Polyetherimide of improved color and process of preparing

1. A method for the manufacture of a polyetherimide composition, the method comprising:

contacting a bis(phthalimide) having the formula

with an alkali metal salt of a dihydroxy aromatic compound having the formula

MO—Z—OM,

in an oil-jacketed reactor, in the presence of a catalyst and 0 to 10% of a capping agent, and at an oil temperature of 150° C. to 320° C., or 180° C. to 240° C., or 188° C. to 192° C., to form a polyetherimide comprising structural units having the formula

wherein in the foregoing formulae

X is fluoro, chloro, bromo, iodo, nitro, or a combination comprising at least one of the foregoing;

R is an aromatic hydrocarbon group having 6 to 27 carbon atoms, a halogenated derivative thereof, a straight or branched chain alkylene group having 2 to 10 carbon atoms, a halogenated derivative thereof, a cycloalkylene group having 3 to 20 carbon atoms, a halogenated derivative thereof, —(C 6 H 10 ) z — wherein z is an integer from 1 to 4, an aromatic hydrocarbyl moiety having from 1 to 6 aromatic groups, and a divalent group of the formula

wherein Q 1 is —O—, —S—, —C(O)—, —SO 2 —, —SO—, —C y H 2y — wherein y is an integer from 1 to 5, or a combination thereof;

M is an alkali metal;

Z is an aromatic C 6-24 monocyclic or polycyclic moiety optionally substituted with 1 to 6 C 1-8 alkyl groups, 1 to 8 halogen atoms, or a combination thereof; and

n is an integer greater than 1; and

wherein the polyetherimide has a Yellowness Index of from less than 93 to 50.

2. The method of claim 1 , wherein the reactor is mixed using an agitator with two sets of pitched turbine blades, with a blade to vessel diameter ratio range of about 0.45 to 0.65, at a speed in a range from about 40 to about 90 revolutions per minute, in a reactor with a volume range from about 20 to 35 cubic meters, and a cylindrical height to diameter ratio range of about 1.3 to about 1.6.

3. The method of claim 2 , wherein the agitator has two sets of 45° pitched turbine blades with a blade to vessel diameter ratio of about 0.54 at a speed in a range from about 70 to about 86 revolutions per minute in a reactor with volume of about 28 cubic meters with a cylindrical height to diameter ratio of about 1.45.

4. The method of claim 1 , further comprising quenching the polymerization with an acid at a temperature of from 130° C. to 200° C., or from 145° C. to 155° C.

5. The method of claim 4 , wherein the acid is phosphoric acid.

6. The method of claim 1 , wherein

X is chloro;

each R is independently a divalent group of formulas

wherein Q′ is —O—, —S—, —C(O)—, —SO 2 —, —SO—, —C y H 2y — wherein y is an integer from 1 to 5 or a halogenated derivative thereof (which includes perfluoroalkylene groups), or —(C 6 H 10 ) z —

wherein z is an integer from 1 to 4;

Z is a group of the formula

wherein

R a and R b are each independently the same or different, and are a halogen atom or a monovalent C 1-6 alkyl group;

p and q are each independently integers of 0 to 4;

c is 0 to 4;

X a is a single bond, —O—, —S—, —S(O)—, —S(O) 2 —, —C(O)—, or a C 1-18 organic bridging group; and

n is 5 to 500.

7. The method of claim 6 , wherein

R is m-phenylene, p-phenylene, bis(4,4′-phenylene)sulfone, bis(3,4′-phenylene)sulfone, bis(3,3′-phenylene)sulfone, or a combination comprising at least one of the foregoing; and

Z is a divalent group of the formula

wherein Q is —O—, —S—, —C(O)—, —SO 2 —, —SO—, or —C y H 2y — wherein y is an integer from 1 to 5 or a halogenated derivative thereof.

8. The method of claim 7 , wherein Q is 2,2-isopropylidene.

9. The method of claim 1 , further comprising up to 15 mole % of a capping agent.

10. The method of claim 9 , wherein the capping agent is of the formula

M 2 -O—Z 2

wherein

M 2 is an alkali metal and

Z 2 is derived from a monohydroxy aromatic compound of the formula

wherein

R c and R d are each independently a halogen atom or a monovalent C 1-6 alkyl group;

r and s are each independently integers of 0 to 4;

c is zero to 4;

t is 0 or 1, provided that when t is zero, X b is hydrogen or a C 1-18 alkyl group, and when t is 1, X b is a single bond, —O—, —S—, —S(O)—, —S(O) 2 —, —C(O)—, or a C 1-18 organic bridging group.

11. The method of claim 10 , wherein Z 2 is of the formula

or a combination comprising at least one of the foregoing.

12. The method of claim 1 , wherein

the contacting the bis(phthalimide) is at an oil temperature of 150° C. to 320° C., in the presence of a catalyst and up to 15 mole % of a capping agent, based on the total moles of the alkali salt the dihydroxy aromatic compound and the capping agent;

the reactor contents are mixed using an agitator with two sets of pitched turbine blades, with a blade to vessel diameter ratio range of about 0.45 to 0.65, at a speed in a range from about 40 to about 90 revolutions per minute, in a reactor with a volume range from about 20 to 35 cubic meters, and a cylindrical height to diameter ratio range of about 1.3 to about 1.6;

the method further comprises quenching the polymerization with an acid at a temperature of from 130° C. to 200° C.; and

the polyetherimide has a Yellowness Index of from less than 93 to 50r.

13. The method of claim 12 , wherein the agitator has two sets of 45° pitched turbine blades with a blade to vessel diameter ratio of about 0.54 at a speed in a range from about 70 to about 86 revolutions per minute in a reactor with volume of about 28 cubic meters with a cylindrical height to diameter ratio of about 1.45.

14. The method of claim 12 , wherein the polyetherimide has a Yellowness Index of from less than 70 to 50.

15. The method of claim 12 , wherein the polyetherimide has a Yellowness Index of from less than 80 to 50.

16. The method of claim 12 , wherein

R is m-phenylene, p-phenylene, bis(4,4′-phenylene)sulfone, bis(3,4′-phenylene)sulfone, bis(3,3′-phenylene)sulfone, or a combination comprising at least one of the foregoing; and

Z is a divalent group of the formula

wherein Q is —O—, —S—, —C(O)—, —SO 2 —, —SO—, or —C y H 2y — wherein y is an integer from 1 to 5 or a halogenated derivative thereof.

17. The method of claim 16 , wherein Q is 2,2-isopropylidene.

18. The method of claim 1 , wherein the polyetherimide has a Yellowness Index of from less than 80 to 50.

19. The method of claim 1 , wherein the polyetherimide has a Yellowness Index of from less than 70 to 50.