Solvent for carbon nanotube dispersions

Abstract

The present disclosure provides compositions and methods for dispersing CNTs using a CNT solvent comprising an aromatic ring structure comprising at least one sulfonic acid functional group. Alternatively, the aromatic ring structure further comprises at least a linear or branched alkyl chain. Examples of carbon nanotube solvents include dodecylbenzene sulfonic acid.

Description

field

[0001] The present disclosure relates to dispersions of carbon nanotubes (CNTs), and more particularly to CNT dispersions using a CNT solvent comprising an aromatic ring structure including at least one sulfonic acid functional group and optionally at least one alkyl chain. background

[0002] Carbon nanotubes (CNT) are usually produced in large quantities as powders. However, in powder form, CNT is not particularly useful because their aerial density (aerial density) is low and it is difficult to further dry process into stable structures. However, when dispersed in a solvent, CNT can be shaped into the desired form of a series of applications by various means. For example, when stable in a low concentration suspension, CNT dispersions can be used as precursors for purposes such as solution-cast nanocomposites, high surface area battery materials, conductive coatings, films and transistor arrays of displays. At higher concentrations, CNT suspensions can have additional uses, including but not limited to conductive inks for printed electronics or liquid crystal forms, wet spinning into fibers of composite materials or cables. In gel or paste form, CNT can be 3D printed / molded into CNT-rich products for structural applications.

[0003] A key barrier to the widespread use of CNTs in various markets is the inability to reliably process them from the solution state into the desired form. This is due to the low stability of CNTs in most common solvents, which is attributed to various factors such as their high aspect ratio, high molecular weight and weakly interacting native surface. In addition, due to their highly entangled and pre-aggregated dry form, they are difficult to disperse into much smaller entities, bundles or even single discrete nanotubes.

[0004] To this end, various methods have been developed to debundle or disentangle carbon nanotubes in solution. One method involves sonication of carbon nanotubes in the presence of a surfactant, but the resulting dispersions often contain surfactant or dispersant residues that cannot be removed, thus limiting commercial use. Other methods involve shortening the carbon nanotubes before dispersing the individual nanotubes in a dilute solution. However, such dilute solutions often contain nanotube concentrations that are generally insufficient for commercial use.

[0005] Solvents for dispersing CNTs include superacids, such as chlorosulfuric acid, which disperse CNTs by surface protonation, thereby forming a net repulsion between nanotubes. In addition to superacids, alkali metals have also been used to disperse CNTs. However, both of these solvent families have the disadvantage of limiting their commercial use with CNTs. For example, both of these solvent families are highly reactive to other chemicals (e.g., water), require highly specialized operating conditions, may leave residues or chemically modify CNTs, and are incompatible with other components when the processed material is combined in product formulations, such as inkjet printing or composite material manufacturing. Overview

[0006] Disclosed herein is a method comprising combining carbon nanotubes in a dry form with a carbon nanotube solvent; and mixing the carbon nanotubes and the carbon nanotube solvent to form a carbon nanotube suspension of the carbon nanotubes in the carbon nanotube solvent, wherein the carbon nanotube solvent has an aromatic ring structure further comprising at least a sulfonic acid functional group.

[0007] In one aspect, the present disclosure provides a composition including a carbon nanotube solvent and carbon nanotubes dispersed in the carbon nanotube solvent, the carbon nanotube solvent having an aromatic ring structure further including at least a sulfonic acid functional group.

[0008] These and other features and properties of the disclosed methods and systems of the present disclosure and their advantageous applications and / or uses will be apparent from the following detailed description. Details

[0009] The present application relates to methods and systems for dispersing CNTs, and more particularly to dispersing CNTs using a CNT solvent comprising an aromatic ring structure, the aromatic ring structure further comprising at least one sulfonic acid functional group. The aromatic ring structure may further comprise an alkyl chain. In at least one embodiment, the aromatic ring structure is present in crude oil.

