CA1144554A - Method for making aromatic ether imides - Google Patents

Abstract

Abstract of the Disclosure A method for making aromatic ether imides is provided by effecting the displacement of reactive radicals on a phthal-imide nucleus with a mono- or bis-alkali metal phenoxide in the presence of a nonpolar solvent and a phase transfer cat-alyst, such as a tetra-ammonia salt. The aromatic ether imides made by the present invention are useful intermediates for making aromatic ether anhydrides and aromatic bis(ether anhy-drides).

Description

~ 4S54 RD 10770 The present invention relates to a method for making aromatic ether imides by effecting the condensation of a phenoxide salt with a nuclear-substituted phthalimide in the presence of a nonpolar solvent and a phase transfer catalyst. More particularly, the present invention relates to a method for making an aromatic ether phthalimide or an aromatic bis (ether phthalimide).
Prior to the present invention, methods involving the condensation of an alkali metal phenoxide with a nuclear substituted phthalimide as shown by Heath et al United States Patents 3,879,428 i~sued April 22, 1975; 3,957,862 issued May 18, 1976 and 3,956,320 issued May 11, 1976 and assigned to the same assignee as the present invention, or Meyers United States Patent 3,965,125 issued June 22, 1976, were generally based on the use of a dipolar aprotic solvent to facilitate reaction.
Those skilled in the art know that it is often economically unattractive to effect the synthesis of various organic materials using dipolar aprotic solvents because such solvents are expensive and often subject to a variety of chemical side reactions which render them useless for recycling.

"` 11~554 RD-10770 The present invention is based on the discovery that aromatic ether imides of the formula, ( 1 ) Rl ~

can be made without the use of a dipolar aprotic solvent, by effecting the reaction between the alkali metal phenoxide salt or diphenoxide salt and the nuclear substituted phthal-imide in a nonpolar organic solvent and in the presence of a phase transfer catalyst, where R is a monovalent radical selected from hydrogen, a C(1 8) alkyl radical and C(6 13) aryl radical, Rl is a C(6 30) aromatic organic radical, and a is an integer equal to 1 or 2, and when a is 1, Rl is mono-valent and when a is 2, R1 is divalent.
Statement of the Invention There is provided by the present invention, a method for making ar~matic ether imides of formula (1), which com-prises (A) heating a substituted phthalimide of the formula, o

(2) Xl ~ NR

and an alkali metal phenoxide salt of the formula,

(3) Rl --~OM)a in the presence of a nonpolar organic solvent :''`~ ' and an effective amount of a phase transfer catalyst of the formula,

(4) (R )4QY "
(B) agitating the resulting mixture with a pre-cipitating or extractive organic solvent for the resulting bisimide or allowing the mixture to cool and (C) recovering the bisimide from the mixture of (B), where R, Rl and a is as previously defined, M is an alkali metal ion, R is a C(l 16) alkyl radical and C(6 13) aromatic radical, Q is a group Va element selected from N and P, Y is a halogen or carbethoxy radical and Xlis a radical selected from nitro and halo.
Radicals included by R, are for example, phenyl, tolyl, xylyl, naphthyl, chlorophenyl, bromonaphthyl, etc., and alkyl radicals such as methyl, ethyl, propyl, etc. Radicals included by Rl are the aforementioned monovalent aromatic radicals included by R, divalent aromatic radicals, such as phenylene, tolyene, naphthylene, and Rl more particularly includes ~ ' ~ ~

1~44~5'~

C ~ r Br CH3 Br Br , and ~ (CH3)2 CH3Br Br CH3 Br Br and divalent organic radicals of the general formula, ~ (X)m~

where X i8 a member selected from the class consisting of S divalent radicals of the formula, O O
... ..
-CyH2y , ~C~ , ~S~

