Ruhrchemie process development

Hydroformylation of Other Lower Olefins and Dienes - Lower olefins such as 1-butene or 1,3-butadiene are hydroformylated with acceptable rates using Rh/tppts catalysts according to the RCH/RP process. Hoechst AG Werk Ruhrchemie has developed an attractive new process350 for the hydroformylation of raffinate II, a mixture of 1-butene, cis- and /rbutane derived from the C4 stream of naphtha crackers (after removal of 1,3-butadiene... 

Table V shows the salient features of several Fischer-Tropsch processes. Two of these—the powdered catalyst-oil slurry and the granular catalyst-hot gas recycle—have not been developed to a satisfactory level of operability. They are included to indicate the progress that has been made in process development. Such progress has been quite marked in increase of space-time yield (kilograms of C3+ per cubic meter of reaction space per hour) and concomitant simplification of reactor design. The increase in specific yield (grams of C3+ per cubic meter of inert-free synthesis gas) has been less striking, as only one operable process—the granular catalyst-internally cooled (by oil circulation) process—has exceeded the best specific yield of the Ruhrchemie cobalt catalyst, end-gas recycle process. The importance of a high specific yield when coal is used as raw material for synthesis-gas production is shown by the estimate that 60 to 70% of the total cost of the product is the cost of purified synthesis gas.

A further development of this successful technology was achieved to take advantage of the available feedstock base of butene isomers (raffinate II) for the preparation of n-C5 products (n-valeraldehyde, n-isoamyl alcohol, and n-valeric acid). In December 1995 production of n-valeraldehyde was started up in a new plant at Hoechst/Ruhrchemie (138). Generally, there are strong restrictions in the application of the two-phase catalytic processes to higher alkenes (Section IV.B.l), but the adaptation to butenes was possible with little modification of the process developed for propene. 

Water soluble ligands greatly facilitate catalyst separation. Examples are (22-XLI)174 and (22-XLII),175 which are used in hydroformylations and hydrogenation catalysis, respectively. Rhodium complexes of the sulfonated phosphine (22-XLI) are used in the production of butyraldehyde, a large-scale process developed by Ruhrchemie/Rhone-Poulenc.174... 

Catalyst decomposition is, overall, receiving little attention in academic work on homogeneous catalysis, and only in recent years has research on decomposition and stabilization of organometallic catalysts started to expand (116), with emphasis on reactions of significant commercial interest such as hydroformylation (117), metathesis 118), crosscoupling, and polymerization 119). Ligand decomposition seems to be a key issue for industrial application, because it affects the total number of turnovers, TON. Phosphine decomposition is an unavoidable side reaction in metal-phosphine complex-catalyzed reactions and the main barrier for commercial application of homogeneous catalysts. There are a few exceptions to this statement for example, the rhodium tppts-catalyzed hydroformylation of propene, a process developed by Ruhrchemie-Rhone Poulenc (now Celanese). 

The studies by Job and Kuntz had a pecufiar fate. It may well have been due to the remoteness from practice and the lack of incentive for new variants of hydrogenation processes that Job s work almost became lost in the academic world. Likewise, the importance of the prefiminary work of Kuntz was recognized neither by his own company nor by the academic community, which may well be attributed to the fact that the results were recorded in patents and academic teachers and researchers are reluctant to take notice of such apocryphal literature. There was therefore a need for an industrial impetus and the readiness to carry out process development work based on these studies. This occurred after 1982 in collaborative work between Ruhrchemie AG and Rh6ne-Poulenc (RCH/RP) [26]. The combination of a basic idea from Rh6ne-Poulenc with the competence of a team at the then Ruhrchemie AG with ex-... 

With only one exception, all industrially applied oxo processes more or less follow the technique which was developed by Ruhrchemie AG in Oberhausen/Germany [895-898, 1015] in co-operation with BASF. The exception is the process developed by Shell, which will be discussed later. The first industrial application dates back to 1940 when plant operations were started in the works of Ruhrchemie by a joint venture of Ruhrchemie, BASF and Henkel. 

Fig. 20. Homogeneous rliodium-cataly2ed oxo process in biphasic media developed by Ruhrchemie/Rhc ne-Poulenc (83).

In the mid-1980s, Ruhrchemie (now Hoechst) converted its oxo capacity to a proprietary water soluble rhodium catalyzed process (27,28), a technology developed jointly with Rhc ne-Poulenc. Product separation in this process is by decantation. Isomer ratios of n- to isobutyraldehyde of about 20 1 are obtained. 

Although rhodium recovery is efficient it is difficult to separate it from heavies that are formed in small amounts. Over time these heavies tend to result in some catalyst deactivation. One solution to this problem has been developed by Ruhrchemie/Rhone-Poulenc. In this process sulfonated triphenyl phosphine is used as the ligand, which imparts water solubility to the catalyst. The reaction is two-phase, a lower aqueous phase containing the catalyst and an upper organic phase. Fortunately the catalyst appears to sit at the interface enabling reaction to proceed efficiently. At the end of... 

Biphasic techniques for recovery and recycle are among the recent improvements of homogeneous catalysis - and they are the only developments which have been recently and successfully applied in the chemical industry. They are specially introduced into the hydroformylation (or "oxo") reaction, where they form a fourth generation of oxo processes (Figure 5.1 [1]). They are established as the "Ruhrchemie/Rhone-Poulenc process" (RCH/RP) [2] cf. also Section 5.2.4.1), with annual production rates of approximately 800,000 tonnes y"1 (tpy). 

