System ethyl acetate-isopropanol

Illustration 13. Predict the initial distribution coefficient and selectivity for the system water (A)-ethyl acetate ( )-isopropanol (C). 

Simpler separations use PEI in ammonium bicarbonate to separate 3 5 or 2 5 dinucleosides monophosphates (43) or PEI-cellulose and water (44) silica gel in phosphate buffer at neutral pH (45) or silica gel, chloroform-methanol-water or ethyl acetate-isopropanol-water (46). Many of these simpler systems line the NMPs in the midline. Liao (47) separated pyr/gua dinucleotides on PEI and 0.8 LiCI-acetic acid. 

For day-to-day process monitoring and assay of the synthesis related impurity levels it proved more convenient to use a thin layer chromatographic assay [with an elution system comprising ethyl acetate (100), isopropanol (60), water (32), and ammonia (8)] than to use HPLC. 

Solubility in the solvent selected for application Currently the organic solvent are replaced with water as a suspension system, although certain types of film coatings may require organic solvents to be used. Commonly used solvents include alcohols (methanol, ethanol, and isopropanol), esters (ethyl acetate and ethyl lactate), ketones (acetone), and chlorinated hydrocarbons (dichlo-romethane and trichloroethane). 

We have published a demonstration of this strategy for an isopropanol-based aluminum-titanate sol-gel system.The seleeted addition of ethyl acetate was effective at preventing striation formation for the aluminum-titanium recipe. More... 

The character of the anhydrous phase resulting after the desolvation process has taken place can be effectively understood using DSC analysis. In many cases, loss of solvation or hydration molecules leads to the formation of an amorphous material, but this is not always the case. It was established that the acetone, isopropanol, and ethyl acetate solvates of cyclopenthiazide all reverted to Form I (a known anhydrous phase) above the endotherm corresponding to loss of solvent [108]. In other systems, loss of solvation results in the formation of a metastable phase, which undergoes a phase conversion to the stable anhydrate phase before overall melting takes place. Such behavior is illustrated in Fig. 8, where it was reported that the tert-butanol and dioxane solvates of piretanide exhibited a recrystallization after desolvation, but that the propylene glycol and dimethylformamide solvates did not [109]. 

For proving the homogeneity of radioactively labelled eucomin and degradation products. Dewick (19) used five different solvent systems (A) benzene-ethyl acetate-methanol-petroleum ether (b. p. 60—80°) (6 4 1 8) (B) toluene-ethyl formate-formic acid (5 4 1) (C) chloro-form-isopropanol (10 1) (D) benzene-ethyl acetate-methanol-petroleum ether (b.p. 60—80°) (6 4 1 3) (E) benzene-ethanol (92 8). 

Solution. Isopropanol (C)-ethyl acetate B). An azeotrope for this system is reported ( International Critical Tables ) at 74.8 C., 760 mm. Hg, with xc = 0.305. 

Illustration 14. Predict the initial distribution coeflScient in the water (-4)-ethyl acetate (B)-isopropanol (C) system at 20 C. in terms of weight fraction concentration units. 

No solvent system resolves all the Dns-amino acids by ID chromatography. Also, 2D chromatography requires more than two runs for a complete resolution. The eluents most commonly used on polyamide layers are benzene-acetic acid (9 1), toluene-acetic acid (9 1), toluene-ethanol-acetic acid (17 1 2), water-formic acid (200 3), water-ethanol-ammonium hydroxide (17 2 1 and 14 15 1), ethylacetate-ethanol-ammonium hydroxide (20 5 1), n-heptane-n-buta-nol-acetic acid (3 3 1), chlorobenzene-acetic acid (9 1), and ethylacetate-acetic acid-methanol (20 1 1). On silica plates, acetone-isopropanol-25 % aqueous ammonia (9 7 1), chloroform-benzyl alcohol-ethyl acetate-acetic acid (6 4 5 0.2), chloroform-ethyl acetate-acetic acid (38 4 2.8 or 24 4 5), and dichloromethane-methanol-pro-pionic acid (21 3 2) are used. 

Fig. 2 Detection of berberine alkaloids by their green-to-yellow fluorescence under 366 nm UV light using a Digistore-2 Documentation System and by the Bioluminex assay. Lane numbers 1, palmatine 2, berberine 3-8, Mahonia sp. 9-10, Coptis chinensis 11-12, Phellodendron chinen-sis 13 14, Tinospora sp. 15, palmatine plus berberine. Chromatographic conditions HPTLC silica gel 6OF254 Merck plate, toluene-ethyl acet-ate nethanol-isopropanol-water (60 30 20 15 3) mobile phase, 1 p,l test and standard solutions apphed, development in a twin-trough chamber. Sonrce Photograph suppUed by Camag, Muttenz, Switzerland.

Solvent system (I) 1 M ammonium acetate 95% ethanol (3 7, pH 5.0) (II) isobutyric acid ammonia water (66 1.7 33) (III) pyridine water (2 1) (IV) upper layer of n-butanol acetone water (45 5 50) (V) upper layer of n-butanol saturated with 3% ammonia (VI) upper layer of n-butanol saturated with water pyridine (60 1) (VII) upper layer of ethyl acetate formic acid water (60 5 35) (VIII) the solvent consists of 600 g ammonium sulfate in 0.1 M sodium phosphate 2% n-propanol (pH 6.8) (IX) isopropanol cone. HQ water (70 15 15)... 

High conversions of cyclopentene were obtained by Nuetzel et al. [59] with hydroperoxides, inorganic peroxides, or aromatic nitroderivatives. To increase the stability of some tungsten-based catalytic systems, Witte et al. [63] employed a-halogenated alcohols such as chloroethanol, 2-chlorocyclohexanol, bro-moethanol, l,3-dichloro-2-isopropanol, o-chlorophe-nol, and 2-iodocyclohexanol. It was observed that methyl and ethyl acetals of formaldehyde, acetaldehyde, chloroform, and benzaldehyde impart good staiblity to the binary systems of tungsten, whereas epoxides such as ethylene oxide and butylene oxide lead at the same time to an increase in activity and stability. 

Reagents required for the conventional method include sodium hydrogen sulfite (Sigma-Aldrich, cat. no. 243973), hydroquinone (Sigma), NaOH (3M), mineral oil. Wizard DNA Cleanup system (Promega), isopropanol, ammonium acetate (lOAf), glycogen, and ethyl alcohol. 

Melt adhesives and plastisols do not contain solvents. The solution adhesives group includes products made from the following polymer-solvent systems nitrocellulose (typical solvents include solvent combinations usually of a ketone or an ester, an alcohol and a hydrocarbon selected from isopropanol, 2-butylhexanol, amyl acetate, acetone, methyl ethyl ketone), nitrile rubber (main solvent - methyl ethyl ketone), polychloroprene (which is usually dissolved in a mixture of solvents including a ketone or an ester, an aromatic and aliphatic hydrocarbon selected from naphtha, hexane, acetone, methyl ethyl ketone, benzene, toluene), and polyvinyl acetate (water). 

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