Dehydration of propanol

The water-insoluble salts such as Cs2,5Ho., iPWi204o efficiently catalyse dehydration of 2-propanol in the gas phase and alkylation of m-xylene and trimethyl benzene with cyclohexene this catalyst is much more active than Nafion-H, HY-zeolite, H-ZSM-5, and sulphated zirconia (Okuhara et al., 1992). 

Izumi and Urabe [105] found first that POM compounds could be entrapped strongly on active carbons. The supported POMs catalyzed etherization of ferf-butanol and n-butanol, esterification of acetic acid with ethanol, alkylation of benzene, and dehydration of 2-propanol [105], In 1991, Neumann and Levin [108] reported the oxidation of benzylic alcohols and amines catalyzed by the neutral salt of Na5[PV2Mo10O40] impregnated on active carbon. Benzyl alcohols were oxidized efficiently to the corresponding benzaldehydes without overoxidation ... 

Figure 4.15 Light-off curve for the dehydration of 2-propanol by a Si8O20-building block catalyst initially containing 3-connected, atomically dispersed aluminium atoms. Conditions 55 mg catalyst, 95ccmin total flow across catalyst, WHSV 0.4 h. ...

Kinetic isotope effects of deuterium ( h/ d) n the dehydration of 2-propanol on various catalysts at 300°C [123]... 

Fig. 31. Catalytic activities of acidic Na or Cs salts of HjPW 204o as a function of Na or Cs content, (a) M = Na (O) dehydration of 2-propanol, (A) decomposition of formic acid, ( ) conversion of methanol, ( ) conversion of dimethyl ether, (b) M = Cs (O) dehydration of 2-propanol, ( ) conversion of dimethyl ether, (A) alkylation of 1,3,5-trimethylbenzene with cyclohexene. (From Refs. 46 and 128.)...

There is evidence that at least two different pseudoliquid phases may be present, even during catalytic reactions, and these may change reversibly with changes in the reactant partial pressures, as shown for dehydration of 2-propanol in Fig. 39 (242). A small change in reactant partial pressure led to an abrupt... 

Fic. 39. Pressure dependence of the catalytic reaction rate and the amount of absorbed propanol in the dehydration of 2-propanol catalyzed by H3PW12O40 at 353 K. (From Ref. 242.)... 

As shown in Fig. 44a, the catalytic activity of NaxH3- PW,2O40 for dehydration of 2-propanol, conversion of methanol, and decomposition of formic acid decreased monotonically with the Na content in the salts. The activities for these... 

Only linear butenes are present in the reaction products, whereas isobutylene and other products would be expected for strongly acidic catalysts. Furthermore, the activity for the dehydration of 2-propanol is low in the Si02-rich region and greater in the Ti02-rich region. 

Tanabe el al. studied in detail the catalytic action and properties of metal sulfates most of the sulfates showed the maximum acidity and activity by calcination at temperatures below 500°C, with respect to the surface acidity and the acid-catalyzed reaction (118, 119). Other acid-catalyzed reactions were studied with the FeS04 catalyst together with measurement of the surface acidity of the catalyst the substance calcined at 700°C showed the maximum acidity at Ho s 1.5 and proved to be the most active for the polymerization of isobutyl vinyl ether, the isomerization of d-limonene oxide, and the dehydration of 2-propanol (120-122). It is of interest that the catalyst calcined at a slightly higher temperature, 750°C, was completely inactive and zero in acidity in spite of the remarkable activity and acidity when heat treated at 700°C. 

Sommer S and Melin T. Design and optimization of hybrid separation processes for the dehydration of 2-propanol and other orgnanics. Ind. Eng. Chem. Res. 2004 43(17) 5248-5259. 

As catalytic tests four reactions, isomerization of 1-butene and methyloxirane, dehydration of 2-propanol and the pinacol rearrangement of 2,3-dimethyl-2,3-butanediol were used. 

Dehydration of 2-propanol (pulse technique, 473 K, average of five 1-pl pulses) activity 0 0.42 2.45 2.59... 

