Ruhrchemie/Rhone-Poulenc’s

The hydroformylation reaction is highly exothermic, which makes temperature control and the use of the reaction heat potentially productive and profitable (e.g, steam generation). The standard installation of Ruhrchemie/Rhone-Poulenc s aqueous-phase processes is heat recovery by heat exchangers done in a way that the reboiler of the distillation column for work-up of the oxo products is a falling film evaporator... 

Figure 5.8 Flow sheet of Ruhrchemie/Rhone-Poulenc s process.

In UCC s low-pressure and Mitsubishi Kasei oxo processes the reaction products (isononyl aldehyde, etc.) are separated by distillation from the catalyst phase. As already mentioned, in the Ruhrchemie/Rhone-Poulenc s hydrofor-mylation process, the aqueous phase containing the catalyst is removed after the reaction from the organic phase by decantation. Also in this process, the heat from the oxo reaction is recovered in a falling film evaporator incorporated inside the reactor, which acts a reboiler for the /i- butanal/isobutana I distillation column. 

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.

An excellent example of sustainable chemical processes using homogeneous catalysts is Ruhrchemie/Rhone-Poulenc s (RCH/RPs) oxo process, which is a prototype of an aqueous biphasic process (Figure 2.3) [65, 66]. The first commercial oxo plant using the RCH/RPs biphasic process went on stream in 1984 and has produced over 5 million tons of n-butanyraldehyde (as well as less than 4% iso-butyraldehyde). 

The environmental aspects of the aqueous biphasic processes have been intensively studied and discussed taking Ruhrchemie/Rhone-Poulenc s oxo process as... 

Why multiphase systems. This goes back to the 1980s and the enormous impetus which was given to the homogeneous catalysis community by the first realization of Ruhrchemie/Rhone-Poulenc s oxo process at the Oberhausen plant site. Astonishingly, it was this development (and not the earlier SHOP process of Shell) that sensitized the scene to the possibilities of multiphase action only on the basis of the aqueous activities that so much widespread and multi-faceted research work, with effects on the newer areas mentioned has been accomplished success-... 

Commercially, the aqueous-phase concept was firstly applied in Ruhrchemie/Rhone-Poulenc s (RCH/RP) process (for the fundamentals, see Section 2.4.1.1). In several units the RCH/RP process has been converting propene to n-butyraldehyde and isobutyraldehyde (or butenes to valeraldehydes) since 1984 in the presence of HRh(CO)(TPPTS)3 (with TPPTS = m-trisulfonated triphenylphosphine or tris-(sodium-fn-sulfonatophenyl)phosphine as water-soluble ligand) according to Eq. (1). The output of the units mentioned is approximately890 000 tpy, which corresponds to roughly 13% of the world s total production. 

Accompanying Ruhrchemie/Rhone-Poulenc s industrial realization of the aqueous biphasic hydroformylation reaction (cf Sections 2.4.1.1.3 and 2.5.1) and Kuraray s hydrodimerization process (see Section 2.4.4.2), there are some other minor processes for the production of fine chemicals. 

Using such a catalytic system implies identifying a solvent that can achieve selective catalyst solubilization, with no impact on its activity. Two of these solvents are now used in industrial liquid-liquid biphasic catalytic processes butane-1,4-diol in Shell s SHOP oligomerization process and water in Ruhrchemie/Rhone-Poulenc s olefin hydroformylation process. 

The processes are ordered within the Tables according to their industrial relevance, starting with the two commercial processes — Ruhrchemie/Rhone-Poulenc s oxo process and the SHOP process of Shell [5]. As has been described in the preceding chapters, all other developments are more or less proposals rather than processes they are on the way from laboratory scale to first pilot plant apphcations and finally to industrial scale — some are in an advanced stage of realization, such as the Difasol process of IFP, BASIL of BASF, or Swan s TMCH process. For both tables, the degree of reahzatiorf depends on a few criteria, but decisive ones, which will be discussed below. 

The most important large-scale aqueous-organic biphasic process is the hydroformylation of propene into butanal (Scheme 14) catalyzed by [HRh(CO)-(TPPTSlsl, that is the Ruhrchemie-Rhone Poulenc process (63,139,140). The catalyst is dissolved in water, whereas the substrate and product(s) comprise the organic phase. In the heart of this technology is a continuously stirred tank reactor connected to a phase separator. Complete insolubility of the rhodium-phosphine catalyst in the organic phase together with the lack of surfactant behavior of TPPTS assures a full recovery of rhodium by perfect phase separation. The catalytic reaction takes place at 120°C and 5 MPa (CO H2 = 1.01 1)—such conditions are milder than those of the so-called low pressure oxo processes. Propene reacts... 

With optimized process operation the reaction is strongly regioselective. The process is commercialized by Rhone-Poulenc using Ruhrchemie s TPPTS and yields precursors for vitamin E cf. Section 3.1.1.1.3 [163, 164] Sc or Y triflates catalyze aqueous biphasic reactions which are alternatives to base-catalyzed processes such as aldol or Michael-type conversions [257]. 

In total, RCH/RP s process - although neither company still exists Ruhrchemie went its way through Hoechat AG and Celanese to the present owner Blackstone and the j oint venture European Oxo Rhone-Poulenc became a part of the late Aventis SA and now Sanofi - is still the only oxo version of the fifth-generation hydroformylation processes. 

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