CA1095917A

CA1095917A - Method for making organic polycarboxylic acids

Info

Publication number: CA1095917A
Application number: CA287,909A
Authority: CA
Inventors: Ronald L. Markezich; Tohru Takekoshi
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1976-10-04
Filing date: 1977-09-29
Publication date: 1981-02-17
Also published as: SU818478A3; JPS5344558A; FR2391987B1; DE2740357A1; FR2391987A1; GB1567668A; US4128574A

Abstract

ABSTRACT OF THE DISCLOSURE
A method is described for making organic poly-carboxylic acids or anhydrides, such as aromatic ether bis(phtalic acid)s, based on a cyclic imide-cyclic anyhdride exchange reaction at elevated temperatures in the presence of water. In addition to making organic polycarboxylic acid and organic imides there are also generated certain imide carbonyl compounds such as

Description

METHOD FOR MAKIN~ ORGANIC
POLYCARBO m IC ACIDS
The present invention relates to a method or making organic polycarboxyllc acids or anhydrides. More particularly, the present invention relates to an exchange reaction between an organic imide and an organic carboxylic acid or anhydride to make a different or~anic imide and an organic carboxylic acid.
Prior to the present invention, M. Michman et al, J.
Chem. Soc., p. 3856, 1971, Organic Reactions in Melts and Solids, discussed various transacylation reactions involving diacyl-anilines with monobasic or dibasic carboxylic acids, such as phthalic acid. Meyers, U.S. patent 3,956,125, taught that tetra-acids and dianhydrides can be made by initially form-ing a diimide intermediate which can thereafter ~e hydrolyzed to the corresponding tetra-acid ~ollowed by dehydration of the tetra-acid to the corresponding dianhydride. Although Michman et al and Meyers methods can be used in particular situa-tions to make specific carboxylic acids, they are unsuitable in many instances. Michman et al's method, for example, can not be used to make cyclic anhydrides or the corresponding polycar-boxylic acids thereof. Meyers teaches that a diimide intermediate is difficult to hydrolyze if it is N-alkyl substituted instead of N-aryl substituted. The N-alkyl substituted diimide inter-mediate of Meyers can be converted to the dihydrazide which is thereafter oxidized and hydrolyzed to the tetra-acid. If the oxidation is conducted in the presence of an alkali metal hydroxide, the resulting tetra-acid salt must be neutralized to produce the tetra-acid.

~$

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The pre~ent invention i~ based on the di~covery tha~
polycarboxylic acids and anhydrides of the form~la, _ "

(1) (Q~a \ C /
~~. O c can be made by an imide-anhydride exchange reaction, where Q is monovalent or divalent, R is a C(l 30) polyvalent organic radical, D is selected from -O- and -OH, "a" is 0 or 1, "b"
and "c" are respectively 1 or 2, and when "a" is 1 and "c"
is 1, Q is selected from Rl, RlO-, and RlS- and when "a" is 1 "c" is 2,Q is selected from -O-, -S-, -R2-, _oR2O-, -SR2S-and -OR2XR2O-, where Rl and R2 are defined below and X can be O O
-O-, -S-, -C-, -S-, -C-, -CyH2y~ and y is equal to 0 to 5 inclusive.
C~l The above imide-anhydride exchange can be shown as follows:

A + B = B' + A' where A and A' are imides and B and B' are anhydrides. A mix-. ture of a first imide of the formula, ( Z ) ( Q ) ~ R~ NR3 ~

and a first dicarbonyl compound of the formula, . .

t C
is heated in the presence of water at a tem~erature of at least 100C, to produce the polycarboxylic acid of formula (1) and a second imide of the formula, (Ql)~R4 \NR3 C
0 f where R and R4 can be the same or different polyvalent organic radicals as defined more particularly below, R3 is H or C(l 20) monovalent organic radical and Q and Ql can be the same or different monovalent or divalent radicals as defined more particularly below and "d", "e" and "f" have the same values respectively as "a", "b" and "c".
In addition to radicals defined above, Q and Ql of formulas 1 and 3 are the same or different radicals, such as where Rl is C(6 13) aryl radicals,for example, phenyl, tolyl, xylyl, etc; C(l 8) alkyl, for example, methyl, ethyl, propyl J
etc; R2 is selected from arylene radical, such as phenylene, xylylene, tolyleneJ etc. J and C(l 8) alkyleneJ
for example, methylene J dimethylene J trimethylene J etc.; Rl and R as previously defined also include halogenated deriv atives, such as chlorophenyl, bromo~olyl, chlorophenylene J
chloromethyl J bromo butyl J etc. Q and Ql are preferably selected from RD-859~

-~-R2- X -R2-o_ such a~ .

