Ethers Nomenclature

What are Ethers?

Ethers belong to the class or group of organic compounds with having an ether group comprising an oxygen atom connected to either two alkyl or aryl groups. The general formula of ethers is R-O-R′, Ar-O-Ar, or R-O-Ar, where R and R′ represent either alkyl or aryl groups. Ethers have a similar structure to that of alcohol, whereas both Ethers and Alcohols have a similar structure to that of water.

One hydrogen atom of a molecule of water is replaced by an alkyl group in alcohol, whereas coming to the ether, both the hydrogen atoms are replaced either by alkyl or aryl groups.

Ethers Classifications

Let us now discuss the ethers classifications. Based on their attached substituent groups, ethers can be classified into two categories, generally. They are listed below.

  • Symmetrical Ethers

If two identical groups are attached to either side of an oxygen atom, then it is referred to as symmetrical ethers. These are also known as Simple Ethers.

Examples are diethyl ether, dipropyl ether, dimethyl ether, and more.

  • Asymmetrical Ethers

If two different groups are attached to either side of an oxygen atom, it is said to be asymmetrical ethers. These are also known as Mixed Ethers.

Examples are methyl phenyl ether, ethyl methyl ether, and more.

The majority of the compounds having a similar structural formula were known by different names earlier, depending on the regions they were synthesized. Such a naming system was very trivial since it raised a big confusion. Ultimately, a common naming system enlisting standard rules was introduced by IUPAC (The International Union for Pure and Applied Chemistry) for the compounds naming. This method of naming is known as an IUPAC naming or IUPAC nomenclature of ethers. 

Ether Nomenclature

The nomenclature of ethers rotates around two standard ways of naming, which are given below.

  • Common nomenclature of ethers

  • IUPAC nomenclature of ethers

Nomenclature of Ethers Rules

  • The common ether nomenclature follows the rule of naming different alkyl/aryl groups that are attached in alphabetical order to the oxygen atom on either side and adding the word ether to it finally.

For example, naming CH3OC6H5 is given by “Methyl phenyl ether.”

  • The oxygen atoms of ethers are attached to the same group on either side are named using Greek numerical prefixes like “di.” Ethers of these kinds are named by adding the suffix “di” before the aryl/alkyl groups, attached to the oxygen atom.

For example, CH3OCH3 is named as “Dimethyl ether.”

  • Ethers IUPAC nomenclature of ethers follows various guidelines. As per the IUPAC naming, a substituent group having more carbon atoms is chosen as parent hydrocarbon. Whereas, the other substituent group attached to the same oxygen atom is named by using a prefix “oxy.”

For example, CH3OC2H5 is named as “1-methoxy ethane.”

Common Nomenclature of Ethers

Ethers common names simply give the two alkyl group names bonded to oxygen and add the word “ether.” As a current practice, it is to list the alkyl groups in alphabetical order (t-butyl methyl ether), but often, older names list the alkyl groups in increasing order of size (methyl t-butyl ether). Just, if one alkyl group is described in the name, it represents two identical groups, like in ethyl ether for diethyl ether.

The ether IUPAC name (systematic) uses a smaller group named as an alkoxy substituent and the more complex group as the root name, with the oxygen atom. The above-given examples are methoxyethane (methyl-ethyl-ether), ethoxyethane (diethyl-ether), 2-methoxy-2-methylpropane (MTBE), and phenoxybenzene (diphenyl-ether). The IUPAC nomenclature of ether works better for the compounds with additional functional groups, because the other functional groups can describe in the root name.

The nomenclature of ethers examples is given below.

According to the formula R1–O–R2, ethers are the compounds having two alkyl or aryl groups bonded to an oxygen atom. The functional group of ether does not have a characteristic IUPAC nomenclature suffix, so it is required to indicate it as a substituent. So as to make it, the common alkoxy substituents are given names derived from their alkyl component, as tabulated below.

IUPAC Nomenclature of Ethers

Alkyl Group - Name

Alkoxy Group - Name

CH3 - Methyl

CH3O - Methoxy

CH3CH2 - Ethyl

CH3CH2O - Ethoxy

(CH3)2CH - Isopropyl

(CH3)2CHO - Isopropoxy

(CH3)3C - Tert-Butyl

(CH3)3CO - Tert-Butoxy

C6H5 - Phenyl

C6H5O - Phenoxy

Ethers can be named by naming two each carbon group as a separate word followed by a space with the word ether. The -OR group can be named as a substituent by using the alkox group name.

Ethers IUPAC Examples

Is CH3-CH2-O-CH3, Called ethyl-methyl-ether or Methoxyethane?

The smaller and shorter alkyl group becomes the alkoxy substituent. The larger and longer alkyl group becomes the alkane base name. Each alkyl group on each oxygen side is separately numbered. The priority of numbering is given to the carbon that is near to the oxygen. The alkoxy side (means, the shorter side) has an "-oxy" ending with its respective alkyl group.

For example, CH3CH2CH2CH2CH2-O-CH2CH2CH3 is of 1-propoxypentane type. If there is trans or cis stereochemistry, still the same rule applies.

FAQ (Frequently Asked Questions)

1. Explain the Uses of Ether?

Ether is the common name for diethyl ether, used as a drug and a solvent. Its anesthetic applications have been abandoned due to its relative toxicity. But, still, it is used for recreational purposes.

Ether is often used as a solvent in organic chemistry. Its toxicity isn't bad at all compared to chloroform or dichloromethane. It evaporates completely and quickly, so it is the solvent of choice in IR spectroscopy.

As a good thing, ether is one of the best solvents to use when doing a Grignard reaction. This is because it's more effective at dissolving magnesium than other aprotic solvents, and protic solvents would react with the reagents.

2. How to Produce Ether?

Ether, in this instance, probably means Diethyl ether, the compound once used as a general anesthetic, rather than the large class of organic compounds. Industrially, diethyl ether is produced by hydrating ethylene vapour (Ethylene) first over catalysts to make ethanol and then dehydrating this as a vapour (Dehydration reaction) over another catalyst to produce the final product.

A typical example is a solvent, and anesthetic diethyl ether commonly referred to simply as "ether" (CH3-CH2-O-CH2-CH3).