Ethanol/acetic acid separation

Erlang distribution, residence time, 558 Equation of state, gases, 91 density calculation, 91 Ethanol/acetic acid separation, 385 Ethanol/butanol equilibria, 375 Ethanol/isopropanol/water separation, 421... 

Extraction of water from an aqueous solution of ethanol Extraction of water from solutions of alcohols and acetone Extraction of water from an aqueous solution of ethanol Extraction of water from solutions of ethanol, pyridine Separation of Cs isomers Separation of benzeneM-heptane Extraction of water from an aqueous solution of ethanol Extraction of water from solutions of ethanol, acetic acid Separation of dichloroethane/trichloroethylene mixtures Extraction of water from solutions of ethanol, acetic acid Extraction of water from an aqueous solution of ethanol Extraction of water from an aqueous solution of ethanol Extraction of 1 -propanol, ethanol from an aqueous solution Extraction of water from solutions of ethanol and acetic acid... 

Separation of organic/organic mixtures Extraction of water from an aqueous solution of ethanol Extraction of water from solutions of ethanol, acetic acid Separation of benzene/ -hexane mixtures Separation of xylene isomers... 

Kirchner s book 1127 gave an overview on the TLC of antihistamines, and Boonen 1128] also dealt with the separation of various antihistamines using plain silica and a mixture of ethanol/acetic acid/water (5 3 2). Recent experiments used metal ion impregnated silica layers to improve the separation of antihistamines 1129-1311. Antihistamines are easily visualised by iodine vapour. Separation of seven antihistamines on plain silica as well as metal ion impregnated silica with a benzene/butanol/acetic acid/water (7 8 5 2) mixture is shown in Table 10.18. Metal ion impregnation improved the separation of these antihistamines, especially when two or more stationary phases were used for parallel separations. 

Furthermore, it is seen that a hydroxyl group in the molecule does not necessarily reduce the Rf value as the chromatographic behavior of serine with respect to glycine on both layers of silica gel and cellulose shows (see Table 1). Some of the numerous eluents that have been used for the separation of amino adds on silica gel are acetone-water-acetic acid-formic acid (50 15 12 3), ethylacetate-pyridine-acetic acid-water (30 20 6 11), 96% ethanol-water-diethylamine (70 29 1), chloroform-formic acid (20 1), chloroform-methanol (9 1), isopropanol-5 % ammonia (7 3), and phenol-0.06M borate buffer pH 9.30 (9 1). On cellulose plates, ethylacetate-pyridine-acetic add-water (5 5 1 3), n-bu-tanol-acetic acid-water (4 1 1 and 10 3 9), n-butanol-acetone-ammonia-water (20 20 4 1), collidine-n-bu-tanol-acetone-water (2 10 10 5), phenol-methanol-water (7 10 3), ethanol-acetic acid-water (2 1 2), and cyclohexanol-acetone-diethylamine-water... 

Fig. 4 Countercurrent separation of various samples by the coil planet centrifuge, (a) Separation of basic dyes with an organic/aqueous two-phase solvent system. M.G. methyl green M.B. methylene blue N.R. neutral red F.B. basic fuchsin. (From Ref. [3].) Solvent system consisted of isoamyl alcohol/ethanol/acetic acid/water (4 2 1 5, v/v).

Fig. 4a shows countercurrent chromatographic separation of four basic dyes, i.e., methyl green (MG), methylene blue (MB), neutral red (NR), and basic fuchsin using a two-phase solvent system composed of isoamyl alcohol-ethanol-acetic acid-distilled water (4 2 1 5, v/v). The first coil displays the separation of the mixture, and the other coils show distribution of individual dyes to demonstrate the reproducibility of the method. The separation was performed with 6 m of 0.35-mm-lD tubing (ca. 300 helical turns) at relative coil rotation of 0.25 rpm at 300 X g for 10 hr. 

Extraction of water from solutions of ethanol and acetic acid, separation of benzene/cyclohexane and acetone/ cyclohexane mixtures Extraction of ethanol from an aqueous solution... 

The first liquid-solid separation of the corticosteroids was carried out using a silica stationary phase with a mobile phase of chloroform-dioxane (100 5) to separate cortisol, cortisone and 11-de-oxycortisol (Touchstone and Wortmann, 1973). Most separations using silica stationary phases have used variations of the mobile phase originally described by Hesse and Hovermann (1973). Thus, a mobile phase of dichloromethane-ethanol-water (93.6 4.7 1.7) has been used to resolve prednisolone, cortisol, prednisone, cortisone, corticosterone, deoxycortisol and 17-a-hydroxy-progesterone on a silica stationary phase (Trefz et al., 1975). Other mobile phases which have been used include hexane-methylene chloride-ethanol-acetic acid (63.8 30 6 0.2) for the determination of plasma prednisolone (Loo et al., 1977), a mixture of 1.5% methanol and 0.2% water in chloro-... 

