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Polybasic Compounds

Consider, as the simplest example, the interaction of a base B1B2 which has two binding sites, Bi and B2, with a Lewis acid A which has a single binding site. Two 1 1 complexes can be formed by the interaction of the Lewis acid at either of the sites Bi or B2, giving the isomeric 1 1 complexes Ci (A-B1B2) and C2 (B1B2-A) of equilibrium [Pg.38]

A 1 2 (1 Base 2 Acids) complex may be formed by the addition of a second Lewis acid to either of the 1 1 complexes. This possibility can be ruled out if the concentration of base is chosen in large excess to the concentration of the acid. [Pg.39]

Most experimental methods are not able to determine the equilibrium concentrations [Cl] and [C2] separately and furnish only the sum [Ci] + [C2]. It follows that experimental methods yield only the total (or gross) equilibrium constant Ky. [Pg.39]

Three cases are encountered for the determination of the various AT,s all sites have the same basicity, one site is significantly more basic than the other(s) and more than one site contributes significantly to the total constant. [Pg.39]

If all sites have the same basicity, then = nKi and each individual constant is [Pg.39]


Drugs may also have more than two pKa values, such as polyprotic or polybasic compounds (e.g., minocycline), and such drugs exhibit a complex pH solubility profile. It is essential to know per se pH of the drug solution during preformulation studies. The pH is measured or theoretically calculated if the pKa and drug concentration C are known. The pH of a weak acid or the salt of a weak base and a strong acid can be calculated using the equation... [Pg.953]

L-Amino acid oxidase of rat kidney appears to catalyze the same type of reaction as n-amino acid oxidase. It oxidizes the monoamino, mono-carboxylic acids, but does not attack either dicarboxylic or polybasic compounds. Proline and W-methylamino adds are oxidized. A unique property of this enzyme is its ability to oxidize hydroxy acids. Only L-hydroxy acids are attacked. The ratio of hydroxy acid oxidation rate to amino acid rate is constant throughout purification. In general, hydroxy acid oxidation proceeds somewhat more rapidly than amino add oxidation, and the hydroxy acids corresponding to the basic amino adds... [Pg.292]

Phthalanilides and Related Polybasic Compounds - Studies with 2-chloro-4, 4"-bis(2-imidazolin-2-yl)terephthalanilide, one of a series of compounds highly active against leukemia L1210, was shown to completely... [Pg.154]

Fig. 9 illustrates another aspect of the dose-response relationship the significance of the amount of polycations present per cell. These experiments, performed by varying the concentrations of both polycation and cells, show that the yield of infectious centers is determined primarily by the polycation ceU ratio rather than the absolute concentration of the polybasic compound. The important practical implication of these data is that an appropriate adjustment in the polycation concentration must be made to obtain an optimal infection by viral RNA at a given ceU concentration. [Pg.106]

Possible uses for these polyhydroxy compounds include the preparation of alkyd-type resins with polybasic acids, the formation of ester plasticizers, and the preparation of surface-active agents. [Pg.432]

Reaction of polyhydroxy compounds with polybasic acids gives rise to condensation polymers containing ester (—COO—) groups. Because of the presence of these groups such polycondensates are known as polyesters and find use in such diverse applications as fibres, surface coatings, plasticisers, rubbers and laminating resins. These materials are discussed in detail in Chapter 25. [Pg.556]

Condensation of polyhydroxy compounds with polybasic acids, e.g. a glycol with a dicarboxylic acid ... [Pg.694]

In order to co clarify the role of complex formation, the new data on stability constants should be accumulated, being collected at strictly similar conditions. It should be also mentioned that any analysis of equilibrium in solutions involving anions of polybasic hydroxy carboxylic acids requires the data on the deprotonation constants of the acid in question. This information would be crucial for conclusions regarding the presence and stability of mixed complexes in the system. Valuable knowledge about the structure of complex compounds present in solutions (and in precursors as well, see later) may be gained by means of vibrational spectroscopy (IR and Raman spectra) and nuclear magnetic resonance. [Pg.505]

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... [Pg.1052]

Moreover, many hydrogen compounds, when dissolved in such solvents, ionize more or less completely lo give solvated protons and anions, In the case uf polybasic acids, ionization constants are reported for each step in this dissociation. [Pg.799]

The lower members Polybasic acids and Acids. Phenols. Primary amines. Unsaturated Saturated aliphatic Nitro compounds... [Pg.1202]

The term alkyd resins represents a broad class of compounds commonly used in coatings and is a particular type of polyester formed by the reaction of polyhydric alcohols and polybasic acids. [Pg.36]

Because of the polyfunctional character of aconitic acid, it being both an unsaturated acid and a polybasic acid, the compound can undergo a variety of chemical reactions. Application of derivatives obtained by such reactions has aroused considerable interest in the plasticizer, wetting agent and resin manufacturing fields. [Pg.244]

The last case illustrates the complicated behavior possible if both intra- and intermolecular H bonding are present. Such combinations, called mixed association by Lutskil (1274), are common among compounds with several proton donor and acceptor groups. Forecasting which type will dominate is difficult. Other examples besides the phos-phonic acids are dihydroxy, hydroxy, or amino acids, and polybasic acids. [Pg.183]

Alkyd resins have been the workhorse for the coatings industry over the last half century. The term alkyd was coined to define the reaction product of polyhydric alcohols and polybasic acids, in other words, polyesters. However, its definition has been narrowed to include only those polyesters containing monobasic acids, usually long-chain fatty acids. Thus thermoplastic polyesters typified by polyethylene terephthalate (PET) used in synthetic fibers, films, and plastics and unsaturated polyesters typified by the condensation product of glycols and unsaturated dibasic acids (which are widely used in conjunction with vinylic monomers in making sheet molding compounds or other thermosetting molded plastics) are not considered as part of the alkyd family and are beyond the scope of the present discussion. [Pg.3297]

Miescher had been handicapped by the difficulty of isolating nuclein in amounts adequate for further study, but he now turned his attention to the nuclear material from a source readily accessible in Basel—the ripe spermatozoa of the salmon. He discovered that this nuclein is a compound of a polybasic organic acid with a basic substance. In 1889, Altmann introduced the term nucleic acid to describe the acidic constituent, and furnished a general method for its isolation. [Pg.194]

Salts of mineral acids (particularly polybasic acids), phenols, and tannins will coagulate solutions of methylcellulose, although this can be prevented by the addition of ethanol (95%) or glycol diacetate. Complexation of methylcellulose occurs with highly surface-active compounds such as tetracaine and dibutoline sulfate. [Pg.464]


See other pages where Polybasic Compounds is mentioned: [Pg.276]    [Pg.276]    [Pg.188]    [Pg.82]    [Pg.38]    [Pg.276]    [Pg.276]    [Pg.188]    [Pg.82]    [Pg.38]    [Pg.1045]    [Pg.31]    [Pg.38]    [Pg.585]    [Pg.5]    [Pg.298]    [Pg.299]    [Pg.325]    [Pg.4]    [Pg.875]    [Pg.1045]    [Pg.243]    [Pg.13]    [Pg.124]    [Pg.199]    [Pg.565]    [Pg.106]    [Pg.263]    [Pg.3394]    [Pg.47]    [Pg.3314]    [Pg.124]    [Pg.83]   


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