2- Propanol-water-lithium

Isothermal vapor-liquid equilibrium data at 75°, 50° and 25° C for the system of 2-propanol-water-lithium perchlorate were obtained by using a modified Othmer still. In the 2-propanol-rich region 2-propanol was salted out from the aqueous solution by addition of lithium perchlorate, but in the water-rich region 2-propanol was salted in. It is suggested from the experimental data that the simple electrostatic theory cannot account for the salt effect parameter of this system. 

The isothermal vapor-liquid equilibrium data at 75°, 50°, and 25°C for the 2-propanol-water-lithium perchlorate system are listed in Tables I and II. It can be seen from these tables that in the alcohol-rich region the vapor phase composition of 2-propanol increases with an increase in salt concentration. However, in a mixed solvent of 10 mol % alcohol the change of the vapor phase composition is small, and at a temperature of 50° and 25°C it even decreases a... 

The thermodynamic excess functions for the 2-propanol-water mixture and the effects of lithium chloride, lithium bromide, and calcium chloride on the phase equilibrium for this binary system have been studied in previous papers (2, 3). In this paper, the effects of lithium perchlorate on the vapor-liquid equilibrium at 75°, 50°, and 25°C for the 2-propanol-water system have been obtained by using a dynamic method with a modified Othmer still. This system was selected because lithium perchlorate may be more soluble in alcohol than in water (4). 

Jacobsen (1999) has carried out carbomethoxylation of asymmetric epoxides. Thus, the carbomethoxylation of (R)-propylene oxide with CO and methanol yields 92% of (3R)-hydroxybutanoic acid in greater than 99% ee. Similarly, the reaction of (/ )-epichlorohydrin gives 96% of 4-chloro-(3R)-hydroxybutanoic acid in greater than 99% ee. The catalyst consists of dicobalt octacarbonyl and 3-hydroxy pyridine. A continuous process for making enantiomeric 1-chloro-2-propanol has been suggested. With a suitable catalyst propylene reacts with O2, water, cupric and lithium chloride to give 78% of (S)-l-chloro-2-propanol in 94% ee. 

The synthesis of halcinonide is summarized in Figure 1, starting with 16a-hydroxy-9a-fluorohydrocortisone (A1 -pregnene-9a-fluoro-llg,16a,17a,21-tetrol-3,20-dione dihydrotriamcinolone, I), which is available commercially.10-13 This tetrahydroxy steroid is slurried in acetone, and then 70% perchloric acid is added slowly. The acetonide, II (9a-fluoro-llg, 16a, 17, 21-tetrahydroxypregn-4-ene-3, 20-dione, cyclic 16,17-acetal with acetone dihydrotriamcinolone-acetonide) precipitates spontaneously from solution. Mesyl chloride is added to the acetonide in pyridine to give the 21-mesylate derivative (dihydrotriamcinolone acetonide-21-mesylate, III). Compound III is dissolved in dimethylformamide, lithium chloride is added and the mixture is refluxed to produce halcinonide (IV), which is recrystallized from a solution of ft-propanol in water. 

Cabon tetrachloride, n-hexane, chloroform, ACN, acetone, THF, pyridine, acetic acid, and their various mixtures were applied as mobile phases for adsorption TLC. Methanol, 1-propanol, ACN, acetone, THF, pyridine and dioxane served as organic modifiers for RP-TLC. Distilled water, buffers at various pH (solutions of and dipotassium hydrogen phosphate or potassium dihydrogen phosphate) and solutions of lithium chloride formed the aqueous phase. Carotenoids were extracted from a commercial paprika sample by acetone (lg paprika shaken with 3 ml of acetone for 30 min), the solution was spotted onto the plates. Development was carried out in a sandwich chamber in the dark and at ambient temperature. After development (15 cm for normal and 7cm for HPTLC plates) the plates were evaluated by a TLC scanner. The best separations were realized on impregnated diatomaceous earth stationary phases using water-acetone and water-THF-acetone mixtures as mobile phases. Some densitograms are shown in Fig.2.1. Calculations indicated that the selectivity of acetone and THF as organic modifiers in RP-TLC is different [14],... 

