Method for preparing dianhydride

Abstract

The present invention relates to a method for preparing a dianhydride, comprising contacting an N-substituted diimide with a carboxylic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium to provide a reaction mixture comprising a tetraacid, a triacid, an imide diacid and a diimide and substituted or unsubstituted acetic acid, dimethyl sulfoxide and derivatives thereof. The method comprises separating the tetraacid by precipitation in water followed by centrifuge or filtration. The tetraacid is converted into the corresponding dianhydride. The dianhydride prepared by the method is also described as a precursor for preparing polyetherimides.

Description

[0001] Priority declaration

[0002] This application claims the benefit of priority to the following applications:

[0003] U.S. Provisional Application Serial No. 63 / 036486 filed on June 9, 2020;

[0004] Each of which is incorporated herein by reference. Technical Field

[0005] The present invention generally relates to the field of processes for making dianhydrides, which are intermediates in the manufacture of polyetherimides. Background Art

[0006] Dianhydrides are key intermediates in the manufacture of polyimides (PI), especially polyetherimides (PEI). PEI is an amorphous, transparent, high-performance polymer with a glass transition temperature greater than 180°C. These polymers are known to have high strength, heat resistance, modulus, and broad chemical resistance. Due to these characteristics, PEI is widely used in different applications such as automotive, telecommunications, aerospace, electronics / electrical, transportation, and healthcare. Polyetherimides are manufactured by polycondensation of dianhydrides and diamines. Dianhydrides are manufactured in various ways. The preparation of dianhydrides from diimides is one of the most commonly used processes. For example, dianhydrides can be prepared from aromatic diimides such as N-substituted bisphenol A diimide (5,5'-((propane-2,2-diylbis(4,1-phenylene))bis(oxy))bis(2-methylisoindoline-1,3-dione)), which has the following structure.

[0007]

[0008] Other variations of the imide may also exist.Imides such as 1 can in turn be produced by a displacement reaction typically between a bisphenol such as bisphenol-A or a biphenol and a substituted phthalimide such as nitro- or halo-N-methylphthalimide with the aid of a base.

[0009] Conventionally, the conversion of imide to dianhydride is usually carried out by two main processes. One process involves a two-step protocol; alkaline hydrolysis of the imide, followed by acidification to prepare the tetraacid, which is then cyclized to prepare the dianhydride. The other process involves an exchange reaction of the imide with phthalic anhydride in an aqueous medium in the presence of triethylamine to form a tetraacid, which is then cyclized to produce the dianhydride. The latter process is an incomplete conversion of the imide to the dianhydride, which requires extraction with an organic solvent to purify the tetraacid, and recycling of the unreacted imide and other byproducts.

[0010] Simon Padmanabhan in WO 2019 / 245898 A1, Aaron Royer in WO 2019 / 222077 A1 and WO 2017 / 189293 A1, Robert Werling in WO 2019 / 236536 A1, Gregory Hemmer in WO 2019 / 217257 A1, Jimmy Webbs in US 4,329,496 and US 4,318,857, Brent Dellacoletta in US 6,008,374 and US 5,536,846, Darrel Heath in US 3,879,428 and US 3,957,862, and James Silva in US 4,571,425 generally reported the synthesis of dianhydrides from diimides by exchange reactions in aqueous media. However, their method has low yield and requires the use of organic solvents at high temperature and pressure for separation and recycling of materials. James Schulte reported the synthesis of dianhydrides from diimides in WO 2017 / 172593A1 as a whole. However, their method uses a multi-step protocol of alkaline hydrolysis and acidification, which is unrelated to the reagents and protocols used in the present invention.

[0011] Therefore, there remains a need for an improved process for making and isolating dianhydrides from diimides in a single step that provides high yields and does not require purification and avoids multi-step alkaline hydrolysis followed by acidification protocols. Summary of the invention

[0012] The present invention recognizes that there is a long-standing need for processes for synthesizing dianhydrides and the products of these processes.

[0013] A first aspect of the present invention is generally directed to a method for synthesizing a dianhydride.

[0014] A second aspect of the present invention is generally directed to dianhydrides prepared by the process of the present invention.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016] none DETAILED DESCRIPTION

[0017] definition

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the invention belongs. In general, the terms used herein and the laboratory procedures in cell culture, chemistry, microbiology, molecular biology, cell science, and cell culture described below are well known and commonly used in the art. Conventional methods are used for these procedures, such as those in the art and various general references, such as, but not limited to, the methods provided in WO 2019 / 245898 A1 and WO 2017 / 172593 A1. Where a term is provided in singular form, the inventors also consider the plural form of the term; and where a term is provided in plural form, the inventors also consider the singular form of the term. The terms used herein and the laboratory procedures described below are well known and commonly used in the art. The following terms used throughout this disclosure, unless otherwise stated, should be understood to have the following meanings:

[0019] All scopes disclosed herein are connected head to tail, and the head and tail can be combined independently of each other." Combination " includes blends, mixtures, alloys, reaction products, etc. The terms "first", "second", etc. do not represent any order, quantity or importance, but are used to represent a kind of element from other elements. The terms "one", "one" and "the" do not represent the limitation of quantity, and will be interpreted as covering both singular and plural, unless otherwise specified herein or obviously contradictory with the context. "Or" means "and / or", unless otherwise clearly specified. References to "some embodiments", "one embodiment", "some aspects", "one aspect", etc. throughout the specification refer to the specific elements described in conjunction with the embodiments or aspects being included in at least one embodiment or aspect described herein, and may or may not exist in other embodiments or aspects. In addition, it should be understood that in various embodiments or aspects, the described elements can be combined in any suitable manner.

[0020] Unless otherwise defined, technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. All cited patents, patent applications and other references are incorporated herein by reference in their entirety. However, if a term in this application contradicts or conflicts with a term incorporated in a reference, the term in this application takes precedence over the conflicting term incorporated in the reference.

[0021] Compounds are described using standard nomenclature. For example, any position substituted by any indicated group is understood to have its valence filled with the indicated bond or hydrogen atom. A dash not between two letters or symbols is used to indicate the point of attachment of a substituent. For example, -CHO is connected to the carbon of a carbonyl group. The term "hydrocarbyl", whether used alone or as a prefix, suffix or fragment of another term, refers to a residue containing only carbon and hydrogen. The residue can be aliphatic or aromatic, straight chain, cyclic, bicyclic, branched, saturated or unsaturated. It can also include a combination of aliphatic, aromatic, straight chain, cyclic, bicyclic, branched, saturated and unsaturated hydrocarbon parts. However, when a hydrocarbyl residue is described as being substituted, it can optionally include heteroatoms above and above the carbon and hydrogen members of the substituent residue. Therefore, when specifically described as being substituted, the hydrocarbyl residue can also include one or more carbonyl groups, amino groups, hydroxyl groups, etc., or it can include heteroatoms in the main chain of the hydrocarbyl residue. The term "alkyl" refers to a branched or straight chain saturated aliphatic hydrocarbon group, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, n-hexyl and sec-hexyl. The term "alkenyl" refers to a straight or branched chain monovalent hydrocarbon group having at least one carbon-carbon double bond. The term "alkoxy" refers to an alkyl group attached through oxygen, such as methoxy, ethoxy and sec-butoxy groups.

