Methylene chloride/pentane

N)3C.CH20C(CH2)7C0CH2C(N02)3 mw 514.36, N 15.97%, OB to C02 -59% liq, frp —10° sol in methylene chloride-pentane impact sensitivity 90cm (for 50% point on BM Machine). It was prepd by heating slowly at 65°azelaic acid chloride trinitroethanol over a period of 4 his. The reaction mixt was allowed to stand overnight, washed with water and recrystd at low temp from methylene chloride-pentane. This compd may be useful as plasticizers or desensitizers of expls (Ref 3)... 

Vinyltrimethylsilane (97%), trimethylchlorosilane (98%), chlorodimethylsilane (97%), bromoform (96%), 5-bromo-l-pentene (95%), nBuLi (2.5M solution in hexanes), MeLi (1.6M solution in diethyl ether), n-decane (puriss. p.a., standard for GC, > 99.8%) and hexachloroplatinic(lV) acid hydrate were purchased from Aldrich. Platinum divinyltetramethyldisiloxane complex (Karstedt s catalyst, 3% solution in xylenes), hexamethyl-cyclotrisiloxane (95%), vinylmethyldichlorosilane (97%) and 1,1,3,3-tetramethyldisiloxane (97%) were bought from ABCR. Bromine (puriss) was bought from Eluka. Triethylamine (pure for analysis) and zinc oxide (pure) was purchased from Chempur. Solvents (tetrahydrofurane, diethyl ether, methylene chloride, pentane, ethyl acetate) were supplied by POCh (Polish Chemical Reagents). 

Solubility sol in both polar and nonpolar aprotic solvents like diethyl ether, THF, methylene chloride, pentane, hexane, etc. 

Water as the sole blowing agent is not practical for producing these foams, because it results in extremely high-friability foams which make it very difficult to handle in practical applications. An alternative method proposed by Ashida involves the use of specific solvent blends, e.g., an 80/20 blend of methylene chloride/pentane (196). Advantages of this solvent blend are ... 

The synthesis of molecular nitrogen complexes has been achieved by the oxidation of rhodium(i) complexes, by treatment of Rh(CO)PPhs(acac) with hydrazoic acid in a methylene chloride-pentane mixture at — 60 °C in... 

From Boron Halides. Using boron haUdes is not economically desirable because boron haUdes are made from boric acid. However, this method does provide a convenient laboratory synthesis of boric acid esters. The esterification of boron haUdes with alcohol is analogous to the classical conversion of carboxyUc acid haUdes to carboxyUc esters. Simple mixing of the reactants at room temperature or below ia a solvent such as methylene chloride, chloroform, pentane, etc, yields hydrogen haUde and the borate ia high yield. 

JA173) illustrates this possibility (Scheme 34). Thus 3,3,5-trimethyl-3//-pyrazole (371 R = H) on irradiation in pentane solution gives 1,3,3-trimethylcyclopropene (372 R = H) the intermediate diazoalkene (373) has been characterized. The tetramethyl derivative (371 R" = Me) when irradiated at -50 °C in methylene chloride leads to a species believed to be a l,2-dlazablcyclo[2.1.0]pent-2-ene (374). This isomerization is thermally reversible, the 3H- pyrazole being regenerated at room temperature. 

The organic layer is separated, evaporated on a steam bath, and the dark semicrystalline residue is distilled with steam to remove biphenyl. The contents of the steam-distillation flask are then extracted with ether (Note 3), and the ethereal layer is separated, dried over magnesium sulfate, and percolated through a short column of chromatographic alumina (Notes 4 and 5). Evaporation of the ethereal solution gives crude triphenylene which is sublimed at 175-180° and 0.1 mm. pressure. After rejection of an initial sublimate of impure biphenyl, the sublimed material forms nearly colorless crystals, m.p. 186-194° (Note 6). Yield 8-9 g. (53-59%). It may be further purified by recrystallization from a mixture of methylene chloride and pentane yielding colorless crystals, m.p. 199° (Note 7). 

The checkers carried out this recrystallization by dissolving triphenylene in a minimum of methylene chloride maintained at reflux. Pentane was slowly added to this solution up to 90% recovery was achieved. 

The third procedure illustrated by this preparation involves the reaotion of ketones with trifluoromethanesulfonic anhydride in a solvent such as pentane, methylene chloride, or carbon tetrachloride and in the presence of a base such as pyridine, lutidine, or anhydrous sodium carbonate.7-11,15 This procedure, which presumably involves either acid-catalyzed or base-catalyzed enolization of the ketone followed by acylation of the enol with the acid anhydride, has also been used to prepare other vinyl sulfonate esters such as tosylates12 or methanesulfonates.13... 

Mechanistically, the reaction in pentane with up to 35% methylene chloride is proposed to occur via a-cleavage (equations 133 and 134). Other reactions in chloroform, carbon tetrachloride and 65% methylene chloride are proposed to occur by electron transfer to the chlorocarbon with initial formation of di-terf-butyloxoammonium chloride 290 and... 

