IFP-Dimersol

The process involves reacting butenes and mixtures of propenes and butenes with either a phosphoric acid type catalyst (UOP Process) or a nickel complex-alkyl aluminum type catalyst (IFP Dimersol Process) to produce primarily hexene, heptene, and octene olefins. The reaction first proceeds through the formation of a carbocation which then combines with an olefin to form a new carbocation species. The acid proton donated to the olefin initially is then released and the new olefin forms. Hydrotreatment of the newly formed olefin species results in stable, high-octane blending components. 

A wide range of processes is available in the area of oligomerization applicable to C4. olefins. However, a distinction must be drawn between those intended for the effective manufacture of the higher olefinic hydrocarbons, which operate either in a bomogeneoos phase (Bayer, IFP Dimersol), or in a heterogeneous phase (IFP Polynapbta, Petrotex, UOP), which were discussed in Section 2.3.3.2, and those that are only intended to facilitate subsequent treatment... 

The IFP Dimersol Process for Dimerization of Propylene into Isohexenes... 

Chauvin, Y, Gaillard, J.F. Quang, D.V. Andrews J.A. " The IFP Dimersol Process for the Dimerization of C3 6e C4 Olefinic Cuts NPRA Convention Center, San Antonio, Texas, (1973)... 

The hydroformylation of mixtures of Cg-olefins is a process with huge economic importance. A typical example is di-n-butene, consisting of isomeric -octenes, methylheptenes, and dimethylhexenes. The mixture is produced from Raffinate II, in which isomeric butenes are dimerized (e.g., by IFP Dimersol [47] or Octol process [48]). Hydroformylation of di- -butene produces linear and alkyl-branched Cg-aldehydes, which are converted to diisononyl phthalate (DINP), another additive for flexible PVC with immense industrial relevance. For this application, the use of terminal aldehydes is preferred. 

The IFP dimersol process (Dimersol G) for the single-stage dimerization of propylene yields hexenes present in high-octane gasoline [583,584]. The process takes place under the rigorously controlled conditions of reduced pressure and ambient temperature in the presence of catalytic amounts of a nickel and aluminum alkyl complex, which is immediately destroyed in an NHj—HjO system upon completion of the dimerization. 

Similar to IFP s Dimersol process, the Alphabutol process uses a Ziegler-Natta type soluble catalyst based on a titanium complex, with triethyl aluminum as a co-catalyst. This soluble catalyst system avoids the isomerization of 1-butene to 2-butene and thus eliminates the need for removing the isomers from the 1-butene. The process is composed of four sections reaction, co-catalyst injection, catalyst removal, and distillation. Reaction takes place at 50—55°C and 2.4—2.8 MPa (350—400 psig) for 5—6 h. The catalyst is continuously fed to the reactor ethylene conversion is about 80—85% per pass with a selectivity to 1-butene of 93%. The catalyst is removed by vaporizing Hquid withdrawn from the reactor in two steps classical exchanger and thin-film evaporator. The purity of the butene produced with this technology is 99.90%. IFP has Hcensed this technology in areas where there is no local supply of 1-butene from other sources, such as Saudi Arabia and the Far East. 

Dimersol A family of processes for dimerizing single or mixed olefines, catalyzed by mixtures of trialkyl aluminum compounds and nickel salts. Developed by IFP and first commercialized in 1977 by 1997 it was used in 26 plants. 

Dimersol E A process for making gasoline from ethylene. The catalyst is a soluble Ziegler-type catalyst containing nickel. Developed by IFP in the 1980s and operated at an undisclosed location since 1988. 

Dimersol G A process for dimerizing propylene to a mixture of isohexenes, suitable for blending into high-octane gasoline. The process is operated in the liquid phase with a dissolved homogeneous catalyst. Developed by IFP and first operated at Alma, MI, in 1977. 

Dimersol X A process for dimerizing mixed butenes to mixed octenes. Selective hydrogenation, catalyzed by a soluble Ziegler catalyst, is used. The spent catalyst is discarded. The process was developed by IFP and first operated at Kashima, Japan, in 1980. BASF has used the process in Ludwigshafen since 1985. 

The soluble nickel catalyst developed by IFP for the oligomerization of alkenes applied in different Dimersol processes (see Section 13.1.3) can also be used in benzene hydrogenation to replace Raney nickel (IFP cyclohexane process).340... 

Dimerization of propylene and butenes is also accomplished commercially to produce valuable motor gasoline components. IFP s Dimersol G process86-88... 

Difasol An improvement on the Dimersol process for dimerizing propene or butenes. The process utilizes an ionic liquid based on imidazoliniumaluminate and a nickel-based Dimersol catalyst. Developed by IFP in 1999, but not commercialized by 2005. 

IFP Octene Butenes Dimersol-X uses low investment, low-operating cost liquid-phase homgenous cataysis to make octenes with low braching 5 1997... 

The range of homogeneous reactions that has been transposed into ILs is probably wider than into SCCO2 or perfluorinated solvents due to the great versatility of ILs. However, most of these reactions are limited to laboratory- or bench-scale with just a few examples of pilot-scale. A relevant industrial example is the Difasol process, which can be seen as an extension of the Dimersol family of processes developed by IFP [94] ... 

This process, using the ionic liquid solvent system, has been commercialized by IFP, as the Difasol process. In this process butene is dimerized in a continuous two-phase procedure with high conversion of olefin and high selectivity to the dimer (Figure 2.9). Catalyst consumption is divided by a factor of about ten and a higher yield of dimers is obtained. Most important, the Difasol system can be retro-fitted into existing Dimersol plants to give improved yields, lower catalyst consumption and associated costs and environmental benefits. 

Ni-catalyzed dimerization of propene and/or butenes, which was intensively studied in the 1960 s [96] and later commercialized as the Dimersol process by the Institut Franjais du Petrole (IFP). The active catalytic species is formed in situ through the reaction between a Ni(II) source and an alkylaluminium co-catalyst. 

From these results, the Institut Fran ais du Petrole (IFP) has developed a biphasic version of its established monophasic Dimersol process , which is offered for licensing under the name Difasol process [98]. The Difasol process uses slightly acidic chloroaluminate ionic liquids with small amounts of alkylaluminiums as the solvent for the catalytic nickel center. In comparison to the established Dimersol process , the new biphasic ionic liquid process drastically reduces the consumption of Ni-cata-lyst and alkylaluminiums. Additional advantages arise from the good performance obtained with highly diluted feedstocks and the significantly improved dimer selectivity of the Difasol process (for more detailed information see Section 5.3). 

Commercially viable oligomerization processes utilizing homogeneous nickel based catalysts are operating on a large scale. Two of particular interest in the present context are Shell s Higher Olefin Process (SHOP) (refs. 1-3) and IFP (Institut Francais du Petrole) Dimersol Process (refs. 4,5). 

In the mid-1970s, IFP developed such a process the Dimersol system. The homogeneous catalytic unit can be set out in difierent maimers inside refinery and petrochemical complexes, depending on the available feedstock and desired products... 

IFP [(Institut Francais du Petrole)—Axens] was the first to operate an ionic liquid pilot plant [43]. Since the mid-1970s, IFP developed the Dimersol process (Dimersol-G, and -X) that upgrades light olefins by dimerization (respectively, propene and butenes) to the more valuable branched hexenes and octenes, respectively in high yield (Figs. 20.16 and 20.17) [44]. 

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