Alcohols: Identification, Production, and Reactions

Practice flashcards covering the nomenclature, classification, properties, industrial production, and chemical reactions of alcohols based on the provided lecture notes.

Alcohol (General Formula)

Alcohols have the functional group $-OH$ attached to a hydrocarbon chain, with the general formula $CH_{2}OH$ (note: commonly $C_{n}H_{2n+1}OH$) or shortened to $ROH$.

Primary ($1^{\circ}$) Alcohols

Alcohols where the carbon with the $-OH$ group is attached to one $R$ group (two hydrogen atoms), or in the case of methanol, no $R$ groups.

Secondary ($2^{\circ}$) Alcohols

Alcohols where the $-OH$ group is attached to a carbon with two $R$ groups and one hydrogen atom.

Tertiary ($3^{\circ}$) Alcohols

Alcohols where the carbon bonded to the $-OH$ group is attached to three $R$ groups and has no hydrogen atoms.

Glycerol

The common name for propane-1,2,3-triol, which can be obtained from fats and oils in living organisms.

Antifreeze

A substance containing ethane-1,2-diol added to vehicle cooling systems to prevent the coolant from freezing at winter temperatures.

$C-O-H$ bond angle

An angle of approximately $105^{\circ}$ (or $104.5^{\circ}$) in alcohols, narrowed from the tetrahedral $109.5^{\circ}$ due to repulsion between two lone pairs on the oxygen atom.

Hydration of Ethene

An industrial method for producing ethanol by reacting ethene with steam using a phosphoric acid catalyst.

Fermentation

The process of converting carbohydrates from plants into ethanol and carbon dioxide using enzymes from yeast at a temperature of about $35\,^{\circ}C$ in anaerobic conditions.

Biofuel

A fuel derived or produced from renewable biological sources.

Carbon-neutral fuel

A fuel where the carbon dioxide released during combustion is balanced by the carbon dioxide absorbed by the plant during photosynthesis, such as ethanol made by fermentation.

Elimination reaction

A reaction where a small molecule, such as water, leaves the parent molecule; in alcohols, these are always dehydrations.

Dehydration

A process where alcohols are heated with excess hot concentrated sulfuric acid or passed over heated aluminium oxide ($Al_{2}O_{3}$) at $600\,K$ to form an alkene and water.

Potassium Dichromate ($VI$)

An oxidising agent acidified with dilute sulfuric acid that changes from orange ($Cr(VI)$) to green ($Cr(III)$) when reacting with primary or secondary alcohols.

Aldehydes

The first oxidation product of primary alcohols, characterized by the functional group $RCHO$; they are named using the suffix -al.

Ketones

The oxidation product of secondary alcohols, characterized by the carbonyl group $C=O$ within the body of the hydrocarbon chain ($RCOR^{\prime}$); they are named using the suffix -one.

Carboxylic Acids

The product of the complete oxidation of primary alcohols, characterized by the functional group $RCOOH$.

Reflux

A laboratory technique where vapour condenses and drips back into the reaction flask to allow prolonged heating without loss of volatile reactants or products.

Distillation

A process used to separate substances based on different boiling points; for example, separating ethanal ($294\,K$) from an oxidation mixture before it turns into ethanoic acid.

Tollens' reagent

A solution of silver nitrate in aqueous ammonia used to test for aldehydes; a positive result forms a silver mirror as $Ag^{+}$ ions are reduced to metallic $Ag$.

Fehling's solution

A blue solution containing copper($II$) complex ions that forms a brick-red precipitate of copper($I$) oxide when warmed with an aldehyde.

Carbonyl group

The $C=O$ group found in both aldehydes and ketones.