WO2024205665A1

WO2024205665A1 - Epoxy-based thermoset polymers using mixed aromatic amines

Info

Publication number: WO2024205665A1
Application number: PCT/US2023/082333
Authority: WO
Inventors: Ozcan Altintas; Justin P. ROMAIRE; Loan T. VO; Bharath Natarajan; Adam B. BURNS; August W. Bosse
Original assignee: ExxonMobil Technology and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 2023-03-31
Filing date: 2023-12-04
Publication date: 2024-10-03
Anticipated expiration: 2025-09-30

Abstract

A variety of methods and thermoset polymer products are disclosed, including a method comprising nitrating at least a portion of an aromatic feed to produce a mixture of isomers of nitrated aromatic compounds, hydrogenating at least a portion of the mixture of isomers of nitrated aromatic compounds to produce a mixture of isomers of aromatic amine monomers, and reacting the mixture of isomers of aromatic amines with an epoxy resin to produce at least a thermoset polymer. In one or more embodiments, the thermoset polymer product comprises first repeating units of an epoxy group and a first tertiary amine having a first isomeric position, second repeating units of the epoxy group and a second tertiary amine having a second isomeric position, third repeating units of the epoxy group and a third tertiary amine having a third isomeric position, wherein the first, second, and third isomeric positions are different.

Description

EPOXY-BASED THERMOSET POLYMERS USING MIXED AROMATIC AMINES FIELD

[0001] This application relates to processes and systems for producing novel epoxy-based thermoset polymers using mixed aromatic amines with various epoxy compounds.

BACKGROUND

[0002] Epoxy-based compounds have a wide range of applications including coatings, adhesives, composite materials (carbon fiber and fiberglass reinforcement for example), concrete and cementitious systems, use in electronics, electrical components (for chips on board for example), etc. For instance, polymer-matrix composites (PMCs) have emerged as an attractive class of materials for structural applications. PMCs can provide the same mechanical properties (e.g., modulus and strength) as incumbents materials (e.g., concrete, steel, and wood) with markedly reduced weight and improved resistance to corrosion and rotting. Further, fiber reinforced polymer matrix composites provide an excellent substitute for conventional, homogeneous materials such as metals and ceramics by providing improved mechanical properties and the ability to directionally tailor material properties. Epoxy resins are the archetypal matrix material for high- performance PMCs. They have played a very important role in PMCs because of their superior mechanical and adhesive properties. They have been used widely as a matrix to hold the filler phase in composite materials due to their high-end mechanical performance and excellent chemical resilience. However, the wide-spread displacement of incumbent materials by PMCs is hindered, in part, by their relatively high cost.

[0003] Amines are important curing agents for epoxy resins. They are classified into aliphatic and aromatic amines. Aliphatic amines are curing agents for epoxy resin able to cure at room temperature. However, they generate a large amount of heat and have a short pot life. They show resistance to alkalis, some inorganic acids, water, and certain solvents, but their resistance to many organic solvents is poor. Aliphatic amines are also skin irritants and could be toxic. While those that have high molecular weight and low vapor pressure are less toxic, they still require careful handling.

[0004] Aromatic amines, on the other hand, have weaker basicity than aliphatic amines and cure more slowly at room temperature due to steric hindrance by the aromatic ring as well as the orientation of the amine groups. However, aromatic amines provide excellent heat resistance and mechanical properties. In addition, thermoset resins derived from aromatic amines have high electrical resistivity and excellent chemical and solvent resistance, particularly against alkalis. One disadvantage of aromatic amines as a hardener is that they are often solid at room temperature, and thus they must be heated when combining with the epoxy component. This can also be problematic during resin transfer molding (RTM), a common PMC fabrication technique, where aromatic amines may recrystallize and precipitate out of solution.

SUMMARY

[0005] In some embodiments, a method includes nitrating at least a portion of an aromatic feed to produce a mixture of isomers of nitrated aromatic compounds, hydrogenating at least a portion of the mixture of isomers of nitrated aromatic compounds to produce a mixture of isomers of aromatic amine monomers, and reacting the mixture of isomers of aromatic amines with an epoxy resin to produce at least a thermoset polymer.

[0006] In one or more embodiments, a method comprises providing a mixture of isomers of aromatic amines and reacting the mixture of isomers of aromatic amines with at least an epoxy resin to produce at least a thermoset polymer. The thermoset polymer includes first repeating units of an epoxy group and a first tertiary amine having a first isomeric position, second repeating units of the epoxy group and a second tertiary amine having a second isomeric position, third repeating units of the epoxy group and a third tertiary amine having a third isomeric position, wherein the first, second, and third isomeric positions are different.

[0007] In other embodiments, the thermoset polymer product includes first repeating units of an epoxy group and a first tertiary amine having a first isomeric position, second repeating units of the epoxy group and a second tertiary amine having a second isomeric position, third repeating units of the epoxy group and a third tertiary amine having a third isomeric position, wherein the first, second, and third isomeric positions are different.

[0008] These and other features and attributes of the disclosed methods and compositions of the present disclosure and their advantageous applications and/or uses will be apparent from the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] To assist those of ordinary skill in the relevant art in making and using the subject matter hereof, reference is made to the appended drawings, wherein:

[0010] FIG. 1 is a schematic diagram of an embodiment of an integrated process for producing epoxy-based thermoset polymers from mixed aromatics with various epoxy resin compounds.

[0011] FIG. 2 is a thermogravimetric analysis for a first set of thermoset polymers.

[0012] FIG. 3 illustrates the differential scanning calorimetric thermogram of the first set of thermoset polymers.

[0013] FIG. 4 shows a time-temperature-transformation diagram for curing of a first set of epoxy resins and the prediction for one of the epoxy resins based on a simple weighted average model.

[0014] FIG. 5 shows the compressive mechanical properties of the first set of thermoset polymers. [0015] FIG. 6 shows a thermogravimetric analysis of a second set of thermoset polymers.

[0016] FIG. 7 illustrates the differential scanning calorimetric thermogram of the second set of thermoset polymers.

DETAILED DESCRIPTION

[0017] This application relates to processes and systems for producing novel epoxy-based thermoset polymers from an aromatic feed. For example, the aromatic feed may be processed to produce a mixture of isomers of aromatic amines that can be used as a curing agent for various epoxy compounds to thereby form the epoxy -based thermoset polymers.

[0018] There may be several potential advantages to the methods and systems disclosed herein, only some of which may be alluded to in the present disclosure. For instance, the use of mixtures of aromatic amines as precursors for resin curing agents simplifies the value chain by eliminating the need to isolate a particular aromatic compound prior to amine functionalization and/or the separation step to recover a particular isomer from the anteceding aminated aromatics stream. Therefore, a feed comprising a mixture of aromatic molecules comprising benzene, toluene, and xylene for instance, can be nitrated, and hydrogenated directly to form a mixture of aromatic amines (e.g., aromatic diamines) for instance. This mixture of aromatic amines is then mixed with an epoxy resin to function as a curing agent thereby forming a thermoset polymer. In some embodiments, curing profile (rate of viscosity increase, rate of heat release, pot life, and cure time) of the thermoset polymers can be tuned to suit the application via the composition of the aromatic amine mixture.

