Solvent, exchange with

Cellulose activated with ethylenediarnine [107-15-3] is used to prepare high molecular-weight cellulose butyrate (23). Cellulose so activated has a larger measured surface area (120 m /g) than cellulose activated with acetic acid (4.8 m /g). The diamine is removed with water, followed by solvent exchange with acetic acid and butyric acid before esterification. 

Fig. 2.13 Effect of pressure on solvent exchange with M(H20) +, M = V, Mn, Fe, Co and Ni. Reprinted with permission from Y. Duccomun, A. E. Merbach, Inorganic High Pressure Chemistry. (R. van Eldik ed.). Elsevier, Amsterdam, 1986.

As a consequence of redox switch in the polymer layer several phenomena, such as ion and solvent exchange with the electrolyte may change the parameters that determine Zf pf, df = ntf/Apf and the viscoelastic moduli G f and Gf at 10 MHz. 

Using a Wiley mill, wood samples are ground and the 40-60 mesh fraction is Soxhlet-extracted with ethanol benzene (1 2, v/v). Pulp samples are used without size reduction and are solvent exchanged with acetone before drying at 60 °C at 20 mm (Note 1). 

The use of ethylenediamine and NH3 complexes in connection with JHD of dihydrogen complexes has been noted in Section 2-16 and the mechanism of solvent exchange with trans-[Os(en)2(i72-H2)S]2+, S = H20 and MeCN, has been studied.64... 

Under similar acetylation conditions [153], the acetyl content of cotton (4.3%) was more than twice that of ramie (2.1%) or linen (1.3%) cellulose. Mercerization [8,154,155] greatly enhances the reactivity (or accessibility) of cellulose if it is maintained in a never-dried state. Drying of mercerized cellulose considerably reduced its reactivity to even less than half that of the unmercerized samples [8]. However, its impact, can be alleviated by dehydration through a solvent exchange process. The reactivity of mercerized samples expressed by acetyl content increased from 1.7% to 17.7% if water-washed sample was solvent-exchanged with pyridine and to 29% if washing directly with absolute ethanol and a subsequent pyridine exchange. 

Bis(indenyl)ethane-derived ani a-lanthanidocenes [rac-and wera-(CH2)2( -C9H6-l)2LnCl][LiCl(Et20)2] (Ln = Yb, Lu) were synthesized from dilithiated 1,2-bis(indenyl)ethane with either YbCb or LuCb in THF followed by solvent exchange with Et20. In the Yb case, the major diastereomer formed is meso, while in the case of Lu, the rac diastereomer predominated. 

N-Acetyl-3-fluorophenylalanine is charged into a reactor and following pH adjustment and solvent exchange with water, Amano L-acylase (5% by weight) is added. The reaction is stirred at 35— 10 °C until the biotransformation is complete. The mixture is then acidified and filtered. The filtrate is basified and concentrated. The resultant product solution is subjected directly to the Boc protection step. 

Figure 3. Top nigeran single crystals grown from ether. Bottom nigeran single crystals after solvent exchange with methanol.

The organic fractions resulting from all extractions were purified by passage through a column of silica gel, sodium sulfate, and copper powder. Extracts from Methods II, III, IV, and VI were reduced in volume on a Kuderna-Danish apparatus, solvent-exchanged with hexane, and reduced in volume to 1 mL under a stream of nitrogen. The extracts from Methods I, V, and VII were handled similarly but were evaporated to dryness (to remove benzene, toluene, and methanol) before being redissolved in hexane. 

The extracts are concentrated to appropriate volumes and solvent-exchanged with hexane by rotary evaporation and nitrogen blow down. An aliquot of the concentrated extract is then evaporated to dryness and weighed to obtain the total solvent extractable materials (TSEM) or the total oil weight. 

Rates of Solvent Exchange with Solvation Spheres of Metal Ions... 

The formation of a porous structure results from phase separation (or phase inversion) mechanisms that are not limited to electrospraying. It is the process that controls membrane formation, as the solvent exchanges with a nonsolvent, polymer solution solidifies and polymeric device forms. The phase separation is fully investigated in fabrication of flat or hollow fiber membranes or in situ forming drug delivery systems. - Usually, quick evaporation of the solvent produces particles with porous or golf ball-shaped surfaces (Figure 22.26). 

This processing is based on the formation of a three dimensional template of well individualized cellulose whiskers which is filled with a polymer [125,126]. The first step in this process is the formation of a cellulose nanostructure template through a sol/gel process. This involves the formation of an aqueous cellulose nanostructures dispersion which is converted into a gel through solvent exchange with a water miscible solvent (e.g. acetone). In the second step, the cellulose nanostructures template is then filled with a matrix polymer by immersing the gel into a polymer solution. This polymer solvent must be miscible with the gel solvent and does not disperse the cellulose nanostructures. 

Other concepts closer to technical realization are solvent exchange with PEDOTiPSS [87] and a phase-transfer catalysis process [88]. PEDOTiPSS in ethanol with a lower residual water content is commercially available. 

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