Butanol/water separation

The first partial chiral resolution reported in CCC dates from 1982 [120]. The separation of the two enantiomers of norephedrine was partially achieved, in almost 4 days, using (/ ,/ )-di-5-nonyltartrate as a chiral selector in the organic stationary phase. In 1984, the complete resolution of d,l-isoleucine was described, with N-dodecyl-L-proline as a selector in a two-phase buffered n-butanol/water system containing a copper (II) salt, in approximately 2 days [121]. A few partial resolutions of amino acids and dmg enantiomers with proteic selectors were also published [122, 123]. 

X 150 mm column. The derivatives of methanol, ethanol, 1-propanol, and 1-butanol were separated using a mobile phase of 65% acetonitrile and 35% water, with a flow rate of 1 siL/min. The derivatives of the alkyl bromides were separated using a linear program from 10% acetonitrile and 90% water to 50% acetonitrile and 50% water in 20 min. The flow rate was 1 siL/min. 

Diluted in neutraUzed water, separation on CIS Novapak using gradient elution using methanol and phosphate buffers at pH 7 Formation of ion pairs with cetylpyridinium chloride (CeCl) in water and extraction in butanol, separation on C8 Spherisorb using gradient of acetonitrile, methanol, CeCl/phosphate buffer... 

Isoperibolic calorimetry measurements on the n-butanol/water and n-butoxyethanol/water systems have demonstrated the accuracy and convenience of this technique for measuring consolute phase compositions in amphiphile/water systems. Additional advantages of calorimetry over conventional phase diagram methods are that (1) calorimetry yields other useful thermodynamic parameters, such as excess enthalpies (2) calorimetry can be used for dark and opaque samples and (3) calorimetry does not depend on the bulk separation of conjugate fluids. Together, the present study and studies in the literature encompass all of the classes of compounds of the amphiphile/CO ydrocarbon/water systems that are encountered in... 

Van de Vaart et al. [45] used a thin-layer chromatographic method for the analysis of miconazole and other compounds in pharmaceutical creams. The drugs in creams were analyzed by thin-layer chromatography on silica gel plates with ether in pentane-saturated chamber or with butanol-water-acetic acid (20 5 2). Both active ingredients and vehicle components were detected and Rf values of 67 active ingredients are tabulated. Additional eluents may be needed to separate certain combinations of ingredients. 

Paper chromatography has been used to separate and detect pseudoephedrine hydrochloride from other pharmacologically active amines. Whatman No. 1 paper developed in n-butanol water 95% acetic acid (4 5 1), n-butanol toluene water 95% acetic acid (10 10 5 5), ethyl acetate water 95% acetic acid (3 3 1), or chloroform water 95% acetic acid (10 5 4) gave Rf values of 0.73, 0.35, 0.57, and 0.52 for pseudoephedrine hydrochloride respectively. Visualization of pseudoephedrine hydrochloride was done by spraying the chromatogram with 0.5% bromcresol green in methanol or 0.2% nin-hydrin in acetic acid butanol 5 95.30... 

Azeotropic and Partially Miscible Systems. Azeotropic mixtures are those whose vapor and liquid equilibrium compositions are identical. Their x-y lines cross or touch the diagonal. Partially miscible substances form a vapor phase of constant composition over the entire range of two-phase liquid compositions usually the horizontal portion of the x-y plot intersects the diagonal, but those of a few mixtures do not, notably those of mixtures of methylethylketone and phenol with water. Separation of azeotropic mixtures sometimes can be effected in several towers at different pressures, as illustrated by Example 13.6 for ethanol-water mixtures. Partially miscible constant boiling mixtures usually can be separated with two towers and a condensate phase separator, as done in Example 13.7 for n-butanol and water. 

The paper-chromatographic properties of the common deoxy and dideoxy sugars have been treated in several reviews,2 28 a book,829 and individual publications. Common solvent-systems are 6 4 3 1-butanol-pyridine-water (Solvent A) 4 1 5 1-butanol-acetic acid-water (Solvent B) and 1-buta-nol-ethanol-water (4 1 5, upper phase, Solvent C or 3 1 1, Solvent D). The four 2-deoxy-D-hexoses and the 2,6-dideoxyhexoses may be separated as their borate complexes. 0 The use of 1-butanol-water on the one hand, and of 2-butanone-borate buffer on the other, usually provides adequate separation and, by use of a combination of solvents, these deoxy sugars may be identified. 80 The use of buffered systems has proved highly advantageous in the separation and identification of the isomeric 6-deoxy-hexoses.8 1 Other systems, such as Solvent A and 2 1 2 ethyl acetate-... 

The solvent system most suitable for separating Trevespan on HPTLC pre-coated plates cellulose consists of tert. butanol/water/25 ammonia in a ratio of 80/20/1 by volume, whilst for HPTLC pre-coated plates silica gel 60 the best mixture is n-hexane/ethyl acetate/formic acid in the ratio 40/60/0,5. Prior to the separation proper, the HPTLC pre-coated plates were adjusted to a relative humidity of 20. Quantities of o.73 pi of a "test solution in methanol, composed as follows, were applied to the plates and migrated over 5 cm ... 

ETBE is recovered as the bottoms product of the distillation unit. The ethanol-rich C4 distillate is sent to the ethanol recovery section. Water is used to extract excess ethanol and recycle it back to process. At the top of the ethanol/water separation column, an ethanol/water azeotrope is recycled to the reactor section. The isobutene-depleted C4 stream may be sent to a raffinate stripper or to a molsieve-based unit to remove oxygenates such as DEE, ETBE, ethanol and tert-butanol. 

The catalytic cycle for the asymmetric dihydroxylation is shown in Figure 20. The reaction is carried out in a 1/1 t-butanol/water mixture to solubilize the potassium ferricyanide/potassium carbonate used as the oxidant. The solvent mixture, normally miscible, separates into two liquid phases upon addition of the inorganic reagents. 

FIG. 13-89 Separation of butanol-water with heterogeneous azeotropic distillation. 

Table I. Electromotive Force Measurements of the Galvanic Cell Containing Hydrobromic Acid in Ethanol—Water and tert-Butanol—Water Solvents, and in the Separate Solvent Components...

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... 

Similarly, enantiomeric mixtures of carboxylic acid esters can be separated using transesterification (Fig. 22). An n-butanol/water biphasic medium aryloxypropionic acid methyl ester vras transesterified stereoselec-tively, yielding the butylester of the R enantiomer (69). 

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