Pyrex microreactor

Determination of Metal Precursor Mobilities During Pretreatment. Relative precursor mobilities were obtained by premixing the sllica-or alumina-supported metal catalysts with pure silica (Cab-O-Sll, grade M-5, Cabot Corp.) or pure alumina (Alon C, Cabot Corp.) In a 1 2 ratio prior to pretreatment. The catalyst and silica were ground together using a mortar and pestle for at least 0.5 hr. before they were placed in the Pyrex microreactor for pretreatment. 

A series of Chromia-Alumina aerogel catalysts containing different contents of chromium was prepared by autoclave method. The specific areas of the catalysis were measured with Ng at 77°K according to the BET method. Their structural properties were determined from the X ray diffraction patterns recorded on a philips diffractometer PW 1050/70. EPR measurements were performed with a 8ruker ZOO TT spectrometer at 77°K operating in X band. DPPH was used as the g value standard. Kinetic data were obtained in dynamic pyrex microreactor operating at atmospheric pressure as described elsewhere (ref. 3). 

Mukae et al. (2007) also compared a Pyrex batch reaction vessel (8 mm) with several Pyrex microreactors [channel dimensions = 100 pm (wide) x 40 pm (deep) 1.20 cm (long)] for the photocycloaddition of... 

In 1997, Harrison and coworkers reported on the synthesis of an azobenzene compound in microfluidic channels [37] for the purpose of combinatorial synthesis. The azo coupling of N,N-dimethylaniline and 4-nitrobenzene diazonium tetrafluor-oborate (Scheme 4.17) was carried out in a Pyrex microreactor driven by electro-osmotic flow. A few years later, Hisamoto et al. described a phase transfer diazo coupling reaction carried out in a microfluidic chip [38]. By providing a huge liquid-liquid interface between a solution of 5-methylresorcinol dissolved in ethyl acetate and an aqueous solution of 4-nitrobenzenediazonium tetrafluoroborate (Scheme 4.18), 100% conversion within a 2.3 s residence time was achieved. In contrast to macroscale experiments, the reaction could be accelerated and the formation of unwanted precipitates and bisazo side products was successfully suppressed. 

Apparatus and Procedure. The kinetic studies of the catalysts were carried out by means of the transient response method (7) and the apparatus and the procedure were the same as had been used previously (8). A flow system was employed in all the experiments and the total flow rate of the gas stream was always kept constant at 160 ml STP/min. In applying the transient response method, the concentration of a component in the inlet gas stream was changed stepwise by using helium as a balancing gas. A Pyrex glass tube microreactor having 5 mm i.d. was used in a differential mode, i.e. in no case the conversion of N2O exceeded 7 X. The reactor was immersed in a fluidized bed of sand and the reaction temperature was controlled within + 1°C. 

Method //was designed for a bonded microreactor. After the channel was sealed with a Pyrex top plate using the anodic bonding technique, the liquid precursor was infiltrated into the microreactor through the outlet of the reactor under slight pressure and withdrawn. A thin film of solution remained on the walls of the microchannel. 

The capillary plasma reactor consists of a Pyrex glass body and mounted electrodes which are not in direct contact with the gas flow in order to eliminate the influence of the cathode and anode region on CO2 decomposition. Analysis of downscaling effects on the plasma chemistry and discharge characteristics showed that the carbon dioxide conversion rate is mainly determined by electron impact dissociation and gas-phase reverse reactions in the capillary microreactor. The extremely high CO2 conversion rate was attributed to an increased current density rather than to surface reactions or an increased electric field. 

Catalytic activity data for both CO and propane oxidation were obtained using a conventional continuous flow microreactor. The catalyst sample (0.5g) is situated in a pyrex glass tube located within a stainless steel heated block. Catalyst samples were activated by in situ preheating in the reactor for 2 hours under a flow of air. The catalysts were then allowed to cool to ambient temperature still under the air flow before acquiring %conversion versus temperature data. Input gas mixture compositions, which were controlled by mass flow controllers, and flow rates are shown in Table 10. 

Biochemical analysis on nanoliter scale is precisely carried out by micrototal analysis system (pTAS) which consists of microreactors, microfluidic systems, and detectors. Performance of the pTAS depends on micromachined and electrochemically actuated micropump capable of precise dosing of nanoliter amounts of liquids such as reagents, indicators, or calibration fluids [28]. The dosing system is based on the displacement of the liquid from a reservoir which is actuated by gas bubbles produced electrochemically. Electrochemical pump and dosing system consist of a channel structure micro-machined in silicon closed by Pyrex covered with novel metal electrodes. By applying pulsed current to the electrodes, gas bubbles are produced by electrolysis of water. The liquid stored in the meander is driven out into the microchannel structure due to expansion of gas bubbles in the reservoir as shown in Fig. 11.8. 

Nitrite photolysis (Barton reaction) Pyrex glass-covered stainless-steel microreactor 15 W black light lamp (352 nm) [7]... 

Maeda et al. examined intramolecular [2 + 2] photocycloadditions of 1-cyano-naphthalene derivatives (I) in microchannel reactors [4]. They use microreactors made of polydimethylsiloxane (PDMS) and Pyrex glass. With a photolithographic method, channels of 300 pm width, 50 pm depth and 45-202 mm length are fabricated. For the photoreaction (Scheme 16.2), flow rates of 0.03-0.005 mLh are applied and a xenon lamp with a UV-29 Alter (> 290 nm) is used as a light source. The authors report that under the conditions prevailing in the microreactor, higher regioselectivity and efficiency are achieved compared with batch process conditions. 

An efficient oxidation of glucose to gluconic add in phosphate buffer solution can be performed using a porous gold(O) catalyst in a Pyrex capillary tubing microreactor (Figure 7.18) [98]. The yield increases with increase in reaction time. A pH range of... 

Figure 25.3 Single-channel microreactor covered with Pyrex glass (heating element not visible) filled with 0.1 wt.% rhodium on alumina [8].

Figure 10.12 shows the fabrication steps of a chip-like microreactor made from a silicon wafer as described by Pattekar and Kothare [532]. Firstly, a 10-p.m thick photoresist layer was coated onto the silicon chip, which served as the etch mask for Deep Reactive Ion Etching (DRIE). Then the photoresist was removed and Pyrex glass was connected to the chip by anodic bonding to seal the channels. Teflon capillaries were then bonded as inlet/outlet connectors to the chip. On the reverse side of the chip, the photoresist was patterned, which served as an etch mask for a... 

Therefore, a silicon-Pyrex multichatmel microreactor was developed that allows both ozone oxidation and the following reductive treatment in one reactor module. Figure 6.31 shows the microstructured reactor schematically. The small posts... 

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