[0022] Although specific embodiments and aspects have been described, substitutions, modifications, variations, improvements, and substantial equivalents that are not currently foreseen or may not be foreseen may occur to the applicant or other skilled in the art. Therefore, the appended claims and the claims as they may be amended are intended to include all such substitutions, modifications, variations, improvements, and substantial equivalents. The term "alkylene" refers to a straight or branched, saturated, divalent aliphatic hydrocarbon group (e.g., methylene (-CH2-) or ethylene (-CH2CH2-)). Cycloalkylene refers to a divalent cyclic alkylene group, C n H 2n-2 -. "Cycloalkenyl" refers to a monovalent group having one or more rings and one or more carbon-carbon double bonds in the rings, wherein all ring members are carbon (e.g., cyclopentenyl, cyclohexenyl). "Aryl" refers to an aromatic hydrocarbon group containing a specified number of carbon atoms, such as phenyl, cycloheptatrienol, indanyl, or naphthyl. "Arylene" refers to a divalent aromatic group. "Arylenealkyl" refers to an arylene group substituted by an alkyl group. The prefix "halo" refers to one or more fluorine-, chlorine-, bromine-, or iodine-substituents in a group or compound. The prefix "hetero" refers to a compound or group containing heteroatoms N, O, S, P, or Si. "Substituted" means that a compound or group is substituted by at least one (e.g., 1, 2, 3, or 4) substituent, each of which may independently be C 1-9 Alkoxy, C 1-9Halogen, nitro (-NO2), cyano (-CN), C 1-6 Alkylsulfonyl (-SCH-alkyl), C 3-12 Arylsulfonyl (-SO2-aryl), thiol (-SH), thiocyanate (-SCN), tolyl (CH3C6H4SO2-), C 3-12 Cycloalkyl, C 5-12 Cycloalkenyl, C 6-12 Aryl, C 7-13 Arylene alkyl, C 4-12 Heterocycloalkyl and C 3-12 A heteroaryl group replaces a hydrogen provided that the normal valence of the substituted atom is not exceeded. The number of carbon atoms indicated in the group does not include any substituents. For example, -CH2CH2CN is a C2 alkyl group substituted with a nitrile group.

[0023] "Direct" refers to direct cause and effect relationships that do not require intermediate steps.

[0024] "Indirect" refers to indirect causal relationships that require intermediate steps.

[0025] Other technical terms used herein have ordinary meanings in the technologies in which they are used, as exemplified by various technical dictionaries.

[0026] introduction

[0027] The present invention recognizes that there is a long-standing need for processes for synthesizing dianhydrides and the products of these processes.

[0028] As a non-limiting introduction to the breadth of the invention, the invention comprises several general and applicable aspects, including:

[0029] 1) A method for synthesizing dianhydride; and

[0030] 2) A dianhydride prepared by the method of the present invention.

[0031] These aspects of the invention, as well as other aspects described herein, can be achieved using the methods, articles and material compositions described herein.To gain a comprehensive understanding of the scope of the invention, it will be further appreciated that various aspects of the invention can be combined to form desired embodiments and aspects of the invention.

[0032] I. Method for preparing dianhydride composition

[0033] The present invention comprises a method for synthesizing a dianhydride composition.

[0034] Generally, the process for synthesizing the dianhydride composition of the present invention comprises contacting an N-substituted diimide with an organic carboxylic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium under conditions effective to provide an aqueous reaction mixture comprising a high conversion of the tetraacid as well as the triacid and the imidic diacid, wherein the reaction is conducted at a reaction temperature of from about 150° C. to about 250° C. and a reaction pressure of from about 150 psig to about 300 psig; precipitating the product in water; and converting the tetraacid to the corresponding dianhydride by heating or any other conventional method.

[0035] The present invention provides a method for directly converting imides to dianhydrides. In particular, the inventors have found that the use of substituted or unsubstituted acetic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium can directly convert imides to tetraacids in high yields, which can be isolated by precipitation in water, and the precipitated tetraacid can be cyclized to dianhydrides by heating.

[0036] The method comprises reacting an imide with substituted or unsubstituted acetic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium under conditions effective to provide an aqueous reaction mixture.

[0037] Conventionally, the conversion is carried out with phthalic anhydride, water and triethylamine, yielding conversions as high as 80%. This requires a purification protocol involving solvent extraction using flammable organic solvents at elevated temperatures and pressures.

[0038] Another general method involves a multi-step protocol of alkaline hydrolysis followed by acidification and possible purification at each step, followed by ring closure to prepare the dianhydride.

[0039] The starting imide may have the formula (2)

[0040]

[0041] Where A is -O-, -S-, -C(O)-, -SO2-, -SO-, -C y H 2y -(wherein y is an integer from 1 to 5) or a halogenated derivative thereof or -OEO-, wherein E is optionally substituted by 1 to 6 C 1-8 Alkyl groups, aromatic C 6-24 A monocyclic or polycyclic moiety, or a combination comprising at least one of the foregoing.

[0042] In one aspect of the present invention, R is a monovalent C 1-13 Organic group.

[0043] In one aspect of the invention, the group A in formula (2) is a substituted or unsubstituted divalent organic bond of -O- or -OEO- groups located at the 3,3', 3,4', 4,3' and 4,'4 positions. Exemplary E groups include groups of formula (3):

[0044]

[0045] Where R a and R b Each independently is a halogen atom or a monovalent C 1-6 alkyl groups, and may be the same or different; m and n are each independently an integer from 0 to 4; c is 0 to 4, specifically 0 or 1; and Z a is a bridging group connecting two aromatic groups, wherein the connection points of the bridging group and each C6 arylene group are located at the ortho position, meta position or para position (especially para position) on the C6 arylene group. a It can be a single bond, -O-, -S-, -S(O)-, -S(O)2-, -C(O)- or C 1-18 Organic bridging group. 1-18 The organic bridging group may be cyclic or acyclic, aromatic or non-aromatic, and may also include heteroatoms such as halogens, oxygen, nitrogen, sulfur, silicon or phosphorus. 1-18 The organic group may be arranged so that the C6 arylene groups attached thereto are each attached to a common alkylidene carbon or to a C 1-18 The organic bridging group has different carbon atoms. Specific examples of group E are divalent groups of formula (4):

[0046]

[0047] Where L is a single bond, -O-, -S-, -C(O)-, -SO2-, -SO-, -P(R a )=O)-(where R a C 1-18 Alkyl or C 6-12 Aryl) or -C y H 2y-, wherein y is an integer from 1 to 5 or a halogenated derivative thereof (including a perfluoroalkylene group). Exemplary dihydroxy aromatic compounds from which E can be derived include, but are not limited to, 2,2-bis-(2-hydroxyphenyl)propane, 2,4'-(dihydroxydiphenylmethane, bis(2-hydroxyphenyl)methane, 2,2-bis-(4-hydroxyphenyl)propane (also known as bisphenol A or BP A), 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'-tetramethylbiphenyl, 2,4'-hydroxybenzophenone, 4,4'-dihydroxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, hydroquinone, resorcinol, 3,4-dihydroxydiphenylmethane, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl ether, etc., or a combination including at least one of the above.

