Isomerization n-octene mixtures

Kuus, M. Toome, M. Kudryavtseva, L. Eizen, O. The thermodynamic properties of n-octane - isomeric n-octene mixtures [Russ]. Eesti NSV Tead. Akad. Toim., Keem. 1980, 29, 32-37. 

Maximum yield of epoxides can be expected with molecules, first 1,1-dimethy-lalkenes, which prefer addition to abstraction (allyl hydrogen removal).11,259,260 These oxidations are not steroselective mixtures of the isomeric oxiranes are formed in the reaction of isomeric n-octenes.261 This was interpreted as additional evidence of the formation of radical intermediate 28 allowing the rotation about the carbon—carbon bond. 

Kuus, M. Kudryavtseva, L. Kirss, H. ESsen, O. Vapor-liquid equilibrium for binary mixtures of isomerical n-octenes with some solvents Monatsh. Chem. 1981,112,415-420... 

It is generally accepted that the Pt/ZrCyS04 have both a metal and an acid function. The feedstock was switched from n-hexadecane to a 10 wt.% 1-octene/n-C16 mixture in the runs described above in order to determine if the metal function was deactivated. As can be seen in Figure 1, all of the 1-octane was converted using both the 0.6 and 5.0 wt.% Pi catalysts. The major product of the 1-octene conversion was n-octane. Little of the 1-octene was isomerized (0.50 wt.%) to methylheptanes. The fact that n-octane was the major product indicates that the metal function was not deactivated with respect to the function responsible for isomerization and was therefore not responsible for the low conversions of n-hexadecane. This fact plus the low yield of isomerization products (methylheptanes) from n-octene suggest that the acid sites have been deactivated in both catalysts. 

In 1945, Campbell and McDermott [32] found that the reduction of diaUcylacety-lenes by calcium hexamine [CafNI-Isle] in diethyl ether yielded the corresponding trans alkenes. In 1984, Benkeser and Belmonte [33] reported results from detailed studies of the reduction of internal and terminal alkynes by calcium in a mixture of methylamine and ethylenediamine (1 1 v/v). For example, reduction of 4-oc-tyne gives a mixture of isomeric trans octenes in 75% overall yield it includes trans-2-, 3-, and 4-octenes in the ratio 1 9 88. Treatment of 1-heptyne, a terminal alkyne, with a fivefold excess of calcium produces 70% of a mixture containing 87% n-heptane, 7% tra s-2-heptene, and 3% 1-heptene. 

Using mild reaction conditions (10 bar, 125 °C), a high conversion of trans-4-octene and a high selectivity to n-nonanal can be obtained with toluene as the solvent. Cyclic carbonates like propylene carbonate (PC) are also suitable solvents for the isomerizing hydroformylation of trans-4-octene. Furthermore, the selectivity to -nonanal is increased up to 95% when PC is used in a single phase. The product n-nonanal can be extracted with n-dodecane or with a mixture of dodecane isomers. 

TMS systems, which were used in the isomerizing hydroformylation of frans-4-octene, should be apphcable to hydroaminomethylation as well because the hydroformylation is the first step of the reaction. For this reason similar TMS systems were apphed in a first series of investigations [40]. Propylene carbonate (PC) was chosen as the polar solvent si for the catalyst and alkanes (an isomeric mixture of dodecane or n-hexane) were used as non-polar component s2. 1.4-Dioxane, different pyrrohdones [N-methylpyr-rolidone (NMP), JV-ethylpyrrohdone (NEP), M-cyclohexylpyrrolidone (NCP) AT-benzylpyrrolidone (NBP) and N-octylpyrrohdone (NOP)] or esters of lactic acid (ethyllactate and butyllactate) served as mediator s3. As a test reaction the hydroaminomethylation of 1-octene with morphohne was investigated (Scheme 7). 

Fig. 1 shows 1-octene conversion versus time for the homogeneous and heterogenized complex on supports ROX-0.8 and ROX-N for the last case, results in three consecutive reaction runs are included. Products are a mixture of linear (L) and branched (B) isomers of aldehydes. Selectivity at 2 and 7 h (expresed as L/B) is also included in the figure. In general, the curves present a shape with two steps with different rates. These data show that i) in the first step (faster), the linear aldehyde is mainly obtained. Increase of the branched product is related to the easy isomerization of 1-octene to 2-octene in these kinds of complexes mainly when the diene ligands are replaced by CO ii) the selectivity of these... 

Highly active unmodified rhodium catalysts for the hydroformylation of various olefins in SCCO2 are formed under mild conditions from [(cod)Rh(hfa-cac)] (8 cod = cis,cis-l,5-cyclooctadiene) and a number of other simple rhodium precursors [24]. Especially for internal olefins, the rate of hydroformylation is considerably higher than using the same catalysts in conventional liquid solvents under otherwise identical conditions. A detailed study of the hydroformylation of 1-octene (Scheme 6) using the online GC setup shown in Fig. 3 revealed a network of competing isomerization and hydroformylation when 8 was used without additional modifiers. As a result, the regioselectivity for the desired linear n-aldehyde varied considerably with conversion. At 60% conversion, the product aldehydes contained almost 80% of nonanal, whereas only 58 % linear aldehyde were present in the final product mixture. 

Hydroesterification with Co catalysts most commonly utilize pyridine or alkyl pyr-idines such as -y-picoline as cocatalysts. In a massive screening study, Co with pyridine promotors, unsubstituted in the ortho positions, gave the highest proportion of linear esters with either 1-octene oi a mixture of isomeric internal n-dodecenes. The promoter comparison was conducted at 160 C and 16.0 MPa for octene and 170°C and 18.0 MPa for the internal dodecenes, in both cases in an excess of CH3OH. The maximum rate for... 

The hydroformylation of mixtures of Cg-olefins is a process with huge economic importance. A typical example is di-n-butene, consisting of isomeric -octenes, methylheptenes, and dimethylhexenes. The mixture is produced from Raffinate II, in which isomeric butenes are dimerized (e.g., by IFP Dimersol [47] or Octol process [48]). Hydroformylation of di- -butene produces linear and alkyl-branched Cg-aldehydes, which are converted to diisononyl phthalate (DINP), another additive for flexible PVC with immense industrial relevance. For this application, the use of terminal aldehydes is preferred. 

The transfer dehydrogenation of w-octane was tested 2 years later including complexes bearing N-tert-hutyl (47e) and Af-adamantyl (47f) substituents. However, only complexes 47a and 47d showed catalytic activity in this reaction with small TONs of 12 and 10 under the same conditions used for the transfer dehydrogenation of cyclooctane [16b]. As already known from the reactivity of PCP Ir pin-cer complexes [43], Chianese observed only internal isomers of octene and therefore investigated the activity of complex 47a in the isomerization of 1-hexene. Already after 15 min at 150 "C, 1-hexene was isomerized with a TON of 420 to a mixture of tr ws-2-hexene, cis-2-hexene, and 3-hexenes in a 67 29 4 ratio and after 60 min (TON 730) in a 65 26 8 ratio. Therefore the isomerization of terminal olefins is much faster than the transfer dehydrogenation. It was also concluded that the isomerization of terminal olefins is much faster than that of 2-hexenes to 3-hexenes. The isomerization of 1-octene was shown to proceed already at 100 °C with identical TON of almost 500 and nearly complete consumption of 1-octene after 24 h for 47a, 47e, and 47f. In this case, the addition of NaO Bu is required (Figure 9.14). 

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