Acetic-acid/water separation

Acrylonitrile based membranes were also used in acetic acid-water separation. Lee and Oh [11] copolymerized 4-vinylpyridine with acrylonitrile in order to prepare a membrane for the dehydration of water-acetic acid mixture by pervaporation. Yoshikava et al. [25] reported that membranes prepared from poly (acrylic acid-co-acrylonitrile)... 

Lu, S.Y., Huang, H.Y. and Wu, K.H. 2001. SiUcalite/poly(dimethylsiloxane) nanocomposite pervaporation membrabnes for acetic acid/water separation. 16(11) ... 

Xanthylamides. Dissolve 0 25 g. of xanthhydrol in 3-5 ml. of glacial acetic acid if an oil separates (as is sometimes the case with commercial material), allow to settle for a short time and decant the supernatant solution. Add 0-25 g. of the amide, shake and allow to stand. If a crystalline derivative does not separate in about 10 minutes, warm on a water bath for a period not exceeding 30 minutes, and allow to cool. Filter oflF the solid xanthylamide (9-acylamidoxanthen) and recrystallise it from dioxan - water or from acetic acid - water, dry at 80° for 15 minutes and determine the m.p. 

Added 112 grams sassafras oil. Shake for a couple of minutes. You get an orangish emulsion. Clears within 15 minutes forming two layers, bottom layer oil, top layer acetic acid, eugenol + the other solubles. Separated the oil from the others, washed the oil layer 2x with fresh C//-/2O. Weight after acetic acid water washes 101.5 (-10.5 grams). 

Sodium acetate reacts with carbon dioxide in aqueous solution to produce acetic anhydride and sodium bicarbonate (49). Under suitable conditions, the sodium bicarbonate precipitates and can be removed by centrifugal separation. Presumably, the cold water solution can be extracted with an organic solvent, eg, chloroform or ethyl acetate, to furnish acetic anhydride. The half-life of aqueous acetic anhydride at 19°C is said to be no more than 1 h (2) and some other data suggests a 6 min half-life at 20°C (50). The free energy of acetic anhydride hydrolysis is given as —65.7 kJ/mol (—15.7 kcal/mol) (51) in water. In wet chloroform, an extractant for anhydride, the free energy of hydrolysis is strangely much lower, —50.0 kJ/mol (—12.0 kcal/mol) (51). Half-life of anhydride in moist chloroform maybe as much as 120 min. Ethyl acetate, chloroform, isooctane, and / -octane may have promise for extraction of acetic anhydride. Benzene extracts acetic anhydride from acetic acid—water solutions (52). 

Because of its volatility, the cobalt catalyst codistills with the product aldehyde necessitating a separate catalyst separation step known as decobalting. This is typically done by contacting the product stream with an aqueous carboxyhc acid, eg, acetic acid, subsequently separating the aqueous cobalt carboxylate, and returning the cobalt to the process as active catalyst precursor (2). Alternatively, the aldehyde product stream may be decobalted by contacting it with aqueous caustic soda which converts the catalyst into the water-soluble Co(CO). This stream is decanted from the product, acidified, and recycled as active HCo(CO)4. 

Acids that are solids can be purified in this way, except that distillation is replaced by repeated crystallisation (preferable from at least two different solvents such as water, alcohol or aqueous alcohol, toluene, toluene/petroleum ether or acetic acid.) Water-insoluble acids can be partially purified by dissolution in N sodium hydroxide solution and precipitation with dilute mineral acid. If the acid is required to be free from sodium ions, then it is better to dissolve the acid in hot N ammonia, heat to ca 80°, adding slightly more than an equal volume of N formic acid and allowing to cool slowly for crystallisation. Any ammonia, formic acid or ammonium formate that adhere to the acid are removed when the acid is dried in a vacuum — they are volatile. The separation and purification of naturally occurring fatty acids, based on distillation, salt solubility and low temperature crystallisation, are described by K.S.Markley (Ed.), Fatty Acids, 2nd Edn, part 3, Chap. 20, Interscience, New York, 1964. 

Separated from retinol by column chromatography on water-deactivated alumina with hexane containing a very small percentage of acetone. Also chromatographed on TLC silica gel G, using pet ether/isopropyl ether/acetic acid/water (180 20 2 5) or pet ether/acetonitrile/acetic acid/water (190 10 1 15) to develop the chromatogram. Then recrystd from propylene at low temperature. 

