Organic Chemistry Practice: Alkanes, Alkenes, Alkynes, and Arenes

Comprehensive vocabulary flashcards covering Alkanes, Alkenes, Alkynes, and Electrophilic Aromatic Substitution based on lecture notes.

Alkane

Branched and unbranched aliphatic saturated hydrocarbons containing only single bonds or $\sigma$ bonds.

Paraffins

A name for alkanes (derived from Parum=little, affins=reactivity) used because they do not react with reagents like acids, bases, or oxidants such as $KMnO_{4}$.

Alkane Bond Angle

The characteristic angle in the tetrahedral shape of alkanes, measured at $109^{\circ}.28'$.

$C-C$ Bond Length (Alkane)

The specific distance between carbon atoms in an alkane, measuring $1.54\,A^{\circ}$.

Sabatier and Senderens reaction

The catalytic hydrogenation of alkenes or alkynes over nickel at $200-300^{\circ}\,C$ to produce alkanes.

Raney Nickel

A catalyst obtained by boiling a $Ni/Al$ alloy with $NaOH$, resulting in nickel in a finally divided state.

Wurtz Reaction

The production of higher symmetrical alkanes by treating two moles of alkyl halide with sodium in the presence of dry ether.

Corey-House Synthesis

A preparation method suitable for both symmetrical and unsymmetrical alkanes using lithium, copper halides ($CuX$), and alkyl halides ($R'X$).

Frankland Reagent

An organozinc compound ($R_{2}Zn$) formed when zinc is used in place of sodium in a reaction with alkyl halides.

Decarboxylation

The process of eliminating carbon dioxide from a carboxylic acid, typically by heating a sodium salt of the acid with soda lime.

Soda Lime

A mixture of sodium hydroxide ($NaOH$) and quick lime ($CaO$) used in decarboxylation reactions.

Kolbe's Process

The electrolysis of a concentrated aqueous solution of sodium or potassium salts of saturated monocarboxylic acids to form alkanes.

Clemmensen Reduction

The reduction of carbonyl compounds, preferably ketones, using Zinc amalgam and concentrated $HCl$ ($Zn-Hg/HCl$).

Wolf Kishner Reaction

A reduction method for alkanals and alkanones using hydrazine ($NH_{2}NH_{2}$) and $C_{2}H_{5}OH/Na$ at $180^{\circ}\,C$ to form alkanes.

Zerewitinoff's Method

A technique using Grignard Reagents ($R-Mg-X$) to determine the number of active hydrogen atoms in a compound.

Density of Alkanes

A physical property that increases with molecular weight until it becomes constant at $0.8\,g/mL$, making all alkanes lighter than water.

Carbon Black

A product obtained from the incomplete oxidation of methane in a limited supply of air, used in printing.

Halogenation Reactivity (Halogens)

The order of reactivity for halogens in substitution reactions with alkanes: $F_{2} > Cl_{2} > Br_{2} > I_{2}$.

Halogenation Reactivity (Hydrogen)

The order of ease for replacing hydrogen atoms in alkanes: Tertiary $C-H$ > Secondary $C-H$ > Primary $C-H$.

Nitration (Alkane)

The substitution of a hydrogen atom with a $-NO_{2}$ group by reacting alkane vapors with concentrated $HNO_{3}$ at $450^{\circ}\,C$.

Sulphonation

The replacement of an alkane hydrogen atom by $-SO_{3}H$ using fuming $H_{2}SO_{4}$ or oleum ($H_{2}S_{2}O_{7}$).

Reed Reaction

Also known as chlorosulphonation, it is the reaction of an alkane with a mixture of $SO_{2}$ and $Cl_{2}$ in the presence of UV light.

Pyrolysis (Cracking)

The thermal decomposition of higher alkanes into lower hydrocarbons by heating to $500-700^{\circ}\,C$ in the absence of air.

Hydroforming

The conversion of unbranched higher alkanes (6 to 10 carbons) to aromatic hydrocarbons over oxides of $Cr$, $Mo$, or $V$ at $500^{\circ}\,C$.

Olefins

Another name for alkenes, meaning "oil forming gas," derived from their ability to form oily liquids when treated with halogens.

$C=C$ Bond Length

The distance between double-bonded carbon atoms in Ethene, measuring $1.34\,\text{…}$.

Dehydration

The preparation of alkenes from monohydric alcohols by the loss of water, catalyzed by $Al_{2}O_{3}$ or mineral acids.

Saytzeff Rule

A regioselectivity rule stating that in elimination reactions, the major alkene product is the one with the maximum number of alkyl groups on the double-bonded carbons.

Dehydrohalogenation

The removal of a hydrogen halide ($HX$) from an alkyl halide using alcoholic $KOH$ or $NaNH_{2}$ to form an alkene.

Vicinal Dihalides

Compounds where two halogen atoms are attached to adjacent carbon atoms.

Gem Dihalides

Compounds where two halogen atoms are attached to the same carbon atom.

Hoffmann's Rule

An elimination rule where the less substituted or less stable alkene is the major product, observed in the pyrolysis of esters or ammonium ions.

Cope Reaction

The pyrolysis of trialkyl amine oxides at $150^{\circ}\,C$ to form an alkene and an $-N-OH$ derivative.

