US 12,378,356 B2
Method for purifying branched polyethylene glycol
Midori Hirai, Kawasaki (JP); and Kyu Takeuchi, Kawasaki (JP)
Assigned to NOF CORPORATION, Tokyo (JP)
Appl. No. 17/788,841
Filed by NOF CORPORATION, Tokyo (JP)
PCT Filed Dec. 21, 2020, PCT No. PCT/JP2020/047603
§ 371(c)(1), (2) Date Jun. 24, 2022,
PCT Pub. No. WO2021/132123, PCT Pub. Date Jul. 1, 2021.
Claims priority of application No. 2019-237989 (JP), filed on Dec. 27, 2019.
Prior Publication US 2022/0363824 A1, Nov. 17, 2022
Int. Cl. C08G 65/30 (2006.01)
CPC C08G 65/30 (2013.01) 1 Claim
 
1. A method for producing and treating a branched polyethylene glycol containing an impurity having a vinyl ether group, the method comprising:
reacting a compound represented by the following formula [2] with ethylene oxide in the presence of an alkaline catalyst to achieve polymerization and thereby produce a branched polyethylene glycol compound which (a) is represented by the following formula [1] and has a weight average molecular weight of 40,000 or more, and (b) contains an impurity having a vinyl ether group:

OG Complex Work Unit Chemistry
wherein in the formula [1] and the formula [2],
Z is a residue obtained by removing, from a compound having 3 to 5 active hydrogen groups, the active hydrogen groups;
Y1 and Y2 each independently represent an alkylene group having 1 to 12 carbon atoms;
A represents a protecting group for an active group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group;
Polymer represents a polyethylene glycol chain;
1 is 0 or 1;
m is 0 or 1; and
a and b are integers satisfying 1≤a≤3, 2≤b≤4, and 3≤a+b≤5,
adding to the branched polyethylene glycol compound at least one solid acid selected from the group consisting of magnesium silicate, aluminum silicate, and aluminum magnesium silicate and having a specific surface area of 50 to 250 m2/g in the presence of an aprotic organic solvent to obtain a mixture;
stirring the mixture; and
subsequently separating the solid acid,
wherein the vinyl ether group of the impurity contained in the branched polyethylene glycol compound is converted into a hydroxyl group by treatment with the solid acid, and
wherein the impurity is represented by following formula (ii):

OG Complex Work Unit Chemistry
in the formula (ii),
Z, Y1, Y2, A, Polymer, l, m, and a are the same as defined above and 0≤c≤3, 1≤d≤4 and 3≤a+c+d≤5 are satisfied.