Flowing method

Nelsen F M and Eggertsen F T 1958 Determination of surfaoe area adsorption measurements by a oontinuous flow method Anal. Chem. 30 1387-90... 

Chance B 1951 Rapid and sensitive spectrophotometry. I. The accelerated and stopped-flow methods for the measurement of the reaction kinetics and spectra of unstable compounds in the visible region of the spectrum Rev. Sci. Instrum 22 619-27... 

Whitney, W.J., Comparative Study of Mixed and Isolated Flow Methods for Cooled Turbine Performance Analysis, NASA, TM X-1572, 1968. 

The resistance to flow method (K[ ), which has been employed by industry for years, has now been adopted by the ASME Code for rupture disc. Sizing is performed on a relief system basis and not by capacity of individual components. The key elements of tills metliod are ... 

Continuous flow devices have undergone careful development, and mixing chambers are very efficient. Mixing is essentially complete in about 1 ms, and half-lives as short as 1 ms may be measured. An interesting advantage of the continuous flow method, less important now than earlier, is that the analytical method need not have a fast response, since the concentrations are at steady state. Of course, the slower the detection method, the greater the volumes of reactant solutions that will be consumed. In 1923 several liters of solution were required, but now reactions can be studied with 10-100 mL. 

The anomalous behavior of quinazoline was first discovered by Albert et who made the surprising observation that 4-methyl-quinazoline 2.5) was a weaker base than quinazoline (pA 3.5). Mason then observed that the ultraviolet spectrum of the quinazoline cation was abnormal but that the spectrum of 4-methylquin-azoline was normal (see Fig. 2). These anomalies led to the suggestion that water adds covalently to the cation of quinazoline to give 12 (R = H). The occurrence and position of hydration were confirmed by a detailed study of the ultraviolet and infrared spectra of the anhydrous and hydrated hydrochlorides and by mild oxidation of the cation to 4(3 )-quinazolinone. Using the rapid-reaction technique (the continuous-flow method), the spectrum of the unstable... 

Most substituents (Q, Me, OMe) in the 2-position have only a small effect, if any, on the hydration of the quinazoline cation they are similar in this respect to substituents in the 5-, 6-, and 8-positions (see above). Although hydration in the 2-aminoquinazoline cation was at first considered absent,a closer examination of the entire spectra of both species indicated that the cation spectrum may be that of a mixture. Hydration in the cation has now been confirmed by the rapid-reaction technique (the stopped-flow method) which showed that the unstable hydrated neutral species had a half-life of 4.0 sec at 20° and pH 9.60. The 2-hydroxyquinazoline cation has not been studied, but... 

Because flashing steam-condensate lines represent two-phase flow, with the quantity of liquid phase depending on die system conditions, these can be designed following the previously described two-phase flow methods. An alternate by Ruskin [28] uses the concept but assumes a single homogeneous phase of fine liquid droplets dispersed in the flashed vapor. Pressure drop was calculated by the Darcy equation ... 

Grolmes, M. A., Leung, J. C. and Fauske, H. K, A Review of Simplified Multiphase Flow Methods for Emergency Relief Calculations, Paper Presented at the AIChE 1990 Spring National Meeting, Orlando, FL, March 18-22, 1990. 

Leung, J. C. and Nazario, F. N., Two-Phase Flashing Flow Methods and Comparisons, Journal Loss Prevention Process Industries, (3), 253-260, April 1990. 

Optimal flow method, 261 Optimization non-constrained, 286 of functionals, 305 Ordinary value, 338 Orthogonalization, Schmidt," 65 Osaki, S., 664 Oscillation hysteresis, 342 Oscillations autoperiodic, 372 discontinuous theory, 385 heteroperiodic, 372 piecewise linear, 390 relaxation asymptotic theory, 388 relaxation, 383 Oscillatory circuit, 380 "Out field, 648 existence of, 723... 

The stopped-flow and quenched-flow methods for fast reactions involve the fast flowing together of separate solutions of the reactants. This rapid mixing can be coupled to a rapid-response method for monitoring the progress of the reaction. With such methods one can determine rate constants up to about 5 X 102 s 1 (i.e., t n > 1 ms). The instrumentation for stopped-flow kinetics is readily available commercially. With special adaptations, one can gain another one or two orders of magnitude. 

The stopped-flow method generates ordinary kinetic data, presenting values of the property Y, as a function of time. At one time, values were read from a Polaroid photograph of the oscilloscope, but nowadays computer acquisition, presentation, and... 

Revisions of the continuous-flow method have been made to allow observations along the length of the flow tube rather than at right angles.5 This method, fast continuous flow, eliminates the dead time during which the reaction cannot be observed. Kinetic data can be extracted to a time resolution of nearly 10 p,s, but the mathematics is more complicated in this limit, because the mixing and chemical reaction occur on the same time scale. Rate constants nearly as large as the diffusion-controlled value have been determined in favorable cases.6... 

NMR spectroscopy finds a number of applications in chemical kinetics. One of these is its application as an analytical tool for slow reactions. In this method the integrated area of a reactant, intermediate, or product is determined intermittently as the reaction progresses. Such determinations are straightforward and will not concern us further, except to note that the use of an internal standard improves the accuracy. With flow mixing, one may examine even more rapid reactions. This is simply overflow application of the stopped-flow method. 

Competition reactions ad eosdem, 106 ad eundem, 105 (See also Reactions, trapping) Competitive inhibitor, 92 Complexation equilibria, 145-148 Composite rate constants, 161-164 Concentration-jump method, 52-55 Concurrent reactions, 58-64 Consecutive reactions, 70, 130 Continuous-flow method, 254—255 Control factor, 85 Crossover experiment, 112... 

Proton inventory technique. 21.9-220 Pseudo-first-order kinetics, 16 Pulse-accelerated-flow method. 255 Pulse radiolysis, 266-268 Pump-probe technique. 266... 

Spin trap, 102 Statistical kinetics, 76 Steady-state approximation, 77-82 Stiff differential equations, 114 Stoichiometric equations, 12 Stopped-flow method, 253-255 Substrate titration, 140 Success fraction approach, 79 Swain-Scott equation, 230-231... 

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