[0010] CNT is a cylindrical molecule made of carbon. As used herein, the term carbon nanotube or CNT includes single-walled CNT and multi-walled CNT. Single-walled CNT is a cylindrical molecule with a diameter of 3nm or less formed by a single carbon atom layer. For example, a single-walled CNT is a graphene sheet rolled into a cylindrical shape. Single-walled CNTs generally have a diameter close to 1nm, such as 3nm or less, 2nm or less, or 1nm or less. Multi-walled CNTs include several concentrically interconnected tubes made of carbon. Multi-walled CNTs have a diameter of 50nm or less, such as 1nm to 15nm or 1nm to 10nm. Whether single-walled or multi-walled, the length of CNT is generally much longer than its diameter, and can have an aspect ratio of 1000 or more. For example, CNT can have an aspect ratio of 50 to 5,000, 100 to 5,000, 500 to 5,000, or 1,000 to 5,000. CNT length can reach several microns or even several millimeters.

[0011] As mentioned above, the development of liquid processing of CNTs is particularly challenging due to the processing difficulties of liquid CNTs. CNTs do not dissociate due to the strong carbon-carbon bonds (CC) in the CNT walls, and they are insoluble in organic or aqueous solvents. Due to the strong van der Waals forces between their side walls as mentioned above, CNTs tend to form bundles rather than dissolve. This is problematic because nanotubes can only be controlled and arranged in solution if they are well dispersed and distributed in suspension.

[0012] According to the present embodiment, CNTs in dry form are dispersed using CNT solvents with aromatic ring structures. As used herein, it is mentioned that dry CNTs are intended to be included in powder form, pulp and aerogel CNTs, but it is not intended to include slurry (slurry) form or otherwise wetted CNTs. The aromatic ring structure of CNT solvents includes at least one sulfonic acid functional group. In addition, the aromatic ring structure of CNT solvents may also include at least one alkyl chain, which may be linear or branched. Suitable ring structures are aromatic rings with 1-membered rings, or 2-membered rings, or 3-membered rings, or 4-membered rings, or 5-membered rings, or 6-membered rings, or 7-membered rings, or 8-membered rings or more. In some embodiments, the ring is a carbocyclic ring, including benzene, toluene, ethylbenzene, xylene, cumene, mesitylene, durene, unsaturated cycloolefins, unsaturated cyclopentenes, saturated cycloalkanes, polycyclic aromatic hydrocarbons such as naphthalene, partially hydrogenated derivatives of naphthalene such as tetralin, anthracene or phenanthrene, pyrene or any combination thereof. In some embodiments, the ring structure includes at least one heteroatom, such as oxygen, nitrogen or sulfur.

[0013] The aromatic ring includes a straight or branched alkyl chain. The alkyl chain can be substituted or unsubstituted. The alkyl chain can have any suitable chain length, including 1 carbon to 50 carbons or 6 carbons to 50 carbons. In some embodiments, the alkyl chain includes 10 carbons to 50 carbons, 10 carbons to 30 carbons, 10 carbons to 20 carbons. In a particular embodiment, the alkyl chain includes 12 carbons. As shown in the following examples, compared with the same aromatic ring structure of unsulfonated, the aromatic ring structure (4-dodecylbenzene sulfonic acid) including a sulfonic acid group and a monocyclic alkyl chain of 12 carbons is shown to provide a good dispersion of CNT. In addition, the alkyl chain can be in the meta position of the sulfonic acid group, or in the ortho position of the sulfonic acid group or in the para position of the sulfonic acid group.

