Acetone-methanol

Moderate errors in the total pressure calculations occur for the systems chloroform-ethanol-n-heptane and chloroform-acetone-methanol. Here strong hydrogen bonding between chloroform and alcohol creates unusual deviations from ideality for both alcohol-chloroform systems, the activity coefficients show... 

When there is significant random error in all the variables, as in this example, the maximum-likelihood method can lead to better parameter estimates than those obtained by other methods. When Barker s method was used to estimate the van Laar parameters for the acetone-methanol system from these data, it was estimated that = 0.960 and A j = 0.633, compared with A 2 0.857 and A2- = 0.681 using the method of maximum likelihood. Barker s method uses only the P-T-x data and assumes that the T and x measurements are error free. 

For the acetone-methanol data of Othmer, the correlation coefficient is -0.678, indicating a moderate degree of correlation between the two van Laar parameters. The elongated confidence ellipses shown in Figure 2 further emphasize this correlation. 

Science dealerships aren t the only places to get the stuff one needs. At those mega hardware stores one can find pure acetone, methanol, ethanol, toluene, methyl ethyl ketone, DCM(as a constituent of some stripping agents), sodium hydroxide in the form of lye, and some acids such as sulfuric and hydrochloric. These precious tools can be bought there cheaply and in great quantity. 

Fiaal purification of propylene oxide is accompHshed by a series of conventional and extractive distillations. Impurities ia the cmde product iaclude water, methyl formate, acetone, methanol, formaldehyde, acetaldehyde, propionaldehyde, and some heavier hydrocarbons. Conventional distillation ia one or two columns separates some of the lower boiling components overhead, while taking some of the higher boilers out the bottom of the column. The reduced level of impurities are then extractively distilled ia one or more columns to provide a purified propylene oxide product. The solvent used for extractive distillation is distilled ia a conventional column to remove the impurities and then recycled (155,156). A variety of extractive solvents have been demonstrated to be effective ia purifyiag propylene oxide, as shown ia Table 4. 

Fig. 7. Extractive distillation column profiles for the acetone—methanol—water separation (40). (a) Liquid composition versus theoretical tray location where...

Acetone-methanol Minimum-hoiling azeotrope Water, aniline, ethylene glycol ... 

FIG. 13-72 Effect of solvent concentration on activity coefficients for acetone-methanol system, (a) water solvent, (h) MIPK solvent. 

FIG. 13-73 Residue curve maps for acetone-methanol systems, (a) With water, (h) With MIPK. 

FIG. 13-74 Extractive distillation cohunn composition profile for the separation of acetone-methanol with water. 

FIG. 13-75 Number of theoretical stages versus solvent-to-feed ratio for extractive distillation, a) Close-boiling vinyl acetate-etbyl acetate system with phenol solvent, (h) A2eotropic acetone-methanol system with water solvent. 

Methanol and acetone boil at 64.5°C and 56.1°C, respec tively and form a minimum-boihng azeotrope at 55.3°C. The natural volatility of the system is acetone > methanol, so the favored solvents most likely will be those that cause the acetone to be recovered in the distillate. However, for the purposes of the example, a solvent that reverses the natural volatility vi l also be identified. First, examining the polarity of... 

For materials with very low melting points it is sometimes convenient to use dilute solutions in acetone, methanol, pentane, diethyl ether or CHCI3-CCI4. The solutions are cooled to -78° in a dry-ice/acetone bath, to give a slurry which is filtered off through a precooled Buchner funnel. Experimental details, as applied to the purification of nitromethane, are given by Parrett and Sun [J Chem Educ 54 448 7977]. 

A solution of cholest-4-en-3-one (139), 1 g, in diethylene glycol dimethyl ether (20 ml) is treated for 1 hr with a large excess of diborane at room temperature under nitrogen and then left for a further 40 min. Acetic anhydride (10 ml) is added and the solution refluxed for 1 hr. The mixture is concentrated to a small volume, diluted with water and extracted with ether. The extracts are washed with 10% sodium hydroxide solution, then with water and dried over sodium sulfate. Removal of the solvent leaves a brown oil (1.06 g) which is purified by chromatography on alumina (activity I). Hexane elutes the title compound (141), 0.68 g mp 76-77°. Successive crystallization from acetone-methanol yields material mp 78-79°, [a]p 66°. 

Bisethylenedioxypregn-5-ene. Method A. A mixture of progesterone (10 g), freshly distilled ethylene glycol (80 ml) and benzene (350 ml) is slowly distilled for 15 min to remove traces of water. p-Toluenesulfonic acid monohydrate (0.3 g) is added and the mixture is heated under reflux with stirring for 5 hr with a water separator. Saturated sodium bicarbonate solution is added to the cooled mixture and the benzene layer is separated. The organic layer is washed twice with water, dried and evaporated in vacuo. The residue is crystallized twice from acetone-methanol to give 4.15 g (32%) of bisketal, mp 178-181°. 

Methoxypregna-3,5-dien-20-oned A solution of progesterone (0.3 g) dissolved in 5 ml of 2,2-dimethoxypropane-dimethylformamide (1 1) is treated with p-toluenesulfonic acid monohydrate (8 mg) and 0.1 ml of methanol and then heated under reflux for 3.5 hr. The cooled solution is neutralized with 45 mg of sodium bicarbonate, dissolved in 200 ml of ice water, stirred for 0.5 hr and filtered. The enol ether thus obtained (0.29 g, 92%) is purified by crystallization from acetone-methanol containing a trace of pyridine mp 135-160° [a]o —61° (CHCI3). 

