Chloroform removal

To obtain crystalline perbenzoic acid, dry the moist chloroform solution with a little anhydrous sodium or magnesium sulphate for an hour, filter, and wash the desiccant with a little dry chloroform. Remove the chloroform under reduced pressure at the ordinary temperature whilst carbon dioxide is introduced through a capillary tube. Dry the white or pale yellow residue for several hours at 30-35° under 10 mm. pressure. The yield of crystalline perbenzoic acid, m.p. about 42°, which is contaminated with a little benzoic acid, is 22 g. It is moderately stable when kept in the dark in a cold place it is very soluble in chloroform, ethyl acetate and ether, but only shghtly soluble in cold water and in cold hght petroleum. 

Concentration of organic contaminants can affect the adsorption process. A given AC filter may be more effective than another type of AC filter at low contaminant concentrations, but may be less effective than the other filter at high concentrations. This type of behavior has been observed with chloroform removal. The filter manufacturer should be consulted to determine how the filter will perform for specific chemicals at different levels of contamination. 

The ethyl p-chlorophenoxyisobutyrate may be obtained by heating a mixture of 206 parts of dry p-chlorophenoxyisobutyric acid, 1,000 parts of ethanol and 40 parts of concentrated sulfuric acid under reflux during 5 hours. The aicohol is then distilled off and the residue is diluted with water and extracted with chioroform. The chloroform extract is washed with sodium hydrogen carbonate solution, dried over sodium sulfate and the chloroform removed by distillation. The residue is distilled under reduced pressure and there is obtained ethyl p-chlorophenoxyisobutyrate, BP 148° to 150°C/20 mm. 

A mixture of 49 g of this ester compound, 76 g of 9B% formic acid and 6B ml of formalin solution is heated under reflux for B hours. The solvents are then removed in vacuo on the steam bath, the residue dissolved in water, made alkaline with ammonium hydroxide and extracted with chloroform. Removal of the solvent and distillation in vacuo yieids ethyl 4-di-methylaminocyclohexylcarboxylate, boiling point 122°C to 125°C/10 mm. 

Based upon a vapor pressure of 159 mm Hg at 20 °C, chloroform is expected to exist almost entirely in the vapor phase in the atmosphere (Boublik et al. 1984 Eisenreich et al. 1981). Large amounts of chloroform in the atmosphere may be removed by wet deposition since chloroform has significant solubility in water. This is confirmed by its detection in rainwater (Kawamura and Kaplan 1983). Most of the chloroform removed in precipitation, however, is likely to reenter the atmosphere by volatilization. Trace amounts of... 

The solution is filtered to remove any resinous material, then saturated with ammonium sulfate and extracted with five 80-cc. portions of chloroform (Note 5). The chloroform solution is dried with 20 g. of anhydrous sodium or magnesium sulfate, filtered, and the chloroform removed by evaporation on a steam bath... 

B.P.), the mixture being cooled in ice and salt. After 30 minutes the copper chloride is filtered off and the chloroform removed from the filtrate by a current of air, 17 grams (78 per cent, yield) of pure selenium acetylacetone remaining.1... 

Nitromethane 2a (1.2 mmol), alumina (1 g, basic activated at 200 °C) and benzal-acetophenone 1 (1.2 mmol) were mixed together without solvent in an Erlen-meyer flask and placed in a commercial microwave oven (operating at 2450 Hz frequency) and irradiated for 18 min. The reaction mixture was allowed to reach room temperature and extracted with chloroform. Removal of solvent and the re-... 

To obtain crystalline perbenzoic acid the following procedure may be adopted, the operation being conducted behind a shatter-proof screen. Dry the moist chloroform solution with a little sodium sulphate or magnesium sulphate for an hour, filter and wash the desiccant with a little dry chloroform. Remove... 

Note. (1) Triphenylphosphine may be removed from a mixture of triphenylphosphine and organic compounds by stirring a chloroform solution over copper(i) chloride, the reaction mixture is filtered, the chloroform removed and the organic compound dissolved in ether or methanol. A 1 1 Ph3P CuCl complex is formed which is soluble in chloroform but insoluble in ether or methanol. 

Chloroform removal was found to be dependent on the water quality. In potable water, at two solute concentrations of 75 and 750 pg/L, 99% removal was observed at 800 krads (Cooper et al., 1993a). With the similar initial concentrations and irradiation doses in secondary and raw waste-waters, the removal efficiency was 85 and 90%, respectively. However, for... 

The dibromo compound is dehalogenated by agitating under a hydrogen atmosphere a mixture of 80 g. (0.23 mole) of the dibromo compound, 700 ml. of N aqueous sodium hydroxide solution, and a catalyst consisting of 2% palladium on polyvinyl alcohol prepared from 0.5 g. of palladium chloride (p. 244). To the resulting mixture is added 120 g. of sodium chloride, and the precipitated catalyst is removed by filtration. The filtrate is acidified and extracted with chloroform. Removal of the chloroform by distillation gives 35 g. (80%) of ethyl orcinol-6-carboxylate, m.p. 132-133°. 

Extract DNA with phenol chloroform. Remove aqueous phase (avoid interface) and add to 1 mL ethanol. Samples can be stored overnight at -20°C at this stage, if necessary. 

Vinyl Pentachlorophenyl Ether, (9). Method A 2-Pentachlo-phenoxyethyl bromide (0.4 g, 1.1 mmol) was dissolved In tetrahydrofuran (3 ml) and l,5-dlazablcyclo-5,4,0-undec-5-ene (DBU) (0.16 g, 1.1 mmol) was added dropwlse to the solution. The mixture was refluxed for 30 minutes and water (100 ml) was added, and the solution was extracted with chloroform. The chloroform extract was dried with anhydrous MgS04 and the chloroform removed In vacuo to yield 0.2 g (64.5%) of (9). 

Sample preparation Plasma. 1 mL Plasma -i- 2 mL 100 mM pH 6.0 phosphate buffer + 500 pL 0.5% N-(4-benzoylphenyl)maleimide in acetone, vortex for 15 s, let stand at room temperature for 10 min, add 2 mL 500 mM pH 7.0 phosphate buffer, add 100 pL 40 pg/mL ISl in acetone, wash twice with 4 mL portions of ether, acidify the aqueous phase with 500 pL 6 M HCl, extract with 7 mL chloroform. Remove the organic layer and evaporate it to dryness, reconstitute the residue in 100 pL MeOH, iiyect a 20 pL aliquot. Urine. 200 pL Urine + 200 pL 0.5% N-(4-benzoylphenyl)maleimide in acetone -I- 200 pL 100 mM pH 6.5 phosphate buffer, mix, let stand at room temperature for 15 min, add 2.5 mL 500 mM pH 7.0 phosphate buffer, wash with 4 mL diethyl ether, add 100 pL 10 pg/mL IS2 in acetone to the aqueous phase, acidify with 500 pL 6 M HCl, extract with 6 mL chloroform. Remove the organic layer and evaporate it to dryness, reconstitute the residue in 200 pL MeCN, inject a 20 pL aliquot. (Prepare N-(4-benzoylphenyl)maleimide by adding 5.3 g maleic anhydride to 9.6 g 4-aminobenzophenone in dioxane (Caution Dioxane is a carcinogen ), stir at room temperature (Japan Pat. 59,204,171 (19 Nov. 1984) Chem. Abstr. 1985, 102, 113288t).)... 

Repeat Example 4.5 using the same airflow rate used in Problem 4.15, and specifying a chloroform removal efficiency of 99%. 

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