Dodecenes, branched

Propjiene (qv) [115-07-1] is the predominant 0x0 process olefin feedstock. Ethylene (qv) [74-85-1J, as well as a wide variety of terminal, internal, and mixed olefin streams, are also hydroformylated commercially. Branched-chain olefins include octenes, nonenes, and dodecenes from fractionation of oligomers of C —C olefins as well as octenes from dimerization and codimerization of isobutylene and 1- and 2-butenes (see Butylenes). 

An olefin may be hydroformvlated to a mixture of aldehydes. The aldehydes are readily converted to alcohols by hydrogenation. Many olefins from ethylene to dodecenes are used in the 0X0 reaction, 0X0 alcohols are typically a mixture of linear and methyl branched primary alcohols. See also Oxo Process. 

Polymers. The manufacture of alcohols fiom higher olefins via the oxo process for use m plasticizers is a significant outlet for both linear a-olefins and branched olefins such as heptenes, nonenes, and dodecenes. These olefins are converted into alcohols containing one more carbon number than the original olefin. The alcohols then react with dibasic anhydrides or adds to form PVC plasticizers. The plasticizers produced from the linear olefins have superior volatility and cold-weallier flexibility characteristics, making them an ideal product to use in flexible PVC for automobile interiors. 

Copolymerizations of BD with 1-alkenes such as 1-octene and 1-dodecene aim at short chain branching of BR. Kaulbach et al. used the ternary catalyst system NdO/TIBA/EASC (htiba/ Nd = 25, nci/nNd = 3) for the respective copolymerizations of BD/l-octene and BD/l-dodecene [508]. These authors showed that only small amounts of 1-alkenes are incorporated and that no neighboring 1-alkene moieties are present in the copolymer. The copolymerization parameters have been determined by the method of Kelen-Tiidos rBD = 25 and ri-octene 0 rBD = 18 and r dodecene = 0.1. With increasing amounts of 1-alkene in the monomer feed catalyst activity decreases drastically. The cis- 1,4-contents of the BD units in the copolymer were around 90% and were barely affected by increases of the 1-alkene content in the monomer feed. 

In the production of linear alkylbenzenes zeolites with ten membered rings yield the desired product, the 2-phenyl isomer, vriiich is the smallest of the isomers, more selectively, but the activity of these zeoUtes is low [98], In a conparative study of several wide pore zeolites it was observed that the selective towards 2-phenyl dodecane in the reaction of dodecene with benzene at 498 K, 0.6 MPa and alkene to benzene ratio of 0.1 decreased in the order H-Mordenite > H-Beta > HY> amorphous silica-ahunina >RE-YwHF. Ahhou the production of the 2-phenyl isomer is desirable in the production of LAB, it is much more inportant to avoid the formation of diphenyl-isomers and branched phenyl isomers. The production of these conpounds can be suppressed by using HY as a catalyst [98,60],... 

Derivation Benzene is alkylated with dodecene, to which it attaches itself in any secondary position the resulting dodecylbenzene is sulfonated with sulfuric acid and neutralized with caustic soda. For ABS (branched-chain alkyl) the dodecene is usually a propylene tetramer, made by catalytic polymerization of propylene. For LAS (straight-chain alkyl), the dodecene may be removed from kerosene or crudes by molecular sieve, may be formed by Ziegler polymerization of ethylene, or by cracking wax paraffins to a-olefins. 

When 1-dodecene was passed over the catalyst at 300°C the product distribution shown in Fig. 5 was obtained. Within any one carbon number the ratio of branched chain/straight chain molecules was very high, being about 4 1 for C s and 3 1 for Cg s. The lifetime of catalysts was substantially reduced by cracking but as the cracking activity decreased the ability of the catalyst to skeletally isomerize without cracking became apparent. Thus, after 21 hours cracking of 1-dodecene at 300°C the products from the catalyst consisted almost entirely of branched (but unidentified) dodecenes. 

In order to eliminate the possibility for in situ carbene formation Raubenheimer et al. synthesized l-alkyl-2,3-dimethylimidazolium triflate ionic liquids and applied these as solvents in the rhodium catalyzed hydroformylation of l-hejEne and 1-dodecene [178]. Both, the classical Wilkinson type complex [RhCl(TPP)3] and the chiral, stereochemically pure complex (—)-(j7 -cycloocta-l,5-diene)-(2-menthyl-4,7-dimethylindenyl)rhodium(i) were applied. The Wilkinson catalyst showed low selectivity towards n-aldehydes whereas the chiral catalyst formed branched aldehydes predominantly. Hydrogenation was significant with up to 44% alkanes being formed and also a significant activity for olefin isomerization was observed. Additionally, hydroformylation was found to be slower in the ionic liquid than in toluene. Some of the findings were attributed by the authors to the lower gas solubility in the ionic liquid and the slower diffusion of the reactive gases H2 and CO into the ionic medium. 

A very important general aspect of hydroformylation catalysis is the fact that the regioselectivity of the reaction is usually of great importance for the economic value of the generated products. Typically, the linear product enjoys a much higher market value than the branched one. This point can be exemplified for both the hydroformylation of propene and that of 1-dodecene. While the lower vapor pressure of the resulting plasticizer alcohol defines the higher... 

The ionic compounds 1,2,3-trimethylimidazolium triflate and l-ethyl-2,3-dimethylimidazolium trifiate and the coordination compound (3-butylimidazole) triphenylboron were used as solvents for biphasic rhodium-catalyzed hydroformylation of 1-hexene and 1-dodecene. High conversions with varying linear/branched aldehyde ratios were observed. Compared to the conventional solvent toluene, similar turnover numbers, but a higher tendency toward isomerization and hydrogenation, were found [96]. 

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