Ethanol, absolute, preparation purification

The 1.5 M solution of dimethylamine in ethanol was prepared as follows Aqueous 40% dimethylamine is heated at 65°C under a flow of argon. The gas is passed through potassium hydroxide pellets and blown across a known quantity (100 mL) of absolute ethanol (analytical grade used without purification), then cooled to 0°C in an ice bath, with continuous stirring, for 3 hr. The ethanolic solution is weighed and diluted to 150 ml with absolute alcohol. The ethanolic dimethylamine solution (ca. 1.5... 

Purification of the Methylamine HCI is in order now, so transfer all of the crude product to a 500mL flask and add either 250mL of absolute Ethanol (see end of FAQ for preparing this) or, ideally, n-Butyl Alcohol (see Footnote 4). Heat at reflux with a Calcium Chloride guard tube for 30 minutes. Allow the undissolved solids to settle (Ammonium Chloride) then decant the clear solution and cool quickly to precipitate out Methylamine HCI. Filter rapidly on the vacuum Buchner funnel and transfer crystals to a dessicator (see Footnote 3). Repeat the reflux-settle-cool-filter process four... 

E. Quench and purification. While the butyllithium addition is taking place, an acidic ethanol quench solution is prepared in a 3-L, two-necked, round-bottomed flask, equipped with a mechanical stirrer and a 250-mL, pressure-equalizing dropping funnel. The flask is charged with 1 L of absolute ethanol and the funnel with 250 mL of acetyl chloride. The ethanol is stirred rapidly and the flask is cooled with an ice bath as the acetyl chloride is added over a 30-40-min period and then the cooling bath is removed and stirring is continued for 20-30 min. After the main reaction mixture has been stirred for 30 min at room temperature, it is cooled with a dry ice-acetone bath. The acidic ethanol solution is cooled with an ice bath and the cold, main reaction mixture is quenched by addition (via a double-ended needle) into the rapidly stirred, cold, acidic ethanol solution over a 3 to 3.5 hr period (Note 16). 

Two sets of 0.01M stock solutions of the benzaldehydes were prepared, one in absolute ethanol and one in DMSO, to be used for the experiments in water-ethanol and water-DMSO mixtures, respectively. Both DMSO (Baker Chemical Co.) and ethanol were used without purification. 

Diethyl oxalate was purchased from Merck and Company, Inc., and was used without further purification. Potassium ethoxide was purchased from Alfa Products, Morton/Thiokol Inc. or preferably was prepared from potassium metal and absolute ethanol. 

To a slurry of 25.9 g (0.0715 mole) of freshly prepared Na3[(Go(003)3] 3H20 in 30 mL of water is added 12.65 g (0.0715 mole) of ethylenediamine-V,A -diacetic acid, and the solution is heated to 50° with stirring for 10 minutes. Ten milliliters of concentrated HCl diluted to 30 mL is added. The solution is filtered and cooled in an ice bath. The product is precipitated by the slow (20 min) addition of 100 mL absolute ethanol to the stirred solution. The dark-purple complex is filtered, washed with 50% aqueous ethanol and ethanol and air-dried. The total yield is 16.4 g (67%). The crude product is used without further purification in the synthesis below. A single recrystallization from ethanol-water gives a pure product. Ana/. Calcd. for Na[CoC6HioN207] I.5H2O C, 24.50 H, 3.82 N, 8.16. Found C, 24.64 H, 3.79 N, 8.17. 

ReOCl3 P(c-C6Hn)3 2 prepared as above (1.5 g, 1.7 mmol) and NaBH4 (1.8 g, 48 mmol) are added to absolute ethanol (100 mL) and the mixture is stirred for 20 h at room temperature. After removal of ethanol in vacuo, the residue is extracted with 4 X 20 mL benzene. The benzene is removed under vacuum and the residue washed with absolute ethanol, giving ReH7 P(c-QH, 1)3)2 as a beige solid in 70% yield. Further purification is achieved by recrystallization from benzene-hexane. 

For washcoat preparation silicalite zeolite powder (S-115 from Union Carbide Corp.) was dried at 100°C in an oven overnight. Prehydrolyzed ethyl-orthosilicate containing 19.52 silica (Silbond H-5 from Stauffer Chemical Co.) was the source of the silica binder. Absolute ethanol (from U.S. Industrial Chemicals Co.) and absolute methanol (reagent grade from J. T. Baker Company) were used without further purification for the liquid portion of the washcoat slurry and for the methanol conversion reaction, respectively. Reagent grade ammonium nitrate (from J. T. Baker) was used for ion-exchange purposes. 

Potassium ethoxide was prepared from 1.95 g potassium and 9.2 mL absolute ethanol in 150 mL anhydrous ether. To this mixture 14.6 g diethyl oxalate was added. After 15 min, a solution of 13.5 g ethyl (3Lmethoxy-2-biphenylyl)-acetate in 50 mL dry ether was added, and the mixture was refluxed for 51 h. The reaction mixture was cooled and extracted with 5% sodium hydroxide solution. The aqueous layer was saturated with carbon dioxide, and the precipitated oil was taken up in ether. Evaporation of the ether solution afforded 10.6 g crude diethyl Q -keto-Q -(3-methoxy-2-biphenylyl)-succinate, which was used in subsequent experiments without purification. From the alkali-insoluble fraction, 4.2 g ethyl (3 -methoxy-2-biphenylyl)-acetate was recovered. 

Synthesis. Dn-Isoleucine is synthesized in about 27% over-all yield by the method of Marvel (554). Diethyl sec.-butylmalonate (A) is prepared in 83% yield from diethyl malonate, sodium, absolute ethanol and sec.-butyl bromide (b.p. 91.3°C.) essentially by the method of Romburgb (673). a-Bromo- S-methylvaleric acid (B) is pr ared in about 67% yield by the alkaline hydrolysis of (A), isolation of sec.-butylmalonic acid ((j), and bromination and decarboxylation of (C). DL-Isoleucine (D), prepared by amination of (B), is recrystallized from 30% ethanol. It has been suggested (39, 485) that the product should be repeated recrystallized from 80% ethanol to free it from allo-isoleucine. It has been found in the writers laboratory that recrystallization from 20% ethanol is an effective purification procedure. The described s thesis is essentially that originated by Brasch and Friedman (125) and Ehrlich (237) and employed by Abd halden and Zeisset (39). 

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