Unit 4.1 & 4.2 benzene and isomerism

It must promote an electron from 2s² to 2p³

An electron orbital overlap between 2 in-plane orbits (The hotdog)

An electron orbital overlap between 2 out-of-plane orbits (The buns)

A molecule with the same molecular formula, same structural formula, but a different arrangement of atoms in 3D space

A central carbon atom with 4 different groups bonded to it

NH₂

By either -amine or amino-

A hydrocarbon with both an amine group and a carboxylic acid group

An amino acid where both the amine and the carboxylic groups are bonded to the same carbon

With an asterisk

Levorotatory and dextrorotatory (L and D)

By passing plane polarised light through a sample. The plane of polarisation will be rotated in opposite directions depending on whether the sample is L or D

An electrophile (a molecule with a region of positive charge) is attracted to a region of high electron density such as a C=C bond

An organic ion containing a positively charged carbon atom formed as an intermediate during a reaction

tertiary > secondary > primary

Secondary carbocations are more stable as there are more surrounding carbons which may shuttle electrons to stabilise the charge, whereas primary carbocations only have one adjacent carbon, which isn't enough to support the positive charge

Secondary products, as the secondary carbocation is stable enough to exist for long enough for the reaction to occur

A chiral centre

A 50:50 mixture is a formed, also known as equimolar, or a racemic mixture.

-Biologically: Using enzymes to breakdown one whilst leaving the other, then separating using traditional methods
-Chemically: Reacting the molecule with another chiral molecule, then separating using traditional methods

A ring shaped hydrocarbon with the formula C₆H₆, it is the simplest aromatic compound

An aromatic hydrocarbon (one containing benzene)

The enthalpy change from the hydrogenation of benzene is less then 3 times that of cyclohexene

Each carbon forms 3 sigma bonds (2 C-C and a C-H), with the remaining orbitals forming a toroidal cloud of delocalised pi electrons above and below the plane

The delocalised pi electron cloud provides additional stability

Electrophilic substitution

Wheland's intermediate

One (or more) of the hydrogen atoms on the benzene ring is replaced by a nitro group, NO₂, through electrophilic substitution

Concentrated sulphuric acid and nitric acid (H₂SO₄ + HNO₃)

Multiple nitration events occur per molecule, forming di-nitro and tri-nitro molecules

A catalyst used to make an electrophillic halogen (a halogen cation)

A dynamic equilibrium (AlCl₃ + Cl₂ ⇌ AlCl₄⁻ + Cl⁺)

To provide the halogen cations (the electrophiles)

The difference between the expected energy level of a molecule and the observed energy

An alkane with a missing hydrogen (methyl, ethyl, ... )

The addition of an alkyl group on to a molecule

The addition of an aldehyde

The benzene is reacted with a chloroalkane in the presence of an aluminium chloride catalyst

The benzene is reacted with an acid chloride in the presence of a halogen carrier

The reaction of the chloroalkane with AlCl₃

By the AlCl₄⁻, forming HCl

-There is no region of low electron density due to the electronegativity of chlorine, as the delocalised pi-electron cloud stabilises the dipole
- The chlorine-carbon bond is stronger than expected due to the overlap of the Cl p-orbitals with the pi-electron cloud (Haribo dummy)

An alkylated benzene where the side chain is 1 smaller than the original chloroalkane, with a methyl group in position 1

Benzene is water insoluble as the only interactions it can form are induced dipole-temporary-dipole interactions