[0014] Exemplary embodiments include monocyclic aromatic compounds containing at least one sulfonic acid functional group. Alternatively, other exemplary embodiments include monocyclic aromatic compounds containing at least one sulfonic acid functional group and at least one alkyl chain to obtain the following structure. The following structure is an example of a monocyclic aromatic compound containing at least one sulfonic acid functional group and optionally at least one alkyl chain:

[0015] Exemplary embodiments include bicyclic aromatic compounds comprising at least one sulfonic acid functional group. Alternatively, other exemplary embodiments include bicyclic aromatic compounds comprising at least one sulfonic acid functional group and at least one alkyl chain to obtain the following structure. The following structure is an example of a bicyclic aromatic compound comprising at least one sulfonic acid functional group and optionally at least one alkyl chain:

[0016] Exemplary embodiments include a tricyclic aromatic compound comprising at least one sulfonic acid functional group and at least one alkyl chain to give the following structure:

[0017] In some embodiments, the CNT solvent includes a mixture of aromatic ring structures that have been sulfonated, for example:

[0018] Any suitable technique may be used to prepare the CNT dispersant. For example, the ring structure may include at least one sulfonic acid group. Alternatively, the ring structure may include at least one sulfonic acid group and at least one alkyl chain of any length selected as in the cited structural unit. For example, a suitable aromatic ring structure is formed by sulfonation of an aromatic ring structure having an alkyl chain of 1 to 50 carbons. As shown in the following reaction, an exemplary embodiment includes sulfonating dodecylbenzene to 4-dodecylbenzene sulfonic acid:

[0019] The aromatic ring structure for CNT solvent can be obtained from any suitable source. In a specific embodiment, the CNT aromatic ring is from crude oil. For example, a suitable CNT solvent with an aromatic ring structure for forming a sulfonated aromatic ring structure can be obtained from various refinery process streams. In some embodiments, the aromatic ring structure from the refinery process stream includes an alkyl group. In some embodiments, an alkyl group is added to the aromatic ring structure from the refinery process stream. In some embodiments, the refinery process stream containing aromatic hydrocarbons and aromatic heterocyclic compounds suitable for the present disclosure may include or be derived from, for example, steam cracker tar, main column bottoms, vacuum residue, heavy aromatic reforming oil (e.g., C9, C 10 , C 11 or C 12 ), motor gasoline (mogas), naphtha, C5 rock, C3-C5 rock, slurry oil, asphaltenes, asphalt, K-pot bottoms, lubricating oil extracts and any combination thereof. These terms are familiar to those of ordinary skill in the art. A specific discussion of these refinery process streams is provided below. Exemplary embodiments include sulfonating aromatic ring structures obtained from these refinery process streams.

[0020] In some embodiments, steam cracker tar (also referred to as steam cracking tar or pyrolysis fuel oil) may contain a suitable source of aromatic ring structures. "Steam cracker tar" is a high molecular weight material obtained after pyrolysis of a hydrocarbon feedstock into olefins. Suitable steam cracker tar may be one from which asphaltenes may or may not have been removed. Steam cracker tar may be obtained as a bottom product of the fractionator from the first fractionator downstream of the steam cracker (pyrolysis furnace), nominally having a boiling point of 288°C and higher. In a particular embodiment, steam cracker tar can be obtained from a pyrolysis furnace, which produces a gas phase including ethylene, propylene and butenes; a liquid phase separated as an overhead phase in a primary fractionation step, which comprises C5+ species, including a naphtha fraction (e.g., C3-C10 species) and a steam cracked gas oil fraction (mainly C10-C15 / C17 species with an initial boiling range of about 204°C to 288°C); and a bottoms fraction, which comprises steam cracker tar having a boiling point range above about 288°C and comprising C15 / C17+ species.

[0021] In some embodiments, the main tower bottoms (also referred to as FCC main tower bottoms or slurry oil) may contain a suitable source of aromatic ring structures. Typical aromatic ring structures that may be present in the main tower bottoms include those with a molecular weight of about 250 to about 1000. In some cases, there may be 1 to 8 fused aromatic rings. Suitable main tower bottoms may be ones from which asphaltenes have or have not been removed. Residual cracking catalyst that is not removed by cyclone after cracking may remain present in the main tower bottoms, or may not remain present in the main tower bottoms. Main tower bottoms containing catalysts and those not containing catalysts are all applicable to the present disclosure.

