Ethyl acetate recovery

Hg(II) Fertified river Oxalic-acid- Ethyl acetate Recovery of mercury 52... 

The crude product is best purified by sublimation under reduced pressure (100-110°/1 mm.) (recovery 90-95%). Purification can also be effected by recrystallization from acetone (recovery 80-90%), ethyl acetate (recovery 70-80%), or ethanol (recovery 60-70%). The purified 4-methyl-6-hydroxypyrimidine melts at 148-149°. 

In a 500 ml. wide-mouthed reagent bottle place a cold solution of 25 g. of sodium hydroxide in 250 ml. of water and 200 ml. of alcohol (1) equip the bottle with a mechanical stirrer and surround it with a bath of water. Maintain the temperature of the solution at 20-25°, stir vigorously and add one-half of a previously prepared mixture of 26-5 g. (25 -5 ml.) of purebenzaldehyde (Section IV,115) and 7 -3 g. (9-3 ml.) of A.R. acetone. A flocculent precipitate forms in 2-3 minutes. After 15 minutes add the remainder of the benzaldehyde - acetone mixture. Continue the stirring for a further 30 minutes. Filter at the pump and wash with cold water to eliminate the alkali as completely as possible. Dry the solid at room temperature upon filter paper to constant weight 27 g. of crude dibenzalacetone, m.p. 105-107°, are obtained. Recrystallise from hot ethyl acetate (2-5 ml. per gram) or from hot rectified spirit. The recovery of pure dibenzalacetone, m.p. 112°, is about 80 per cent. 

Methyl acetate Acetic acid Glacial acetic Ethyl acetate column finishing column acid storage recovery coiumn... 

Several examples of cost-effective liquid-hquid extraction processes include the recovery of acetic acid from water (Fig. 15-1), using ethyl ether or ethyl acetate as described by Brown [Chem. Eng. Prog., 59(10), 6.5 (1963)], or the recoveiy of phenolics from water as described by Lauer, Littlewood, and Butler [7/Steel Eng., 46(5), 99 (1969)] with butyl acetate, or with isopropyl ether as described by Wurm [Gliickauf, 12, 517 (1968)], or with methyl isobutyl ketone as described by Scheibel [ Liqmd-Liquid Extraction, in Periy Weiss-... 

When larger runs are made the yields increase thus 2000 cc. of ethyl acetate and 200 g. of sodium give 515-568 g. of ethyl acetoacetate. From a run of this size it is possible to recover about 700 cc. of ethyl acetate. Approximately a proportionate recovery is obtained in smaller runs. 

The vinyl ether may be further purified by dissolving it in 15 ml of dry ether and adding a solution of 0.25 g of lithium aluminum hydride in 10 ml of dry ether. The mixture is refluxed for 30 minutes, and excess hydride is destroyed by addition of ethyl acetate (1 ml). Ice-cold dilute (0.5 N) sulfuric acid (25 ml) is gradually added to the cooled mixture, the ethereal layer is rapidly separated, the aqueous layer is extracted once with 10 ml of ether, and the combined ethereal solution is washed once with water and dried over potassium carbonate. Removal of the solvent, followed by distillation of the residue affords about 85% recovery of the pure vinyl ether, bp 102-10376 mm, 1.5045. 

The checkers dissolved the crude acid in the minimum amount of 2N sodium hydroxide (about 3 ml./g.) and reprecipitated it in 5 portions with IN hydrochloric acid recovery 75-85%. Alternatively, they added the acid to boiling ethyl acetate (9 ml./g.), added decolorizing carbon to the solution, boiled the mixture for 5 minutes, separated the carbon by filtration, and cooled the hot filtrate recovery 45-55%. The checkers found no difference in the infrared spectra of material purified in the two ways, but recrystallized material was reduced more quickly by hydrogen. 

For example, the lycopene available on the market is supplied mainly by LycoRed (www.lycored.com), a company that uses a classical extraction system (ethyl acetate as solvent) and maintains a monopoly position for lycopene production on a large scale. The manufacturing of the Lyc-O-Mato oleoresin (recognized by European Regulation 258/97/EC) product of LycoRed is almost identical to the production of the food additive and includes physical operations to separate the pulp from ripe tomatoes extracted according to GMPs and lSO-9002-certified procedures. The final product contains 6 to 15% lycopene the total lycopene recovery from pulp reaches 85% and from paste around 50%. 

