Heavy metal reducing agents

Reference to the stability of allyloxycarbonyl groups towards various heavy-metal reducing agents is made in Chapter 5i and to glycosylation via borate esters in Chapter 17. 

Both the acid and its salts are powerful reducing agents. They reduce, for example, halogens to halides, and heavy metal cations to the metal. Copper(H) ion is reduced further to give copper(I) hydride, a red-brown precipitate ... 

Phosphonic acid and hydrogen phosphonates are used as strong but slow-acting reducing agents. They cause precipitation of heavy metals from solutions of their salts and reduce sulfur dioxide to sulfur, and iodine to iodide in neutral or alkaline solution. 

Another approach used to reduce the harmful effects of heavy metals in petroleum residues is metal passivation. In this process an oil-soluble treating agent containing antimony is used that deposits on the catalyst surface in competition with contaminant metals, thus reducing the catalytic activity of these metals in promoting coke and gas formation. Metal passivation is especially important in fluid catalytic cracking (FCC) processes. Additives that improve FCC processes were found to increase catalyst life and improve the yield and quality of products. ... 

Ferrous sulfide acts as a reducing agent at pH 8 to 9 for reduction of hexavalent chromium and then precipitates the trivalent chromium as a hydroxide in one step without pH adjustment.5162 So, the hexavalent chromium in the nickel-chromium plating wastewater does not have to be isolated and pretreated by reduction to the trivalent form. The new process is applicable for removal of all heavy metals. All heavy metals other than chromium are removed as insoluble metal sulfides, M(II)S. 

As an example, when automotive catalytic mufflers and converters were introduced many years ago, the automobile industry required the petrochemical industry to eliminate lead from gasoline since lead degraded and reduced the effectiveness of the catalyst and caused the destruction of the gasoline. One set of industrial compounds that can harm catalysts are halogens, a family of compounds that include chlorine, bromine, iodine, and fluorine. Bromine, while not prevalent in industry, is present in chemical plants. Freons are fluorine compounds. Silicone is another compound that is deleterious to catalysts. It is used as a slip agent, or a lubricant, in many industrial processes. Phosphorous, heavy metals (zinc, lead), sulfur compounds, and any particulate can result in shortening the life of the catalyst. It is necessary to estimate the volume or the amount of each of those contaminants, to assess the viability of catalytic technologies for the application. 

Dexrazoxane (Zinecard) [Chelating Agent] Uses Prevent anthracycline-induced (eg, doxorubicin) cardiomyopathy Action Chelates heavy metals binds intracellular iron prevents anthracycline-induced free radicals Dose 10 1 ratio dexrazoxane doxorubicin 30 min prior to each dose, 5 1 ratio w/ CrCl <40 mL/min Caution [C, ] Contra Component sensitivity Disp Inj SE -1-BM (esp leukopenia), fever, Infxn, stomatitis, alopecia, NA /D Interactions t Length of muscle relaxation Wf succinylcholine EMS Given concurrent w/a chemo agent for treating CA to prevent cardiotox monitor for Infxn and reduced cardiac Fxn use caution w/ succinylcholine, reduced doses may be needed OD May cause extreme BM suppression symptomatic and supportive... 

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