[0019] As discussed above aromatic amine intermediates are important in the production of many useful products. Advantageously, the embodiments disclosed herein provide processes and systems that functionalize components of an aromatic feed to provide mixtures of isomers of aromatic amines which when utilized as a curing agent to produce epoxy -based products yield products with improved physical properties. For example, mixtures of isomers of aromatic amines may be used as a curing agent for epoxy compounds to produce thermosets with improved and/or tunable mechanical properties.

[0020] Embodiments may include an integrated process for the production of a mixture of isomers of aromatic amines from an aromatic feed and processing the resultant mixture of isomers to form a curing agent. The process may include the following steps: (1) nitration of at least a portion of an aromatic feed to produce a mixture of nitrated aromatic compounds; (2) catalytic hydrogenation of the mixture of nitrated aromatic compounds to produce a curing agent, which is the mixture of isomers of aromatic amines corresponding to the mixture of nitrated aromatic compounds; and (3) reacting the mixture of isomers of aromatic amine with an epoxy resin to form novel thermoset polymers. The aromatic feed in Step (1) may be from any source which contains aromatic compounds which may include a standalone source or a process stream from a unit within a refinery such as an aromatic extraction unit, or within a chemical plant, for example. By way of example, Step (3) may include reacting the mixture of isomers with one or more epoxy resins to form novel epoxy-based thermoset polymers.

[0021] In Step (1), any suitable technique for nitration of aromatic compounds to nitrated aromatic compounds may be used. For example, the nitration method may be a heterolytic or radical nitration method which may be non-catalyzed proceeding by reaction of the nitrating compound with the aromatic compounds or may be catalyzed by any suitable nitration catalyst. The nitration reaction may proceed in a gas or liquid phase and may be carried out in any suitable reactor. An exemplary nitration method is the mixed acid approach whereby the nitrating compound comprises a mixture of sulfuric acid and nitric acid. Another nitration method may include utilizing nitrogen dioxide and a catalyst such as Ni(CH3COO)2x4H2O. Reaction 1, corresponding to Step (1), is a generalized nitration reaction whereby an aromatic compound (R) is reacted with a nitrating compound (NO2) to produce a nitrated aromatic compound (R-NO2).

Reaction 1 yields

R + NO₂ - > R - NO₂

[0022] The aromatic feed may include any of a variety of aromatic compounds, corresponding to (R) in Reaction 1, may be used in the nitration of Step (1). Suitable compounds may have at least 5 carbons, such as 1,3 -cyclopentadiene, up to steam cracked tar which may have 17 or more carbons. Alternatively, suitable aromatic compounds may have boiling points in the range of 40 °C to 300 °C at atmospheric pressure. Some specific examples of aromatic compounds may include, but are not limited to, single ring aromatics such as benzene, toluene, xylenes (orthoxylene, meta-xylene, para-xylene), mesitylene, ethylbenzene, cumene, 1, 2, 4, 5-tetram ethyl benzene, C1-C12 alkyl substituted benzene, biphenyl, C1-C12 alkyl substituted biphenyl, tetrahydronaphthalene, C1-C12 alkyl substituted tetrahydronaphthalene, and polyaromatic hydrocarbons such as naphthalene, acenaphthylene, biphenylene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzanthracene, chrysene, benzo[a]pyrene, and Cl -Cl 2 alkyl substituted compounds thereof. Although only some single ring aromatics and polyaromatics are specified herein, single ring aromatics and/or polyaromatic compounds may be used without deviating from the present disclosure.

[0023] The nitration of Step (1) may be carried out at any suitable nitration conditions, including temperature, pressure, and residence time. For example, the nitration of Step (1) may be carried out at any temperature of -50 °C or greater. In some embodiments, the temperature of the nitration step may be selected to be in a range of from -50 °C to 100 °C, or from -50 °C to 0 °C, or from 0 °C to 50 °C, or from 50 °C to 100 °C. In some embodiments, the nitration may be carried out at a pressure of 0.5 bar to 10 bar or, alternatively, 0.5 bar to 1 bar, or 1 bar to 10 bar. In some embodiments, the residence time in the nitration reactor (e.g., nitration reactor 102 in FIG. 1) may be 2 hours to 48 hours or greater, depending on the desired amount of nitration, for example. Alternatively, the residence time may be selected to be 2 hours to 4 hours, 4 hours to 10 hours, 6 hours to 8 hours, or 10 hours to 48 hours. The residence time may be selected to give any desired conversion of the aromatic compounds to nitrated aromatic compound such as from 1% conversion to 100% conversion, or 15% to 70% conversion, or 20% to 60% conversion, or 30% to 50% conversion. In embodiments where the nitrated aromatic compounds contain more than one nitro group, selectivity to single, double, triple, or any other number of nitro groups may be controlled, for example, by selecting reaction conditions that promote the desired amount of nitro groups in the nitrated aromatic compound.

[0024] In some embodiments, an aromatic feed may be from a solvent assisted tar conversion process, sometimes referred to as SATC. Pyrolysis tar is a form of tar produced by hydrocarbon pyrolysis. One form of pyrolysis tar, steam cracked tar (“SCT”), contains a plurality of component species including high molecular weight molecules such as asphaltenes that are generated during the pyrolysis process and typically boil above 560° F. These asphaltenes molecules have low H/C and high sulfur content which contributes to high viscosity and high density of SCT. Solvent Assisted Tar Conversion (SATC) is an SCT upgrading process that includes mixing SCT with a utility fluid and upgrading the mixture into less viscous and less dense products including a hydro processed tar and solvent. At least a portion of the solvent can be recovered and recycled to the process, and the utility fluid can comprise recycled solvent. The upgrading can include cracking and hydroprocessing, e.g., one or more of thermal cracking, hydrocracking, and hydrogenation. The process is typically carried out under pressure and weight hourly space velocity (“WHSV”) conditions that are selected to optimize one or more of SCT conversion, hydroprocessed tar yield/quality, and solvent yield/and quality. Operating temperature is also an important process parameter that can be adjusted to maintain the desired solvent quality. While the hydrogenation of aromatic molecules is favored when hydroprocessing at lower temperature (e.g., 300° C ), a lesser amount of cracking occurs. This will increase the partially and/or completely hydrogenated molecules in the product which will eventually be present in recycle solvent after distillation. The increase in number of hydrogenated molecules in recycle solvent decreases the solvency power of the recycle solvent, in turn, reduces the ability of the recycle solvent to dissolve tar components. Another feature of SATC is the recycling of a cut of self-generated product as solvent. The amount of solvent recycled for use as utility fluid is typically 20 wt. % to 60 wt. %, e.g., 40 wt. %. Solvent recovered from a SATC process typically has a desirably high solvency power, as indicated by the solvent's appreciable solubility blending number (SBN). If the SBN of the recovered solvent is less than 100, such as 80 or 90, the recycle solvent has a decreased ability to dissolve the tar and is therefore less desirable for use as utility fluid or utility fluid constituent.

