Metal aqueous-based

Difluoroethanol is prepared by the mercuric oxide cataly2ed hydrolysis of 2-bromo-l,l-difluoroethane with carboxyHc acid esters and alkaH metal hydroxides ia water (27). Its chemical reactions are similar to those of most alcohols. It can be oxidi2ed to difluoroacetic acid [381-73-7] (28) it forms alkoxides with alkaH and alkaline-earth metals (29) with alkoxides of other alcohols it forms mixed ethers such as 2,2-difluoroethyl methyl ether [461-57-4], bp 47°C, or 2,2-difluoroethyl ethyl ether [82907-09-3], bp 66°C (29). 2,2-Difluoroethyl difluoromethyl ether [32778-16-8], made from the alcohol and chlorodifluoromethane ia aqueous base, has been iavestigated as an inhalation anesthetic (30,31) as have several ethers made by addition of the alcohol to various fluoroalkenes (32,33). Methacrylate esters of the alcohol are useful as a sheathing material for polymers ia optical appHcations (34). The alcohol has also been reported to be useful as a working fluid ia heat pumps (35). The alcohol is available ia research quantities for ca 6/g (1992). 

N-Acylation is readily carried out by reaction of the alkaU metal salts with the appropriate acid chloride. C-Acylation of pyrroles carrying negative substituents occurs in the presence of Friedel-Crafts catalysts. Pyrrole and alkylpyrroles can be acylated noncatalyticaHy with an acid chloride or an acid anhydride. The formation of trichloromethyl 2-pyrryl ketone [35302-72-8] (20, R = CCI3) is a particularly useful procedure because the ketonic product can be readily converted to the corresponding pyrrolecarboxyUc acid or ester by treatment with aqueous base or alcohoHc base, respectively (31). 

Metal- Working and Hydraulic Fluids. In the preparation of fluids for metal-working and hydrauflcs, the trend has been to replace organic-based materials with aqueous-based materials. Neodecanoic acid has found apphcation in these newer fluids as a corrosion inhibitor and a viscosity improver. For example, neodecanoic acid is used in an aqueous hydrauflc fluid concentrate for corrosion inhibition and improved antiwear properties (101), in the preparation of a thickened aqueous hydrauflc fluid to reduce viscosity loss (102), and in a water-soluble metal working oil to reduce corrosion (103). In a similar vein, neodecanoic acid has been used in antifreeze concentrates for corrosion inhibition (104). 

A review of preparative methods for metal sols (colloidal metal particles) suspended in solution is given. The problems involved with the preparation and stabilization of non-aqueous metal colloidal particles are noted. A new method is described for preparing non-aqueous metal sols based on the clustering of solvated metal atoms (from metal vaporization) in cold organic solvents. Gold-acetone colloidal solutions are discussed in detail, especially their preparation, control of particle size (2-9 nm), electrophoresis measurements, electron microscopy, GC-MS, resistivity, and related studies. Particle stabilization involves both electrostatic and steric mechanisms and these are discussed in comparison with aqueous systems. 

The first interest in the electroreduction of N02 or NO catalyzed by metal complexes is to model the activity of nitrite reductase enzymes.327 There is also an extensive growth in studies related to the development of metal complex-based electrochemical sensors for NO determination in biological and environmental samples 328 329 Nitrate disproportionates to nitric oxide and nitrate in aqueous solution. 

Alkaline nitration with alkoxide bases and nitrate esters was first explored by Endres and Wislicenus who synthesized phenylnitromethane by treating ethyl phenylacetate with potassium ethoxide in ethanol, followed by addition of ethyl nitrate and hydrolysis-decarboxylation of the resulting a-nitroester with aqueous acid. Phenylnitromethane is synthesized in a similar way via alkaline nitration of benzyl cyanide, followed by treatment of the resulting a -nitronitrile with aqueous base. ° Wieland and co-workers used alkali metal alkoxides and nitrate esters for the nitration of cyclic ketones but the yields and purity of product are often poor. ° ... 

Capsur is an aqueous-based solvent system developed specifically for the cleanup of polychlorinated biphenyl (PCB) spills on solid surfaces, including concrete, asphalt, and metal. 

Pentagone is an aqueous-based surface decontamination product developed for the cleanup of pentachlorophenols, creosote, petroleum hydrocarbons, chlorinated hydrocarbons, polynuclear aromatic hydrocarbons, and selected pesticide and herbicide spills. It can be used on concrete, asphalt, or metal and is capable of being applied as a foam, allowing treatment of overhead, vertical, and horizontal surfaces. It has been commercially available since 1993 and has been used in multiple applications. 

