2- Methoxyethanol, oxidation

A 1/1,2/1 mixture of 2-methoxyethanol/polyacrylamide + hydrogen per-oxide/toluene respectively volatilised slowly and intermittently by heating over a period of four weeks. The detonation was explained by the ether-alcohol oxidation by the peroxide. 

Korkisch and Koch [106,107] determined low concentrations of uranium in seawater by extraction and ion exchange in a solvent system containing trioctyl phosphine oxide. Uranium is extracted from the sample solution (adjusted to be 1 M in hydrochloric acid and to contain 0.5% of ascorbic acid) with 0.1 M trioctylphos-phine oxide in ethyl ether. The extract is treated with sufficient 2-methoxyethanol and 12 M hydrochloric acid to make the solvent composition 2-methoxyethanol-0.1 M ethereal trioctylphosphine acid-12 M hydrochloric acid (9 10 1) this solution is applied to a column of Dowex 1-X8 resin (Cl" form). Excess of trioctylphosphine oxide is removed by washing the column with the same solvent mixture. Molybdenum is removed by elution with 2-methoxyethanol-30% aqueous hydrogen peroxide-12 M hydrochloric... 

Scheldt and co-workers have also illustrated the oxidation of activated alcohols to esters [132], Oxidations of alcohols such as 260 provide the electrophile (acyl donor) for a nucleophilic alcohol 261. Esters 262 are derived from propargylic, allylic, aromatic, and hetero-aromatic substrates (Table 20). The nucleophilic alcohol scope includes MeOH, n-BuOH, f-BuOH, 2,2,2-trichloroethanol, 2-methoxyethanol, and 2-(trimethylsilyl) ethanol. 

Oxidation of 2-methoxyethanol or 1,2-ethanediol by [0s04], in the presence of a porphyrin, is used to prepare [Osn(P)(CO)(X)] complexes [P is a porphyrinato(2-) ligand] (139). Recently, more convenient preparations of porphyrinato complexes were developed using the reactions of LOs3(CO)i2] with the appropriate porphyrin (Section II,C,4,d) (38, 40, 140,141). Electrochemical studies show that both the Os(III) and Os(III)/porphyrin-cation-radical complexes are moderately stable... 

The properties, crystal habit, and x-ray pattern of tungsten(IV) dichloride oxide are very similar to those of molybdenum(IV) dichloride oxide.8 Stoichiometric tungsten(IV) dichloride oxide, which forms gold-brown needles, is stable under atmospheric conditions and is not attacked by water, dilute or concentrated cold acids, ammonia, or organic solvents, such as acetone, ethanol, 2-methoxyethanol, chloroform, and diethyl ether. However, it decomposes in a solution of sodium hydroxide and forms a black precipitate, which disappears when hydrogen peroxide is added and yields a clear, yellow solution. The density of tungsten(IV) dichloride oxide, determined pycnometrically as previously mentioned, is 5.92 g./cc. 

Tungsten(VI) tetrabromide oxide is a dark-brown crystalline compound, which is obtained in the form of needles or flakes. It is extremely sensitive to atmospheric moisture, decomposes rapidly in water, which leaves a gray-green precipitate, and is completely dissolved in solutions of ammonia or sodium hydroxide, which form clear, colorless solutions. It is slightly soluble in concentrated hydrochloric acid, dioxane (yellow solution), 2-methoxyethanol (colorless solution), and acetone (green solution). It has a melting point of 322°C., as determined by D.T.A. 

Few data are available on the hydrolysis of simple metal alkoxides of these elements. Alkoxides of alkaline and alkaline earth metals are mostly used as precursors for the preparation of complex oxides or solid oxide solutions. Commercial production of pure magnesium oxide by hydrolysis of Mg(OMe)2 with formation of transparent gel has been described [715], as well as hydrolysis of Mg(OC5H11i)2 with the following thermal treatment to produce a fine MgO powderthat sinters at low temperatures [1766]. Solutions prepared by dissolving magnesium in methoxyethanol are by far the most convenient precursors for preparation of magnesium oxide films. 

Chloranil oxidation. To 17.86 g of a suspension of the leuco-l,4-bis[2-(2-hydroxyethylamino)ethylamino]-5,8-dihydroxyanthraquinone (0.03 mole) in 2-methoxyethanol was added gradually with stirring 15 ml of 8 N ethanolic hydrogen chloride. The system was chilled with an ice bath and stirred as 7.50 g (0.0305 mole) of chloranil powder was gradually added. The mixture was stirred overnight at room temperature and diluted with 600 ml of ether. The solid was collected and washed with tetrahydrofuran. Yield of l,4-bis[2-(2-hydroxyethylamino)ethylamino]-5,8-dihydroxyanthraquinone dihydrochloride 21.34 g, melting point 203-205°C (without recrystallisation). 

