Alcodiene (Siene) and Their Properties

Vocabulary flashcards covering the classification, physical and chemical properties, oxidation reactions, and polymerization products (rubbers) of Alkadienes (Siene) as described in the lecture notes.

Alcodiene (Siene)

Hydrocarbons characterized by the presence of two $C=C$ double bonds.

Physical state of Alkadienes at room temperature

$C_4 - C_5$ are gaseous, $C_6 - C_{17}$ are liquids, and $C_{18}$ and above are solids.

Solubility of Alkadienes

They are insoluble in water but soluble in organic solvents such as $CHCl_3$ and $CS_2$.

Isoprene

The common name for 2-methyl-1,3-butadiene, which is a liquid.

Boiling points ($p.f.$) of Alcodiene

They increase with the number of Carbon atoms but are slightly lower than those of corresponding alkanes.

Cumulated dienes

Dienes where the two double bonds are consecutive ($-C=C=C-$).

Isolated dienes

Dienes where the two double bonds are separated by at least two single bonds ($C-C$).

Conjugated dienes

Dienes where the two double bonds are separated by exactly one single bond ($-C=C-C=C-$).

Reactivity order by double bond position

Cumulated dienes < Isolated dienes < Conjugated dienes.

1,4-Addition

A special addition reaction in conjugated systems where the reactant atoms attach to $C_1$ and $C_4$, and a new double bond forms between $C_2$ and $C_3$.

Partial addition (1:1)

Addition in conjugated dienes with a molar ratio of $1:1$, which can occur at positions 1-2 or 1-4.

Total addition (1:2)

Addition in conjugated dienes with a molar ratio of $1:2$, resulting in the saturation of both double bonds.

Complete oxidation (Combustion) formula

C_n H_{2n-2} + rac{3n-1}{2} O_2 ightarrow n CO_2 + (n-1) H_2O + Q

Mild oxidation of dienes

Reaction with $KMnO_4$ in neutral or slightly alkaline medium that produces a tetrol.

Energetic oxidation of dienes

Reaction involving strong oxidizing agents like $KMnO_4$ or $K_2Cr_2O_7$ in an acidic medium ($H_2SO_4$), leading to the breaking of $C=C$ bonds.

Decomposition of Oxalic Acid ($HOOC-COOH$)

In the presence of energetic oxidizing agents, this product decomposes into $2CO_{2}$ and $H_{2}O$.

Homopolymerization

The polymerization of a single type of monomer, such as butadiene, to form polybutadiene.

Polybutadiene (Buna Rubber)

A synthetic rubber formed by the 1-4 polymerization of 1,3-butadiene.

Natural Rubber

The cis-isomer of polyisoprene, which is elastic and found in the rubber tree.

Gutta-percha (GUTAPERCA)

The trans-isomer of polyisoprene, which is plastic and lacks the elasticity of natural rubber.

Copolymerization

The polymerization of two or more different monomers ($A + B$) to form a copolymer.

Buna N (Butadiene-acrylonitrile rubber)

A synthetic rubber produced by the copolymerization of 1,3-butadiene and acrylonitrile.

Buna S (Butadiene-styrene rubber)

A synthetic rubber produced by the copolymerization of 1,3-butadiene and styrene.