Metallic manganese certainly dissolves readily in 1 mol L-1 aqueous acid, as expected, but in aqueous base a coating of insoluble Mn(OH)2 would form immediately, stopping the predicted reaction. In cases such as aluminum [E° for A13+/A1(s) = -1.67 V], the product Al is soluble in alkali as the aluminate ion Al(OH)4+ but not in neutral water, in which the... 

Since the first synthesis of mesoporous materials MCM-41 at Mobile Coporation,1 most work carried out in this area has focused on the preparation, characterization and applications of silica-based compounds. Recently, the synthesis of metal oxide-based mesostructured materials has attracted research attention due to their catalytic, electric, magnetic and optical properties.2 5 Although metal sulfides have found widespread applications as semiconductors, electro-optical materials and catalysts, to just name a few, only a few attempts have been reported on the synthesis of metal sulfide-based mesostructured materials. Thus far, mesostructured tin sulfides have proven to be most synthetically accessible in aqueous solution at ambient temperatures.6-7 Physical property studies showed that such materials may have potential to be used as semiconducting liquid crystals in electro-optical displays and chemical sensing applications. In addition, mesostructured thiogermanates8-10 and zinc sulfide with textured mesoporosity after surfactant removal11 have been prepared under hydrothermal conditions. 

Nanosized metal sulfide powders of Ag2S, CuS, FeS, Ga2S3. In2S3, MnS, NiS, and ZnS were synthesized for use as gas- and liquid-phase mercury sorbents. An aqueous-based synthesis method using the surfactant cetyltrimethylammonium bromide (CTAB) is described. The vapor- and aqueous-phase mercury-sorption characteristics of the nanocrystalline powders synthesized and of commercially produced Ag2S, AU2S. and AU2S3 are presented. 

Stibine. Sbl h, is formed by hydrolysis of some metal antimonides or reduction (with hydrogen produced by addition of zinc and HC1) of antimony compounds, as in the Gutzeit test. It is decomposed by aqueous bases, in contrast with arsine. It reacts with metals at higher temperatures to give the antimonides. The antimonides of elements of group la. 2a, and 3a usually are stoichiometric, with antimony trivalent. With other metals, the binary compounds are essentially intermetallic. with such exceptions as the nickel series, Ni. Sb.. NiSb, Ni5Sb2 and Ni4Sb. 

Methylene Chloride tdichtaromethane). CAS 75-09-2. As with the other members of the methyl series of chlorinated hydrocarbons, methylene chloride can he produced hy direct chlorination of methane. The usual procedure involves a modification of the simple methane process. The product from Ihe first chlorination passes through aqueous zinc chloride, contacting methanol at about 100 C. Thus. HCl from chlorination is used to displace the alcohol group, producing additional methyl chloride. This is further chlorinated to methylene chloride. Methylene chloride reacts violently in the presence of alkali or alkaline earth metals and will hydrolyze to formaldehyde in the presence of an aqueous base. Alkvlalion reactions occur at both functions, thus di-suhstiiulioiis result. For example. 

The parent / -f-butylcalix[n] arenes (n = 4, 6, 8) are almost completely insoluble in water. However, their resemblance to crown ethers and spherands makes them interesting from the point of view of applications as phase transfer catalysts (Section 3.8.2). Table 3.20 shows the selectivity of calixarene 3.118 and its hexameric and octameric homologues for the extraction of various metal hydroxides into an organic receiving phase such as chloroform. Fortunately, in aqueous base the calixarenes are sufficiently soluble to act as phase transfer catalysts as a consequence of deprotonation of one of their phenolic hydroxyl groups. This solubility contrasts to [18] crown-6, which is much more effective in neutral solution. 

Lactams or related cyclic, conformationally fixed amides are more readily N-alkylated than acyclic amides [96], As illustrated by the examples in Scheme 6.23, structurally elaborate alkylating agents can be used to alkylate lactams. During the workup of such reactions it should be kept in mind that four- and six-membered lactams are readily hydrolyzed by aqueous base (Scheme 3.8), and most lactams are also readily hydrolyzed by aqueous acids. Prolonged treatment of lactams with alkali metal hydroxides or acids during the work-up should therefore be avoided. 

Alkoxides, the conjugate bases of alcohols, are prepared from alcohols by reaction with reactive metals or metal hydrides. They are used as organic bases. Because of the greater acidity of phenols, phenoxides can be obtained from phenols and aqueous base. 

The reaction conditions for this type of preparation generally involve nonaqueous solvents, such as tetrahydrofuran (THF) or diethyl ether, and rigorous exclusion of air and water. Some metallocarboranes, however, may be prepared in high yield by reaction of a metal salt and the nido monoanion, C2B9H12-, in strong aqueous base ... 

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