The Nenitzescu process is presumed to involve an internal oxidation-reduction sequence. Since electron transfer processes, characterized by deep burgundy colored reaction mixtures, may be an important mechanistic aspect, the outcome should be sensitive to the reaction medium. Many solvents have been employed in the Nenitzescu reaction including acetone, methanol, ethanol, benzene, methylene chloride, chloroform, and ethylene chloride however, acetic acid and nitromethane are the most effective solvents for the process. The utility of acetic acid is likely the result of its ability to isomerize the olefinic intermediate (9) to the isomeric (10) capable of providing 5-hydroxyindole derivatives. The reaction of benzoquinone 4 with ethyl 3-aminocinnamate 35 illustrates this effect. ... 

Twenty grams of the resulting oily substances were mixed with 20 grams of silicic acid (Mal-linckrodt Chemical Co.),applied to a column 40 cm in length and 4.5 cm in diameter filled with silicic acid,and eluted with a be nzene-ecetone-methanol mixture. The initial eluate which eluted with a 1 1 0 mixture was discarded and the active fractions eluted with 1 3 0 and 1 3 0.3 mixtures were collected and concentrated to dryness in vacuo. 11 g of this crude substance was then dissolved in a small amount of ethyl acetate and applied to the same silicic acid column as above. After discarding the initial eluates by the 1 1 and 2 1 benzene-acetone mixtures, aclacinomycin 8 fractions were first eluted with the above mixtures of 1 3 and 1 5 ratio, and aclacinomycin A fractions were then eluted with the 1 5 0.5 and 1 5 1 benzene-acetone-methanol mixtures. The eluates were dried over anhydrous sodium sulfate and concentrated to dryness in vacuo. 4,8 g of crude aclacinomycin A and 3.5 g of aclacinomycin 8 were obtained as yellow powder. 

Polar organic solvents readily precipitate exopolysaccharides from solution. The solvents commonly used are acetone, methanol, ethanol and propan-2-ol. Cation concentration of the fermentation liquor influences the amount of solvent required for efficient product recovery. In the case of propan-2-ol, increasing the cation concentration can lead to a four-fold reduction in die volume of solvent required to precipitate xanthan gum. Salts such as calcium nitrate and potassium chloride are added to fermentation broths for this purpose. 

Further evidence for neighboring sulfur involvement and ion 208b in the solvolysis of 207 comes from the investigation of the stereochemistry of the products and the observed rearrangements (181). Solvolysis of ester 211 in 4 1 acetone methanol at 25° gave only one geometric isomer, 212, as product. 

In a 100 mL round-bottomed flask coimected to a reflux condenser, 4.88 g (20 mmol) uridine 1 is suspended and stirred in 12.44 mL (60 mmol) HMDS 2, 4.15 mL (50 mmol) pyrrolidine, 0.1 mL Me3SiCl 14, and 15 mL abs. pyridine. After 4.5 h heating in an oil bath at 140-145 °C the reaction mixture turns yellowish and is complete according to TLC (acetone-methanol, 3 1). After evaporation of the solvents in vacuo, the yellowish, partly crystalline residue of crude 5 b is boiled for 3 h in 100 mL methanol and then kept at room temperature for 16 h. After evaporation of the solvent, 6.09 g crade 4-pyrrohdino-l-(79-D-ribofuranosyl)-l,2-dihydropyrimidine-2-one 6b is obtained. This is recrystallized from 90 mL boiling methanol and subsequently from 30 mL methanol to give, in two crops, 5.677 g (95.4%) pure 6b, m.p. 211-213°C [11]. 

To obtain anthocyanins closer to their natural state, a number of researchers have used neutral solvents for initial extraction such as 60% methanol, n-butanol, cold acetone, mixtures of acetone, methanol, and water, or simply water. Methanol is the most common solvent used for anthocyanin extraction. Metivier et al. (1980) compared the efficiency of extraction with three different solvents (methanol, ethanol, and water) and different acids, and found that methanol extraction was 20% more effective than ethanol and 73% more effective than water when used for anthocyanin recovery from grape pomace. 

Chlorine-enhancement may offer a partial solution. The addition of the chlorinated olefin TCE, PCE, or TCP to air/contaminant mixtures has recently been demonstrated to increase quantum yields substantially [1, 2, 6]. We recently have extended this achievement [3], to demonstrate TCE-driven high quantmn efficiency conversions at a reference feed concentration of 50 mg contaminant/m air not only for toluene but also for other aromatics such as ethylbenzene and m-xylene, as well as the volatile oxygenates 2-butanone, acetaldehyde, butsraldehyde, 1-butanol, methyl acrylate, methyl-ter-butyl-ether (MTBE), 1,4 dioxane, and an alkane, hexane. Not 1 prospective contaminants respond positively to TCE addition a conventional, mutual competitive inhibition was observed for acetone, methanol, methylene chloride, chloroform, and 1,1,1 trichloroethane, and the benzene rate was altogether unaffected. 

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