~0~ C~O- , ci,C~cl _o~O~- ~

~ C~o_ J etc.

Radicals included by R and R4, are for example, divalent radicals, such as ~ ' X2~- ~

~C~X' X'~-

2 ~ C ~ X' c2 X2 / ~,~x X~ 1 X' X21 ¦, etc., \C /X' where X' can be hydrogen, chloro, or methyl.

~s~

In addition, R and R4 can be trivalent radicals, auch a8 ~' _~ >

~ , etc.

Radicals included by R3, are for example, H or C(l 8? alkyl,such AS methyl, ethyl, propyl, butyl, etc.; C(6 13) aryl,e.g.,phenyl, etc., and halogenated derivatives thereof, such as chloro-phenyl, bromo-tolyl, etc.
In a preferred procedure, there is provided a method for making aromatic ether phthalic acid of the formula, (5) ~ C-OH
C-OH
O
where R is a C(6 30) aromatic radical and "S" is an integer equal to l or 2, and R5 is monovalent when "g" is 1, and R5, is divalent when "g" is 2, which comprises (1) heating at a temperature of at least 100C, a mi~ture comprising water, phthalic anhydride or phthalic acid and aromatic ether N-organo phthal-imi.de of the formula, (6) R-i ¦ O ~ NR~
C
O g to produce a mixture comprlsing the aromatic ether phthalic acid and an N-organo phthalimide of the formula, \ ~ 6 C
.. .

(2) effecting the separation of the N-organo phthal-imide from the mixture of (1), and

(3) recovering the aromatic ether phthalic acid, where R6 is 1~ or C(l 20)monovalent organo radical and selected from R3 radicals as previously defined.
Radicals included by R5 are,for example, CH3jBr Br CH3 ~r Br CU

C~13Br Br CH3 Br Br ~s~
RD-~590 and divalent organic radicals of the general formula, ~ (X")m~

wherP X" is a member selected from the class consi~ting of divalent radicals of the formulas, -Cy~H2y~~~
O O
.. .-- --C-- , --S-- , -O-, and -S-, where m is 0 or l, y' is a whole number from l to 5.
In a further aspect of the invention, there is pro-vided a method for making aromatic ether phthalic acid of the formula, C-OH
(8) R5- ~ ~
; C OH g where R5 and "g" are as previously defined,which required prior to the present invention, the hydrolysis in the presence of base of an aromatic ether Pl-al1~ylphthalimide of the formula, o (9~ ~ c ]

and R7 is a C(l 8) alkyl radical, resulting in the production of an aromatic ether phthalic acid salt and involving the steps of, ~5~

(A) converting the aromat:ic e~her N-alkyl phthalim~de to the corresponding hydrazide, (B) the oxldation of the hydrazide in the presenc~
of ba~e, and (C) the neutralization of the resulting aromatic ether phthalic acid s~lt, the improvement which comprises, (1) heating the aromatic ether N-alkyl phthal-imide in the presence of water and phthalic anhydride or phthalic acid under sealed conditions to effect the direct exchange between the phthalic anhydride or phthalic acid and the aromatic ether N-alkyl phthal-imide to produce a mixture comprising the aromatic ether phthalic acid and ~-alkyl phthalimide, and (2) effecting the separation of the N-alkyl phthalimide from the mixture of (1), thereby eliminating steps of forming the aromatic ether phthalazide, the oxidation of the hydrazide in the presence of base and the neutralization of the resulting aryl-oxy ether phthalic acid salt.
Included by the polycarboxylic acids and anhydrides of formula (1) which can be made by practicing the method of the present invPntion are,for example, HOOC COOH
HOOC ~ ~ o ~ o ~ COOH

..