One particular method is designed to characterize Ce to C28+ petroleum hydrocarbons in soil as a series of aliphatic and aromatic carbon range fractions. The extraction methodology differs from other petroleum hydrocarbon methods because it uses n-pentane, not methylene chloride, as the extraction solvent. If methylene chloride is used as the extraction solvent, aliphatic and aromatic compounds cannot be separated. 

Demethylation reactions proceed equally well using dry M-pentane or dry methylene chloride as the solvent for both the ether and the boron tribromide methylene chloride, having by far the more powerful solvent action, is to be preferred. 

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. ... 

Soluble in alcohol, ether (Weast, 1986), and many low molecular weight hydrocarbons (pentane, hexane, heptane), and halogenated hydrocarbons such as chloroform, methylene chloride, trichloroethylene. 

The reaction mixture is poured slowly into a vigorously stirred solution of 28 ml. (0.28 mole) of concentrated hydrochloric acid and 350 ml. of ice water placed in a 1-1. threenecked round-bottomed flask fitted with an efficient stirrer and immersed in an ice bath (Note 7, Note 8). The mixture is stirred for 20 minutes with ice cooling and extracted three times with 200-ml. portions of a 3 1 (vjv) mixture of ether and methylene chloride. The extracts are washed with three 200-ml. portions of aqueous 2M sodium hydroxide, two 200-ml. portions of water, and one 200-ml. portion of saturated aqueous sodium chloride, and then dried over anhydrous sodium sulfate, and evaporated under reduced pressure (Notes 9 and 10). The crystalline residue, weighing 2.70 g., is recrystallized by dissolving it in 7.5-8 ml. of hot (almost boiling) benzene and adding 25 ml. of n-pentane (distilled) to the hot solution (Note 11). 3j3-Acetoxy-5a-cyanocholestan-7-one is obtained as white crystals, m.p. 192.5-193.5° the yield is 2.27-2.41 g. (86—91%). A second crop can be obtained in 50—170 mg. yield, m.p. 188.5-190° (Note 12) the total yield is 92-93% (Notes 13 and 14). 

Distinctions between water-soluble fractions of mixed hydrocarbons may be made by using solvent extraction of the water-soluble base/neutral and acid fractions with methylene chloride (EPA 1991c Thomas and Delfino 1991a). This separation of base/neutral and acid fractions will permit the GC resolution of the type of water soluble hydrocarbons present in the aqueous phase. Hexane has also been used as a solvent (DellAcqua and Bush 1973), as has pentane (Coleman et al. 1984). 

Carotenoids A large number of solvents have been used for extraction of carotenoids from vegetables matrices, such as acetone, tetrahydrofuran, n-hexane, pentane, ethanol, methanol, chloroform [427-431], or solvent mixtures such as dichloromethane/methanol, tetrahydrofuran/methanol, -hexane/acetone, or toluene or ethyl acetate [424,432-435], SPE has been used as an additional purification step by some authors [422,426], Supercritical fluid extraction (SEE) has been widely used, as an alternative method, also adding CO2 modifiers (such as methanol, ethanol, -hexane, water, methylene chloride) to increase extraction efficiency [436-438], In addition, saponification can be carried out, but a loss of the total carotenoid content has been observed and, furthermore, direct solvent extraction has been proved to be a valid alternative [439],... 

Intersystem crossing rate constants of ortho- and meta-substituted singlet phenylni-trenes are presented in Table 1Mono- and di-o-fluorine substituents have no influence on ISC rate constants.No effect with meta, meta-difluoro substitution is observed either. Pentafluoro substitution has no effect on fcisc in pentane although a modest acceleration is observed in the more polar solvent methylene chloride.i° - i... 

Extraction with methylene chloride evaporate clean up on silica gel followed by clean up on alumina and on a carbon/silica gel column Extract with 2-propanol/hexane clean up with Lipidex 5000, column chromatography/GPC Extract with potassium oxalate/ethanol/diethyl ether/pentane GPC clean up on Florisil elute with hexane... 

Figure 4. Profiles of volatiles for high-quality peanuts, raw and roasted (1) ethanol (2) pentane (3) 2-propanol (4) acetone (5) methylene chloride (6) methyl acetate (7) 2-methylpropanal (8) diacetyl (9) 3-methylbutanal (10) 2-methyl-butanal (11) 2,3-pentanedione (12) S-methylpyrrole (13) toluene (14) hexanal (15) 2-methylpyrazine (16) xylene (17) 2-heptanone (18) 2,5-dimethylpyrazine (19) 2-pentylfuran (20) 2-ethyl-5-methylpyrazine (21) 2-ethyl-3,6-dimethylpyra-zine (22) phenylacetaldehyde.

In combination with temperature, the SFE pressure control, through density variation, the solvating power of CO2. For CO2, low pressures such as 75 bar (1090 psi, 80 C, d 0.1.5 g/ml) correlate to a solvent power analogous to pentane. For higher pressures such as 380 bar (5550 psi, 40 C, d 0.95 g/ml), the solvent power is more similar to liquid solvents such as methylene chloride, carbon... 

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