Metal ions manganese

DIISOTHIOCYANATOTETRAPYRIDINE AND DIISOTHIOCYANATODIPYRIDINE COMPLEXES OF DIPOSITIVE FIRST-TRANSITION-METAL IONS (MANGANESE, IRON, COBALT,... 

Fig. 9. Sequential hydration energies in kj/mol of the singly charged alkali ions, lithium (open circles) and sodium (open diamonds), the alkaline earth, magnesium (open triangles), and two first row transition metal ions, manganese (solid triangles) and copper (closed circles). All data taken from Table 3...

In this chapter, the redox and hydrolytic processes that result in the formation of nano- and microparticles will be discussed in metal ions (manganese, iron, lead, zinc, and silver ions)/montmorillonite (bentonite) systems. In addition, the catalytic diacetylation reaction of aromatic aldehydes will be shown. 

The enzyme responsible for carbon dioxide fixation is called acetyl-CoA carboxylase and is dependent upon the presence of the metal ion manganese and also the vitamin biotin. In fact it is the biotin that first reacts with the C02 in an energy-requiring reaction that is driven by the simultaneous breakdown of ATP. The car-boxybiotin which is formed cab now be thought of as an activated carrier molecule, very similar to UDPG. It can easily transfer its C02 to acetyl CoA to give malony 1 CoA in the following reactions ... 

Butane-Naphtha Catalytic Liquid-Phase Oxidation. Direct Hquid-phase oxidation ofbutane and/or naphtha [8030-30-6] was once the most favored worldwide route to acetic acid because of the low cost of these hydrocarbons. Butane [106-97-8] in the presence of metallic ions, eg, cobalt, chromium, or manganese, undergoes simple air oxidation in acetic acid solvent (48). The peroxidic intermediates are decomposed by high temperature, by mechanical agitation, and by action of the metallic catalysts, to form acetic acid and a comparatively small suite of other compounds (49). Ethyl acetate and butanone are produced, and the process can be altered to provide larger quantities of these valuable materials. Ethanol is thought to be an important intermediate (50) acetone forms through a minor pathway from isobutane present in the hydrocarbon feed. Formic acid, propionic acid, and minor quantities of butyric acid are also formed. 

Diacyl peroxide decompositions also are cataly2ed by the metal ions of copper, iron, cobalt, and manganese ... 

Metals. Transition-metal ions, such as iron, copper, manganese, and cobalt, when present even in small amounts, cataly2e mbber oxidative reactions by affecting the breakdown of peroxides in such a way as to accelerate further attack by oxygen (36). Natural mbber vulcani2ates are especially affected. Therefore, these metals and their salts, such as oleates and stearates, soluble in mbber should be avoided. 

Metal-Catalyzed Oxidation. Trace quantities of transition metal ions catalyze the decomposition of hydroperoxides to radical species and greatiy accelerate the rate of oxidation. Most effective are those metal ions that undergo one-electron transfer reactions, eg, copper, iron, cobalt, and manganese ions (9). The metal catalyst is an active hydroperoxide decomposer in both its higher and its lower oxidation states. In the overall reaction, two molecules of hydroperoxide decompose to peroxy and alkoxy radicals (eq. 5). 

NE is unstable in light and air, especially at neutral and alkaline pH. Oxidation to noradrenochrome occurs in the presence of oxygen and such divalent metal ions as copper, manganese, and nickel. 

The oxidation of hydrocarbons, including hydrocarbon polymers, takes the form of a free-radical chain reaction. As a result of mechanical shearing, exposure of ultraviolet radiation, attack by metal ions such as those of copper and manganese as well as other possible mechanisms, a hydrocarbon molecule breaks down into two radicals... 

Manganese, copper, iron, cobalt and nickel ions can all initiate oxidation. Untinned copper wire can have a catastrophic effect on natural rubber compounds with which it comes into contact. Inert fillers for use in rubbers are usually tested for traces of such metal ions, particularly copper and manganese. The problem is perhaps less serious in saturated hydrocarbon polymers but still exists. 

Metal ions in their reduced state also undergo reactions with BrCl. Examples include iron and manganese. 

The sulfides are fewer and less familiar than the oxides but, as is to be expected, favour lower oxidation states of the metals. Thus manganese forms MnS2 which has the pyrite structure (p. 680) with discrete Mn and 82 ions and is converted on heating to MnS and... 

Some enzymes require metal ions - such as cobalt, manganese or zinc - for their activity if these are removed by the ionic liquid by complexation, enzyme inactivation may occur. 

Transition metal ions. Transition metal ions impart color to many of their compounds and solutions, (a) Bottom row (left to right) iron(lll) chloride. copper ll) sulfate, manganese(ll) chloride, cobalt(ll) chloride. Top row (left to right) chromium(lll) nitrate, iron(ll) sulfate, nickel(ll) sulfate, potassium dichromate, (b) Solutions of the compounds in (a) in the order listed above. 

One of the possible problems of using the complex mixtures is the presence of unwanted materials such as certain metal ions, particularly manganese and iron. In addition, inhibitory compounds such as acetic add may be present All need to be removed before fermentation can proceed. 

Figure 12. Schematic drawing of the theoretical positions of the foreign metal ions in (a) 7 A phyl-lomanganates and (b) 10 A phyllomanganates. The foreign ions can be located above a manganese vacancy (between the Mn - O layer and the sheet of water molecules) and within the layer, respectively (adapted from [47]).

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