HOOC~ ~COOH
I e)~ o ~o ~
HOOC ~COOH

HOO~` COOH
~ O~S~O~
HOOI:~ COOH

HOOC COOH

C ~ ~
HOOC Cl~ Cl COOH

HOOC CH COOH

~ ~} CH~ ~

HOOC COOH
S ~S~S~
HOOC COOH

HOOC COOH
~3s~

HOOC COOH

COOH

COOH

RD-85~0 COOH
CH ~ O
COO~

COO~

COOH

H00C~ "~ ,CH3 COOH
1 J~} ~c~o~
~OOC'~`~' CH3 COOH

HOOC ~ ~ COOH
HOOC ~ ,CH3 ~ COOH
~0~ ,C~O , Some of the preferred imides included by for~ula (2) and methods for making them are shown by Heath et al patent 3,879,428, assigned to the same assignee as ~he present inven-tion. For example, a phthalimide of the formula, O

(10) Y~ NR6 C
o where R6 is as previously defined and Y is a displaceable group selected from nitro, fluoro, chloro, etc., reacted with an alkali diphenoxide of the formula S9~7 RD-85~0 (11) M-o-R7-C)-M
where M is a metal ion of an alkali metal Relected from sodium, potassium, etc., and R7 is selected from -R2XR2-radicals as previously defined. A bisimide i8 formed by a displacement reaction which can be used in accordance with ~he practice of the method of the invention to provide polycar boxylic acids or anhydrides thereof as well as novel N-organo substituted phthalimides as shown by the following equation O O

R7~ 0 ~ \ NR6~ ~ ~ /

,. ..

O O
f c ~ c Among t:he alkall diphenoxides of formula (11) are alkali metal salt:s of the following dihydric phenols:
2,2-bis(2-hydroxyphenyl)propane;
2,4'-di.hydroxydiphenylmethane;
lS bis-(2-hydroxyphenyl)methane;
2,2-bis-(4-hydroxyphenyl)propane;

.

RD-~590 1,1-bis-(4-hydroxyphenyl)ethane;
1,1-bis-(4-hydroxyphenyl)propane;
2,2-bis-(4-hydroxyphenyl)-pentane;
3,3-bis-(4-hydroxyphenyl~pentane;

4,4'-dihydroxybiphenyl;
4,4'-dihydroxy-3,3'~5~5'-tetramethylblphenyl;
2,4'-dihydroxyben~ophenone;
4,4'-dihydroxydiphenylsulfone;
2,4'-dihydroxydiphenylsulfone;
4,4'-dihydroxydiphenyl sulfoxide;
4,4'-dihydroxydiphenyl sulfide;
hydroquinone;
resorcinol;
3,4'-dihydroxydiphenylmethane;
4,4'-dihydroxyben~ophenone; and 4,4'-dihydroxydiphenylether.
The method of the present invention also includes a method for making aryloxy anhydrides, based on the follow ing equation:
O O
ll ll R8O ~ / NR6 + ~ C ~

.. ..
C O

O O

R80~ C\o +[~ \NR6' .. ..
O O

~s~
RD ~590 where R6 is as prevlously de~ined and R8 i8 ~elected ~rom C(6 13) aromatic organic radical~, such as pheny~, ~olyl, xylyl, chlorophenyl, etc.
As previously ind~ cated, the ~bove described exchange reaction between the imide of formula (2), referred to herein-after as the "bisimide" and the di~arbonyl compound of formula (3), referred to hereina~ter as "phthalic anhydride", requires the presence of water in t~e production of the polycarboxylic acid of formula (1), or "tetra-acid" and the imide of formula (4) or "phthalimide". In addition to water, there also can be employed as catalysts, acids such as sulfuric, phosphoric, hydro-chloric, methanesulfonic, fluoroboric, toluenesulfonic, acetic, butyric, trifluoroacetic acids, etc.; metal salts, such as FeC13, ZnC12, SnC14, AlC13 and their bromides, etc.
In the practice of the invention, a mixture of the bisimide and phthalic anhydride is heated in the presence of water or an aqueous catalyst mixture. Preferably, the heating is effected in a closed system, such as an autoclave or reactor to maintain the presence of water. The mixture is heated at a temperature of at least 100C with agitation and thereafter the mixture is allowed to cool to ambient tempreatures. The mixture can then be stripped of volatiles, or bisimide exchange product, such as imide diacid, or tetra-acid, can be recovered by standard techniques. In the event that the reaction mixture is stripped of volatiles at temperatures of up to 200 C under reduced pressure, the resulting residue of the reaction mixture consisting essentially of bisimide exchange product can be mixed further with an additional phthalic anhydride and water and heated in a closed system, as previously described, to effect the further conversion of the bisimide to the .