The use of ethyl acetate was suggested by Oszmianski and Lee (1990) to wash out phenolics other than anthocyanins. Finally, a relatively pure anthocyanin extract can be removed from the colnmn with acidified methanol (0.1% HCl). Anthocyanin extracts can be enriched in this way by use of solid phase purification, which is especially helpful for diluted samples such as biological samples. Two factors in the nse of these purification techniques are the stability of anthocyanins to the conditions nsed and the ease of anthocyanin recovery from the column. ... 

Volkov (1994) has given a state-of-the-art review on pervaporation. A number of industrial plants exist for dehydration of ethanol-water and (.vwpropanol-water azeotropes, dehydration of ethyl acetate, etc. There is considerable potential in removing dissolved water from benzene by pervaporation. The recovery of dis.solved organics like CH2CI2, CHCI3, CCI4, etc. from aqueous waste streams also lends itself for pervaporation and pilot plants already exist. 

Product recovery from reversed micellar solutions can often be attained by simple backextraction, by contacting with an aqueous solution having salt concentration and pH that disfavors protein solubilization, but this is not always a reliable method. Addition of cosolvents such as ethyl acetate or alcohols can lead to a disruption of the micelles and expulsion of the protein species, but this may also lead to protein denaturation. These additives must be removed by distillation, e.g., to enable reconstitution of the micellar phase. Temperature increases can similarly lead to product release as a concentrated aqueous solution. Removal of the water from the reversed micelles by molecular sieves or silica gel has also been found to cause a precipitation of the protein from the organic phase. 

A monitoring system has been established to determine 90 pesticides including anilides and 10 related degradation products in river water. Pesticide residues in the water sample are collected on a PS-2 cartridge (265-mg) at a flow rate of 10 mL min, eluted with 3 mL of acetone, 3 mL of n-hexane and 3 mL of ethyl acetate successively, and determined by GC/MS. Overall recoveries ranged from 72 to 118%. Recoveries of mepronil, naproanilide, propanil and flutolanil at fortification levels of 0.1 and 2 mg kg Mn water by this method were 80-112%. The LODs were 0.01 -0.1 pg L ... 

For the determination of five herbicides (ethalfluralin, trifluralin, dinitramine, bu-tralin, and pendimethalin) at fortitication levels between 0.1 and 1 mg soil was extracted with ethyl acetate and the extract was purified on a Florisil column. The residues were eluted with acetone and then analyzed by GC. The average recoveries varied from 75 to 111% for GC/NPD and from 88 to 98% for GC/ITD with the LOD being 0.01 mg kg for both GC/NPD and GC/ITD. The recoveries of pendimethalin at fortification levels ranging from 0.2 to 1 mg kg determined by GC/NPD were between 96 and 101% and the LOD was lower than 0.01 mg kg ... 

In another study, catfish samples were homogenized in ethyl acetate, and the residues were partitioned into acetonitrile and petroleum ether, subjected to C-18 SPE purification, and analyzed using LC/UV detection. "" Quantitative recoveries were obtained for atrazine, simazine, and propazine in the 12.5-100 lagkg concentration range. 

Urine was analyzed for atrazine, DEA, DIA, and DACT at the O.I-IOO agkg concentration range but detailed recovery information was not provided. A 5-mE urine sample was mixed in a tube for 15 min with 5mE of diethyl ether and 0.7 g of sodium chloride. After separation of the layers, the aqueous fraction was mixed with 5 mL of ethyl acetate for a second partitioning step. The two organic fractions... 

The injection standards of carfentrazone-ethyl must be in acetonitrile. Other solvents (e.g., ethyl acetate) lead to poor chromatography following injection of matrix samples. This can lead to apparent enhanced recoveries of analyte in the fortified samples. 

The partition rates of orbencarb and I in aqueous solutions (pH 2-12) into ethyl acetate-n-hexane (1 1, v/v) were as high as 87-90%, and the partition rate did not differ depending on the pH of the liquid. On the other hand, the recovery of II from aqueous solutions into ethyl acetate-n-hexane (1 1, v/v) was 85% at pH 2, 34% at... 

Obana et alP reported a modified ethyl acetate extraction which used a super absorbent polymer instead of sodium sulfate to absorb water. Eollowing cleanup by carbon-based SPE and/or gel permeation chromatography (GPC), recoveries in excess of 70% were achieved for the majority of the 107 pesticides of interest in asparagus, orange, potato and strawberry. The super absorbent polymers are now being incorporated into ASE procedures. 

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