Shell higher olefin process

The Shell Higher Olefin Process ( SHOP ) process is a chemical process for the production of linear α - olefins by ethene oligomerization, isomerization, and ethenolysis, which was invented and introduced by the Royal Dutch Shell. It is the first example of an industrially used heterogenization a homogeneous catalyst.

Implementation

In the first step, the ethene oligomerization takes place at temperatures from 80 to 120 ° C and a pressure of 70 to 140 bars ( 7-14 MPa). The reaction is effected with a nickel -phosphine complex of the type ( C6H5) 2P (CH2) 2- or 2COONi with Diphenylphosphinoessigsäure diphenylphosphinobenzoic acid catalyzed as a ligand. This step is carried out in a polar solvent such as 1,4 -butanediol. Since the formed α -olefins therein are not soluble, they can be easily separated. This produces a mixture of α -olefins, even with a Schulz -Flory distribution.

The C6 to C16 olefin fraction has a commercial value and is distilled off. Higher olefin fractions are first isomerized to 3, in a further step with a magnesium oxide catalyst at 80 to 120 ° C and up to 20 bar, to obtain olefins having internal double bonds. By metathesis with ethene these are catalytically converted into short-chain α - olefins. The process was introduced in 1977 and today has a capacity of approximately 10 million tons.

By combining oligomerization, isomerization and metathesis it geling so to convert almost the entire ethene is inserted into the desired product fractions.

The catalytic cycle

The process and its chemistry has been extensively studied in the research group of Professor Wilhelm Keim at RWTH Aachen, who is considered one of the key figures in the development of the process.

As an active catalyst applies the nickel hydride that is formed by cleavage of the cyclooctadiene ligand from the starting complex. By the insertion of ethylene into the nickel -hydrogen bond caused oligomers obtained by β - elimination of α -olefins of different chain lengths, but always with an even number of carbon atoms. It is believed that the Diphenylphospinoessigsäureligand affects the chain length distribution of the resulting olefins.