A composition, a reaction apparatus and a method for synthesizing single-walled carbon nanotubes

Abstract

A composition, a reaction device and a preparation method of a single-walled carbon nanotube, the composition comprising: C n H 2n+2 80-95 parts by weight; C2-C3 polyhydric alcohol 5-20 parts by weight; organic transition metal catalyst 0.5-10 parts by weight; promoter 0.1-1.5 parts by weight; wherein n is an integer of 9-16; the scheme has the advantages of improving the production safety of the traditional floating catalytic cracking method, low raw material cost, stable and controllable production process, and high yield, and is suitable for large-scale production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single-walled carbon nanotubes, and in particular to a composition, a reaction device and a preparation method for synthesizing single-walled carbon nanotubes. BACKGROUND

[0002] Single-walled carbon nanotubes (SWCNT) are a new type of one-dimensional nanomaterial, which are widely used in new energy, transparent display, antistatic, semiconductor, engineering plastic and other fields due to their excellent electrical conductivity, thermal conductivity, temperature resistance, chemical resistance and mechanical properties. However, the batch production technology of SWCNT has been restricting its application in various fields, and therefore how to realize low-cost and scalable production is a problem to be solved.

[0003] Currently, there are three main ways to prepare single-walled carbon nanotubes: arc method, laser ablation method and chemical vapor deposition method. The existing arc method and laser ablation method have low yield and high energy consumption, and are difficult to realize large-scale production. The floating catalytic chemical vapor deposition method is the most batch production technology due to the continuity of raw material supply and product collection. For example, Chinese patents CN201811447415.8 and CN103204492A report a method for preparing single-walled carbon nanotubes by floating catalytic method, in which ferrocene or nickelocene is used as catalyst, and ethanol, methanol, n-hexane, toluene, xylene and other organic solvents are used as carbon source and injected into the reactor.

[0004] However, the carbon source in the existing floating catalytic cracking technology is generally low-flashpoint flammable liquid and flammable and explosive gas. Although the low-boiling flammable liquid has lower safety risk than CH4 and C2H2, there are still some safety hazards. In addition, the carrier gas in such methods is generally argon, helium, nitrogen and the like, but in order to control the diameter and purity of single-walled carbon nanotubes, hydrogen is usually used in combination, which further increases the safety hazard. In addition, the gasification rate of the small molecule gaseous or low-boiling liquid carbon source, promoter and other solid-state catalysts used in the above-mentioned prior art is poor in synchronization with the cracking temperature, and the synthesis window is narrow, which is not conducive to the improvement of the carbon source conversion efficiency in the floating catalytic cracking.

[0005] Therefore, it is urgent to develop a safe and efficient synthetic single-walled carbon nanotube formula composition to improve the problems in the above-mentioned technology. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a composition for synthesizing single-walled carbon nanotubes, which improves the production safety of the traditional floating catalytic cracking method, has low raw material cost, and has stable and controllable production process and high yield.

[0007] To achieve the above-mentioned objectives, the technical solution adopted in this application is: a composition for synthesizing single-walled carbon nanotubes, the composition comprising:

[0008]

[0009]

[0010] Wherein n is an integer from 9 to 16.

[0011] Furthermore, as a further aspect of the present invention: the C n H 2n+2 The alkanes have a carbon number n: 9≤n≤16, a molecular weight of 128~226g / mol, a boiling point >150℃, and a flash point ≥31℃. The role of the hydrocarbons with the above specifications is to provide the carbon atoms necessary for the growth of carbon nanotubes. At the same time, the alkanes with this specification can improve the solubility of the catalyst in the system.

[0012] Furthermore, the C2-C3 polyols are at least one of ethylene glycol, propylene glycol, and glycerol; these polyols are general chemicals, non-toxic, odorless, environmentally friendly, with a boiling point above 180°C, and are not flammable.

[0013] Furthermore, the C2-C3 polyols are ethylene glycol, glycerol, or a mixture of both with a C / O atomic ratio of 1 / 1; the proportion of O element in the reaction system is particularly important because O free radicals can react with CH free radicals that have not dissolved and deposited with the catalyst during the cracking process to form gaseous products that are discharged, thereby greatly improving the purity of the products.

