oxidizing agent

Examples of oxidizing agent in the following topics:

• Manganese

  • The most common oxidation states of the metal manganese are +2, +3, +4, +6, and +7; the +2 oxidation state is the most stable.
  • Manganese compounds where manganese is in oxidation state of 7+ are powerful oxidizing agents.
  • Compounds with oxidation states 5+ (blue) and 6+ (green) are strong oxidizing agents.
  • The 3+ oxidation state is seen in compounds like manganese(III) acetate; these are very powerful oxidizing agents.
  • Predict the oxidation or reduction propensity of a manganese species given its formula or oxidation state.

• Oxidation

  • The carbon atom of a carbonyl group has a relatively high oxidation state.
  • Useful tests for aldehydes, Tollens' test, Benedict's test & Fehling's test, take advantage of this ease of oxidation by using Ag(+) and Cu(2+) as oxidizing agents (oxidants).
  • The Fehling and Benedict tests use cupric cation as the oxidant.
  • This deep blue reagent is reduced to cuprous oxide, which precipitates as a red to yellow solid.
  • All these cation oxidations must be conducted under alkaline conditions.

• Free Energy and Cell Potential

  • This is related to how easily the oxidized species gives up electrons and how badly the reduced species wants to gain them.
  • Since the standard electrode potentials are given in their ability to be reduced, the bigger the standard reduction potentials, the easier they are to be reduced; in other words, they are simply better oxidizing agents.
  • F2 reduces easily and is therefore a good oxidizing agent.
  • In contrast, Li(s) would rather undergo oxidation, so it is a good reducing agent.
  • In the example of Zn2+, whose standard reduction potential is -0.76 V, it can be oxidized by any other electrode whose standard reduction potential is greater than -0.76 V and can be reduced by any electrode with standard reduction potential less than -0.76 V.

• Electrons and Energy

  • The removal of an electron from a molecule via a process called oxidation results in a decrease in the potential energy stored in the oxidized compound.
  • RH (Reducing agent) + NAD+ (Oxidizing agent) → NADH (Reduced) + R (Oxidized)
  • A compound that reduces another is called a reducing agent.
  • In the above equation, RH is a reducing agent and NAD+ is reduced to NADH.
  • In the above equation, NAD+ is an oxidizing agent and RH is oxidized to R.

• Phosphorus Compounds as Reducing Agents

  • Trivalent phosphorus is easily oxidized.
  • The triphenylphosphine oxide produced in reactions 1 & 3 is a very stable polar compound, and in most cases it is easily removed from the other products.
  • Triphenylphosphine is also oxidized by halogens, and with bromine yields dibromotriphenylphosphorane, a crystalline salt-like compound, useful for converting alcohols to alkyl bromides.
  • As in a number of earlier examples, the formation of triphenylphosphine oxide in the irreversible SN2 step provides a thermodynamic driving force for the reaction.

• Oxidation of Phenols

  • Phenols are rather easily oxidized despite the absence of a hydrogen atom on the hydroxyl bearing carbon.
  • The redox equilibria between the dihydroxybenzenes hydroquinone and catechol and their quinone oxidation states are so facile that milder oxidants than chromate (Jones reagent) are generally preferred.
  • One such oxidant is Fremy's salt, shown below.
  • Reducing agents other than stannous chloride (e.g.
  • The solvent of choice for these oxidations is usually methanol or dimethylformamide (DMF).

• Oxides

  • Metal oxides typically contain an anion of oxygen in the oxidation state of −2.
  • Most of the Earth's crust consists of solid oxides, the result of elements being oxidized by the oxygen in air or water.
  • Although most metal oxides are polymeric, some oxides are monomeric molecules.
  • Those attacked only by acids are basic oxides; those attacked only by bases are acidic oxides.
  • A common and cheap reducing agent is carbon in the form of coke.

• Oxidation States of Nitrogen

  • In comparing the chemistry of the amines with alcohols and ethers, we discover many classes of related compounds in which nitrogen assumes higher oxidation states, in contrast to limited oxidation states of oxygen.
  • Amine oxides are prepared by oxidizing 3º-amines or pyridines with hydrogen peroxide or peracids (e.g.
  • If one of the alkyl substituents consists of a long chain, such as C12H25, the resulting amine oxide is an amphoteric surfactant and finds use in shampoos and other mild cleaning agents.
  • Cope elimination of diastereomeric amine oxides, such as those shown in examples #2 & 3 above, provide proof of the syn-relationship of the beta-hydrogen and amine oxide groups.
  • Nitroxides are oxidized to unstable oxammonium cations by halogens.

• Iron Oxidation

  • G. metallireducens) can use toxic hydrocarbons such as toluene as a carbon source, there is significant interest in using these organisms as bioremediation agents in ferric iron-rich contaminated aquifers .
  • There are three distinct types of ferrous iron-oxidizing microbes.
  • The second type of microbes oxidizes ferrous iron at cirum-neutral pH.
  • Biochemically, aerobic iron oxidation is a very energetically poor process which therefore requires large amounts of iron to be oxidized by the enzyme rusticyanin to facilitate the formation of proton motive force.
  • Outline the purpose of iron oxidation and the three types of ferrous iron-oxidizing microbes (acidophiles, microaerophiles and anaerobic photosynthetic bacteria)

• Iron, Cobalt, Copper, Nickel, and Zinc

  • Copper oxidizes—with some difficulty—to the +1 state in halides and an oxide, and to the +2 state in salts such as copper sulfate CuSO4.
  • Zinc and cadmium are soft metals that easily oxidize to the +2 oxidation state.
  • In galvanization, zinc coats iron by oxidizing to form a protective layer of zinc oxide (ZnO) that protects the iron from oxidation.
  • Zinc oxide is much safer than lead oxide, and it is often used in white paint.
  • Iron, cobalt, and nickel are fairly good reducing agents, so they rarely appear uncombined in nature.