[0048] In one aspect of the invention, E is derived from bisphenol A, such that L in the above formula is 2,2-isopropylidene.

[0049] Thus, in one aspect of the invention, E is 2,2-(4-phenylene)isopropylidene (5).

[0050]

[0051] In one aspect of the invention, E is derived from a biphenol such that L in the above formula is a single bond.

[0052] Therefore, in one aspect of the present invention, E is 4-phenylene-1,1'-biphenyl (6)

[0053]

[0054] In one aspect of the invention, R is a phenyl group or a C 1-4 The alkyl group is, for example, a methyl group, an ethyl group, a propyl group or a butyl group, preferably a methyl group.

[0055] In one aspect of the present invention, the imide comprises 4,4'-bisphenol A bis-N-methylphthalimide, 3,4'-bisphenol A-bis-N-methylphthalimide, 3,3'-bisphenol A-bis-N-methylphthalimide, 4,4'-biphenol-bis-N-methylphthalimide, 3,3'-biphenol-bis-N-methylphthalimide, or a combination comprising at least one of the foregoing.

[0056] The carboxylic acid may have the formula

[0057] X-COOH

[0058] Wherein X is a substituted or unsubstituted phenyl group, hydrogen, a monovalent C 1-6 An alkyl group, a halogen-substituted alkyl group or a halogen.

[0059] In one aspect of the invention, the carboxylic acid is preferably acetic acid.

[0060] In one aspect of the present invention, the substituted or unsubstituted acetic acid is preferably acetic acid.

[0061] The substituted or unsubstituted dimethyl sulfoxide may have the formula

[0062] J2SO

[0063] Wherein the two Js may be the same or different. J is a substituted or unsubstituted phenyl, hydrogen, a monovalent C 1-5 An alkyl group or a halogen-substituted alkyl group.

[0064] In one aspect of the present invention, the substituted or unsubstituted dimethyl sulfoxide is preferably dimethyl sulfoxide.

[0065] The imide is reacted with substituted or unsubstituted acetic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium.

[0066] The reaction is further carried out under conditions effective to provide an aqueous reaction mixture. Effective conditions may include reacting at a reaction temperature of about 150°C to about 250°C, such as about 160°C to about 210°C, and at a reaction pressure of about 160 psig to about 300 psig, such as about 180 psig to about 240 psig.

[0067] In one aspect of the invention, the initial mass ratio of acetic acid to imide is between about 0:1 and about 10:1.

[0068] In one aspect of the present invention, the initial mass ratio of dimethyl sulfoxide to imide is between about 1:1 and about 10:1.

[0069] In one aspect of the invention, the initial aqueous reaction mixture has less than about 10 wt%, less than about 15 wt%, less than about 20 wt%, or less than about 25 wt%.

[0070] The aqueous reaction resulting from the reaction of the imide with substituted or unsubstituted acetic acid and substituted or unsubstituted dimethyl sulfoxide comprises a tetraacid, at least one triacid and an imide diacid.

[0071] In one aspect of the invention, the tetraacid has the formula

[0072]

[0073] The triacid has the formula

[0074]

[0075] The imide diacid has the formula

[0076]

[0077] Wherein A can be as described above, and is preferably -O-, -S-, -C(O)-, -SO2-, -SO-, -CyH2y- (wherein y is an integer from 1 to 5) or a halogenated derivative thereof or -OEO-, wherein E is optionally substituted by 1 to 6 C 1-8 Alkyl groups, aromatic C 6-24 A monocyclic or polycyclic moiety, or a combination comprising at least one of the foregoing. R is a phenyl group or C 1-4 The alkyl group is, for example, a methyl group, an ethyl group, a propyl group or a butyl group, preferably a methyl group.

[0078] In one aspect of the invention, A is -OEO-, wherein E is derived from bisphenol A or biphenol. The divalent bond of the -OEO- group is located at the 3,3', 3,4', 4,3' or 4,4' position.

[0079] In one aspect of the invention, the aqueous reaction mixture may further include an imide. Without wishing to be bound by theory, the reaction mixture may further include acetic acid and its derivatives derived from the reaction, and substituted and unsubstituted dimethyl sulfoxide, derivatives of substituted or unsubstituted dimethyl sulfoxide, and decomposition products of substituted or unsubstituted dimethyl sulfoxide derived from the reaction.

[0080] The method also includes isolating the tetraacid containing the mixture of the triacid, the imide diacid and the diimide by precipitating the reaction mixture in water at a relatively low temperature.

[0081] In one aspect of the invention, the volume ratio of water added to the reaction mixture is between about 10:1 and about 1:1.

[0082] In one aspect of the invention, precipitation is carried out at a temperature between about 5°C and about 50°C.

[0083] In one aspect of the invention, precipitation can be performed at a temperature between about 5°C and about 50°C without the addition of water.

[0084] The method further comprises removing the aqueous phase by filtering or centrifuging the aqueous slurry to obtain a cake of a mixture of the tetraacid, triacid, and imide diacid and diimide.

[0085] The method also includes converting the tetraacid to the corresponding dianhydride. The conversion of the tetraacid to the corresponding dianhydride can be easily determined by common techniques in the art, such as a cyclization process using water formation.

[0086] In one aspect of the invention, the precipitate of the tetraacid is converted to the dianhydride by heating at a temperature between about 140° C. and about 220° C. and a pressure of less than about 200 mm / Hg. Alternatively, the tetraacid is converted to the dianhydride by refluxing in the presence of a dehydrating agent such as acetic anhydride.

[0087] In one aspect of the invention, the crude reaction mixture of the tetraacid is converted to the dianhydride by heating at a temperature between about 140°C and about 220°C and a pressure of less than about 200 mm / Hg.

[0088] Dianhydrides can be used to make polyimides, particularly polyetherimides. Polyetherimides can be prepared by any of the well-known techniques in the art. A common method for preparing polyetherimides from dianhydrides is to prepare polyetherimides from a dianhydride of formula (10):

[0089]

[0090] Reaction with diamine of the following formula

[0091] H2N-R'-NH2

[0092] Wherein, each R' is independently the same or different, substituted or unsubstituted divalent organic group, such as C 6-20 Aromatic hydrocarbon groups or halogenated derivatives thereof, linear or branched alkylene groups or halogenated derivatives thereof, C 3-9 Cycloalkylene groups or halogenated derivatives thereof, in particular divalent groups of one or more of the following formulae:

[0093]

[0094] Where Q is -O-, -S-, -C(O)-, -SO2-, -SO-, -P(T)(=O)- (where T is C 1-8 alkyl or aryl), -C y H 2y -(wherein y is an integer from 1 to 5) or a halogenated derivative thereof (which includes a perfluoroalkylene group), or -(C6H 10 ) z -, wherein z is an integer from 1 to 4.

