Alcohols reaction with active metals

The acidity of alcohols is shown by their reaction with active metals to form hydrogen gas, and by their ability to displace the weakly acidic hydrocarbons from their salts (e.g., Grignard reagents) ... 

We have already seen how the acidity of alcohols resembles the acidity of water. Here two general approaches are presented for the removal of a proton from an alcohol to form an alkoxide ion reaction with strong bases (such as [(CH3)2CH]2N- or hydride) and reaction with active metals (especially alkali metals). Alkoxides are readily available species whose reactions will be explored at several places in this chapter. 

Reaction with Active Metals (Section 10.4) Alcohols react with Li, Na, K, and other active metals to form metal alkoxides, which are nearly the same or somewhat stronger bases than the alkali metal hydroxides such as NaOH and KOH. 

Reaction with Active Metals Alcohols react with active metals, such as sodium, much as water does. For example, methanol reacts with sodium to form sodium methoxide and hydrogen gas ... 

They are considerably acidic and react with active metals to liberate hydrogen gas. Thus, an alkoxide (RO ) can be prepared by the reaction of an alcohol with Na or K metal. 

Alcohols display the properties of weak acids. The reactions of alcohols with active metals (such as Na and K) are slower than the equivalent reactions with water. During these reactions, basic salts of the alkoxide ion (RO —) are produced. 

A number of useful reduction processes involve metals as the reducing agent. Scheme 4.3 lists some of the more important reactions that fall into this group. Before the advent of the metal hydrides, the reduction of ketones to alcohols with active metals, primarily sodium, using alcohols such as ethanol and propanol as solvent was an important synthetic process. This procedure, sometimes called the Bouvault-Blanc reduction, is seldom the method of choice nowadays. The mechanism involves electron transfer from the metal to the carbonyl in two separate stages. 

The various kinds of 2-ferrocene derivatives are synthesized by reaction with transition metal compounds in a manner similar to the orthometalation of phenyl compounds. The palladium compounds 7.54 of dimethylaminomethylferrocene react with carbon monoxide in methyl alcohol to give the 2-methoxycarbonyl compound 7.45, and subsequent treatment of the product with methyl iodide, sodium amalgam, and phosphoric acid gives l-methyl-2-carboxylic acid 7.55. Reduction of the 2-methoxycarbonyl compound 7.45, followed by treatment with NaOH, produces an alcohol 7.56, and oxidation of the compound 7.56 yields an aldehyde 7.57, as shown in Scheme 7.9. Since the starting material 7.54 is an optically active compound, as shown in Scheme 7.9, all of its derivatives are also optically active 1,2-ferrocene derivatives [68]. 

Reaction of Alcohols with Active Metals (Section 8.2C)... 

Willstatter expressed his mature conclusions at Cornell University in 1926, and in the same place on 29 April of that year, J. B. Sumner obtained from jack bean a new protein that crystallizes beautifully and whose solutions possess to an extraordinary degree the ability to decompose urea to ammonium carbonate. Sumner marshaled arguments that his octahedral crystals were practically uncontaminated with any other material. Solutions of the crystals exhibited greater urease activity per unit weight than any other preparation of the enzyme. Solvents that did not dissolve the crystals had little or no urease activity. The crystals were proteins by every test, and in solution urease activity behaved like a protein in its reactions with heavy metals, alkaloid reagents, alcohol, and acids. 

Considered initially as, in general, a simple extension of the direct reaction with alcohols for less active metals by application of an anodic potential, the anodic oxidation of metals turned to be a much more complicated process. At present, at least three different oxidation mechanisms have been proposed for different groups of metals ... 

Alcohols undergo a number of reactions including substitution, elimination (or dehydration), and oxidation. Alcohols also react with active metals to form strong bases. 

Phosphites. Tertiary phosphites are also commonly used and are particularly effective ia most mixed metal stabilizers at a use level of 0.25—1.0 phr. They can take part ia a number of different reactions duting PVC processing they can react with HCl, displace activated chlorine atoms on the polymer, provide antioxidant functionaHty, and coordinate with the metals to alter the Lewis acidity of the chloride salts. Typical examples of phosphites are triphenyl phosphite [101 -02-0], diphenyl decyl phosphite [3287-06-7], tridecyl phosphite [2929-86-4], and polyphosphites made by reaction of PCl with polyols and capping alcohols. The phosphites are often included in commercial stabilizer packages. 

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