Metal amine salts

A comprehensive screening study to identify optimal release thermodynamics should include both mixed metal amine salts as well as low concentration dopants. It is, however, not practically possible due to the large number of possible combinations. Limiting the potential elements to 3d and 4d transition metals, alkali, alkaline earth metals, and halides down to the sixth period of the periodic table, the number of candidate structures with just two different cations and two different anions in a super cell of 8 formula units is almost 2 million. An intelligent screening method is therefore needed to cut down the number of calculations e.g., a genetic algorithm. 

As outlined in section 18.2, the atomic structure should, in principle, be the correct ground state structure in order to get quantitative correct thermodynamic data from DFT. This is typically only achieved after rigorous computational optimization, which is too computationally costly in any screening study, and we thus have to use model structures that give correct trends but not necessarily exact numbers. This has previously been shown to be a vahd approach for metal chloride amines and other coordination compounds [19,101]. Here, the model structures are based on the different coordination observed in metal amine salts, starting with 8 in SrCU and moving to 6 in MgCl2, and 4 in LiBr if the former is not stable. 

In preparing an aqueous sol ution of a diazonium salt, such as benzene-diazonium chloride, it is usual to dissolve the amine in a slight excess (about 2 2 molecular equivalents) of dilute hydrochloric acid (or alternatively to dissolve the crystalline amine hydrochloride in i 2 equivalents of the acid) and then add an aqueous solution of a metallic nitrite. Nitrous acid is thus generated in situ, and reacts with the amine salt to give the diazonium compound. For a successful preparation of an aqueous solution of the diazonium salt, however, two conditions must always be observed ... 

Note. Useful information can often be obtained by adding (i) dilute H,SO or (ii) dilute NaOH solution to an aqueous solution of the substance under investigation. A precipitate with (i) usually indicates an aromatic carboxylic acid from a metallic or from an ammonium salt. A precipitate or oil with (ii) usually indicates an aromatic amine from an amine salt. 

AH corrosion inhibitors in use as of this writing are oil-soluble surfactants (qv) which consist of a hydrophobic hydrocarbon backbone and a hydrophilic functional group. Oil-soluble surfactant-type additives were first used in 1946 by the Sinclair Oil Co. (38). Most corrosion inhibitors are carboxyhc acids (qv), amines, or amine salts (39), depending on the types of water bottoms encountered in the whole distribution system. The wrong choice of inhibitors can lead to unwanted reactions. Eor instance, use of an acidic corrosion inhibitor when the water bottoms are caustic can result in the formation of insoluble salts that can plug filters in the distribution system or in customers vehicles. Because these additives form a strongly adsorbed impervious film at the metal Hquid interface, low Hquid concentrations are usually adequate. Concentrations typically range up to 5 ppm. In many situations, pipeline companies add their own corrosion inhibitors on top of that added by refiners. 

Fast Color Salts. In order to simplify the work of the dyer, diazonium salts, in the form of stable dry powders, were introduced under the name of fast color salts. When dissolved in water they react like ordinary diazo compounds. These diazonium salts, derived from amines, free from solubilizing groups, are prepared by the usual method and are salted out from the solutions as the sulfates, the metallic double salts, or the aromatic sulfonates. The isolated diazonium salt is sold in admixture with anhydrous salts such as sodium sulfate or magnesium sulfate. 

Salt Formation. Citric acid forms mono-, di-, and tribasic salts with many cations such as alkahes, ammonia, and amines. Salts may be prepared by direct neutralization of a solution of citric acid in water using the appropriate base, or by double decomposition using a citrate salt and a soluble metal salt. 

When a carbonyl group is bonded to a substituent group that can potentially depart as a Lewis base, addition of a nucleophile to the carbonyl carbon leads to elimination and the regeneration of a carbon-oxygen double bond. Esters undergo hydrolysis with alkali hydroxides to form alkali metal salts of carboxylic acids and alcohols. Amides undergo hydrolysis with mineral acids to form carboxylic acids and amine salts. Carbamates undergo alkaline hydrolysis to form amines, carbon dioxide, and alcohols. 

