Concentric consecutive

Interdigital Concentric Consecutive Mixing Most Relevant Citations... 

This interdigital concentric consecutive microstructured mixer is composed of a housing with a cylindrical recess in which a platelet stack is inserted (see Figure 1.108) [130], The device can be operated up to 100 bar and at a temperature of600 °C. 

Figure 1.108 Interdigital concentric consecutive microstructured mixers have the potential for use as chemical production tools, as evidenced by their comparatively large outer dimensions and owing to an internal numbering-up of the micro-structured platelets. Left, front StarLam300 right, back StarLam3000 [130],...

Mixer type Interdigital concentric consecutive micro mixer StarLam300 Number of platelets required for forming a stack 2... 

Figure 1.111 Flow rate dependence of the Dushman mixing quality of the interdigital concentric consecutive microstructured mixers of the StarLam series and other micro mixers taken for benchmarking [130].

Dissolve 15 ml. (15-4 g.) of aniline in a mixture of 40 ml. of concentrated hydrochloric acid and 40 ml. of water contained in a 250 ml. conical flask. Place a thermometer in the solution, immerse the flask in a mixture of ice and water, and cool until the temperature of the stirred solution reaches 5°. Dissolve I2 5 g. of powdered sodium nitrite in 30 ml. of water, and add this solution in small quantities (about 2-3 ml. at a time) to the cold aniline hydrochloride solution, meanwhile keeping the latter well stirred by means of a thermometer. Heat is evolved by the reaction, and therefore a short interval should be allowed between consecutive additions of the sodium nitrite, partly to allow the temperature to fall again to 5°, and partly to ensure that the nitrous acid formed reacts as completely as possible with the aniline. The temperature must not be allowed to rise above 10°, otherwise appreciable decomposition of the diazonium compound to phenol will occur on the other hand, the temperature... 

The bimodal profile observed at low catalyst concentration has been explained by a combination of two light generating reactive intermediates in equihbrium with a third dark reaction intermediate which serves as a way station or delay in the chemiexcitation processes. Possible candidates for the three intermediates include those shown as "pooled intermediates". At high catalyst concentration or in imidazole-buffered aqueous-based solvent, the series of intermediates rapidly attain equihbrium and behave kineticaHy as a single kinetic entity, ie, as pooled intermediates (71). Under these latter conditions, the time—intensity profile (Fig. 2) displays the single maximum as a biexponential rise and fall of the intensity which is readily modeled as a typical irreversible, consecutive, unimolecular process ... 

For a single equation, Eqs. (7-36) and (7-37) relate the amounts of the several participants. For multiple reactions, the procedure for finding the concentrations of all participants starts by assuming that the reactions proceed consecutively. Key components are identified. Intermediate concentrations are identified by subscripts. The resulting concentration from a particular reaction is the starting concentration for the next reaction in the series. The final value carries no subscript. After the intermediate concentrations are ehminated algebraically, the compositions of the excess components will be expressible in terms of the key components. 

For the consecutive reactions 2A B and 2B C, concentrations were measured as functions of residence time in a CSTR. In all experiments, C o = 1 lb moPfF. Volumetric flow rate was constant. The data are tabulated in the first three columns. Check the proposed rate equations,... 

Present research is devoted to investigation of application of luminol reactions in heterogeneous systems. Systems of rapid consecutive reactions usable for the determination of biologically active, toxic anions have been studied. Anions were quantitatively converted into chemiluminescing solid or gaseous products detectable on solid / liquid or gas / liquid interface. Methodology developed made it possible to combine concentration of microcomponents with chemiluminescence detection and to achieve high sensitivity of determination. 

Bromine (128 g., 0.80 mole) is added dropwise to the well-stirred mixture over a period of 40 minutes (Note 4). After all the bromine has been added, the molten mixture is stirred at 80-85° on a steam bath for 1 hour, or until it solidifies if that happens first (Note 5). The complex is added in portions to a well-stirred mixture of 1.3 1. of cracked ice and 100 ml. of concentrated hydrochloric acid in a 2-1. beaker (Note 6). Part of the cold aqueous layer is added to the reaction flask to decompose whatever part of the reaction mixture remains there, and the resulting mixture is added to the beaker. The dark oil that settles out is extracted from the mixture with four 150-ml. portions of ether. The extracts are combined, washed consecutively with 100 ml. of water and 100 ml. of 5% aqueous sodium bicarbonate solution, dried with anhydrous sodium sulfate, and transferred to a short-necked distillation flask. The ether is removed by distillation at atmospheric pressure, and crude 3-bromo-acetophenone is stripped from a few grams of heavy dark residue by distillation at reduced pressure. The colorless distillate is carefully fractionated in a column 20 cm. long and 1.5 cm. in diameter that is filled with Carborundum or Heli-Pak filling. 4 hc combined middle fractions of constant refractive index are taken as 3-l)romoaccto])lu iu)nc weight, 94 -100 g. (70-75%) l).p. 75 76°/0.5 mm. tif 1.57,38 1.5742 m.]). 7 8° (Notes 7 and 8). 

