Reduction review

Clemmensen Reduction (Review) The Clemmensen reduction commonly converts acylbenzenes (from Friedel-Crafts acylation, Section 17-1 IB) to alkylbenzenes, but it also works with other ketones and aldehydes that are not sensitive to acid. The carbonyl compound is heated with an excess of amalgamated zinc (zinc treated with mercury) and hydrochloric acid. The actual reduction occurs by a complex mechanism on the surface of the zinc. 

Several studies have shown that the more crystalline the Fe(III) and Mn(IV) oxides, the slower the rate of their reduction (reviewed by Lovley, 1991, 2004). In laboratory experiments, Ottow and Klopotek (1969, cited by Lovley, 1987) reported that the reduction capacity of select iron minerals was found to be in the order of FeP04 > Fe(OH)j > FeOOH > Fe203. Amorphous and poorly crystalline forms of Fe(III) and Mn(IV) oxides dominate wetlands that undergo frequent wet and dry cycles. These systems are dynamic, and repeated oxidation-reduction reactions involving iron and manganese will not allow time for stable crystalline forms of Fe(III) and Mn(IV) oxides to form in these systems. Strong relationships are observed between Fe(III) reduction rates and poorly crystallined forms of Fe(III) oxides (as determined by hydroxylamine extraction) in fresh and brackish water sediments (Lovley and Philips, 1987). 

The Agency had three requirements for setting up a source reduction review sufficient information for the review, a workable assessment methodology and the ability to propose practical solutions to waste problems. 

Other Requirements. Success of source reduction reviews depended upon a reasonable assessment methodology that would identify the most wasteful processes and develop suggestions to improve them without requiring large resource expenditures on the Agency s part. A basic premise was that chemists could identify quickly those PMN cases with the greatest waste so that intensive review and development of options for reducing the wastes would only be done on the most appropriate cases. 

In February 1991, EPA chemists initiated a pilot study to test the assessment process and to determine whether source reduction reviews were feasible. EPA chemists designed a process to concentrate resources on those cases most likely to yield significant source reduction opportunities. The process began with a quick sort to determine which PMN cases had sufficient potential for further study. This was followed by a preliminary assessment to identify those cases with the highest pollution prevention potential and then a detailed assessment during which pollution prevention options were developed and analyzed. Finally, the Agency determined whether there were source reduction suggestions of sufficient merit to justify a letter to the PMN submitter. 

U.S. Environmental Protection Agency, Source Reduction Review Project, EPA-lOO/R-92/002, Office of Pollution Prevention and Toxics, Washington, DC, August 1992. 

The standard has both general and detailed requirements. General requirements include documentation of the system safety approach, identification of hazards, risk assessment, identification of risk mitigation measures, reduction of risk to an acceptable level, verification of risk reduction, review of hazards and acceptance of residual risk, and tracking of hazards and residual risk. When a government contract specifies MIL-STD-882D and no other requirement, only the general requirements apply. 

Etbyleneketones, polycyclic metal-ammonia reduction (review) 14,88s43... 

Hepten-2-one electrolyzed at a cathode potential of - 2.7 v. in dioxane-methanol containing tetraethylammonium tosylate as supporting electrolyte with carbon rod electrodes and ceramic cylinder as cathode-anode diamber divider 1,2-di-methylcyclopentanol. Y 66%. F. e. s. T. Shono and M. Mitani, Am. Soc. 93, 5284 (1971) stereochemistry of electrochemical reductions, review, cf. A. J. Fry, Topics Curr. Chem. 34, 1 (1972). 

Rosenson RS, Tagney CC. Antithrombotic properties of statins implications for cardiovascular event reduction Review. JAMA 1998 279 1643-1650. 

Benkeser reduction -, comparison with Birch reduction, review... 

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