[0014] Furthermore, the organic transition metal catalyst comprises one or more of ferrocene, cobalt dicene, and nickel dicene, and the sublimation temperature of the catalyst is >100°C.

[0015] Furthermore, the promoter is dimethyl sulfoxide with a boiling point of 189°C. This promoter can form a cophase with metal nanocatalyst particles, which is beneficial to the synthesis of single-walled carbon nanotubes.

[0016] The present invention also provides a reaction apparatus for the above-mentioned preparation method, the apparatus comprising a liquid vaporization device, a floating catalytic cracking reactor, and a product collection device; the liquid vaporization device is provided with an inlet pipe and a vaporization conveying pipe, the inlet pipe being used for gas introduction and the end of the inlet pipe extending into the interior of the liquid vaporization device; the vaporization conveying pipe is connected to the floating catalytic cracking reactor, and the floating catalytic cracking reactor is also connected to an inert gas inlet pipe; the product collection device is connected to the outlet end of the floating catalytic cracking reactor.

[0017] Furthermore, the liquid vaporization device also includes a heating device to fully heat the liquid vaporization device so that its internal heating temperature is not lower than 200°C.

[0018] Furthermore, the furnace tube of the floating catalytic cracking reactor is a corundum reactor with an inner diameter of 30mm to 150mm and a constant temperature zone length of not less than 300mm. Heating elements are also provided on the outside of the corundum reactor.

[0019] Furthermore, the heating element is a silicon molybdenum rod (a silicon molybdenum rod resistive heating element).

[0020] Furthermore, the collection device terminal is provided with a porous plate resistor, which is used to hold the product.

[0021] Furthermore, the end of the air inlet pipe is located below the liquid surface of the reactants in the liquid vaporization device, and the end of the air inlet pipe is connected to an aeration head; the vaporization conveying pipe is placed above the liquid surface of the reactants in the liquid vaporization device.

[0022] Furthermore, the product collection device is also connected to a tail gas inlet waste gas treatment device.

[0023] This application also provides a method for preparing single-walled carbon nanotubes from a composition for synthesizing single-walled carbon nanotubes, the preparation steps of which include:

[0024] (1) Weigh the formulation composition according to the proportion and mix it evenly;

[0025] (2) Place the formulation composition prepared by the method in step (1) into a liquid vaporization device. The temperature inside the liquid vaporization device is set to 200-350°C. Adjust the supply amount of the formulation mixture according to the temperature of the vaporization device and the amount of gas introduced (V1).

[0026] (3) The synthesis temperature range is set at 1300℃~1600℃. After the temperature is constant, inert gas (V2) is introduced to purge the air. Then, the liquid vaporization device is turned on to introduce gas (V1) for reaction. The amount of inert gas (V2) is adjusted to control the total gas flow rate to 0.5~2L / min.

[0027] (4) The other end of the floating catalytic cracking reactor is connected to a product collection device to collect products and treat waste gas.

[0028] Furthermore, the inert gas mentioned in step (3) of this application is argon, nitrogen, or a mixture of the two.

[0029] The carbon nanotubes synthesized by the above method in this application are large-diameter single-walled carbon nanotubes with a length >30 μm, a diameter of 2–3.5 nm, and a purity >70%. D / IG <0.2, yields reach 2-10 g / h in a reactor with an inner diameter of 70 mm.

[0030] The advantages and beneficial effects of this application are as follows:

[0031] 1. The formulation composition used in this application for preparing single-walled carbon nanotubes has a boiling point of 150℃ to 300℃, which can prolong the vaporization window time during the floating pyrolysis process; moreover, all components are non-hazardous chemicals and are general chemicals, which greatly improves the safety of the floating catalytic pyrolysis reaction; in addition, the components also contain a certain amount of oxygen atoms (molar fraction of about 0.02% to 0.08%), which decompose under high temperature conditions to form O free radicals and OH free radicals, which can react with the amorphous carbon that has not participated in the reaction in the system and be vaporized and discharged, thereby improving the purity of the product.

