Separation method
To provide a method capable of separating a monofunctional species, bifunctional species, etc. of a fluorinated ether compound having a polyfluoropolyether chain and a predetermined functional group in good yield and with high separation performance. A separation method for separating a compound represented by the formula (1) and a compound represented by the formula (2) from a mixture containing them by chromatography using a stationary phase and a mobile phase, wherein the mobile phase contains at least one type of specific solvent selected from a hydrofluoroolefin, a hydrochlorofluoroolefin, a chlorofluoroolefin, a cyclic hydrofluoroolefin, a cyclic hydrochlorofluoroolefin, a cyclic chlorofluoroolefin, a cyclic hydrofluorocarbon, a cyclic hydrochlorofluorocarbon, a cyclic chlorofluorocarbon and a perfluoroketone: A-(OX) m —O—Z—(R) n1 Formula (1) (R) n2 —Z—(OX) m —O—Z—(R) n3 Formula (2)
1 . A separation method for separating a compound represented by the following formula (1) and a compound represented by the following formula (2) from a mixture containing them by chromatography using a mobile phase and a stationary phase, which comprises
a step of supplying the mixture to the stationary phase of the chromatography to let it be adsorbed on the stationary phase, and
a step of supplying, to the stationary phase having the mixture adsorbed thereon, a mobile phase containing at least one type of specific solvent selected from the group consisting of a hydrofluoroolefin, a hydrochlorofluoroolefin, a chlorofluoroolefin, a cyclic hydrofluoroolefin, a cyclic hydrochlorofluoroolefin, a cyclic chlorofluoroolefin, a cyclic hydrofluorocarbon, a cyclic chlorofluorocarbon and a perfluoroketone:
A-(OX) m —O—Z—(R) n1 Formula (1)
(R) n2 —Z—(OX) m —O—Z—(R) n3 Formula (2)
where
A is an alkyl group or a fluoroalkyl group,
X is an alkylene group or a fluoroalkylene group having one or more fluorine atoms,
m is an integer of 2 or more,
Z is a (n1+1)-valent, (n2+1)-valent or (n3+1)-valent linking group,
R is any functional group selected from the group consisting of —OH, —CR 1 ═CR 2 R 3 (where R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R 2 and R 3 are each independently a hydrogen atom or a fluorine atom), —CH 3 , —NH 2 , —SH, -Ph, —F, —Cl, —Br, —I, —C≡CH and —N 3 ,
n1 is an integer of 1 or more,
n2 is an integer of 1 or more, and
n3 is an integer of 1 or more.
2 . The separation method according to claim 1 , wherein in the above formulas (1) and (2), A is a fluoroalkyl group, and X is a fluoroalkylene group having one or more fluorine atoms.
3 . The separation method according to claim 1 , wherein in the above formulas (1) and (2), n1, n2 and n3 are the same integers.
4 . The separation method according to claim 1 , wherein the mixture further contains a compound represented by the following formula (3), and it is separated into the compound represented by the formula (1), the compound represented by the formula (2), and the compound represented by the formula (3):
A-(OX) m —O-A Formula (3)
where A, X, and m are the same as those in the above formulas (1) and (2).
5 . The separation method according to claim 1 , wherein the specific solvent is a solvent that does not contain chlorine atoms.
6 . The separation method according to claim 1 , wherein the specific solvent includes at least one type selected from the group consisting of a hydrofluoroolefin, a cyclic hydrofluoroolefin and a cyclic hydrofluorocarbon.
7 . The separation method according to claim 1 , wherein in the above formulas (1), (2) and (3), (OX) m contains the following structure:
{(OCF 2 ) m21 ·(OCF 2 CF 2 ) m22 }
where m21 is an integer of 1 or more, m22 is an integer of 1 or more, and m21+m22 is an integer of from 2 to 500.
8 . The separation method according to claim 1 , wherein the stationary phase is selected from the group consisting of aluminum oxide, silica gel, magnesium oxide, aluminum silicate, magnesium silicate, chemically modified silica gel and diatomaceous earth.
9 . The separation method according to claim 1 , wherein the chromatography is column chromatography.