Acetone drying

The acetone used was commercial acetone dried over calcium chloride for a week and then distilled. 

The proper volume of acetylene is measured with a water gasometer as described in Ovg. Synth., Colleat. Vol. 1 1941, 230, with two modifications (a) Two traps immersed in an acetone-dry ice bath at -65°C are placed between the acetylene tank and the gasometer in order to remove acetone. (b) The washing bottles between the gasometer and the reaction flask are replaced by a drying tube (2 x 30-cm column packed with anhydrous CaCl2). 

A Neslab LILT-80 refrigerated circulating bath was used. Alternatively, a Dewar condenser cooled with acetone-dry ice can be used. 

Amino-6-methyIpyridine [1824-81-3] M 108.1, m 44.2 , b 208-209 , pK 7.41. Crystd three times from acetone, dried under vacuum at ca 45 . After leaving in contact with NaOH pellets for 3h, with occasional shaking, it was decanted and fractionally distd [Mod, Magne and Skau J Phys Chem 60 1651 1956]. Also recrystd from CH2CI2 by addition of pet ether. [Marzilli et al. J Am Chem Soc 108 4830 1986.]... 

Dihydroxybenzoic acid [490-79-9] M 154.1, m 204.5-205", pK 2.95. Crystd from hot water or benzene/acetone. Dried in a vacuum desiccator over silica gel. 

Dinitrobiphenyl [1528-74-1] M 244.2, m 240.9-241.8 . Crystd from benzene, EtOH (charcoal) or acetone. Dried under vacuum over P2O5. 

Malonic acid [141-82-2] M 104.1, m 136 , pK 2.58, pKj S.OO. Crystd from benzene/diethyl ether (1 1) containing 5% of pet ether (b 60-80°), washed with diethyl ether, then recrystd from H2O or acetone. Dried under vac over cone H2SO4. 

Nitrophthalic anhydride [641-70-3] M 193.1, m 164 . Crystd from benzene, benzene/pet ether, acetic actic or acetone. Dried at 100°. 

Tetraethylammonium tetraphenylborate [12099-10-4] M 449.4. Recrystd from aqueous acetone. Dried in a vacuum oven at 60° for several days. Similarly for the propyl and butyl homologues. 

Tetramethylammonium iodide [75-58-1] M 201.1, m >230°(dec). Crystd from water or 50% EtOH, EtOH/diethyl ether, ethyl acetate, or from acetone/MeOH (4 1) by adding an equal volume of acetone. Dried in a vacuum desiccator. 

Tetra-n-propylammonium iodide [631-40-3] M 313.3, m >280 (dec). Purified by crystn from EtOH, EtOH/diethyl ether (1 1), EtOH/water or aqueous acetone. Dried at 50° under vacuum. Stored over P2O5 in a vacuum desiccator. 

Sodium poly(a-L-glutamate). It was washed with acetone, dried, dissolved in water and ppted with isopropanol at 5°. Impurities and low molecular weight fractions were removed by dialysis of the aqueous solution for 50h, followed by ultrafiltration through a filter impermeable to polymers of molecular weights greater the 10. The polymer was recovered by freeze-drying. [Mori et al. J Chem Soc, Faraday Trans I 2583 1978.]... 

Tetraphenylphosphonium chloride [2001-45-8] M 314.9, m 273-275". Crystd from acetone. Dried at 70° under vacuum. Also recrystd from a mixture of 1 1 or 1 2 dichloromethane/pet ether, the solvents having been dried over anhydrous K2CO3. The purified salt was dried at room temperature under vasuum for 3 days, and at 170" for a further 3 days. Extremely hygroscopic. 

The reaction is exothermic. Two hours is more than enough time. Too vigorous a reaction can be controlled by an acetone-dry ice bath. 

The propyne (b.p. —23.2°) is precondensed to the mark in a volumetric flask cooled by acetone-dry ice. Evaporation of some propyne during addition will lead to a moderate molar excess of l-bromo-3-chloropropane, regarded as desirable in preventing formation of diyne product. 

B. 3,3-Dimethoxycyclopropene. A 500-ml., three-necked, round-bottomed flask is equipped with a magnetic stirrer, a gas-inlet tube, a thermometer, and an acetone-dry ice condenser charged with acetone-... 

If it is inconvenient to add sulfur tetrafluoride directly from a cylinder, it may first be condensed in a calibrated trap containing a boiling chip and cooled in a acetone-dry ice bath. When cooled to — 78°, 119 g. of sulfur tetrafluoride is about 62 ml. The sulfur tetrafluoride can be added to the cooled flask by allowing it to distil slowly from the trap. 

This reaction is significantly exothermic. Stronger cooling as from an acetone-dry ice bath can he employed if desired to expedite the addition of diol. In any event, a temperature in excess of 20 leads to unwanted rapid hydrolysis and formation of water-soluble byproducts. 

A 1-1., three-necked, round-bottomed fiask is equipped with an efficient dry-ice condenser (Note 1), a mechanical stirrer, and a gas-inlet tube. The fiask is immersed in an acetone-dry ice bath and 600 ml. of anhydrous ammonia is introduced. After replacing the inlet tube with a... 

Apply sample followed by 5% potassium carbon- [16] ate solution in aqueous acetone, dry, apply 50% methyl iodide in acetone. Allow to react for 3 h at 50 °C in an atmosphere of methyl iodide — acetone (1 + 4), dry and develop. Oleanonic acid, for example, yields its methyl ester. 

A suspension of 17a,21-dihydroxypregna-4,9(ll)-diene-3,20-dione 21-acetate (0.77 g) and iV-bromoacetamide (0.3 g) in anhydrous methylene dichloride (40 ml) is added over 2-3 min with stirring to a mixture of anhydrous hydrogen fluoride (10.19 g), and anhydrous tetrahydrofuran (18 g) in a polyethylene bottle at —80° (acetone-dry ice). After 1 hr at —80° the reaction mixture is kept for a further 1 hr at 0° and then added cautiously to an excess of an ice-cold solution of sodium carbonate. Extraction with methylene dichloride and crystallization from acetone-hexane furnish 9a-bromo-ll -fluoro-17a,21-dihydroxypregn-4-ene-3,20-dione 21-acetate (0.69 g), mp 205-208°, raised by several crystallizations from acetone-hexane to 215-217° [aju 142° (CHCI3) max 240-242 mju (e 15,500). 

This section deals with the procedure used by American Polymer Standards Corp. in the manufacture of GPC/SEC gels. The reaction is performed in a three-neck flask equipped with a reflux condenser, a mechanical stirrer, and a thermometer. First, prepare the water phase and then the organic phase. After mixing the organic phase into the water phase, stir at 300 to 400 rpm for 2 hr at 40°C. Heat to 70°C and continue mixing at 150 rpm for 10 hr. Cool to room temperature, (RT), dilute with water, and filter. Wash the gel with water, acetone, toluene, and again with acetone. Dry at 70°C for 12 hr, classify the gel, and package. 

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