Dioxane/pentane

Data for Dioxane/Pentane and Pyridine/Pentane (Alnmina)... 

Ethanol with acetic acid, acetone, benzene, chloroform, cyclohexane, dioxane, ethyl ether, pentane, toluene, water or xylene. 

Treatment with acetic anhydride and pyridine at room temperature followed by recrystallization of the crude product from chloroform-pentane gives the 3-acetate of (83a) mp 277-279° [aj —101° (dioxane). 

FIGURE 3 2 Solvent extraction efficiencies (EF) as functions of dielectric constants (D), solubility parameters (6), and polarity parameters (P and E -). Solvents studied silicon tetrachloride, carbon disulfide, n pentane. Freon 113, cyclopentane, n-hexane, carbon tetradiloride, diethylether, cyclohexane, isooctane, benzene (reference, EF 100), toluene, trichloroethylene, diethylamine, chloroform, triethylamine, methylene, chloride, tetra-hydrofuran, l,4 dioxane, pyridine, 2 propanol, acetone, ethanol, methanol, dimethyl sulfoxide, and water. Reprinted with permission from Grosjean. ... 

Figure 18. Correlations between the solubility of cmchonidme and the reported empirical polarity (A) and dielectric constants (B) of 48 solvents [66]. Those solvents are indicated by the numbers in the figures 1 cyclohexane 2 n-pentane 3 n-hexane 4 triethylamine 5 carbon tetrachloride 6 carbon disulfide 7 toluene 8 benzene 9 ethyl ether 10 trichloroethylene 11 1,4-dioxane 12 chlorobenzene 13 tetrahydrofuran 14 ethyl acetate 15 chloroform 16 cyclohexanone 17 dichloromethane 18 ethyl formate 19 nitrobenzene 20 acetone 21 N,N-drmethyl formamide 22 dimethyl sulfoxide 23 acetonitrile 24 propylene carbonate 25 dioxane (90 wt%)-water 26 2-butanol 27 2-propanol 28 acetone (90 wt%)-water 29 1-butanol 30 dioxane (70 wt%)-water 31 ethyl lactate 32 acetic acid 33 ethanol 34 acetone (70 wt%)-water 35 dioxane (50 wt%)-water 36 N-methylformamide 37 acetone (50 wt%)-water 38 ethanol (50 wt%)-water 39 methanol 40 ethanol (40 wt%-water) 41 formamide 42 dioxane (30 wt%)-water 43 ethanol (30 wt%)-water 44 acetone (30 wt%)-water 45 methanol (50 wt%)-water 46 ethanol (20 wt%)-water 47 ethanol (10 wt%)-water 48 water. [Reproduced by permission of the American Chemical Society from Ma, Z. Zaera, F. J. Phys. Chem. B 2005, 109, 406-414.]...

Acetyl-2-hydroxy-2-methyl-2,3-dihydrobenzo-l,4-dioxan (42, R = H R = MeCO R = Me) exists as a mixture of two cyclic diastereomers 42B and B, both stabilized by an intramolecular hydrogen bond (42B-Z and 48- ). The proportion of the open-chain tautomer 42A, also containing an intramolecular hydrogen bond in the enolized pentane-l,3-dione moiety, is very small ( 1%) at equilibrium (89ZOR1273). 

LiChrosphr lOODIOL UV254 nm 2,2,4-trimethyl pentane/1,4 dioxane (50/50) Benzoic and gallic acids Dodecyl-, Propyl-, Ethyl-,Methylgallate 37... 

A solution of 1 equiv of (S)- or (/ )-2-methoxymetliyl-1-[(2,2-dimethyl-l,3-dioxan-5-ylidene)amino]pyrro-lidine in THF (4 mL/mmol) is cooled to — 78 °C. 1.1 Equiv of tert-butyllithium in hexane (1.7 M) are added dropwise and the mixture is stirred for 2 h at — 78 °C. The solution of the metalated hydrazone is cooled to — 100 CC, 1.2 equiv of the alkyl halide (neat or as a solution in anhyd THF) are added dropwise, and the mixture is stirred for 1 h at —100 °C and then warmed slowly to r.t. (about 15 h). Finally, diethyl ether (30 mL/mmol) is added and the mixture is washed with pH 7 buffer (3 mL/mmol) and two 3-mL portions of brine, dried over MgSO and evaporated under reduced pressure. The Crude product is heated to 50 C for a short time if necessary (about 15 min for isomerization from the Z- to the L-isotiler monitored by TLC) and purified by silica gel column chromatography (diethyl ether/ pentane, 1 1 -2 5 Rf - > RfZ-iso-mer) to give a colorless or pale yellow product. See Table 2 for physical data. 

The vapor above a 50 1 liquid mixture of 1.4-dioxane and cyclohexane containing a trace of metallic mercury is irradiated in a Rayonet photoreactor for 24 h, which converts >95% of the cyclohexane. Excess dioxane is removed by distillation. The pot residue is triturated with pentane to remove the dioxane dimer. The residual pentane solution is then concentrated to give essentially pure 2-cyclohexvl-1.4-dioxane. 

