Propene molecules

From Fig. 12-6, how many molecules of NO can be oxidized to NO2 by the reaction of one OH free radical with one propene molecule ... 

The newly-formed carhocation either eliminates a proton and forms a dimer or attacks another propene molecule and eliminates a proton, giving the trimer. 

Further protonation of the trimer produces a C9 carhocation which may further react with another propene molecule and eventually produce propylene tetramer. 

Self-Test 3.9B Describe the structure of the propene molecule, CH3—CH=CH2, in terms of hybrid orbitals, bond angles, and a- and -ir-bonds. 

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. 

Co sites in CoZSM-5 and their interaction with propene molecules... 

The present study concerns the interaction of propene molecules with cobalt sites in CoZSM-5. The experiments of CO and NO sorption evidenced that this zeolite contained practically only Co2+ in exchange position and Co3+ in oxide form. Propene is a reactant in several reactions catalyzed by cobalt containing zeolites (like reduction of NO, amonoxidation of propene and others). 

Yet another possibility is illustrated by the propene (or ethylene) dimerization catalyzed by 7r-l,l,3,3-tetraphenylallylnickel bromide (26) activated with ethylaluminum dichloride the isolation of considerable amounts of 1,1,3,3-tetraphenylpropene (27) from the reaction mixture suggests that a hydrogen atom has been transferred from the substrate olefin to the sterically hindered 1,1,3,3-tetraphenylallyl system under formation of 3 [Eq. (7)] (81). The subsequent formation of the HNiY species from 3 can then take place by insertion of a second propene molecule and /3-hydrogen elimination, as discussed above. 

Figure 13. Transition states for propene insertion into the Zr-isobutyl bond of the racemic-dimethylsilyl-bis-l-indenyl zirconocene with a (RJt) coordination of the aromatic ligand. C2 is the overall symmetry of the metallocene, while re and si is the chirality of coordination of the propene molecule in the transition states of parts a and b, respectively.

To start the polymerisation the X atoms in Fig 10.13 are replaced by a growing alkyl chain and a co-ordinating propene molecule. Co-ordination of propene introduces a second chiral element and several diastereomers can be envisaged. The step-by-step regulation of the stereochemistry by the site can be most clearly depicted by drawing the molecule as shown in Figure 10.14, a... 

The hydrogen ion of the acid catalyst is an electrophile and attacks the electron-rich double bond in the propene molecule to form a carbocatlon. 

Taking into account that the main reaction product is formaldehyde and that the propene molecule is double-bonded (just as ethylene), the leaction of oxygen atoms with propene will proceed as follows ... 

The characteristic reaction conditions and the special role of acidic sites in acetone formation accord very well with what is known about the mechanism. The first step in this process is the reversible uptake of a proton by the propene molecule, as evidenced by the D20 experiments carried out with a Sn02—Mo03 catalyst by Buiten [63,64], viz. 

Self-Test 3.9B Describe the structure of the propene molecule,... 

However the propenyl radicals also add to the double bond of other propene molecules. From isobutylene about equal amounts of dimethylhexa-diene and dimethylhexenes are obtained. 

In the propene molecule, four types of nonequivalent hydrogens are designated a through d. 

Prototropic isomerization of the propene molecule in the presence of hydroxide ion has been studied using ab initio and DFT methods in the gas phase and in DMSO solution 152 the mechanism involves formation of an intermediate complex of the allyl anion with a water molecule. 

Semiempirical calculations on the 2+2 photocycloaddition between two propene molecules has suggested that there is a preference for a head-to-tail approach and a concerted pathway [7]. The authors suggest that intermolecular cycloaddition between alkenes with electron withdrawing groups should favor formation of the nms-l,3-disubstituted cyclobutane. 

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