Systems, acetic acid-water

In cases where vapor association, or electrolytic dissociation, occurs, the activity coefficients calculated in the ordinary fashion do not approach Raoult s law as the mole fraction approaches 1.0 and show other unusual behavior. The systems acetic acid-water, sodium chloride-water, and acetaldehyde-water are typical of these. 

Solvent Herrmann [93] reported on a water-based system (acetic acid - water) that only gave the aldehyde groups. These results suggest that the conversion of aldehydes to carboxyl groups predominantly takes place in the water phase. Since the presence of water is essential for the latter conversion [4], it is plausible that only the hydrated form of aldehyde intermediate can be oxidized further (Figure 15). 

The largest errors in predicted compositions occur for the systems acetic acid-formic acid-water and acetone-acetonitrile-water where experimental uncertainties are significantly greater than those for other systems. 

Acetic acid-water Pinched system Ethyl acetate, propyl acetate, diethyl ether, dichloroethane, butyl acetate ... 

Acetic acid-water-vinyl acetate Pinched, azeotropic system Self-entraining ... 

In a ternaty hqiiid-hqiiid system, such as the acetic acid-water-MIBK system, all three components are present in both liquid phases. At equilibrium the activity A° of any component is the same in both phases by definition [Eq. (15-6)]. 

FIG. 15-51 Effect of reciprocating speed on HETS, o-xylene-acetic acid-water system. Lo and Pmchazka in Lo et al., p. 377.)... 

A WBL can also be formed within the silicone phase but near the surface and caused by insufficiently crosslinked adhesive. This may result from an interference of the cure chemistry by species on the surface of substrate. An example where incompatibility between the substrate and the cure system can exist is the moisture cure condensation system. Acetic acid is released during the cure, and for substrates like concrete, the acid may form water-soluble salts at the interface. These salts create a weak boundary layer that will induce failure on exposure to rain. The CDT of polyolefins illustrates the direct effect of surface pretreatment and subsequent formation of a WBL by degradation of the polymer surface [72,73]. 

Analysis calculated for C1SH36N2O4S C, 57.41 H, 9.63 N, 7.43 S, 8.51. Found C, 57.60 H, 9.66 N, 7.37 S, 8.25. Thin-layer chromatograms (Note 10) run by the submitters showed a single spot for the product in each of three following solvent systems (solvents, volume ratio of solvents in the same order) chloroform-methanol-acetic acid, 85 10 5, Rf 0.60 1-butanol-acetic acid-water, 4 1 1, Rf 0.58 l-butanol acetic acid-pyridine-water, 15 3 10 12, Rf 0.71. 

Note System layer silica gel 60 F254 (0.25 mm, Merck Art. 5716) developing solvent ethyl acetate-formic acid-acetic acid-water (100 11 11 27). 

York, R. and Holmes, R. C. (1942) Ind. Eng. Chem. 34, 345. Vapor-liquid equilibria of the system acetone-acetic acid-water. 

Singh utilized anionic dyes to detect gramicidin on paper chromatograms184. Paris and Theallet described three paper chromatographic systems for gramicidin185. Ritschel and Lercher described two solvent systems for antibioticsiOD. The solvent systems were butanol-pyridine-acetic acid-water (15 10 3 12) and water saturated butanol-water saturated ethyl ether-acetic acid (5 1 1) on Schleicher and Schull 2043b paper. The antibiotics were visualized by ninhydrin. 

Nussbaumer utilized a solvent system of butanol-acetic acid-water (10 1 3) on acid silica gel G188. Pitton described the following five thin layer systems for several antibiotics including gramicidin189. 

About the same time Beutier and Renon (11) also proposed a similar model for the representation of the equilibria in aqueous solutions of weak electrolytes. The vapor was assumed to be an ideal gas and < >a was set equal to unity. Pitzer s method was used for the estimation of the activity coefficients, but, in contrast to Edwards et al. (j)), two ternary parameters in the activity coefficient expression were employed. These were obtained from data on the two-solute systems It was found that the equilibria in the systems NH3+ H2S+H20, NH3+C02+H20 and NH3+S02+H20 could be represented very well up to high concentrations of the ionic species. However, the model was unreliable at high concentrations of undissociated ammonia. Edwards et al. (1 2) have recently proposed a new expression for the representation of the activity coefficients in the NH3+H20 system, over the complete concentration range from pure water to pure NH3. it appears that this area will assume increasing importance and that one must be able to represent activity coefficients in the region of high concentrations of molecular species as well as in dilute solutions. Cruz and Renon (13) have proposed an expression which combines the equations for electrolytes with the non-random two-liquid (NRTL) model for non-electrolytes in order to represent the complete composition range. In a later publication, Cruz and Renon (J4J, this model was applied to the acetic acid-water system. 

Solvent systems (a) butanol-acetic acid-water (4 1 2) (b) pyridine-butanol-water (1 1 1) (c) collidine-water (3 1) (d) propanol-ethyl acetate-water (7 1 2) all by volume. 

Solvent systems are I=heptane - 2 runs, II=benzene-ethyl acetate (3 1)-2 runs, III=butanol-acetic acid-water (6 1 1), IV=chloroform-methanol (9 1). 

The situation is quite different in the case of an acetic acid-water system. The energy of acetic acid adsorption on platinum is low and therefore the voltammetric curves taken in the absence and in the presence of acetic acid in the supporting electrolyte are nearly the same. However, radiometric data show that C-labeled acetic acid is adsorbed on the electrode surface. Most likely the acetic acid molecules are adsorbed on the top of the water molecules populating the electrode surface. Simultaneously recorded voltammetric and counting rate data are shown in Fig. 8. 

As an example, the system ethyl acetate-acetic acid-water can be used and equilibrium data using the UNIQUAC equation calculated [6]. Using the NRTL equation would have given similar results. 

Fig. 10.2 Liquid-liquid equilibrium for the system ethyl acetate-acetic acid-water at 303 K.

TLC is carried out on a 5 x 20 cm silica gel precoated plate (Merck) with a solvent system of pyridine-ethylacetate-acetic acid-water (75 25 15 30), tert-butanol-acetic acid-water (2 1 1) or n-butanol-acetic acid-water (60 15 25) (11). 

Solvent methanol Solvent system Acetic acid ethylester/Formic acid/Water(100 10 15)... 

Solvent system I Acetic Acid Water (15 85) II Acetic Acid Water (40 60) III Butanol-(l) Acetic Acid Water (4 1 5) upper layer IV Water Butanone(2) MeOH Pentanedione (65 15 15 5)... 

Solvent system I BuOH(l) - Acetic Acid - Water (4 1 5) upper layer II Acetic Acid - Water (4 6) III Ethylacetate - Butanone(2) - Formic Acid - Water (5 3 1 1) ... 

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