Nonpolar organic solvent

The physical properties of a typical amino acid such as glycine suggest that it is a very polar substance much more polar than would be expected on the basis of its formula tion as H2NCH2CO2H Glycine is a crystalline solid it does not melt but on being heated It eventually decomposes at 233°C It is very soluble m water but practically insoluble m nonpolar organic solvents These properties are attributed to the fact that the stable form of glycine is a zwittenon, or inner salt... 

Solubility Properties. Fats and oils are characterized by virtually complete lack of miscibility with water. However, they are miscible in all proportions with many nonpolar organic solvents. Tme solubiHty depends on the thermal properties of the solute and solvent and the relative attractive forces between like and unlike molecules. Ideal solubiHties can be calculated from thermal properties. Most real solutions of fats and oils in organic solvents show positive deviation from ideaHty, particularly at higher concentrations. Determination of solubiHties of components of fat and oil mixtures is critical when designing separations of mixtures by fractional crystallization. 

Titanium Tetraiodide. Titanium tetraiodide [7720-83 ] forms reddish-brown crystals, cubic at room temperature, having reported lattice parameter of either 1200 (149) or 1221 (150) pm. Til melts at 150°C, boils at 377°C, and has a density of 440(0) kg/m. It forms adducts with a number of donor molecules and undergoes substitution reactions (151). It also hydrolyzes in water and is readily soluble in nonpolar organic solvents. 

Properties. Pure vinyHdene chloride [75-35-4] (1,1-dichloroethylene) is a colorless, mobile Hquid with a characteristic sweet odor. Its properties are summarized in Table 1. VinyHdene chloride is soluble in most polar and nonpolar organic solvents. Its solubiHty in water (0.25 wt %) is nearly independent of temperature at 16—90°C (4). 

Phase-tiansfei catalysis (PTC) is a technique by which leactions between substances located in diffeient phases aie biought about oi accelerated. Typically, one OI more of the reactants are organic Hquids or soHds dissolved in a nonpolar organic solvent and the coreactants are salts or alkah metal hydroxides in aqueous solution. Without a catalyst such reactions are often slow or do not occur at ah the phase-transfer catalyst, however, makes such conversions fast and efficient. Catalysts used most extensively are quaternary ammonium or phosphonium salts, and crown ethers and cryptates. Although isolated examples of PTC can be found in the early Hterature, it is only since the middle of the 1960s that the method has developed extensively. 

Direction of Extraction. The "normal" PT process involves the transfer of a reactive agent from a soHd or aqueous environment into a nonpolar organic solvent. But the exact opposite can be executed extraction from an organic phase into an aqueous phase, for example, for changing selectivities. This "inverse PTC" is done relatively rarely. 

Sulfur mortars (mixture of sulfur and inert fillers with small amounts of organic plasticizers) are used for shrinkage mitigation and for eliminating thermal shocks for temperatures up to 80°C. These mortars have poor resistance to alkalis and nonpolar organic solvents. 

Such indicators do not migrate during chromatography to the solvent front under the influence of either polar or nonpolar organic solvents (uranyl acetate is an exception). 

Lipids (Section 26.1) Biologically important natural products characterized by high solubility in nonpolar organic solvents. 

Phase-transfer catalysis describes the action of special catalysts that assist the transfer of reactive molecules from a polar ( aqueous ) solvent to a nonpolar ( organic ) solvent. In the absence of the phase-transfer catalyst, one of the reagents is confined to one solvent, and the other reagent is confined to the other solvent, so no reaction occurs. Addition of a small amount of catalyst, however, enables one of the reagents to pass into the other solvent thereby initiating a reaction. 

Lipids are naturally occurring organic molecules that have limited solubility in water and can be isolated from organisms by extraction with nonpolar organic solvents. Fats, oils, waxes, many vitamins and hormones, and most nonprotein cell-meznbrane components are examples. Note that this definition differs from the sort used for carbohydrates and proteins in that lipids are defined by a physical property (solubility) rather than by structure. Of the many kinds of lipids, we ll be concerned in this chapter only with a few triacvlglycerols, eicosanoids, terpenoids, and steroids. 

Asymmetrical triesters of phosphoric acid of the general formula ROPO (OR,)2 (R = C8 i4 alkyl R, = C, 3 alkyl) were obtained in approximately 70% yield by treatment of a higher fatty alcohol and a Ci 3 alcohol with P0C13 in hexane or pyridine at <0°C. The products were soluble in nonpolar organic solvents and partially soluble in polar organic solvents and water. But the foamforming ability and foam stability of the compounds in water were low [11]. 

All of the known rhenium chalcogenide halides are stable in air. With the exception of RegSgCU, they are insoluble in water, acids, and the common organic solvents. They dissolve readily in hot, 50% KOH (263, 264). Re2S3Cl4 is soluble in water, and ethanol, but insoluble in nonpolar organic solvents. With acids, alkalis, or hot water, hydrolytic decomposition takes place. Alkaline solutions can be oxidized to produce perrhenate compounds. 