[0025] In some embodiments, the aromatic feed to Step (1) may be from any source which contains aromatic compounds which may include a standalone source or a process stream from a unit within a refinery or chemical plant, for example. The aromatic feed may be from the overhead liquid distillate from the crude oil distillation unit or straight-run naphtha. Some aliphatic molecules may have to be removed from this stream. It may also be from tar material content such as an atmospheric column bottoms stream, sometimes referred to as main column bottoms. Another source of aromatic feed to Step (1) may be from a vacuum distillation tower bottom, sometimes referred to as a vac resid stream. For instance, the aromatic feed may be the product of an aromatic extraction unit in a refinery. In embodiments, aromatic feed may include one or more process streams such as reformate from a catalytic reformer, an aromatic extraction unit, a BTX (benzene, toluene, xylene) stream, a transalkylation unit, a bottoms stream from an atmospheric distillation column, a bottoms stream from a fluidized catalytic cracked stream, or a SATC stream from a SATC unit, for example.

[0026] Regardless of the source of the aromatics, isomers do not need to be separated into one or more embodiments of the present disclosure saving time and energy. For instance, o-xylene, m- xylene, and p-xylene do not need to be separated before Step (1). Further, the nitrated and hydrogenated isomers of xylene yielding 3,4-diamino-ortho-xylene, 3,5-diamino-ortho-xylene, 3,6-diamino-ortho-xylene, 4,5-diamino-ortho-xylene, 4,6-diamino-ortho-xylene, and 5,6-diamino- ortho-xylene do not need to be separated at the end of Step (2). Likewise, the various isomers of ortho-toluene diamine, meta-toluene diamine, and para-toluene diamine do not need to be separated at the end of Step (2) before being used as curing agent with an epoxy resin to form novel epoxy -based thermoset polymers in Step (3). In addition, the mixture of isomers allows for a better control of the curing reaction in Step (3) as compared to using one of the specific isomers. For instance, the mixture of ortho-xylene, meta-xylene, and para-xylene allows for a simpler and more cost-effective process by eliminating the separation step before the functionalization reaction as compared to using one of the specific isomers.

[0027] In Step (2), any suitable technique for hydrogenation of the nitrated aromatic compounds to form a mixture of isomers of aromatic amines may be used. Some suitable hydrogenation techniques may include, but are not limited to, hydrogenation using H2 with palladium on carbon (Pd/C) catalyst, H2 and Raney nickel catalyst, iron (Fe) under acidic conditions such as in the presence of acetic acid, zinc (Zn) under acidic conditions such as in the presence of acetic acid, tin(II) chloride (SnCh) with alcohol reflux, sodium sulfide (Na2S) with alcohol reflux, lithium aluminum hydride (LiAIFU) in tetrahydrofuran (THF), or any other suitable hydrogenation technique. The hydrogenation reaction may proceed in a gas or liquid phase and may be carried out in any suitable reactor. Reaction 2, corresponding to Step (2), is a generalized hydration reaction whereby the nitrated aromatic compound (R-NO2) produced in Step (1) is hydrogenated with hydrogen (H2) to form the aromatic amine monomer (R-NH2) corresponding to the nitrated aromatic compound.

Reaction 2 yields

R - NO₂ + 3 H₂ - > R - NH₂ + 2 H₂O

[0028] The hydrogenation of Step (2) may be carried out at any suitable hydrogenation conditions, including temperature, pressure, and residence time. For example, the hydrogenation of Step (2) may be carried out at any temperature of -50 °C or greater. In some embodiments, the temperature of the hydrogenation step may be selected to be in a range of from -50 °C to 100 °C. Alternatively, the temperature of the hydrogenation step may be selected to be in a range of from -50 °C to 0 °C, from 0 °C to 50 °, or 50 °C to 100 °C. In some embodiments, the hydrogenation may be carried out at a pressure of 0.5 bar to 40 bar or, alternatively, 0.5 bar to 1 bar, 1 bar to 10 bar, or 10 bar to 40 bar. In some embodiments, the residence time in the hydrogenation reactor (e.g., hydrogenation reactor 104 on FIG. 1) may be 2 hours to 48 hours or greater, depending on the desired amount of hydrogenation, for example. Alternatively, the residence time may be selected to be 2 hours to 4 hours, 4 hours to 10 hours, 6 hours to 8 hours, or 10 hours to 48 hours. The residence time may be selected to give any desired conversion of the nitrated aromatic compounds to the corresponding aromatic amine such as from 1 % conversion to 100 % conversion, or 15 % to 70 % conversion, or 20 % to 60 % conversion, or 30 % to 50 % conversion. In some embodiments, the aromatic amine produced from step (2) may be desired to be stored for a period of time. Aromatic amine may be preserved by treatment with concentrated HC1 such that the aromatic amine form the corresponding ammonium salts which may be more stable.

[0029] The mixture may include two or more different isomers of aromatic amines. For example, the mixture may include one or more of ortho, para, and meta isomers of a di substituted aromatic amine. In some embodiments, the mixture may include a first mixture of isomers of an aromatic amine and a second mixture of isomers of another aromatic amine with a different element composition. In some embodiments, the mixture of aromatic amines may include a third mixture of isomers of a distinct aromatic amine. Additional aromatic amines may also be present in the mixture, including a fourth aromatic amine, a fifth aromatic amine, and/or additional isomers. These aromatic amines, including the first, second, third, fourth, and/or fifth mixture of isomers may include any of the preceding isomers of aromatic amines. For instance, the isomers of phenylenediamine may include ortho-phenylenediamine, meta-phenylenediamine, and paraphenylenediamine. The isomers of toluene diamine may include 2,3 -diaminotoluene, 2,4- diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 3,4-diaminotoluene, and 3,5- diaminotoluene. The isomers of ortho-xylene diamine may include 3,4-diamino-ortho-xylene, 3,5- diamino-ortho-xylene, 3,6-diamino-ortho-xylene, 4,5-diamino-ortho-xylene, and 4,6-diamino- ortho-xylene. The isomers of meta-xylene diamine may include 2,4-diamino-meta-xylene, 2,5- diamino-meta-xylene, 2,6-diamino-meta-xylene, and 2,3-diamino-meta-xylene. The isomers of para-xylene diamine may include 2,3-diamino-para-xylene, 2,5-diamino-para-xylene, and 2,6- diamino-para-xylene.

[0030] The first isomer and the second isomer in the mixture of isomers may be present in any suitable proportion. For example, the first isomer may be present in an amount of about 1 wt% to about 99 wt%, or about 5 wt% to about 95%, or about 10 wt% to about 90 wt%, or about 20 wt% to about 80 wt%, or about 10 wt% to about 50 wt%, or about 20 wt% to about 40 wt%, or about 50 wt% to about 90 wt%. By way of further example, the second isomer may be present in an amount of about 1 wt% to about 99 wt%, or about 5 wt% to about 95 wt%, or about 10 wt% to about 90 wt%, or about 20 wt% to about 80 wt%, or about 10 wt% to about 50 wt%, or about 20 wt% to about 40 wt%, or about 50 wt% to about 90 wt%. Where present, the third isomer (or additional isomers) may be present in any suitable amount. For example, the third isomer may be present in an amount of about 1 wt% to about 99 wt%, or about 5 wt% to about 95 wt%, or about 10 wt% to about 90 wt%, or about 20 wt% to about 80 wt%, or about 10 wt% to about 50 wt%, or about 20 wt% to about 40 wt%, or about 50 wt% to about 90 wt%.

