Alkene is a double bond containing hydrocarbon compound. Since the hydrocarbon compounds can be short or long chained, the double bond's position could be anywhere along the hydrocarbon chain.
The double bond's position on an alkene can reveal different substitution patterns- mono, di, tri, tetra substituted alkenes.
The nomenclature is mainly used for sp3 hybridized Carbon of an alkane. The Carbon of alkyl halides, alcohols, carbocations, and the Nitrogen of amides and amines are classified by this method.
The stability order of different alkene substitution patterns is measured by comparing their heat of hydrogenations (denoted as ∆Ho) in kJ/mole or kcal/mol.
It is easy to identify the simplest aromatic hydrocarbon Benzene that is made of only two atoms- Carbon and hydrogen. Benzene is a planar, cyclic ring molecule with six sides. It has an alternating double bond that contributes to its extra stability by endowing it with resonance, a phenomenon of electron delocalization. The molecular formula of Benzene is C6H6 and the structure is-
A Haloalkane is the Halogen derivative of an alkane obtained by replacing of one or more hydrogen atoms.
For example, when one Hydrogen of an alkane, Methane, is replaced with a Halogen, for instance, Chlorine, the haloalkane obtained is chloromethane.
Alkane Haloalkane
The drawbacks of Friedel Craft Alkylation, such as polyalkylation and rearrangements, are overcome by FC Acylation Reaction.
Branched alkyl chlorides (20 or 3o) cannot be used as a reagent in FC acylation reaction. The branched alkyl chlorides on forming acylium ion undergo the loss of CO to create a stable alkyl cation. The 20 or 3o alkyl cation reacts with benzene to form alkyl benzene.
A halogen derivative of an alkane is called a Haloalkane, where the hydrogen is replaced with a halogen.
The common or the trivial name is Alkyl Halide.
A fun mnemonic to remember a few common preparation methods of haloalkane is hidden in the common name.
Pre-requisite Reading: Identifying single bond, double bond, triple bond, saturation, and unsaturation.
The DBE calculation uses the general molecular formula to find the presence of unsaturation in a compound. The unsaturation is calculated in levels or degrees. The lowest degree of unsaturation (DOU) indicates minimum unsaturation; there is the least loss of hydrogens to form pie bonds or cyclic rings like in cycloalkanes.