tetra-acid. Depending upon the ratio of phthalic anhydride to bisimide initially used and the number of reaction cycle3 employed, it has been found that complete conversion of the bisimide to the tetra-acid can be eEfected.
It has been found that a proportion of from 1 mol of phthalic anhydride to up to 20 mols of phthalic anhydride per mol of bisimide will provide for effective re~ults.
Temperatures in the range of from 100~C to 300C, and preferably from 150C to 250C.
The proportion of water can vary from about 0.01 part to 100 parts of water per part of bisimide and preferably from 0.1 part to 10 parts. Metal halide catalysts can be used at from 0.01% to 10~/o~ based on the weight of the bisimide.
The reaction can be conducted in an autoclave, ampoule, or other closed reaction vessel to maintain the presence of water while the mixture is agitated. In certain situations, the reaction can be conducted at atmospheric pressure by bubbling steam into the melt of the mixture. In addition to the tetra-acid, for example the reaction mixture can contain imide-diacids of the formula O O
ll ll R3N ~ ~ R~ Q)a R ~ C ~ (D)b O O
where R, R3, Q, D and a are as previously defined. Some of the imide diacids provided by the method of the present invention are as follows CH N / ~ ~ o ~ CH ~ ~ COOH

S~
R~-8590 o C COO~I
CH3-N ~ O ~ S ~ O ~
C COOH
O O
HOOC ~ ~ N-CH3 ' etc.

HOOC C

- Recovery of the tetra-acid from the mixture can be achieved initially by effecting removal of the phthalimide which can be achieved by solvent extraction, distillation, liquid chromotography, etc. Other teclmiques which can be used are direct extraction of the tetra-acid using an aqueous alkali carbonates or bicarbonates, such as the corresponding - sodium or potassium salts, etc.
The tetra-acids and anhydrides made in accordance with the method of the present invention can be employed to make polyetherimides, as shown by Heath et al, patent 3,875,116.
In addition, the derivatives of diacids made by the present in~ention can be utilized as plasticizers for various organic resins, such as polyvinyl chloride, etc., where there can be utilized from 1 to 50 parts of the anhydride, per 100 parts of organic resin.
In order that those skilled in the art will be better able to practice the invention, the following examples are given by way of illustration and not by way of limitation. All parts are by weight.