S. Sommer, T. Melin, 2004, Design and Optimization of Hybrid Separation Proeesses for the Dehydration of 2-Propanol and Other Organics, Ind. Eng. Chem., vol. 43, 5248-5259. 

Figure 5. Rate of dehydration of 2-propanol versus strong acidity for chlorided y-alumina catalysts...

When metals are incorporated on chlorided AI2O3-G catalyst both acid and metal sites are available for the reaction. Thus, in addition to dehydration, dehydrogenation product acetone was also formed with Pt/A Os-H catalyst. Sn/AbOa-I has also been found active for dehydration of 2-propanol to propylene which could be due to the presence of Sn cations acting as Lewis acid sites as tin is practically unreduced when added to alumina in... 

The chlorided aluminas have demonstrated a linear correlation between the dehydration of 2-propanol to propylene and strong acidity. Pt/Al203 and Pt-Sn/Al203 are catalytically active for both dehydration and dehydrogenation reactions. 

The catalytic properties of metal-zirconium phosphate solid has also been investigated (21, 349). The catalysts were prepared by the ion exchange of zirconium phosphate with copper, nickel, and chromium ions. Cataljdic dehydration of 2-propanol was studied at 160°-350°C, with zirconium phosphate itself giving the highest activity, yielding 97% propylene at 230°-240°C. Introduction of Cu +, Ni +, and Cr " decreased the dehydrating properties, and also decreased the catalytic isomerizing properties when tested with the cyclohexane-methylcyclopentane isomerization. The introduction of copper and nickel improved the dehydration properties of zirconium phosphate when tested on ethylbenzene. 

Aramendia. MA Borau. V Jimenez, C Marinas. JM Porras. A Urbano, FJ. Magnesium oxides as ba.sic catalysts for organic processes. Study of the dehydrogenation-dehydration of 2-propanol. Journal of Catalysis. 1996 I6I. 829-838. 

The selectivities of rare earth oxide catalysts for dehydration of 2-propanol and butanols have been examined recently by Bernal and Trillo (1980) as a function of reaction temperature. No definite variations of selectivity have been observed along the lanthanide series, but the highest percentage of 1-butene was found on H02O3 and LU2O3 and the lowest on La20j. This is opposite to what was expected on the basis of the respective basicities of these oxides. Bernal and Trillo (1980) have noted that the reaction temperature influences product distributions, and that care has to be exerted in establishing trends of a series of related catalysts because of these temperature effects. 

A thin, high flux, and highly selective cross-linked PVA water-selective layer on top of hf ceramic supports was prepared by Peters et al. (2006). The support was an a-AljOj hf substrate and an intermediate Y-AI2O3 layer, which provided a sufficiently smooth surface for the deposition of ultrathin PVA layer. The thickness of the PVA layer formed on top of the y-Al203 intermediate layer was on the order of 0.3-0.8 pm. In the dehydration of 1-butanol (80°C, 5 wt% water), the membrane exhibited a high water flux (0.8-2.6 kg/m h), combined with a high separation factor (500-10,000). The values for the flux and separation factor exceeded typical values obtained for cross-linked PVA membranes on polymeric supports. In the dehydration of 2-propanol and 1-butanol, a simultaneous increase in both the water flux and the separation factor was observed with increasing temperature or water concentration. 

PRACTICE PROBLEM 7.12 Dehydration of 2-propanol occurs in 14 M H2SO4 at 100°C. (a) Using curved arrows,... 

A microchannel reactor designed for periodic operation and a process to deposit alumina as a catalyst inside the reactor channels can also be used for the dehydration of 2-propanol to propene [23]. 

The gas-phase microreactor can be used on the laboratory scale under maximum conditions of 3 bar and 500 °C. It is made up of a stack of stainless-steel micro-structured plates that are arranged for counter-flow or co-current flow practice. Already tested applications of this reactor include the dehydration of 2-propanol [109]. 

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