[0095] In some aspects of the present invention, R' is m-phenylene, p-phenylene or diarylene sulfone, in particular 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.

[0096] Examples of the organic diamines include ethylenediamine, propylenediamine, trimethylenediamine, diethylenediamine, triethylenetetramine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, decamethylenediamine, 1,12-dodecamethylenediamine, 1,18-octadecamethylenediamine, 3-methylheptamethylenediamine, 4,4-dimethylpentamethylenediamine, 4-methylnonamethylenediamine, 5-methylnonamethylenediamine, 2,5-dimethylheptamethylenediamine, 2,2-dimethylpropylenediamine, N-methyl-bis(3-aminopropyl)amine, 3-methoxyhexamethylenediamine, 1,2-bis(3-aminopropoxy)ethane, bis(3-aminopropyl)sulfide, 1,4-cyclohexanediamine, bis(4-aminocyclohexyl)methane, m-phenylenediamine, p-phenylenediamine, 2 ,4-diaminotoluene, 2,6-diaminotoluene, m-xylene diamine, p-xylene diamine, 2-methyl-4,6-diethyl-1,3-phenylenediamine, 5-methyl-4,6-diethyl-1,3-phenylenediamine, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 1,5-diaminonaphthalene, bis(4-aminophenyl)methane, bis(2-chloro-4-amino-3,5-diethylphenyl)methane, bis(4-aminophenyl)propane, 2,4-bis(p-amino-tert-butyl)toluene, bis(p-amino-tert-butylphenyl)ether, bis(p-methyl-o-aminophenyl)benzene, bis(p-methyl-o-aminopentyl)benzene, 1,3-diamino-4-isopropylbenzene, bis(4-aminophenyl)sulfide, bis(4-aminophenyl)sulfone and bis(4-aminophenyl)ether. Combinations of these compounds may also be used.

[0097] In some aspects of the present invention, the organic diamine is m-phenylenediamine, p-phenylenediamine, sulfonyl dianiline, or a combination comprising one or more of the foregoing.

[0098] Copolymers of polyimides can be made using a combination of an aromatic dianhydride of formula (10) and a different dianhydride (eg, where A does not contain ether functionality, such as a dianhydride where A is a sulfone). Illustrative examples of dianhydrides that can be prepared by the above method or used to prepare the polyimide include 3,3-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride, 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride, Phenyl sulfide dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfone dianhydride, 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl-2.2-propane dianhydride, 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl ether dianhydride, 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)benzophenone dianhydride, and 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride, and various combinations thereof.

[0099] Aspects and embodiments of the invention

[0100] A first aspect of the invention comprises a method for preparing a dianhydride comprising reacting a substituted diimide with a carboxylic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium under conditions to provide a reaction mixture comprising a tetraacid, a triacid and an imide diacid, wherein the reaction temperature is between about 160° C. and about 250° C., and the reaction pressure is between about 150 psig and about 300 psig, preferably between about 170 psig and about 250 psig; removing the sulfoxide, carboxylic acid and other by-products by precipitation in water; filtering the precipitate; and converting the tetraacid precipitate to the corresponding dianhydride; wherein

[0101] The imide has the formula

[0102]

[0103] The carboxylic acid has the formula X-COOH

[0104] Sulfoxide has the formula J2SO

[0105] The tetraacid has the formula

[0106]

[0107] The triacid has the formula

[0108]

[0109] The diacid imide has the formula

[0110]

[0111] The dianhydride has the formula

[0112]

[0113] In the above formula

[0114] A is -O-, -S-, -C(O)-, -SO2-, -SO-, -C y H 2y -(wherein y is an integer from 1 to 5) or a halogenated derivative thereof or -OEO-, wherein E is optionally substituted by 1 to 6 C 1-8 Alkyl groups, aromatic C 6-24 A monocyclic or polycyclic moiety, or a combination comprising at least one of the foregoing.

[0115] R is a monovalent C 1-13 Organic groups;

[0116] X is an aryl group, C 1-8 An alkyl group, or preferably a methyl group.

[0117] J is C 1-8 An alkyl group or an aryl group, preferably a methyl group.

[0118] Another aspect of the present invention includes wherein E is 2,2-(4-phenylene)isopropylidene.

[0119]

[0120] Another aspect of the present invention includes wherein E is 4-phenylene-1,1'-biphenyl.

[0121]

[0122] Another aspect of the present invention includes wherein the initial mass ratio of acetic acid to imide is between about 1:1 to about 50:1, or about 1:1 to about 20:1, or about 1:1 to about 10:1.

[0123] Another aspect of the present invention includes wherein the initial mass ratio of dimethyl sulfoxide to imide is between about 1:1 to about 50:1, or about 1:1 to about 20:1, or about 1:1 to about 10:1.

[0124] Another aspect of the present invention includes wherein the initial mass ratio of water to imide is between about 1:1 to about 100:1, or about 2:1 to about 50:1, or about 2:1 to about 20:1.

[0125] Another aspect of the present invention includes wherein the reaction mixture further comprises imide, acetic acid and its derivatives and dimethyl sulfoxide and reaction and decomposition products thereof.

[0126] Another aspect of the present invention includes wherein the precipitation is performed by adding to water.

[0127] Another aspect of the present invention includes wherein the precipitation is performed by cooling the reaction mixture to between about 5°C and about 50°C.

[0128] Another aspect of the present invention includes wherein the ratio of reaction mixture to water used for precipitation is between about 1:0 to about 1:10.

[0129] Another aspect of the present invention includes wherein the precipitate is heated at 180°C to 250°C under reduced pressure of less than about 200 mm / Hg with or without a dehydrating agent.

[0130] Another aspect of the present invention includes wherein the reaction mixture is directly converted to the dianhydride by heating at between about 180°C to about 250°C under reduced pressure of less than about 200 mm / Hg with or without a dehydrating agent.

[0131] Another aspect of the present invention includes wherein the conversion of the imide to the dianhydride is at least about 90%, preferably at least about 96%.

[0132] Another aspect of the present invention includes, wherein the diimide includes 4,4'-bisphenol A-bis-N-methylphthalimide, 3,4'-bisphenol A-bis-N-methylphthalimide, 3,3'-bisphenol A-bis-N-methylphthalimide or a combination including at least one of the foregoing; the dianhydride includes 4,4'-bisphenol A-bis-dianhydride, 3,4'-bisphenol A-bis-dianhydride, 3,3'-bisphenol A-bis-dianhydride or a combination including at least one of the foregoing.

[0133] Another aspect of the present invention includes wherein the imidic anhydride is present in an amount less than about 10%, preferably less than about 4%, based on the total weight of the imidic anhydride and the dianhydride.