-O-, and -S-, where m is 0 or 1, y is a whole number from 1 to 5.
Radicals included by R2 are, for example, propyl, butyl, pentyl, hexyl, heptyl, octyl and phenyl. M is more particularly sodium, potassium, lithium, rubidium, etc; Y is more particularly, chloro, bromo, iodo, acetato, etc.
Included by the substituted phthalimides of formula (2), are for example, 4-nitro,N-phenylphthalimide; 3-nitro,N-lS phenylphthalimide; 4-nitro,N-methylphthalimide; 3-nitro,N-methylphthalimide; 4-fluoro,N-methylphthalimide; 3-fluoro,N-methylphthalimide; 4-chloro,N-methylphthalimide; 3-chloro,N-methylphthalimide, etc. These substituted phthalimides can be made by standard procedures, such as effecting reaction between substantially equal mols of the corresponding phthalic anhy-dride and an organic amine in the presence of refluxing acetic acid. Included by the organic amines which can be used, are, ~1~4554 RD 10770 for example, aniline, toluidene, etc., methylamine, ethyl-amine, etc. Included by the pase transfer catalysts of for-mula (4) are, for example, tetrabutylammonium bromide, tetra-propylammonium bromide, tetrabutylammonium chloride, tetra-butylammonium fluoride, tetrabutylammonium acetate, tetra-hexylammonium chloride, tetraheptylammonium chloride, Aliquat 336 phase transfer catalyst (methyltrioctylammonium chloride, manufactured by the General Mills Company), tetrabutylphos-phonium bromide, tetraphenylphosphonium bromide, tetraphenyl-ammonium bromide, tetrabutylphosphonium chloride, etc.
The alkali metal salts of formula (3) can be made by various procedures, including the flash evaporation of bisphenoxide alkali metal salt hydrate or an aqueous slurry tereof, as shown by the Tohru Takakoshi United States Patent 4,202,993 issued May 13, 1980, or by azeotroping water from an aqueous mixture of bisphenoxide alkali metal salt and toluene as shown by the Frank J. Williams, III
r~ et al United States Patent ~,~5 ~ 9~'~ , issued ~na~ch ~Y, /~ ~/ . Additional procedures are shown in White United States Patent 3,852,242, issued December 3, 1974 and assigned to the same assignee as the present invention.
Some of the alkali metal salts of the above-des-cribed alkali phenoxides of formula (3) are sodium and potas-sium salt phenols, such as phenol, cresol, naphthol, etc,;
dihydric phenols, for example, 2,2-bis(2-hydroxyphenyl)propane;
2,4'-dihydroxydiphenylmethane;
bis(2-hydroxyphenyl)methane;

2,2-bis-(4-hydroxyphenyl)propane hereinafter identified as "bisphenol-A" or "BPA";
1,1-bis-(4-hydroxyphenyl)ethane;

11~4554 1,1-bis-(4-hydroxyphenyl)propane;
2,2-bis-(4-hydroxyphenyl)penta~e;
3,3-bis-~4-hydroxyphenyl)pentane;
4,4'-dihydroxybiphenyl;
4,4'-dihydroxy-3,3,5,5'-tetramethylbiphenyl;
2,4'-dihydroxybenzophenone;
4,4'-dihydroxydiphenylsulfone;
2,4'-dihydroxydiphenylsulfone;
4,4'-dihydroxydiphenylsulfoxide;
4,4'-dihydroxydiphenylsulfide;
hydroquinone;
resorcinol;
3,4'-dihydroxydiphenylmethane;
4,4'-dihydroxybenzophenone;
and 4,4'-dihydroxydiphenylether.
In the practice of the invention, reaction is effected between the substituted phthalimide and the phenoxide salt, which hereinafter will signify either the mono- or dihydric phenol salt in the presence of a nonpolar solvent and 2~ an effective amount of a phase tran~fer catalyst, followed by the recovery of the resulting "ether phthalimide" which here-inafter can signify either aromatic ether phthalimide, or aromatic bis(ether phthalimide). It is preferred to effect reaction under substantially anhydrous conditions, although small amounts of moisture can be tolerated.

