Short-chain amines

Figure 5 Intercalation of hydrophobic short-chain amines into a-ZrP to widen the gallery spacings and substitution of these by small organic cations.

Pigment and filters Poly substituted phenol ethoxylates Phosphate esters Short chain amine EO/PO co-polymers Lignin sulphonates Wetters and dispersants... 

Agren, P. et al., Kinetics of cosurfactant-surfactant-silicate phase behavior. 2. Short-chain amines, Langmuir, 16, 8809, 2000. 

Long-chain alkanoic acids have a limited use as surfactants. They are very weak acids having a pH range between 5 and 6. They are soluble in most organic solvents but purely soluble in water. Alkali metals and short-chain amines as counterions yield water-soluble soaps which, as a result of hydrolysis, form with free acids the dispersible 1 1 or 1 2 association complexes, so-called "acid soaps". 

Asquith [71] has demonstrated that, with short-chain amines like ethyl or n-butyl amine in the presence of wool liber in alkali, the amounts of lan-thionine and lysinoalanine are less (compared to alkali alone), but these two species are still produced in detectable quantities. However, longer-chain amines like pentyl amine react quantitatively with wool fiber, and virtually no lanthionine or lysinoalanine is formed. 

Tables 10.2 and 10.3 lists the physical properties of the aliphatic amines. The lowest molecular weight amine, ethylamine, boils at only 16.6 C and is thus available only as a compressed gas or as an aqueous solution. The other fifteen aliphatic amines have boiling points in the range of 32.4-213 C. The flash points of these amines are low with the highest being only 70 F for the tributylamine. These short-chain amines are readily soluble in water and most organic solvents. The solubility of amines decreases with increasing temperature, for example, triethylamine is completely soluble in water below 18 C but is only partially soluble above this temperature. The lower alkylamines have the characteristic ammonia odor which decreases with increased substitution onto the nitrogen atom.

FIGURE 4 Intercalation of short-chain amines to increase the a-ZrP gallery height. 

Free fatty acids are not used as surfactants, due to their low solubility in water. However water-soluble fatty acid salts show good water affinity and are widely used, especially the alkaline ones and those resulting from neutralization with short-chain amines (ethanol amine, diethanol amine, triethanol amine). 

Flotation. Tallow amines contain small amounts of short-chain compounds, eg, the octyl, lauryl, and myristyl (C ) groups. These amines usually produce enough froth for the flotation. Small quantities of specialized synthetic alcohols, eg, Dowfroth P, are frequentiy added to the flotation system to supplement the natural frothers. The quantities of the reagents used ia potash flotation plants are Hsted ia Table 5. 

Only a few commercial uses for TDA per se have been found. In epoxy curing appHcations, 2,4- I DA has been used as a component of a eutectic mixture with short chain aUphatic glycidal ether resins (46) as well as by itself (46,47) TDA (46) and single isomers (47) are also used as amine curatives. TDA can be used as a chain extender in polyurethanes (48,49). TDA is cited as a monomer in making aromatic polymers with unique properties, eg, amorphous polyamides (50), powdered polyamides (51), and low melting, whoUy aromatic polyamides (52). 

Thiuram Sulfides. These compounds, (8) and (9), are an important class of accelerator. Thiurams are produced by the oxidation of sodium dithiocarbamates. The di- and polysulfides can donate one or more atoms of sulfur from their molecular stmcture for vulcanization. The use of these compounds at relatively high levels with litde or no elemental sulfur provides articles with improved heat resistance. The short-chain (methyl and ethyl) thiurams and dithiocarbamates ate priced 2/kg. Producers have introduced ultra-accelerators based on longer-chain and branched-chain amines that are less volatile and less toxic. This development is also motivated by a desire to rninirnize airborne nitrosamines. 

For sufficient retention of these very polar sulfonated carboxylates on RP columns, the addition of an ion-pairing (IP) agent such as tetraethylammonium acetate (TEAA) to the LC buffer was compulsory [13]. To maintain the compatibility of the eluent with the MS interface, the use of such an involatile cationic additive entailed a cation exchanger to be placed between the column and the interface [13]. Alternatively, equimolar amounts (5 mM) of acetic acid and triethyl-amine, which form the volatile IP agent triethylammonium, were added to the mobile phase in order to improve the retardation of very polar SPC [14]. While the first approach with TEAA was effective in retaining even the very short-chain C3- and C4-SPC (Fig. 2.10.4), the weaker IP agent triethylammonium notably increased the retention of C5-SPC and higher, whereas C4-SPC elutes almost with the dead volume of the LC (Fig. 2.10.5). Addition of commonly used ammonium acetate as buffer component led to the co-elution of the short-chain SPC ([Pg.322]

As expected, LC separation of the dichloromethane/acetone SPE eluate in the RP-mode, presented as FIA-APCI-MS(+) in Fig. 2.12.13, was impossible because the alkyl ethoxy amines as cationic surfactants could not be eluted under conventional RP-separation conditions [37, 53]. The use of methane sulfonic acid for ion-pairing resulted in the separation of the compounds in the methanol eluate as shown as TIC (d) and selected ion trace masses (m/z 504 (a), 670 (b), and 802 (c)) in Fig. 2.12.14. Here, the short-chain ethoxy amines were eluted later than the more polar long-chain homologues [39]. 

MAO Inhibitors. MAO is an enzyme which oxidizes a variety of monoamines. Among the substrates of this enzyme are tyramine, tryptamine, 5-hydroxytryptamine, histamine, and short chain aliphatic monoamines ( ). Oxidation of histamine to imidazoleacetaldehyde can be carried out by DAO as well as MAO. is also responsible for the conversion of N -MH, the product of HMT, to N -MIAA. Many MAO inhibitors have been identified they are conventionally divided into hydrazides, hydrazines and amines (44). Some MAO inhibitors, e.g. the hydrazines, are non-selective they also inhibit DAO. 

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). 

Dave (12) and Supina (6) have compared the properties of the two series these references are useful in selection of the appropriate porous polymer for a specific separation. The porous polymers are useful for analysis of permanent gases and for short chain polar compounds such as glycols, acids, amines. Water is eluted as a symmetrical peak with these materials. It is important to note that for most polar compounds such as acids or amines, it is desirable to use glass columns rather than metal. 

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