There are three main types of addition reactions, polar and non-polar. In organic chemistry, addition reactions, put in its most basic terms are an organic reaction. This is the process by which two or more molecules join to form a larger one. Of the polar varieties there are two main types, electrphilic and nucleophilic addition reactions. Among the varieties of the non-polar reactions is the free radical addition. Addition reactions are also specific to chemical compounds that have multiple-bonded atoms.
An electrophilic addition reaction, in organic chemistry, is an addition reaction where, in a chemical compound, a pi-bond is taken away when two new covalent bonds are created. A double bond or a triple bond must be present in the substrate of an electrophilic addition reaction. An influential vital force for this type of reaction is in the formation of an electrophile. An electrophile literally translated means ‘electron-lover’. This reagent is attracted to electrons that take part in the chemical reaction by accepting an electron pair; this allows it to bond to a nucleophile. In the electrophilic addition reaction, the electrophile forms a covalent bond with an electron rich unsaturated C=C bond. The carbon-carbon bond receives the positive charge from X.
A nucleophilic addition reaction in organic chemistry, is an addition reaction where by a chemical compound which is a pi-bond, is taken out when the formation of two new covalent bonds by addition of the nucleophilic. These types of addition reactions are specific to chemical compounds that have multiple-bonded atoms. Molecules with carbon –hetero multiple bonds like carbonyls, nitriles or imines and also molecules with carbon that are a carbon double or triple bonds. A pi-bond is a covalent chemical bonds where by two lobes of one participating electron have an orbital overlap of the two lobes of the other participating electron.
The addition-elimination reaction, which is closely matched, is an addition reaction that always followed by an elimination reaction. In most of the reactions it involves the addition of nucleophiles to carbonyl compounds; these are called nucleophilic acyl substitution. Some other addition-elimination reactions include the reaction of an alipathic amine to an imine, as well as an aromatic amine to a Schiff base in alkylimino-de-oxo-bisubstitution. Hydrolysis of nitriles to carbonyl acids is also included.
Addition reactions are also applied to addition polymerization. This is the method by which the chain growth polymerization technique where unsaturated monomer molecules add on to a growing polymer chain, one molecule at a time. There are two distinct concepts when it comes to ‘chain growth polymerization’ and ‘addition polymerisation’. Poly urethane polymizes with addition polymerization, but it’s reactant mechanism relates to a step-growth polymerization. In 1929, Wallace Hume Carothers introduced the different, unique concepts between the two methods. A polymer only is an addition, while a polymer and a molecule with low weight is condensation. The differences between ‘step-growth polymerization’ and ‘chain-growth polymerization’ were introduced in 1953 by Paul Flory. These are known as reaction mechanisms. By functional groups they are a step-growth polymerization and by free-radical or ion they are a chain-growth polymerization. |
