Metallic salts, reactions

Schweikhardt, R.D. "Metal-Salt Reactions in Molten Systems of Plutonium Metal and NaCl, NaCl-KCl, and NaCl-KCl-MgCl2" thesis, Univ. of Denver, August 1966. 

Table 4.1. Standard Reduction Potentials for Metals and Metal Salts Reaction...

The production of nanoparticles was done by mixing of salt and various plant sources of extracts to maintain the exact size, shape, and morphological features by varying several conditions like pH, temperature, concentration of metal salt, reaction time, reaction medium, etc. by maintaining these parameters one can synthesize metal nanoparticles in a required morphological formation (Madhumitha and Roopan, 2013). 

These addition reactions of unsaturated polymers, like liquid polybutadiene, developed into preparations of useful commercial materials. The patent literature describes procedures that use hydrogen peroxide in the presence of organic acids or their heavy metal salts. Reaction conditions place a limitation on the molecular weights of the polymers, because it is easier to handle lower-viscosity solutions. A modification of the procedures is to use peracetic acid in place of hydrogen peroxide. The most efficient methods rely upon formations of organic peracids in situ with cationic exchange resins acting as catalysts. This can be illustrated as follows ... 

A study of the interaction of hafiiium with the NaCl-KCl-K2HfF6 melt indicates the absence of metal -salt reaction with the formation of lower oxidation states [7]. It has been shown [8] that at low anodic current densities (up to about 0.02 A/cm ) the mean valence of hafiiium is close to four in the melt NaCl-KCl-K2HfF6 (10 w/o). This is due to the fact that this current density is not above the limiting diffusion current density for hafiiium dissolution according to reaction ... 

Study of metal-salt reactions in molten salts is of great practical and scientific value in the electrolysis of refi-actory metals and in the study of the electrochemical properties of compounds of low oxidation states which are formed in contact with metal. Metal-salt reaction has a great influence on current efficiency and the granulometric composition of niobium powders during electrolysis of the KCl-KF- K2NbF7 melt with... 

An equimolar mixture of sodium and potassium chloride containing 10-30 w/o potassium heptafluoroniobate (K2Nbp7) was used as the melt. When the metal is immersed in the NaCl-KCl-K2Nbp7 melt, the metal-salt reaction spontaneously takes place with formation of the reduced form of niobium ... 

The metal-salt reaction takes place against the background of the NaCl-KCl melt, and for this reason formation of NbPsCl complexes is favoured. The formation of Nbp6 and Nbp6Cl complexes is also possible. Nb(IV) complexes diffuse to the steel substrate and then disproportionate on its surface with the formation of niobium carbide ... 

We have shown earlier that it is possible to calculate the equilibrium constant of a metal-salt reaction from linear sweep voltammetry data [1]. The results of [1] also enable us to determine the thermodynamic properties of compounds during their formation from elements. 

Since AG = -2,303RT logK for the metal-salt reaction we got in the melt NaCl-KCl ... 

It is a dibasic acid, and forms stable metallic salts. Distillation with soda lime gives benzene. Readily dehydrated to phthalic anhydride. Its reactions are similar to phthalic anhydride in which form it is almost invariably used. 

Consequently they cannot be prepared by the addition of sulphide ions to a solution of the metal salt, the hydrated metal ions being so strongly acidic that the following reaction occurs, for example... 

Of course, these schemes indicate only that the overall reactions may be classified as nucleophilic 1,3-substitutions and, in the last case, as electrophilic 1,3-substitut ions. The reactions often proceed only in the presence of catalytic or stoichiometric amounts of transition metal salts, while in their absence 1,1--substitutions or other processes are observed. The 1,1-substitutions are also catalyzed by salts of transition metals, and it is not yet well understood, which factors influence the 1,1 to 1,3-ratio. In a number of 1,3-Substitutions there is... 

The alka-l,2,4-trienes (ailenylaikenes) 12 are prepared by the reaction of methyl propargyl carbonates with alkenes. Alkene insertion takes place into the Pd—C bond of the ailenyipailadium methoxide 4 as an intermediate and subsequent elimination of/3-hydrogen affords the 1,2,4-triene 12. The reaction proceeds rapidly under mild conditions in the presence of KBr. No reaction takes place in the absence of an alkali metal salt[4j. 

In 1875, Mulder (43) extended the synthesis reaction of thiohydantoine to the ethyl ester and amide of chloroacetic acid. Claus (44) demonstrated the acidic properties of thiohydantoin and its ability to form metallic salts. 

BackTitrations. In the performance of aback titration, a known, but excess quantity of EDTA or other chelon is added, the pH is now properly adjusted, and the excess of the chelon is titrated with a suitable standard metal salt solution. Back titration procedures are especially useful when the metal ion to be determined cannot be kept in solution under the titration conditions or where the reaction of the metal ion with the chelon occurs too slowly to permit a direct titration, as in the titration of chromium(III) with EDTA. Back titration procedures sometimes permit a metal ion to be determined by the use of a metal indicator that is blocked by that ion in a direct titration. Eor example, nickel, cobalt, or aluminum form such stable complexes with Eriochrome Black T that the direct titration would fail. However, if an excess of EDTA is added before the indicator, no blocking occurs in the back titration with a magnesium or zinc salt solution. These metal ion titrants are chosen because they form EDTA complexes of relatively low stability, thereby avoiding the possible titration of EDTA bound by the sample metal ion. 

