Anion active substances

As mentioned, AOS is a complex mixture of anionic active substances the nature of which is dependent on the quality of the olefin feed and the manufacturing processes employed. Formulations utilizing AOS are developed according to the level and type of these active species. Analytical procedures are therefore required to define their level and nature. 

Anionic-active substances are incompatible with strong acids (pH < 4) because the hydrophihcity of the acid group will decrease due to lower dissociation. There is also the risk of insoluble ion pairs when anionic-active substances are combined with cationic-active ones such as neomycin sulfate. 

In presence of polyamines the maximum of light absorption of indicated triphenylmethane dyes displaces on 10-30 nm, for azo dyes the shift of the band reaches 50-80 nm. The greatest difference of light absorption of associates and reagents is watched for BKM at pH 5,05, for BPR at pH 4,20, for CPR in an interval pH 5,05-5,45. At these pH dyes are anions, it promotes interaction with a cationic surface-active substance. The ratios between polymer and BKM, BPR, CPR are established by spectroscopy method, its equal 1 20, 1 20 and 1 30 accordingly. 

The perspective of using consecutive reactions is grounded on the example of the analysis of isomeric mono-nitrophenols and anion surface-active substances. The variants of systematic analysis of mixtures of tri-, di- and mono-nitrophenols, anion surface-active substances, based on the combination of measurements of consecutively received extracts at different pH values are discussed. 

Active fractions are combined and concentrated in vacuo to about 5 liters. The concentrate is then adjusted to a pH of 8.0 with 6N sulfuric acid and passed through a column packed with 1 liter of an anion exchange resin, Dowex 1X2 (OH form). The column is washed with about 5 liters of water and the effluent and the washings containing active substance are combined and are concentrated to 1/15 by volume. The concentrate is adjusted to a pH of 10.5 with 6N sodium hydroxide and 5 volumes of acetone is added thereto. The resultant precipitate is removed by filtration and the filtrate is concentrated to 500 ml. The concentrate is adjusted to a pH of 4.5 with 6N sulfuric acid and 2.5 liters of methanol is added thereto. After cooling, a white precipitate Is obtained. The precipitate is separated by filtration and washed with methanol. After drying in vacuo, about 300 g of white powder is obtained. 

Active matter (anionic surfactant) in AOS consists of alkene- and hydroxy-alkanemonosulfonates, as well as small amounts of disulfonates. Active matter (AM) content is usually expressed as milliequivalents per 100 grams, or as weight percent. Three methods are available for the determination of AM in AOS calculation by difference, the two-phase titration such as methylene blue-active substances (MBAS) and by potentiometric titration with cationic. The calculation method has a number of inherent error factors. The two-phase titration methods may not be completely quantitative and can yield values differing by several percent from those obtained from the total sulfur content. These methods employ trichloromethane, the effects from which the analyst must be protected. The best method for routine use is probably the potentiometric titration method but this requires the availability of more expensive equipment. 

The purification of some enzymes inactivates them because substances essential for their activity but not classed as a prosthetic group are removed. These are frequently inorganic ions which are not explicit participants in the reaction. Anionic activation seems to be non-specific and different anions are often effective. Amylase (EC 3.2.1.1), for example, is activated by a variety of anions, notably chloride. Cationic activation is more specific, e.g. magnesium is particularly important in reactions involving ATP and ADP as substrates. In cationic activation it seems very likely that the cation binds initially to the substrate rather than to the enzyme. 

Lipophilicity. The gross lipophilicity of the ligand and of its complexes plays a very important role whenever substances soluble in organic media of low polarity are needed. This is the case in studies of anion activation and of cation transport through lipid membranes, where salts have to be dissolved in organic phases. The lipophilic character may be controlled via the nature of the hydrocarbon residues forming the ligand framework or attached to it. 

The most universal transport systems are those involved in the transport of the ubiquitous inorganic ions, sodium, potassium and calcium1. The sodium pump counteracts passive water movement across the cell membrane by removing sodium ions together with chloride or other anions from the cytoplasm to lower its content of osmotically active substances. In most cells, however, the elimination of sodium ions is connected with an accumulation of potassium ions6. For three sodium ions leaving the cell two potassium ions are taken up9,10). The resulting concentration... 

Active anticorrosive pigments inhibit one or both of the two electrochemical partial reactions. The protective action is located at the interface between the substrate and the primer. Water that has diffused into the binder dissolves soluble anticorrosive components (e.g., phosphate, borate, or organic anions) out of the pigments and transports them to the metal surface where they react and stop corrosion. The oxide film already present on the iron is thereby strengthened and sometimes chemically modified. Any damaged areas are repaired with the aid of the active substance. Inhibition by formation of a protective film is the most important mode of action of the commoner anticorrosive pigments. 

LAS Treatability and Environmental Concentrations. The removal of LAS during sewage treatment was confirmed by monitoring studies in both the United States and Europe. Numerous studies reported anionic surfactant concentrations in surface waters measured by nonspecific analytical techniques such as methylene blue active substance (MBAS). However, the correlation between MBAS and LAS concentrations determined by spe-... 

Such anionic surfactants that form ion pairs with methylene blue and that are extractable with chloroform are known as Methylene Blue Active Substances (MBAS). Other cationic dyes, such as crystal violet dye, may be used instead of methylene blue. Extraction of such an ion-pair complex into benzene has been reported (Hach, 1989). Detection Limit = 10 pg/L. 

More recently, a new series of water dispersed anionic polymers, the AQ 29D, 38D and 55D polymers were released by Eastman Kodak. Since that time, these polymers were used as electrode modifier (12, 13), as covering membrane (14) and as support for enzyme immobilization (15, 16). AQ polymers are high molecular weights (14,000 to 16,000 Da) sulfonated polyester type polymers (17, 18). Their possible structures have been recently presented (18). The AQ polymer serie shows many interesting characteristics useful for the fabrication of biosensors. They are water dispersed polymers and thus compatible with enzymatic activity. They have sulfonated pendant groups similar to Nafion and they can act as a membrane barrier for anionic interferring substances and they offer the possibility to immobilize redox mediators by ion exchange. 

Silicone is used to suppress foam or to preventing foam in aqueous solutions of anionic and nonionic surface-active substances. 

The second group of activators are substances which react with the lactam or its anion to yield an A -substituted lactam [107, 113—116] in a sufficiently fast reaction e.g., isocyanates, anhydrides, esters, ketenimines. The activating effect of Af-substituted lactams was found to incresise with increasing electronegativity of substituents [84, 111, 117]. Another group of activating substances are precursors of compounds of the second group. For example, AT-2,2-trisubstituted j3-oxoamides [118—120] decompose at elevated temperatures very easily into ketone and isocyanate, which is a very effective activator. 

In these titrations,a cationic (Q ) or anionic (X ) species is titrated with an oppositely charged titrant (X or Q ), respectivelly. If the substance determined or the titrant (or both) has adequate lipophilic character, the poorly soluble ionpair precipitates, + X = QX. Further, the same ion pairs can be used as active substances for liquid membrane-type electrodes because of their good extractability into... 

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