Methyl acetate-methanol-calcium

The author selected the system containing salt which is not dissolved with other components but only with a particular component of a solvent mixture as a system with which the phenomenon of preferential solvate can be understood easily. Calcium chloride is dissolved with alcohol but it is not dissolved well with ester. Thus, calcium chloride forms a preferential solvate with alcohol and does not with ester. For the component system which consists of calcium chloride, alcohol, and ester, the author selected the following three systems for which vapor-liquid equibrium relations have been measured methanol-ethyl acetate-calcium chloride (I) methyl acetate-methanol-calcium chloride (3) and n-butyl acetate-n-butanol-calcium chloride (3). 

Figure 5. Preferential solvation number in the methyl acetate-methanol-calcium chloride system at 1 atm (O), CaCl2 6 tot % (A), CaCl2 15 wt % (0), CaCl2 saturated (5).

Figure 2. Solubility of calcium chloride in boiling methyl acetate-methanol...

Figures 7, 8, and 9 indicate the prediction results for the following three systems methanol-ethyl acetate, methyl acetate-methanol, and butyl acetate-butanol with saturated calcium chloride, respectively. The absolute value of mean errors At/ were 0.018 and 0.014 for each system, while the maximum and minimum errors were 0.047 and 0, 0.039 and 0.005, and 0.039 and 0.005, respectively.

The preferential solvation formed between salt and solvent molecules causes a salt effect on vapor-liquid equilibria. A method of prediction of salt effect based on the preferential solvation number was reported previously for the case in which salt was solved below the saturation level. The idea introduced in this chapter applies for salt solved in saturation. The alcohol-ester-calcium chloride system for which the preferential solvation was thought to be formed was examined. Specifically, calcium chloride dissolves readily in alcohol but only sparingly in ester. Thus, when calcium chloride is solved into alcohol-ester mixed solvent, the calcium chloride will form a preferential solvation with alcohol only. Methanol-methyl acetate, butanolr-butyl acetate, and methanol-ethyl acetate systems were selected for the mixed-solvent systems. 

Parkesine). Nitrocellulose is mixed with wood naphtha (a mixture of methanol, acetone, acetic acid, and methyl acetate formed during the distillation of wood) to produce a malleable solid. It is marketed, with little success, as a sculpting material. German chemist Eriedrich Wohler first makes calcium carbide, from which he later obtains acetylene. 

Methyl a-D-glucopyranoside (7.6 g), in dry pyridine (lOOmL) and benzyl chloride (7.6 g), was refluxed with a calcium chloride tube fitted to the top of the condenser for 9 h. After cooling to room temperature, acetic anhydride (20 mL) was added, and the solution allowed to stand overnight Excess water was added, and the mixture was extracted with benzene. The benzene layer was washed with, in turn, ice cold 1 M sulfuric acid, saturated aqueous sodium bicarbonate, and finally water. The benzene solution was dried over magnesium sulfate, filtered and concentrated. The dark-colored residue was recrystallized to yield methyl 2,3-di-0-acetyl-4,5-0-benzylidene-a-D-glucopyranoside 21 mp 101-104°C, [a]D +75° (c 1.0, chloroform). Part of die material was deacetylaied with 1.67% ammonia in methanol to yield methyl 4,6-0-benzylidene-a-D-glucopyranoside 19 mp 161-163°C undepressed on admixture with an authentic sample. 

Aromatic aldehydes (10 mmol) and trimethylorthoformate (20 mmol) was added to a mixture of sulfonamide (10 mmol), finely powdered calcium carbonate (9 g) and K-10 clay (2 g). The solid homogenized mixture was placed in a modified reaction tube which was connected to a removable cold finger and sample collector to trap the ensuing methanol and methyl formate. The reaction tube is inserted into Maxidigest MX 350 (Prolabo) microwave reactor equipped with a rotational mixing system. After irradiation for a specified period, the contents were cooled to room temperature and mixed thoroughly with ethyl acetate (2 x 20 mL). The solid inorganic material was filtered off and solvent was evaporated to afford tlie residue which was crystallized from the mixture of hexane and ethyl acetate. 