Threshold lamit Value - The term refers to toxicity by inhalation. The abbreviation used is TLV. The TLV is usually expressed in units of parts per million (ppm) - i.e., the parts of vapor (gas) per million parts of contaminated air by volume at 25 °C (77°F) and atmospheric pressure. For chemicals that form a fine mist or dust, the concentration is given in milligrams per cubic meter (mg/m ). The TLV is defined as the concentration of the chemical in air that can be breathed for five consecutive eight-hour workdays (i.e., 40 hours per week) by most people without suffering adverse health effiects. This is the definition given by the American Conference of Governmental Industrial Hygienists. 

The formation of resins, tarry matter by consecutive reaction, is prevalent in organic reactions. Figure 3-13a shows the time variations in the concentrations of A, B, and C as given by these equations. The concentration of A falls exponentially, while B goes through a maximum. Since the formation rate of C is proportional to the concentration of B, this rate is initially zero and is a maximum when B reaches its maximum value. 

Consecutive reactions involving one first-order reaction and one second-order reaction, or two second-order reactions, are very difficult problems. Chien has obtained closed-form integral solutions for many of the possible kinetic schemes, but the results are too complex for straightforward application of the equations. Chien recommends that the kineticist follow the concentration of the initial reactant A, and from this information rate constant k, can be estimated. Then families of curves plotted for the various kinetic schemes, making use of an abscissa scale that is a function of c kit, are compared with concentration-time data for an intermediate or product, seeking a match that will identify the kinetic scheme and possibly lead to additional rate constant estimates. 

A truck carr) ing two tanks containing a very unstable and hazardous gas is involved in an accident that results in tlie consecutive explosion of the tanks -one innncdiately, the second approximately a minute later. The total mass of tlie emission resulting from the explosion of each tank is 30,000 g. The wind velocity is 1 m/s from the north, and tlie effective height of emission is 30 meters at the time of tlie accident. Calculate the concentration of tliis gas at 500 meters south but 100 meters east from the site 10 minutes after tlie explosion of tlie first tank. Assume tliat stability category D applies. 

The higher activity of the catalyst [(mall)Ni(dppmo)][SbFg] in [BMIM][PFg] (TOF = 25,425 h ) relative to the reaction under identical conditions in CFF2C12 (TOF = 7591 h ) can be explained by the fast extraction of products and side products out of the catalyst layer and into the organic phase. A high concentration of internal olefins (from oligomerization and consecutive isomerization) at the catalyst is known to reduce catalytic activity, due to the formation of fairly stable Ni-olefin complexes. 

The ice-cold fluoboric acid solution is added rather rapidly, with stirring, to the finished tetrazo solution, the temperature being kept below io°. A thick paste of 4,4 -biphenylene-bis-diazonium borofluoride forms. The mixture is stirred at io° for twenty to thirty minutes. It is then collected on a 19-cm. Buchner funnel, and washed consecutively with about 200 cc. of cold water, 200 cc. of cold commercial methyl alcohol, and 200 cc. of commercial ether the cake is sucked as dry as possible between washings. It is then dried in a vacuum desiccator over concentrated sulfuric acid (sp. gr. 1.84). The yield of the dry solid is 393 400 g. (68-69 Per cent of the theoretical amount). The product decomposes at 135-1370. 

Fig. 1. Dependence of relative concentrations Cj on time variable r (arbitrary units) for consecutive catalytic reaction...

The procedure for solving the relations between concentrations has been used in kinetic studies of complex catalytic reactions by many authors, among the first of them being Jungers and his co-workers 17-20), Weiss 21, 22), and others [see, e.g. 23-25a). In many papers this approach has been combined with the solution of time dependencies, at least for some of the single reactions. Also solved were some complicated cases [e.g. six-step consecutive reaction 26,26a) 3 and some improvements of this time-elimination procedure were set forth 27). The elimination of time is... 

In the case of coupled heterogeneous catalytic reactions the form of the concentration curves of analytically determined gaseous or liquid components in the course of the reaction strongly depends on the relation between the rates of adsorption-desorption steps and the rates of surface chemical reactions. This is associated with the fact that even in the case of the simplest consecutive or parallel catalytic reaction the elementary steps (adsorption, surface reaction, and desorption) always constitute a system of both consecutive and parallel processes. If the slowest, i.e. ratedetermining steps, are surface reactions of adsorbed compounds, the concentration curves of the compounds in bulk phase will be qualitatively of the same form as the curves typical for noncatalytic consecutive (cf. Fig. 3b) or parallel reactions. However, anomalies in the course of bulk concentration curves may occur if the rate of one or more steps of adsorption-desorption character becomes comparable or even significantly lower then the rates of surface reactions, i.e. when surface and bulk concentration are not in equilibrium. 

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