Ethene oligomerization

Interestingly, the catalysts used here are similar to the nickel-ligand complexes used by Shell for their commercial ethene oligomerization process. Similar catalysts for making polyketone have also been patented by Keim et al. 

Jackson, K. J. and Howe, R. F. Studies of zeolite single crystals ethene oligomerization in HZSM-5. Stud. Surf. Sci. Catal., 1994, 83, 187-194. 

Nicolaides, C. P., Scurrell, M. S. and Semano, P. M. Nickel silica-alumina catalysts for ethene oligomerization - control of the selectivity to 1-alkene products. Appl. Catal., A, 2003, 245, 43-53. 

Fig. 16. FTIR spectra, recorded in fast acquisition conditions, showing the initial stages of the ethene oligomerization on H-ZSM-5. Spectra were recorded every 6.8 s (the last spectrum 19, corresponds to a total contact time of 130 s). The spectrum of gaseous ethene is shown at the bottom for comparison. Part (a) reports the v(CH3) and v(CH2) region, while part (b) reports the v(C = C), 5(CH3), and 5(CH2) region. The vibrational modes of CH3 and CH2 groups of the growing oligomers are drawn in full and dashed lines, respectively. The bands associated with ethene 71-complexes are indicated with dotted lines. (Adapted with permission from Spoto et al. (6).)...

Conversion and coke formation during catalytic ethene oligomerization catalyzed by HZSM-5 have been investigated in the TEOM and in a conventional gravimetric microbalance under similar conditions (2). The results show that the TEOM is a powerful tool for determination of the kinetics of deactivation of catalysts, with a design that makes determination of the true space velocity (or space time) easy. The TEOM combines the advantages of the conventional microbalance with those of a fixed-bed reactor, and the same criteria can be used to check for plug flow and differential operation. 

Example 10.4. Ethene oligomerization in the Shell Higher Olefin Process. The Shell Higher Olefin Process, abbreviated SHOP, produces predominantly internal straight-chain olefins in the C10 to C16 carbon-number range from ethene [107,109,119,120], Oligomerization of ethene to straight-chain 1-olefins of even carbon numbers is only... 

Examples include control of molecular weight in step-growth polymerization, number-average degree of polymerization in step-growth polymerization of nonstoichio-metric monomer mixtures, free-radical and anionic polymerizations of styrene, and ethene oligomerization to linear 1-olefins in the Shell Higher Olefins Process. 

Palladium Complexes with Bidentate Pn N-Ligands Application in Ethene Oligomerization 43... 

Palladium Complexes with Bidentate PnN-Ligands Application In Ethene Oligomerization... 

Several large-scale industrial processes use homogeneous catalysts [e.g., hydrofor-mylation, hydrocyanation (DuPont), ethene-oligomerization (SHOP), acetic add (Eastman Kodak), acetic acid anhydride (Tennessee-Eastman), acetaldehyde (Wacker) and terephthalic acid (Amoco)] as well as smaller scale applications [e.g., metolachlor (Novartis), citronellal (Takasago), indenoxide (Merck) and glycidol (ARCO, SIPSY)]. 

Some metal oxide catalysts are activated by thermal reduction with hydrogen or carbon monoxide. For example, the catalytic activity of molybdenum oxide and tungsten oxide for the metathesis reaction of olefins is very much enhanced by their slight reduction (1). The catalytic activity for butene isomerization and ethene oligomerization appears on niobium oxide by its... 

Oxide Catalysts ---- Ethene Oligomerization Activity Induced... 

Catalytic activity of niobium oxide for ethene oligomerization, photoinduced in the presence of various compounds. 

The catalytic activities for ethene oligomerization, induced by the photoreduction of niobium oxide with ethene and other various compounds at room temperature, are listed in Table 1. The catalysts photoreduced with H2 at room temperature and reduced thermally with H2 at 823K show comparable activity, but with much lower values than the catalyst photoactivated with ethene. Not only ethene but also other olefins are effective for the photoactivation. Low activation ability of 2,3-dimethyl-2-butene, however, has been observed, suggesting that vinyl hydrogen in olefins may play a role in the photoactivation. 

The same acidic chloroaluminate ionic liquids have been used as solvent for tungsten aryl oxide complexes for the metathesis of alkenes [24]. Slightly acidic chloroaluminates also dissolve the [Cl2W=NPh(PMe3)3] complex which catalyze ethene oligomerization without the addition of co-catalysts [25]. In a similar way, Ni-catalyzed 1-butene dimerization into linear octenes was carried out in acidic chloroaluminates buffered with small amount of weak bases [26]. Neutral chloroaluminates (l-ethyl-3-methylimidazolium chloride/AlCl3 = 1) were employed to immobilize ruthenium carbene complexes for biphasic ADMET (acyclic diene metathesis) polymerization of an acyclic diene ester [27]. 

Ion-exchanged catalyst is better for ethene oligomerization to diesel fuel, C10+ fraction in product was 41% vs. 23% for impregnated catalyst... 

Refs. [473,837,886,921]. Kustov et al. [922] published an interesting DRIFT spectroscopic study on ethene oligomerization, including a discussion of the role of Lewis- and Bronsted-acid sites and ethoxy groups as intermediates of this reaction. 

Table 3 Linear a-alkene capacities via ethene oligomerization.

The two operational SHOP sites today have a total capacity of nearly 1 million tons of a-alkenes per year. This is about one-half of the total amount made by oligomerization. Today linear a-alkenes are produced mainly by ethene oligomerization because of the high product quality and the good availability of ethene. The wide application and increasing need for short-chain a-alkenes as co-monomers for polymers cause the linear alkene market to continue growing. 

Scheme 7 Postulated mechanism for ethene oligomerization via a P O -stabilized nickel hydride...

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