[0031] Step (3) of the present disclosure may include any technique for polymerizing at least a portion of an epoxy resin with at least a portion of the mixtures of isomers of aromatic amines as a curing agent to produce an epoxy-based thermoset polymer. The polymerization may be any number of processes which take as input the mixture of isomers of aromatic amines produced in Step (2) as the curing agent to cure the epoxy resin to produce isomers of epoxy-based thermoset polymers in Step (3). Bifunctional isomeric mixtures of aromatic amine which comprise two amine groups per molecule may be used to produce thermoplastics through step growth polymerization, for example. Trifunctional or higher functionality mixture of isomers of aromatic amine may be used to produce polymers whereby crosslinks between the oligomers are formed. Polymerization of epoxy resin by the isomeric mixture of aromatic amine from Step (2) may be a versatile approach to synthesize novel high-performance thermosets with improved properties.

[0032] Because the curing agent used in Step (3) is a mixture of isomers, the resultant thermoset polymer should have repeating units with tertiary amines in different isomeric positions in one or more embodiments. In some embodiments, there may be tertiary amines in at least three different isomeric positions, wherein tertiary amines may be present in an amount of about 5 wt% to about 95 wt%, or about 10 wt% to about 90 wt%, or about 20 wt% to about 80 wt%, or about 10 wt% to about 50 wt%, or about 20 wt% to about 40 wt%, or about 50 wt% to about 90 wt%. For example, the thermoset polymer may include: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isometric position; and third repeating units of the epoxy group and a third tertiary amine having a third isometric position; wherein the first, second, and third isometric positions are different. The first, second, and third repeating units may each be present in the thermoset polymer in any suitable amount. For example, the first, second, and third repeating units may each be present in an amount individually selected from at 5 wt% or more. In some embodiments, the first, second, and third repeating units may each be present in an amount individually selected from about 5 wt% to about 95 wt%, from about 10 wt% to about 85 wt%, from about 10 wt% to about 75 wt%, about 10 wt% to about 50 wt%, about 10 wt% to about 20 wt%, about 20 wt% to about 50 wt%, or about 30 wt% to about 70 wt%.

[0033] The thermoset polymer of Step (3) may be any compound characterized by the presence of an oxirane or epoxy ring. Some epoxy resins may have poor mechanical, chemical, and heat resistance properties. However, good properties are obtained by reacting the linear epoxy resin with suitable curatives to form three-dimensional crosslinked thermoset structures. This process is commonly referred to as curing. Curing epoxy resins is an exothermic reaction. Epoxy resins may be crosslinked or cured either with themselves through catalytic homopolymerization, or with a wide range of co-reactants, or curing agents or hardeners, including polyfunctional amines, acids (and acid anhydrides), phenols, alcohols, and thiols. Reaction of epoxy resins with a curing agent forms epoxy-based thermoset polymers, often with favorable mechanical properties and high thermal and chemical resistance. Epoxy-based thermoset polymers have a wide range of applications, including paints and coatings, adhesive composites (e.g., for construction and repair, wind turbines, or aerospace), use in electronics (e.g. for chips on board), LEDs, high-tension electrical insulators, and fiber-reinforced plastic materials, for example.

[0034] One of the most well-known epoxy compounds is diglycidyl ether of bisphenol A (DGEBA):

Structure 1 [0035] However, alternative epoxies, such as chemical structures 2-9 shown below, can be used with mixed aromatic amines to formulate thermosets with various curing profiles and with various thermal and mechanical properties:

Structure 5

Structure 9

[0036] The above epoxy resin examples will react with a curing agent in Step (3). Polyfunctional amines form an important class of epoxy curing agent. Each N-H bond in an amine group undergoes an addition reaction with the epoxide group to form a hydroxyl group and a substituted amine. A primary amine can react with two epoxides, while a secondary amine can react with one. Thus, a three-dimensional, crosslinked network can form, if the average number of N-H groups per molecule in the curing agent is greater than two. The reaction kinetics depend on the nature of the amine (kinetic studies have shown the reactivity of the primary amine to be approximately double that of the secondary amine) as well as the steric environment, with more sterically hindered amines reacting more slowing. Therefore, the mixed aromatic amines disclosed can be formulated to tune the curing profile (rate of viscosity increase, rate of heat release, pot life, and cure time).

[0037] Several curing agents for epoxy -based resins can be generated from other low-cost aromatic hydrocarbon feeds such as toluene, other methylbenzenes (e.g., mesitylene and durenes), tetrahydronaphthalene, 1 -methyl naphthalenes, 2-methyl naphthalene, other methylated naphthalenes, anthracene, phenanthrene, pyrene, benzene, toluene, ethylbenzene, and xylene or BTEX, AR-200, and heavy aromatics such as Vac-resid, SATC, and MCB to generate curing agents. Table 1 below shows examples of mixtures of isomers of aromatic amines that can be produced in Step 2 together with the corresponding aromatic feedstock to Step 1.

Table 1

[0038] For instance, in the first row of Table 1, mixture of isomers of phenylenediamine are obtained from benzene after Step (1) and Step (2) described above. In row 2, mixture of isomers of toluene diamines are obtained from toluene after Step (1) and Step (2) with toluene-2,4-diamine, toluene-2,5-diamine, and toluene-2,6-diamine. In row 3, mixture of isomers of ortho-xylene diamine are obtained after Step (1) and Step (2) with 4,5-diamine-ortho-xylene, 3,5-diamine-ortho- xylene, 3,6-diamine-ortho-xylene, and 3,4-diamine-ortho-xylene. Likewise, for mixture of isomers of meta-xylene diamine in row 4 with 4,6-diamino-meta-xylene and 2,4-diamino-meta-xylene shown after Step (1) and Step (2). In row 5, mixture of isomers of para-xylene diamine are shown with 2,3-diamino-para-xylene, 2,6-diamino-para-xylene, and 2,5-diamino-para-xylene obtained after Step (1) and Step (2). In row 9, mixture of isomers of naphthalene diamine are produced from naphthalene after Step (1) and Step (2). In row 10, a mixture of isomers of methyl-naphthalene diamine are produced from methylnaphthalene after Step (1) and Step (2). The use of such feedstocks stands to lower the cost of epoxy resins for infrastructural applications.

[0039] In Step (3), mixture of isomers of monofunctional aromatic amines which comprise one amine group per molecule may be used to produce thermoplastics through step growth polymerization, for example. Trifunctional or higher functionality mixture of isomers of aromatic amines may be used to produce polymers whereby crosslinks between the oligomers in solution are formed. Polymerization of the mixture of isomers of aromatic amines from Step (2) may be a versatile approach to synthesize novel high-performance polymers with improved properties. The mixed aromatic amines may be copolymerized with aliphatic or aromatic acid chlorides using stepgrowth polymerization to obtain mixed polyamides. [0040] The following Reactions 3 to 12 illustrate various reaction schemes for producing mixtures of isomers of aromatic amines. Specifically, Reactions 3 to 12 illustrate various examples of mixture of isomers that can formed from example aromatic feedstocks to Step (1). For example, Reaction 3 below shows the nitration of ortho-xylene, corresponding to Step (1) above, to a mixture of nitrated ortho-xylene compounds and the subsequent hydrogenation, corresponding to Step (2) above, of the nitrated ortho-xylene compounds to a mixture of isomers of aromatic diamines. The molar fraction of each isomer is generally related to reaction kinetics and reaction conditions and may vary depending on the particular reaction conditions selected. For instance, when reaction temperature or pressure or concentration of one isomer changes, the composition of the products will change as well.