~ RD-8590 xample 1. .~.
A mixture of 25.3 parts of 4-phenoxy-~-methylphthal-imide, 29.6 parts of phthalic anhydride and 50 parts of water was heated in an autoclave for 2 hours at 200 DC . The mixture was then allowed to cool to ambient conditions. The resulting mixture was then heated to a temperature of 170 C under atmos-pheric conditions. The residue of the mixture was then dis-tilled under reduced pressure. There was obtained 18.7 parts of a first fraction boiling at 182C at 55 torr. There was also obtained 9.7 parts of a second fraction boiling at 182C
at 50 torr.
The above fractions were combined and heated with about 25 parts of water at reflux for 20 minutes. The mixture was then allowed to cool to room temperature and filtered. The solid was then dispersed in about ~5 parts of methylene chlordie and stirred at reflux or 10 minutes. The mixture was then allowed to cool to room temperature. Upon cooling, a precipi-tate resulted which was filtered. The methylene chloride mother liquor was evaporated to dryness, resulting in the production of 7.39 parts of product. Based on its infrared spectrum, the product was N-methylphthalimide. The crystalline precipitate recovered from the original methylene chloride solution was then washed with additional methylene chloride. There was obtained 18.3 parts of pure phthalic acid.
In addit:ion to the above described two fractions recovered from the original autoclave reaction mixture result-ing in the product:Lon of phthalic acid and N-methylphthalimide, there was also obtained 13.4 parts of a fraction at 257-258C
at 32 torr. In addition to the aforementioned fraction, there ~ 9 RD-8590 was alQo obtained 10.5 parts of a di~tillatlon residue. The aforementioned frRction of 13.4 partl3 was re~luxed wlth about 20 parts of water for 20 minutes. The mixture was allowed to cool and combined with about 25 parts of methylene chloride with stirring. The resulting mixture was filtered,resulting in 9.6 parts of filtration product. BaRed on it8 infrared spectrum, the filtration product was found to be 4-phenoxy-phthalic acid. The methylene chloride mother liquor was evaporated to dryness, resulting in 4 parts of residue. Its infrared spectrum showed it was pure 4-phenoxy-N-methylphthal-imide.
The 10.5 parts distillation residue of the original autoclave mixture was found to be a mixture of 61% by weight of 4-phenoxyphthalic anhydride and 39% by weight of 4-phenoxy-N-methylphthalimide.
The above results show that an exchange occurred between 4-phenoxy-N-methylphthalimide and phthalic anhydride, resulting in a 46% yield of N-methylphthalimide and a 64C/o yield o~;.4-phenoxyphthalic anhydride or acid. This conversion of 4-phenoxy-N-methylphthalimide to 4-phenoxyphthalic anhydride was achieved in a direct manner without any requirement for converting the 4-phenoxy-N-methylphthalimide to the correspond-ing hydrazide or the base hydrolysis thereof, resulting in the prdouction of metal salt requiring the neutralization and heating of the resulting phthalic acid.
Example 2.
A mixture of 2.32 parts of maleic acid, 2.23 parts of N-phenyl phthalimide and 20 parts of water is heated under sealed conditions for 2 hours at 180C. The reaction mixture ~s~
RD-~590 is then allowed to cool to ambient conditions and di~till~d under vacuum. Maleic anhydride is initially recovered followed by phthalic anhydride and N-ph`tnyl maleimide. There i~ obtained a yield of 16% by weight of phthalic anhydrlde and 14.1% by w~ight of N-phenylmaleimide.
Example 3.
A mixture of 20.71 parts of 2,2-bis[4-(N-methyl-phthalimide-4-oxy)phenyl~propane, 125.32 parts of phthalic anhydride and 1.35 part of p-toluene sulfonic acid monohydra~e was heated at 180C for 20 hours under sealed conditions. The mixture was then allowed to cool to atmospheric conditions. It was then distilled at a temperature of 250 and a pressure of 60 mmHg, resulting in the production of a distillate in the form of a mixture of phthalic anhydride and N-methylphthalimide, The residue was then analyzed by high pressure liquid chromato-graphy (HPLC). There was obtained 7% by weight of 2,2-bis[4-(3',4'-dicarboxyphenoxy)-phenyl]propane dianhydride, 40% by weight of 2-[4-~3,4-dicarboxyphenyl)phenyl]-2-[4-(N-methyl-phthalimide-4-oxy)phenyl]propane anhydride and 53% by weight of 2,2-bis[4-(N-methylphthalimide-4-oxy)phenyl]propane.
The above liquid residue was then separated into its component parts by HPLC. The dianhydride was found to have a melting point of 183-187C and the imide anhydride was found to have a melting point of 111-116C. The identity of the imide anhydride having the following formula, ~ C~ ~ C~

was confirmed by its infrared spectra: anhydride carbonyls -1850, 1775 cm 1; imide carbonyl - 1706 cm 1, Calcul~ted for C32H23NO7 by mass spectroscop~: 533.146. Found: 533.148. Tho~e skilled in the art would know that this imide anhydride would be useful as a plasticizer for organic polymers.
Example 4.
In accordance with the procedure of Example 3, a mixture o~ 136 parts of the bisimide, 148 parts of phthalic anhydride and 2.7 parts of water was heatPd or 20 hours at 200C. The mixture was then allowed to cool to atmospheric conditions and distilled at 220C at 60 mm Hg pressure for 15 min-utes. The distillate consisted principally of phthalic anhydride and N-methylphthalimide. The residue was then analyzed by high pressure liquid chromotography. There was obtained 6D/~ by weight of the imide anhydride of Example 3, based on the weight of the bisimide employed in the original mixture.
The above procedure was repeated, except that in addition to the above-mentioned ingredients, 8.2 p rts of trichloroacetic acid was used in the mixture. In addition to trichloroacetic acid, a further mixture was made following ~he same procedure, except that in the place of the 8.2 parts of the trichloroacetic acid and 2.7 parts of water, there was utilized 8.6 parts of para-toluene sulfonic acid and 0.8 part of water. Other mixtures were also heated with added catalyst, except that the water content was significantly increased. The following results were obtained, where BPA-DA
is 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride and BPAIA is the corresponding imide anhydride.