Dimethylaniline has been prepared by reduction of the corresponding nitro compound, either chemically or catalyti-cally. It has been prepared from 3,4-dimethylphenol by heating with ammonia, ammonium bromide, and zinc bromide from w-toluidine hydrochloride by alkylation with methanol at high temperatures from anhydro-4-amino-2-methylbenzyl alcohol by dry distillation from calcium hydroxide from 2-methyl-S-aminobenzyl alcohol by reduction with sodium from 2-methyl-5-nitrobenzyl chloride and 2-methyl-S-nitrobenzyl acetate by catalytic reduction from o-xylene by direct amination with hy-droxylamine hydrochloride in the presence of aluminum chloride and from 3,4-dimethylacetophenone by the Beckmann rearrangement of the oxime.i" The present method has been published. ... 

Table IV also includes some values determined in methanol as the solvent these are very much higher (and, hence, also more accurate) than those in water, because the polyol competes with methanol, rather than with water, for outer-sphere positions on the cation. These figures explain why carbohydrates are soluble in methanol or ethanol containing high concentrations of calcium chloride, or even potassium acetate, and in such systems as lithium chloride in 2-methoxyethanol. ° Sugar derivatives that are soluble in non-hydroxylic solvents form complexes with cations in those solvents even more readily for example, methyl 2,3-0-isopropylidene-4-0-methyl-) -L-rhamnopyranoside (24) (but not its a anomer) will form a complex with sodium iodide in acetone, the Na" " ion coordinating to 0-1,0-2, and 0-3. In aqueous solution, the concentration of this complex would be negligible.

Mixed calcium-magnesium salt. Colorless crystalline lid, mp 270-250° (dec), uv max (ethanol, neutral) 202, 29,303. 370 nm (E 425, 490, 278, 109). Insol in water, fauns, hexane, heptane. Very slightly sol in methanol, DMSO. Very sol in methylene chloride, chloroform, acetone methyl ethyl ketnne, diethyl ketone, ethyl acetate. 

In continuation of studies on the aromatisation of synthetic polyketides, aryl C-glycosides in the 1,8-dihydroxynaphthalene series were obtained by an approach modelled on biomimetic lines. Thus diethyl 3-hydroxyglutarate (obtained from L-rhamnal) in tetrahydrofuran was added at O C under nitrogen to the lithium-sodium dianion of methyl acetoacetate (15 moles) in tetrahydrofuran/hexamethyl phosphoric triamide (1 1), the mixture was stirred at ambient temperature for 2.5 hours and after acidification the recovered crude diethyl 3,5,9,11-tetraoxo-tridecanedioate was refluxed for 2.5 hours in methanolic solution containing calcium acetate to afford the product shown in 40% yield as a single isomer, after 0-acylation, purification and O-deacylation (ref.61). ( MOM = methoxymethyl)... 

Monosilicic acid can be prepared from the silicate-acid system, just as from the silicon tetrachloride-water or methyl orthosilicate-water systems [746]. Acetic acid or resin exchangers in the H-form can be added to dilute solutions of sodium silicate. Monosilicic acid is formed by reaction of solid calcium orthosilicate with hydrogen chloride in methanol, according to the equation ... 

Resorcinol and its mono- and diacetates can be separated from one another and from hexachlorophene by TLC after extraction from dermatological preparations silica gel layers were used, prepared with 0.01 M aqueous sodium tungstate as complexing agent, benzene-dioxan-acetic acid (90 +10 + 2) as solvent and ferricyanide-ferric chloride (Rgt. No. Ill) for detection [64]. Hexyhesorcinol and hexachlorophene can be separated on silica gel G layers, using methyl isobutyl ketone [64]. A separation of dichlorophene and hexachlorophene has been possible with n-heptane,saturated with acetic acid,and layers of a hand prepared mixture of silica gel and starch binder [26]. Some of the components of tar oils and their TLC are also of pharmaceutical interest [130]. TLC-data for dithranol have also been described [15]. lodo-chlorhydroxyquin(5-chloro-8-hydroxy-7-iodoquinoline) has been separated from possible contaminants originating from its synthesis, by TLC in methanol on polyamide-calcium sulphate layers (5g polyamide + 3.5 g calcium srdphate + 10 ml water) [90]. 

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