Haloalkanes and Haloarenes Study Deck

Vocabulary-style flashcards covering the definitions, classifications, preparations, and reactions of haloalkanes and haloarenes as detailed in the provided transcript.

Haloalkane (Alkyl halide)

A compound formed by the replacement of hydrogen atom(s) in an aliphatic hydrocarbon by halogen atom(s), where the halogen is attached to an $sp^3$ hybridised carbon atom.

Haloarene (Aryl halide)

A compound formed by the replacement of hydrogen atom(s) in an aromatic hydrocarbon by halogen atom(s), where the halogen is attached to an $sp^2$ hybridised carbon atom of an aryl group.

Chloramphenicol

A chlorine containing antibiotic produced by microorganisms that is effective for the treatment of typhoid fever.

Thyroxine

An iodine containing hormone produced by the body, the deficiency of which causes goiter.

Chloroquine

A synthetic halogen compound used for the treatment of malaria.

Halothane

A synthetic halogen compound used as an anaesthetic during surgery.

Primary ($1^{\circ}$) Alkyl Halide

An alkyl halide where the halogen atom is attached to a primary carbon atom.

Allylic Halides

Compounds in which the halogen atom is bonded to an $sp^3$ hybridised carbon atom adjacent to a carbon-carbon double bond ($C=C$).

Benzylic Halides

Compounds in which the halogen atom is bonded to an $sp^3$ hybridised carbon atom attached to an aromatic ring.

Vinylic Halides

Compounds in which the halogen atom is bonded to an $sp^2$ hybridised carbon atom of a carbon-carbon double bond ($C=C$).

Geminal Halides (gem-dihalides)

Dihalo-compounds where both halogen atoms are present on the same carbon atom of the chain; also known as alkylidene halides.

Vicinal Halides (vic-dihalides)

Dihalo-compounds where halogen atoms are present on adjacent carbon atoms; also known as alkylene dihalides.

Finkelstein Reaction

A halogen exchange reaction where alkyl chlorides or bromides react with $NaI$ in dry acetone to prepare alkyl iodides.

Swarts Reaction

The synthesis of alkyl fluorides by heating an alkyl chloride or bromide in the presence of a metallic fluoride such as $AgF$, $Hg_2F_2$, $CoF_2$, or $SbF_3$.

Sandmeyer’s Reaction

A reaction where a primary aromatic amine is treated with sodium nitrite and cold aqueous mineral acid to form a diazonium salt, which is then mixed with cuprous chloride or bromide to replace the diazonium group.

Ambident Nucleophiles

Groups that possess two nucleophilic centres, such as cyanides ($CN^{-}$) and nitrites ($NO_2^{-}$), allowing them to link through either of the two different atoms.

$SN_2$ (Substitution Nucleophilic Bimolecular)

A single-step nucleophilic substitution reaction following second-order kinetics, characterized by the simultaneous breaking of the carbon-halide bond and formation of the carbon-nucleophile bond, resulting in inversion of configuration.

$SN_1$ (Substitution Nucleophilic Unimolecular)

A two-step nucleophilic substitution reaction following first-order kinetics, proceeding through a carbocation intermediate and often accompanied by racemisation.

Dextrorotatory ($d$-form)

An optically active compound that rotates the plane of plane polarised light to the right (clockwise), indicated by a positive ($+$) sign.

Laevo-rotatory ($l$-form)

An optically active compound that rotates the plane of plane polarised light to the left (anticlockwise), indicated by a negative ($–$) sign.

Chirality

The property of being non-superimposable on a mirror image; chiral molecules are optically active.

Enantiomers

Stereoisomers that are related to each other as non-superimposable mirror images and possess identical physical properties except for the direction of optical rotation.

Racemic Mixture

A mixture containing two enantiomers in equal proportions which has zero optical rotation, represented by the prefix $dl$ or ($\pm$).

Zaitsev Rule

A rule stating that in dehydrohalogenation reactions, the preferred product is the alkene which has the greater number of alkyl groups attached to the doubly bonded carbon atoms.

Grignard Reagents

An important class of organo-metallic compounds ($RMgX$) obtained by the reaction of haloalkanes with magnesium metal in dry ether.

Wurtz Reaction

The reaction of alkyl halides with sodium in dry ether to give hydrocarbons containing double the number of carbon atoms present in the original halide.

Phosgene (Carbonyl chloride)

An extremely poisonous gas ($COCl_2$) formed when chloroform is slowly oxidised by air in the presence of light.

Freons

Chlorofluorocarbon compounds of methane and ethane that are extremely stable, unreactive, non-toxic, and used as refrigerants and aerosol propellants.