5~Lr~ RD-B590 TABLE I
Catalyst Parts Time Wt X Wt ~/O
Catalyst (partsJ H2 ~hrs) BPA-DA B~A-IA
None --- 2.7 20 0 6 CC13COOH 8.2 2.7 20 3 24 pTSOH 8.6 0.9 20 28 49 -None --- 30.6 1 2 24 None --- 90.0 1 18 50 a - p-toluene sulfonic acid The above results show the effect water and catalyst have on the yield of the BPA-DA and BPA-IA. Unlike Example 3, where water was introduced into the reaction as a mono hydrate of p-toluene sulfonic acid, water was employed directly.
Table I also shows that water can be used free of catalyst, but that a significantly higher amount of water is required in the absence of catalyst to obtain a satisfactory yield of the BPA-DA or the BPA-IA.
Example 5.
The procedure of Example 1 was repeated, except that various catalysts were employed with and without water to deter-mine the effect of such catalyzed mixture on the yield of the 4-phenoxyphthalic anhydride. A mixture of 29 parts of N-methyl-4-(p-methylphenoxy)phthalimide~ and 25 parts of phthalic anhydride were heated under sealed conditions in the presence of 3.6 parts of water which was used either alone or in the presence of another catalyst.
The following results are shown in Table II, where ;~
weight percent of aryloxy anhydride is 4-phenoxyphthalic anhyd-ride, based on the weight of the aryloxy-substituted phthalimide used in the mixture.

~s~

TABLE II
Wt %
Parts Time/Temp Aryloxy Catalyst Cata_yst(hrs) (C) Anhydride pTSOH 3.4 20/180 4 FeC13 3.2 20/180 39 MeSO3Hb 1.9 20/180 53 b - methane sulfonic acid The above results show that when small amounts of water are used in the absence of a catalyst, the yields of aryloxy anhydride is significantly reduced. Another mixture was heated in the absence of water containing 3.2 parts of ferric chloride, resulting in a 4 weight percent of aryloxy anhydride after heating at 180C for 20 hours.
Example 6.
A mixture of 54.6 parts of 2,2-bis[~-(N-methyl phthalimide-4-oxy)phenyl]propane, 148 parts of phthalic anhydride and 200 parts of water is heated with stirring in an autoclave at 210C for 3 hours and then cooled to room temperature. The resulting mixture is distilled under a reduced pressure of approximately 50 Torr. After the initial removal of the water, a mixture of phthalic anhydride and N-methyl phthalimide is collected at 180C-185C-50 Torr, leaving approximately 52 parts of a residue. The residue consists of the starting bisimide, the corresponding monoimide-anhydride and the result-ing dianhydride i.n a ratio of by weight of approximately 5%
bisimide, 32% monoimide-anhydride and 63% dianhydride.
The above procedure is repeated, except that a mixture of 52 parts of the residue, 128 parts of phthalic ~ ~ S~ ~ RD~8590 anhydride and 200 parts of water are employed in the mix-ture.
The reaction mixture is again distilled at 185C-50 Torr to remove volatile fractions. There is obtained 50 parts of residue. It is found to consist of 91 percent by weight of 2,2-bis[4~(3,4-dicarboxyphenoxy)phenyl]propane dianhydride.
The crude product is recrystallized from 400 parts of toluene and a yield of 39 parts of the dianhydride is obtained having a melting point of 185C-187C.
Although the above examples are limited to only a few of the very many variables, such as reactants, catalysts, con-ditions, etc., which can be used in the practice of the method of the present invention, it should be understood that the method of the present invention is directed to the production of the polycarboxylic acids and anhydrides of formula (1), based on an interchange between imides of formula (2) and dicarbonyl compounds of formula (3). As shown by United States patent 4,116,9S0 issued September 26, 1978 to Jimmy L. Webb and assigned to the same assignee as the present invention, recovery of the imide of formula (4) can be effected by venting the reaction mixture under equilibrium conditions.

