Organic Chemistry - "Change", Part 2: Fundamental Reactions

 Greetings,

This post introduces the more common general reactions encountered when studying Organic Chemistry.  Three of these more common reaction types are discussed here, namely:

• Addition
• Elimination
• Substitution

Addition reactions start with an unsaturated carbon-chain compound and another entity (Binary compound or element), which adds to the chain at a double (more common) or triple bond. The product of this reaction is a saturated carbon chain compound (all single bonds) with elements added at adjacent carbon atoms (the original location(s) of the multiple bond(s)).

Elimination reactions are the opposite of addition: Starting with a saturated carbon chain, an adjacent pair of elements (or functional groups) combine leaving behind a multiple bond (double or triple) and a separate compound, formed from the leaving parts.

A substitution reaction starts with, typically, a functional group attached to the middle of a saturated carbon chain.  Another component (single element or group of elements) reacts at the site of the functional group.  The original functional group leaves the carbon chain and is replaced with a new element or functional group.

Fundamental Reactions Diagram

The diagram, below, shows general examples of the reaction types dicussed above.  The "R" components are general other parts (the "Rest") of the carbon chain.  The numbers, 1 and 2, simply mean that the "R" components are separate entities.

I would like to point out that the overall scenarios of the reactions, shown above, are more complex than they may appear to be.  Often, in Organic Chemistry reactions, other components (catalysts or other solution components (involved in the reactions)) are shown. These are indicated above the reaction "yields" arrow.  Another concept, which cannot be captured with a simple diagram, are the mechanisms of each reaction.  Mechanisms describe detailed individual reaction steps and intermediate (short-lived) entities.  Future posts will discuss the nature of Organic Chemistry Reaction Mechanisms.

That's all for this post.  As always, thank you for reading!