Lindlar's Catalyst

Metallic palladium deposited on calcium carbonate conditioned with lead acetate and quinoline, used for the syn-addition of hydrogen to alkynes.

P-2 Catalyst

Nickel boride ($Ni_{2}B$) used for the catalytic hydrogenation of alkynes to cis-alkenes.

Birch Reduction

The reduction of alkynes to trans-alkenes using alkali metals like sodium or lithium in liquid ammonia ($NH_{3}$).

Electrophilic Addition

The characteristic reaction of alkenes where an electrophile ($E^{+}$) attacks the high electron density of the double bond.

Markovnikov Rule

A rule stating that in the addition of $HX$ to an unsymmetrical alkene, the halogen attaches to the carbon with fewer hydrogen atoms.

Peroxide Effect (Kharasch Effect)

The anti-Markovnikov addition of $HBr$ to unsymmetrical alkenes in the presence of peroxides via a free radical mechanism.

Tilden Reagent

Nitrosyl chloride ($NOCl$), which adds to alkenes to form propylene nitroso chloride.

Hydroboration

The reaction of alkenes with diborane ($B_{2}H_{6}$) in $THF$ to produce trialkyl boranes, typically used for anti-Markovnikov hydration.

Oxymercuration-demercuration

A two-step process using mercuric acetate followed by sodium borohydride to produce alcohol from an alkene according to Markovnikov's rule.

Hydroformylation (Oxo reaction)

The reaction of alkenes with carbon monoxide and hydrogen over a cobalt catalyst at high pressure to produce aldehydes.

Ozonolysis

A test for unsaturation involving the addition of ozone to a double bond followed by reductive hydrolysis to form carbonyl compounds.

Baeyer's Reagent

A 1% cold alkaline solution of $KMnO_{4}$ used to detect unsaturation by decolourising its pink colour and forming a glycol.

Waker Process

The oxidation of ethene to acetaldehyde using $H_{2}O_{2}$ in the presence of $PdCl_{2}$ and $CuCl_{2}$ catalysts.

N-Bromosuccinimide (NBS)

A reagent used for allylic bromination and benzylic substitution in alkenes and alkyl benzenes.

Ziegler - Natta Catalysts

A combination of $R_{3}Al$ and $TiCl_{4}$ used to carry out addition polymerisation via an ionic mechanism.

Teflon (PTFE)

Polytetrafluoroethylene, a polymer made from $F_{2}C=CF_{2}$ that is inert to solvents and boiling acids.

Conjugated Dienes

Dienes where two double bonds are separated by a single bond, allowing for resonance and increased stability.

Cumulated Dienes

Dienes where two double bonds are present at adjacent positions, such as in Propa-1,2-diene.

Acetylenes

A general name for alkynes, derived from the simplest member, acetylene ($C_{2}H_{2}$).

$C \equiv C$ Bond Energy

The energy required to break the triple bond in an alkyne, valued at $192\,kcal. mol^{-1}$.

Berthelot's Process

The synthesis of acetylene by striking an electric arc between carbon electrodes in the presence of hydrogen.

Westron

Acetylene tetrachloride ($CHCl_{2}CCl_{2}$), used as a solvent in cloth industries.

Westrosol

Trichloroethene ($CHCl=CCl_{2}$), obtained by treating Westron with $Ca(OH)_{2}$.

Tollen's Reagent

An ammoniacal solution of silver nitrate used to detect terminal alkynes by forming a white precipitate of silver acetylide.

Mesitylene

The aromatic product ($1,3,5-trimethylbenzene$) formed by the cyclic trimerisation of propyne through a red hot iron tube.

Electrophilic Aromatic Substitution (EAS)

The characteristic reaction of benzenoid arenes where an electrophile replaces a hydrogen atom on the aromatic ring.

Arenium Ion

A true intermediate in $EAS$ (also called a $\sigma$-complex) where the carbon bonded to the electrophile becomes $sp^{3}$ hybridized.

Nitrating Agent

A mixture used for nitration, commonly concentrated nitric acid ($HNO_{3}$) and sulphuric acid ($H_{2}SO_{4}$).

Friedel-Crafts Alkylation

The reaction of benzene with alkyl halides in the presence of a Lewis acid catalyst ($AlCl_{3}$) to yield alkyl benzenes.

Friedel-Crafts Acylation

The introduction of an acyl group ($RCO-$) into an aromatic ring using an acyl halide and a Lewis acid catalyst.

Isomerisation

The conversion of unbranched alkanes or alkenes into branched isomers using catalysts like $AlCl_{3}/HCl$ or heat.

Pyridine

A benzenoid heterocyclic aromatic compound where one carbon of the ring has been replaced by a nitrogen atom.

Huckel Rule

The $(4n + 2)\pi$ rule used to determine aromaticity in closed ring systems.

Lindane

The $\gamma$-isomer of Benzene Hexachloride ($BHC$).

Allyl Chloride

The product formed by the free radical substitution of propene with $Cl_{2}$ at $500^{\circ}\,C$.

Neoprene

A synthetic rubber formed by the polymerisation of chloroprene ($2-chloro-1,3-butadiene$).

Acetylene Hybridization

The $sp$ hybridization state of carbon atoms in an alkyne, resulting in a linear structure with a $180^{\circ}$ bond angle.