Ethers Lecture Review

Comprehensive vocabulary flashcards covering the definition, nomenclature, properties, synthesis, and reactions of ethers based on lecture notes.

Ether

An organic compound in which two hydrocarbon groups are bonded to the same atom of oxygen, represented by the general formula $R-O-R^1$.

Symmetrical ethers

Ethers where two identical groups are attached to the oxygen atom, such as diethyl ether ($CH_3 - CH_2 - O - CH_2 - CH_3$).

Asymmetrical ethers

Also known as unsymmetrical ethers, these are ethers where two different groups are attached to the oxygen atom, such as ethyl methyl ether ($CH_3 - O - CH_2 - CH_3$).

IUPAC Rule for Ether Base Chain

Select the longest carbon chain as the base chain and give it the base name.

Alkoxy groupNaming

The hydrocarbon group that is not the base chain; its name is changed from ending in 'yl' to 'oxy' (e.g., methyl becomes methoxy).

Ether Dipole Moment

Ethers possess a small net dipole moment because the $C-O-C$ bond angle is not $180^{\circ}$ and the dipole moments of the two $C-O$ bonds do not cancel each other.

Boiling Point of Ethers

Boiling points are comparable to alkanes but very low compared to alcohols of comparable molecular mass due to the absence of hydrogen bonding in ethers.

Ether Solubility

Ethers are soluble in water because their oxygen atoms can form hydrogen bonds with water molecules, though solubility decreases as the number of carbon atoms increases.

Ether Hybridization

In ethers, the oxygen atom is $sp^3$ hybridized with a bond angle of $109.5^{\circ}$.

Dehydration of Alcohols (Ether Formation)

Alcohol undergoes dehydration in the presence of protic acids; for example, ethanol yields ethoxyethane in the presence of sulphuric acid at $413\,K$.

Williamson Synthesis

A laboratory method for preparing symmetrical and asymmetrical ethers involving an $SN2$ attack of an alkoxide ion on an alkyl halide.

Dry Silver Oxide Reaction

A method to produce ether by treating an alkyl halide with dry silver oxide: $2C_2H_5Br + Ag_2O \rightarrow C_2H_5 - O - C_2H_5 + 2AgBr$.Reference: 2C2H5Br + Ag2O → C2H5 – O – C2H5 + 2AgBr.

Cleavage of C-O Bonds

Ethers react with excess hydrogen halide (usually $HBr$ and $HI$) under concentrated conditions and high temperatures to produce alkyl halides and alcohol.

Reactivity of Hydrogen Halides with Ethers

The order of reactivity for the cleavage of $C-O$ bonds is $HI > HBr > HCl$.

Peroxide Formation

The process that occurs when ether is exposed to air in the presence of UV light or sunlight, forming a peroxide linkage.

Electrophilic Substitution in Aromatic Ethers

The alkoxy group ($-OR$) activates the aromatic ring and is ortho and para directing due to the lone pair of oxygen being involved in resonance.

Nitration of Anisole

An electrophilic substitution where anisole is treated with a mixture of concentrated $HNO_3$ and $H_2SO_4$ to yield ortho-Nitroanisole and para-Nitroanisole (major).

Friedel-Crafts Alkylation of Anisole

Involves the reaction of anisole with alkyl chloride using anhydrous aluminium chloride ($AlCl_3$) as a catalyst to introduce alkyl groups at ortho and para positions.

Friedel-Crafts Acylation of Anisole

The reaction of anisole with an acyl chloride in the presence of anhydrous aluminium chloride ($AlCl_3$) catalyst.

Dimethyl ether Use

Used as a refrigerant and as a solvent at low temperatures.

Diethyl ether Use

Used as a common ingredient in anesthesia for surgeries and as a solvent for oils, gums, and resins.

Phenyl ether Use

Utilized as a heat transfer medium because of its high boiling point.