Propene reactions

The important hydrocarbon classes are alkanes, alkenes, aromatics, and oxygenates. The first three classes are generally released to the atmosphere, whereas the fourth class, the oxygenates, is generally formed in the atmosphere. Propene will be used to illustrate the types of reactions that take place with alkenes. Propene reactions are initiated by a chemical reaction of OH or O3 with the carbon-carbon double bond. The chemical steps that follow result in the formation of free radicals of several different types which can undergo reaction with O2, NO, SO2, and NO2 to promote the formation of photochemical smog products. 

Fig. 12-5. Ozone-propene reaction pathways showing oxidation products.

For the NO+propene reaction the values were obtained directly from experiment by gas chromatographic measurement of the N2 production. 

YCH2 + C2H4 Formation from the Propene Reaction 253... 

In the propene reaction, both YCH2 and YC3H4 were again observed. The YC3H4 data at EC(J = 25.2 kcal/mol were similar to those observed for the cyclopropane reaction at 18.5 kcal/mol. From the difference in enthalpies... 

In an effort to further support the proposed mechanisms for the Y+propene reaction, we have examined the reactions of Y with four isomeric butenes, which are essentially propene molecules with one additional methyl group (Fig. 31). Based on estimated potential energy barrier heights22 and thermodynamics (Fig. 32))22-31-34,i56,i57 q js eXpected that analogous product channels to those observed for propene should be seen for the butenes. Therefore, a comparison of reactions of butene isomers to reactions with propene should allow us to further test the validity of the proposed mechanisms. Here we briefly summarize our most notable conclusions from this work. 

Fig. 40. Lab angular distributions for YC3H4 (open circles), YH2 (open triangles), and YCH2 (open squares) products from the Y +propene reaction at con = 28.8 kcal/mol. Corresponding product yields are given in the upper right corner of each graph. Note that each distribution is scaled to the same number of scans (2).

Fig. 3 Long-term stability of Rh-3-SILP catalyst in continuous gas-phase hydroformyla-tion of propene. (Reaction conditions T = 100 °C, ptotai = 10 bar with pH2 = Pco =4.1 bar andppropene = 1.8 bar, M hodium = 3-53 X 10 mol, r = 0.38 s) [31]...

In the case of unsymmetrical alkenes, the OH radical can add to either end of the double bond. There is evidence that, as expected, it preferentially adds to form the secondary radical. For example, for the propene reaction (Cvetanovic, 1976), 65% of the adducts formed correspond to (34a) and 35% to (34b) ... 

Described in this paper is a model system - one in which well-characterized lanthanide complexes exhibit high catalyst activities for ethylene polymerization but where the corresponding oligomerization of propene is sufficiently slowed so that stepwise insertion of the olefin can be studied quantitatively and all important intermediates observed or isolated. Emphasized in this paper is the effect of added Lewis acids and bases on the rate of olefin insertions, and comparison between ethylene and propene reactions. The catalysts, of general structure M(ri -Cp )2CH3 L (M = Yb, Lu ... 

The authors have tried the method to apply photoreaction of metal carbonyl on solid surface for preparation of catalysts, and have found that metal carbonyls, M(CO)g(M=Mo, W), adsorbed on porous Vycor glass are activated as catalysts by their irradiation with UV light in the presence of reactants (20). Fig.6 shows a time course of the propene reaction carried out on the Mo(CO)g-, W(CO)g- or Cr(CO)g-adsorbed porous Vycor glass(denoted by Mo(CO)g/PVG, etc., hereafter). No reaction occurs under darlc. Propene is converted to equal molar amounts of ethene and butene under the irradiation of Mo(CO)g/PVG and W(CO)g/PVG, but no activation of Cr(CO)g/PVG has been observed. This result indicates the photoinduction of the catalytic activity of Mo(CO)g/PVG and W(CO)g/PVG for the metathesis of propene. The reaction continues for about 30 min even after the stop of the... 

One of the important catalytic processes based on shape selectivity is the alkylation of biphenyl with propene (Reaction 4). Pinnavaia et al. have shown that mesoporous clays such as K10 and alumina-pillared montmorillonite are more selective than homogeneous acid catalysts, although not as... 

The extent of reversibility for the H atom—propene reaction is unknown. The greater stabilization possibilities in the isopropyl radical as compared with the ethyl radical will make reversibility less important. 

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