Methanol water removal

RCH=N—ONa and R R C=N—ONa) which may be filtered off and washed with methanol to remove traces of sodium methoxide. It should be kept moist with methanol the sodium derivative, if allowed to dry, may become very explosive. Also, upon contact with a trace of water, it is liable to decompose with explosive violence. The sodium derivative may be dissolved by successively adding small quantities to cold water with continual stirring. 

Starting with DMT, methanol is removed from the reaction starting with TA, water is removed. Catalysts ate used to transesterrfy DMT but not for direct esterification of TA. The second step is the polycondensation reaction which is driven by removing glycol. A polycondensation catalyst is used. 

The crude ketal from the Birch reduction is dissolved in a mixture of 700 ml ethyl acetate, 1260 ml absolute ethanol and 31.5 ml water. To this solution is added 198 ml of 0.01 Mp-toluenesulfonic acid in absolute ethanol. (Methanol cannot be substituted for the ethanol nor can denatured ethanol containing methanol be used. In the presence of methanol, the diethyl ketal forms the mixed methyl ethyl ketal at C-17 and this mixed ketal hydrolyzes at a much slower rate than does the diethyl ketal.) The mixture is stirred at room temperature under nitrogen for 10 min and 56 ml of 10% potassium bicarbonate solution is added to neutralize the toluenesulfonic acid. The organic solvents are removed in a rotary vacuum evaporator and water is added as the organic solvents distill. When all of the organic solvents have been distilled, the granular precipitate of 1,4-dihydroestrone 3- methyl ether is collected on a filter and washed well with cold water. The solid is sucked dry and is dissolved in 800 ml of methyl ethyl ketone. To this solution is added 1600 ml of 1 1 methanol-water mixture and the resulting mixture is cooled in an ice bath for 1 hr. The solid is collected, rinsed with cold methanol-water (1 1), air-dried, and finally dried in a vacuum oven at 60° yield, 71.5 g (81 % based on estrone methyl ether actually carried into the Birch reduction as the ketal) mp 139-141°, reported mp 141-141.5°. The material has an enol ether assay of 99%, a residual aromatics content of 0.6% and a 19-norandrost-5(10)-ene-3,17-dione content of 0.5% (from hydrolysis of the 3-enol ether). It contains less than 0.1 % of 17-ol and only a trace of ketal formed by addition of ethanol to the 3-enol ether. 

This dibromide in 640 ml of methanol is refluxed 2 hr with 35 g of potassium hydroxide in 35 ml of water. At the end of this period the methanol is removed in vacuo, replaced with water and the aqueous solution extracted... 

The filtrate is diluted with 140 ml of 50% methanol-water and placed in the refrigerator for 3 days. The thick sheet of crystalline material which forms on the surface is removed by filtration and washed with 75 % acetic acid to yield 32.5 g of crude product. The filtrate is again cooled overnight and an additional 8.7 g of solid is removed. The crops are combined and the material, mp 120-124°, which is highly colored due to chromium salts, is recrystallized twice from methanol to yield 27 g (24 %) of the keto acid (69) mp 127-129° 78° (CHCI3). 

The thus-obtained residue was dissolved in a mixture of 268 ml of methanol and 26.8 ml of 3N aqueous sulfuric acid and heated under reflux for 40 minutes, with a color change from yellow to green. The reaction mixture was then cooled, neutralized by addition of 127 ml of 5% sodium bicarbonate solution, and concentrated under reduced pressure until almost all the methanol was removed. The resulting solid was removed by filtration, washed with water, dried, and twice crystallized from ethyl acetate to give 1.1 g of 11/3-hydroxy-Ba-methylprogesterone having a MP of 155° to 158°C, according to U.S. Patent 2,864,837. 

The column was then eluted with 0.0025N sulfuric acid in methanol-water mixture (1 1 v/v). A total of 900 ml of fractions containing a substance which showed UV absorption at 290 m/u was collected. After removal of methanol by distillation, the residual liquid was adjusted to pH 6.0 with Dowex 44 (OH type) and freeze-dried to obtain 9.3 g (95% yield) of NK631 monosulfate (copper-free form) in the form of pale yellowish-white amorphous powder. 

Figure 5-5. The ICI low-pressure process for producing methanol " (1) desulfurization, (2) saturator (for producing process steam), (3) synthesis loop circulator, (4) reactor, (5) heat exchanger and separator, (6) column for light ends recovery, (7) column for water removal.

The filtrate is concentrated under reduced pressure with a rotary evaporator until most of the methanol is removed. Extract the aqueous residue with degassed butanol in a separatory funnel, of which the inside has been filled with argon in advance. Evaporate the butanol extract under reduced pressure until most of the water is removed. 