Reaction 3

[0041] For example, the 4,6-diamine-ortho-xylene may represent 30-50 % by mole of the isomers, 3,4-diamine-ortho-xylene may represent 30-40 % by mole, 3,6-diamine-ortho-xylene may represent 10-20 % by mole, and the 4,5-diamine-ortho-xylene may represent 5-15 % by mole of the isomers.

[0042] Reaction 4 below shows the nitration of meta-xylene, or m-xylene, corresponding to Step (1) above, to a mixture of nitrated m-xylene compounds and the subsequent hydrogenation, corresponding to Step (2) above, of the nitrated m-xylene compounds to a mixture of isomers of aromatic diamines. The molar fraction of each isomer is generally related to reaction kinetics and reaction conditions and may vary depending upon the particular reaction conditions selected.

Reaction 4

[0043] For instance, the 4,6-diamine-meta-xylene may represent 50-70 % by mole of the isomers and the 2,6-diamine-meta-xylene may represent 30-50 % by mole of the isomers.

[0044] Reaction 5 below shows the nitration of para-xylene, or p-xylene, corresponding to Step (1) above, to a mixture of nitrated p-xylene compounds and the subsequent hydrogenation, corresponding to Step (2) above, of the nitrated p-xylene compounds to a mixture of isomers of p- xylene diamine. The molar fraction of each isomer is generally related to reaction kinetics and reaction conditions selected.

Reaction 5

[0045] For instance, the 2,6-diamine-para-xylene may represent 50-60 % by mole of the isomers, the 2,5-diamine-para-xylene may represent 25-35 % by mole, and the 2,3-diamine-para-xylene may represent 10-20 % by mole of the isomers.

[0046] Reaction 6 below shows the nitration of tetrahydronaphthalene, corresponding to Step (1) above, to a mixture of nitrated tetrahydronaphthalene compounds and the subsequent hydrogenation, corresponding to Step (2) above, of the nitrated tetrahydronaphthalene compounds of a mixture of isomers tetrahydronaphthalene diamine. The molar fraction of each isomer is generally related to reaction kinetics and reaction conditions and may vary depending upon the particular reaction conditions selected.

Reaction 6

[0047] For instance, the 5,6,7,8-tetrahydronaphthalene-l,3-diamine may represent 30-50 % by mole of the isomers, the 5,6,7,8-tetrahydronaphthalene-l,2-diamine may represent 30-40 % by mole, the 5,6,7,8-tetrahydronaphthalene-l,4-diamine may represent 10-20 % by mole, and the 4,5,6,7-tetrahydronaphthalene-l,2-diamine may represent 5-15 % by mole of the isomers.

[0048] Reaction 7 below shows the nitration of a mixture of xylene isomers, corresponding to Step (1) above, to a mixture of nitrated xylene isomer compounds and the subsequent hydrogenation, corresponding to Step (2) above, of the mixture of nitrated xylene isomers into a mixture isomers of xylene diamine.

Reaction 7

[0049] The following Reactions 8-13 illustrate reaction schemes for production of various example thermoset polymers from by reacting a mixture of aromatic amines with an epoxy. For instance, Reaction 8 illustrates the reaction scheme whereby a mixture of phenylenediamine isomers reacts with diglycidyl ether of bisphenol A (DGEBA) to form a thermoset polymer:

Reaction 8

[0050] Novel epoxy-based thermoset materials may be prepared from mixtures of aromatic diamine prepared by functionalizing isomers of xylenes. For instance, 4,6-diamine-meta-xylene and 2,6-diamine-meta-xylene (the product mixture resulting from the nitration and hydrogenation of meta-xylene) react with DGEBA to form thermoset polymer P5 in Reaction 9:

Reaction 9

[0051] In Reaction 10, DGEBA may react with a mixture of isomers of diamine of para-xylene (2,3-diamine-para-xylene, 2,6-diamine-para-xylene, and 2,5-diamine-para-xylene) to form thermoset polymer P6: Reaction 10

PS

[0052] In Reaction 11, DGEBA may react with a mixture of isomers of diamine of ortho-xylene (3,5-diamine-ortho-xylene, 3,6-diamine-ortho-xylene, 4,5-diamine-ortho-xylene, and 3,4- diamine-ortho-xylene) to form thermoset polymer P7:

Reaction 11

[0053] DGEBA can also react with a mixture of diamine isomers of tetralin to form thermoset polymer P8 as illustrated in Reaction 12 below:

Reaction 12

[0054] In Reaction 13, DGEBA reacts with a mixture of isomers of diamine of ortho-, meta-, and para-xylene to form thermoset polymer P9:

Reaction 13

[0055] FIG. l is a schematic diagram of an embodiment of an integrated process 100 for producing novel epoxy-based thermoset polymers from various epoxy resins with a mixture of aromatic diamines as the curing agent. As illustrated, integrated process 100 may include a nitration reactor 102, a hydrogenation reactor 104, and production unit 106. Integrated process 100 may begin with feeding an aromatic feed 108 containing aromatic compound and a nitrating agent feed 110 containing a nitrating agent to nitration reactor 102. The nitration reactor 102 may contain reaction conditions such that at least a portion of the aromatic compound from aromatic feed 108 may be reacted with at least a portion of the nitrating agent from nitrating agent feed 110 to produce a mixture of nitrated aromatic compounds in accordance with Step (1) above. The nitrated aromatic compounds produced in nitration reactor 102 may be fed to hydrogenation reactor 104 as nitrated aromatic stream 112.

[0056] Aromatic feed 108 may be from any source which contains aromatic compounds which may include a standalone source or a process stream from a unit within a refinery or chemical plant, for example. For instance, the aromatic feed 108 may be the product of an aromatic extraction unit in a refinery. In embodiments, aromatic feed 108 may include one or more process streams such as reformate from a catalytic reformer, an aromatic extraction unit, a BTX (benzene, toluene, xylene) steam, a transalkylation unit, a bottoms stream from an atmospheric distillation column, a bottoms stream from an FCC (fluidized catalytic cracker) stream, or a stream from a SATC unit, for example. In embodiments, aromatic feed 108 may include any of the aromatic compounds disclosed herein. While aromatic feed 108 and nitrating agent feed 110 are shown being fed separately into nitration reactor 102, it should be understood that these streams may be combined and co-fed into nitration reactor 102, as desired for a particular application.