[0134] Another aspect of the present invention includes wherein the product dianhydride contains trace amounts of imide.

[0135] Another aspect of the present invention includes wherein the dianhydride contains dimethyl sulfoxide and its derivatives as an impurity.

[0136] Another aspect of the present invention includes wherein the dianhydride contains acetic acid and its derivatives as an impurity.

[0137] Another aspect of the invention includes a method of making a polyimide composition comprising making a dianhydride according to any one or more of the preceding claims; polymerizing the dianhydride and a diamine to provide a polyetherimide composition.

[0138] The present disclosure is further illustrated by non-limiting examples.

[0139] II Dianhydride prepared by the method of the present invention

[0140] The present invention also includes the dianhydride prepared by the process of the present invention.

[0141] The present invention generally includes dianhydrides prepared by the process of the present invention wherein the dianhydride has an imidic anhydride content of from about 0.1% to about 10% based on the total weight of the aromatic dianhydride.

[0142] The present invention generally includes dianhydrides prepared by the process of the present invention, wherein the dianhydride contains trace amounts of imide.

[0143] The present invention generally includes dianhydrides prepared by the process of the present invention, wherein the dianhydride contains trace amounts of dimethyl sulfoxide and its derivatives as impurities.

[0144] The present invention generally includes dianhydrides prepared by the process of the present invention, wherein the dianhydride contains trace amounts of acetic acid and its derivatives as impurities.

[0145] Another aspect of the present invention includes a polyetherimide composition made by the process of the present invention.

[0146] The present disclosure is further illustrated by non-limiting examples.

[0147] Ill Other aspects and embodiments of the invention

[0148] Further included in this disclosure are the following specific aspects of the invention, which do not limit the claims.

[0149] Aspect 1: A method of making a dianhydride, the method comprising contacting an N-substituted imide with an organic sulfoxide and a carboxylic acid under conditions effective to provide a composition comprising the dianhydride.

[0150] Aspect 2: The method according to aspect 1, wherein the contacting of the N-substituted imide with the organic sulfoxide and the carboxylic acid is carried out in the presence of water.

[0151] Aspect 3: The method according to aspects 1 to 2, wherein the organic sulfoxide is substituted or unsubstituted dimethyl sulfoxide, dialkyl sulfoxide, diaryl sulfoxide, or a combination comprising at least one of the foregoing.

[0152] Aspect 4: The method according to aspects 1 to 2, wherein the carboxylic acid is substituted or unsubstituted acetic acid, aryl carboxylic acid, or a combination comprising at least one of the foregoing.

[0153] Aspect 5: The method according to aspects 1 to 4, wherein the mass ratio of the organic sulfoxide to the N-substituted imide is from about 1:1 to about 10:1.

[0154] Aspect 6: The method according to aspects 1 to 5, wherein the mass ratio of the carboxylic acid to the N-substituted imide is from about 1:1 to about 10:1.

[0155] Aspect 7: The method according to aspects 1 to 6, wherein the mass ratio of water to N-substituted imide is from about 2:1 to about 20:1.

[0156] Aspect 8: The method according to any one or more of the preceding aspects, wherein the N-substituted imide is contacted with the organic sulfoxide and the carboxylic acid in an aqueous medium at a temperature of about 150°C to about 230°C.

[0157] Aspect 9: The method according to any one or more of the preceding aspects, wherein the N-substituted imide is contacted with the organic sulfoxide and the carboxylic acid at a pressure of about 150 psi to about 250 psi.

[0158] Aspect 10: The method according to any one or more of the preceding aspects, wherein the reaction mixture precipitates in water or precipitates itself upon cooling.

[0159] Aspect 11: The method according to any one or more of the preceding aspects, wherein heating precipitation with a tetraacid provides a composition comprising a dianhydride.

[0160] Aspect 12: The method according to any one or more of the preceding aspects, wherein heating the reaction mixture with the tetraacid provides a composition comprising a dianhydride.

[0161] Aspect 13: The method according to any one or more of the preceding aspects, wherein the reaction mixture is heated with the tetraacid at a temperature of about 140°C to about 220°C.

[0162] Aspect 14: The method according to any one or more of the preceding aspects, wherein the reaction mixture is heated with the tetraacid at a pressure of about 200 mm Hg or less.

[0163] Aspect 15: The method according to any one or more of the preceding aspects, wherein the N-substituted imide has the formula

[0164]

[0165] The tetraacid has the formula

[0166]

[0167] The triacid has the formula

[0168]

[0169] The imide diacid has the formula

[0170]

[0171] The dianhydride has the formula

[0172]

[0173] In the above formula, R is an aryl group, C 1-5 Alkyl, preferably methyl; and A is -O-, or a group of formula -OEO-, wherein E has the formula

[0174]

[0175] Where R a and R b Each independently is a halogen atom or a monovalent C 1-6 alkyl groups, and may be the same or different; m and n are each an independent integer from 0 to 4; c is 0 to 4, specifically 0 or 1; and Z a is a bridging group connecting two aromatic groups, wherein the connection point between the bridging group and each C6 arylene group is located at the ortho, meta or para position (especially the para position) of each other on the C6 arylene group. a It can be a single bond, -O-, -S-, -S(O)-, -S(O)2-, -C(O)- or C 1-18 Organic bridging group. 1-18 The organic bridging group may be cyclic or acyclic, aromatic or non-aromatic, and may also include heteroatoms such as halogens, oxygen, nitrogen, sulfur, silicon or phosphorus. 1-18 The organic group may be arranged so that the C6 arylene groups attached thereto are each attached to a common alkylene carbon or to a C 1-18 The organic bridging group has different carbon atoms. Specific examples of group E are divalent groups of the formula

[0176]

[0177] Where L is a single bond, -O-, -S-, -C(O)-, -SO2-, -SO-, -C y H 2y - and its halogenated derivatives, wherein y is an integer from 1 to 5.

[0178] Aspect 16: The method according to aspect 15, wherein E is a 2,2(4-phenylene)isopropylidene group of the formula

[0179]

[0180] Aspect 17: The method according to aspect 15, wherein E is also 4-phenylene-1,1'-biphenyl of the following formula

[0181]

[0182] Aspect 18: A method of making a polyetherimide composition, comprising making a dianhydride according to any one or more of the methods of the preceding aspects; polymerizing the dianhydride and a diamine to provide a polyimide composition.

[0183] Aspect 19: A polyetherimide composition produced by the method according to aspect 18.

[0184] The compositions, methods and articles may alternatively include, consist of or consist essentially of any suitable material or component disclosed herein. The compositions, methods and articles may additionally or alternatively be formulated to be free of or essentially free of any material (or species), step or component that is not necessary to achieve the function or purpose of the compositions, methods and articles.

[0185] Example

[0186] Example 1: Synthesis of starting material imide

[0187] This example establishes a method for preparing the starting material imide using a previously established method.