Temperatures at which reaction between the phenoxide salt and the substituted phthalimide can be effected are in the range of about between 25C to 150C, and preferably a temper-ature between 100-120C. Any nonpolar organic solvent which RD-1~770 does not react with the reactants during the formation of the ether phthalimide can be used in the reaction. Some of the nonpolar organic solvents are, for example, toluene benzene, chlorobenzene, xylene, tetrahydrofuran, acetonitrile, octane, etc.
Experience has shown that the reaction can best be run using a solids concentration in the range of between about

5% to 150% by weight of solids, based on the total volume of non-polar solvent used, and preferably from between about~85-95% by weight. Preferably, equivalent amounts of the phenoxide salt and a substituted phthalimide can be used, while higher or lower amounts of either reactant will not substantially inter-fere with the formation of the desired ether phthalimide. In preparing the aromatic bis(ether phthalimide) there is prefer-lS ably used about 2 mols of the substituted phthalimide, per mol of the bisphenoxide salt. The phase transfer catalyst as pre-viously defined, can be utilized at from 0.005 equivalent to 2 equivalents of catalyst, per equivalent of alkali bisphenoxide and preferhbly from 0.02 to 0.05 e~uivalent.
The ether phthalimide can be recovered from the reaction mixture by a variety of procedures. One procedure, for example, can be by allowing the reaction mixture to cool, followed by recovery of the ether phthalimide by filtration.
It is preferred, however, because of the partial solubility of the ether phthalimide in various nonpolar organic solvents, to precipitate the ether phthalimide by use of a pre-cipitating solvent, for example, methanol, followed again by a standard recovery technique, such as filtration.
Alternatively, the ether phthalimide can be extracted from the reaction mixture with a better solvent such as methylene chloride, chloroform, etc., washed with water to effect removal of the inorganic salts, and recovered by the removal of the organic solvent under reduced pressure.
Experience has shown that the phase transfer catalysts and byproducts of the reaction can be recycled directly for further use in the production of ether phthalimide in accordance with the practice of the invention. For example, in the situa-tion where the reaction mixture is allowed to cool to room tem-perature to effect the separation of ether phthalimide, the filtrate can be reused as a source of the phase transfer catalyst and the nonpolar organic solvent. In instances where a precipitating solvent is employed to effect the separation of ether phthalimide, the filtrate can be evaporated to dryness to recover the phase transfer catlayst which can be recycled.
The following examples are given by way of illustra-tion and not by way of limitation. All parts are by weight and all mixtures are agitated, for example, stirred during reflux.

Example 1.
Several mixtures were prepared having tetra-butyl ammonium bromide phase transfer catalyst at different weight levels in combination with 0.9957 part of sodium 4-methyl-phenoxide, 1.578 part of 4-nitro-N-methylphthalimide, 0.4202 part of ortho-terphenyl (as an internal standard) and 14 parts of toluene. Additional mixtures were prepared having the same ingredients at the same weight levels except different phase transfer catalysts were substituted for tetra-butyl ammonium bromide. Mixtures were also prepared free of phase transfer catalyst, having as a solvent either toluene, or a dipolar aprotic solvent. The various mixtures were then ; 1144554 refluxed to produce ether phthalimide of the formula, o CH3 ~ ~ \ N-CH3 O
The result~ are shown in Table I, where "PTC" i8 phase transfer catalyst, DMSO is dimethylsulfoxide, and DMF is dimethylform-amide. __ -a~ D ~ ~ ~ Il~ 00 p,l ~r~
~ lo.l u~ O ~
,~ r ~ ¦ ~ ~ C~ ~ ~ t'd ~1 1 r~ a '~ ~ o r ~ ~ .,1 r ~ ¦ 0 ~ ~

r-~
~I r ~1 ~ lo 0 ~3 i5 o ~

o~ ~ ~ e ~

~1 S ~ ~ ~ ~ ~ .~ 'o 3 O ~1 0 _1 ~I ~ ~ O
o _~ o o ~ o ~
~ c E~
~ ~Z ~ ~ ~ ~ '~
~ ~ a~ a~ c~

