The use of Synthol High Temperature Fischer-Tropsch (HTF-T) pro"ducts as an inexpensive and alternative hydroformylation feedstock for producing Oxo alcohols has been investigated. These alcohols are precursors for biodegradable detergents. The HTF-T product targeted as a feedstock source was Synthol Light Oil (SLO}, in the Ca to C12 range. The aim of the work was to identify a suitable hydroformylation catalyst system for use with SLO feeds. Process variables such as feed composition, temperature, pressure and contact time were investigated. Emphasis was placed on the determination of feed-catalyst compatibility; the development of a "working" kinetic model on a batch micro-reactor scale; and extrapolation of the results to a continuous catalyst testing unit. An integral part of the work therefore involved characterization and quantification of these complex hydroformylation systems, as well as the development of methods to achieve this goal. Hydroformylation of various SLO fractions in the Ca to C12 range was undertaken. As a yardstick, the results were compared with those generated using pure 1-decene feed. The results obtained with pure feeds were duplicated, and in some cases improved upon when using SLO. The Ca_9 , C9 , C10 and C11 _12 single and double carbon number SLO fractions tested were prepared by distillation. This, apart from caustic washing to remove carboxylic acids, was demonstrated as the only step required to produce suitable hydroformylation feeds. Minimal cleanup of the feed was facilitated by the apparent "inertness" of non-olefinic components in SLO. These consist of various aromatics, oxygenates and paraffins. The olefins in SLO consist mainly of linear a-olefins, mono-methyl a-olefins and smaller quantities of internal olefins. Different olefin isomer distributions could be obtained by refractionation of the SLO. Feed, as well as resultant product compositions, could therefore be tailored according to the distillation procedures employed. Phosphine modified hydrocarbonyl rhodium and cobalt hydroformylation catalysts were screened. These experiments were undertaken with a view to maximizing product linearity and establishing feed - catalyst compatibility. In this regard, TriPhenylPhospine (TPP) ligand was tested with Rh and Tri-nButylPhosphine (TBP) as well as TPP ligands were tested with Co. Various so called heterogeneous catalysts based on Co were unsuccessfully evaluated. The RhffPP and CoffBP experiments were successful, but the Rh catalysts appeared more susceptible to poisoning. It was demonstrated that the unique character of the olefin composition and distribution in the HTF-T fractions could be exploited in n-alkylphosphine modified Co systems. These catalyst systems facilitate isomerization of a-olefins to internal olefins and interchange between internal and a-olefins occurs rapidly. Despite this however, the aldehydes and alcohols produced are predominantly linear because of the higher rate of hydroformylation of the a-olefins. It was shown that more internal olefins undergo hydroformylation in pure linear feeds compared with SLO feeds. This may be explained due to the methyl-branched internal olefins in SLO being thermodynamically favoured, but also being less reactive for hydroformylation compared with linear internal olefins. Because of the screening results, and the perceived difficulties in efficient recycling of Rh catalysts, further work concentrated on phosphine modified Co catalysts for the hydroformylation of SLO. This involved constant pressure "batch" experiments, and development of a system for quantifying olefins in the complex feeds. Emphasis was placed on testing and comparing results obtained with a "conventional" n'"alkylphosphine ligand and a bi-cyclic alkylphosphine ligand. The specific ligands under consideration were Tri-n-OctylPhosphine (TOP) and 9-Eicosyl-9-Phosphabicyclonane (EP). The following "standard" reaction conditions were selected based on the screening experiment results, and using reports in the literature as a guideline: Reaction temperature = 170°C; Pressure = 75 bar (g) constant; Syngas composition= 2:1 pure H2:CO; Molar ratio of phosphine: Co= 2:1; Stirrer speed · · = SOOrpm. The kinetics of olefin consumption for both pure linear and HTF-T product feed olefins of a single carbon number were shown to be approximately first order with respect to the olefin concentration. The rate was directly proportional to the . cobalt concentration. This first order relationship was relatively independent of the (methyl branched) : (linear) olefin ratio in the F-T feed. It was however demonstrated that longer olefins (for example C12 ) reacted more slowly than shorter olefins (for example C11 ). A kinetic expression describing the effect of carbon number and catalyst concentration on the rate of olefin consumption was derived for the Co/EP catalyst system. This expression was expanded to include the effect of temperature as well as syngas composition and pressure. Similar results were obtained with pure 2:1 H2:CO syngas, commercial syngas from an existing F-T facility, as well as syngas that had a 14% C02 content. On varying the H2:CO ratio in the syngas from 2:1 to 1 :2 and the total pressure from 45 to 90 bar (g), it was evident that reactions undertaken at 75 bar(g) with a H2:CO ratio of 2:1 were suitable for achieving high reaction rates coupled with satisfactory product linearity and catalyst stability. The catalyst systems were shown to be sensitive to temperature. Temperatures of around 185°C and higher resulted in Co/EP catalyst deactivation with concomitant precipitation of cobalt. This was ascribed to disintegration of the catalyst complex. The selected "standard" operating conditions therefore appeared to be in the correct regime. Based on the results in this study, coupled to the reported results of other workers, a theory on the effect of temperature in Co hydroformylation systems was proposed. The onset of catalyst deactivation was linked to the reaction rate and temperature and this was quantified. The hydroformylation activation energy (Ea) was calculated as being 99 kJ per mole for C10 , C,, and C,2 olefins in SLO with the Co/EP catalyst. This value is similar to values reported by other workers, who used different feeds and catalysts. The high value of Ea indicates that the system was free of diffusion constraints. The effect of an alkali modifier - namely potassium hydroxide (KOH) - was investigated for pure and HTF-T feeds. Contrary to reports in the literature, KOH did not appear to catalyse aldol condensation reactions with resultant heavy oxygenate formation at "standard" reaction conditions. Instead, the predominant heavier oxygenates were esters. These in turn were mostly formates formed as a result of CO incorporation into adsorbed alde~yde intermediates. The effect of KOH on Co/EP systems was more marked compared with Co/TOP. For the Co/EP systems, the KOH resulted in slower rates of reaction and appeared to have a similar effect to that of increasing the EP:Co ratio.

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