Information about Dehydration Synthesis
A condensation reaction is a chemical reaction in which two molecules or moieties combine to form one single molecule, together with the loss of a small molecule.[1] When this small molecule is water, it is known as a dehydration reaction; other possible small molecules lost are hydrogen chloride, methanol, or acetic acid.
A condensation reaction may be considered as the opposite of a hydrolysis reaction (the cleavage of a chemical entity into two parts by the action of water).
The synthesis of polymers, where monomers react and become covalently bonded with one another through the loss of a water molecule.
A high conversion rate is required to achieve high molecular weights as per Carothers' equation.
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. Bifunctional monomers lead to linear chains (and therefore thermoplastic polymers), but when the monomer functionality exceeds two, the product is a thermoset polymer.
Many biological transformations are condensation reactions. Polypeptide synthesis, polyketide synthesis, terpene syntheses, phosphorylation, and glycosylations are a few examples.
Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water.[1][2] This is the type of reaction that is used to break down polymers.
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The condensation of two amino acids to form a peptide bond.
A condensation reaction may be considered as the opposite of a hydrolysis reaction (the cleavage of a chemical entity into two parts by the action of water).
Mechanism
Many condensation reactions follow a nucleophilic acyl substitution or an aldol condensation reaction mechanism. Other condensations, such as the acyloin condensation are triggered by radical or single electron transfer conditions.The synthesis of polymers, where monomers react and become covalently bonded with one another through the loss of a water molecule.
Condensation reactions in polymer chemistry
In polymer chemistry, a series of condensation reactions take place whereby monomers or monomer chains add to each other to form longer chains. This may also be termed as 'condensation polymerization' or 'step-growth polymerization'. It occurs either as a homopolymerization of an A-B monomer or a polymerization of two co-monomers A-A and B-B. Small molecule condensates are usually liberated, unlike in polyaddition where there is no liberation of small molecules.A high conversion rate is required to achieve high molecular weights as per Carothers' equation.
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. Bifunctional monomers lead to linear chains (and therefore thermoplastic polymers), but when the monomer functionality exceeds two, the product is a thermoset polymer.
Applications
This type of reaction is used as a basis for the making of many important polymers for example: nylon, polyester and other condensation polymers and various epoxies. It is also the basis for the laboratory formation of silicates and polyphosphates. The reactions that form acid anhydrides from their constituent acids are typically condensation reactions. Other organic condensation reactions are Aldol condensations, self-condensation, the acyloin condensation and the benzoin condensation.Many biological transformations are condensation reactions. Polypeptide synthesis, polyketide synthesis, terpene syntheses, phosphorylation, and glycosylations are a few examples.
References
1. ^ International Union of Pure and Applied Chemistry (1994). "Condensation Reaction". Compendium of Chemical Terminology Internet edition.
chemical reaction is a process that results in the interconversion of chemical substances.[1] The substance or substances initially involved in a chemical reaction are called reactants.
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molecule is defined as a sufficiently stable electrically neutral group of at least two atoms in a definite arrangement held together by strong chemical bonds.[1][2] In organic chemistry and biochemistry, the term molecule
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In organic chemistry, functional groups (or moieties) are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules.
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dehydration reaction is usually defined as a chemical reaction that involves the loss of water from the reacting molecule. Dehydration reactions are a subset of elimination reactions.
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hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry.
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Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH.
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Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. Its structural formula is represented as CH3COOH.
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- :Not to be confused with electrolysis
Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water.[1][2] This is the type of reaction that is used to break down polymers.
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Nucleophilic acyl substitution describes the substitution reaction involving nucleophiles and acyl compounds. Acyl compounds are carboxylic acid derivatives including esters, amides and acid halides.
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An Aldol condensation is an organic reaction in which an enolate ion reacts with a carbonyl compound to form a β-hydroxyaldehyde or β-hydroxyketone, followed by dehydration to give a conjugated enone.
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In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs.
Although only the net chemical change is directly observable for most chemical reactions, experiments can often be designed that suggest the
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Although only the net chemical change is directly observable for most chemical reactions, experiments can often be designed that suggest the
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Acyloin condensation is a reductive coupling of two carboxylic esters using metallic sodium to yield an α-hydroxyketone, also known as an acyloin. [1] [2]
The reaction is most successful when R is aliphatic and inert.
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The reaction is most successful when R is aliphatic and inert.
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radicals (often referred to as free radicals) are atomic or molecular species with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly reactive, so radicals are likely to take part in chemical reactions.
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A one-electron reduction in organic chemistry involves the transfer of an electron from a metal to an organic substrate. It serves to differentiate between true organic reductions and other reductions such as hydride transfer reactions that actually involve two-electron species.
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In step-growth polymerization, the Carothers equation (or Carothers' equation) gives the number-average degree of polymerization, Xn, for a given fractional monomer conversion, p.
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polymer is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. The word is derived from the Greek, πολυ, polu, "many"; and μέρος, meros,
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Nylon is a generic designation for a family of synthetic polymers first produced on February 28, 1935 by Wallace Carothers at DuPont. Nylon is one of the most common polymers used as a fiber.
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Polyester (aka Terylene) is a category of polymers which contain the ester functional group in their main chain. Although there are many forms of polyesters, the term "polyester" is most commonly used to refe'Bold text'Bold text'Bold text
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Condensation polymers are any class of polymers formed through a condensation reaction, releasing a small molecule by-product such as water or methanol, as opposed to addition polymers which involve the reaction of unsaturated monomers.
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In chemistry, epoxy or polyepoxide is a thermosetting epoxide polymer that cures (polymerizes and crosslinks) when mixed with a catalyzing agent or "hardener". Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A.
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silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. This definition is broad enough to include species such as hexafluorosilicate ("fluorosilicate"), [SiF6]2−
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Polyphosphates are phosphate polymers linked between hydroxyl groups and hydrogen atoms. The polymerization that takes place is known as a condensation reaction. Phosphate chemical bonds are typically high-energy covalent bonds, which means that energy is available upon breaking
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In chemistry, an anhydride is a compound that can be considered as derived from another compound by subtracting the molecules of water.
For example:
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For example:
- 2 NaOH - H2O = Na2O
- H2SO4 - H2
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An Aldol condensation is an organic reaction in which an enolate ion reacts with a carbonyl compound to form a β-hydroxyaldehyde or β-hydroxyketone, followed by dehydration to give a conjugated enone.
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Self-condensation is an organic reaction in which a chemical compound containing a carbonyl group acts both as the electrophile and the nucleophile in an aldol condensation.
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Acyloin condensation is a reductive coupling of two carboxylic esters using metallic sodium to yield an α-hydroxyketone, also known as an acyloin. [1] [2]
The reaction is most successful when R is aliphatic and inert.
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The reaction is most successful when R is aliphatic and inert.
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The Benzoin condensation is a condensation reaction between two aromatic aldehydes, especially benzaldehyde that is catalyzed by a cyanide. The reaction product is an aromatic acyloin with benzoin as the parent compound [1].
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Protein biosynthesis (synthesis) is the process in which cells build proteins. The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process, beginning with amino acid synthesis and transcription which are then used for translation.
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Polyketides are secondary metabolites from bacteria, fungi, plants, and animals. Secondary metabolites seem to be unnecessary for an organism’s ontogeny, but appear to have applications such as defence and intercellular communication.
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Terpenes are a large and varied class of hydrocarbons, produced primarily by a wide variety of plants, particularly conifers, though also by some insects such as swallowtail butterflies, which emit terpenes from their osmeterium.
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