Materials. Distilled water was used 2-propanol and trihydrous lithium perchlorate, of guaranteed reagent quality from Wako Pure Chemicals Co., were used without further purification. The purity of the 2-propanol was checked by gas chromatography, with Porapak-Q as the column packing, and found to be more than 99.9 mol %. The physical properties of pure solvents were compared with the literature values in a previous paper (2), and the agreement was satisfactory. 

The salt effect parameter ko is plotted in Figure 2, and the data for lithium chloride and lithium bromide reported in the previous paper (3) are also plotted for the purposes of comparison. It can be seen from Figure 2 that ko depends markedly on the solvent composition. The values of ko decrease and in the extremely water-rich region k0 is negative at 50° and 25°C. In other words, 2-propanol is salted in by the addition of lithium perchlorate. The salting-in effect of 2-propanol increases with reduction in temperature. 

Caution. The residual material in the junnel may include highly activated lithium. It should not come in contact with water and should be destroyed with 2-propanol. 

A solution of 10.74 g (60 mmol) of (17 .25)-2-dimethylamino-l-phenyl-l-propanol in 300 mL of diethyl ether is added dropwise over 1 h to a solution of 2.28 g (60 mmol) of lithium aluminum hydride in 69 mL of dielhyl ether. After standing for 30 min at r.t., a solution of 14.64 g (120 mmol) of 3,5-dimethylphenol in 100 mL of diethyl ether is added dropwise over 30 min. The mixture is kept at r.t. for 2 h and then cooled to — 15 °C. 6.0 g (50 mmol) of 1 -phenylethanonc in 30 mL of diethyl ether is added dropwise over 2 h. After complete addition, the mixture is kept at 15 for 1 h, then hydrolyzed with dil aq Na2C03. The organic phase is washed with two 100-mi. portions of 2 N hydrochloric acid, with two 100-mL portions of 2 N aq sodium hydroxide, and then with water until the water is neutral. The organic phase is dried with Na2S04 and evaporated to give a quantitative yield of (AH-phcnylethanol which is distilled yield 5.4 g (90%) bp 100rC/l8 Torr [ijjp +36.45 (neat, d = 1.019) 84% cc. (1 /<,2.S )-2-Dimethylammo-1 -phenyl-1 -propanol can be recovered from the acid wash. 

The literature dealing with the polyelectrolyte behavior of nylons in fluori-nated alcohols is somewhat controversial. In solutions of i lon 6 and 6,6 in 2,2,3,3-tetrafluoropropanol, some authors observed the polyel rtrolyte efifi which they suppressed with trifluoroacetate lithium chloride or water . Other authors ex dained the polyelectrolyte effect in 2,2,3,3-tetrafluoropropanol solutions by the presence of traces of water while assuming that salt suppresses this effect not by raising the ionic strength of solution, but by binding traces of water. The polyelectrolyte effect was not oteerved in 2,2,3,3-tetrafluoropropanol solutions of nylon 2,2,2-trifluoroethanol solutions of nylon 6 , octafluoro-propanol solutions of nylon 6,6 ) and 1,1,1,3,3,3-hexafluoro-2-propanol solutions ofnytonl2 >. 

The aUcoxide-salt method has been successfully used in the synthesis of compounds of complex stoichiometries as well. One example (Shen et al., 2002) is the synthesis of nanocrystalline Li4TisOi2. The two cation-sources were tetrabutyl titanate and lithium acetate with solvents like 2-propanol, acetic acid and water. Aging of the mixed solution led to the formation of a white gel that was dried and calcined to obtain the crystalline target product. The titanate crystallized as the single phase at 800°C the average size of the particles was 100 nm. 

The original screening study used mefeylamine, potassium bicarbonate, potassium carbonate, ethanolamine, lithium hydride, dibasic potassium phosphate, potassium t-butoxide, DBU, potassium mefeoxide and N,N-diisopropylefeylamine as representative bases. Solvents included in fee screen were water, tetrahydrofuran, acetonitrile, ethyl acetate, methanol, ethanol, and 2-propanol. A tofel of 66 experiments was performed using 50 pinole (12 mg) of substrate, 2 equivalents of base, and 0.2 mL of solvent in each reaction. All... 

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