2-propanol, decomposition

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... 

The decomposition of 2-propanol showed both similarities and differences among the surfaces. The most notable similarity is the fact that propene and acetone were produced at about the same ratio on all surfaces. Dehydrogenation to form acetone was the dominant reaction, as has been observed on ZnO powders ( ). The desorption temperatures of the reaction products, acetone, propene, and hydrogen were always higher than the temperature of desorption of the adsorbed acetone, propene, and hydrogen (hydrogen does not adsorb on ZnO under our conditions). Thus the evolution of acetone and propene are reaction limited in 2-propanol decomposition. 

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. 

From the temperature at which the decomposition products evolved, it would seem that the 0-polar surface should be the most active in 2-propanol decomposition. However, a close examination of the temperatures in Table I shows that on the 0-polar surface, the desorption temperature of the minor product water was actually rather high - higher than any of the products from the nonpolar surface. Thus in a steady state reaction at temperatures below about 100 C, the 0-polar surface could be easily poisoned by adsorbed water, leaving only the nonpolar surface active. 

The reaction order for 2-propanol decomposition was estimated by varying the residence times and was found to be approximately zero order at low conversions. Reaction rates were estimated based on this reaction order. The derived activation energies are approximate due to lack of precise knowledge of the particle size in the catalyst bed. 

Table III lists the physical and XRD characteristics of the samples after calcination at 450°C. During 2-propanol decomposition at low conversions (<5%) the only products detected were acetone and propylene. At higher conversions secondary...

Table IV. Apparent Activation Energies for 2-Propanol Decomposition over Calcined Double Hydroxides...

The effect of the ratio of divalent to trivalent cation on 2-propanol decomposition was investigated for the Mg-Al system. As Figure 4 shows the Mg-Al hydroxide with the highest Al/Mg ratio displayed poorest activity but the highest selectivity towards ketone formation. 

Figure 3. Product distribution for 2-Propanol decomposition over samples G through I.

The combination of spectral techniques and reaction results revealed contrasting features for the Ni-Al and Mg-Al hydroxide systems as they undergo calcination. The Ni-Al hydroxide after calcination showed the distinct presence of NiO and tetrahedrally coordinated Al, and a lack of octahedrally coordinated Al. 2-Propanol decomposition studies showed that Ni-Al and NI systems display similar selectivity. This suggests that during... 

Activity and selectivity of nanosized nickel ferrites have been studied for hydrogen and syngas prodnction via the CO2 reforming of methane (DRM). The catalysts were prepared by two different methods (i) co-precipitation (CP) route using nitrates salts as precursors and (ii) hydrothermal (HT) method using chlorides as starting salts. The materials were characterized by several techniques HT-XRD, TGA-DTA, XRD, BET, LRS, TPR, SEM. Surface acid-base measurements were performed by 2-propanol decomposition (IPA) and catalysts were tested in DRM reaction. A relationship is established between the method of preparation, the solid structure, the surface acid-base properties and the catalytic activity of iron-nickel solids in DRM reaction. The surface acid-base properties seem to play an important role in DRM reaction. 

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