Ether

In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula R−O−R′, where R and R′ represent the organyl groups. Ethers can again be classified into two varieties: if the organyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (CH3−CH2−O−CH2−CH3). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

Tables

Aliphatic polyethers · Nomenclature › Polyethers

Paraformaldehyde

Name of the polymers with low to medium molar mass

Paraformaldehyde

Name of the polymers with high molar mass

Polyoxymethylene (POM) or polyacetal or polyformaldehyde

Preparation

Step-growth polymerisation of formaldehyde

Repeating unit

–CH2O–

Examples of trade names

Delrin from DuPont

Polyethylene glycol (PEG)

Name of the polymers with low to medium molar mass

Polyethylene glycol (PEG)

Name of the polymers with high molar mass

Polyethylene oxide (PEO) or polyoxyethylene (POE)

Preparation

Ring-opening polymerization of ethylene oxide

Repeating unit

–CH2CH2O–

Examples of trade names

Carbowax from Dow

Polypropylene glycol (PPG)

Name of the polymers with low to medium molar mass

Polypropylene glycol (PPG)

Name of the polymers with high molar mass

Polypropylene oxide (PPOX) or polyoxypropylene (POP)

Preparation

anionic ring-opening polymerization of propylene oxide

Repeating unit

–CH2CH(CH3)O–

Examples of trade names

Arcol from Covestro

Polytetramethylene glycol (PTMG) or Polytetramethylene ether glycol (PTMEG)

Name of the polymers with low to medium molar mass

Polytetramethylene glycol (PTMG) or Polytetramethylene ether glycol (PTMEG)

Name of the polymers with high molar mass

Polytetrahydrofuran (PTHF)

Preparation

Acid-catalyzed ring-opening polymerization of tetrahydrofuran

Repeating unit

−CH2CH2CH2CH2O−

Examples of trade names

Terathane from Invista and PolyTHF from BASF

Name of the polymers with low to medium molar mass	Name of the polymers with high molar mass	Preparation	Repeating unit	Examples of trade names
Paraformaldehyde	Polyoxymethylene (POM) or polyacetal or polyformaldehyde	Step-growth polymerisation of formaldehyde	–CH2O–	Delrin from DuPont
Polyethylene glycol (PEG)	Polyethylene oxide (PEO) or polyoxyethylene (POE)	Ring-opening polymerization of ethylene oxide	–CH2CH2O–	Carbowax from Dow
Polypropylene glycol (PPG)	Polypropylene oxide (PPOX) or polyoxypropylene (POP)	anionic ring-opening polymerization of propylene oxide	–CH2CH(CH3)O–	Arcol from Covestro
Polytetramethylene glycol (PTMG) or Polytetramethylene ether glycol (PTMEG)	Polytetrahydrofuran (PTHF)	Acid-catalyzed ring-opening polymerization of tetrahydrofuran	−CH2CH2CH2CH2O−	Terathane from Invista and PolyTHF from BASF

· Physical properties

Ether