[0022] Vacuum residue may contain a suitable source of aromatic ring structures. As the name implies, "vacuum residue" is the residual material obtained from a distillation column after vacuum distillation. Vacuum residue may have a nominal boiling point range of about 600°C or higher.

[0023] C3 rock or C3-C5 rock may contain a suitable source of aromatic ring structures. C3-C5 rock refers to asphaltenes that have been further treated with propane, butane and pentane in a deasphalting unit. Likewise, C3 rock refers to asphaltenes that have been further treated with propane. C3 and C3-C5 rock may have high metal content (such as Ni and V) and may contain a large number of N and S heteroatoms in the heteroaromatic rings.

[0024] In some embodiments, bitumen or asphaltenes may comprise a suitable source of aromatic ring structures. Some sources consider bitumen and asphaltenes to be synonymous with each other. Typically, asphaltenes refer to materials of a solubility grade that precipitates or separates from oil when in contact with paraffins (e.g., propane, butane, pentane, hexane, or heptane). Bitumen traditionally refers to materials obtained from oil sands, and represents a full range of materials with higher boiling points than crude petroleum.

[0025] Another suitable source of aromatic ring structures includes light aromatic streams, including, for example, aromatic compounds from catalytic reforming or steam cracking (e.g., BT(E)X and pyrolysis gasoline), reformate from a catalytic reformer, or mixed linear or branched alkylated naphthalenes. Exemplary embodiments include sulfonating aromatic ring structures obtained from these light aromatic streams.

[0026] Another suitable source of aromatic ring structures includes those derived from 6+ The aromatic ring structure of the heavy fraction naphtha of fluid catalytic cracking (FCC) of aromatic compounds. Exemplary embodiments include the processing of hydrocarbon feeds, including from 6+ Extracting aromatic compounds from heavy fraction naphtha of FCC of aromatic compounds, sulfonating the extracted aromatic compounds containing optional alkyl chains, and reacting CNT with sulfonated CNT 6+In some embodiments, a liquid-liquid extraction (LLE) system is used to complete the C 6+ Aromatic compound extraction. Alternatively, C 6+ The aromatics extraction unit is an extractive distillation (ED) system.

[0027] In one or more embodiments, C is extracted from the catalytic reforming unit. 6+ Aromatic compounds, then the extracted C 6+ The aromatic compound is sulfonated and the sulfonated C6 + Aromatic compounds are mixed with CNTs.

[0028] In one or more embodiments, C is extracted from heavy vacuum gas oil. 6+ Aromatic compounds, then the extracted C 6+ The aromatic compound is sulfonated and the sulfonated C 6+ Aromatic compounds are mixed with CNTs.

[0029] The CNT solvent can be used to disperse CNTs at any suitable ratio. In some embodiments, CNTs are contained in the CNT solvent in an amount of 0.01 mg to 1 mg per milliliter of CNT solvent. For example, CNTs are contained in an amount of 0.02 mg to 1 mg, 0.05 mg to 1 mg, 0.1 mg to 1 mg, 0.01 mg to 0.5 mg, or 0.1 mg to 0.5 mg per milliliter of CNT solvent.

[0030] Any suitable technology can be used to prepare CNT solvent.For example, the ring structure may include at least one sulfonic acid group and / or at least one alkyl chain of any length.Then the CNT in dry form is merged with the CNT solvent, and then the mixture is mixed. Any of various suitable technologies can be used to mix CNT and CNT solvent, including mechanical stirring and sonication.In some embodiments, before the CNT solvent is functionalized with at least one sulfonic acid group and at least one optional alkyl chain, CNT is directly merged with the CNT solvent, without merging CNT with another solvent.As shown in the following examples, compared with using unsulfonated CNT solvent, the direct merging of CNT in dry form with the CNT solvent provides a stable CNT dispersion.

[0031] Therefore, the present disclosure provides compositions and methods for dispersing CNTs using a CNT solvent containing an aromatic ring structure, the aromatic ring structure including at least one sulfonic acid functional group and at least one optional alkyl chain. The compositions and methods may include any of the various features disclosed herein, including one or more of the following statements.

