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Reaction continuous flow

Dimensional Analysis. Dimensional analysis can be helpful in analyzing reactor performance and developing scale-up criteria. Seven dimensionless groups used in generalized rate equations for continuous flow reaction systems are Hsted in Table 4. Other dimensionless groups apply in specific situations (58—61). Compromising assumptions are often necessary, and their vaHdation must be estabHshed experimentally or by analogy to previously studied systems. [Pg.517]

Catalytic activity for the selective oxidation of H2S was tested by a continuous flow reaction in a fixed-bed quartz tube reactor with 0.5 inch inside diameter. Gaseous H2S, O2, H2, CO, CO2 and N2 were used without further purification. Water vapor (H2O) was introduced by passing N2 through a saturator. Reaction test was conducted at a pressure of 101 kPa and in the temperature range of 150 to 300 °C on a 0.6 gram catalyst sample. Gas flow rates were controlled by a mass flow controller (Brooks, 5850 TR) and the gas compositions were analyzed by an on-line gas chromotograph equipped with a chromosil 310 coliunn and a thermal conductivity detector. [Pg.426]

Figure 6.30. Schematic diagram of a reactor used continuously for up to 500 h for fluorous biphasic reactions without gaseous reagents. [81] (A. Yoshidaetal, Development of the continuous-flow reaction system based on the Lewis acid-catalysed reactions in a fluorous biphasic system, Green Chemisty, 5, (2003), 555) Reproduced by permission of The Royal Society of Chemistry. Figure 6.30. Schematic diagram of a reactor used continuously for up to 500 h for fluorous biphasic reactions without gaseous reagents. [81] (A. Yoshidaetal, Development of the continuous-flow reaction system based on the Lewis acid-catalysed reactions in a fluorous biphasic system, Green Chemisty, 5, (2003), 555) Reproduced by permission of The Royal Society of Chemistry.
Figure 8.5. Schematic view of continuous flow reaction setup for IL/scCC>2 systems (adapted from reference [81]). C compressor, CT cold trap, D dosimeter, DP depressuriser, F flowmeter, M mixer, MF metal filter, P HPLC pump, PT pressure transducer and thermocouple, R reactor, S styrene... Figure 8.5. Schematic view of continuous flow reaction setup for IL/scCC>2 systems (adapted from reference [81]). C compressor, CT cold trap, D dosimeter, DP depressuriser, F flowmeter, M mixer, MF metal filter, P HPLC pump, PT pressure transducer and thermocouple, R reactor, S styrene...
Comparison between the periodic-pulse and continuous-flow reactions for propene oxidation... [Pg.158]

Scheme 13) (35). This high selectivity can be obtained with the 1 2 amino alcohol-borane reagent, however, the 1 1 reagent is less reactive and affords only low stereoselectivity (36). The continuous-flow reaction using a polymer-bound amino alcohol provides evidence for the catalytic nature of the reduction with respect to the chiral ancillary. The reduction is accelerated by the presence of the amino alcohol-borane adduct, and the product is not bound to the complex. [Pg.76]

The ultrasonic irradiation of aqueous solution of PNP was carried out with a Branson 200 sonifier that was operated at 20 KHz and with an output of electrical power of 84 W. Reactions were performed in a stainless-steel, continuous-flow reaction cell operated in the batch mode. All reactions were carried out with air-saturated solutions, and the concentration of p-benzo-quinone (p-BQ) was determined spectrophotometrically. Hydrogen peroxide... [Pg.455]

Table 4 Suzuki-Miyaura reaction used as a model to demonstrate the optimization of microwave induced continuous flow reactions... Table 4 Suzuki-Miyaura reaction used as a model to demonstrate the optimization of microwave induced continuous flow reactions...
Scheme 45 Microwave-heated continuous flow reactions... Scheme 45 Microwave-heated continuous flow reactions...
Thus the rate equation for continuous-flow-reactions is... [Pg.282]

Figure 7.21 Bench scale continuous flow reaction system for fluorous-organic biphasic chemistry. [Reprinted with permission from QSAR Comb. Set, 2006, 25, 697-702. Copyright 2006 Wiley-VCH.]... Figure 7.21 Bench scale continuous flow reaction system for fluorous-organic biphasic chemistry. [Reprinted with permission from QSAR Comb. Set, 2006, 25, 697-702. Copyright 2006 Wiley-VCH.]...
The Damkohler is a dimensionless number that can give us a quick estimate of the degree of conversion that can be achieved in continuous-flow reactions. The Damkdhler number is the ratio of the rate of reaction of A to the rate of convective transport of A at the entrance to the reactor. For first- and second-order ineversible reactions the Damkohler numbers are... [Pg.86]