Oxidation. Acetaldehyde is readily oxidised with oxygen or air to acetic acid, acetic anhydride, and peracetic acid (see Acetic acid and derivatives). The principal product depends on the reaction conditions. Acetic acid [64-19-7] may be produced commercially by the Hquid-phase oxidation of acetaldehyde at 65°C using cobalt or manganese acetate dissolved in acetic acid as a catalyst (34). Liquid-phase oxidation in the presence of mixed acetates of copper and cobalt yields acetic anhydride [108-24-7] (35). Peroxyacetic acid or a perester is beheved to be the precursor in both syntheses. There are two commercial processes for the production of peracetic acid [79-21 -0]. Low temperature oxidation of acetaldehyde in the presence of metal salts, ultraviolet irradiation, or osone yields acetaldehyde monoperacetate, which can be decomposed to peracetic acid and acetaldehyde (36). Peracetic acid can also be formed directiy by Hquid-phase oxidation at 5—50°C with a cobalt salt catalyst (37) (see Peroxides and peroxy compounds). Nitric acid oxidation of acetaldehyde yields glyoxal [107-22-2] (38,39). Oxidations of /)-xylene to terephthaHc acid [100-21-0] and of ethanol to acetic acid are activated by acetaldehyde (40,41). 

The Acetaldehyde Oxidation Process. Liquid-phase catalytic oxidation of acetaldehyde (qv) can be directed by appropriate catalysts, such as transition metal salts of cobalt or manganese, to produce anhydride (26). Either ethyl acetate or acetic acid may be used as reaction solvent. The reaction proceeds according to the sequence... 

Complexes of DMAC and many inorganic haHdes have been reported (20). These complexes are of iaterest because they catalyze a number of organic reactions. Complexes of DMAC and such heavy metal salts as NiBr2 exert a greater catalytic activity than the simple salts (21). The crystalline complex of SO and dimethylacetamide has been suggested for moderating the reaction conditions ia sulfation of leuco vat dyestuffs (22). 

Health and Safety Factors. Although butynediol is stable, violent reactions can take place in the presence of certain contaminants, particularly at elevated temperatures. In the presence of certain heavy metal salts, such as mercuric chloride, dry butynediol can decompose violently. Heating with strongly alkaline materials should be avoided. 

The reaction is generally carried out at atmospheric pressure and at 350—400°C. A variety of catalysts, eg, bases and metal salts and oxides on siUca or alumina—sihcates, have been patented (86—91). Conversions are in the 30—70% range and selectivities in the 60—90% range, depending on the catalyst and the ratio of formaldehyde to acetate. 

The reactions are catalyzed by tertiary amines, quaternary ammonium salts, metal salts, and basic ion-exchange resins. The products are difficult to purify and generally contain low concentrations of acryhc acid and some diester which should be kept to a minimum since its presence leads to product instabihty and to polymer cross-linking. 

Salt Formation. Salt-forming reactions of adipic acid are those typical of carboxylic acids. Alkali metal salts and ammonium salts are water soluble alkaline earth metal salts have limited solubiUty (see Table 5). Salt formation with amines and diamines is discussed in the next section. 

In general, the reactions of the perfluoro acids are similar to those of the hydrocarbon acids. Salts are formed with the ease expected of strong acids. The metal salts are all water soluble and much more soluble in organic solvents than the salts of the corresponding hydrocarbon acids. Esterification takes place readily with primary and secondary alcohols. Acid anhydrides can be prepared by distillation of the acids from phosphoms pentoxide. The amides are readily prepared by the ammonolysis of the acid haUdes, anhydrides, or esters and can be dehydrated to the corresponding nitriles (31). 

The metallic salts of trifluoromethanesulfonic acid can be prepared by reaction of the acid with the corresponding hydroxide or carbonate or by reaction of sulfonyl fluoride with the corresponding hydroxide. The salts are hydroscopic but can be dehydrated at 100°C under vacuum. The sodium salt has a melting point of 248°C and decomposes at 425°C. The lithium salt of trifluoromethanesulfonic acid [33454-82-9] CF SO Li, commonly called lithium triflate, is used as a battery electrolyte in primary lithium batteries because solutions of it exhibit high electrical conductivity, and because of the compound s low toxicity and excellent chemical stabiUty. It melts at 423°C and decomposes at 430°C. It is quite soluble in polar organic solvents and water. Table 2 shows the electrical conductivities of lithium triflate in comparison with other lithium electrolytes which are much more toxic (24). 

The primary and secondary alcohol functionahties have different reactivities, as exemplified by the slower reaction rate for secondary hydroxyls in the formation of esters from acids and alcohols (8). 1,2-Propylene glycol undergoes most of the typical alcohol reactions, such as reaction with a free acid, acyl hahde, or acid anhydride to form an ester reaction with alkaU metal hydroxide to form metal salts and reaction with aldehydes or ketones to form acetals and ketals (9,10). The most important commercial appHcation of propylene glycol is in the manufacture of polyesters by reaction with a dibasic or polybasic acid. 

---