[0032] Embodiment 1. A method comprising: combining dried carbon nanotubes with a carbon nanotube solvent, wherein the carbon nanotube solvent has an aromatic ring structure including at least a sulfonic acid functional group; and mixing the carbon nanotubes and the carbon nanotube solvent to form a carbon nanotube suspension of the carbon nanotubes in the carbon nanotube solvent.

[0033] Embodiment 2. The method of embodiment 1, wherein the aromatic compound of the carbon nanotube solvent comprises a monocyclic or bicyclic aromatic compound.

[0034] Embodiment 3. The method of Embodiment 1, wherein the aromatic compound of the carbon nanotube solvent comprises a tricyclic aromatic compound.

[0035] Embodiment 4. The method of any one of Embodiments 1-3, wherein the aromatic ring structure further comprises at least one linear or branched alkyl chain.

[0036] Embodiment 5. The method of any one of Embodiments 1-4, wherein the alkyl chain of the carbon nanotube solvent comprises from 1 carbon to 10 carbons.

[0037] Embodiment 6. The method of any one of Embodiments 1-5, wherein the alkyl chain of the carbon nanotube solvent comprises from 10 carbons to 50 carbons.

[0038] Embodiment 7. The method of any one of Embodiments 1-6, wherein the carbon nanotube solvent comprises dodecylbenzenesulfonic acid.

[0039] Embodiment 8. The method of any one of Embodiments 1-7, wherein the carbon nanotube solvent comprises a mixture having sulfonated structures 32-34.

[0040] Embodiment 9. The method of any one of Embodiments 1-8, wherein the aromatic structure of the carbon nanotube solvent comprises at least one heteroatom.

[0041] Embodiment 10. The method of any one of Embodiments 1-9, wherein the aromatic structure of the carbon nanotube solvent is extracted from a refinery process stream.

[0042] Embodiment 11. The method of any one of embodiments 1-10, wherein the aromatic structure of the carbon nanotube solvent is extracted from a carbon nanotube solvent containing C 6+ Fluid catalytic cracking of naphtha with aromatic compounds.

[0043] Embodiment 12. The method of any one of Embodiments 1-11, further comprising separating the aromatic structures from the fluid catalytic cracked naphtha using liquid-liquid extraction.

[0044] Embodiment 13. The method of any one of Embodiments 1-12, further comprising separating the aromatic structures from the fluid catalytic cracked naphtha using extractive distillation.

[0045] Embodiment 14. The method of any of Embodiments 1-13, wherein the aromatic structure of the carbon nanotube solvent is extracted from a process stream from a catalytic reforming unit.

[0046] Embodiment 15. The method of any one of Embodiments 1-14, wherein the aromatic structure of the carbon nanotube solvent is extracted from vacuum gas oil.

[0047] Embodiment 16. A composition comprising: a carbon nanotube solvent having an aromatic ring structure including at least a sulfonic acid functional group; and carbon nanotubes dispersed in the carbon nanotube solvent.

[0048] Embodiment 17. The composition of Embodiment 16, wherein the aromatic ring structure further comprises an alkyl chain.

[0049] Embodiment 18. The composition of any one of Embodiments 16-17, wherein the aromatic ring structure of the carbon nanotube solvent comprises benzene or xylene.

[0050] Embodiment 19. The composition of any one of Embodiments 16-18, wherein the aromatic ring structure of the carbon nanotube solvent comprises naphthalene or biphenyl.

[0051] Embodiment 20. The composition of any one of Embodiments 16-19, wherein the aromatic ring structure of the carbon nanotube solvent comprises at least one of anthracene or phenanthrene.

[0052] Embodiment 21. The composition of any one of Embodiments 16-20, wherein the aromatic ring structure of the carbon nanotube solvent comprises at least one heteroatom.

[0053] Embodiment 22. The composition of any of Embodiments 16-21, wherein the carbon nanotube solvent comprises a dodecyl alkyl chain.