1~44S54 The above results show that no reaction occurred in the absence of the phase transfer catalyst when a nonpolar solvent was used.
Example 2.
Reaction was effected between equal molar amounts of bisPhenol-A and sodium methoxide in anhydrous methanol. A
mixture of 1.99 part of the resulting sodium bisphenoxide salt, 3.02 part of 4-nitro-N-methylphthalimide, 4.71 parts of tetra-butylammonium bromide which was 2 equivalents, and about 21 ~arts of toluene, was heated at reflux under nitrogen for 22 hour~. ~he reaction mixture was cooled to room temperature and waq extracted with a mixture of methvlene chloride and 1.2 normal HCl. The resulting organic solution was dried and concentrated. The resulting mixture was stirred with methanol and filtered resulting in 2 35 parts of an ether phthalimide of the formula, o having a meltin~ ~oint of 145-147C.
Exam~le 3, A mixture of 6.01 parts of the sodi~m salt of bis-phenol-A, 9;15 parts of 4-nitro-N-methylphthalimide, 1.78 part of tetrabutylammonium bromide and about 39 parts of toluene was refluxed under nitrogen for 40 minutes. The mixture was then allowed to cool to ambient conditions and then diluted with about 96 parts of methanol. A precipitate was formed which was recovered by filtration and washed with methanol. There 1~4554 was obtained 11.2 parts of product or a 93~ yield having a melting point of 146.5-148C. Based on method of pre~ration the product was the ether phthalimide of formula (2). The filtrate and the washes were combined and concentrated and the resulting solid was dried under reduced pressure at 105C for 1/2 hour.
The mixture of 5.9 parts of the sodium salt of bis-phenol-A, 8.98 parts of 4-nitro-N-methylphthalimide,5 parts of the catalyst residue recovered above and about 37 parts of toluene was heated at reflux for 40 minutes. There was obtained a 95~ yield of the ether phthalimide of bisphenol-A as previously defined having the same melting point. The filtrate and the washings were again recovered and concentrated following the above procedure to salvage the phase transfer catalyst for further use in the production of aromatic ether phthalimide.
It was found that the yield of the ether phthalimide remained sub~tantially unchanged over several additional runs using the same recycled catalyst.
Exam le 4.
P
An evaluation of the effectiveness of various phase transfer catalysts was made to determine the optimum catalyst and the optimum concentration for effecting the nitro displace-ment of 4-nitro-N-methylphthalimide with sodium cresoxide in toluene. There was utilized an equal molar amount of the reactants in the mixture and the phase transfer catalyst was utilized at 0.1 equivalent, based on the mols of the sodium phenoxide salt employed. T~e weight percent yields of ether phthalimide are listed under "Toluene refluxing time in Hr."
and "PTC" is defined as in Example 1.

119~4~54 Table II
P T C (Toluene refluxing Lo~ L~
~ 6.0 None 0 (CH3)4 ~ ~ 0.6 4 13 20 27 (C2H5)~ ~ ~ 3 4 8 13 32 (n~C3H7)4 ~ 63 70 75 76 (C4~-9)4 ~ ~ 68 73 85 93 96 (C4Hg)4 ~C1~ 72 74 78 81 82 (C4Hg)4 ~ 24 32 40 45 54 (C4Hg)4 ~ 56 70 74 82 93 (C4Hg)4 ~ (~XH20) 11 17 30 36 48 (C4Hg)4 ~ 20 27 36 39 50 (Hexyl)4 ~C1~ 47 51 61 67 74 (Heptyl)4 ~C ~ 53 66 72 78 82 Ali~uat 336 17 29 39 42 46 Adogen 464 30 39 47 52 57 (C2H5)3 ~CH2(C6H5) 13 13 13 13 CH3(cH2)ls ~(CH3)3B ~ 15 17 24 25 32 (C4H9)4 ~ ~ 17 21 25 28 33 (C6H5)3 ~CH3B 1 2 2 2 4 (C6H5)3 ~CH2(C6H5)9r~ 2 2 2 3 5 (C4Hg)4 ~C1~3 . 20 30 33 38 44 Dibenzo-18-crown-6 19 27 35 S0 56 15-crown-15 49 54 62 64 68 (C4Hg)4 ~ Ac~ XH20) 3 9 21 27 42 The above results show that tetrabutylammonium bromide and tetrabutylammonium fluoride provide the highest weight percent yields of ether phthalimide.

