What are the exceptions to organic chemistry from NEET



The Organic chemistry (also for short: Organics) is the study of the structure and properties of the compounds of carbon as well as their analysis and especially their production.

General

Organic chemistry includes all compounds of carbon with other elements; about 19 million are currently known and more are added every day. This also includes all the building blocks of currently known life. Also, by a long way not all organic molecules occurring in nature are known or investigated.

The counterpart is inorganic chemistry, which deals with all other elements and their compounds. A few compounds are dealt with by both organic and inorganic chemistry. B. oxalic acid and its salts (oxalates) and hydrogen cyanide and its salts (cyanides).

The special position of carbon is based on the fact that the carbon atom has four bonding electrons, which means that it can form non-polar bonds with one to four other carbon atoms. As a result, linear or branched carbon chains as well as carbon rings can arise, which are connected to hydrogen and other elements (mainly oxygen, nitrogen, sulfur, phosphorus) at the binding electrons that are not occupied by carbon, which can lead to large and very large molecules and the huge variety of organic molecules explained. There are also a large number of compounds of the likewise four-bonded silicon, but far from such a variety.

The properties of organic substances are very much determined by their respective molecular structure. Even the properties of simple organic salts such as acetates are clearly shaped by the molecular shape of the organic part. There are also many isomers, i.e. compounds with the same overall composition (molecular formula) but different structure (structural formula).

In contrast, the molecules in inorganic chemistry usually consist of only a few atoms, in which the general properties of solids, crystals and / or ions come into play. But there are also polymers that contain no carbon (or only in subgroups), e.g. B. the silanes.

Organic synthesis strategies differ from syntheses in inorganic chemistry, since organic molecules can usually be built up piece by piece.

history

In the second half of the 18th century, morphological-physiological and non-chemical considerations and characteristics led to a new classification of substances / matter. So were z. B. mineral substances as "unorganized" and animal and vegetable substances as "organized bodies". The terms “inorganic” and “organic bodies” were already in use around 1780. In 1806 the Swedish chemist Jöns Jacob Berzelius used the term “organic chemistry” for the first time (cf. Walden 1927).

As early as the 18th century there were significant numbers of organic substances has been isolated as a pure substance.

Examples are urea (1773, Hilaire Rouelle) and many acids, such as formic acid obtained from ants (1749, Andreas Sigismund Marggraf), malic acid from apples, and tartaric acid obtained from tartar (1769, Carl Wilhelm Scheele).

At first it was not possible to produce these substances in the laboratory, so that the opinion arose that they could only be produced by living beings (organisms) and that a special 'life force' (vis vitalis) was necessary for their creation.

The production of urea by heating ammonium cyanate in 1828 by Friedrich Wöhler was able to refute this assumption.

In 1857 Friedrich August Kekulé published his work "About the s. G. paired compounds and the theory of polyatomic radicals " in Liebig's Annals of Chemistry (Vol. 104, No. 2, pp. 129 ff.), Which is seen as the starting point for organic structural chemistry. In this work, carbon is described as tetravalent for the first time.

With the increasing skill of the chemists - for example in the analysis and synthesis of the types of sugar by Hermann Emil Fischer - it was possible to synthesize an increasing number of organic substances by total synthesis from inorganic basic substances.

In addition, derivatives were produced from the natural substances that do not occur in nature (such as the hydrazones and phenylhydrazones of carbohydrates).

Completely unnatural-looking substances, such as plastics and petroleum, are also organic compounds, since they consist of carbon compounds like the substances in life forms. Crude oil, natural gas and coal, the raw materials for many synthetic products, are ultimately of organic origin.

The metabolic processes occurring in living beings are now dealt with in biochemistry, which is based on organic chemistry.

Importance of organic chemistry

The most important molecules in life, including amino acids, proteins, carbohydrates, and DNA, are organic, so much of biochemistry is nothing more than organic chemistry.

This also results in great importance for biology and medicine, for example in the development and manufacture of pharmaceuticals, as well as for food chemistry.

Technically important areas of organic chemistry are petrochemicals, plastics and synthetic fibers, many adhesives, paints and varnishes.

Groups of substances in organic chemistry

There are two possibilities for a systematic classification of the individual substances in organic chemistry into groups of substances:

Classification according to functional group:

Classification according to carbon structure:

Reactions

See reaction mechanism

The reactions in organic chemistry can largely be classified into the following basic types:

In addition, many reactions are known by the name of their discoverer (please refer: Name reactions).

A classification according to the type of bond created or the building block can be found in the list of organic reactions (classification according to the bond produced).

literature

  • Hart, H .; Craine, L.E .; Hart, D.J .; Hadad, C.M .; Kindler, N .: Organic chemistry. 3rd edition Wiley-VCH, Weinheim 2007, ISBN 978-3-527-31801-8
  • Vollhardt K.P.C. and Schore N.E .: Organic chemistry. 4th edition, Wiley-VCH, Weinheim 2005, ISBN 978-3-527-31380-8
  • P. Walden: From Iatrochemistry to "Organic Chemistry". Zeitschrift für angewandte Chemie 40 (1), pp. 1-16 (1927), ISSN 0932-2132
  • Heinz A. Staab: A hundred years of organic structural chemistry. Angewandte Chemie 70 (2), pp. 37-41 (1958), ISSN 0044-8249

Categories: Subfield of Chemistry | Organic chemistry