The catalytic cracking of n-hexane was earned out in a continuous flow reaction system over 0.5 g of electrically heated Ni/Al203 catalyst at 733K and 1 atm. The total flow rate of hexane and nitrogen was controlled at 60 ml per minute. I he amount of carbon deposited on the used catalysts was determined by chemical analysis. The eilluent gas was analyzed by gas chromatography (HP 5890 A) using a flame ionization detector. [Pg.254]

Stopped or continuous flow reaction methods can be utilized with synchrotron-based SAXS measurements to determine reaction kinetics, including protein folding, nanoparticle growth, breakdown, and aggregation. Using a synchrotron X-ray source, the SAXS spectrum can be collected with a one or two dimensional detector with good quality in periods as short as 0.001 s. [Pg.153]

In Table XVIII there are listed conditions for various transformations of alkylaromatics over crystalline aluminosilicate catalysts, many of which occurred under alkylation conditions. Toluene disproportionation, mainly to benzenes and xylenes over REX (43), occurred in low yield at 264° and 400 psig in the liquid phase severe aging occurred in this reaction, even under hydrogen pressure. o-Xylene isomerized to mixtures of m- and p-xylenes in liquid phase continuous flow reactions over H-mordenite at 200-600° (134) and over REX at 177-204° (43). [Pg.329]

Plastic microcapillary flow disk (MFD) reactors have been constructed from a flexible, plastic microcapillary film (MCF), comprising parallel capillary channels with diameters in the range of 80-250 jxm. MCFs are wound into spirals and heat treated to form solid disks. These reactors are capable of carrying out continuous flow reactions at elevated temperatures and pressures with a controlled residence time. ... [Pg.113]

A scale-up preparation of ionic liquids is illustrative. Here the reaction of 1-methylimidazole with n-butyl bromide under solvent-free conditions is highly exothermic and prone to runaway in a batch reaction of any significant scale. However, using a flow reactor with reaction tubes between 2 mm and 6 mm diameter, fed by a micromixer with 0.45 mm channels, a continuous flow reaction at 85 °C was able to produce over... [Pg.104]

Other reactions evaluated by the authors included Wittig-Horner olefination and a series of ring-closing metathesis (RCM) reactions, employing Grubb s II catalyst. In all cases, a reduction in power consumption, increase in yield, and reduction in reaction time were obtained as a result of employing microwave-assisted continuous flow reactions [33],... [Pg.171]

Coupled with the fact that the proportion of trace metal contaminants detected within continuous flow reaction products is inherently low, due to reduced catalyst degradation, the use of a scavenger cartridge at the end of a reaction sequence represents a relatively long-term solution to this problem. Other examples of the use of solid-supported scavengers have been reported by Ley and co-workers [65], where in one example, two scavenger modules, comprising QuadraPure TU (126) and phosphane resin, were used in the synthesis of 1,4-disubstituted-l,2,3-triazoles [66], and by Watts and co-workers [67], where silica-supported copper sulfate was used for the removal of residual dithiol (ppb) in the synthesis of 1,3-dithiolanes and 1,3-dithianes. [Pg.190]

A novel method, a periodic pulse technique in which a catalyst is exposed to forced redox cycles, was applied to the oxidation of C2II4 on Pt/Al Os catalysts. It was found that the catalysis are sintered at relatively low temperature, i.e., at 588 K, in reaction atmosphere, and that the periodic pulse technique actually accelerates the sintering. The sintering in the continuous flow reaction for ca. 1000 h could be reproduced within ca, 100 h, indicating the possibility of rapid estimation of catalyst life. It is suggested that the sintering in reaction atmosphere is governed by the chemical factors rather than the thermal ones. [Pg.553]

The continuous flow reaction was carried out with a fixed bed tubular metal reactor (18 mm (i.d.) X 100 cm) at atmospheric pressure. The catalyst was packed and heated with shell furnace. Air and ethanol (rectified spirit containing 88% ethanol) were introduced from the top of the reactor at desired rates (considering lower explosive limit). The reaction being exothermic, was started at 50-60° lower than the desired temperature. Acetic acid was condensed and collected from the bottom of the reactor. The vent gas contained air, carbondioxide, moisture, acetaldehyde and uncondensed acetic acid. [Pg.480]

Presently, pharmaceuticals are produced batchwise in multipurpose plants. For different reasons increasingly dedicated mono-production plants [25] are recommended. The integration of microreaction concepts into existing production plants is still ongoing. Continuous flow reactions are less flexible than batch reactions, particularly during workup steps such as phase separations, crystallizations and other operations. [Pg.466]


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