[0054] Embodiment 23. The composition of any of Embodiments 16-22, wherein the carbon nanotube solvent comprises dodecylbenzenesulfonic acid.

[0055] Embodiment 24. The composition of any one of Embodiments 16-23, wherein the carbon nanotube solvent comprises a mixture of structures 32-34 having sulfonation.

[0056] Embodiment 25. The composition of any one of Embodiments 16-24, wherein the carbon nanotubes are dispersed in the carbon nanotube solvent in an amount of about 0.01 mg to about 1 mg per milliliter of carbon nanotube solvent. Example Example 1

[0057] The following example is carried out to illustrate the synthesis of 4-dodecylbenzene sulfonic acid by the sulfonation of 4-dodecylbenzene. In order to prepare sulfonated 4-dodecylbenzene, 44% silica sulfuric acid (5.62g, 0.0229mol, 1 equivalent) and dodecylbenzene (5g, 0.0229mol, mw: 218.12, 1 equivalent) in 1,2-dichloroethane (100ml) are introduced into a 350ml round-bottom flask. The reaction mixture is stirred at reflux temperature for 18 hours. The heterogeneous mixture is then filtered and washed with dichloromethane (1x30ml). The solvent is then removed under pressure, and the product is then washed with hexane (2x20 ml) and dried under vacuum at ambient temperature. As shown in the following reaction 2, the dodecyl group can be in the meta position (not shown) or the para position or the ortho position of the sulfate group: Example 2

[0058] The following examples are carried out to illustrate the sulfonation of bicyclic aromatic structures. To prepare the sulfonated bicyclic aromatic structure, 44% silica sulfuric acid (11.24 g, 0.183 mol, 2 equivalents) and 1-methylnaphthalene (3.25 g, 0.0229 mol, mw: 142.20, 1 equivalent) in 1,2-dichloroethane (100 ml) are introduced into a 350 ml round-bottom flask. The reaction mixture is stirred at reflux temperature for 18 hours. The heterogeneous mixture is then filtered and washed with dichloromethane (1x30 ml). The solvent is removed under pressure, and the product is washed with hexane (2x20 ml) and dried under vacuum at ambient temperature. The methyl group can be in the meta position (not shown) or the para or ortho position of the sulfate group, and the two sulfonic acid groups can also be combined as shown in reaction 3: Example 3

[0059] The following examples are carried out to illustrate how the addition of sulfonic acid groups improves the performance of CNT solvents. Dodecylbenzene contains an aromatic structure. However, it lacks sulfonic acid functional groups. Therefore, 4-dodecylbenzene sulfonic acid is obtained and its performance as a CNT solvent is compared with dodecylbenzene. In order to test the performance, CNTs in a dry form are directly added to dodecylbenzene in an amount of 0.0018 mg / ml or about 2 ppm. This mixture is sonicated for 1 hour at 50% duty cycle and then left to store. After a few hours, CNTs settle to the bottom of dodecylbenzene. This test is repeated for 4-dodecylbenzene sulfonic acid at a concentration of 1.1 mg / mL. Compared with dodecylbenzene, sulfonation of dodecylbenzene to 4-dodecylbenzene sulfonic acid converts it into an excellent solvent for dispersing CNTs. CNTs remain suspended in 4-dodecylbenzene sulfonic acid while the mixture forms a thick paste that is stable for several weeks.

[0060] Although the present disclosure has been described with reference to a number of embodiments and examples, those skilled in the art who have benefited from the present disclosure will recognize that other embodiments can be designed that do not depart from the scope and spirit of the present disclosure as disclosed herein. Although various embodiments are discussed, the present disclosure encompasses all combinations of all such embodiments.

[0061] Although compositions, methods and processes are described herein as "comprising," "containing," "having," or "including" various components or steps, the compositions and methods may also "consist essentially of" or "consist of" the various components and steps. Unless otherwise indicated, the phrase "consisting essentially of" does not exclude the presence of other steps, elements, or materials, whether or not specifically mentioned in the specification, as long as these steps, elements, or materials do not affect the basic and novel characteristics of the disclosure, and further, they do not exclude impurities and variations normally associated with the elements and materials used.