A solution of 1 equivalent of the oxazolidinone in diethyl ether is cooled to —78 C. To the resultant suspension are added 1.4 equivalents of triethylamine. followed by 1.1 equivalents of dibutylboryl triflate. The cooling bath is removed and the reaction mixture is stirred at 25 °C for 1.5 h. The resultant two-phase mixture is cooled to — 78 "C with vigorous stirring. After 1 equivalent of aldehyde is added, the reaction is stirred at —78 °C Tor 0.5 h, and 0 "C for 1 to 2 h. The solution is diluted with diethyl ether, washed with 1 N aq sodium bisulfate, and concentrated. Following oxidation with 30% aq hydrogen peroxide (10 equivalents, 1 1 methanol/water, 0 C. 1 h), extractive workup and chromatographic purification, the aldol adduct is obtained with >99% diastcrcomeric purity. 

ABA type poly(hydroxyethyl methacrylate) (HEMA) and PDMS copolymers were synthesized by the coupling reactions of preformed a,co-isocyanate terminated PDMS oligomers and amine-terminated HEMA macromonomers312). Polymerization reactions were conducted in DMF solution at 0 °C. Products were purified by precipitation in diethyl ether to remove unreacted PDMS oligomers. After dissolving in DMF/toluene mixture, copolymers were reprecipitated in methanol/water mixture to remove unreacted HEMA oligomers. Microphase separated structures were observed under transmission electron microscope, using osmium tetroxide stained thin copolymer films. 

Method A. In this procedure, V was dissolved in 5 mL of the liquid to be derivatized, and the mixture was heated for 30 min at 60 C. The solvent was removed under reduced pressure, and the residue was crystallized from a methanol-water solution. 

The catalyst is washed thoroughly with 100 ml. of water and with 200 ml. of absolute methanol to remove all traces of water, after which it is transferred to the flask under nitrogen with a minimal amount of absolute methanol. To be effective the catalyst must be pyrophoric, and extreme care must be taken during this operation to prevent ignition of the methanol or ammonia. The catalyst must not be allowed to become dry or to collect on the wall of the flask above the surface of the liquid ammonia. 

The synthesis of C S-Au nanoparticles as a source for the heat treatment followed the Ernst s two-phase (toluene/water) reaction procedure [3]. The organic (toluene) phase was then separated, evaporated completely in a rotary evaporator at 40 °C, and dried in vacuo at 30 °C for a day. The crude solid obtained was heat treated at 150-250 °C at the heating rate of 2°Cmin, and held for 30 min. The heat-treated product was dissolved in toluene and mixed with methanol to remove excess free C12SH and TOAB. The dark brown precipitate... 

Glycosidic anthraquinones may be developed using ethyl acetate-methanol-water systems (100 10 10) with suitable adjustments made for polarity. Similarly, aglycones can be separated using a somewhat less polar solvent such as petroleum ether (40 to 60°C)-ethyl acetate-formic acid (75 25 1). Some chosen retention data may be found in a recent monograph [24]. Pigments may be recovered by extraction of the absorbant with acetone or methanol after removal of the individual zones. 

The most critical decision to be made is the choice of the best solvent to facilitate extraction of the drug residue while minimizing interference. A review of available solubility, logP, and pK /pKb data for the marker residue can become an important first step in the selection of the best extraction solvents to try. A selected list of solvents from the literature methods include individual solvents (n-hexane, " dichloromethane, ethyl acetate, acetone, acetonitrile, methanol, and water ) mixtures of solvents (dichloromethane-methanol-acetic acid, isooctane-ethyl acetate, methanol-water, and acetonitrile-water ), and aqueous buffer solutions (phosphate and sodium sulfate ). Hexane is a very nonpolar solvent and could be chosen as an extraction solvent if the analyte is also very nonpolar. For example, Serrano et al used n-hexane to extract the very nonpolar polychlorinated biphenyls (PCBs) from fat, liver, and kidney of whale. One advantage of using n-hexane as an extraction solvent for fat tissue is that the fat itself will be completely dissolved, but this will necessitate an additional cleanup step to remove the substantial fat matrix. The choice of chlorinated hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride should be avoided owing to safety and environmental concerns with these solvents. Diethyl ether and ethyl acetate are other relatively nonpolar solvents that are appropriate for extraction of nonpolar analytes. Diethyl ether or ethyl acetate may also be combined with hexane (or other hydrocarbon solvent) to create an extraction solvent that has a polarity intermediate between the two solvents. For example, Gerhardt et a/. used a combination of isooctane and ethyl acetate for the extraction of several ionophores from various animal tissues. 

Solid palladium scavengers, PVPy, QTU were pmchased from commercial somces. The mesoporous silica material, S102-SH, was prepared via reaction of SBA-15 (110 A pore diameter) with 3-mercaptopropyltrimethoxysilane (16). Specifically, a toluene suspension of SBA-15 and 3-mercaptopropyltrimethoxysilane was heated at reflux for two days under Ar. Water was then added to promote the cross-linking and the mixture was heated at reflux for an additional day. The sohds were filtered and washed with copious amounts of toluene, hexanes, and methanol to remove unreacted silanes. The solids were finally Soxhlet extracted with dichloromethane at reflux temperature for 3 days, dried, and stored in a nitrogen dry box. The final solid contained 7.5 wt% sulfur (2.3 mmole S/g solid). 

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