[0057] In hydrogenation reactor 104, at least a portion of the nitrated aromatic compounds in nitrated aromatic stream 112 may be hydrogenated to form the corresponding aromatic amine in accordance with Step (2) above. Hydrogen stream 114 comprising hydrogen gas may be introduced to hydrogenation reactor 104 as a hydrogen source in the hydrogenation reaction. Excess hydrogen may exit hydrogenation reactor 104 as recycle stream 116, for example. An aromatic amine stream 118 comprising the aromatic amine produced in hydration reactor 104 may be fed into production unit 106. In some embodiments, aromatic amine stream 118 may be sold and shipped to another location where a thermoset polymer is made.

[0058] In production unit 106, any of the previously discussed applications of the aromatic amine may be performed to produce a desired product corresponding to Step (3) above. Product steam 120 may exit production unit 106. Some exemplary production units may include polymerization units capable of polymerizing the epoxy resin with the mixture of isomers of aromatic diamines as curing agent into novel epoxy-based thermoset polymers. The use of such feedstocks stands to lower the cost of epoxy resins for infrastructural applications. EXAMPLES

[0059] To facilitate a better understanding of the present invention, the following examples of certain aspects of some embodiments are given. In no way should the following examples be read to limit, or define, the entire scope of the disclosure.

Example 1

[0060] For this example, various thermoset polymers were prepared, identified herein as Pl, P2, P3, and P4 respectively. In contrast, to the preceding description, thermoset polymers P1-P3 are comparative polymers that were not prepared from mixtures of isomers. Thermoset polymer P4 was prepared from a mixture of isomers of aromatic amines. After preparation, the thermoset polymers P1-P4 were tested to determine thermal stability, glass transition temperature, curing properties, and compressive mechanical properties.

[0061] Thermoset polymer Pl was prepared by reacting diglycidyl ether of bisphenol A (DGEBA) with ortho-phenylenediamine as shown below:

Reaction 14

[0062] Thermoset polymer P2 was prepared by reacting diglycidyl ether of bisphenol A (DGEBA) with meta-phenylenediamine as shown below:

Reaction 15

[0063] Thermoset polymer P3 was prepared by reacting diglycidyl ether of bisphenol A (DGEBA) reacts with para-phenylenediamine as shown below:

Reaction 16

[0064] Thermoset polymer P4 was prepared by reacting isomers of phenylenediamine in equal quantity with diglycidyl ether of bisphenol A (DGEBA) as shown in Reaction 17 reproduced below:

Reaction 17

[0065] Specifically, the isomers of phenylenediamine and DGEBA were mixed homogeneously in a DGEBA/N-H equivalent ratio of 1 to 1 by stir bar at 90 °C to melt the phenylenediamine and form a homogeneous mixture. The viscous liquid mixtures were poured into a mold and cured at 100 °C for 16 hours and then cured at 150 °C for 4 hours. In other embodiments, phenylenediamine and DGEBA may be mixed in different ratios.

[0066] The thermal stability of the thermoset polymers Pl, P2, P3, and P4 was analyzed by thermal gravimetric analysis (TGA) at a heating rate of 10 °C min'¹ from ambient temperature up to 800 °C under nitrogen. The mass loss profiles for the thermoset polymers Pl, P2, P3, and P4 are depicted in FIG. 2. The initial decomposition temperature can be considered as the temperature at which the weight loss is 5 wt% which begins at 370 °C, 380 °C, 355 °C, and 362 °C for Pl, P2, P3, and P4, respectively. The thermal degradation behavior is classified into one-step as revealed in FIG. 2 indicating that there is no significant difference for the comparative thermoset polymers Pl to P3 each formed from a single isomer and thermoset polymer P4 prepared from the mixture of isomers.

[0067] The glass transition temperature (T_g) is an important parameter for application of epoxy thermosets and was investigated by differential scanning calorimetry (DSC). FIG. 3 illustrates the DSC curves of the thermoset polymers Pl, P2, P3, and P4. Scans were performed at a rate of 10 °C min'¹ and the results from the second heating scan from ambient temperature to up to 250 °C were used to determine the T_g value of the thermoset polymers (FIG. 3). Thermoset polymers Pl, P2, P3, and P4 showed distinct T_g at 164 °C, 172 °C, 185 °C, and 172 °C, respectively. The high T_g values are due to the rigidity afforded by aromatic moieties in the polymer network.

[0068] Time-temperature-transformation (TTT) diagrams were constructed to study the curing behavior of thermoset polymers Pl, P2, P3, and P4, as shown in FIG. 4. TTT diagrams depict the time at which the resin vitrifies at a given curing temperature, dramatically slowing down the rate of cure. It can be seen from the TTT diagram that thermoset polymer P4, which comprises equimolar ratios of the three isomers of phenylenediamine, shows curing behavior quite similar to comparative thermoset polymer P2 issued from the curing of pure meta-phenylenediamine, which is the ubiquitous commercial aromatic curing agent for epoxy resin. The curing behavior of P4 shown to be intermediate between the pure isomers, Pl, P2, and P3. A simple composition weighed average of the cure times from the comparative thermoset polymers Pl, P2, and P3 adequately predicts the cure time for P4 (shown as the dotted line labeled “P4 model” in FIG. 4). Thus, these results demonstrate that mixtures of isomers of aromatic amines can be used to tune the curing characteristics of epoxy resins, in a predictable way, and without loss of performance, affording a new handle for epoxy resin formulation.

[0069] Compressive mechanical properties (compressive strength and elastic modulus) were measured on molded rods, between 12 and 16 mm long, and 8 mm in radius. The measurements were made at room temperature at a rate of 0.6 mm/min and repeated on at least 5 specimens for each sample. The average compressive modulus and strength with standard deviations for thermoset polymers issued from ortho-phenylenediamine (Pl) as curing agent, from meta- phenylenediamine (P2), from para-phenylenediamine (P3), and from a mixture of isomers of phenylenediamines in equal quantity (P4) are depicted in FIG. 5. The compressive mechanical properties of comparative thermoset polymers Pl, P2, and P3 issued from pure diamines as curing agent are comparable to each other (within standard deviation) with comparative thermoset polymer Pl having the highest average properties. The compressive mechanical properties of thermoset polymer P4 issued from the mixture of isomers of phenylenediamines were also comparable to comparative thermoset polymers Pl, P2, and P3, with the average properties closest to comparative thermoset polymer Pl issued from ortho-phenylenediamine as curing agent; again, demonstrating that the mixture of isomers of phenylenediamines as curing agent does not negatively affect the performance of the cured resin.

Example 2

[0070] For this example, additional thermoset polymers were prepared identified herein as P5, P6, P7, P8, and P9. These thermoset polymers were prepared from a mixture of isomers of aromatic amines. After preparation, the thermoset polymers P5-P9 were tested for thermal stability and glass transition temperature.

[0071] For instance, thermoset polymer P5 was prepared from the reaction of a mixture of isomers of meta-xylene diamine (4,6-diamine-meta-xylene and 2,6-diamine-meta-xylene) with DGEBA as shown in Reaction 18 reproduced below:

Reaction 18

[0072] Thermoset polymer P5 was prepared by mixing the mixture of isomers of meta-xylene diamine (4,6-diamine-meta-xylene and 2,6-diamine-meta-xylene) with DGEBA homogeneously in an epoxide/N-H equivalent ratio of 1/1 by stir bar at 60 °C at the melting temperature of DGEBA as the aromatic diamines have a lower melting point than DGEBA (they are liquid at room temperature). The resulting viscous liquid mixtures were poured into a mold and cured at 100 °C for 16 hours and subsequently cured at 150 °C for 4 hours.

