In a continuous flow

Reaction times can be as short as 10 minutes in a continuous flow reactor (1). In a typical batch cycle, the slurry is heated to the reaction temperature and held for up to 24 hours, although hold times can be less than an hour for many processes. After reaction is complete, the material is cooled, either by batch cooling or by pumping the product slurry through a double-pipe heat exchanger. Once the temperature is reduced below approximately 100°C, the slurry can be released through a pressure letdown system to ambient pressure. The product is then recovered by filtration (qv). A series of wash steps may be required to remove any salts that are formed as by-products. The clean filter cake is then dried in a tray or tunnel dryer or reslurried with water and spray dried. 

Continuous-Flow Stirred-Tank Reactor. In a continuous-flow stirred-tank reactor (CSTR), reactants and products are continuously added and withdrawn. In practice, mechanical or hydrauHc agitation is required to achieve uniform composition and temperature, a choice strongly influenced by process considerations, ie, multiple specialty product requirements and mechanical seal pressure limitations. The CSTR is the idealized opposite of the weU-stirred batch and tubular plug-flow reactors. Analysis of selected combinations of these reactor types can be useful in quantitatively evaluating more complex gas-, Hquid-, and soHd-flow behaviors. 

Nonicosahedral carboranes can be prepared from the icosahedral species by similar degradation procedures or by reactions between boranes such as B H q and B H with acetylenes. The degradative reactions for intermediate C2B H 2 species (n = 6-9) have been described in detail (119). The small closo-Qr Yi 2 species (n = 3-5 are obtained by the direct thermal reaction (500—600°C) of B H using acetylene in a continuous-flow system. The combined yields approach 70% and the product distribution is around 5 5 1 of 2,4-C2B3H2 [20693-69-0] to l,6-C2B Hg [20693-67-8] to 1,5-C2B3H3 [20693-66-7] (120). A similar reaction (eq. 60) employing base catalysts, such as 2 6-dimethylpyridine at ambient temperature gives nido-2 >-(Z, ... 

Production of potassium permanganate in the CIS is beheved to be from potassium manganate. Electrolysis of potassium manganate in a continuous-flow electrolytic cell with turbulent electrolyte flow and continuous crystallization has been reported (72). 

Better results were obtained when a mixture of chloroform and either pyrazole or C-methylpyrazoles was heated at 555 °C in a continuous-flow vapour phase reactor (79JCS(P1)2786). 2-Chloropyrimidines were obtained in high yields (51-89%). Indazole similarly gave only 2-chloroquinazoline (68%). 

Fig. 6. Breakthrough curves for aqueous acetone (10 mg 1" in feed) flowing through exnutshell granular active carbon, GAC, and PAN-based active carbon fibers, ACF, in a continuous flow reactor (see Fig. 5) at 10 ml min" and 293 K [64]. C/Cq is the outlet concentration relative to the feed concentration. Reprinted from Ind. Eng. Chem. Res., Volume 34, Lin, S. H. and Hsu, F. M., Liquid phase adsorption of organic compounds by granular activated carbon and activated carbon fibers, pp. 2110-2116, Copyright 1995, with permission from the American Chemical Society.

Harada, M., Arima, K., Eguchi, W. and Nagata, S., 1962. Micromixing in a continuous flow reactor. Memoir of the Faculty of Engineering, Kyoto University, Japan, 24, 431. 

A similar catalytic dimerization system has been investigated [40] in a continuous flow loop reactor in order to study the stability of the ionic liquid solution. The catalyst used is the organometallic nickel(II) complex (Hcod)Ni(hfacac) (Hcod = cyclooct-4-ene-l-yl and hfacac = l,l,l,5,5,5-hexafluoro-2,4-pentanedionato-0,0 ), and the ionic liquid is an acidic chloroaluminate based on the acidic mixture of 1-butyl-4-methylpyridinium chloride and aluminium chloride. No alkylaluminium is added, but an organic Lewis base is added to buffer the acidity of the medium. The ionic catalyst solution is introduced into the reactor loop at the beginning of the reaction and the loop is filled with the reactants (total volume 160 mL). The feed enters continuously into the loop and the products are continuously separated in a settler. The overall activity is 18,000 (TON). The selectivity to dimers is in the 98 % range and the selectivity to linear octenes is 52 %. 

The use of acidic chloroaluminates as alternative liquid acid catalysts for the allcy-lation of light olefins with isobutane, for the production of high octane number gasoline blending components, is also a challenge. This reaction has been performed in a continuous flow pilot plant operation at IFP [44] in a reactor vessel similar to that used for dimerization. The feed, a mixture of olefin and isobutane, is pumped continuously into the well stirred reactor containing the ionic liquid catalyst. In the case of ethene, which is less reactive than butene, [pyridinium]Cl/AlCl3 (1 2 molar ratio) ionic liquid proved to be the best candidate (Table 5.3-4). 

The Pt film, with a surface area corresponding to NG=4.2-10 9 mol Pt, measured via surface titration of oxygen with C2H4,1,4 is exposed to po2 — 4.6 kPa, PC2H4 = 0.36 kPa at 370°C in a continuous flow gradientless (CSTR) reactor of volume 30 cm3. The rate of C02 formation is monitored via an infrared analyzer.1,4... 

An Experimental Study Using Feed Perturbations for a Free-Radically Initiated Homogeneous Polymerization in a Continuous-Flow Stirred-Tank Reactor... 

Probably the first non-covalent immobilization of a chiral complex with diazaligands was the adsorption of a rhodium-diphenylethylenediamine complex on different supports [71]. These solids were used for the hydride-transfer reduction of prochiral ketones (Scheme 2) in a continuous flow reactor. The inorganic support plays a crucial role. The chiral complex was easily... 

