Decomposition of 2-propanol

Although MgO can be considered a basic oxide, the presence of A1 in the mixed oxide may induce some surface acidity. For example, decomposition of 2-propanol over calcined hydrotalcite results in the formation of both propene and propanone which is consistent with the presence of both surface acid and base sites (16). We therefore wanted to test the effect of neutralizing all of the support acidity by... 

Table 14. Photocatalytic decomposition of 2-propanol (reprinted with permission from H. Yoneyama, S. Haga and S. Yamanaka, J. Phys. Chem. 1989, 93, 4833. Copyright 1989 American Chemical Society).

Decomposition of 2-propanol and ethanol Cr-M Both dehydrogenation (minor) and dehydration (major) were observed. 59... 

Cr- FILM from the different cationic forms of this clay [4], These materials exhibited dehydration and dehydrogenation activity in the decomposition of 2-propanol and ethanol. Cr-PILM catalysts activated by HjS/Hj mixture displayed also an interestingly high activity for thiophene hydrodesulfurization (HDS). Now, the Cr-PILM s have been prepared form different clays with the objective to obtain new porous materials with potential catalytic applicability. Their physicochemical properties and the catalytic behaviour for thiophene HDS have been investigated. 

Temperature-Programmed Decomposition of 2-Propanol on the Zinc-Polar, Nonpolar, and Oxygen-Polar Surfaces of Zinc Oxide... 

In view of the interesting results of methanol decomposition, we proceeded to study the decomposition of 2-propanol. It is known that 2-propanol decomposes via two competing pathways. 

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. 

The second difference among the surfaces is the fact that, except H2O, the other three decomposition products, H2, acetone, and propene, were evolved at the same temperature on the two polar surfaces, but H2 was evolved at a lower temperature on the nonpolar surface. It is interesting to compare these results with the observations by Koga et al. who studied the decomposition of 2-propanol at 100 C on ZnO powder (13) They found that if the gas phase 2-propanol was suddenly removed from the gas phase, the evolution of hydrogen continued, but the evolution of acetone stopped. The evolution of acetone resumed after readmission of 2-propanol. This behavior can be explained by the fact that the major exposed face of their ZnO powder sample was the nonpolar plane. It is only on this surface that H2 can be evolved without concurrent evolution of acetone in the absence of gaseous propanol. 

It has been reported that the decomposition of 2-propanol was a structure-insensitive reaction on ZnO (1 ). Our results suggest otherwise. Further work being planned to study steady state reactions on these single crystal surfaces will provide the answer to this discrepancy. 

In conclusion, the chemical properties of ZnO depend on the particular surface plane that is exposed. This surface specificity has now been demonstrated for the decomposition of 2-propanol, methanol, formaldehyde and formic acid, and adsorption and desorption of acetone, propene, water, CO, and CO2. These data have made possible better understanding of the results using ZnO powder. It will be intersting to se<5 how different are the catalytic properties of these surfaces. 

It was the purpose of this work to study the acid/base sites generated upon calcination of layered hydroxides using the decomposition of 2-propanol as a test reaction. Although most of the previously reported catalytic work on this class of materials has involved the Mg-Al hydroxide, other combinations of divalent and trivalent cations are possible and were thus investigated. 

Chen, X Shen, YF Suib. SL O Young. C.I.. Catalytic decomposition of 2-propanol over different metal-cation-doped OMS-2 materials. Journal of Catalysis. 2001 197, 292-302. 

Second, a nano-structured metallic catalyst was also applied to photocatalytic application. Ti(IV)/Ce(III)-MCM-41 was synthesized and used as photocatalysts. Ti(IV)/Ce(III)-MCM-41 are active photocatalysts for the oxidative decomposition of 2-propanol into acetone and CO2 under visible-light irradiation, and a synergy effect of Ti(IV) and Ce(III) has been found [97]. 

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