Carbon acids, also

Quaternary salts (90) from azalenes obtained from heterocyclic bases and phenacyl halides or derivatives of a-halo carbon acids also contain an acidic exocyclic CH2 group. Therefore, during the deprotonation, mixtures of pseudoazulenes 91 and ylides 98 can be formed, especially if Y = CH. °5 Quaternary salts (90) containing one pyrrole-type nitrogen (Y = N) de-protonate exclusively to pseudoazulenes166 (Scheme 6). Analogous behavior... 

Reactions of 02 with esters and halogenides of carbonic acids also pass nucleophilic substitution as an initial step (Sawyer Gibian 1979). Final products are acyl peroxides or carbonic acids, Scheme 1-79 ... 

Isoamyl Alcohol. — The amyl alcohol produced during fermentation was likewise exposed by Elbs and Brunner to the anodic current action in sulphuric-acid solution. It is converted into isovaleric acid with a current yield of about 80%. Some carbonic acid also formed, but isovaleric aldehyde was not present under the chosen conditions. 

Oxybutyric Acid (CH3-CH(OH)-CH2-COOH).—From this acid were obtained in the positive electrolyte crotonic aldehyde and a little formic acid, also resinous substances. Considerable quantities of carbonic acid, also a little carbon monoxide and unsaturated hydrocarbons, are formed. The small quantities... 

The adsorbed carbonic acid also affects the separations. Figure 8.3A shows the separation of four carboxylic acids after equilibration of the column with 5% 1-butanol eluent Then the column was re-equilibrated with eluent that was freed of carbonic acid by placing an anion-exchange column in the hydroxide form in-... 

In the case of surface corrosion or pitting corrosion not microcolonies but biofilms are involved (Kunzel, 1991). Under oxygen deprivation in the biofilm, fermentative processes take place and carbonic acids (also complexing agents) are formed. Also, sulfate reduction occurs (H2S evolution). These processes cause acid corrosion as well as attack by hydrogen sulfide. In the reaction of HjS with iron(II) ions, iron sulfide is formed, and this speeds up/accelerates the oxygen corrosion (cathodic reaction) Cough-ton et al., 1988). These processes are presented in Fig. 4-6. 

Investigations with hydrochloric acid confirm the influence of proton concentration. Below an acid concentration of 3 N, the rate of hydrolysis is barely influenced, but it increases rapidly when the concentration increases above 3 N. Because of the low dielectric constant of PET (< 4), it is assumed that the acid is only marginally dissociated in the plastic. Organic acids, e.g., adipic acid, also catalyze hydrolysis in PET. Terminal carboxyl groups of the polyester, contributing to all reactions characteristic of carbonic acids, also act catalytically. 

Nylon A class of synthetic fibres and plastics, polyamides. Manufactured by condensation polymerization of ct, oj-aminomonocarboxylic acids or of aliphatic diamines with aliphatic dicarboxylic acids. Also rormed specifically, e.g. from caprolactam. The different Nylons are identified by reference to the carbon numbers of the diacid and diamine (e.g. Nylon 66 is from hexamethylene diamine and adipic acid). Thermoplastic materials with high m.p., insolubility, toughness, impact resistance, low friction. Used in monofilaments, textiles, cables, insulation and in packing materials. U.S. production 1983 11 megatonnes. 

Protonated and diprotonated carbonic acid and carbon dioxide may also have implications in biological carboxylation processes. Although behavior in highly acidic solvent systems cannot be extrapolated to in vivo conditions, related multidentate interactions at enzymatic sites are possible. 

Resorcinol carboxylation with carbon dioxide leads to a mixture of 2,4-dihydroxyben2oic acid [89-86-1] (26) and 2,6-dihydroxyben2oic acid [303-07-1] (27) (116). The condensation of resorcinol with chloroform under basic conditions, in the presence of cyclodextrins, leads exclusively to 2,4-dihydroxyben2aldehyde [95-01-2] (28) (117). Finally, the synthesis of l,3-bis(2-hydroxyethoxy)ben2ene [102-40-9] (29) has been described with ethylene glycol carbonate in basic medium (118), in the presence of phosphines (119). Ethylene oxide, instead of ethyl glycol carbonate, can also be used (120). 