Although catalytic wet oxidation of acetic acid, phenol, and p-coumaric acid has been reported for Co-Bi composites and CoOx-based mixed metal oxides [3-5], we could find no studies of the wet oxidation of CHCs over supported CoO catalysts. Therefore, this study was conducted to see if such catalysts are available for wet oxidation of trichloroethylene (TCE) as a model CHC in a continuous flow fixal-bed reactor that requires no subsequent separation process. The supported CoOx catalysts were characterized to explain unsteady-state behavior in activity for a certain hour on stream. 

Girguis PR, AE Cozen, EF Delong (2005) Growth and population dynamics of anaerobic methane-oxidizing archaea and sulfate-reducing bacteria in a continuous-flow reactor. Appl Environ Microbiol 71 3725-3733. 

The cracking of diphenylmethane (DPM) was carried out in a continuous-flow tubular reactor. The liquid feed contained 29.5 wt.% of DPM (Fluka, >99%), 70% of n-dodecane (Aldrich, >99% solvent) and 0.5% of benzothiophene (Aldrich, 95% source of H2S, to keep the catalyst sulfided during the reaction). The temperature was 673 K and the total pressure 50 bar. The liquid feed flow rate was 16.5 ml.h and the H2 flow rate 24 l.h (STP). The catalytic bed consisted of 1.0 g of catalyst diluted with enough carborundum (Prolabo, 0.34 mm) to reach a final volume of 4 cm. The effluent of the reactor was condensed at high pressure. Liquid samples were taken at regular intervals and analyzed by gas chromatography, using an Intersmat IGC 120 FL, equipped with a flame ionization detector and a capillary column (Alltech CP-Sil-SCB). 

While alkane metathesis is noteworthy, it affords lower homologues and especially methane, which cannot be used easily as a building block for basic chemicals. The reverse reaction, however, which would incorporate methane, would be much more valuable. Nonetheless, the free energy of this reaction is positive, and it is 8.2 kj/mol at 150 °C, which corresponds to an equihbrium conversion of 13%. On the other hand, thermodynamic calculation predicts that the conversion can be increased to 98% for a methane/propane ratio of 1250. The temperature and the contact time are also important parameters (kinetic), and optimal experimental conditions for a reaction carried in a continuous flow tubiflar reactor are as follows 300 mg of [(= SiO)2Ta - H], 1250/1 methane/propane mixture. Flow =1.5 mL/min, P = 50 bars and T = 250 °C [105]. After 1000 min, the steady state is reached, and 1.88 moles of ethane are produced per mole of propane consmned, which corresponds to a selectivity of 96% selectivity in the cross-metathesis reaction (Fig. 4). The overall reaction provides a route to the direct transformation of methane into more valuable hydrocarbon materials. 

The figure indicates the transport of gas bubbles through the reaction channel. In contrast to the standard process, which is of batch type, the micro reactor allows the fluids to be proceeded in a continuous-flow manner. 

There is an additional point to be made about this type of processing. Many gas-phase processes are carried out in a continuous-flow manner on the macro scale, as industrial or laboratory-scale processes. Hence already the conventional processes resemble the flow sheets of micro-reactor processing, i.e. there is similarity between macro and micro processing. This is a fimdamental difference from most liquid-phase reactions that are performed typically batch-wise, e.g. using stirred glass vessels in the laboratory or stirred steel tanks in industrial pilot or production plants. 

Regardless of the location of the protein and its state, cell separation needs to be inemensive, simple, and reliable, as large amounts of fermentation-broth dilute in the desired product may be handled. The objectives are to obtain a well-clarified supernatant and solids of maximum dryness, avoiding contamination by using a contained operation. Centrifugation or crossflow filtration is t ically used for cell separation, and both unit operations can be run in a continuous-flow mode [Datar and Rosen, in Stephanopoulos (ed.), op. cit., pp. 369-503]. In recent years, e3q>anded-bea adsorption has become an alternative. It combines broth clarification and adsorption separation in a single step. 

Stripping analysis with inherent pre-concentration seems attractive to CFA, but until recently such a procedure appeared rather exceptional. It has been used in the automatic determination of heavy metals in water by anodic stripping voltammetry (ASV12S) in a continuous flow cell with a mercury-covered graphite electrode, having the advantage that one can distinguish... 

Chakrabarti, T. and Subrahmanyam, P.V.R., Biological hydrolysis of urea in a continuous flow stirred tank reactor under laboratory conditions—a bench scale study, Proc. 36th Industrial Waste Conference, Purdue University, pp. 477, 1981. 

Semibatch or semiflow processes are among the most difficult to analyze from the viewpoint of reactor design because one must deal with an open system under nonsteady-state conditions. Hence the differential equations governing energy and mass conservation are more complex than they would be for the same reaction carried out batchwise or in a continuous flow reactor operating at steady state. 

The supported aqueous phase methodology was applied to the system Pd(OAc)2/5 TPPTS, a catalytic precursor for the Trost-Tsuji reaction. The characterization of the solid by 31P MAS NMR confirms the presence of Pd°(TPPTS)3 as the main surface species. The catalytic properties of the solid were tested for the allylic substitution of E-cinnamylethylcarbonate by different nucleophiles such as ethyl acetoacetate, dimethyl malonate, morpholine, phenol, and 2-mercapto-pyridine. The absence of palladium leaching was demonstrated, and having solved the problem of water leaching from the solid to the organic phase, the SAP-Pd catalyst was successfully recycled several times without loss in its activity. It was used in a continuous flow experiment which... 

A Pt/Z12 sample with ZSM-12 structure having a SiCVA Os ratio of 100 and containing ca. 200 ppm Pt was prepared following the impregnation procedures reported earlier [6], Transalkylation reaction tests were conducted in a continuous flow... 

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