[0188] Bisphenol A diimide (1):

[0189] Bisphenol A diimide was prepared based on the procedure described in U.S. Pat. No. 3,879,428. A 250 ml three-necked round bottom flask containing a magnetic stir bar was equipped with a thermocouple, a nitrogen inlet and a nitrogen outlet and a bubbler through a Dean-Stark separator. NaOH (1.6 g, 0.04 mol, 2.00 equiv) and water (1.6 ml) were added to the flask. The flask was placed in a heating mantle and stirred at room temperature until a solution was formed. Bisphenol A (4.566 g, 0.02 mol, 1.00 equiv), toluene (50 ml) and DMSO (30 ml) were added to the solution. The temperature of the heating mantle was slowly raised to 85°C and stirring was continued while distilling an azeotropic mixture of toluene and water. The distillation was continued for 3 hours while removing all toluene and water from the reaction mixture. The temperature of the system was slowly raised to 160°C and heated for another hour. To the mixture was added rV-methyl-4-nitrophthalimide (8.6587 g, 0.042 mole, 2.10 equivalents) as a solid and continued to heat for another 4 hours. HPLC analysis of the reaction mixture showed that most of the starting material N-methylphthalimide was consumed. The reaction flask was cooled to 70°C and filtered through a 90 mm filter paper using a suction filter setting to remove salts. The filtrate dark solution was slowly poured into 200 ml of water while stirring with a spatula to precipitate the product bisphenol A diimide. The slurry of the product in water was filtered through a 90 mm wet reinforced filter paper with a suction device. The precipitate was washed twice with 50 ml of water and dried overnight under vacuum at 100°C to obtain 8.7 g of product. The dark color of the product was removed by dissolving in dichloromethane and filtering through a silica plug.

[0190] Example 2: Synthesis of Dianhydride from Imide Starting Material

[0191] This example establishes that it is possible to prepare dianhydrides in high yield from the starting imide if the imide is reacted in an aqueous medium with acetic acid and dimethyl sulfoxide at elevated temperature and pressure, and the resulting tetraacid is then cyclized.

[0192] In an autoclave reactor equipped with a magnetic stir bar, bisphenol A diimide (4.372 g, 0.008 mole, 1.00 equivalent), dimethyl sulfoxide (9.37 g, 0.12 mole, 15.00 equivalent), acetic acid (9.6 g, 0.16 mole, 20.00 equivalent) and 15 ml of water were placed. The reactor was heated at 190° C. and 200 psi pressure while stirring for 6 hours. The reactor was cooled to room temperature. LCMS of the reaction mixture showed that the starting imide (1) was completely converted to the tetraacid, leaving behind traces of the starting material and partial hydrolysis products.

[0193] The reaction mixture was diluted with water (30 ml) to precipitate the resulting tetraacid. The aqueous slurry was centrifuged to afford a solid which was dried in vacuo at room temperature.

[0194] The solid tetraacid (2.0 g) was purged with nitrogen, heated to 200° C. under vacuum for 2 hours, and cooled to room temperature. LCMS analysis of the resulting solid showed the formation of a dianhydride of formula (11),

[0195]

[0196] Example 3: Preparation of Dianhydride in the Absence of Acetic Acid

[0197] This example establishes that if acetic acid is not present in the process described in Example 2, the synthesis of dianhydrides from diimides is either difficult or impossible, or the yields are very low.

[0198] In an autoclave reactor equipped with a magnetic stir bar, bisphenol A diimide (4.372 g, 0.008 mole, 1.00 equivalent), dimethyl sulfoxide (9.37 g, 0.12 mole, 15.00 equivalent) and 13 ml of water were placed. The reactor was heated at 190°C and 200 psi while stirring for 6 hours. The reactor was cooled to room temperature. LCMS of the reaction mixture showed no obvious conversion of the starting material.

[0199] Example 4: Preparation of Dianhydride in the Absence of Dimethyl Sulfoxide

[0200] This example establishes that, if dimethyl sulfoxide is not present in the process described in Example 2, the synthesis of the dianhydride from the diimide is either difficult or impossible, or the yield is very low.

[0201] In an autoclave reactor equipped with a magnetic stirrer, bisphenol A diimide (4.372 g, 0.008 mole, 1.00 equivalent), acetic acid (9.6 g, 0.16 mole, 20.00 equivalent) and 13 ml of water were placed. The reactor was heated at 190°C and 200 psi while stirring for 6 hours. The reactor was cooled to room temperature. LCMS of the reaction mixture showed no obvious conversion of the starting material.

[0202] Example 5: Preparation of Dianhydride in the Absence of Water

[0203] This example establishes that if water is not present in the process described in Example 2, the synthesis of dianhydrides from diimides is either difficult or impossible, or the yields are very low.

[0204] In an autoclave reactor equipped with a magnetic stirrer, bisphenol A diimide (4.372 g, 0.008 mole, 1.00 equivalent), dimethyl sulfoxide (9.37 g, 0.12 mole, 15.00 equivalent) and acetic acid (9.6 g, 0.16 mole, 20.00 equivalent) were placed. The reactor was heated at 190°C and 200 psi while stirring for 6 hours. The reactor was cooled to room temperature. LCMS of the reaction mixture showed no obvious conversion of the starting material.

[0205] Example 6: Synthesis of Dianhydride from N-Methylnitrophthalimide and Biphenol

[0206] A 250 ml three-necked round bottom flask containing a magnetic stirring bar was equipped with a thermocouple, a nitrogen inlet and outlet, and a bubbler through a Dean-Stark separator. Biphenol (3.72 g, 0.02 mole, 1.00 equivalent) and DMSO (50 ml) were added to the flask. Sodium hydroxide (1.76 g, 0.042 mol, 2.10 equivalent) as a 50% aqueous solution was added to this stirred solution. The reaction flask was heated to 90° C. in an oil bath for 2 hours. 20 ml of toluene was added to the mixture, and water-toluene was azeotroped into the Dean-Stark separator. N-methyl-4-nitrophthalimide (8.658 g, 0.042 mole, 2.10 equivalent) was added to the stirred dried reaction mixture at 100° C., and stirring was continued for 2 hours. LCMS analysis of the reaction mixture showed that most of the starting material was consumed, and the formation of biphenol diimide was the main product. The reaction mixture was poured into a 5% acetic acid solution in 200 ml of water. The precipitate was stirred for 15 minutes and the solid imide (9.2 g, 91%) was recovered by filtration.

[0207] The solid imide (1.0 g) was transferred to a 50 ml autoclave reactor with a magnetic stir bar. DMSO (2 ml), acetic acid (2 ml) and water (8 ml) were added. The reactor was sealed and heated overnight at 190° C. and 200 psi pressure while stirring. The reactor was cooled to room temperature. LCMS of the reaction mixture showed the only conversion of the imide to tetraacid, leaving behind traces of starting material and partial hydrolysis products.

[0208] The reaction mixture was diluted with water (10 ml) to precipitate the resulting tetraacid. The aqueous slurry was centrifuged to obtain a solid which was dried in vacuo at room temperature.

