Information about Ester
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A phosphoric acid ester
Esters are a class of chemical compounds and functional groups. Esters consist of an inorganic or organic acid in which at least one -OH (hydroxy) group is replaced by an -O-alkyl (alkoxy) group. The most common type of esters are carboxylic acid esters (R1-C(=O)-O-R2), other esters include phosphoric acid, sulfuric acid, nitric acid, and boric acid esters. Volatile esters often have a smell and are found in perfumes, essential oils, and pheromones and give many fruits their scent. Ethyl acetate and methyl acetate are important solvents, fatty acid esters form fat and lipids, and polyesters are important plastics. Cyclic esters are called lactones. The name "ester" is derived from the German Essig-Äther (literally:vinegar ether), an old name for ethyl acetate. Esters can be synthesized in a condensation reaction between an acid and an alcohol in a reaction known as esterification.
Nomenclature
An ester is named according to the two parts that make it up: the part from the alcohol and the part from the acid (in that order), for example ethyl sulfuric acid ester.Since most esters are derived from carboxylic acids, a specific nomenclature is used for them. For esters derived from the simplest carboxylic acids, the traditional name for the acid constituent is generally retained, e.g. formate, acetate, propionate, butyrate.[1] For esters from more complex carboxylic acids, the systematic name for the acid is used, followed by the suffix -oate. For example, methyl formate is the ester of methanol and methanoic acid (formic acid): the simplest ester. It could also be called methyl methanoate.[2]
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Esters of aromatic acids are also encountered, including benzoates such as methyl benzoate, and phthalates, with substitution allowed in the name.
Physical properties
Esters participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding makes them more water-soluble than their parent hydrocarbons. However, the limitations on their hydrogen bonding also make them more hydrophobic than either their parent alcohols or parent acids. Their lack of hydrogen-bond-donating ability means that ester molecules cannot hydrogen-bond to each other, which makes esters generally more volatile than a carboxylic acid of similar molecular weight. This property makes them very useful in organic analytical chemistry: unknown organic acids with low volatility can often be esterified into a volatile ester, which can then be analyzed using gas chromatography, gas liquid chromatography, or mass spectrometry. Many esters have distinctive odors, which has led to their use as artificial flavorings and fragrances. For example:){kind=small}
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Ester synthesis
"Esterification" (condensation of an alcohol and an acid) is not the only way to synthesize an ester. Esters can be prepared in the laboratory in a number of other ways:- by transesterifications between other esters
- by Dieckmann condensation or Claisen condensation of esters carrying acidic α-protons
- by Favorskii rearrangement of α-haloketones in presence of base
- by nucleophilic displacement of alkyl halides with carboxylic acid salts
- by Baeyer-Villiger oxidation of ketones with peroxides
- by Pinner reaction of nitriles with an alcohol
Ester reactions
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Ester saponification (basic hydrolysis)
- 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 amines, producing amides.
- Phenyl esters react to hydroxyarylketones in the Fries rearrangement.
- Di-esters such as diethyl malonate react as nucleophile with alkyl halides in the malonic ester synthesis after deprotonation.
- Specific esters are functionalized with an α-hydroxyl group in the Chan rearrangement
- Esters are converted to isocyanates through intermediate hydroxamic acids in the Lossen rearrangement.
- Esters with β-hydrogen atoms can be converted to alkenes in ester pyrolysis
External links
- An introduction to esters
- Molecule of the month: Ethyl acetate and other esters
- Making an Ester A simple guide to naming and making esters, as well as the chemistry behind it.
References
Functional group |
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| Chemical class: Alcohol • Aldehyde • Alkane • Alkene • Alkyne • Amide • Amine • Azo compound • Benzene derivative • Carboxylic acid • Cyanate • Disulfide • Ester • Ether • Haloalkane • Imine • Isocyanide • Isocyanate • Ketone • Nitrile • Nitro compound • Nitroso compound • Peroxide • Phosphoric acid • Pyridine derivative • Sulfone • Sulfonic acid • Sulfoxide • Thioester • Thioether • Thiol |
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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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Inorganic chemistry is the branch of chemistry concerned with the properties and behavior of inorganic compounds. This field covers all chemical compounds except the myriad organic compounds (compounds containing C-H bonds), which are the subjects of organic chemistry.
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Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may
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ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably. In the context of databases, a single logical operation on the data is called a transaction.
