Alfen process

In the two-step Alfen process stoichiometric amounts of triethylaluminum are used, which have to be recovered in an additional process step before being reintroduced. 

The Alfen process can also be conducted as a single-step process the growth and displacement reactions occur simultaneously in the same reactor at 200°C and 250 bar ethylene pressure with catalytic amounts of triethylaluminum. 

The catalytic single-step Alfen process has a good space-time yield, and the process engineering is simple. The molecular weight distribution of the olefins of the single-step process is broader (Schulz-Flory type of distribution) than in the two-step Alfen process (Poisson-type distribution) (Fig. 2). As a byproduct 2-alkyl-branched a-olefins also are formed, as shown in Table 6. About... 

In the peaking process of the Ethyl Corporation, the catalytic single-step process and the stoichiometric two-step process are combined. The result is an olefin mixture with a narrowed molecular weight distribution [25]. In this combined process low molecular weight olefins (preferably n-butene-1) obtained by a single-step process are used as displacement olefins (instead of ethylene) in the second step of the stoichiometric two-step Alfen process. Table 7 shows the composition of an olefinic mixture produced by the combination process of the Ethyl Corporation. The values in Table 7 show that the olefin mixtures of the... 

FIG. 2 Molecular weight distribution in the homologous a-olefin mixtures of the single-step and two-step Alfen process, x —x, Single-step reaction O—O, two-step reaction. 

The molecular weight distribution of the obtained homologous fatty alcohols corresponds with a relatively narrow Poisson distribution and equals the molecular weight distribution of the olefins in the two-step Alfen process [38a]. 

The first process which allowed the industrial oligomerization of ethylene was developed hy Ziegler in the early 1950s [1]. In the two-step Alfen process, the chain-growth reaction is first accomplished at about 100 °C and 10 MPa ethylene pressure (eq. (2)). 

A derivative of the Ziegler ethylene polymerization process (Alfene process producing 2-linear olefins), this technique is used to produce high molecular weight linear alcohols with an even number of carbon atoms (C4 to C2 -). It was developed by Continental Oil Company, and employs the growth reaction of polyethylene from triethytahinrimim. The rupture of the chain is caused by oxidation of the product ... 

Alfene [Alfa olefene] Also spelled Alfen. A process for making higher alpha-olefins. Ethylene is reacted with triethyl aluminum, yielding high molecular weight aluminum alkyls, and these are treated with additional ethylene, which displaces the higher olefins. Developed by the Continental Oil Company. 

Miller, S. Alfene and Allol processes", Chem. and Process Engng, 50 (10) 103-106 (1969)... 

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