Organic+-+Esterification

 Esters are derived from carboxylic acids. A carboxylic acid contains the -COOH group, and in an ester the hydrogen in this group is replaced by a hydrocarbon group of some kind. We shall just be looking at cases where it is replaced by an alkyl group, but it could equally well be an aryl group (one based on a benzene ring).
 * __What are esters?__ **

The most commonly discussed ester is ethyl ethanoate. In this case, the hydrogen in the -COOH group has been replaced by an ethyl group. The formula for ethyl ethanoate is: Notice that the ester is named the opposite way around from the way the formula is written. The "ethanoate" bit comes from ethanoic acid. The "ethyl" bit comes from the ethyl group on the end.
 * A common ester - ethyl ethanoate **

 Esters are produced when carboxylic acids are heated with alcohols in the presence of an acid catalyst. The catalyst is usually concentrated sulphuric acid. Dry hydrogen chloride gas is used in some cases, but these tend to involve aromatic esters. The esterification reaction is both slow and reversible. The equation for the reaction between an acid RCOOH and an alcohol R'OH (where R and R' can be the same or different) is: So, for example, if you were making ethyl ethanoate from ethanoic acid and ethanol, the equation would be:
 * __Making esters from carboxylic acids and alcohols__ **
 * The chemistry of the reaction **

The information is from []

[|www.ausetute.com.au/esters.html]
 * Esters and Esterification Tutorial **

1. Physical State : Lower molecular weighted esters are colourless volatile liquids. Higher esters are colourelss waxy solids. 2. Odour : All esters have a strong fruity smell. 3. Solubility : Lower members of esters are soluble in water. The solubility decreases with increase in molecular weight of the esters. Esters are soluble in organic solvents. Esters themselves are good organic solvents. 4. Acidic nature : Esters are neutral to litmus tests. Chemical Properties ** Hydrolysis of esters : Esters break down into their respective organic acid and alcohol from which they are formed. This process is called hydrolysis. When sodium hydroxide is added to an ester, say for example to ethyl ethanoate, a salt sodium ethanoate is formed along with ethyl alcohol. The reaction is shown below.
 * Properties of esters **
 * Physical Properties **
 * 



Hydrolysis of ester with an alkaline solution like sodium hydroxide is known as saponification (soap making). This reaction is used in the preparation of soaps. The above reaction is a test for checking if esters are present in any solution. Few drops of indicator phenolphthalein is added to a solution of ester and NaOH. The solution shows pink colouration. Heat the solution. When the ester has reacted completely the pink colour will disappear.
 * ** Uses of organic acids ** ||


 * * Esters are used as artificial perfumes or scents as they emit a sweet smell.
 * Esters are used in making artificial food flavours that are added in many edible items like ice creams, soft drinks, sweets, etc.
 * Esters are used as industrial solvents for making cellulose, fats, paints and varnishes.
 * Esters are used as solvents in pharmaceutical industries.
 * Esters are used as softeners in plastic industries and molding industries ||

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