Long-chain amine

Because of the charged nature of many Langmuir films, fairly marked effects of changing the pH of the substrate phase are often observed. An obvious case is that of the fatty-acid monolayers these will be ionized on alkaline substrates, and as a result of the repulsion between the charged polar groups, the film reverts to a gaseous or liquid expanded state at a much lower temperature than does the acid form [121]. Also, the surface potential drops since, as illustrated in Fig. XV-13, the presence of nearby counterions introduces a dipole opposite in orientation to that previously present. A similar situation is found with long-chain amines on acid substrates [122]. 

The long-chain amine can most quickly be reduced to size via the nitrile. 

Inhalation. Long-chain amines are not considered an inhalation hazard at ambient conditions because of their relatively low volatiHty. 

A monolayer of the pyridine-substituted alkyl merocyanine (12) was prepared in the 1970s (67), and a noncentro symmetric multilayer stmcture of merocyanine amphiphiles was later prepared (68) using derivatives, but introducing long-chain amines as the counter layer in an ABABAB system (69,70). 

Alternate-layer LB films (Y-type, ABAB) of long-chain amines and fatty acids maybe used for pyrroelectric appHcations (Fig. 5). Stearylamine, C gH2yNH2, and a series of straight-chain fatty acids, yield a thick film (several hundreds of monolayers) which gave a pyrroelectric coefficient of - 0.05 nC/(cm -K) (72). A coefficient of 0.3 nC/(cm -K) for an 11-monolayer sample of CO-tricosenoic acid and docosylamine C22H4 NH2 has been reported (73). 

An obvious modification of the above procedure will permit the determination of long-chain amines or quaternary ammonium salts (cationic surfactants) ... 

A long-chain amine usually fed to the steam header and employed to prevent steam and condensate line corrosion by a surface-filming... 

Cationic Long-chain amines Emulsifying agents Low or varying water solubility Acid stable... 

Diamines and polyamines Quaternary ammonium salts Polyoxyethylenated long-chain amines Corrosion inhibitor Water-soluble Surface adsorption to silicaeous materials... 

Erickson, J. G. Reactions of Long Chain Amines. V. Reactions with Sugars. 

Some amphoteric softeners such as amino acids (10.237) and sulphobetaines (10.238) are more effective and durable than the nonionic types but less durable than the cationics moreover, they tend to be expensive. Other amphoteric types include the zwitterionic forms of quaternised imidazolines (10.239) long-chain amine oxides (10.240) also exhibit softening properties. 

CFB (1) [Chemische Fabrik Budenheim] A process for removing cadmium from phosphoric acid by extracting with a solution of a long-chain amine in a hydrocarbon. Developed and operated by the German company of that name. 

As to the origins of the major N compounds identified, it is possible that at least a portion of some of these compounds are pyrolysis products of amino acids, peptides, proteins, [18] and porphyrins (a component of chlorophyll), [19] or originate from the microbial decomposition of plant lignins and other phenolics in the presence of ammonia. [20] Of considerable interest are the identifications aromatic and aliphatic nitriles. Nitriles can be formed from amines with the loss of 2 H2, from amides with the loss of H20, and also by reacting n-alkanoic acid with NH3. [21] The detection of long-chain alkyl- and dialkyl-nitriles points to the presence in the soil or SOM of long-chain amines... 

A variation of this method was used to control the surface properties of aluminum oxide particles, particularly the surface density of Lewis acid sites. Instead of using a long-chain amine surfactant, the solution of aluminum alkoxide precursor was mixed with a small amine to convert the alkoxide dimer (or oligomer in general) into monomeric alkoxide-amine adduct. Controlled hydrolysis of this adduct produces an aluminum oxyhydroxide in which the surface A1 ions are coordinated to amine... 

Wennersten found that the extractant system tri- -butylphosphate (TBP) in Shellsol A diluent was temperature dependent with extraction decreasing with increasing temperature. Therefore, extraction from the broth at room temperature (22°C) and water stripping at 60°C provided an efficient process (Fig. 10.9). The extraction with long-chain amines was hampered by the formation of emulsions and thus poor separation. Emulsion formation depended on the diluent with hydrocarbons, e.g., Alamine 336/Shellsol A, given the best separation. 

As noted earlier (see section 12.3.1), the Amex process, which uses long-chain amines, is preferred over the Dapex process, which uses HDEHP, for solvent extraction of uranium from H2SO4 leach solutions. Because the surfactant properties of amine sulfates are conducive to formation of objectionable emulsions, the Amex process is very sensitive to the presence of solids in the H2SO4 leachate. For acceptable phase coalescence in the Amex process, feeds should contain no more than 20 ppm solids. The Dapex process can tolerate feeds containing as much as 100 ppm solids. 

Thus there is considerable incentive to find extractants that could tolerate higher quantities of solids in H2SO4 leach liquors. Stripping of uranium from the Amex process extractant and subsequent regeneration of the amine solvent also consume considerable quantities of acid and base. Recovery of uranium from H2SO4 solutions would be simplified if a convenient neutral extractant could be found. An extractant with better selectivity for vanadium and molybdenum than HDEHP and long-chain amines is also desirable. 

Formation of trimetaphosphate anions from those of Graham s salt also occurs in solution. In water this process is not associated with hydrolytic cleavage of the P—0—P bonds, as was at first assumed (10, 322), but is independent of it (361). Thus polyphosphates of long-chain amines which are soluble in benzene form trimetaphosphate quantitatively on warming the anhydrous solution (359). This transformation follows Ostwald s rule for successive transformations, since trimetaphosphates are more stable than polyphosphates (322). 

The final class of water-soluble synthetic detergents derived from petroleum are the cationics. These products, when ionized, have the hydrophobic portion of the molecule in the cation. They are of interest principally because of the bactericidal properties they exhibit. Their performance as detergents is poor. The principal products marketed to date have been derived from normal long-chain amines, but procedures for their preparation from petroleum hydrocarbons (1) have been described as follows ... 

Primary amines can be dehydrogenated under mild conditions and in high yields to nitriles at the nickel hydroxide electrode (Eq. (9)). Short chain and reactive amines are already oxidized at 5 °C, whilst long chain amines need somewhat higher temperatures. Diamines are converted smoothly to dinitriles (Table 13). 

According to Glazer and Dogan s data, the ammonium groups pK should have been ca. 11.5. However, the pK of the SDS-BSA surface complex had a value of ca. 8.5. Shifts in pK of this order of magnitude—i.e., 3 pH units—have been observed in titrations of monomolecular films of long-chain amines (5). The explanation offered for the shift in apparent... 

The shift in apparent pK of the SDC-BSA film may result from the formation of a surface film with structural characteristics strongly analogous to a monolayer of a long chain amine. The required characteristics would be formation of a surface structure which would lead to a high density of charged groups immersed in the aqueous phase, and formation of a bond which permits the bonding partners to retain their identities— e.g., an ion pair. 

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