Niobium Pent chloride. Niobium pentachloride can be prepared in a variety of ways but most easily by direct chlorination of niobium metal. The reaction takes place at 300—350°C. Chlorination of a niobium pentoxide—carbon mixture also yields the pentachloride however, generally the latter is contaminated with niobium oxide trichloride. The pentachloride is a lemon-yeUow crystalline soHd that melts to a red-orange Hquid and hydrolyzes readily to hydrochloric acid and niobic acid. It is soluble in concentrated hydrochloric and sulfuric acids, sulfur monochloride, and many organic solvents. 

The hydrogen ion flux that is provided by carbonic acid dissociation also can attack calcite (CaCO ) ... 

Carbamic acid is the monoamide of carbonic acid the diamide is the weU-known compound urea [57-13-6] also called carbamide (see Urea). Guanidine [113-00-8] could be regarded as the amidine of carbamic acid (see Cyanamides). 

Carbon brick and block ate used to line the cupola well (73) or cmcible. When properly installed and cooled carbon linings last for many months or even years of intermittent operation. Their resistance to molten iron and both acid and basic slags provides not only insurance against breakouts but also operational flexibility to produce different iron grades without the necessity of changing refractories. Carbon is also widely used for the tap hole blocks, breast blocks, slagging troughs, and dams. 

The reaction of phosgene (carbonic dichloride [75-44-5]) with alcohols gives two classes of compounds, carbonic esters and carbonochloridic esters, commonly referred to as carbonates and chloroformates. The carbonic acid esters (carbonates), R0C(0)0R, are the diesters of carbonic acid [463-79-6]. The carbonochloridic esters, also referred to as chloroformates or chlorocarbonates, C1C(0)0R, are esters of hypothetical chloroformic acid [463-73-0] CICOOH. 

Because the solution is capable of absorbing one mole of carbon monoxide per mole of cuprous ion, it is desirable to maximize the copper content of the solution. The ammonia not only complexes with the cuprous ion to permit absorption but also increases the copper solubiUty and thereby permits an even greater carbon monoxide absorption capacity. The ammonia concentration is set by a balance between ammonia vapor pressure and solution acidity. Weak organic acids, eg, formic, acetic, and carbonic acid, are used because they are relatively noncorrosive and inexpensive. A typical formic acid... 

A further quantity can be recovered by concentrating the mother liquor. The residue of decolorizing carbon is also likely to contain an appreciable proportion of trimethylgallic acid, which can be extracted by boiling it with the mother liquor. 

Amino-4,6-dimethyl-3-oxo-3//-phenoxazine-l,9-dicarboxylic acid also named actinocin is the chromophor of the red antineoplastic chromopeptide aetinomyein D (formula A). Two cyclopenta-peptide lactone rings (amino acids L-threonine, D-valine, L-proline, sarcosine, and 7V-methyl-L-valine) are attached to the carboxy carbons of actinocin by two amide bonds involving the amino groups of threonine. 

Carothers also produced a number of aliphatic linear polyesters but these did not fulfil his requirements for a fibre-forming polymer which were eventually met by the polyamide, nylon 66. As a consequence the polyesters were discarded by Carothers. However, in 1941 Whinfield and Dickson working at the Calico Printers Association in England announced the discovery of a fibre from poly(ethylene terephthalate). Prompted by the success of such a polymer, Farbenfabriken Bayer initiated a programme in search of other useful polymers containing aromatic rings in the main chain. Carbonic acid derivatives were reacted with many dihydroxy compounds and one of these, bis-phenol A, produced a polymer of immediate promise. 

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