Method for the preparation of bis(haloimides)
Bis(halophthalimides) are prepared in a solvent such as ortho-dichlorobenzene or anisole, by a reaction at a temperature of at least 150° C. between at least one diamine compound and at least one halophthalic anhydride in the presence of imidization catalyst. The reaction produces a vapor stream comprising solvent and water formed as a by-product of the imidization reaction. A suitable vapor handling system comprising a partial reflux condenser is used to recycle the solvent, maintain the reactant concentration, conduct the reaction at a higher temperature, and effect more efficient conversion of reactants to product bis(halophthalimides). Reaction conditions disclosed may also be used to prepare organic polyimides.
1 . A method for preparing a bis(halophthalimide), said method comprising steps (a)-(d):
(a) contacting in a substantially water-immiscible solvent at least one halophthalic anhydride with at least one diamine to form a reaction mixture;
(b) heating the reaction mixture to form a product mixture comprising the substantially water-immiscible solvent and a product bis(halophthalimide), and a vapor stream comprising the substantially water immiscible solvent and water;
(c) introducing the vapor stream into a vapor handling system comprising a partial reflux condenser; and
(d) separating the vapor stream to provide a water-rich component and a solvent-rich component.
2 . The method of claim 1 wherein said bis(halophthalimide) has structuture I
wherein X 1 is independently in each instance, a fluorine, chlorine, bromine or iodine group; R 1 is a hydrogen, C 1 -C 20 aliphatic radical, a C 2 -C 20 aromatic radical, or a C 4 -C 20 cycloaliphatic radical; Q is a C 2 -C 20 divalent aliphatic radical, a C 2 -C 40 divalent aromatic radical, or a C 4 -C 20 divalent cycloaliphatic radical; “a” is independently at each occurrence an integer in a range from 1 to 4; and “b” is independently at each occurrence an integer from 0 to 3.
3 . The method of claim 1 wherein said halophthalic anhydride is 4-chlorophthalic anhydride, 3-chlorophthalic anhydride, 4-fluorophthalic anhydride, 3-fluorophthalic anhydride, 4,5-dichlorophthalic anhydride, 3,6-dichlorophthalic anhydride, or a mixture comprising at least two of the foregoing.
4 . The method of claim 1 wherein the at least one diamine has structure II
H 2 N-Q-NH 2 II
wherein Q is a C 2 -C 20 divalent aliphatic radical, a C 2 -C 40 divalent aromatic radical, or a C 4 -C 20 divalent cycloaliphatic radical.
5 . The method of claim 1 wherein the at least one diamine is selected from the group consisting of 4,4′-oxydianiline, and bis(4-aminophenyl)sulfone.
6 . The method of claim 1 wherein said diamine is selected from the group consisting of aromatic diamines III and diamines IV
wherein R 2 and R 3 are independently at each occurrence a halogen atom, a nitro group, a cyano group, a C 1 -C 20 aliphatic radical, a C 2 -C 40 aromatic radical, or a C 4 -C 20 cycloaliphatic radical; and “n” and “m” are independently integers in a range from 0 to 4.
7 . The method of claim 6 wherein the aromatic diamine is selected from the group consisting of meta-phenylene diamine and para-phenylene diamine.
8 . The method of claim 1 wherein the solvent has a boiling point at atmospheric pressure of at least 110° C.
9 . The method of claim 1 wherein the solvent is selected from the group consisting of chlorobenzene, ortho-dichlorobenzene, anisole, toluene, ortho-xylene, meta-xylene, para-xylene, mesitylene, phenetole, veratrole, and mixtures of the foregoing solvents.
10 . The method of claim 1 wherein step (b) comprises heating the reaction mixture to at least about 150° C.
11 . The method of claim 1 wherein the reaction mixture further comprises an imidization catalyst.
12 . The method of claim 11 wherein the imidization catalyst comprises sodium phenylphosphinate.
13 . The method of claim 1 wherein the halophthalic anhydride, and the diamine when taken together are present in an amount corresponding to an initial solids content of the reaction mixture in a range from about 5% to about 25% by weight.
14 . The method of claim 1 wherein said contacting is carried out in a reaction vessel, and wherein the solvent-rich component is refluxed back into the reaction vessel.
15 . A method for preparing a bis(chlorophthalimide), said method comprising steps (a)-(d):
(a) contacting in a substantially water-immiscible solvent a mixture comprising at least one chlorophthalic anhydride and at least one diamine to form a reaction mixture;
(b) heating the reaction mixture to form a product mixture comprising said solvent and at least one product bis(chlorophthalimide), and a vapor stream comprising the substantially water-immiscible solvent and water;
(c) introducing the vapor stream into a vapor handling system comprising a partial reflux condenser; and
(d) separating the vapor stream to provide a water-rich component and a solvent-rich component.
16 . The method of claim 15 wherein the solvent-rich component is refluxed back into the reactor.
17 . A method for preparing a bis(chlorophthalimide), said method comprising steps (a)-(d):
(a) contacting in a solvent comprising ortho-dichlorobenzene a mixture comprising at least one chlorophthalic anhydride, meta-phenylene diamine, and para-phenylene diamine to form a reaction mixture;
(b) heating the reaction mixture to form a product mixture comprising said solvent and product bis(chlorophthalimide) and a vapor stream comprising ortho-dichlorobenzene and water;
(c) introducing the vapor stream into a vapor handling system comprising a partial reflux condenser; and
(d) separating the vapor stream to provide a water-rich component and an ortho-dichlorobenzene-rich component.
18 . The method of claim 17 wherein the solvent-rich component is refluxed back into the reactor.
19 . A method for preparing an organic polyimide, said method comprising steps (a)-(d):
(a) contacting in a substantially water-immiscible solvent a mixture comprising at least one dianhydride and at least one diamine to form a reaction mixture;
(b) heating the reaction mixture to form a product mixture comprising the substantially water-immiscible solvent and a product organic polyimide, and a vapor stream comprising the substantially water-immiscible solvent and water;
(c) introducing the vapor stream into a vapor handling system comprising a partial reflux condenser; and
(d) separating the vapor stream to provide a water-rich component and a solvent-rich component.
20 . The method of claim 19 wherein the solvent comprises ortho-dichlorobenzene.
21 . The method of claim 19 wherein the mixture further comprises an imidization catalyst.
22 . The method of claim 21 wherein the imidization catalyst comprises sodium phenyl phosphinate.