Ketone extraction, methyl-isobutyl

Liquid-liquid extractions using ammonium pyrrolidine dithiocarbamate (APDC) as a metal chelating agent are commonly encountered in the analysis of metal ions in aqueous samples. The sample and APDC are mixed together, and the resulting metal-ligand complexes are extracted into methyl isobutyl ketone before analysis. 

Aqueous solutions buffered to a pH of 5.2 and containing known total concentrations of Zn + are prepared. A solution containing ammonium pyrrolidinecarbodithioate (APCD) is added along with methyl isobutyl ketone (MIBK). The mixture is shaken briefly and then placed on a rotary shaker table for 30 min. At the end of the extraction period the aqueous and organic phases are separated and the concentration of zinc in the aqueous layer determined by atomic absorption. The concentration of zinc in the organic phase is determined by difference and the equilibrium constant for the extraction calculated. 

Ketones are an important class of industrial chemicals that have found widespread use as solvents and chemical intermediates. Acetone (qv) is the simplest and most important ketone and finds ubiquitous use as a solvent. Higher members of the aUphatic methyl ketone series (eg, methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone) are also industrially significant solvents. Cyclohexanone is the most important cycHc ketone and is primarily used in the manufacture of y-caprolactam for nylon-6 (see Cyclohexanoland cyclohexanone). Other ketones find appHcation in fields as diverse as fragrance formulation and metals extraction. Although the industrially important ketones are reviewed herein, the laboratory preparation of ketones is covered elsewhere (1). 

Solvent Treatment. Solvent processes can be divided into two main categories, solvent extraction and solvent dewaxing. The solvent used in the extraction processes include propane and cresyHc acid, 2,2 -dichlorodiethyl ether, phenol (qv), furfural, sulfur dioxide, benzene, and nitrobenzene. In the dewaxing process (28), the principal solvents are benzene, methyl ethyl ketone, methyl isobutyl ketone, propane, petroleum naphtha, ethylene dichloride, methylene chloride, sulfur dioxide, and iV-methylpyrroHdinone. 

The raw precious metal concentrate is totally dissolved in hydrochloric acid—chlorine solution to form the soluble chloride ions of each of the metals. Silver remains as insoluble silver chloride and can be filtered off. Gold, in the form of [AuClJ, is extracted with, eg, tributyl phosphite or methyl isobutyl ketone. Base metals are also extracted in this step, and are removed from the organic phase by scmbbing with dilute hydrochloric acid (HCl). Iron powder is then used to reduce the gold species and recover them from the organic phase. 

There are a number of minerals in which thorium is found. Thus a number of basic process flow sheets exist for the recovery of thorium from ores (10). The extraction of mona ite from sands is accompHshed via the digestion of sand using hot base, which converts the oxide to the hydroxide form. The hydroxide is then dissolved in hydrochloric acid and the pH adjusted to between 5 and 6, affording the separation of thorium from the less acidic lanthanides. Thorium hydroxide is dissolved in nitric acid and extracted using methyl isobutyl ketone or tributyl phosphate in kerosene to yield Th(N02)4,... 

In the initial thiocyanate-complex Hquid—Hquid extraction process (42,43), the thiocyanate complexes of hafnium and zirconium were extracted with ether from a dilute sulfuric acid solution of zirconium and hafnium to obtain hafnium. This process was modified in 1949—1950 by an Oak Ridge team and is stiH used in the United States. A solution of thiocyanic acid in methyl isobutyl ketone (MIBK) is used to extract hafnium preferentially from a concentrated zirconium—hafnium oxide chloride solution which also contains thiocyanic acid. The separated metals are recovered by precipitation as basic zirconium sulfate and hydrous hafnium oxide, respectively, and calcined to the oxide (44,45). This process is used by Teledyne Wah Chang Albany Corporation and Western Zirconium Division of Westinghouse, and was used by Carbomndum Metals Company, Reactive Metals Inc., AMAX Specialty Metals, Toyo Zirconium in Japan, and Pechiney Ugine Kuhlmann in France. 

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-... 

FIG. 15-42 Extraction in Mixco columns, methyl isobutyl ketone-acetic acid-water (continuous), d, = 0.5 ft, Zj = 0..3.3.3 ft, X = flooded condition. To convert feet to meters, multiply by 0..34S to convert feet per hour to meters per hour, multiply by 0.3048. 

Typical data for operation with methyl isobutyl ketone, water, acetic acid four stages 101.6-mm stage height, 152-mm-diameter column extraction, water ketone. 

FIG. 15 53 Effect of pulsing on extraction in a packed column methyl isobutyl ketone-acetic acid-water (continuous). Tower diameter = 1.58 in, 27-in depth of V4-in Raschig rings. = Vc = 7.5 to 10. To convert inches to centimeters, multiply by 2.54. [Data of Chanhy, von Berg, and Wiegandt, Ind. Eng. Chem., 47, 1153 (1.9.55), with permission. ... 

