Hydrogenation of propylene

Physical Methods that have been Used to Monitor Reaction Kinetics. In this section some physical property measurements of general utility are discussed. One of the oldest and most useful techniques used in kinetics studies involves the measurement of the total pressure in an isothermal constant volume reactor. This technique is primarily used to follow the course of homogeneous gas phase reactions that involve a change in the total number of gaseous molecules present in the reaction vessel (e.g., the hydrogenation of propylene). 

Shabaker (SI), for the hydrogenation of propylene over a platinum alumina catalyst, selected a Hougen-Watson model of the form... 

As an illustration, consider the hydrogenation of propylene over a platinum alumina catalyst discussed in Section II. These date were taken from 0 to 35°C, 1 to 4 atm total pressure, and 0 to 45 % propylene. Equations (7) and (8) were obtained after considerable sifting and winnowing of rate equations. Both fit the observed data reasonably well. 

Supported metal catalysts with molecular sieving properties75,76 are able to differentiate between alkenes with structures of differing steric demands in competitive hydrogenation. After an early report on the selective hydrogenation of propylene in the presence of isobutylene over a Pt-zeolite A catalyst77 new examples have recently been published78-84. 

Hydrogenation of propylene to propane (T=1000C) Pd Pd (foil) Reaction rate is only slightly enhanced by Pd membrane Nagamotoand Inoue, 1985... 

Chemical and physical evidence indicate the follow ing species to be present in the hydrogenation of propylene (CaHe) on supported platinum (Pt) ... 

Rogers, G. B., Kinetics of the catalytic hydrogenation of propylene, PhD thesis. University of Wisconsin-Madison (1961). 

Shabaker, R. H., Kinetics and effectiveness factors for the hydrogenation of propylene on a platinum-alumina catalyst, Ph. D. thesis. University of Wisconsin-Madison (1965). 

Investigation 9 dealt with reaction rate models for the catalytic hydrogenation of propylene over Pt-alumina. Computations via Eq. (7.1-15) were given for 15 reaction models, the best of which were constructed from evidence on multiple surface species along with the reactor data. 

Thus the alloy 74.9% Co -(-21.7% Fewith the latticeAl is still active, and the alloys 50% Co + 50% Fe and 24.2% Co + 75.8% Fe with a lattice A2 are not. Copper seems to be an exception (see above). Rie-niicker and Unger (207) carried out a similar very accurate study applying X-ray analysis and adsorption measurements of the surfaee the results supported the requirements of the multiplet theory. Recently, Rieniicker (208) found that for the hydrogenation of propylene (which proceeds according to the model of Fig. 6) binary alloys of Ni and Fe of diffei ent composition are also active only until they have a nickel structure, i.e., Al, which is in conformity with the multiplet theory. 

Table II. Hydrogenation of Propylene at 44 C and 500 psi of Hydrogen in Chloroform with [PtCl2L2] - - SnCL 2H2O...

The rate of hydrogenation of propylene on a test catalyst has been measured as 0.2mol/cm cat.-h in an experiment conducted in a fixed bed at a particle Reynolds number of 1000 and an isothermal fluid temperature of... 

In a similar study of the hydrogenation of allene in the presence of [14-C]-propylene, over supported Rh and Pd, the amount of propane produced from the further hydrogenation of propylene was found to be very small compared with the total propane yield. By analogy with the acetylene system, it was proposed that the formation of propane occurs by a route not involving the formation of propylene as a gas phase intermediate. 

The hydrogenation of propylene was earned out in a semibatch reeireulation reaetor with a Pt/Si02 catalyst (Vorhis, F.H., M.S. thesis, Cornell University, 1968). The reaction was first order to hydrogen and showed a complex dependence on propylene pressure. Data for a typical run are given in Table 2.2. 

The hydrogenation of propylene by platinum [28] and rhodium [29] fixed on inorganic (AI2O3, MgO) and polymeric (nylon-66, nylon-610) supports, was conducted in flow and cyclic reactors. The reaction rate depended on the type of support used and was highest for platinum/nylon samples. Treatment of the catalyst at 130-140 C led to a full loss of the metal catalytic activity as a result of the destruction of the polymeric support. Similar results were also shown for tin. Apparently [29] the incorporation of tin caused formation of bimetallic clusters and influenced the electronic state of platinum. 

Starodubtseva, E.V. (1990) Sorption and catalytic properties of intermetallic compounds in reaction hydrogenation of propylene and enantioselective hydrogenation of ethyl acetoacetate, Cand. Diss. Thesis, N.D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of ihe USSR, Moscow (supervisors Klabimovskii, E.l. and Konenko, I.R.). 

In the latter reaction, metallic nickel may catalyze hydrogenation of propylene to propane. Traces of ethane and butane found as by-products probably arise from methyl free radical reactions. 

Vaska s complex, [Ir(CO)(PPh3)2Cl] immobilized onto phosphine-modified silica showed very low activity in Uquid-phase hydrogenations. In gas-phase hydrogenations of propylene at about 70 °C, significant product yield and some weak PHIP effects were observed. In contrast, gas-phase propyne hydrogenation at about 110 C provided very little product but the signal enhancement for... 

Figure 7.7 H NMR spectra detected during the hydrogenation of propylene using the IRMOF-3-SI-Au catalyst and (a) normal Hj or (b) pHj. The enhanced antiphase signals...

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