Ether
| of these articles is occupied with the chemical group of materials the Ether. For the physical term of the ether, see ether (physics). |
A Ether (z. T. also: Ether) is formal one by condensation reaction of two alcohols won chemical compound.
Thatparticularly as solution and Narkosemittel most well-known Ether is Diethylether, which even often simply Ether, rare ether is called. The simplest of its connecting class is Dimethylether. Diethylether is won from ethanol with sulfuric acid. Beside the open-chain(acyclischen) Ethern exists also cyclische Ether, so for instance tetrahydrofurane. Most Ether are relatively poorly reactive and therefore often than solvents in präparativen organic chemistry are used. Since badly hydrogen bonds train Ether, the solubility takes inWater with higher Ethern fast off. In a litre loosen themselves water approx. 65 ml the well-known Diethylethers.
- <math> R_1-O-R_2< /math>
R 1 and R 2 are alkyl residue
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Alkoxy
- alkanes designates 6 trivia 7 Web on the left of [ works on] in accordance with nomenclature, whereby the group of O-R as Alkoxy substituent alkane - chain is treated. The small and/or. niederrangigere substituent of the chain R-O-R' is here the Alkoxy remainder, the larger and/or. höherrangigere substituent forms the trunk of the material name.
Accordingly the designation of geradkettiger Alkoxy alkanes runs:
The connection H 3 C-O-CH 3 sits down together from an H 3 CO substituent and the methyl remainder as trunk, whereby howeverboth remainders are equivalent. The connection Methoxymethan is called accordingly (= Dimethylether). further examples: H 3 CO CH (CH 3) 2 ⇒ 2-Methoxypropanbecause: The propane chain is höherranging as group of methyls and the Methoxy substituent binds to the 2 (and/or. ISO) Position of the propane chain.
FH 2 C-CH 2 - O-CH 2 - CH 3 ⇒ 2-Ethoxy-1-Fluoroethanbecause:Both chains are of equal length, but the fluoridated (and thus more highly substituted) remainder is höherrangig. Since the Fluoro substituent possesses also a higher rank than the oxygen bridge, is the fluoridatedC-atom the 1-Position of the trunk.
Also cyclische Ether are well-known and as cycloalkanes are regarded, with which (or several) an C-atom was replaced by an O-atom. In order to clarify this, the syllable “Oxa” is inserted at the appropriate position:
CC/\ C O ⇒ Oxacyclohexan \ / (The H-atoms bound to the C-atoms are not represented!)CC the connection is cyclisch (“cyclo”), has a chain length of 6 atoms (“hexane”) and at a position an C-atom is by an oxygen atomreplaced (“oxa”). The connection F would be accordingly | CC/\ C O \/CC the 3-Oxafluorocyclohexan (the oxygen bridge is relative to höherrangigeren Fluoro substituents in 3-Position). (The H-atoms bound to the C-atoms are not represented!)
In practicez are common for some Ether trivial names, which are based on a denomination over the oxygen bridge bound remainder and an adding of the syllable “Ether” at the end. B.: Diethylether (Ethoxyethan) or Methylethylether (Methoxyethan).
Ethersynthese
for Etherdifferent synthesis ways are possible. The probably most well-known mechanism is the Ethersynthese after Alexander W. Williamson (1824-1904, Professor. at the University college London). Here an alkali - alcoholate ( here a sodium - becomes alcoholate) brought with a halogen alkane to the reaction, whereby beside thatappropriate alkali halogen - salt the desired product, which develops for Ether:
(R = alkyl residue, hydrogen)
the Williamson Ethersynthese leads with intramolekularer reaction to cyclischen Ethern:
(did not designate atoms = alkyl residue)
the simplest representative of this class is the Oxacyclopropan, the most well-known representativethe tetrahydrofurane (THF), which is a popular solvent in organic chemistry.
further mechanisms:
- acid-catalyzed Kondesation of alcohols
under acid catalysis can be condensed two molecules alcohol to a Ether:
(R = alkyl residue)
in the case of use only a kind of alcohol can on thisAway symmetrical Ether to be represented.
- Can add addition of alcohols
at double bonds of alcohols at double bonds, whereby first the proton of the group of alcohols is added elektrophil to the double bond. Subsequently, the alcoholate deposits itself nukleophil :
(R = alkyl residue, hydrogen (evtll. Markovnikov ruleconsider))
Heteroether
beside „the normal “Ethern, thus alkyl residues with oxygen bridge, gives it also to analogues with relatives of the oxygen. In the 6. Main group follows after the oxygen the sulfur. This forms according to the rules described above in such a wayThioether mentioned. With these the oxygen bridge is replaced by a sulfur bridge. One the most well-known Thioether might be the mustard gas.
Kronenether
Kronenether are a special group of cyclischen Ethern, which earn the mention under their own keyword.Kronenether cyclische Ether, which are from together bound 1,2-Diethern, are general. The usual nomenclature of Kronenethern is unusual. One the simplest Kronenether is [12] Krone-4. Here [12] the total number of the atoms in the molecule and -4 gives the number of the oxygen atoms inMolecule on. For this there is closer information in the article Kronenether.
danger references, storage and use
in handling Ethern (all kind) it is to be particularly made certain that highly explosive peroxides form Ether with atmospheric oxygen. These can usually throughthe brown discoloration by acetic acid Iodid - solutions to be proven. In the trade special test sticks are available. The storage of Ethern for the laboratory use should take place therefore only in small bundles from maximally 1 litre by means of potassium hydroxide - Plätzchen in brown glass bottles. While handlingwith low Ethern their low boiling point and easy inflammability should be never underestimated. (Diethyl) Ether air mixtures are explosive from 2-36 Vol%. It is important that Ether steams are heavier not only colorless, but also than air. They collect themselves thus in low-convenient places. Due tothis fact and the anaesthetizing effect of Ethern are to be used Ether only in well working departures.
trivia
- the “Ether” well-known in the colloquial language designates Diethylether (C 2 H 5 - degrees of 2 H 5), one thatsimplest Ether.
- The word “Ether” originates from the Greek one (more aither, αιτηρ) and means in approximately “upper air” or “fire air”.
- Diethylether served at present the Prohibition partly than ethanol replacement (oral income) and isolated is also this very day cases of abuse well-known. The physiologicalEffect is similarly that of the alcohol and with the dismantling of the Diethylethers in the body develops among other things also for ethanol.
