Olefins ethylene oligomerization

Butene. Commercial production of 1-butene, as well as the manufacture of other linear a-olefins with even carbon atom numbers, is based on the ethylene oligomerization reaction. The reaction can be catalyzed by triethyl aluminum at 180—280°C and 15—30 MPa ( 150 300 atm) pressure (6) or by nickel-based catalysts at 80—120°C and 7—15 MPa pressure (7—9). Another commercially developed method includes ethylene dimerization with the Ziegler dimerization catalysts, (OR) —AIR, where R represents small alkyl groups (10). In addition, several processes are used to manufacture 1-butene from mixed butylene streams in refineries (11) (see BuTYLENEs). 

Shell Higher Olefins Process (SHOP). In the Shell ethylene oligomerization process (7), a nickel ligand catalyst is dissolved in a solvent such as 1,4-butanediol (Eig. 4). Ethylene is oligomerized on the catalyst to form a-olefins. Because a-olefins have low solubiUty in the solvent, they form a second Hquid phase. Once formed, olefins can have Htfle further reaction because most of them are no longer in contact with the catalyst. Three continuously stirred reactors operate at ca 120°C and ca 14 MPa (140 atm). Reactor conditions and catalyst addition rates allow Shell to vary the carbon distribution. 

These detergent range (C C ) odd and even linear internal olefins are fed to oxo-alcohol plants to produce C22 C2 semilinear alcohols. Most of the alcohols are ethoxylated and sold into detergent markets (8). Shell balances carbon numbers by a combination of the ethylene oligomerization extent. 

In addition to the neutral nickel/phosphine complexes used in the Shell Higher Olefins Process (SHOP), cationic Ni-complexes such as [(mall)Ni(dppmo)][SbF6] (see Figure 5.2-7) have attracted some attention as highly selective and highly active catalysts for ethylene oligomerization to HAOs [106]. 

Homologous even-numbered n-a-olefins by oligomerization processes of ethylene... 

Coordination-catalyzed ethylene oligomerization into n-a-olefins. The synthesis of homologous, even-numbered, linear a-olefins can also be performed by oligomerization of ethylene with the aid of homogeneous transition metal complex catalysts [26]. Such a soluble complex catalyst is formed by reaction of, say, a zero-valent nickel compound with a tertiary phosphine ligand. A typical Ni catalyst for the ethylene oligomerization is manufactured from cyclo-octadienyl nickel(O) and diphenylphosphinoacetic ester ... 

The oligomerization of the ethylene is performed at 80-120°C and at a pressure of 70-140 bar. A solvent like 1,4-butanediol is used, in which only the catalyst and the monomeric ethylene are soluble but not the formed higher molecular weight olefins. The oligomerization of the ethylene in such a two-phase systems enables the separation of the homogeneous catalyst from the reaction product by a simple phase separation. 

Apart from the UOP Pacol process, today s only other meaningful economic process is the Shell higher olefin process (SHOP) in which /z-olefins are produced by ethylene oligomerization. Until 1992 Hiils AG used its own technology to produce -60,000 t/year of /z-olefins by the chlorination of /z-paraffins (from Molex plant) and subsequent dehydrochlorination [13]. In the past, the wax cracking process (Shell, Chevron) played a certain role. In the Pacol and Hiils processes, olefins are obtained as diluted solutions in paraffin (Pacol to max. 20%, Hiils about 30%) without further processing these are then used for alkylation. In contrast, the SHOP process produces pure olefins. 

Nickel containing MCM-36 zeolite was used as new catalyst in the ethylene oligomerization reaction performed in slurry semi-batch mode. This catalyst, with micro-mesoporous structure, mild acidity and well balanced Ni2+/acid sites ratio, showed good activity (46 g of oligomers/gcataLh) and selectivity (100% olefins with even number of carbon atoms). The NiMCM-36 behaviour was compared to those obtained with NiMCM-22, NiY, NiMCM-41 and NiMCM-48 catalysts. 