[0209] The solid tetraacid (1.0 g) was purged with nitrogen, heated to 200° C. under vacuum for 2 hours, and cooled to room temperature. LCMS analysis of the resulting solid (0.8 g) showed the formation of the dianhydride of formula (12),

[0210]

[0211] Example 7: Synthesis of Dianhydride from N-Methylnitrophthalimide and Hydroquinone

[0212] A 250 ml three-necked round bottom flask containing a magnetic stirring bar was equipped with a thermocouple, nitrogen inlet and outlet and a bubbler through a Dean-Stark separator. Hydroquinone (0.55 g, 0.005 mole, 1.00 equiv) and DMSO (10 ml) were added to the flask. Sodium hydroxide (0.42 g, 0.0105 mol, 2.1 equiv) was added as a 50% aqueous solution to this stirring solution. The reaction flask was heated to 90°C in an oil bath until the salt formation was complete. 20 ml of toluene was added to the mixture and the water toluene was azeotroped into the Dean-Stark separator. N-methyl-4-nitrophthalimide (2.164 g, 0.0105 mole, 2.10 equiv) was added to the dried reaction mixture stirred at 100°C and stirring was continued until the reaction was complete. Once complete, the DMSO solution of the imide reaction mixture was poured into a 5% acetic acid solution to precipitate the imide as a solid.

[0213] The obtained imide solid is transferred to a 50 ml autoclave reactor with a magnetic stirring bar. DMSO (5 ml), acetic acid (5 ml) and water (15 ml) are added to the solution. The reactor is sealed and heated at 190 ° C and 200 psi pressure while stirring. Once completed, the reactor is cooled to room temperature. The reaction mixture is diluted with water (30 ml) to precipitate the obtained tetra acid. The aqueous slurry is centrifuged to obtain a solid that is vacuum dried at room temperature.

[0214] The solid tetraacid is purged with nitrogen and heated to 200°C under vacuum to give the dianhydride of formula (13),

[0215]

[0216] Example 8: Synthesis of Dianhydride from N-Methylnitrophthalimide and Bisphenol A

[0217] A 250 ml three-necked round bottom flask containing a magnetic stirring bar was equipped with a thermocouple, a nitrogen inlet and outlet and a bubbler through a Dean-Stark separator. Bisphenol A (2.164 g, 0.005 mole, 1.00 equiv) and DMSO (10 ml) were added to the flask. Sodium hydroxide (0.42 g, 0.0105 mol, 2.1 equiv) was added as a 50% aqueous solution to this stirred solution. The reaction flask was heated to 90°C in an oil bath until the salt formation was complete. 20 ml of toluene was added to the mixture and the water toluene was azeotroped into the Dean-Stark separator. N-methyl-4-nitrophthalimide (2.164 g, 0.0105 mole, 2.10 equiv) was added to the dried reaction mixture stirred at 100°C and stirring was continued until the reaction was complete. Once complete, the DMSO solution of the imide reaction mixture was poured into a 5% acetic acid solution to precipitate the imide as a solid.

[0218] The obtained imide solid is transferred to a 50 ml autoclave reactor with a magnetic stirring bar. DMSO (5 ml), acetic acid (5 g) and water (15 ml) are added to the solution. The reactor is sealed and heated at 190 ° C and 200 psi pressure while stirring. Once completed, the reactor is cooled to room temperature. The reaction mixture is diluted with water (30 ml) to precipitate the obtained tetraacid. The aqueous slurry is centrifuged to obtain a solid that is dried under vacuum at room temperature.

[0219] The solid tetraacid is purged with nitrogen and heated to 200°C under vacuum to give the dianhydride of formula (11),

[0220]

[0221] Example 9: Synthesis of Dianhydride from N-Methylnitrophthalimide and 4,4'-Dihydroxydiphenylsulfone

[0222] A 250 ml three-necked round bottom flask containing a magnetic stirring bar was equipped with a thermocouple, a nitrogen inlet and outlet, and a bubbler through a Dean-Stark separator. 4,4'-dihydroxydiphenyl sulfone (1.251 g, 0.005 mole, 1.00 equiv) and DMSO (50 ml) were added to the flask. Sodium hydroxide (0.440 g, 0.0105 mol, 2.10 equiv) was added as a 50% aqueous solution to this stirred solution. The reaction flask was heated to 90°C in an oil bath until the salt formation was complete. 20 ml of toluene was added to the mixture, and the water toluene was azeotroped into the Dean-Stark separator. N-methyl-4-nitrophthalimide (2.165 g, 0.0105 mole, 2.10 equiv) was added to the dried reaction mixture stirred at 100°C, and stirring was continued until the reaction was complete. Once complete, the DMSO solution of the imide reaction mixture was poured into a 5% acetic acid solution to precipitate the imide as a solid.

[0223] The obtained imide solid is transferred to a 50 ml autoclave reactor with a magnetic stirring bar. DMSO (5 ml), acetic acid (5 g) and water (15 ml) are added to the solution. The reactor is sealed and heated at 190 ° C and 200 psi pressure while stirring. Once completed, the reactor is cooled to room temperature. The reaction mixture is diluted with water (30 ml) to precipitate the obtained tetraacid. The aqueous slurry is centrifuged to obtain a solid that is dried under vacuum at room temperature.

[0224] The solid tetraacid is purged with nitrogen and heated to 200°C under vacuum to give the dianhydride of formula (14),

[0225]

[0226] Example 10: Synthesis of Dianhydride from N-Methylnitrophthalimide and Resorcinol

[0227] A 250 ml three-necked round bottom flask containing a magnetic stirring bar was equipped with a thermocouple, a nitrogen inlet and outlet and a bubbler through a Dean-Stark separator. Resorcinol (0.550 g, 0.005 mole, 1.00 equiv) and DMSO (50 ml) were added to the flask. Sodium hydroxide (0.420 g, 0.0105 mol, 2.10 equiv) was added as a 50% aqueous solution to this stirred solution. The reaction flask was heated to 90° C. in an oil bath until the salt formation was complete. 20 ml of toluene was added to the mixture and the water toluene was azeotroped into the Dean-Stark separator. N-methyl-4-nitrophthalimide (2.165 g, 0.105 mole, 2.10 equiv) was added to the dried reaction mixture stirred at 100° C. and stirring was continued until the reaction was complete. Once complete, the DMSO solution of the imide reaction mixture was poured into a 5% acetic acid solution to precipitate the imide as a solid.

[0228] The obtained imide solid is transferred to a 50 ml autoclave reactor with a magnetic stirring bar. DMSO (5 ml), acetic acid (5 g) and water (15 ml) are added to the solution. The reactor is sealed and heated at 190 ° C and 200 psi pressure while stirring. Once completed, the reactor is cooled to room temperature. The reaction mixture is diluted with water (30 ml) to precipitate the obtained tetraacid. The aqueous slurry is centrifuged to obtain a solid that is dried under vacuum at room temperature.

