Isooctene

In other instances, reaction kinetic data provide an insight into the rate-controlling steps but not the reaction mechanism see, for example, Hougen and Watson s analysis of the kinetics of the hydrogenation of mixed isooctenes (16). Analysis of kinetic data can, however, yield a convenient analytical insight into the relative catalyst activities, and the effects of such factors as catalyst age, temperature, and feed-gas impurities on the catalyst. 

Irradiation of butadiene in isooctene solution is reported to yield cyclobutane dimers (8) and (9) in low yield<4) ... 

Numerous examples of applications of nonlinear least squares to kinetic-data analysis have been presented (K7, K8, L3, L4, M7, P2) an exhaustive tabulation of references would, at this point, approach 100 entries. Typical results of a nonlinear estimation and comparison to linear estimates are shown in Table I and discussed in Section III,A,2. Many estimation problems exist, however, as typified in part by Fig. 7. This is the sum-of-squares surface obtained at fixed values of Ks and Ku in the rate equation used for the catalytic hydrogenation of mixed isooctenes (M7)... 

Fig. 7. Contours of sums of squares of residual rates for isooctene hydrogenation, Eq. (46).

As an indication of things to come, a year ago IFF in Paris revealed that it had just launched a commercial process based on ionic liquids that are available for licensing. The Difasol process for dimerizing butenes to isooctenes was developed at Rueil-Malmaison, and pilot-scale trials were carried out at IFP s pilot facilities at the Industrial Research Development Center at Solaize, near Lyon. 

The new Difasol process for manufacturing isooctenes consumes less catalyst. The process dimerizes n-butene in a continuous two-phase operation that uses the industrial Dimersol nickel catalyst dissolved in a chloroaluminate ionic liquid. The n-bu-tenes are introduced continuously into the reactor, and the products are only poorly miscible with ionic liquid, and separate in settler. The process shows 70-80% conversion with 90-95% selectivity (Freemantle, 1998). 

A scheme which was considered by Hougen and Watson (18) and is slightly more complicated is the hydrogenation of isooctene codimer. This illustrates a reaction with a large number of cycles compared with the number of intermediates. 

A supported nickel catalyst was used to study the reaction in which mixed isooctenes, commercially known as codimer, are hydrogenated in the vapor phase to the corresponding isooctanes. Neglecting isomerization, the following steps are assumed to occur ... 

CDTECH/Snamprogetti SpA Isooctene/isooctane Mixed C4 hydrocarbons Isobutylene diemrization to produce isooctene. Additional process can hydrogenate isooctene to produce isooctane 2 1999... 

This is barried out industrially on add catalysts (H2SO4, ion exchange resins) and leads to isooctenes, a mixture of 24-4-trimethyl 1-pentene and 2,2,4-trimetby 12-pentenes. 

The Bayer process operates in the liquid phase at lOO C, in the presence of an ion exchange resin. With a very high conversion ratio (99 per ccntX 75 mole per cent of dimers and 25 per cent of trimers are formed. A 90.000 t/year unit operates on this process in Dormagen [Erdolchemie). The main market for isooctenes is nonyl alcohol, which is used to synthesize plasticizers. 

Olefin Dimerization. Other investigators (Schaad, 1955, Sparks et al., 1939) have reported that the catalytic polymerization of isobutene produced a liquid polymer consisting mainly of isooctenes. Hydrogenation of these isooctenes gave isooctanes consisting of 70 to 90 percent 2,2,4-trimethylpentone the remainder was reported as mainly 2,3,4-trimethyl-pentane. That earlier work used analytical techniques inferior to those now available. Typically, It Is now found that the C0 fraction of Isobutene-isobutane alkylate catalyzed by HF contains about 62.6 percent 2,2,4-trimethylpentane, 13.4 percent 2,3,4-trimethylpentane,... 

Aluminum alkyls are used as Lewis acids and activators for several related transition metal-catalyzed reactions. In the Dimersol process, nickel complexes activated by an aluminum alkyl catalyze alkene dimerization, as in the conversion of butene to isooctene for use in preparing... 

Lewis et al. (74) showed that P/Al catalysts have low activities for hydrocracking of diisopropylbenzene, and the activity of NiMoP/Al catalysts increases as a result of addition of 1-3 wt% phosphorus. On the other hand, Muralidhar et al. (125) reported that isooctene hydrocracking activity of Co—Mo —P/Al catalysts decreases with increasing phosphorus loading. Iwamoto and Grimblot (67) reported that cyclopropane hydrocracking increases with increasing phosphorus content, especially with NiMoP/Al catalysts (Fig. 26). 

Isooctenes (butene dimers) and isoheptenes (propene-butene codimers) are used as feedstocks for oxo synthesis, giving respectively isononanols and isooctanols to produce valuable phthalates. By-product trimers such as isononenes (propene) and isododecenes (butenes) are also hydroformylated to the corresponding alcohols (cf. Section 2.1.1). 

ISOOCTENE (11071-47-9) Forms explosive mixture with air (flash point 23°F/-5°C). May be able to form unstable and explosive peroxides. Incompatible with strong acids, strong oxidizers. Flow or agitation of substance may generate electrostatic charges due to low conductivity ground all equipment containing this material. 

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