Equipment Microreactors

Temperature profile of the phenyl boronic acid synthesis along the major steps of the process flow scheme. The difference in the temperatures of the conventional batch and the microreactor processes stand for the reduction in energy consumption and respective heat-transfer equipment when using the latter [10]... 

This study presents kinetic data obtained with a microreactor set-up both at atmospheric pressure and at high pressures up to 50 bar as a function of temperature and of the partial pressures from which power-law expressions and apparent activation energies are derived. An additional microreactor set-up equipped with a calibrated mass spectrometer was used for the isotopic exchange reaction (DER) N2 + N2 = 2 N2 and the transient kinetic experiments. The transient experiments comprised the temperature-programmed desorption (TPD) of N2 and H2. Furthermore, the interaction of N2 with Ru surfaces was monitored by means of temperature-programmed adsorption (TPA) using a dilute mixture of N2 in He. The kinetic data set is intended to serve as basis for a detailed microkinetic analysis of NH3 synthesis kinetics [10] following the concepts by Dumesic et al. [11]. 

For this purpose we studied a temperature-programmed interaction of CH with a-oxygen. Experiments were carried out in a static setup with FeZSM-5 zeolite catalyst containing 0.80 wt % Fe203. The setup was equipped with an on-line mass-spectrometer and a microreactor which can be easily isolated from the rest part of the reaction volume. The sample pretreatment procedure was as follows. After heating in dioxygen at 823 K FeZSM-5 cooled down to 523 K. At this temperature, N2O decomposition was performed at 108 Pa to provide the a-oxygen deposition on the surface. After evacuation, the reactor was cooled down to the room temperature, and CH4 was fed into the reaction volume at 108 Pa. 

Activities of the catalysts were measured on a microreactor. About 3 g of catalyst was charged into a reactor and heat-treated in nitrogen at reaction temperature. Acetic acid was added to the process and the reaction was initiated by switching nitrogen to ethylene. Reaction product analyses were performed by an online gas chromatograph equipped with a flame ionization detector (Perkin Elmer Auto System II). 

Overall, the microreactor provides greater safety for individuals and equipment and reduces the likelihood of loss of process and the consequent disruption and even loss of sales that can follow. In common with other fine chemical manufacturers, most pharmaceutical companies have programs to capture the benefits of flow microreactors as adjuncts to or even replacements for their current batch methods for scaling up production of candidate molecules to satisfy clinical and manufacturing needs. This paper attempts to demonstrate that microreactors can be deployed more widely in pharmaceutical R D than as a tool for enhanced production and that they have the potential to underpin significant paradigm shifts in both early- and late-phase R D. 

Ruy et al. have performed a similar reaction under microreactor conditions in a multiphase solvent system containing an ionic liquid as the catalyst carrier and reaction promoter [35]. Their system consisted of two T-shaped micromixers (i.d. 1,000 and 400 pm) and a capillary stainless steel tube as an RTU (1,000 pm i.d. and 18 m length, giving a 14.1 ml volume), equipped with pumps and control valves. Under the optimized conditions, Pd-catalysed carbonylation of aromatic iodides in the presence of a secondary amine provided only the double carbonylated product, ot-ketoamide, while the amide obtained by the single carbonylation was observed in high quantities only when the reaction was performed in batch (Scheme 13). 

In this study, a nonchemical means of encoding the identity of each compound was used. The original polymer-bound reagent was placed in a porous microreactor equipped with a radio-frequency device that can be used for identification.168 The porous micro-... 

The catalytic activity for dehydration of iso-propanol on PSM and AMM samples was studied in a quartz microreactor. 0.2 g catalyst was used for each run. Isopropanol was introduced to the reactor by a helium flow (20 ml/min) which was saturated with iso-propanol vapor at room temperature. The reaction product was analyzed by HP6890 GC equipped with a FID detector. 

The catalysts were tested in the dehydrogenation of tetrahydrothiophene (DHN of THT), the hydrodesulphurization of thiophene (HDS of thiophene) and the hydrogenation of biphenyl (HN of BP). The reactions were carried out in the vapor phase using dynamic flow microreactors equipped with an automatic online analysis. Reaction conditions are given in Table 1. 

The reaction system consisted of a flow stainless steel microreactor operated at 5 MPa and 523-623 K. Hydrogen and carbon monoxide were supplied to the reactor through mass flow controllers (Brooks). Products were sampled through heated lines into an on-line gas chromatograph equipped with TCD and FID detectors, with a Porapak Q + R column for Ci products and a Tenax column for hydrocarbons (C,-C13) or alcohols (Cj-Cfi), respectively. Reaction products were identified with a gas chromatograph-mass spectrometer (Hewlett-Packard Model 5971), using a 60 m DB-1 capillary column (J W Scientific). 

The directed sorting approach (or mix-and-sort approach) uses small synthetic objects, usually called microreactors, which are equipped with a readable encoding system. Typically the synthetic objects can be resin... 

Fig. 4.10 Chip-type microreactor equipped with flow and temperature sensors from the Massachusetts Institute of Technology [6],...

Catalysts pre-treatment (calcination and reduction) was performed in the same testing system or in a parallel automatic activation system prior to reaction test Calcination is carried out at 600 °C under airflow for 8 h and reduction at 250 °C for 2 h under hydrogen flow. Catalytic tests were carried out at 30 bar total pressure, temperature range 200-240°C, and 2.26h-1 WHSV, H2/hydrocarbons molar ratio of 2.93. Each fixed bed microreactor contained 500 mg of catalyst (particle size 0.4—0.6 mm, for which there are no internal diffusion limitations). Reaction products distribution are analysed using a gas chromatograph (Varian 3380GC) equipped with a Plot Alumina capillary column. 

Researchers at BASF have shown that microreactors can be utilized that give access to operating conditions that cannot be realized by means of macroscopic equipment. They succeeded in improving yield and selectivity in a highly exothermal two-phase reaction in connection with the synthesis of a vitamin precursor. At Degussa company, a microreactor test facility for proprietary reactions is under construction. The major focus in this context is the implementation of microreaction devices as powerful tools for process development and, in particular, for the evaluation of new reaction pathways. 

In general, microreactors are systems consisting of tiny channels in which a number of fluidizable substances are combined under specific physical conditions. The temperature, pressure and dwell time are the most important parameters, which are either set or altered by peripheral equipment such as pumps, heaters/coolers and control systems. 

The combination of fluoride ions and enol silyl ethers provides a useful method for the generation of enolate anions [9]. Watts, Haswell and coworkers applied a borosilicate glass microreactor, having channel dimensions of 100 pm x 50 pm and equipped with an electrosmotic flow (EOF) pumping system, to the C-acylation of enolate anions, which leads to 1,3-diketones [10,11]. A THF solution of tetrabutyl-ammonium fluoride (TBAF) was placed in reservoir A, a THF solution of benzoyl... 

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