It has been demonstrated that the chromatographic separation, on filter paper, of the corresponding sugar from the products of condensation of ethyl acetoacetate with hexoses and pentoses is possible. The solvent mixture used (butanol-acetic acid-water) displaced all the products of condensation at the same rate.17... 

Grade M Ascending Butanol/acetic acid/water (4 1 5) Not available Separation of B and C as acetyl derivatives 212... 

Clarke-Othmer process, for acetic acid-water for ethanol separation, 5 834 Claros Diagnostics, 26 976 Class 4A inert ingredients, 14 126 Classes A-C radioactive waste, 25 853 disposal of, 25 857 Classical least squares, 6 39-41 Classical thermodynamics, 24 641-642 Classification bauxite, 2 353... 

Clarke-Othmer process for acetic acid-water for ethanol separation, 8 834 in cocoa shell from roasted beans,... 

The resultant resins were separately treated with trifluoro-acetic acid water (95 5 v/v) (2 mL) for 5 min at ambient temperature and filtered. In each case, the filtrate was collected into a preweighed test tube. The resin was washed with an... 

A recent paper [69] presents a new type of PVA hybrid membrane prepared by hydrolysis followed by condensation of a PVA and a tetraethylorthosilicate (TEOS) mixture, which shows a significant performace in water-acetic acid mixture separation. The highest separation selectivity (1116) with a flux of 3.33xft)"2 kg m"2 h"1 at 30 °C for 10% mass of water in the feed has ben obtained by using the membrane containing 1 2 mass ratio of PVA and TEOS. The performance of these membranes was explained on the basis of a reduction of free volume and a decrease of the hydrophylic character owning to the formation of... 

Another recent work presents the possibility to use a membrane made by PVA-g-acrylonitrile (AN) to separate acetic acid/water mixtures by pervaporation [70], The best separation factor (14.6) has been obtained by using PVA-g-AN (52 %) membrane, at 30°C, 90 % acetic acid in the feed. The permeation rate was 0.09 kg m"2h 1. 

Separates monosaccharides and disaccharides. Especially useful for methyl glycosides and sugar alcohols. Gives good separation with mono-, di-, tri- and oligosaccharides. Used as second solvent after n-butanol/acetic acid/water (SG)... 

Two-dimensional techniques are usually employed if both phospho-glycerides and glycolipids are present, but it is possible to resolve members of both classes using a diisobutylketone-acetic acid-water mixture (40 25 5). A solvent composed of acetone, acetic acid and water (100 2 1) will separate the mono- and di-galactosyldiglycerides, which are particularly abundant in plant extracts, from phosphoglycerides, which remain at the origin. 

Because of the diaphoretic and laxative effects, the composition of Sambuci flos (Sambucus negra L., black elder) has been extensively investigated by TLC. Samples for TLC analysis were preparated by refluxing 1.0 g of air-dried, powdered flowers of Sambucus negra with 10 ml of methanol for 30 min. The suspension was filtered, and the filtrate was concentrated and redissolved in 5 ml of methanol. Separation was performed on silica layers using 10 different mobile phases 1 = ethyl acetate-formic acid-acetic acid-water (100 11 11 27, v/v) 2 = ethyl acetate-formic acid-water (8 1 1, v/v) 3 = ethyl acetate-formic acid-water (88 6 6, v/v) 4 = ethyl acetate-methyl-ethyl ketone-formic acid-water (50 30 10 10, v/v) 5 = ethyl acetate-methyl-ethyl ketone-formic acid-water (60 15 3 2, v/v) 6 = ethyl acetate-formic acid-acetic acid-methyl-ethyl... 

The diuretic and cholagog effect of Ononis arvensis motivated the development of a new two-dimensional paper chromatographic and TLC method for the measurement of onion in its roots and aerial parts. Samples were dried, ground and extracted with methanol (70 per cent, w/v) for 2 h. The supernatant was diluted and used for TLC separation on a cellulose stationary phase. The first eluent was 3 per cent formic acid, and the second was n-butanol-acetic acid-water (4 1 5, v/v) for both TLC and paper chromatography. Spots were scraped off, extracted with methanol and the absorption was measued at 260 nm. It was found that the average ononin content in roots and aerial parts was 0.153 0.0278 (per cent) and 0.498 0.045 (per cent), respectively. Because of the simplicity, the method was... 

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