~ 4SS4 Example 5.
A mixture of 62.54 parts of anhydrous disodium bisphenol-A, 94.9 parts of 4-nitro-N-methylphthalimide, 18.51 parts of tetrabutylammonium bromide and 366 parts of toluene was heated at reflux for 1.5 hour. The mixture was cooled to 25C and diluted with 1200 parts of methanol. There was obtained a precipitate which was collected, reslurried with methanol and dried to provide 94 parts of product which represented a 94% yield. Based on method of preparation, the product was 2,2-bi~[4-(N-methylphthalimide-4-oxy)phenyl]-propane.
The above reaction was repeated using increasing solids levels and decreasing amounts of catalyst. The follow-ing results were obtained, where the amounts indicated are in parts,unless otherwise shownr "BPA" is bisphenoxide ion,"4-NPI"
is 4-nitrophthalimide, and BPA-BI is the bisetherimide named above.

11~4554 ~I H
~ m o~ ~ o~ cn P~
d~ m H
m ,1 0 ,I r a~
oo o ~ U o m _~

P~ ~
z m ~ a~ Ln o ~ ~, o O O
U~ o o o o o ~ ,t H 0 ~1 ..
H ~ a~ ..
H ~

E~
~ _ ~- co o o n O--~ ~

::~ ~'1 ~ N _I
~0 ~ .
E~

H O O 1~ o ~1 a~ N ~ Il~ t~
æ ~ O

~ ~ I~ ~O O
!l u~
¢ ~ u~ co a~
m ~9 The above results show that increasing solids concen-tration can markedly influence the amount of catalyst required.
Example 6.
A mixture of 6.01 parts of the disodium salt of bisphenol-A, 9.1S parts of 4-nitro-N-methylphthalimide, different amounts of tetrabutylammonium bromide and about 38 parts of toluene, which amounted to about 35% solids, was refluxed under a nitrogen atmosphere for a period of form 0.5 to 6 hour.s. The results shown in Table IV illustrate the importance of catalyst level at a given solids concentration.
Table IV
Eq . P. T . C . /1 Eq. BPA ~ Displacement 0.8 89 0.6 93 0.4 92 0.2 93 0.1 63 Example 7.
A mixture of 1.1301 part of bisphenol-A dianion, 1.5013 parts of 4-fluoro-N-methylphthalimide, 0.3346 parts Bu4N Br (0.25 eq./eq. bisphenol-A dianion) and 7.7 parts of toluene amounting to 30~ solids was stirred under nitrogen at reflux for 2-1/2 hours. The reaction mixture was cooled to 25C, diluted with methanol and filtered to give 1.91 part or an 86% yield of product having a melting point of 147-149C.
Based on method of preparation, the product was 2,2-bis[4-(N-methylphthalimide-4-oxy)phenyl]propane.

~ 4554 RD-10770 Additional bisimides were prepared utilizing phthal-imides of the formula, ~ \

in a similar manner as shown in Table V below:
Table V
BPA Salt X RTime (hr.) % Yield MP C (Lit) 4-NO2 C6H5 1 hr. 86 211-212 (211-213) 3-NO2 C6H5 1 hr. 86 203-204.5 (203-204.5) 3-NO2 CH3 1 hr. 89 206.5-207.5 Example 8.
Example 6 was repeated using 0.25 equivalents of tetrabutylammonium chloride in place of the bromide to obtain a 92% yield of the desired bisimide. In a similar fashion, the reaction was repeated using 0.25 equivalents of Aliquat 336 to give a 60% yield of 2,2-bis[4-(N-methylphthalimide-4-oxy)phenyl]-propane.
Example 9.
Anhydrous bisphenol-A disodium salt was generated by azeotropically removing water from the hexahydrate, A mixture of 11.81 parts of the bisphenol-A hexahydrate and 35 parts of toluene was refluxed until all traces of water had been removed by azeotropic distillation. To this mixture was added 12.33 parts of 4-nitro-N-methylphthalimide and 1.06 part of tetrabutylammonium bromide. The reaction mixture was heated at reflux for 1 hour and worked up as described in Example 5 1~45S4 to give 15.1 parts (92% yield) of the corresponding bisimide.
The above reaction is repeated, except that xylene is used in place of toluene. There is obtained substantially 8 imilar results.
Toluene is used as an azeotroping solvent to make the above described bisimide, by the same procedure, except that the mixture is allowed to cool to 25C and filtered. The resulting solid is thereafter washed with 5 ml of hot toluene and methanol to obtain a high yield of the desired bisimide.
Example 10.
A mixture of 2.95 parts of bisphenol-A dianion, 4.67 parts of 4-nitro-~-methylphthalimide, 0.697 g of Bu4N+Br and 43.3 parts of toluene was heated at reflux under nitrogen for 4 hours. The reaction mixture was cooled to 25C and diluted with 266 parts of methylene chloride. The solution was extracted with water and the organic solution was dried and concentrated to give after a methanol and water wash, 6.6 parts or a 95~ yield of the corresponding bisimide.
Although the above examples are directed to only a few of the parameters which can be used in the practice of the method of the present invention, it should be understood that the present invention is directed to a much broader method of making aromatic ether imides as shown by the disclosure preceding these examples.

