| Revision as of 17:23, 23 January 2014 editZombiedeity (talk | contribs)22 editsm often -> commonly← Previous edit | Revision as of 10:19, 3 November 2014 edit undo94.136.227.226 (talk) ←Replaced content with 'i like cats'Tag: blankingNext edit → | ||
| Line 1: | Line 1: | ||
| i like cats | |||
| ]s to form a ] (red) with expulsion of water (blue)]] | |||
| A '''condensation reaction''', also commonly referred to as dehydration synthesis, is a ] in which two ]s or moieties (]) combine to form a larger molecule, together with the loss of a small molecule.<ref name="Gold">{{GoldBookRef|title=Condensation Reaction|file=C01238|year=1994}}</ref> Possible small molecules lost are ], ], ], or ] but most commonly in a biological reaction it is ]. The word "condensation" suggests a process in which two or more things are brought "together" (Latin "con") to form something "dense", like in condensation from gaseous to liquid state of matter; this does not imply, however, that condensation reaction products have greater density than reactants. | |||
| When two separate molecules react, the condensation is termed ]. A simple example is the condensation of two ]s to form the ] characteristic of ]. This reaction example is the opposite of ], which splits a chemical entity into two parts through the action of the polar water molecule, which itself splits into ] and ] ions. Hence energy is released. | |||
| If the union is between atoms or groups of the same molecule, the reaction is termed ] condensation, and in many cases leads to ring formation. An example is the ], in which the two ] groups of a single diester molecule react with each other to lose a small ] molecule and form a β-ketoester product. | |||
| ] | |||
| ==Mechanism== | |||
| Many condensation reactions follow a ] or an ] ]. Other condensations, such as the ] are triggered by ] or ] conditions. | |||
| ==Condensation reactions in polymer chemistry== | |||
| In one type of polymerization reaction, a series of condensation steps take place whereby ]s or monomer chains add to each other to form longer chains. This is termed 'condensation polymerization' or ']', and occurs for example in the synthesis of ]s or ]s. It may be either a homopolymerization of a single monomer A-B with two different end groups that condense or a ]ization of two co-monomers A-A and B-B. Small molecules are usually liberated in these condensation steps, in contrast to ] reactions with no liberation of small molecules. | |||
| In general, condensation polymers form more slowly than addition polymers, often requiring heat. They are generally lower in molecular weight. Monomers are consumed early in the reaction; the terminal functional groups remain active throughout and short chains combine to form longer chains. A high conversion rate is required to achieve high molecular weights as per ]. | |||
| Bifunctional monomers lead to linear chains (and therefore ] polymers), but, when the monomer ] exceeds two, the product is a ] chain that may yield a ] polymer. | |||
| ==Applications== | |||
| This type of reaction is used as a basis for the making of many important ]s, for example: ], ], and other ]s and various ]. It is also the basis for the laboratory formation of ]s and ]s. The reactions that form acid ]s from their constituent acids are typically condensation reactions. | |||
| Many biological transformations are condensation reactions. ], ] synthesis, ] syntheses, ], and ]s are a few examples of this reaction. | |||
| A large number of such reactions are used in synthetic organic chemistry. Other examples include: | |||
| *] | |||
| *] | |||
| *] (this is not technically a condensation, but is called so for historical reasons)<ref name="Gold"/> | |||
| *] | |||
| *] | |||
| *] (glycidic ester condensation) | |||
| *] | |||
| *] | |||
| *] | |||
| *] | |||
| *] | |||
| *] | |||
| *] or symmetrical aldol condensation | |||
| *] | |||
| See ] | |||
| ==See also== | |||
| * ] | |||
| * ] | |||
| * ]s | |||
| ==References== | |||
| {{Reflist}} | |||
| ] | |||
| ] | |||
| ] | |||
Revision as of 10:19, 3 November 2014
i like cats