Monday, 11 March 2013

Organic Chemistry about Ester


ESTER

Odor is a product innovated for both men and women to make them cool, sexy, and fresh. Over the past decades people are going to be crazy to search and get methods to get perfume .Perfumes are known as ester. And here we are going to introduce one of the great inventions in the organic chemistry field.  What are esters?

Esters are chemical compounds consisting of a carbonyl adjacent to an ether linkage. They 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.with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group, and most commonly from carboxylic acids and alcohols. That is, esters are formed by condensing an acid with an alcohol.

A common ester - ethyl ethanoate



Ethyl acetate is one of the carboxylic acid esters. Carboxylic acid esters are among the most pleasant-smelling organic compounds. They contribute to the flavours and fragrances of fruits and flowers.  Many are excellent solvent and reaction intermediates.  And the common esters are volatile liquids.The name of an ester contains two parts, the first part is the 'alcohol part' and the second part is the 'acid part'.For ethyl acetate, the IUPAC name is ethyl ethanoate.  'Ethyl' is the 'alcohol part' while 'ethanoate' is the 'acid part'.  The name ethyl acetate is only the name based on the common name for the acid, and the common name of ethanoic acid is the acetic acid.The most commonly discussed ester is ethyl ethanoate. In this case, the hydrogen in the -COOH group has been replaced by an ethyl group.

Esterification of carboxylic acids
The common way is the Fischer esterification, which involves treating a carboxylic acid with an alcohol in the presence of a dehydrating agent:

The equilibrium constant for such reactions is about 5 for typical esters, e.g., ethyl acetate. The reaction is slow in the absence of a catalyst. Sulfuric acid is a typical catalyst for this reaction. Many other acids are also used such as polymeric sulfonic acids. Since esterification is highly reversible, the yield of the ester can be improved using Le Chatelier's principle:
·        using the alcohol in large excess (i.e., as a solvent)
·        using a dehydrating agent: sulfuric acid not only catalyzes the reaction but sequesters water (a reaction product). Other drying agents such as molecular sieves are also effective.
·        removal of water by physical means such as distillation

Ethanoic acid reacts with ethanol in the presence of concentrated sulphuric acid as a catalyst to produce the ester, ethyl ethanoate. The reaction is slow and reversible. To reduce the chances of the reverse reaction happening, the ester is distilled off as soon as it is formed  .

List of other Ester



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  1. alfachemistry20 October 2018 at 14:53

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Organic Chemistry in Modern Life

At first glance, the term "organic chemistry" might sound like something removed from everyday life, but this could not be further from the truth. The reality of the role played by organic chemistry in modern existence is summed up in a famous advertising slogan used by E. I. du Pont de Nemours and Company : "Better Things for Better Living Through Chemistry."



Often rendered simply as "Better Living Through Chemistry," the advertising campaign made its debut in 1938, just as du Pont introduced a revolutionary product of organic chemistry: nylon, the creation of a brilliant young chemist named Wallace Carothers (1896-1937). Nylon, an example of a polymer, started a revolution in plastics that was still unfolding three decades later, in 1967. That was the year of the film The Graduate , which included a famous interchange between the character of Benjamin Braddock (Dustin Hoffman) and an adult named Mr. McGuire (Walter Brooke):


  • Mr. McGuire: I just want to say one word to you… just one word.
  • Benjamin Braddock: Yes, sir.
  • Mr. McGuire: Are you listening?
  • Benjamin Braddock: Yes, sir, I am.
  • Mr. McGuire: Plastics.


The meaning of this interchange was that plastics were the wave of the future, and that an intelligent young man such as Ben should invest his energies in this promising new field. Instead, Ben puts his attention into other things, quite removed from "plastics," and much of the plot revolves around his revolt against what he perceives as the "plastic" (that is, artificial) character of modern life.


In this way, The Graduate spoke for a whole generation that had become ambivalent concerning "better living through chemistry," a phrase that eventually was perceived as ironic in view of concerns about the environment and the many artificial products that make up modern life. Responding to this ambivalence, du Pont dropped the slogan in the late 1970s; yet the reality is that people truly do enjoy "better living through chemistry"—particularly organic chemistry.


Definition of organic chemistry


Organic chemistry is the study of carbon and the study of the chemistry of life. Since not all carbon reactions are organic, another way to look at organic chemistry would be to consider it the study of molecules containing the carbon-hydrogen (C-H) bond and their reactions.


Significance of organic chemistry


Organic chemistry is important because it is the study of life and all of the chemical reactions related to life. Several careers apply an understanding of organic chemistry, such as doctors, veterinarians, dentists, pharmacologists, chemical engineers, and chemists. Organic chemistry plays a part in the development of common household chemicals, foods, plastics, drugs, fuels... really most of the chemicals part of daily life.


Importance of organic Chemist


An organic chemist is a chemist with a college degree in chemistry. Typically this would be a doctorate or master's degree in organic chemistry, though a bachelor's degree in chemistry may be sufficient for some entry level positions. Organic chemists usually conduct research and development in a laboratory setting. Projects that would use organic chemists would include development of a better painkilling drug, formulating a shampoo that would result in silkier hair, making a stain resistant carpet, or finding a non-toxic insect repellent.