Olefins by oligomerization

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

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. 

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). 

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. 

One of the mam uses of the linear a olefins prepared by oligomerization of ethylene is in the preparation of linear low density polyethylene Linear low density polyethylene is a copoly mer produced when ethylene is polymerized in the presence of a linear a olefin such as 1 decene [H2C=CH(CH2)7CH3] 1 Decene replaces ethylene at random points in the growing polymer chain Can you deduce how the structure of linear low density polyethylene differs from a linear chain of CH2 units ... 

Manufacture of Monomers. The monomers of the greatest interest are those produced by oligomerization of ethylene (qv) and propylene (qv). Some olefins are also available as by-products from refining of petroleum products or as the products of hydrocarbon (qv) thermal cracking. 

The higher activity of the catalyst [(mall)Ni(dppmo)][SbFg] in [BMIM][PFg] (TOF = 25,425 h ) relative to the reaction under identical conditions in CFF2C12 (TOF = 7591 h ) can be explained by the fast extraction of products and side products out of the catalyst layer and into the organic phase. A high concentration of internal olefins (from oligomerization and consecutive isomerization) at the catalyst is known to reduce catalytic activity, due to the formation of fairly stable Ni-olefin complexes. 

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. 

De Klerk, A. 2006. Distillate production by oligomerization of Fischer-Tropsch olefins over solid phosphoric acid. Energy Fuels 20 439 -5. 

The catalytic transformation of olefins by transition metal complexes has received a great deal of attention during the past two decades. These catalytic reactions are important, especially industrially, because they represent some of the most economical ways to synthesize olefinic monomers or polymers. The more common types of these transformation reactions are (a) dimerization or polymerization of a-olefins (b) dimerization, oligomerization, cyclooligomerization, or polymerization of con-... 

Alpha olefins are made either by oligomerization, growing them on an aluminum root by adding ethylene until the desire size is reached, or by catalytic processes, one favoring the shorter alpha olefins. 

Double bond isomerization using molecular sieves (5A) was reported in the patent literature by Fleck and Wight of Union Oil Company [34] only a few years after synthetic zeolites became commercially available. More recently [35] ferrierite has also been claimed. The major initial uses were to convert a-olefins (1-olefins) into mixtures of internal olefins for further conversion, usually by oligomerization into various products-lube oil base stocks predominating. Inevitably, patents were issued noting the ability to convert internal olefins into mixtures containing greater concentrations of 1-olefins (e.g., [36]), but few practical processes have resulted. 

Linear hydrocarbons with a double bond at the end of the chain are made by oligomerization of ethylene. Compounds with 6-18 carbons are the most popular. Ziegler catalysts are used in this process. Note that certain olefins... 

In its commercial plants Sasol has to date used only iron based catalysts. (The preparation and properties of these catalysts have been reviewed elsewhere (2).) Not only is iron by far the cheapest of the metals (see Table I) but iron catalysts also produce large amounts of low molecular weight olefins which are important in the Sasol process. (These olefins are oligomerized to either gasoline or diesel fuel and this allows the production of these two liquid fuels to match the market requirement.) A major drawback of iron is that at high temperatures carbon deposition occurs which results in catalyst disintegration. 

Since isobutylene is a very reactive olefin, its oligomerization can be promoted by almost any electrophilic catalyst. More recently fluorinated alumina,6 cation-exchange resins,7 benzylsulfonic acid siloxane,8 pentasil zeolites,9 and perfluori-nated resinosulfonic acids10 were studied. Some of these catalysts may bring about improved oligomerization. 

Catani, R., Mandreoli, M., Rossini, S. and Vaccari, A. Mesoporous catalysts for the synthesis of clean diesel fuels by oligomerization of olefins. Catal. Today, 2002, 75, 125-131. 

Shell manufactures a-olefins from ethylene by oligomerization with a nickel catalyst in a polar solvent such as ethylene glycol, under the conditions specified in Equation 27. This corresponds to the first part of the SHOP process (Shell Higher Olefin Process) described in Section 6.2.2. The world production is estimated to be over 1 Mt/a. 

---