RCH [Ruhrchemie] A process for increasing the octane rating of gasolines by catalytic isomerization of the olefin fraction, the double bonds migrating from the terminal positions. Developed by Ruhr Chemie in the 1940s. 

The synthesis of aldehydes via hydroformylation of alkenes is an important industrial process used to produce in the region of 6 million tonnes a year of aldehydes. These compounds are used as intermediates in the manufacture of plasticizers, soaps, detergents and pharmaceutical products [7], While the majority of aldehydes prepared from alkene hydroformylation are done so in organic solvents, some research in 1975 showed that rhodium complexes with sulfonated phosphine ligands immobilized in water were able to hydroformylate propene with virtually complete retention of rhodium in the aqueous phase [8], Since catalyst loss is a major problem in the production of bulk chemicals of this nature, the process was scaled up, culminating in the Ruhrchemie-Rhone-Poulenc process for hydroformylation of propene, initially on a 120000 tonne per year scale [9], The development of this biphasic process represents one of the major transitions since the discovery of the hydroformylation reaction. The key transitions in this field include [10] ... 

A few years later, Ruhrchemie joined forces with Rhone-Poulenc to develop a continuous biphasic hydroformylation process since Rhone-Poulenc had no... 

A very elegant solution to solve this problem is the introduction of either a permanent or a temporary phase boundary between the molecular catalyst and the product phase. The basic principle of multiphase catalysis has already found implementation on an industrial scale in the Shell higher olefin process (SHOP) and the Ruhrchemie/Rhdne-Poulenc propene hydroformylation process. Over the years, the idea of phase-separable catalysis has inspired many chemists to design new families of ligands and to develop new separation... 

In 1975 Kuntz has described that the complexes formed from various rhodium-containing precursors and the sulfonated phosphines, TPPDS (2) or TPPTS (3) were active catalysts of hydroformylafion of propene and 1-hexene [15,33] in aqueous/organic biphasic systems with virtually complete retention of rhodium in the aqueous phase. The development of this fundamental discovery into a large scale industrial operation, known these days as the Ruhrchemie-Rhone Poulenc (RCH-RP) process for hydroformylation of propene, demanded intensive research efforts [21,28]. Tire final result of these is characterized by the data in Table 4.2 in comparison with cobalt- or rhodium-catalyzed processes taking place in homogeneous organic phases. 

There are many important points and lessons to be learned from the development and operation of the Ruhrchemie-Rhone Poulenc process and we shall now have a look at the most important ones. 

A breakthrough in the hydroformylation of propene was achieved following the synthesis of the water soluble ligand tppts for the preparation of the RhH(CO)(tppts)3 catalyst345 which formed the basis for the development of the Ruhrchemie/Rhone-Poulenc two phase process. This process operates under mild reaction conditions giving excellent n/i ratios and easy separation of products from the catalyst by decantation with virtually no catalyst leaching. 

Hydroformylation of Propene the Ruhrchemie/Rhone-Poulenc (RCH/RP) Process - The industrial process for the hydroformylation of propene in a two phase system was developed by Ruhrchemie AG after a period of successful scale up tests in pilot plants.31 34 35-38-42 48 50 52-57 61 64-6 70-7 74,132-134,224,307.322,323,... 

Prewar Development of Synthesis Operation in Germany. The production of significant quantities of liquid hydrocarbons from synthesis gas over a cobalt catalyst was first reported by Fischer and Tropsch (6) in 1926. In 1932 a catalyst, useful for commercial operations, was described by Fischer and Koch (4), and in 1935 Ruhrchemie built the first full scale synthesis plant, which operated, at atmospheric pressure. In 1936, the process was modified by the work of Fischer and Pichler (5) to operate at. 5 to 15... 

In the Fischer-Tropsch process, as developed commercially by the Ruhrchemie A.G. in Germany (30) in 1935-40, synthesis gas containing 2 volumes of hydrogen per volume of carbon monoxide was compressed to about 7 atmospheres and passed through a granular... 

An important development in the past 15 years in hydroformylation technology was the introduction of biphasic homogeneous catalysis. Kuntz (62) expressed the basic idea of a new generation of water-soluble oxo catalysts with triphenylphosphane trisulfonate (tppts as the sodium salt) as a ligand for a rhodium-complex-catalyzed hydroformylation process. Ruhrchemie AG adapted the idea on the basis of research done at Rhone-Poulenc and developed it into an industrially viable process, which was... 

The history of aqueous industrial two-phase catalysis began in 1984 when the hydroformylation of propene in water was first carried out in the plants of Ruhrchemie AG. The development of the aqueous two-phase process was completely atypical in that the initial research work was done by Rhone-Poulenc but the development work was done by the former Ruhrchemie (today part of Hoechst AG). A rather long time elapsed before further fundamental work was begun in academic laboratories. 

Three commercial homogeneous catalytic processes for the hydroformyla-tion reaction deserve a comparative study. Two of these involve the use of cobalt complexes as catalysts. In the old process a cobalt salt was used. In the modihed current version, a cobalt salt plus a tertiary phosphine are used as the catalyst precursors. The third process uses a rhodium salt with a tertiary phosphine as the catalyst precursor. Ruhrchemie/Rhone-Poulenc, Mitsubishi-Kasei, Union Carbide, and Celanese use the rhodium-based hydroformylation process. The phosphine-modihed cobalt-based system was developed by Shell specih-cally for linear alcohol synthesis (see Section 7.4.1). The old unmodihed cobalt process is of interest mainly for comparison. Some of the process parameters are compared in Table 5.1. 

---