. ~ ., .
,,

Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A method which comprises, (1) heating at a temperature of at least 100°C. in the presence of water, a mixture comprising a first organic imide of the formula, , and a first organic anhydride, or polycarboxylic acid precursor thereof of the formula, , for a time sufficient to effect an imide-anhydride exchange to produce a mixture comprising a second organic imide of the formula, , and a second polycarboxylic acid or anhydride thereof of the formula, Claims 1 continued:

, (2) effecting the separation of the second organic imide or second polycarboxylic acid or anhydride from the mixture of (1), where Q and Q1 are the same or different monovalent radicals selected from R1-, R10-, R1S-, the same or different divalent radicals selected from -O-, -S-, -R2-, -O-R2-O-, -S-R2-S- and -OR2XR2O-, and Q and Q1 can have different valences, X is selected from -O-, -S-, , , and , and y is equal to 0 to 5 inclusive, R and R4 are selected from the same or different polyvalent organic radicals, R1 is selected from C(6-13) monovalent aromatic radicals, and C(1-8) alkyl radicals, R2 is selected from C(6-13) divalent aromatic organic radicals and C(1-8) alkylene radicals, R3 is selected from H and C(1-20) monovalent organic radicals, D is selected from -O-and -OH, "a" is a whole number equal to 0 or 1, "b" is an integer equal to 1 or 2 and "c" is an integer equal to 1 or 2, when "a" and "c" are respectively 1, Q is a monovalent radical, and when "a" is 1 and "c" is 2, Q is a divalent radical, and "a", "b" and "c" and "d", "e" and "f" have the same values respectively.

2. A method in accordance with claim 1, for making an organic imide.

3. A method in accordance with claim 1, where the first organic imide is an organic bisimide.

4. A method in accordance with claim 1, where the imide anhydride exchange results in the production of an imide dicarboxylic acid.

5. A method which comprises:
(1) heating at a temperature of at least 100°C. in the presence of water, a mixture comprising a bisimide of the formula, , and phthalic anhydride or phthalic acid to produce a mixture comprising , and an N-organo phthalimide of the formula, , (2) effecting the separation of the N-organo phthal-imide from the mixture of (1), where Q is a divalent radical selected from -O-, -S-, -R2-, -O-R2-O-, -S-R2-S- and -OR2XR2O-, X is selected from -O-, -S-, , , and , and y is equal to 0 to 5 inclusive, R2 is selected from C(6-13) divalent aromatic organic radicals and C(1-8) alkylene radicals, and R3 is selected from H and C(1-20) monovalent organic radicals.

6. A method in accordance with claim 5, where separation of the resulting N-organophthalimide is achieved by distillation.

7. A method in accordance with claim 5, where Q is and R is methyl.

8. A method in accordance with claim 5, where the mixture is heated in the presence of a ferric chloride catalyst.

9. A method in accordance with claim 5, where the mixture is heated under sealed conditions.

10. A method in accordance with claim 5, where the mixture is distilled after the mixture has been restored to ambient conditions to effect the separation of N-organo-phthalimide from a reaction mixture comprising anhydride and .

11. A method in accordance with claim 5, where the separation of the N-alkyl phthalimide is achieved by solvent extraction.

12. An imide carbonyl compound having the formula, where R is a trivalent aromatic organic radical selected from the class consisting of R3 is a C(1-20) organic radical selected from the class consisting of C(1-8) alkyl radicals, C(6-13) aryl radicals, and halogenated derivatives thereof, R2 is selected from arylene radicals and C(1-8) alkylene radicals and halogenated derivatives thereof, D is selected from the class consisting of -O- and -OH, X is a member of the class consisting of -O-, -S-, , and , and b is an integer equal to 1 or 2, and when b is 1, D is -O- and when b is 2, D is -OH.

13. The compound in accordance with claim 12, having the formula .

14. The compound in accordance with claim 12, having the formula, .

15. The compound in accordance with claim 12, having the formula .

16. The compound in accordance with claim 12, having the formula .