Methyl alcohol evaporation rate

B) A 200-g sample of soil was loosely packed in a 24 x 40 cm chromatography colunm and sequentially extracted with redistilled organic solvents at room temperature and a flow rate of 0.5 mL per minute in the following order 200 mL hexane 100 mL hexane + 100 mL methylene chloride 200 mL methylene chloride 100 mL methylene chloride + 100 mL ethyl acetate 200 mL ethyl acetate 100 mL ethyl acetate +100 mL methyl alcohol 200 mL methyl alcohol 100 mL methyl alcohol + 100 mL triply distilled water 800 mL triply distilled water. Each extract was taken to dryness over nitrogen gas except the aqueous one, which was evaporated with a rotary evaporator at 45 °C. Each residue was weighed and bioassayed. 

Generally, solubility of the solid in the liquid is enhanced if the chemicals have similar functional groups [e.g., poly(vinyl alcohol) and water, which contain OH groups] or similar molecular polarity [e.g., poly(vinyl butyral) and ethanol]. Evaporation rate is an important factor in industrial tape casting where the tape is often cast, dried, peeled off from the carrier film, and rolled up for storage in a continuous operation. Fast drying solvents such as toluene and methyl ethyl... 

Among the important oxygenated solvents that are not covered above are furan solvents and organic carbonates. Furan solvents of commercial interest include furfuryl alcohol, tetrahydrofuran, and tetrahydrofurfuryl alcohol. They are characterized by strong solvency for some synthetic polymers. Tetrahydrofuran has an evaporation rate between that of acetone and methyl ethyl ketone. Organic carbonate solvents include ethylene and propylene carbonates, diethyl carbonate and dimethyl carbonate, which are good solvents for many polymers. 

Sodium fluoroacetate.1 To methyl fluoroacetate (46-0 g., 0-5 mol.) suspended in water (100 c.c. containing a few drops of phenolphthalein) sodium hydroxide (0-5 mol., 20 g. in 100 c.c. water) is added slowly. The mixture is kept well stirred, and the rate of addition governed by the disappearance of the red coloration. When the addition of sodium hydroxide is complete, a few more drops of M.F.A. are added to render the solution acid. It is then evaporated on the water-bath until crystallization starts, cooled and the solid filtered off. More solid is obtained from the filtrate by the addition of alcohol total yield 45-5g. (91-0 per cent). (Found F, 19-0. Calc, for C2H202FNa F, 19-0 per cent.) This is characterized as p-nitrobenzyl fluoroacetate as follows. p-Nitrobenzyl bromide (0-9 g.), dissolved in alcohol (10 c.c.), is added to a solution of sodium fluoroacetate (0-3 g.) in the minimum amount of water. The mixture is heated under a reflux condenser for 2 hr. and allowed to cool the solid is collected by filtration, and crystallized from ethanol as long needles, m.p. 76°. 

Amyl, butyl, and iso-propyl acetates are all made from acetic acid and the appropriate alcohols. All are useful lacquer solvents and their slow rate of evaporation (compared to acetone or ethyl acetate) prevents the surface of the drying lacquer from falling below the dew point, which would cause condensation on the film and a mottled surface appearance (blushing). Other esters of importance are used in perfumery and in plasticizers and include methyl salicylate, methyl anthranilate, diethyl-phthalate, dibutyl-phthalate, and di-2-ethylhexyl-phthalate. 

The method of determination by means of the alkyl iodides does not, as a rule, distinguish between ethyl imine and methyl imine in doubtful cases it is necessary to distil a considerable quantity of the hydriodide of the base, and purify and identify the alkyl iodide which is evolved. A second method consists in distilling the base with potassium hydroxide, evaporating the distillate to dryness with hydrochloric acid, separating the organic hydrochlorides from ammonium chloride by means of absolute alcohol and chloroform, and converting the former into pic rates, chloroplatinates, etc., which may then be identified the method must however, be used with caution, as it may lead to errone ous results. 

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