[0229] The solid tetraacid is purged with nitrogen and heated to 200°C under vacuum to give the dianhydride of formula (15),

[0230]

[0231] Example 11: Synthesis of Dianhydride from N-Methylnitrophthalimide and Bisphenol A

[0232] This example establishes a method for preparing dianhydride from nitrophthalimide and bisphenol A without isolating the imide.

[0233] A 250 ml three-necked round bottom flask containing a magnetic stirring bar was equipped with a thermocouple, a nitrogen inlet and outlet and a bubbler through a Dean-Stark separator. Bisphenol A (2.164 g, 0.005 mole, 1.00 equiv) and DMSO (10 ml) were added to the flask. Sodium hydroxide (0.42 g, 0.0105 mol, 2.1 equiv) was added as a 50% aqueous solution to this stirred solution. The reaction flask was heated to 90°C in an oil bath until the salt formation was complete. 20 ml of toluene was added to the mixture and the water toluene was azeotroped into the Dean-Stark separator. N-methyl-4-nitrophthalimide (2.164 g, 0.0105 mole, 2.10 equiv) was added to the dried reaction mixture stirred at 100°C and stirring was continued until the reaction was complete.

[0234] Once completed, the DMSO solution of the imide reaction mixture was transferred to a 50 ml autoclave reactor with a magnetic stirring bar. Acetic acid (10 g) and water (20 ml) were added to the solution. The reactor was sealed and heated at 190 ° C and 200 psi pressure while stirring. Once completed, the reactor was cooled to room temperature. The reaction mixture was diluted with water (30 ml) to precipitate the resulting tetraacid. The aqueous slurry was centrifuged to obtain a solid that was dried under vacuum at room temperature.

[0235] The solid tetraacid is purged with nitrogen and heated to 200°C under vacuum to give the dianhydride of formula (11),

[0236]

[0237] References

[0238] WO 2019 / 245898 A1

[0239] WO 2017 / 172593 A1

[0240] WO 2019 / 236536 A1

[0241] WO 2019 / 222077 A1

[0242] WO 2017 / 189293 A1

[0243] WO 2019 / 217257 A1

[0244] US 4,329,496

[0245] US 6,008,374

[0246] US 5,359,084

[0247] US 3,879,428

[0248] US 4,017,511

[0249] US 5,536,846

[0250] US 3,957,862

[0251] US 4,263,209

[0252] US 4,571,425

[0253] US 4,318,857

[0254] 7,495,113 / B2

[0255] All publications, including patent documents and scientific articles and bibliographies and appendices, mentioned in this application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication was individually incorporated by reference.

[0256] All headings and titles are for the convenience of the reader and should not be used to limit the meaning of the text that follows the heading unless otherwise specified.

Claims

1. A method for preparing a dianhydride, the method comprising reacting an imide with acetic acid and dimethyl sulfoxide in an aqueous medium under certain conditions to provide a reaction mixture, the method comprising: a) providing a tetraacid, a triacid and an imide diacid, wherein the reaction temperature is 160°C to 250°C, and the reaction pressure is 150 psig to 300 psig; b) precipitating the tetraacid, triacid and imidodiacid in water; c) removing the dimethyl sulfoxide, the acetic acid and other by-products by filtering the precipitate; and d) converting the tetraacid precipitate into the corresponding dianhydride; wherein the imide has the formula wherein the tetraacid has the formula, wherein the triacid has the formula, Wherein the diacid imine has the formula, wherein the dianhydride has the formula, Wherein in the above formula, A is -OEO-, Wherein the E group has the formula: Where R a and R b Each independently is a halogen atom or a monovalent C 1-6 an alkyl group, m and n are each independently an integer from 0 to 4, c is from 0 to 4, and Z a is a bridging group connecting two aromatic groups, the bridging group Z a is a single bond, -O-, -S-, -S(O)-, -S(O)2-, -C(O)- or C 1-18 Organic bridging group, R is the unit price C 1-13 Organic group.

2. The method according to claim 1, Wherein E is 2,2-(4-phenylene)isopropylidene.

3. The method according to claim 1, Wherein E is 4-phenylene-1,1'-biphenyl.

4. The method according to any one of claims 1 to 3, The initial mass ratio of acetic acid to imide is 1:1 to 50:1, or 1:1 to 20:1, or 1:1 to 10:

1.

5. The method according to any one of claims 1 to 3, The initial mass ratio of dimethyl sulfoxide to imide is 1:1 to 50:1, or 1:1 to 20:1, or 1:1 to 10:

1.

6. The method according to any one of claims 1 to 3, The initial mass ratio of water to imide is 1:1 to 100:1, or 2:1 to 50:1, or 2:1 to 20:

1.

7. The method according to claim 1, The reaction mixture further comprises the imide, acetic acid and dimethyl sulfoxide and reaction and decomposition products thereof.

8. The method according to claim 1, The precipitation is carried out by addition to water.

9. The method according to claim 1, Wherein the precipitation is carried out by cooling the reaction mixture to 5°C to 50°C.

10. The method according to claim 1, The ratio of the reaction mixture used for precipitation to water is 1:0 to 1:

10.

11. The method according to claim 1, wherein the precipitate is heated at 180° C. to 250° C. under a reduced pressure of less than 200 mm / Hg.

12. The method according to claim 1, wherein the reaction mixture is directly converted to the dianhydride by heating at 180°C to 250°C under reduced pressure of less than 200 mm Hg.

13. The method according to claim 1, The conversion rate of the imide to the dianhydride is at least 90%.

14. The method according to claim 1, The imide includes 4,4'-bisphenol A-bis-N-methylphthalimide, 3,4'-bisphenol A-bis-N-methylphthalimide, 3,3'-bisphenol A-bis-N-methylphthalimide or a combination comprising at least one of the foregoing substances; the imide also includes 4,4'-biphenol-N-methylphthalimide, 3,4'-biphenol-N-methylphthalimide, 3,3'-biphenol-N-methylphthalimide or a combination comprising at least one of the foregoing substances; the dianhydride includes 4,4'-bisphenol A-bis-dianhydride, 3,4'-bisphenol A-bis-dianhydride, 3,3'-bisphenol A-bis-dianhydride or a combination comprising at least one of the foregoing substances; the dianhydride also includes 4,4'-biphenol-dianhydride, 3,4'-biphenol-dianhydride, 3,3'-biphenol-dianhydride or a combination comprising at least one of the foregoing substances.

15. The method according to claim 1, The dianhydride contains imidic anhydride, wherein the imidic anhydride is present in an amount less than 10% based on the total weight of the imidic anhydride and the dianhydride.

16. The method according to claim 1, The product dianhydride contains trace amounts of imide.

17. The method according to claim 1, The dianhydride contains dimethyl sulfoxide as an impurity.

18. The method according to claim 1, The dianhydride contains the acetic acid as an impurity.

19. A method for making a polyetherimide composition, the method comprising: a) producing a dianhydride according to the process of any one of the preceding claims 1 to 18; b) polymerizing the dianhydride and diamine to provide a polyetherimide composition.

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