Figure 1.1 Separation of complex standard lipid mixtures on a 20 cm x 20 cm high-performance thin-layer chromatography plate using four developments. The first development was up to a distance of 5 cm above the origin in the solvent system ethyl acetate/1-propanol/chloroform/ methanol/0.025% KCl, 25 25 25 10 9 vol./vol. The second development was up to 8 cm above the origin in the solvent system toluene/ether/ethanol/acetic acid, 60 40 1 0.23 vol./vol. The third development was to the full length (9 cm) in the solvent system hexane/diethyl ether, 94 6 vol./ vol., followed by the last development to full length in hexane. The plates were freed of solvent between developments by blowing with hot air. Reproduced with permission from Yao, J. K. and Rastetter, G. M., Microanalysis of complex tissue lipids by high-performance thin-layer chromatography, Analytical Biochemistry, 150, 111-16.

Ma, Xu, Liu, and Sun (2010) used perfluorosulfonic acid-poly(vinyl alcohol)-Si02/ poly(vinyl alcohol)/polyacrylonitrile (PFSA-PVA-Si02/PVA/PAN) bifunctional hollow-fiber composite membranes. The catalytic and the selective layer of the membrane were independently optimized. These membranes were synthesized by dipcoating. The performance of these bifunctional membranes was evaluated by dehydrating the ternary azeotropic composed of a water, ethanol, and ethyl acetate system (top product of a reactive distillation process of esterification of acetic acid with ethanol), obtaining separation factors of water/ethanol up to 379. An extensive assessment on the esterification reaction of ethanol-acetic acid was later published (Lu, Xu, Ma, Cao, 2013). In this case, the reaction equilibrium was broken in less than 5 h, and a 90% conversion of acetic acid was achieved after 55 h. 

The 9- and 13-hydroperoxides of methyl linoleate were separated on a silica column (Z = 205 nm) using a 99.5/0.5 hexane/IPA mobile phase [691]. For the systems that contained vitamin E, only the two peaks were obtained (all the same isomer). However, when the oxidation product was generated without vitamin E present, the appearance of cis-tmns and truns-tmns isomers occurred. Complete resolution of all isomers was not achieved. In all cases elution was complete in 10 min. Similarly, the peroxidation products of linoleic acid, 9- and 13-hydroperoxy-linoleic acids, were separated on a silica column (2 = 234 nm) using a 98/1.9/0.1 hexane/ethanol/acetic acid mobile phase [692]. Elution was complete in < 11 min. The peaks were incompletely resolved. The stock solutions were 4mM. 

If the solvent is water or if it contains water, the bimolecular (collision) processes between a neutral substrate and a charged nucleophile (such as nucleophilic acyl addition reactions and nucleophilic displacement with alkyl hahdes) are slower due to solvation effects. On the other hand, water is an excellent solvent for the solvation and separation of ions, so unimolecular processes (which involve ionization to carbocations see Chapter 11, Section 11.6) may be competitive. If the solvent is protic (ethanol, acetic acid, methanol), ionization is possible, but much slower than in water. However, ionization can occiu- if the reaction is given sufficient time to react. In other words, ionization is slow, but not impossible. An example of this statement is the solvolysis of alcohols presented in Chapter 6 (Section 6.4.2). Based on this observation, assume that ionization (unimolecular reactions) will be competitive in water, but not in other solvents, leading to the assumption that bimolecular reactions should be dominant in solvents other than water. This statement is clearly an assumption, and it is not entirely correct because ionization can occur in ethanol, acetic acid, and so on however, the assumption is remarkably accurate in many simple reactions and it allows one to begin making predictions about nucleophilic reactions. 

The Pyrrole-C-carboxylic acids have been separated likewise on silica gel G layers with the help of two-dimensional TLC [4] solvents were n-butanol-ethanol-concentrated ammonium hydroxide-water (40 + 40 + 4+8) and ethyl acetate-ethanol-acetic acid (60 + 12 + 20). 

An alternative method of separation is to sorb all the anions on a strongly basic anion exchanger hydroxide and to elute the short-chain sulphonates with at least 30 bed-volumes of 1 M aqueous hydrochloric acid. If soap is present, elute the fatty acids first with at least 12 bed-volumes of 1 M ethanolic acetic acid, followed by a wash with 5 bed-volumes of water. 

Keller et al. (1984). separated eross-linking amino acids of elastin by two-dimensional silica gel TLC using butanol-acetic acid-water (4 1 1) and propa-nol-NH,-water (8 1 11). Schwartz (1984) detected as little as 60 pmol of histidine phenylthiohydantoin by UV (366 nm) irradiation on a fluorescein-containing silica gel plate after development with ethanol-acetic acid (7 3). Henderson et al. (1985) reported that two-dimensional TLC was useful for screening aspartyl-glycosaminuria in the urine of children by heating ninhydrin-stained plates at 120°C. 

