Kinetics 1-octene

The unreactivity of cyclohexene (Section II.A) may be explained by the fact that in this case the ring strain of the dimer is much higher than that of the monomer. The observation that cyclohexene can be a reaction product [Eq. (8)] supports the assumption that thermodynamic rather than kinetic limitations prevent cyclohexene from polymerizing. Calderon and Ofstead (24, 100) have observed that bicyc o-[2.2.2]2-octene can be polymerized via ring opening ... 

Structurally, plastomers straddle the property range between elastomers and plastics. Plastomers inherently contain some level of crystallinity due to the predominant monomer in a crystalline sequence within the polymer chains. The most common type of this residual crystallinity is ethylene (for ethylene-predominant plastomers or E-plastomers) or isotactic propylene in meso (or m) sequences (for propylene-predominant plastomers or P-plastomers). Uninterrupted sequences of these monomers crystallize into periodic strucmres, which form crystalline lamellae. Plastomers contain in addition at least one monomer, which interrupts this sequencing of crystalline mers. This may be a monomer too large to fit into the crystal lattice. An example is the incorporation of 1-octene into a polyethylene chain. The residual hexyl side chain provides a site for the dislocation of the periodic structure required for crystals to be formed. Another example would be the incorporation of a stereo error in the insertion of propylene. Thus, a propylene insertion with an r dyad leads similarly to a dislocation in the periodic structure required for the formation of an iPP crystal. In uniformly back-mixed polymerization processes, with a single discrete polymerization catalyst, the incorporation of these intermptions is statistical and controlled by the kinetics of the polymerization process. These statistics are known as reactivity ratios. 

The sterically unencumbered catalyst active site allows the copolymerization of a wide variety of olefins with ethylene. Conventional heterogeneous Ziegler/Natta catalysts as well as most metallocene catalysts are much more reactive to ethylene than higher olefins. With constrained geometry catalysts, a-olefins such as propylene, butene, hexene, and octene are readily incorporated in large amounts. The kinetic reactivity ratio, rl, is approximately... 

It also explains the /Z selectivity of products at low conversions (kinetic ratio. Scheme 19). In the case of propene, a terminal olefin, E 2-butene is usually favoured (E/Z - 2.5 Scheme 19), while Z 3-heptene is transformed into 3-hexene and 4-octene with EjZ ratios of 0.75 and 0.6, respectively, which shows that in this case Z-olefins are favoured (Scheme 20). At full conversion, the thermodynamic equilibriums are reached to give the -olefins as the major isomers in both cases. For terminal olefins, the E olefin is the kinetic product because the favoured pathway involved intermediates in which the [ 1,2]-interactions are minimized, that is when both substituents (methyls) are least interacting. In the metathesis of Z-olefins, the metallacyclobutanes are trisubstituted, and Z-olefins are the kinetic products because they invoke reaction intermediates in which [1,2] and especially [1,3] interactions are minimized. 

A catalyst used for the u-regioselective hydroformylation of internal olefins has to combine a set of properties, which include high olefin isomerization activity, see reaction b in Scheme 1 outlined for 4-octene. Thus the olefin migratory insertion step into the rhodium hydride bond must be highly reversible, a feature which is undesired in the hydroformylation of 1-alkenes. Additionally, p-hydride elimination should be favoured over migratory insertion of carbon monoxide of the secondary alkyl rhodium, otherwise Ao-aldehydes are formed (reactions a, c). Then, the fast regioselective terminal hydroformylation of the 1-olefin present in a low equilibrium concentration only, will lead to enhanced formation of n-aldehyde (reaction d) as result of a dynamic kinetic control. 

A process for the hydroformylation of 1-octene to nonanal was designed for an immobilised homogeneous catalyst. The production capacity was fixed at 100 kton of nonanal. Kinetic data reported for the rhodium catalyst complex of N-(3-trimethoxysilane-n-propyl)-4,5-bis(diphenylphosphino)-phenoxazine immobilised on silica, (2) was used as a starting point. Other process specifications are given in Table 3.8. 

Quite new ideas for the reactor design of aqueous multiphase fluid/fluid reactions have been reported by researchers from Oxeno. In packed tubular reactors and under unconventional reaction conditions they observed very high space-time yields which increased the rate compared with conventional operation by a factor of 10 due to a combination of mass transfer area and kinetics [29]. Thus the old question of aqueous-biphase hydroformylation "Where does the reaction takes place " - i.e., at the interphase or the bulk of the liquid phase [23,56h] - is again questionable, at least under the conditions (packed tubular reactors, other hydrodynamic conditions, in mini plants, and in the unusual,and costly presence of ethylene glycol) and not in harsh industrial operation. The considerable reduction of the laminar boundary layer in highly loaded packed tubular reactors increases the mass transfer coefficients, thus Oxeno claim the successful hydroformylation of 1-octene [25a,26,29c,49a,49e,58d,58f], The search for a new reactor design may also include operation in microreactors [59]. 