[0062] All numerical values ​​within the detailed description are modified by "about" the indicated value, and take into account experimental error and variations that would be expected by a person of ordinary skill in the art.

[0063] Numerous variations, modifications and variations will be apparent to those skilled in the art from the foregoing description without departing from the spirit or scope of the disclosure, and when numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated.

Claims

1. A method comprising: combining the dried carbon nanotubes with a carbon nanotube solvent, wherein the carbon nanotube solvent has an aromatic ring structure including at least a sulfonic acid functional group; and The carbon nanotubes and the carbon nanotube solvent are mixed to form a carbon nanotube suspension of the carbon nanotubes in the carbon nanotube solvent. 2 . The method according to claim 1 , wherein the aromatic compound of the carbon nanotube solvent comprises a single-ring aromatic compound. The method according to claim 1 , wherein the aromatic compound of the carbon nanotube solvent comprises a bicyclic aromatic compound. The method according to claim 1 , wherein the aromatic compound of the carbon nanotube solvent comprises a tricyclic aromatic compound. The method according to claim 1 , wherein the aromatic ring structure further comprises at least one linear or branched alkyl chain. The method of claim 5 , wherein the alkyl chain of the carbon nanotube solvent comprises 1 carbon to 10 carbons.

7. The method of claim 5, wherein the alkyl chain of the carbon nanotube solvent comprises 10 carbons to 50 carbons.

8. The method of claim 1, wherein the carbon nanotube solvent comprises dodecylbenzene sulfonic acid.

9. The method of claim 1, wherein the carbon nanotube solvent comprises a mixture having the following base structures sulfonated:

10. The method of claim 1, wherein the aromatic structure of the carbon nanotube solvent comprises at least one heteroatom.

11. The method of claim 1, wherein the aromatic structure of the carbon nanotube solvent is extracted from a refinery process stream.

12. The method according to claim 11, wherein the aromatic structure of the carbon nanotube solvent is extracted from a 6+ Fluid catalytic cracking of naphtha with aromatic compounds.

13. The method of claim 12, further comprising separating the aromatic structures from the fluid catalytic cracked naphtha using liquid-liquid extraction.

14. The method of claim 12, further comprising separating the aromatic structures from the fluid catalytic cracked naphtha using extractive distillation.

15. The method of claim 1, wherein the aromatic structure of the carbon nanotube solvent is extracted from a process stream from a catalytic reforming unit.

16. The method of claim 1, wherein the aromatic structure of the carbon nanotube solvent is extracted from vacuum gas oil.

17. A composition comprising: a carbon nanotube solvent having an aromatic ring structure including at least a sulfonic acid functional group; and The carbon nanotubes are dispersed in the carbon nanotube solvent.

18. The composition of claim 17, wherein the aromatic ring structure further comprises an alkyl chain.

19. The composition of claim 17, wherein the aromatic ring structure of the carbon nanotube solvent comprises at least one of benzene or xylene.

20. The composition of claim 17, wherein the aromatic ring structure of the carbon nanotube solvent comprises at least one of naphthalene or biphenyl.

21. The composition of claim 17, wherein the aromatic ring structure of the carbon nanotube solvent comprises at least one of anthracene or phenanthrene.

22. The composition of claim 17, wherein the aromatic ring structure of the carbon nanotube solvent comprises at least one heteroatom.

23. The composition of claim 17, wherein the carbon nanotube solvent comprises a dodecyl alkyl chain.

24. The composition of claim 17, wherein the carbon nanotube solvent comprises dodecylbenzene sulfonic acid.

25. The composition of claim 17, wherein the carbon nanotube solvent comprises a mixture having the following structures sulfonated:

26. The composition of claim 17, wherein the carbon nanotubes are dispersed in the carbon nanotube solvent in an amount of about 0.01 mg to about 1 mg per milliliter of carbon nanotube solvent.

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