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Hydroxy can refer to:
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- In chemical nomenclature, the prefix "hydroxy-" shows the presence of a hydroxyl functional group (-OH)
- An abbreviation for the medication hydroxyzine, which is commonly sold under the brand names Atarax, Ucerax, Serecid, and Vistaril.
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An alkyl is a univalent (or free) radical containing only carbon and hydrogen atoms arranged in a chain. The alkyls form a homologous series with the general formula CnH2n+1.
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In chemistry, the alkoxyl group is an alkyl group linked to oxygen thus: R-O. The range of alkoxy groups is as great, the simplest being methoxy (-OCH3). An ethoxy substituent is found in the organic compound phenetol, C6H5OCH2CH
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Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)OH, usually written -COOH or -CO2H. [1] Carboxylic acids are Bronsted acids — they are proton donors.
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Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a mineral (inorganic) acid having the chemical formula H3PO4.
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Sulfuric (or sulphuric) acid, H2SO4, is a strong mineral acid. It is soluble in water at all concentrations. It was once known as oil of vitriol, coined by the 8th-century Arabian alchemist Jabir ibn Hayyan (Geber) after his discovery of the chemical.
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The chemical compound nitric acid (HNO3), also known as aqua fortis and spirit of nitre, is an aqueous solution of hydrogen nitrate (anhydrous nitric acid). It is a highly corrosive and toxic acid that can cause severe burns.
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Boric acid, also called boracic acid or orthoboric acid or Acidum Boricum, is a mild acid often used as an antiseptic, insecticide, flame retardant, in nuclear power plants to control the fission rate of uranium, and as a precursor of other chemical compounds.
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An aroma compound, also known as odorant, aroma, fragrance, flavor, is a chemical compound that has a smell or odor. A chemical compound has a smell or odor when two conditions are met: the compound needs to be volatile, so it can be transported to the
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Perfume is a mixture of fragrant essential oils and aroma compounds, fixatives, and solvents used to give the human body, objects, and living spaces a pleasant smell.
The precise formulas of commercial perfumes are kept secret.
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Describing a perfume
The precise formulas of commercial perfumes are kept secret.
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essential oil is any concentrated, hydrophobic liquid containing volatile aroma compounds from plants, which are called aromatic herbs or aromatic plants. They are also known as volatile or ethereal
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pheromone is a chemical that triggers a natural behavioral response in another member of the same species. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology.
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fruit has different meanings depending on context. In botany, a fruit is the ripened ovary—together with seeds—of a flowering plant. In many species, the fruit incorporates the ripened ovary and surrounding tissues.
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Ethyl acetate is the organic compound with the formula CH3CH2OC(O)CH3. This colorless liquid has a characteristic, not unpleasant smell (similar to pear drops) like certain glues or nail polish removers, in which it is used.
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Methyl acetate, also known as acetic acid methyl ester or methyl ethanoate, is a clear, flammable liquid with a characteristic, not unpleasant smell like certain glues or nail polish removers.
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A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. The most common solvent in everyday life is water. Most other commonly-used solvents are organic (carbon-containing) chemicals. These are called organic solvents.
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Types of Fats in Food
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- Unsaturated fat
- Monounsaturated fat
- Polyunsaturated fat
- Trans fat
- Omega: 3, 6, 9
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Fat
Fat may refer to:- Fat, a group of compounds that are generally soluble in organic solvents and largely insoluble in water
- Adipose tissue, an anatomical term for loose connective tissue composed of adipocytes
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Lipids can be broadly defined as any fat-soluble (hydrophobic), naturally-occurring molecules. The term is more-specifically used to refer to fatty-acids and their derivatives (including tri-, di-, and monoglycerides and phospholipids) as well as other fat-soluble sterol-containing
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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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Plastic is the general term for a wide range of synthetic or semisynthetic polymerization products. They are composed of organic condensation or addition polymers and may contain other substances to improve performance or economics.
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A lactone is a cyclic ester in organic chemistry [1]. It is the condensation product of an alcohol group and a carboxylic acid group in the same molecule. The most stable structure for lactones are the 5-membered lactones (gamma-lactone) and 6-membered lactones
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Ether is the general name for a class of chemical compounds which contain an ether group — an oxygen atom connected to two (substituted) alkyl or aryl groups — of general formula R–O–R'.
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In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions.
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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]
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