Alcohols Phenols and Ethers Test - 11

Oxidation of alcohols to aldehydes is partial oxidation; aldehydes are further oxidized to carboxylic acids. Conditions required for making aldehydes are heat and distillation.

In aldehyde formation, the temperature of the reaction should be kept above the boiling point of the aldehyde and below the boiling point of the alcohol. Reagents useful for the transformation of primary alcohols to aldehydes are normally also suitable for the oxidation of secondary alcohols to ketones.

These include:

• Chromium-based reagents, such as Collins reagent (CrO₃·Py₂)
• PDC or PCC.
• Heat in the presence of Cu at 573K.

A chiral molecule is one that is not superimposable on its mirror image.
2-Butanol is a small molecule with a chirality center. It is the simplest alcohol containing an asymmetric carbon. For a better illustration, the four different substituents are shown in different colours.
Carbon atom C-2 of 2-butanol carries four different substituents H, CH₃, OH, and CH₂CH₃. Exchange of any two of these substituents would yield the opposite enantiomer. However, such an exchange does not occur spontaneously because it requires a bond breakage. Therefore, enantiomers are different, stable, coexisting compounds.

The formation of ethers by dehydration of the alcohol is a bimolecular reaction (S_N²) involving the attack of an alcohol molecule on a protonated alcohol molecule. In the method, the alkyl group should be unhindered. In case of secondary or tertiary alcohols, the alkyl group is hindered. As a result, elimination dominates substitution as 3° carbocation is more stable.

Hence, in place of ethers, alkenes are formed.

The Wurtz reaction, named after Charles-Adolphe Wurtz, is a coupling reaction in organic chemistry, organometallic chemistry and recently inorganic main group polymers, whereby two alkyl halides are reacted with sodium metal in dry ether solution to form a higher alkane: 2R–X + 2Na → R–R + 2NaX.

The most common cause of blindness from drinking is methanol. Methanol, otherwise known as methyl alcohol or wood alcohol, can damage the optic nerve and even kill you in high concentrations. During Prohibition, bootleggers were known to sell moonshine that contained methanol, and the practice continues abroad.

Lucas reagent is a solution of anhydrous zinc chloride (Lewis acid) in concentrated hydrochloric acid. It is used as a reagent to test alcohols and classify them in accordance to their reactivity. The reaction is a substitution reaction where the chloride of the zinc chloride gets replaced by the hydroxyl group of the alcohol.