Breakthrough method

The packed bed breakthrough method for investigation of mass transfer phenomena in sorbent systems can in many instances offer certain advantages not found in other experimental methods. The method is especially useful when the adsorption isotherms for the principal sorbate exhibit favorable curvature (convex toward loading axis). In such a case, there is the potential for a portion of the sorption front to approach a stable wave form (shape of the front invariant with time). Given the existence of a stable or "steady-state" mass transfer zone (MTZ) and a detailed knowledge of the equilibrium loading characteristics within that zone, one can extract local values of the effective mass transfer resistance at any concentration in the zone. 

Another feature of the breakthrough method is that the uniform geometry of the packed column permits fairly straightforward analysis of the thermal waves produced due to heats of adsorption, and of their effect on the shape of the sorption fronts. The most obvious advantage of this method, however, is the fact that the results of the breakthrough experiments can be applied rather directly to the design of commercial adsorbers, with relatively little analysis of the data. 

This breakthrough method uses 1,2-trans peracetates in the presence of Lewis acids as a promoter to glycosylate (V -I inoc amino acids with an unprotected a-carboxyl group. The deprotection of that glycosylated amino acid carboxyl group prior to incorporation into a peptide can be avoided (62). In addition, the advantage of this method is that the starting materials are readily available... 

The discovery of the oxo (or more accurately, hydroformylation) process was by Ruhrchemie s Roelen who applied for a German patent in 1938. This turned out to be a breakthrough method for both higher and lower alcohols production from the aldehydes. Exploitation of the process, however, was delayed by World War II. It was not until 19 8 that commercialization occurred with the manufacture of isooctyl alcohol by Enjay Chemical Company (1 ). 

The oxo process, discovered in Germany by Otto Roelen, was a breakthrough method of producing primary monohydric alcohols. 

Not all psychedelic amphetamines can be produced in this manner. For instance, B-asarone, the precursor of TMA-2, is a 2propenyl-benzene, rather than an allylbenzene. The breakthrough method will fail in this case, and the Ritter reaction will yield an isoquinoline. To convert... 

Scanning methods described above need not be confined to temperature or flow scanning in chemical kinetics. There may be a variety of other systems, not at all connected with chemical kinetics, where the concept of variablescanning can provide a breakthrough method of data acquisition and lead to a resultant advance in understanding. 

The accuracy of the breakthrough method depends on the ability to detect the surfactant in the mobile phase. A refractive index (RI) detector is most often required since MLC usable surfactants should not absorb UV light. An evaporative light scattering (ELS) detector can also be used successfiilly since most surfactants are solids at room temperature. 

Berthod studied the adsorption of SDS on five different Hypersil stationary phases [11]. Five 10 cm x 4.6 mm i.d. LC columns were specially selected for the study. All experiments were done in a thermostatic bath at 30°C. The amount of SDS adsorbed on the phases was determined by crosschecking the results obtained with (i) the breakthrough method, (ii) controlling the concentration of the effluent solution, and (iii) by the stripping method. The 3 results were in agreement within an 8% experimental error. Figure 4.2 presents the SDS adsorption on bare Hypersil , CPS Hypersil , a cyanopropyl bonded phase, SAS Hypersil , a methyl bonded phase, MOS Hypersil , an octyl bonded phase and ODS Hypersil , an octadecyl bonded phase. The physicochemical properties of these phases are listed in Table 4.1. A very differing behavior was obtained... 

Fig. 1 Hierarchical multiscale, multiparadigm approach to materials modeling, from QM to the mesoscale, incorporating breakthrough methods to handle complex chemical processes (eFF, ReaxFF). Adapted from our multiscale group site http //www.wag.caltech.edu/multiscale...

Detailed analysis of human serum lipoprotein will be one of the most valuable diagnostic tools, since it is considered to be directly related to the detection of fatal diseases, such as heart-attack, diabetes, various liver diseases and so on. However, there has not been a breakthrough method for it. Hara et al. 

The anodic breakthrough method for testing anodized aluminum 500... 

Table 7.2 illustrates typical results obtained with the anodic breakthrough method on eight types of panels, and Table 7.3 compares the observations made after exposing the same types of panels to salt fog testing, Table 7.4 contains corrosion rates determined using the anodic breakthrough method for 2024-T3 specimens that were all anodized in chromic acid with different procedural variants. A wide range of corrosion rates was observed. The worst case was obviously bare aluminum, while lower corrosion rates were observed for specimens that were anodized but not sealed. The lowest corrosion rate was found for coupons anodized and sealed in freshly deionized water at pH 5.5. 

TABLE 7.2 Results Obtained by Testing, with the Anodic Breakthrough Method, Different Types of Anodized Aluminum Panels on 10 Nonoverlapping Positions... 

TABLE 7.4 Comparison of Anodizing (Chromic Acid) Operating Conditions with Corrosion Rates Obtained with the Anodic Breakthrough Method... 

Roberge, P. R., and Ash, P., The Anodic Breakthrough Method for Testing Anodized Alruninrun, Meted Finishing, 93 22-25 (1995). 

The storage of noble gases was demonstrated in some MOFs, though research to date is somewhat limited. Recently, Thallapally et a/. reported that Ni/DOBDC has a Xe capacity of 4.16 mol kg at 100 kPa and 298 K. Moreover, Liu et alP used a colmnn breakthrough method to study the low concentration Xe and Kr adsorption in MOFs. For the first time, their experimental results showed that the Ni/DOBDC was able... 

Gabbott PV, Goth S, Li L. HyperDSC a breakthrough method for materials characterisation. PerkinElmer Applications Note. 

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