[0073] Thermoset polymer P6 was prepared in the reaction conditions described above by mixing a mixture of isomers of para-xylene diamine (2,3-diamine-para-xylene, 2,6-diamine-para-xylene, and 2,5-diamine-para-xylene) with DGEBA as shown in Reaction 19 reproduced below:

Reaction 19

[0074] Thermoset polymer P7 was prepared by reacting DGEBA with an equimolar ratio of isomers of ortho-xylene diamine (3,5-diamine-ortho-xylene, 3,6-diamine-ortho-xylene, 4,5- diamine-ortho-xylene, and 3,4-diamine-ortho-xylene) as shown in Reaction 20 reproduced below under the same reaction conditions discussed above:

Reaction 20

[0075] Thermoset polymer P8 was prepared by reacting DGEBA with a mixture of diamine isomers of tetralin to form thermoset polymer P8 as illustrated in Reaction 21 reproduced below: Reaction 21

[0076] Thermoset polymer P9 was prepared by reacting DGEBA with a mixture of isomers of ortho-, meta-, and para-xylene diamine (3,5-diamine-ortho-xylene, 3,6-diamine-ortho-xylene, 4,5- diamine-ortho-xylene, 3,4-diamine-ortho-xylene, 4,6-diamine-meta-xylene, 2,6-diamine-meta- xylene, 2,3-diamine-para-xylene, 2,6-diamine-para-xylene, and 2,5-diamine-para-xylene) as illustrated in Reaction 22 reproduced below:

Reaction 22

[0077] The thermal stability of thermoset polymers P4, P5, P6, P7, P8, and P9 was analyzed by thermal gravimetric analysis (TGA) at a heating rate of 10 °C min'¹ from ambient temperature up to 700 °C under nitrogen. The mass loss profiles for thermoset polymers P4, P5, P6, P7, P8, and P9 are depicted in FIG. 6. The initial decomposition temperature can be considered as the temperature at which the weight loss is 5 wt% which begins at 362 °C, 361 °C, 345 °C, 346 °C, 343 °C, and 355 °C for P4, P5, P6, P7, P8, and P9, respectively. The thermal degradation behavior is classified into one-step as revealed in FIG. 6 indicating that there is no significant difference between the thermoset polymers issued from a mixture of isomers of meta-xylene diamine (4,6- diamine-meta-xylene and 2,6-diamine-meta-xylene) as curing agent (P5), a mixture of isomers of para-xylene diamine (2,3-diamine-para-xylene, 2,6-diamine-para-xylene, and 2,5-diamine-para- xylene) as curing agent (P6), a mixture of isomers of ortho-xylene diamine (3,5-diamine-ortho- xylene, 3,6-diamine-ortho-xylene, 4,5-diamine-ortho-xylene, and 3,4-diamine-ortho-xylene) as curing agent (P7), a mixture of diamine isomers of tetralin (P8), and a mixture of isomers of ortho- , meta-, and para-xylene diamine (3,5-diamine-ortho-xylene, 3,6-diamine-ortho-xylene, 4,5- diamine-ortho-xylene, 3,4-diamine-ortho-xylene, 4,6-diamine-meta-xylene, 2,6-diamine-meta- xylene, 2,3-diamine-para-xylene, 2,6-diamine-para-xylene, and 2,5-diamine-para-xylene) (P9). [0078] The glass transition temperature (T_g) was investigated by differential scanning calorimetry (DSC). FIG. 7 illustrates the DSC curves of the thermoset polymers P4, P5, P6, P7, P8, and P9. Scans were performed at a rate of 10 °C min'¹ and the results from the second heating scan from ambient temperature to up to 250 °C were used to determine the T_g value of the thermoset polymers (FIG. 7). Thermoset polymers P4, P5, P6, P7, P8, and P9 showed distinct T_g at 172 °C, 156 °C, 159 °C, 148 °C, 145 °C, and 155 °C, respectively. Summary of the results for the glass transition temperature (T_g) and for the initial decomposition temperature are in Table 2 below:

Table 2

[0079] Therefore, the methods of the present disclosure provide thermoset polymers with similar performance without the need for separation, saving energy, time, and money. Accordingly, the preceding description describes examples of processes and systems for producing thermoset polymers using epoxy resins with mixture of isomers aromatic diamines as curing agent. The processes and systems disclosed herein may include any of the various features disclosed herein, including one or more of the following embodiments.

[0080] Statement 1. A method comprising nitrating at least a portion of an aromatic feed to produce a mixture of isomers of nitrated aromatic compounds, hydrogenating at least a portion of the mixture of isomers of nitrated aromatic compounds to produce a mixture of isomers of aromatic amine monomers, and reacting the mixture of isomers of aromatic amines with an epoxy resin to produce at least a thermoset polymer.

[0081] Statement 2. The method of Statement 1, wherein the aromatic feed comprises a mixture of benzene, toluene, and xylene.

[0082] Statement 3. The method of Statement 1 or 2, wherein the aromatic feed comprises steam cracked tar.

[0083] Statement 4. The method of any preceding Statement, wherein the aromatic feed comprises a mixture of isomers of xylene. [0084] Statement 5. The method of any preceding Statement, wherein the nitrating occurs at a temperature of about 50 °C to about 100 °C and a pressure of about 1 bar to about 10 bar with a residence time in a nitration reactor of about 2 hours to about 48 hours with 20% to 60% conversion of the aromatic feed to the nitrated aromatic compounds, and wherein the hydrogenating occurs at a temperature of about 50 °C to about 100 °C and a pressure of about 10 bar to about 40 bar with a residence time in a nitration reactor of about 2 hours to about 48 hours with 15% to 70% conversion of the nitrated aromatic compounds to the aromatic amine monomers.

[0085] Statement 6. The method of any preceding Statement, wherein the isomers of the aromatic amine monomers comprise a first isomer present in an amount of about 1 wt% to about 99 wt% and a second isomer present in an amount of about 1 wt% to about 99 wt%.

[0086] Statement 7. The method of any preceding Statement, wherein the isomers of the aromatic amine monomers further comprise a third isomer present in an amount of about 1 wt% to about 99 wt%.

[0087] Statement 8. The method of any preceding Statement, wherein the thermoset polymer comprises repeating units with tertiary amines in at least three different isomeric positions.

[0088] Statement 9. The method of any preceding Statement, wherein the thermoset polymer comprises: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isometric position; and third repeating units of the epoxy group and a third tertiary amine having a third isometric position; wherein the first, second, and third isometric positions are different.

[0089] Statement 10. The method of any preceding Statement, wherein the first, second, and third repeating units are each present in an amount individually selected from about 5 wt% or more.

[0090] Statement 11. The method of any preceding Statement, wherein the mixture of isomers of aromatic amines is formulated to tune the curing profile of the mixture of isomers of aromatic amines with the epoxy resin.