The reaction chemistry of simple organic molecules in supercritical (SC) water can be described by heterolytic (ionic) mechanisms when the ion product 1 of the SC water exceeds 10" and by homolytic (free radical) mechanisms when <<10 1 . For example, in SC water with Kw>10-11 ethanol undergoes rapid dehydration to ethylene in the presence of dilute Arrhenius acids, such as 0.01M sulfuric acid and 1.0M acetic acid. Similarly, 1,3 dioxolane undergoes very rapid and selective hydration in SC water, producing ethylene glycol and formaldehyde without catalysts. In SC methanol the decomposition of 1,3 dioxolane yields 2 methoxyethanol, il lustrating the role of the solvent medium in the heterolytic reaction mechanism. Under conditions where K klO"11 the dehydration of ethanol to ethylene is not catalyzed by Arrhenius acids. Instead, the decomposition products include a variety of hydrocarbons and carbon oxides. 

The pKa values of perhydropyridof 1,2-a]pyrazin-l -one, its 2-methyl derivative and their N-5 oxides were determined by potentiometric titration in a 4 1 mixture of 2-methoxyethanol and H20 (81BAP423).The partition coefficients of 3-substituted 2,3,4,4a,5,6-hexahydro-l//-pyrazino[l,2-a]-quinolines have been determined in water-l-octanol [80IJC(B)879],... 

Polyethylene oxide)macromonomers have thus been synthesized by two-step processes. Poly(oxyethylene)mo nomethyl ethers with widely varying molecular weights are commercially available. They are obtained by anionic polymerization of oxirane initiated by monofunctional alkoxides261 such as potassium 2-methoxyethanol. 

The flame decompositions of 2-hydroxyethyl nitrate, 2-methoxyethyl nitrate and 2-ethoxyethyl nitrate have been studied using a flat flame burner [135]. The major products of very rapid reaction in the flame front are nitric oxide, carbon monoxide, water, formaldehyde, methyl formate, methanol and a large amount of unidentified material. The absence of 2-methoxyethanol and of nitrogen dioxide, and presence of only minor amounts of dimethyl ether is of some importance. 

The most interesting result is the formation of a transparent colloidal solution of ceria with 2 nm particles. Cerium metal tips with the superficial layers of oxide are allowed to react in 2-methoxyethanol at 250 to 300°C, and removal of coarse ceria particles originating from the superficial layers yields the colloidal solution. Addition of water to the solution does not cause any change except dilution of the color of the solution, but addition of a drop of a solution of any kind of salt immediately causes precipitation of ceria particles. - The reaction mechanism is as follows The solvent slowly dissolves the superficial layers, and when the solvent reaches the metal, rapid reaction occurs, yielding an alkoxide solution. The concentration of the ceria precursor becomes so high that a burst of nucleation occurs, yielding the colloidal solution. The reaction of cerium acetylacetonate in the same solvent yields ceria particles but does not give a colloidal solution. 

A great advantage of electrochemical reactions compared with chemical conversions is the effective contribution to pollution control. The direct electron transfer from the electrode to the substrate avoids the problem of separation and waste treatment of the frequently toxic end products of the chemical oxidants or reductants. Furthermore, by electrodialysis, organic acids or bases can be regenerated from their salts without the use of sulfuric acid or sodium hydroxide, for example, which lead to the coproduction of sodium salts or sulfates as waste [79]. At the same time, inorganic acids and bases, necessary for chemical production, are provided by this process. An application of electrodialysis has been demonstrated in the preparation of methoxyacetic acid by oxidation of methoxyethanol at the nickel hydroxide electrode [80]. Finally, unwanted side products can be converted into the wanted product, which increases the economy of the process and reduces the problem of waste separation and treatment. This is accomplished in the manufacture of chloroacetic acid by chlorination of acetic acid. There the side product dichloroacetic acid, formed by overchlorination, is cathodically converted to chloroacetic acid [81]. 

Methoxyethanol underwent anodic oxidation in acetonitrile to give a number of products, as in Eq. (56) [137]. Both tetrahydrofurfuryl alcohol and tetrahydropyr-anyl methanol have been oxidized indirectly at a nickel hydroxide anode to give a mixture of the corresponding alkoxy acids as well as lactones and ring-opened diacids [136]. 

An unusual reaction reported by Inoue et al. [66] is the direct oxidation of Ce metal in 2-methoxyethanol at temperatures between 200 °C and 250 °C. Most of the product obtained was bulk Ce02 as a yellow solid, but in addition, they obtained a brown solution of 2 nm Ce02 nanoparticles. The Ce02 nanoparticles could be salted out by the addition of NaCl, and redispersed into solution at will. The solutions obeyed the Beer-Lambert law for the concentration dependence of the optical extinction, suggesting that the nanoparticulate dispersion was a genuine solution. 

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