The detailed kinetic study of octene-1 epoxidation by. veodecylsulfonic peracid was performed [25,42]. The 1,2-octanediol monodecylsulfonate was identified as the main product of the reaction. The kinetic dependence of the reaction rate (v) on the reactants concentration obeys the equation... 

The observed order in propene concentration is less than one, which might point to saturation kinetics. Indeed, high concentrations were used, but perhaps the non-ideal behaviour of propene (critical temperature 94 °C) plays a role in this. Under similar conditions for 1-hexene and 1-octene a neat first order behaviour in alkene has been observed using Rh-PPh3 catalysts [36,42],... 

As mentioned earlier, in the Ruhrchemie-Rhone Poulenc process for propene hydroformylation the pH of the aqueous phase is kept between 5 and 6. This seems to be an optimum in order to avoid acid- and base-catalyzed side reactions of aldehydes and degradation of TPPTS. Nevertheless, it has been observed in this [93] and in many other cases [38,94-96,104,128,131] that the [RhH(CO)(P)3] (P = water-soluble phosphine) catalysts work more actively at higher pH. This is unusual for a reaction in which (seemingly) no charged species are involved. For example, in 1-octene hydroformylation with [ RhCl(COD) 2] + TPPTS catalyst in a biphasic medium the rates increased by two- to five-fold when the pH was changed from 7 to 10 [93,96]. In the same detailed kinetic studies [93,96] it was also established that the rate of 1-octene hydroformylation was a significantly different function of reaction parameters such as catalyst concentration, CO and hydrogen pressure at pH 7 than at pH 10. 

The presence of 4e as the predominant species during the catalysis is also in accord with the observed kinetic behavior of this catalyst with 1-octene and styrene as the substrates. The observation of this saturated acyl rhodium complex is in line with the positive dependence of the reaction rate on the hydrogen concentration and the zero order in alkene concentration. It was concluded previously that this saturated acyl complex is an unreactive resting state [18]. Before the final hydro-genolysis reaction step can occur, a CO molecule has to dissociate in order to form... 

RuCl2(H20) ]+ This species was made from RUCI3 in HCl from pH 0.4-2.0. Kinetic studies suggest that in the epoxidation by [Ru(7l2(H20)4]X02/water-dioxane of cyclo-octene and -hexene homolytic cleavage of the 0-0 bond plays an essential part [771, 772], and that this is so for similar oxidation of alkanes (e.g. of cyclohexane to cyclohexanol) [771],... 

Kinetic Method. 1-Octene (73.6 grams), 0.01 gram of Mo(CO)e, and 200 ml. of benzene were placed in a 500-ml. three-necked flask equipped with a septum, thermometer, condenser, magnetic stirrer, and addition funnel wrapped with a heating tape. The solution was brought... 

Olefin polymerization using heterogeneous catalysts is a very important reaction and stereochemical aspects have been studied extensively. For a review on this topic see Pino et al. [9], Briefly, the origin of stereoregularity in polyolefins (47) is explained by the chiral nature of the acdve site during polymerization. If the absolute configuration of the first intermediate can be controlled by chiral premodification then we should obtain a non-racemic mixture of R - and "S"-chains. This has indeed been observed e.g. with catalyst M4 for the polymerization (partial kinetic resolution) of racemic 3,7-dimethyl-l-octene (ee 37%) and also for the racemic monomer 46 using Cd-tartate M5. 

Fe111 and Co111 corroles catalyze the reaction between alkene and hydroxide. The product is either an alcohol or a ketone depending on the substrate.241 The kinetics are first order in both alkene and hydroxide ion, and the rate increases in the order ethoxyethylene > styrene > 1-octene. No intermediates such as alkylmetal complexes have been detected spectroscopically. These observations suggest a mechanism involving an initial metal-alkene n complexation followed by rate-determining hydroxylation (Scheme 80). 

Retro-cycloaddition extrusion of the metaphosphate moiety from 2,3-oxa-phosphabicyclo[2.2.2]octene derivatives (79), in 1,2-dichloroethane at 100 °C in the presence of PrOH, has been shown to proceed via an unsymmetrical transition state in which C—P bond breakage and P=0 bond formation are more advanced than C—O breakage.39 The secondary deuterium isotope effect on H adjacent to the P—C bond is 1.060 0.008 for (79a) and 1.081 0.009 for (79b) and the oxygen kinetic isotope effect on the P—O—C bridge is 0.9901 0.0016 for (79a). 

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