Solid-phase loading

The parameter K is a measure of how fast the molecules diffuse across the stagnant liquid film layer. It is assumed that local equilibrium occurs at the exterior solid particle surface. The average solid phase loading, which is only a function of time, is given by ... 

This diffusion coefficient is the mean diffusion coefficient for a solid phase loading ranging from c/ to q2-... 

In antiagglomeration, since the prevention method relies on emulsified water/hydrates, a condensed hydrocarbon is required (Mehta et al., 2003). The solid phase loading cannot exceed 50 volume% of the liquid hydrocarbon phase to prevent high viscosity associated with compacted slurry flow. The emulsion is broken and water is removed onshore or at a platform. 

Figure 10. Limits of solid phase loading in the PSR under the alternative cycle. Parameters (O) one case from series C (figure 5), R=l/3, A, as O but m=8.916 mol kg L Legend marker open end of purge step, closed end of adsorption step...

The equilibrium isothoms were measured for Acid Blue 80 (AB80) and Acid Yellow 117 (AYl 17) on Activated Carbon F400. The Redlich-Peterson isotherm (equation 14) is used to relate equilibrium concentrations between liquid phase and solid phase loading. The values of Kg, og and are 28.32dmVg, 103.6 (dmVmmole) 0.%5 for AB80 on activated carbon and SS.40dmVg, 200.2 (dmvmmole) , 0.910 for AYl 17 on activated carbon. Those isotherm parameters have been used in the multicomponent HSDM to correlate the concentration decay curve. 

The S-PEEK/HPA composite membranes absorb more water than the pure S-PEEK membranes. The W.U. increase associated with the HPAs incorporation into the S-PEEK matrix is only one of the factors affecting the membrane conductivity. The other factors, including the polymer intrinsic conductivity, the strength, density and softness of the solid acid sites, the solid phase loading, the particle size and spatial distribution, the aqueous phase... 

Thus, a novel chiral zirconium complex for asymmetric aza Diels-Alder reactions has been developed by efficient catalyst optimization using both solid-phase and liquid-phase approaches. High yields, high selectivity, and low loading of the catalyst have been achieved, and the effectiveness of chiral catalyst optimization using a combination of solid-phase and liquid-phase methods has been demonstrated. 

Hlasta and Deng have developed a two-step solid-phase method for the decoration of azoles at C-2 [188]. First, imidazole was loaded onto a polystyrene-bound carbamyl chloride via a benzaldehyde bridge (Fig. 40). The 2-substi-tuted imidazole was efficiently cleaved in good yields in the presence of various nucleophiles (i.e., water, alcohols, and amines), trifluoroacetic acid, and boron trifluoride under microwave irradiation in a closed vessel at 120 °C for 5 min. 

To perform the cycloaddition on solid-phase, N-l-unprotected pyrazi-nones were coupled with the solid support by treatment of the brominated linker in DMF for 6h at ambient temperature, using CS2CO3 as a base (Scheme 43). The reaction time for complete loading could be dramatically shortened to only 5 min under microwave irradiation at a pre-selected maximum temperature of 70 °C. 

It is noteworthy that trifluoroacetic acid was introduced as the most appropriate acidifler for column chromatography and solid phase extraction techniques, i.e., low boiling point due to its high acidity, requiring low amounts to reach the respective pH. Also, its high volatility allows easy evaporation thus minimizing the thermal load and acidification during concentration. 

Redox-sensitive resin 24 designed for solid-phase peptide synthesis (SPPS) [29] was prepared from commercially available 2,5-dimethylben-zoquinone in seven steps [30] and loaded to a support via a Wittig reaction. Release of the peptide occurs using two sequential mild conditions, reduction with NaBH4 followed by TBAF-catalyzed cyclic ether formation (Scheme 8) which provide orthogonality to acid sensitive reactions. 

Numerous resin supports are commercially available for solid-phase synthesis and some allow the acquisition of quite reasonable quality spectra of compounds bonded to them - and some don t. The resins to avoid (if you intend trying to monitor your reactions by MAS-NMR) are any that are based purely on cross-linked polystyrene. These are too rigid and afford little or no mobility to any bound compound. These resins are relatively cheap and have high specific loadings but will give very poor spectra even in a MAS probe. We see little point in running spectra of compounds on these resins as the quality of the spectra make them virtually useless - and perhaps worse - potentially misleading. 

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