Catalyst testing procedure batch reactor

The C-5 sugar alcohols produced from the hydrolysis of hemicellulose are both xylitol and arabitol [6], Equivalence testing was performed with Ni/Re catalyst in the batch reactor to verily similar performance between xylitol and arabitol feedstocks. The operating conditions were 200°C and 8300kPa H2 using the procedure outlined in section Catalyst Screening section. 

The [YCo] systems catalyze this reaction only above 130°C, and hence, the reaction must be carried out in dilute benzene or toluene solutions to keep the TON values below —500. Only very active catalysts can be used for the reaction of Eq.(13) when carried out in pure acrylonitrile. Every cobalt catalyst sufficiently active below 125°C was tested in a batch reactor. A solution of the catalyst in pure acrylonitrile was saturated with acetylene at —2.0 MPa and then heated to 130°C (for experimental procedures, see 84MI5). The TON values after 2 hrs are summarized in Table II. The best results were obtained with the i7 -phenylborininato complex (9), which produced 2.78 kg VP/g Co. 

Reactions were carried out in liquid phase in a well-stirred (1000 rpm) high-pressure reactor (Parr Instruments, 300 mL) at 30 bar and 150°C. The reaction mixture consisted of 61 g of ADPA (Acros Chemicals), 53 g MIBK (Acros Chemicals) and 370 mg of catalyst. The test procedures used here is similar to that described earlier by Bartels et al. (7). The reactor was operated at a constant pressure with the liquid phase in batch mode and the hydrogen fed in at a rate proportional to its consumption. The reaction was monitored by hydrogen uptake and the product yield was determined from gas chromatographic (Agilent Technologies, 6890N) analysis. 

The value of catalyst testing is enhanced by reporting the results in a professional way. It is important to describe the following procedures Was a batch mode of operation or continuous, steady-state operation used What was the reactor configuration How were the catalysts prepared Was activation or pretreatment required ... 

The mathematical treatment of FMC data can be accomplished by standard procedures via the solution of mass balance equations, on condition that the data were converted to reaction rate data with Eq. (21). As mentioned above, this requires the determination of the transformation parameter a. Two approaches based on calibration were developed and tested. In the first approach, thermometric signals are combined with the absolute activity of IMB, which had been determined by a separate measurement using an independent analytical technique. Figure 5 shows a calibration for the cephalosporin C transformation catalyzed by D-amino acid oxidase. The activity of the IMB was determined by the reaction rate measurement in a stirred-tank batch reactor. The reaction rate was determined as the initial rate of consumption of cephalosporin C monitored by HPLC analysis. The thermometric response was measured for each IMB packed in the FMC column, and plotted against the corresponding reaction rate. From the calibration results shown in Fig. 5 it can be concluded, independently of the type of immobilized biocatalyst, that the data fall to the same line and that there is a linear correlation between the heat response and the activity of the catalyst packed in the column. The transformation parameter a was determined from... 

The experimental equipment and procedure used for the experimentation have been described [10]. A small visual cell reactor, 8 mL, was employed to visually check the solubility of the catalyst and the miscibility of reactants and products in SCCO2 at reaction conditions (Figure 2). Also, a 100 mL batch reactor with sampling on-line was installed to take samples at different times in order to determine the conversion and selectivity profiles against time (Figure 3). After each experiment the reactor was carefully washed and a blank test (without catalyst) was performed to ensure no catalyst was left in the reactor. 

Recycling experiments were performed to find the optimum conditions for a continuous flow process. Initially, the reactions were carried out in anhydrous benzonitrile. The reaction was terminated by filtration of the loaded support, which was then washed with benzonitrile and reused with a new batch of substrates. This procedure led to a dramatic loss of activity, for which the loss of palladium was not responsible but rather leaching of water into the organic phase. Thus, the mobility of the immobilized catalyst was reduced combined with a decrease of the activity. The use of benzonitrile/water (v/v=l/l) resulted in a constant level of activity. For a continuous flow experiment, a dry SAPC sample was prepared from Pd(OAc)2 and five equivalents of TPPTS. The dry support was then placed into a reactor. The required amount of water was transferred from water-saturated benzonitrile. The test reaction was the transformation of cinnamyl ethyl carbonate with morpholine. The process achieved a TON of 2,200 and worked continuously for approx. 12 h without loss of activity. 

The stability of the layered catalyst system was evaluated under typical conditions of the IMP upgrading process in a 5.2 month-long test (Alvarez et al., 2011). The study was carried out in another bench-scale plant with two fixed-bed reactors in series ( 900 cm of catalyst in each reactor), the scheme of which is similar to that shown in Figure 6.2 (Chapter 6). The total reactor volume was loaded with the same triple catalyst system that was used for generating the kinetic data and activated with the same procedure. The feedstock was essentially the same AR shown in Table 8.1, but with some slight differences as it came from another batch of 13°API HCO. 

---