Unit 7: Alcohols, Phenols and Ethers

Vocabulary flashcards covering the classification, nomenclature, preparation, physical properties, and chemical reactions of alcohols, phenols, and ethers from Unit 7.

Alcohols

Organic compounds formed when one or more hydrogen atoms of an aliphatic hydrocarbon are replaced by hydroxyl ($-OH$) groups, resulting in the general formula $R-OH$.

Phenols

Organic compounds containing one or more hydroxyl ($-OH$) groups directly attached to an $sp^2$ hybridised carbon atom of an aromatic ring system ($Ar-OH$).

Ethers

Organic compounds formed by substituting a hydrogen atom in a hydrocarbon by an alkoxy ($R-O-$) or aryloxy ($Ar-O-$) group, represented by the general formula $R-O-R'$ or $Ar-O-R$.

Monohydric, Dihydric, and Trihydric Alcohols

Classification of alcohols based on whether their molecules contain one, two, or three hydroxyl ($-OH$) groups, respectively.

Allylic Alcohols

Alcohols in which the $-OH$ group is attached to an $sp^3$ hybridised carbon atom adjacent to a carbon-carbon double bond (an allylic carbon).

Benzylic Alcohols

Alcohols in which the $-OH$ group is attached to an $sp^3$ hybridised carbon atom directly attached to an aromatic ring.

Vinylic Alcohols

Alcohols containing an $-OH$ group bonded directly to an $sp^2$ hybridised carbon atom of a carbon-carbon double bond, such as in $CH_2=CH-OH$.

Symmetrical Ethers (Simple Ethers)

Ethers in which the two alkyl or aryl groups attached to the oxygen atom are identical, such as diethyl ether ($C_2H_5OC_2H_5$).

Unsymmetrical Ethers (Mixed Ethers)

Ethers in which the two alkyl or aryl groups attached to the central oxygen atom are different, such as ethyl methyl ether ($C_2H_5OCH_3$).

Cresols

Monohydroxy methyl derivatives of benzene ($CH_3-C_6H_4-OH$), existing as ortho- ($2$-methylphenol), meta- ($3$-methylphenol), and para- ($4$-methylphenol) isomers.

Catechol

The common name for benzene-$1,2$-diol, a dihydric phenol containing two adjacent hydroxyl groups on a benzene ring.

Resorcinol

The common name for benzene-$1,3$-diol, a dihydric phenol containing two meta-positioned hydroxyl groups on a benzene ring.

Hydroquinone (Quinol)

The common name for benzene-$1,4$-diol, a dihydric phenol bearing two para-positioned hydroxyl groups on a benzene ring.

Anisole

The common and accepted IUPAC name for methyl phenyl ether ($C_6H_5OCH_3$, methoxybenzene).

Phenetole

The common name for ethyl phenyl ether ($C_6H_5OCH_2CH_3$, ethoxybenzene).

Acid-Catalysed Hydration of Alkenes

The electrophilic addition of water to alkenes in the presence of an acid catalyst to produce alcohols according to Markovnikov's rule.

Hydroboration–Oxidation

The addition of diborane ($(BH_3)_2$) to an alkene followed by oxidation with hydrogen peroxide in alkaline solution, yielding an alcohol equivalent to anti-Markovnikov hydration.

Grignard Synthesis of Alcohols

The nucleophilic addition of a Grignard reagent ($RMgX$) to a carbonyl group to form an adduct, which on hydrolysis yields a primary alcohol (from methanal), secondary alcohol (from other aldehydes), or tertiary alcohol (from ketones).

Cumene Process

The industrial synthesis of phenol by air oxidation of cumene (isopropylbenzene) to cumene hydroperoxide, followed by cleavage with dilute acid to yield phenol and acetone as a co-product.

Lucas Test

A test distinguishing primary, secondary, and tertiary alcohols using Lucas reagent ($\text{conc. } HCl$ and anhydrous $ZnCl_2$); tertiary alcohols produce immediate turbidity, secondary alcohols produce turbidity within 5 minutes, and primary alcohols show no turbidity at room temperature.

Esterification

The reaction of alcohols or phenols with carboxylic acids, acid anhydrides, or acid chlorides to form esters.

Acetylation

The chemical reaction introducing an acetyl group ($CH_3CO-$) into alcohols or phenols, such as the synthesis of aspirin from salicylic acid and acetic anhydride.

Pyridinium Chlorochromate (PCC)

A selective reagent prepared from chromium trioxide, pyridine, and $HCl$, used to oxidise primary alcohols to aldehydes without further oxidation to carboxylic acids.

Kolbe's Reaction

The electrophilic aromatic substitution of sodium phenoxide with carbon dioxide followed by acidification to produce ortho-hydroxybenzoic acid (salicylic acid) as the main product.

Reimer–Tiemann Reaction

The reaction of phenol with chloroform ($CHCl_3$) in the presence of sodium hydroxide to introduce an aldehyde ($-CHO$) group at the ortho position, forming salicylaldehyde.

Benzoquinone

A conjugated diketone obtained by the oxidation of phenol with chromic acid ($Na_2Cr_2O_7 / H_2SO_4$).

Picric Acid

The common name for $2,4,6$-trinitrophenol, a strongly acidic compound prepared by the nitration of phenol.

Denaturation of Alcohol

The process of making commercial ethanol unfit for drinking by adding copper sulphate (to impart colour) and pyridine (to impart a foul smell).

Williamson Ether Synthesis

A laboratory method for preparing symmetrical and unsymmetrical ethers via an $S_N2$ reaction between a primary alkyl halide and a sodium alkoxide or phenoxide.