Methanol combinations

A solution of 4.8 g of sodium in 300 ml of anhydrous liquid ammonia (note 1) was prepared by introducing the sodium, cut into 1-g pieces, into the ammonia. When the sodium had dissolved (after 10 min), 0.12 mol of selenium was added in 0.5-g portions over a period of 10 min with vigorous stirring. A dropping funnel, containing 250 ml of methanol, combined with a gas inlet was then placed on the neck... 

Shake 25 g (dry weight equivalent) of soil with 100 mL of methanol with a mechanical shaker for 30 min. Filter the mixture through a filter paper into a 300-mL round-bottom flask. Wash the filter cake with 80 mL of methanol, combine all the filtrates in the round-bottom flask and remove the methanol by rotary evaporation. 

Weigh 50 g (dry soil) of the sample into a 500-mL round-bottom flask, add 160 mL of 6 M NaOH-methanol (1 3, v/v) and reflux the mixture at 70 °C for 1 h. Filter the extract through a filter paper overlaid with 20 g of Celite in a Buchner funnel into a 1-L round-bottom flask with suction. Rinse the flask and the filter cake twice with 30 mL of methanol. Combine the filtrates and concentrate to approximately 40 mL under reduced pressure. Neutralize the residue with 6 N HCl. Then the residue is processed as described in Section 6.2.1. 

LCM [Leading Concept for Methanol] A process for making methanol, combining the ICI Low Pressure Methanol process with the steam reforming section of the LCA ammonia process. Developed by ICI in 1990 and piloted in Melbourne, Australia, from 1994. Envisaged for floating factories in off-shore gas fields. 

Filter as before and extract again with about 300 ml of methanol. Combine the residues of all extractions and hydrolyze. 

The results presented in Table VI for the 42 organochlorine pesticides extracted from spiked sand indicate that SFE with carbon dioxide worked reasonably well for 35 of the 42 compounds (recovery > 50 percent) from those 35 compounds, 30 compound had recoveries > 70 percent. Among the seven compounds with recoveries < 50 percent, two are very volatile (DBCP and hexachlorocyclopentadiene). Three of the remaining five compounds (chlorthalonil, captan, and endosulfan sulfate) gave very poor recoveries with carbon dioxide alone, probably because of their polarity however, in other experiments we have recovered them quantitatively from spiked sand with carbon dioxide modified with 10 percent methanol (1). Chlorobenzilate recoveries were poor, even when we used carbon dioxide with 10 percent methanol, and captafol was not tested with the carbon dioxide/methanol combination. 

The crossover of methanol has caused problems in finding a suitable membrane material. On the positive electrode side, methanol combines with oxygen to form CO2. Among the alternatives to pure Nafion are Nafion filled with zirconium phosphate or grafted with styrene to inhibit methanol transport (Bauer and Willert-Porada, 2003 Sauk et al., 2004), as well as non-Nafion membrane materials such as sulfonated polyimide (Woo et al., 2003). None have achieved performance as good as the one shown in Fig. 3.53, which, however, has a substantial methanol crossover rate. 

Higher concentration solutions and minimum solution concentrations result from methanol and methanol-heptane. Substituting toluene for heptane in the methanol combinations enables higher concentrations of solutions than does methanol alone, but no minimum solution conditions result. 

Sodium salt, CggH N NaOgS, cilastatin sodium. Off-white to yellowish-white hygroscopic, amorphous solid. pKa, 2.0 pKa2 4.4 pKa, 9.2. Very sol in water, methanol. Combination with imipenem Primaxin, Zienam. 

More recently, by moving from group 11 to group 10, Pt(II) catalysts were developed for the tandem reaction of 2,4-pentanediones with aminoalkynes to access indolines and tetrahydroquinolines (Scheme 15.119) [358]. The use of the protic solvent methanol, combined with molecular sieves, provided the desired products in optimized yields. The use of microwave heating could reduce the reaction times to approximately 2 h, while giving excellent yields (up to 99%). 

NOTE. If the sodium/methanol combination is used, it is not necessary to heat the mixture. A fairly vigorous reaction occurs at room temperature. It is recommended that the instructor cut the Na/K metal before commencing the laboratory. 

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