Silica gel or cellulose TLC is often used for the determination of pantothenic acid in multivitamin preparations and mixed feeds. Ganshirt and Malzacher (1960) separated pantothenic acid on silica gel G plates with the mobile phase acetic acid-acetone-menthol-benzene (5 5 20 70). Thielemann (1974) used activated commercial silica gel sheets to separate pantothenic acid in multivitamin preparations. Puech et al. (1978) used silica gel GF254 layers to separate calcium pantothenates, pantolactone, and other degradation products of pantothenic acids from pharmaceutical preparations the mobile phase used was chloroform-ethanol-acetic acid (10 7 3). Baczyk and Szczesniak (1975) separated the B-complex vitamins, including pantothenic acid, on cellulose MN300HR layers with -butanol-acetic acid-water (8 1 11) as the mobile phase. 

Sometimes it is possible to separate a mixture of lichen substances by their different solubility. Usnic acid and atranorin are very soluble in chloroform, but nearly insoluble in methanol. Suitable solvents for recrystallization are n-hexane, benzene, diethyl ether, acetone, ethyl acetate, methanol, ethanol, acetic acid, dioxane or water often mixtures of these solvents are used. Sugar and low molecular carbohydrates are well known for their poor tendency to crystallize. Very important is the use of diethyl ether and dioxane free from peroxides, which are highly explosive. A simple reaction to test these solvents for peroxides is to shake about 3 ml of... 

Block distinguished between classes of surfactants using two TLC systems (8). The first used Silica Gel G F-254 with 90 10 ethanol/acetic acid. For visualization, the upper part of the plate was sprayed with pinacryptol yellow to detect anionic surfactants and soap, while the lower portion was sprayed with Dragendorff reagent to detect nonionics and cationics. For further separation of nonionics and cationics, a Silica Gel G plate was used with 80 19 1 methanol/chlorofoim/0.05 M sulfinic acid. Detection was by spraying with palatine blue solution. For exact characterization, the spots were removed, eluted with solvent, and the surfactants identified by IR spectroscopy. 

The following chiral reagents were employed for diastereomer formation before sample application and chromatography on silica gel or silica gel G TLC plates (L)-leucine Af-carboxyanhydride for D,L-dopa-carboxyl- " C separated with ethyl acetate/formic acid/water (60 5 35) mobile phase and detected by ninhydrin [7 f 0.38 (d)/0.56 (l)] [43] Af-trifluoroacetyl-L-prolyl chloride for D,L-amphetamine separated with chloroform/methanol (197 3) and detected by sulfuric acid/formaldehyde (10 1) (Rf 0.49 (d)/0.55 (l)) [44] Af-benzyloxycarbonyl-L-prolyl chloride for D,L-methamphetamine separated with n-hexane/ethyl acetate/acetonitrile/diisopropyl ether (2 2 2 1) and detected by sulfuric acid/formaldehyde (10 1) [/ f 0.57 (l)/0.61 (d)] [44] (l/ ,2/ )-(-)-l-(4-nitrophenyl)-2-amino-1,3-propanediol (levobase) and its enantiomer dextrobase for chiral carboxylic acids separated with chloroform/ethanol/acetic acid (9 1 0.5) and detected under UV (254 nm) light R[ values 0.63 and 0.53 for 5- and / -naproxen, respectively) [45] (5)-(4-)-a-methoxyphenylacetic acid for R,S-ethyl-4-(dimethylamino)-3-hydroxybutanoate (carnitine precursor) with diethyl ether mobile phase [/ f 0.55 R)/0J9 (5)] [46] and (5)-(4-)-benoxaprofen chloride with toluene/acetone (100 10, ammonia atmosphere) mobile phase and fluorescence visualization (Zeiss KM 3 densitometer 313 nm excitation, 365 nm emission) (respective R values of R- and 5-isomers of metoprolol, oxprenolol, and propranolol were 0.24/0.28, 0.32/0.38, and 0.32/0.39) [47]. 

Acetylation. Heat i g. of />-nitrophenol with 5 ml. of an acetic acid-acetic anhydride mixture under reflux for 15 minutes. Pour into water the solid acetate separates. Filter, wash with water and re-crystallise from ethanol m.p. 77 5°. This treatment usually leaves o-nitrophenol unchanged. The addition, however, of about 0 5 ml. of cone. H2SO4 to the acetylating mixture gives the o-derivative, m.p. 40°. 

The above diamines can alternatively be identified as their diacetyl derivatives. Heat under reflux 0 5 g. of the diamine with 3 ml. of acetic acid—NaOH solution will cause the separation of the diacetyl derivative. Recrystallise from ethanol. M.ps. of the diacetyl derivatives of 0-, m-, and />-phenylene diamine are 185 , 191 , and 304 respectively (p. 551). 

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