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Through a variety of mechanisms, the removal of a hydride equivalent converts a primary or secondary alcohol to an aldehyde or ketone, respectively. The oxidation of primary alcohols to carboxylic acids normally proceeds via the corresponding aldehyde, which is transformed via an aldehyde hydrate (gem-diol, R-CH(OH) 2) by reaction with water ...
In the above equation, T F is the normal freezing point of the pure solvent (273 K for water, for example); a liq is the activity of the solvent in the solution (water activity for aqueous solution); ΔH fus T F is the enthalpy change of fusion of the pure solvent at T F, which is 333.6 J/g for water at 273 K; ΔC fus p is the difference ...
At an atomic level, the reduction in the force acting on a charge results from water molecules forming a hydration shell around it. This fact makes water a very good solvent for charged compounds like salts. Ethanol is much less polar than water, with a dielectric constant of 24.3 (at 25 °C). This means that adding ethanol to a solution ...
Phosphomolybdic acid is the heteropolymetalate with the formula H 3 [Mo 12 PO 40]·12H 2 O. It is a yellow solid, although even slightly impure samples have a greenish coloration. It is also known as dodeca molybdophosphoric acid or PMA, is a yellow-green chemical compound that is freely soluble in water and polar organic solvents such as ethanol.
DIBAL-H can selectively reduce acid chlorides to the aldehyde level if only one equivalent is used at low temperatures. [12] LiAlH(OtBu) 3 (formed from LiAlH 4 and tBuOH in situ) behaves similarly. [13] The idealized equation for the reduction of an acid chloride to an aldehyde by lithium aluminium hydride is:
The classic example of a dehydration reaction is the Fischer esterification, which involves treating a carboxylic acid with an alcohol to give an ester RCO 2 H + R′OH ⇌ RCO 2 R′ + H 2 O. Often such reactions require the presence of a dehydrating agent, i.e. a substance that reacts with water.
Chemical drawing of the mechanism of the Dess–Martin oxidation. The reaction produces two equivalents of acetic acid. It can be buffered with pyridine or sodium bicarbonate in order to protect acid-labile compounds. The rate of oxidation can be increased by the addition of water to the reaction mixture. [3]
Under ideal conditions the reaction produces 50% of both the alcohol and the carboxylic acid (it takes two aldehydes to produce one acid and one alcohol). [5] This can be economically viable if the products can be separated and both have a value; the commercial conversion of furfural into furfuryl alcohol and 2-furoic acid is an example of this ...