Information About ™Ester |
| CATEGORIES ABOUT ESTER | |
| functional groups | |
| esters | |
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In Chemistry , esters are Organic Compound s in which an Organic Group (symbolized by '''R'''' in this article) replaces a Hydrogen Atom (or more than one) in an Oxygen Acid . An oxygen acid is an acid whose Molecule has an '''-''' Group from which the hydrogen (H) can Dissociate as an H+ Ion . The most common esters are the carboxylate esters, where the acid in question is a Carboxylic Acid . For example, if the acid is Acetic Acid , the ester is called an Acetate . Esters may also be formed with Inorganic acids; for example, Dimethyl Sulfate is an ester, and sometimes called " Sulfuric Acid , di Methyl ester". Esters are named similarly to Salt s; although they don't really have Cation s and Anion s, the terminology follows the same pattern: a more electropositive part followed by a more electronegative part. An ester can be thought of as a product of a Condensation Reaction of an acid (usually an Organic Acid ) and an Alcohol (or Phenol compound), although there are other ways to form esters. Condensation is a type of Chemical Reaction in which two Molecule s with -OH groups are joined with eliminating a Water Molecule from their -OH groups. A condensation reaction to form an ester is called Esterification . Esterification can be catalysed by the presence of H+ ions. Sulfuric acid is often used as a Catalyst for this reaction. The name ester is derived from the German '''Es'''sig-Ä'''ther''', an old name for acetic acid ethyl ester ( Ethyl Acetate ). NAMING OF ESTERS Esters can be produced by an and Butyric Acid yields the ester Methyl Butyrate C3H7-COO-CH3 (as well as water). The simplest ester is H-COO-CH3 ( Methyl Formate , also called methyl methanoate). For esters derived from the simplest carboxylic acids, the traditional names are recommended by IUPAC, IUPAC parent groups using traditional names ''viz'', formate, acetate, propionate, butyrate, though out of these only acetate may carry further substituents. For esters from higher acids, the alkane name with an ''-oate'' ending is generally preferred, e.g., hexanoate. Common esters of aromatic acids include Benzoate s such as Methyl Benzoate , and Phthalates , with substitution allowed in the name. PHYSICAL PROPERTIES Esters participate in , Gas Liquid Chromatography , or Mass Spectrometry . Many esters have distinctive odors, which has led to their widespread use as artificial flavorings and fragrances. For example: : Methyl Butyrate smells of Pineapple or Apple : Methyl Salicylate ( Oil Of Wintergreen ) smells of the ointments called Germolene™ and Ralgex™ in the UK : Methyl Benzoate smells of fruity- Ylang Ylang : Ethyl Acetate smells of Nail Polish Remover : Ethyl Formate smells of Rum : Ethyl Butyrate smells of Pineapple or Strawberry : Ethyl Salicylate smells of Oil Of Wintergreen : Ethyl Heptanoate smells of Grape : Propyl Isobutyrate smells of Rum : Isobutyl Formate smells of Raspberries : Butyl Butyrate smells of Pineapple : Pentyl Acetate smells of Banana : Pentyl Pentanoate smells of Apple : Pentyl Butyrate smells of Pear or Apricot : Isopentyl Acetate smells of Pear or Banana (it is used as the flavouring in the manufacturing of old fashioned Pear Drops ) : Octyl Acetate smells of Fruity-orange aka a lemon cleaner.. : Benzyl Acetate smells slightly of Jasmine ESTER SYNTHESIS Esters can be prepared in the laboratory in several ways:
ESTER REACTIONS Esters may undergo Hydrolysis - the breakdown of an ester by water. This process can be catalyzed both by acids and bases. The base-catalyzed process is called Saponification . The hydrolysis yields an alcohol and a Carboxylic Acid or its Carboxylate Salt . Esters also react if heated with primary or secondary Amine s, producing Amide s. Phenyl esters react to hydroxyarylketones in the Fries Rearrangement . Specific esters undergo the Chan Rearrangement and the Lossen Rearrangement . EXTERNAL LINKS
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