Procedure has been proposed for the P(V) and As(V) determination based on the selective extraction of ionic associate of Crystal Violet with reduced molybdophosphate with mixture of inert (toluene) and active (methyl isobutyl ketone) solvents. Extraction of reagent is negligible. After concentration determination lower than 10 mol/1 of P(V) and As(V) is possible. 

A selected strain o1 Streptomyces halstedii was cultivated in an aqueous nutrient medium under aerobic conditions and the resulting broth containing carbomycin antibiotics was filtered. The solutions was extracted twice at pH 6.5 with one-quarter volume of methyl isobutyl ketone. The combined extracts were concentrated to one-tenth volume under vacuum, and the antibiotics were extracted into water adjusted to a pH of about 2 with sulfuric acid. After adjusting the separated aqueous solution to pH 6.5, the antibiotic was extracted into benzene and the solution was concentrated to a small volume. Addition of hexane resulted in the separation of a solid product containing the benzene complexes of carbomycin A and carbomycin B, present in the fermentation broth. 

The course of the fermentation is tested by removal of samples, which are extracted with methyl isobutyl ketone. The extract is analyzed by paper chromatography in a system of dioxane toluene/propylene glycol. 

After the end of the fermentation (28 hours) the culture broth is filtered off by suction over a large suction filter. The mycel residue is washed with water several times. The filtrate is extracted three times, each time with 10 liters of methyl isobutyl ketone. The extract is concentrated under vacuum in a circulating evaporator and in a round flask carefully dried under vacuum. The residue is crystallized from acetone/isopropyl ether. The melting point is 157°-158°C (fermentation yield = 60%). The pure product yield obtained after a second crystallization and chromatography of the mother liquor on silica gel amounts to 53% of the theoretical. 

The solution is then extracted with 5 ml xylene. The aqueous layer is layered with 5 ml methyl isobutyl ketone and the pH adjusted to 5.0 with 1 N NaOH and chilled overnight. The resulting crystals are filtered off, washed with water and air dried. Yield, 272 mg (44%), decomposes at 202°C. 

Discussion. Because of the specific nature of atomic absorption spectroscopy (AAS) as a measuring technique, non-selective reagents such as ammonium pyrollidine dithiocarbamate (APDC) may be used for the liquid-liquid extraction of metal ions. Complexes formed with APDC are soluble in a number of ketones such as methyl isobutyl ketone which is a recommended solvent for use in atomic absorption and allows a concentration factor of ten times. The experiment described illustrates the use of APDC as a general extracting reagent for heavy metal ions. 

Transfer the solution to a 250 mL separatory funnel, rinsing out the beaker with a little water. Add 5 mL of the 2 per cent NaDDC reagent and allow to stand for one minute, and then add a lOmL portion of 4-methylpentan-2-one (methyl isobutyl ketone), shake for one minute and then separate and collect the organic layer. Return the aqueous phase to the funnel, extract with a further lOmL portion of methyl isobutyl ketone, separate and combine the organic layer with that already collected. Finally, rinse the funnel with a little fresh ketone and add this rinse liquid to the organic extract. In these operations the lead is converted into a chelate which is extracted into the organic solvent. 

Note. If lead caprate is not available, standard lead solutions can be prepared from aqueous solutions containing known weights of lead nitrate and following through the extraction procedure as detailed for the final extraction of lead into methyl isobutyl ketone for the alloy. It should also be noted that steps should be taken to avoid excessive inhalation of the vapour of the methyl isobutyl ketone, which can cause a headache. 

Similarly to quantitative determination of high surfactant concentrations, many alternative methods have been proposed for the quantitative determination of low surfactant concentrations. Tsuji et al. [270] developed a potentio-metric method for the microdetermination of anionic surfactants that was applied to the analysis of 5-100 ppm of sodium dodecyl sulfate and 1-10 ppm of sodium dodecyl ether (2.9 EO) sulfate. This method is based on the inhibitory effect of anionic surfactants on the enzyme system cholinesterase-butyryl-thiocholine iodide. A constant current is applied across two platinum plate electrodes immersed in a solution containing butyrylthiocholine and surfactant. Since cholinesterase produces enzymatic hydrolysis of the substrate, the decrease in the initial velocity of the hydrolysis caused by the surfactant corresponds to its concentration. Amounts up to 60 pg of alcohol sulfate can be spectrometrically determined with acridine orange by extraction of the ion pair with a mixture 3 1 (v/v) of benzene/methyl isobutyl ketone [271]. 

In 1961, Roig and Dodson carried out a further study of the exchange in perchlorate media under identical conditions (25 °C, fi = 3.0 M) to those in the Tl(III) hydrolysis studyThe isotope was used, with a separation procedure based on extracting TI(III) from reaction mixtures with either methyl isobutyl ketone or diethyl ether. The exchange was examined in the absence of light, and a correction procedure to eliminate the catalytic effects of traces of chloride ions was used since Tl(III) concentrations of 10 M were necessary at the very low acidities employed. Using the known values of the first and second hydrolysis constants of Tl(III) (K2 and K3)... 

Metals were extracted with isobutyl methyl ketone + amyl acetate (2 1) and chromatographed on cellulose layer... 

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