SHOP [Shell Higher Olefins Process] A process for producing a-olefins by oligomerizing ethylene, using a proprietary rhodium/phosphine catalyst. The a-olefins can then be iso-merized to internal olefins as required. Invented by W. Keim in the Institut fur Technische Chemie und Petrolchemie, Aachen, in the 1970s. The first plant was built in Geismar, LA, in 1979 the second in Stanlow, Cheshire, in 1982. Licensed worldwide by a consortium of Union Carbide, Davy-McKee, and Johnson Matthey. 

Properties and handling. Typical properties for the alpha olefins produced by ethylene oligomerization are given in Table 21-4. You can find in the table that as the carbon count increases, purity declines. The impurities are branched chains and internal olefins (beta, gamma, etc.) These variations have more opportunity to form as the molecules get longer—Murphys Third Law in operation again. 

Alkenes. At present alkene isomerization is an important step in the production of detergent alkylates (Shell higher olefin process see Sections 12.3 and 13.1.3).264 265 Ethylene oligomerization in the presence of a nickel(O) catalyst yields terminal olefins with a broad distribution range. C4-C6 and C2o+ alkenes, which are not suitable for direct alkylate production, are isomerized and subsequently undergo metathesis. Isomerization is presumably carried out over a MgO catalyst. 

Oligomerization of Ethylene. 1-Butene is a small by-product in the production of linear alpha-olefins by oligomerization of ethylene. Linear alpha-olefins have one double bond at the terminal position and comprise the homologous series of compounds with carbon atoms between 4 and 19. The primary use of alpha-olefins is in the detergent industry. About 245,000 t/yr of 1-butene was produced for chemical use in the Gulf Coast of the United States in 1988 (72). 

Chevron-Gulf process -ethylene oligomerization [OLEFINS, HIGFIER] (Vol 17)... 

Addition. Addition reactions of ethylene have considerable importance and lead to the production of ethylene dichloride, ethylene dibromide, and ethyl chloride by halogenation—hydrohalogenation ethylbenzene, ethyltoluene, and aluminum alkyls by alkylation a-olefins by oligomerization ethanol by hydration and propionaldehyde by hydroformylation. 

Wasserscheid, P., Hilgers, C., and Keim, W. (2004) Ionic liquids -weakly-coordinating solvents for the biphasic ethylene oligomerization to alpha-olefins using cationic Ni-complexes./. Mol. Catal. A - Chem., 214 (1), 83-90. 

Aluminum alkyls used in making organometallic catalysts and as initiators for processes such as ethylene-propylene rubber, polybutadiene, low-pressure polyethylene, and ethylene oligomerization to make alpha-olefins and C6-C18 alcohols... 

Linear internal monoolefins can be oxidized to linear secondary alcohols. The alpha (terminal) olefins from ethylene oligomerization, described earlier in this chapter, can be converted by oxo chemistry to alcohols having one more carbon atom. The higher alcohols from each of these sources are used for preparation of biodegradable, synthetic detergents. The alcohols provide the hydrophobic hydrocarbon group and are linked to a polar, hydrophilic group by ethoxylation, sulfation, phosphorylation, and so forth. 

Probably the first example of a process employing the biphasic concept is the Shell process for ethylene oligomerization in which the nickel catalyst and the ethylene reactant are dissolved in 1,4-butanediol, while the product, a mixture of linear alpha olefins, is insoluble and separates as a second (upper) liquid phase (see Fig. 7.1). This is the first step in the Shell Higher Olefins Process (SHOP), the largest single feed application of homogeneous catalysis [7]. 

The chelate effect is important in the oxidative additions of P—C bonds which, in the case of nickel, give P—O and P—N chelate complexes of the type used as ethylene oligomerization catalysts in the Shell higher olefin process (SHOP),91 for example,... 

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