SHOP process

A key portion of the SHOP process is the isomerization—disproportionation (I/D) process in which excess light (C —C q) and heavy olefins (Cjg ) are converted to detergent range odd and even linear internal olefins. Eor each pass through this system, only 10—15% of the olefins fed are... 

Table 9 shows the composition of /i-i /-olefin mixtures obtained by the double-bond isomerization cometathesis reaction sequence of the SHOP process. 

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. 

Figure 5.12. Postulated mechanism for ethylene oligomerization according to Shell s SHOP process with a P,0-...

Figure 9.2. Simplified flow scheme of SHOP process...

From the Shell SHOP process to give linear even and odd numbered chains... 

Liquid/liquid extraction of the catalyst, as in the DuPont adiponitrile process, where the nickel complex is extracted out of the product mixture after the reaction, with a solvent (see Section 7.7). In Shell s SHOP process the soluble nickel catalyst is also extracted from the reaction medium with a highly polar solvent, and reused (see Section 7.4.1). 

Large-scale manufacturing processes involving isomerization reactions by homogeneous catalysts are few. Two important ones are the isomerization step in the SHOP process and the enantioselective isomerization of diethylgeranyl or diethylnerylamine as practiced by the Takasago Perfumery. The isomerization step in the SHOP process is discussed later on in this chapter. The Takasago process is discussed in Chapter 9. Isomerization of alkenes with nitrile functionalities is very important in DuPont s hydrocyanation process. The mechanism for this reaction is discussed in Section 7.7. 

Metathesis of alkenes is essentially a class of reactions where an interchange of C atoms between pairs of double bonds takes place. A few representative examples are shown by the reactions listed in Fig. 7.10. The industrial use of metathesis reactions so far has been limited mainly to exchange metathesis (Fig. 7.10, top, backward reaction) as in the SHOP process, and ring-open metathesis polymerization (ROMP). As already mentioned (Section 7.5), Vas-tenamer is a polymer made by Hulls by ROMP from cyclooctene. Similarly, the polymer from norborene by ROMP is manufactured by CdF Chemie and is sold by the trade name of Norsorex . 

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. 

Table 129 provides some ecoaomic data on the Phillips and Shell SHOP processes. Alpha>olefms data related to production, capacities and consumption in Western Europe, the United States and Japan in 1984 are given in Table 130. 

Ketz et al. synthesised a keto functionalised imidazolium salt using the standard protocol by reacting the appropriate N-aryl substituted imidazole with the respective keto halide [95], Their intention was to use the corresponding nickel(II) carbene enolate complex in olefin polymerisation reactions similar to the phosphino enolates in the SHOP process [1 ]. It proved difficult to prepare the intended precatalyst with only one carbene enolate ligand attached to the nickel centre. Initially, the homoleptic complex with two carbene enolate ligands was formed. The authors pointed out that the high proportion of n-olefins is unusual. 

Figure 5. Simplified flow diagrams for biphasic catalyses [16] (a) product(s) P is completely insoluble in the catalyst containing medium C - e. g., Ruhrchemie/Rhone-Poulenc s 0X0 process (b) P is soluble or partly soluble in C (c) the second phase is formed during the catalytic process - e. g.. Shell s SHOP process.

A metathesis similar to OCT came on stream about the same time as the SHOP process. Ethenolysis43 of a mixture of 2,4,4-trimethyl-2-pentene and 2,4,4-trimethyl-1-pentene yields 3,3-dimethyl-l-butene (commonly called neohexene) plus isobutylene (equation 11.15). 

The SHOP process, together with the previously discussed RCH/RP 0x0 process, are the two successful industrial processes cited as examples of the contribution... 

Figure 2.5 (a) Scheme of the SHOP process (b) flow-sheet of the oligomerization biphasic process. Source adapted from Hagen [60],... 

Vogt, D. (2005) Economical applications (SHOP process), in Multiphase Homogeneous Catalysis (eds B. Comils et al), Wiley-VCH Verlag, Weinheim,... 

The term biphasic catalysis has established itself only slowly, especially since the first commercial appHcations (by Shell in the SHOP process, [18]) named the process thus only tentatively (and in obviously rarely read patent apphcations). 

The Dimersol and SHOP processes demonstrate the commercial viability of homogeneous dligomerization catalysis in the fuels related and speciality chemicals areas. However there is a constant demand for improvement in aspects such as activity, selectivity control, process versatility, simplicity and i nnovativeness. 

D. Vogt, Nonaqueous Organic Organic Separation (SHOP Process), in Aqueous-Phase Organometallic Catalysts, B. Comits, W. A. Herrmann, Eds., pp. 639-645, Wiley-VCH, Weinheim, Germany, 2004. 

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