Production method of polycarbonate
View Patent ↗A method for producing a polycarbonate, comprises: continuously feeding a dihydroxy compound having a portion represented by —(—CH 2 —O—)— in a part of a structure thereof and a carbonic acid diester; and continuously performing polycondensation to produce a polycarbonate, wherein the method satisfies all of the conditions: (A) at least two reactor vessels connected in series are used; (B) a reaction solution reacted in a first reactor of the first vessel is continuously fed to a reactor of the second vessel; (C) the first reactor is equipped with a reflux condenser; and (D) a reflux ratio in the first reactor is from 0.01 to 10 based on a distillate volume.
1. A method for producing a polycarbonate, comprising:
continuously feeding a dihydroxy compound containing a dihydroxy compound having a portion represented by the following formula (1) in a part of a structure thereof and a carbonic acid diester; and
continuously performing polycondensation to produce a polycarbonate,
wherein all of the following conditions (A) to (D) are satisfied:
(A) at least two reactor vessels connected in series are used,
(B) a reaction solution reacted in a first reactor of the first vessel is continuously fed to a second reactor of the second vessel,
(C) the first reactor is equipped with a reflux condenser, and
(D) a reflux ratio in the first reactor is from 0.01 to 10 based on a distillate volume:
provided that a case where the portion represented by formula (1) is a portion constituting a part of —CH 2 —OH is excluded.
2. The production method of a polycarbonate according to claim 1 ,
wherein an internal temperature of the first reactor is from 150 to 250° C. and a variation of the internal temperature is within 10° C.
3. The production method of a polycarbonate according to claim 1 ,
wherein an internal pressure of the first reactor is from 5 to 80 kPa and a variation of the internal pressure is within 5 kPa.
4. The production method of a polycarbonate according to claim 1 ,
wherein a temperature of a heating medium of the first reactor is 265° C. or less and a temperature difference from an internal temperature of the first reactor is from 5 to 80° C.
5. The production method of a polycarbonate according to claim 1 ,
wherein the second reactor is equipped with a reflux condenser.
6. The production method of a polycarbonate according to claim 1 ,
wherein an internal volume of the first reactor is 20 L or more.
7. The production method of a polycarbonate according to claim 1 ,
wherein a distillate volume of a monohydroxy compound generated as a by-product by a transesterification reaction in the first reactor is from 30 to 90% of a theoretical amount.
8. The production method of a polycarbonate according to claim 1 ,
wherein a content of a monohydroxy compound in the reaction solution at an outlet of the first reactor is 20 wt % or less.
9. The production method of a polycarbonate according to claim 1 ,
wherein out of the dihydroxy compounds, a boiling point at 5 kPa of at least one dihydroxy compound is 250° C. or less.
10. The production method of a polycarbonate according to claim 1 ,
wherein an average molecular weight of the dihydroxy compound used for reaction is 220 or less.
11. The production method of a polycarbonate according to claim 1 ,
wherein the dihydroxy compound having the portion represented by formula (1) is a compound having a cyclic ether structure.
12. The production method of a polycarbonate according to claim 1 ,
wherein the dihydroxy compound having the portion represented by formula (1) is a compound represented by the following formula (2):
13. The production method of a polycarbonate according to claim 1 , comprising:
a step of distilling and purifying a monohydroxy compound from liquid distillates coming out of all reactors and recovering the monohydroxy compound.
14. The production method of a polycarbonate according to claim 7 ,
wherein the monohydroxy compound is phenol.