Claims (15)

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

1. A method for making aromatic ether imides of the formula, which comprises (A) heating at 25° to 150°C. under substantially anhydrous conditions, a mixture consisting essentially of substituted phthalimide of the formula, and an alkali metal phenoxide salt of the formula, R1-OM).alpha., in the presence of a nonpolar organic solvent and an effective amount of a phrase transfer catalyst of the formula, (R2)4Qy, (B) agitating the resulting mixture with a precipitating or extractive organic solvent for the resulting bisimide or allowing the mixture to cool and (C) recovering the bisimide from the mixture of (B), where R is a monovalent group selected from hydrogen, a C(1-8) alkyl group, a C(6-13)aryl group and a C(6-13)haloaryl group, R1 is an aromatic group selected from the group consisting of a C(6-30) aromatic carbocyclic group, a halogenated C(6-30) aromatic carbocyclic group and an alkylated C(6-30) aromatic carbocyclic group and a divalent organic group of the formula, where X is a member selected from the group consisting of divalent groups of the formula, , , -O-, and -S-, m is 0 or 1, y is a whole number from 1 to 5, R is selected from a C(1-16) alkyl radical and a C(6-13) aromatic carbocyclic radical, Q is a Group Va element selected from N and P, Y is a halogen of carbethoxy radical, X1 is a member selected from the group consisting of nitro and halo, and a is an integer equal to 1 or 2, and when a is 1, R1 is monovalent and when a is 2, R1 is divalent.

2. A method in accordance with claim 1, utilizing an alkali metal monophenoxide salt.

3. A method in accordance with claim 1, utilizing an alkali metal diphenoxide salt.

4. A method in accordance with claim 1, where the alkali metal salt is the anhydrous disodium salt of bisphenol-A.

5. A method in accordance with claim 1, where the alkali metal phenoxide salt is made by azeotroping water from a mixture of toluene and the hydrated form of the alkali metal phenoxide salt.

6. A method in accordance with claim 1, where the alkali metal phenoxide salt is formed in situ from an aqueous mixture of the alkali metal hydroxide and the corresponding phenol.

7. A method in accordance with claim 1, where the alkali metal phenoxide salt is made from a mixture of an alkali metal alkoxide and the corresponding monohydric or dihydric phenol.

8. A method in accordance with claim 1, where Y
in the phase transfer catalyst is chloride.

9. A method in accordance with claim 1 where the phase transfer catalyst is methyl tricapryl ammonium chloride.

10. A method in accordance with claim 1, where the substituted phthalimide is 3-nitro-N-methylphthalimide.

11. A method in accordance with claim 1, where the substituted phthalimide is 4-fluoro-N-methyl phthalimide.

12. A method in accordance with claim 1, where the substituted phthalimide is a nitro-N-methyl or N-phenyl phthalimide.

13. A method in accordance with claim 1, where the alkali metal phenoxide is an alkali bisphenoxide of a dihydric sulfone .

14. A method in accordance with claim 1, where the alkali metal phenoxide is an alkali bisphenoxide of a dihydric sulfide.

15. A method for making an ether phthalimide of the formula, which comprises (A) heating at 25°C. to 150°C. under substantially anhydrous conditions 4-nitro-N-methylphthalimide and the disodium salt of bisphenol-A in the presence of toluene and an effective amount of tetrabutyl ammonium bromide.
(B) agitating the resulting mixture with a precipating or extractive organic solvent for said bisimide or allowing the mixture to cool and (C) recovering the bisimide from the mixture of (B).