Hydroxy-4-methyl-3-(4-methyI-benzolsulfonyI-amino)-l-( 2-methyl-1,3-dioxan-2-yl) -pentan 83... 

The acid dissociation constant, pKD, was determined for 4-methylimino-pentane-2-one as a function of mole fraction dioxane and the data conform (within 0.03) to the expression, pKD = 10.78 + 14.19 N2, in the range N2=0.08 to 0.173. The half-neutralized ligand was stable in 50 volume % dioxane for at least an hour. Formation constants could not be determined for the ligand again, hydrolysis was indicated. 

B. Bicyclo[1.1.1]pentane-1,3-dicarboxytic acid (3). A 1-L, three-necked, round-bottomed flask, equipped with a mechanical stirrer, addition funnel, and thermometer is charged with a solution of 43.3 g (108 mol) of sodium hydroxide in 315 mL of water and 25.5 mL (79.1 g, 0.495 mol) of bromine. The mixture is cooled to 0°C. A solution of the diketone (10 g, 0.066 mol) obtained in Part A in 36 mL of dioxane is added dropwise at such a rate that the temperature does not exceed 3°C (Note 7). After the addition is finished, the reaction mixture is stirred for 1 hr at 0°C, then overnight at room temperature. Sodium bisulfite (1.8 g) is added and the solution is extracted with chloroform (3 x 50 mL). Subsequently, 36 mL of coned hydrochloric acid is added to the aqueous layer. After the acidified solution is cooled to room temperature, the mixture is continuously extracted with diethyl ether for 50 hr (Note 8) in an extraction apparatus. Evaporation of ether from the extract yields 9.68 g (94.5% from diketone 2) of pure diacid 3, mp 302-305°C, with decomposition [lit.4 mp, 305°C (d)] (Note 9). 

Amine 30 (108 mg, 0.50 mmol) was dissolved in 0.2 M NaOH (2.5 mL). Boc O (120 mg, 0.55 mmol), dissolved in dioxane (2.5 mL), was added to the soln in an ice bath. The mixture was stirred at rt for 2 h. H20 (15 mL) was added to the mixture, which was then addified with 10% citric acid and extracted with EtOAc (50 mL). The organic layer was washed with 10% citric acid and sat. NaCl, and dried (Na2S04). The soln was filtered and concentrated, affording an oily residue, which was then triturated with an EtOAc/pentane mixture in a strongly cooled bath of dry ice/EtOH. By pipetting off the supernatant, the product 31 was obtained yield 134mg (85%) mp 151-157°C [a]D24 -214 (c 1.0, MeOH). 

Pentane 3-Fluoromcthyl-3-hydroxy-methyl- El Ob,. 130 (subst 2-Oxo-1,3-dioxane 1 KF) 5-Pentanol 2-Fluoromethyl-2-methyl- ElOb, 136 (2-()xo-l,3-dioxan + KF)... 

A. 2-( Bromomethyl)- .-( ehloromethyD-1, -dioxane. A 100-mL, round-bottomed flask is equipped with a 10-mL Dean-Stark apparatus and a condenser. The flask is charged with 30.0 g (0.138 mol) of l-bromo-3-chloro-2,2-dimethoxypropane (Note 1), 10.0 mL (0.138 mol) of 1,3-propanediol (Note 2), and 3 drops of concentrated sulfuric acid. The resulting solution is heated (bath temperature 140°C) for 8 hr (Note 3) with distillative removal of methanol (ca. 11 mL). The mixture is allowed to cool to room temperature and the crude product is partitioned in 150 mL of pentane and 40 mL of water. The... 

Capello et al.16 applied LCA to 26 organic solvents (acetic acid, acetone, acetonitrile, butanol, butyl acetate, cyclohexane, cyclohexanone, diethyl ether, dioxane, dimethylformamide, ethanol, ethyl acetate, ethyl benzene, formaldehyde, formic acid, heptane, hexane, methyl ethyl ketone, methanol, methyl acetate, pentane, n- and isopropanol, tetrahydrofuran, toluene, and xylene). They applied the EHS Excel Tool36 to identify potential hazards resulting from the application of these substances. It was used to assess these compounds with respect to nine effect categories release potential, fire/explosion, reaction/decomposition, acute toxicity, irritation, chronic toxicity, persistency, air hazard, and water hazard. For each effect category, an index between zero and one was calculated, resulting in an overall score between zero and nine for each chemical. Figure 18.12 shows the life cycle model used by Capello et al.16... 

Figure 15 Phase separation conditions of the gas-liquid microflows. Solvents 1,1-decanol 2,1-octanol 3,1-propanol 4, nitrobenzene 5, dodecane 6,1,4-dioxane 7, ethanol 8, water 9, carbon tetrachloride 10, m-xylene 11, hexane 12, toluene 13, chloroform 14, ethyl acetate 15, dichloromethane 16, hexane 17, acetone 18, pentane and 19, diethyl ether. The open circles show the theoretical higher limit, the open triangles the theoretical lower limit, the solid circles the experimental results of the higher limit, and the solid triangles the experimental results of the lower limit (Aota et al., 2009a).

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