The applications of hydrophobic amine salts (see Table 5) as anion exchange extractants to recover a diverse range of metals in the form of anionic, usually chloro, complexes was reviewed4 in CCC (1987). The order of preference shown by this class of extractants for simple inorganic anions... 

Reactions of Metal Compounds with Amine Salts... 

From the anionic surfactants (Table 1.1) the most relevant is LAS with an annual global production volume of more than 3 X 1061 in 2001. LAS has a wide application because of its excellent detersive properties and cost-performance ratio. Commercial LAS is applied mainly in the formulation of powder and liquid laundry detergents. The calcium salts are used as an emulsifier in pesticide formulations their amine salts are used in dry cleaning and as degreasing agents in the metal industry [14]. 

The distribution of M depends on both the free amine salt in the organic phase and the concentration of free 17 in the aqueous phase until all metal in the aqueous phase is bound in the ML7 complex. At constant amine concentration, Eq. (4.64) indicates that a plot of Du vs. [L ] would have a linear slope p if the denominator of Eq. (4.64) is 1 i.e., the metal species in the aqueous phase are dominated by the uncomplexed metal ion At higher [L ] concentrations, where the ML7 complex begins to dominate in the aqneons phase, the >m valne becomes equal to [RNHL]. Equations (4.64) and (4.4) show that 5-shaped curves result for metals with large values. In a plot of Dm vs. [RNHL] ,j a straight line of slope p is obtained only at constant [L ]. From such measurements both p, and Pp can be evalnated. The following example illustrates this. 

The object of equilibration is to provide a solvent that will effectively extract the required species, either because of the form of the active constituent of the solvent or by maintaining the necessary extraction pH. As an example of the former condition, consider the extraction of uranium using a tertiary aliphatic amine as extractant. Extraction of metal species by such amines is considered to occur by liquid ion exchange (see Chapters 3 and 4). For a tertiary amine to act in this manner, it must be first converted to an amine salt ... 

The reaction to form the palladium complex is similar to that reported for amine salts, although here, because a bidentate chelating ligand is used, no chlorine atoms are retained in the complex, and the system is easy to strip. Also, as both reactions involve initial ion pair extraction, fast kinetics are observed with 3-5 min contact time to reach equilibrium at ambient temperature. The extraction conditions can be easily adjusted in terms of acidity to suit any relative metal concentrations and, because the reagent is used in the protonated form, good selectivity over base metals, such as iron and copper,... 

Another variation of the synthesis of biguanides utilising the condensation of cyano-compoimds and amines is the reaction of dicyanimide and two moles of amine (457, 465, 581, 582). In practice (457) a dicyanimide metal salt is fused, or heated in water or in an organic solvent with an amine salt, preferably between 90 and 130°. Condensation may also be effected using free dicyanimide in aqueous acid media (581). 

Types of catalysts used include mineral or oiganic acids and latent acids such as ammonurea salts, amine salts, and metal salts (49). One type of catalyst used in early commercial processing was amine hydrochloride. However, the fishy odor evolving from this material has caused this type of catalyst to be discarded. Metal salt catalysts such as magnesium chloride or zinc nitrate have been widely used over the years. However, because of effluent concerns, zinc salts have fallen into disuse. Magnesium nitrate has been suggested as an alternative catalyst (50). 

However, the production of the />-phenylenediamine [106-50-3] intermediate is more complex, because it involves the diazotization and coupling of aniline [65-53-3]. Aniline reacts with nitrogen oxides, produced via the oxidation of ammonia, to form 1,3-diphenyltriazene [136-35-6] in the process used by Du Pont (208,209) (see Amines, aromatic-aniline and its derivatives). In the Akzo process a metal nitrite salt and acid in water is used (210). The triazene rearranges in the presence of acid and an excess of aniline to form predominately the p-aminoazobenzene [60-09-3] and a small amount of the ortho isomer, 0-aminoazobenzene [2835-58-7]. The mixture of isomers is catalytically reduced to the respective diamines, and they are then separated from the aniline, which is recycled (208,209). The 0-phenylenedi amine [95-54-5] is used in the manufacture of herbicides (see Amines, aromatic-phenylenediamines). 

Solvent extraction of base metals by amine salts 802... 

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