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Organic acids, basic

With charged compounds (weak acids or bases), the adjustment of the pH of the aqueous mobile phase has the strongest influence on the change in selectivity of a chromatographic separation. This is due to the fact that organic acids, basic compounds, and hybrid ionic compounds (zwitterions) show very different behavior in response to pH variations of the eluent [7-9]. [Pg.647]

The latter technique is particularly effective if organic acid, basic, or amphoteric compounds are present. If emulsions occur, centrifugation may be employed (but only for nonflammable solvents). [Pg.8]

In the former, it gives precipitates with halides (except the fluoride), cyanides, thiocyanates, chromates(VI), phosphate(V), and most ions of organic acids. The silver salts of organic acids are obtained as white precipitates on adding silver nitrate to a neutral solution of the acid. These silver salts on ignition leave silver. When this reaction is carried out quantitatively, it provides a means of determining the basicity of the acid... [Pg.430]

Dowex 1-X4 1.0 0.70 Strongly basic anion exchanger with S-DVB matrix for separation of organic acids, nucleotides, phosphoinositides, and other anions. Molecular weight exclusion is <1400. [Pg.1110]

The process of reabsorption depends on the HpophiHc—hydrophiHc balance of the molecule. Charged and ioni2ed molecules are reabsorbed slowly or not at all. Reabsorption of acidic and basic metaboHtes is pH-dependent, an important property in detoxification processes in dmg poisoning. Both passive and active carrier-mediated mechanisms contribute to tubular dmg reabsorption. The process of active tubular secretion handles a number of organic anions and cations, including uric acid, histamine, and choline. Dmg metaboHtes such as glucuronides and organic acids such as penicillin are handled by this process. [Pg.270]

Whereas metal salts of carboxyUc acids cataly2e the above reactions, these are not sufftciendy basic to cleave Si—H bonds. Mercury salts of organic acids in the presence of silver perchlorate, however, do react to produce organoacyloxysdanes (111). [Pg.27]

Carbonates. Basic zirconium carbonate [37356-18-6] is produced in a two-step process in which zirconium is precipitated as a basic sulfate from an oxychloride solution. The carbonate is formed by an exchange reaction between a water slurry of basic zirconium sulfate and sodium carbonate or ammonium carbonate at 80°C (203). The particulate product is easily filtered. Freshly precipitated zirconium hydroxide, dispersed in water under carbon dioxide in a pressure vessel at ca 200—300 kPa (2—3 atm), absorbs carbon dioxide to form the basic zirconium carbonate (204). Washed free of other anions, it can be dissolved in organic acids such as lactic, acetic, citric, oxaUc, and tartaric to form zirconium oxy salts of these acids. [Pg.437]

Oxalate Acid Number. A metal soap solution is treated with a measured excess of organic acid. Potassium oxalate solution is added to precipitate the metal and the total sample is back-titrated with alkaU to determine its acidity. Acidity is expressed ia acid number units, equivalent to mg KOH per g. A neutral soap gives a 2ero acid number, an acidic soap solution a positive acid number, and a basic soap solution a negative acid number. [Pg.220]

In the hands of Collie and Tickle in 1899 this reaction gave the first crystalline pyrylium salts. The salt character of the compounds was proved by conductivity measurements the basicity of 2,6-dimethylpyrone was found to be a little higher than that of urea. Basicities of other pyrones decrease in the order 2,6-dimethyl-> 2-phenyl-6-methyl-> 2,6-diphenylpyrone, paralleling the dipole moments. These hydroxypyrylium salts hydrolyze in water to pyrones. " The formation of salts of 2,6-dimethylpyrone with organic acids was investigated by Kendall,and with mineral acids by Cook. 11 ... [Pg.255]

Lubricating oils Bearings do not normally fail due to corrosion, but where this has occurred it has been associated with the acidity of white oils, the peroxide content and the presence of air. Peroxides are the controlling factor, but corrosion is reduced in the absence of air. The corrosion product consists of a basic lead salt of two or more organic acids " see Section 2.11). [Pg.733]

Most organic substances can be dissolved readily in a suitable organic solvent and some are directly soluble in water or can be dissolved in aqueous solutions of acids (basic materials) or of alkalis (acidic materials). Many inorganic substances can be dissolved directly in water or in dilute acids, but materials such as minerals, refractories, and alloys must usually be treated with a variety of reagents in order to discover a suitable solvent in such cases the preliminary qualitative analysis will have revealed the best procedure to adopt. Each case must be considered on its merits no attempt at generalisation will therefore be made. It is however of value to discuss the experimental technique of the simple process of solution of a sample in water or in acids, and also the method of treatment of insoluble substances. [Pg.110]

All chemicals, whether inorganic or organic, are either acidic, basic, or neutral. An example of an inorganic acid is sulfuric acid used in automobile batteries, while the acetic acid found in vinegar is an organic acid. Ammonia found in many household cleaners is a base, as are sodium carbonate and sodium hydroxide (lye). Sodium chloride (common salt) is an example of a salt because it is produced by the neutralization of hydrochloric acid with sodium hydroxide. A solution of table sugar in water is neutral (pH 7) because it does not contain hydrogen ions nor does it react with bases to produce water. [Pg.14]

The amino acids, basic building blocks of proteins, all share this dual acid-base character. See Chapter 13 for a description of the amino acids and their biological chemistry. Organic bases also have a long and varied history as painkillers and narcotics, as our Chemishy and Life Box on the next page describes. [Pg.1235]

Complexes of tetravalent zirconium and ligands selected from organic acids such as citric, tartaric, malic, and lactic acid and a complex of aluminum and citric acid are suitable as dispersants [288-291]. This type of dispersant is especially useful in dispersing bentonite suspensions. The muds can be used at pH values ranging from slightly acidic to strongly basic. [Pg.311]

If the analyte contains either an acidic or a basic functionality, adjusting the pH of the extraction solvent to make the analyte either ionic or nonionic may be advantageous. To make an analyte that contains an acidic or basic functionality nonionic for extraction into a nonpolar solvent, a small amount (5% or less) of an organic acid (such as acetic acid or trifluoroacetic acid) or organic base (triethylamine) along with methanol (about 10%) can be added to diethyl ether or ethyl acetate. Conversely, buffered solutions can be used to control the pH precisely in such a way as to control the charge on an analyte and thus improve its extraction efficiency into polar solvents. [Pg.305]


See other pages where Organic acids, basic is mentioned: [Pg.20]    [Pg.27]    [Pg.147]    [Pg.363]    [Pg.180]    [Pg.438]    [Pg.84]    [Pg.30]    [Pg.238]    [Pg.139]    [Pg.372]    [Pg.22]    [Pg.139]    [Pg.427]    [Pg.43]    [Pg.122]    [Pg.1213]    [Pg.109]    [Pg.452]    [Pg.733]    [Pg.618]    [Pg.279]    [Pg.339]    [Pg.917]    [Pg.65]    [Pg.260]    [Pg.332]    [Pg.338]    [Pg.363]    [Pg.875]    [Pg.735]    [Pg.63]    [Pg.392]    [Pg.713]   
See also in sourсe #XX -- [ Pg.5 ]




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