Organic Chemistry: Alkanes, Alkenes, and Alkynes Lecture Notes

Flashcards covering the chemical properties, preparation methods, and physical characteristics of alkanes, alkenes (olefins), and alkynes based on organic chemistry lecture notes.

Nitration of Paraffin

A process where alkanes react with nitric acid vapour at about $300^{\circ}C$ to yield nitro alkanes containing the $-C-NO_2$ or $-CNO_2$ group.

Sulphonation of alkanes

The reaction of hexane and higher alkanes with oleum to yield sulphonic acid containing the $-C-SO_3OH$ or $-C-SO_3H$ group.

Sulphonyl Chloride Conversion

The photochemical reaction of alkanes with sulphuryl chloride ($SO_2Cl_2$) in the presence of light to form sulphonyl chloride, which can be hydrolysed to sulphonic acid.

Alkenes (Olefins)

Hydrocarbons named after the corresponding alkane by replacing the ending "-ane" with "-ene," having the general formula $C_nH_{2n}$.

Unsaturation

A term referring to the presence of a double bond within a molecule, as seen in the alkene series.

Ethylene Preparation from Alcohols

Obtained by the elimination of $H_2O$ from ethanol by heating to $160^{\circ}C$ with excess concentrated sulphuric acid or by passing ethanol vapour over heated alumina ($Al_2O_3$).

Elimination from Vicinal Dihalide

The production of ethylene by heating ethylene bromide (carrying two halogen atoms on adjacent carbons) with zinc dust ($Zn$ dust).

Claisen's Reaction

A variant of aldol condensation involving reactions in the presence of aqueous ethanolic alkali, such as benzaldehyde reacting with acetaldehyde to form cinnamic aldehyde.

Hydrogenation of Alkenes

The addition of hydrogen to an olefinic double bond in the presence of a metallic catalyst such as $Pt$ or $Ni$.

Alkyl bisulphate Formation

Occurs when $98\%$ sulphuric acid ($H_2SO_4$) absorbs an olefin.

Halohydrins

Compounds such as chlorohydrins and bromohydrins formed when hypochlorous ($HOCl$) or hypobromous ($HOBr$) acids add to olefinic double bonds.

Oxidation of Alkenes to Glycols

The conversion of an olefin, such as ethylene, into a dihydric alcohol (ethylene glycol) using aqueous $KMnO_4$ and $Na_2CO_3$.

Ozonolysis

The fission of olefins by treatment with $O_3$ in the presence of chloroform to form unstable ozonides, followed by warming with water to yield carbonyl products and hydrogen peroxide.

Polymerisation

The combination of a number of molecules of a single substance (monomer) to form a product (polymer) whose molecular weight is an integral multiple of the parent substance.

Hot Chlorination

A substitution reaction occurring at about $450^{\circ}C$ where propylene (propene) is treated with chlorine to obtain allyl chloride ($CH_2Cl-CH=CH_2$).

Thermal Cracking

A technical production method for olefins involving heating long-chain paraffins ($C_{14}-C_{18}$) to about $600^{\circ}C$ in a tube packed with silica chips.

Alkynes (Acetylenic Triple Bond)

A homologous series of hydrocarbons (monoacetylenes) with the general formula $C_nH_{2n-2}$ and the systematic suffix "-yne."

Acetylene (Ethyne)

The first member of the alkyne series, represented by the formula $HC \equiv CH$.

Acetylene Cylinder Storage

Because liquid or compressed gaseous acetylene can detonate under shock, it is stored in cylinders packed with porous material soaked in acetone to increase solubility and safety.

Two-fold Addition Reaction

An experimental evidence for the triple bond in alkynes, where two successive pairs of univalent groups add to yield first an ethylenic compound and then an alkane.