[0091] Statement 12. A method comprising: providing a mixture of isomers of aromatic amines; and reacting the mixture of isomers of aromatic amines with at least an epoxy resin to produce at least a thermoset polymer comprising: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isometric position; third repeating units of the epoxy group and a third tertiary amine having a third isometric position; wherein the first, second, and third isometric positions are different.

[0092] Statement 13. The method of Statement 12, wherein the isomers of the aromatic amine monomers comprise a first isomer present in an amount of about 1 wt% to about 99 wt%, a second isomer present in an amount of about 1 wt% to about 99 wt%, and a third isomer present in an amount of about 1 wt% to about 99 wt%.

[0093] Statement 14. The method of Statement 12 or 13, wherein the thermoset polymer comprises repeating units with tertiary amines in at least three different isomeric positions.

[0094] Statement 15. The method of any of Statements 12-14, wherein the thermoset polymer comprises: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isometric position; and third repeating units of the epoxy group and a third tertiary amine having a third isometric position; wherein the first, second, and third isometric positions are different, wherein the first, second, and third repeating units are each present in an amount individually selected from about 5 wt% or more.

[0095] Statement 16. The method of any of Statements 12-15, wherein the mixture of isomers of aromatic amines comprises a mixture of isomers of tetralin.

[0096] Statement 17. The method of any of Statements 12-16, wherein the mixture of isomers of aromatic amines comprises a mixture of isomers of benzene, toluene, and xylene.

[0097] Statement 18. The method of any of Statements 12-17, wherein the mixture of isomers of aromatic amines comprises diglycidyl ether of bisphenol A (DGEBA).

[0098] Statement 19. The method of any of Statements 12-18, wherein the mixture of isomers of aromatic amines comprises diglycidyl ether of bisphenol F (DGEBF).

[0099] Statement 20. A thermoset polymer product comprising: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isomeric position; third repeating units of the epoxy group and a third tertiary amine having a third isomeric position; wherein the first, second, and third isomeric positions are different, and wherein the first, second, and third repeating units are each present in the thermoset polymer product in an amount of about 5 wt% or more.

[00100] While the disclosure has been described with respect to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the disclosure as disclosed herein. Although individual embodiments are discussed, the present disclosure covers all combinations of all those embodiments.

[00101] While compositions, methods, and processes are described herein in terms of “comprising,” “containing,” “having,” or “including” various components or steps, the compositions and methods can also “consist essentially of’ or “consist of’ the various components and steps. The phrases, unless otherwise specified, “consists essentially of’ and “consisting essentially of’ do not exclude the presence of other steps, elements, or materials, whether or not, specifically mentioned in this specification, so long as such steps, elements, or materials, do not affect the basic and novel characteristics of the disclosure, additionally, they do not exclude impurities and variances normally associated with the elements and materials used. [00102] All numerical values within the detailed description and the claims herein modified by “about” or “approximately” with respect the indicated value are intended to take into account experimental error and variations that would be expected by a person having ordinary skill in the art. For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited.

Claims

CLAIMS:

1. A method comprising: nitrating at least a portion of an aromatic feed to produce a mixture of isomers of nitrated aromatic compounds; hydrogenating at least a portion of the mixture of isomers of nitrated aromatic compounds to produce a mixture of isomers of aromatic amine monomers; and reacting the mixture of isomers of aromatic amines with an epoxy resin to produce at least a thermoset polymer.

2. The method of claim 1, wherein the aromatic feed comprises a mixture of benzene, toluene, and xylene.

3. The method of claim 1, wherein the aromatic feed comprises steam cracked tar.

4. The method of claim 1, wherein the aromatic feed comprises a mixture of isomers of xylene.

5. The method of claim 1, wherein the nitrating occurs at a temperature of about 50 °C to about 100 °C and a pressure of about 1 bar to about 10 bar with a residence time in a nitration reactor of about 2 hours to about 48 hours with 20% to 60% conversion of the aromatic feed to the nitrated aromatic compounds, and wherein the hydrogenating occurs at a temperature of about 50 °C to about 100 °C and a pressure of about 10 bar to about 40 bar with a residence time in a nitration reactor of about 2 hours to about 48 hours with 15% to 70% conversion of the nitrated aromatic compounds to the aromatic amine monomers.

6. The method of claim 1, wherein the isomers of the aromatic amine monomers comprise a first isomer present in an amount of about 1 wt% to about 99 wt% and a second isomer present in an amount of about 1 wt% to about 99 wt%.

7. The method of claim 1, wherein the isomers of the aromatic amine monomers further comprise a third isomer present in an amount of about 1 wt% to about 99 wt%.

8. The method of claim 1, wherein the thermoset polymer comprises repeating units with tertiary amines in at least three different isomeric positions.

9. The method of claim 1, wherein the thermoset polymer comprises: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isometric position; and third repeating units of the epoxy group and a third tertiary amine having a third isometric position; wherein the first, second, and third isometric positions are different.

10. The method of claim 9, wherein the first, second, and third repeating units are each present in an amount individually selected from about 5 wt% or more.

11. The method of claim 1, wherein the mixture of isomers of aromatic amines is formulated to tune the curing profile of the mixture of isomers of aromatic amines with the epoxy resin.

12. A method comprising: providing a mixture of isomers of aromatic amines; and reacting the mixture of isomers of aromatic amines with at least an epoxy resin to produce at least a thermoset polymer comprising: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isometric position; third repeating units of the epoxy group and a third tertiary amine having a third isometric position; wherein the first, second, and third isometric positions are different.

13. The method of claim 12, wherein the isomers of the aromatic amine monomers comprise a first isomer present in an amount of about 1 wt% to about 99 wt%, a second isomer present in an amount of about 1 wt% to about 99 wt%, and a third isomer present in an amount of about 1 wt% to about 99 wt%.

14. The method of claim 12, wherein the thermoset polymer comprises repeating units with tertiary amines in at least three different isomeric positions.

15. The method of claim 12, wherein the thermoset polymer comprises: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isometric position; and third repeating units of the epoxy group and a third tertiary amine having a third isometric position; wherein the first, second, and third isometric positions are different, wherein the first, second, and third repeating units are each present in an amount individually selected from about 5 wt% or more.

16. The method of claim 12, wherein the mixture of isomers of aromatic amines comprises a mixture of isomers of tetralin.

17. The method of claim 12, wherein the mixture of isomers of aromatic amines comprises a mixture of isomers of benzene, toluene, and xylene.

18. The method of claim 12, wherein the mixture of isomers of aromatic amines comprises diglycidyl ether of bisphenol A (DGEBA).

19. The method of claim 12, wherein the mixture of isomers of aromatic amines comprises diglycidyl ether of bisphenol F (DGEBF).

20. A thermoset polymer product comprising: first repeating units of an epoxy group and a first tertiary amine having a first isomeric position; second repeating units of the epoxy group and a second tertiary amine having a second isomeric position; third repeating units of the epoxy group and a third tertiary amine having a third isomeric position; wherein the first, second, and third isomeric positions are different, and wherein the first, second, and third repeating units are each present in the thermoset polymer product in an amount of about 5 wt% or more.