Complexes of DNA with cationic detergents were found to behave similarly to the DNA/CL They also are soluble in nonpolar organic solvents and form condensed DNA structures, with one notable exception. The morphology of some of the DNA/detergent... 

Typically, one or more reactants are organic liquids or solids dissolved in a nonpolar organic solvent (RX in Fig. 3.56), while the other reactants are salts or alkali metal hydroxides in aqueous solution (NaY in Fig. 3.56). 

Crown ethers (Fig. 3.57) and cryptands (Fig. 3.58) can solubilize organic and inorganic alkali metal salts even in nonpolar organic solvents they form a complex with the cation (see Fig. 3.57c), and thus act as an organic mask (Gates, 1992). 

This technique is based on the same separation mechanisms as found in liquid chromatography (LC). In LC, the solubility and the functional group interaction of sample, sorbent, and solvent are optimized to effect separation. In SPE, these interactions are optimized to effect retention or elution. Polar stationary phases, such as silica gel, Florisil and alumina, retain compounds with polar functional group (e.g., phenols, humic acids, and amines). A nonpolar organic solvent (e.g. hexane, dichloromethane) is used to remove nonpolar inferences where the target analyte is a polar compound. Conversely, the same nonpolar solvent may be used to elute a nonpolar analyte, leaving polar inferences adsorbed on the column. 

X 10-5 mPa gt25°C Water 1.7 mg L- at 20°C Readily soluble in polar and nonpolar organic solvents... 

As mentioned in the Introduction, in the discussion of liquid electrochemical cells it is necessary to distinguish two groups of immiscible liquid-liquid interfaces water-polar organic solvent, e.g., nitrobenzene, and water-nonpolar organic solvent (water-oil or water-hydrocarbon), e.g., octane type systems. It is schematically presented as... 

The above methods work well for LC fractions in volatile and relatively nonpolar organic solvents. It is much more difficult to apply the same techn to reversed-phase eluents containing an... 

Alkylations of phenoxide ions in water have recently been carefully studied by Breslow et al.57 Alkylation can occur both at the phenoxide oxygen and on ortho and para positions of the ring when the phenoxide has at least one alkyl substituent (Eq. 5.4). Carbon alkylation occurs in water, but not in nonpolar organic solvents. This is attributed to the antihydrophobic effect of the organic solvents. 

For carbon-carbon bond-formation purposes, S 2 nucleophilic substitutions are frequently used. Simple S 2 nucleophilic substitution reactions are generally slower in aqueous conditions than in aprotic organic solvents. This has been attributed to the solvation of nucleophiles in water. As previously mentioned in Section 5.2, Breslow and co-workers have found that cosolvents such as ethanol increase the solubility of hydrophobic molecules in water and provide interesting results for nucleophilic substitutions (Scheme 6.1). In alkylations of phenoxide ions by benzylic chlorides, S/y2 substitutions can occur both at the phenoxide oxygen and at the ortho and para positions of the ring. In fact, carbon alkylation occurs in water but not in nonpolar organic solvents and it is observed only when the phenoxide has at least one methyl substituent ortho, meta, or para). The effects of phenol substituents and of cosolvents on the rates of the competing alkylation processes... 

Breslow and co-workers have found that cosolvents such as ethanol increase the solubility of hydrophobic molecules in water and provide interesting results for nucleophilic substitutions of phenoxide ions by benzylic chlorides carbon alkylation occurs in water but not in nonpolar organic solvents, and it is observed only when the phenoxide has at least one methyl substituent (ortho, meta, or para). This has been discussed in Chapter 6 (Section 6.4.2). 

A significant acceleration of Michael addition was reported by Lubineau in the reaction of nitroalkanes with buten-2-one when the reaction media was changed from nonpolar organic solvents to water... 

Fontes tt al. [224,225 addressed the acid—base effects of the zeolites on enzymes in nonaqueous media by looking at how these materials affected the catalytic activity of cross-linked subtilisin microcrystals in supercritical fluids (C02, ethane) and in polar and nonpolar organic solvents (acetonitrile, hexane) at controlled water activity (aw). They were interested in how immobilization of subtilisin on zeolite could affected its ionization state and hence their catalytic performances. Transesterification activity of substilisin supported on NaA zeolite is improved up to 10-fold and 100-fold when performed under low aw values in supercritical-C02 and supercritical-ethane respectively. The increase is also observed when increasing the amount of zeolite due not only to a dehydrating effect but also to a cation exchange process between the surface proton of the enzyme and the sodium ions of the zeolite. The resulting basic form of the enzyme enhances the catalytic activity. In organic solvent the activity was even more enhanced than in sc-hexane, 10-fold and 20-fold for acetonitrile and hexane, respectively, probably due to a difference in the solubility of the acid byproduct. 

Borazine is miscible with anhydrous nonpolar organic solvents. Its chemical and physical properties have been studied in great detail.8... 

---