The decomposition of A -nitroso-A -n-propylbenzamide in dimethyl-formamide-water (60/40 by vol) yielded a propyl benzoate fraction containing 9% of the isopropyl isomer and a propanol fraction con- taining 33% of isopropyl alcohoP . The nitrous acid deamination of n-propylamine under the same conditions yielded an alcohol fraction containing 31% of isopropyl alcohoP. The similarity in the isomer contents of the alcohol portions suggests that common intermediates were involved. The less extensive isomerization of the benzoates may be a reflection of the shorter lifetime of the propyl cations trapped by negatively charged coimter ions compared to those trapped by neutral solvent molecules on the other hand, the role of diazopropane must be determined before definitive conclusions are possible. 

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