[0032] 2. The C used as a carbon source in this application n H 2n+2 The alkanes have a carbon number n of 9 ≤ n ≤ 16, a molecular weight of 128–226 g / mol, a boiling point > 150 °C, and a flash point ≥ 31 °C. Too high or too low a carbon number in the alkanes is detrimental to the synthesis of single-walled carbon nanotubes in this formulation. This is because when the carbon number is below 9, the flash point of the alkanes is only 13 °C, and the boiling point is as low as 120 °C. The window temperature for the high-temperature gasification and cracking process is lower than that of other components, resulting in insufficient participation of the components in the reaction and a low yield. Conversely, when the carbon number is above 16, the boiling point is above 300 °C, and the fluidity of the formulation is reduced, which is unfavorable for the floating catalytic cracking reaction. The carbon number of the alkanes specified in this application can effectively solve the above technical problems.

[0033] 3. The formulation composition for synthesizing single-walled carbon nanotubes in this application, compared with the traditional floating catalytic cracking formulation composition, uses a general chemical with a high flash point and high boiling point as the carbon source and an inert atmosphere as the carrier gas, thereby greatly improving the safety of production. At the same time, the vaporization point of each component in the formulation is greater than 150°C, which makes the components highly synchronous in floating catalytic cracking, thereby increasing the conversion efficiency between components and improving the yield of single-walled carbon nanotubes to a certain extent. The scheme of this application greatly improves the production safety of traditional floating catalytic cracking method, and the raw material cost is low. At the same time, the production process is stable and controllable, and the yield is high, making it suitable for large-scale production.

[0034] 4. This invention is the first to use alkanes with a carbon number n of 9 ≤ n ≤ 16 as the carbon source, combined with other components to form a novel formulation composition for single-walled carbon nanotubes. All components in this composition are high-boiling-point compounds, with boiling points all above 150°C. This avoids the problem of a narrow synthesis window caused by inconsistent volatilization rates between low-boiling-point carbon sources, promoters, and organic transition metal catalysts in traditional floating catalytic cracking technologies. In particular, the high-boiling-point sulfur-containing promoter dimethyl sulfoxide in this formulation composition improves the low-boiling-point volatilization problem of the traditional sulfur-containing promoter thiophene, greatly increasing the cycle time of each component in the high-temperature cracking, melting, and precipitation processes, and improving the yield of single-walled carbon nanotubes. Simultaneously, the high-carbon-number alkane components in this formulation composition can significantly increase the solubility of the catalyst in the system, improving the problem of low conversion rates caused by excess carbon atoms in the system in traditional formulations. The oxygen element in the polyol can react with ineffective carbon-containing free radicals during the cracking process to form gaseous products, improving the purity of the products.

[0035] 5. The components of the formulation composition of the present invention have advantages such as high boiling point, high flash point, and non-flammability. Most of them are general chemicals, non-toxic and odorless, which greatly improves the safety factor in the production process. This is of great significance for promoting the industrialization of the traditional floating catalytic cracking method for preparing single-walled carbon nanotubes.

[0036] 6. This application uses inert gases throughout the reaction process, eliminating the need for hydrogen, which effectively improves reaction safety and product purity. This is because the O atoms in the C2-C3 polyols used in the composition of this application decompose under high temperature conditions to form O and OH free radicals, which react with the CH free radicals that are not dissolved and deposited during the decomposition process, forming gaseous products that are discharged, thereby greatly improving product purity. At the same time, the CnH2n+2 alkane forms H free radicals during the decomposition process, which can inhibit the growth rate of catalyst particles and thus control the diameter distribution of single-walled carbon nanotubes.

[0037] 7. In this application, an aeration head is provided at the end of the inert gas inlet pipe in the liquid vaporization device. The structure of the aeration head can play the role of mixing the formulation composition, so that the components in the formulation are mixed more thoroughly, and can evenly disperse the carrier gas into multiple micro bubbles, so that the heated liquid can be better carried into the reaction chamber by the carrier gas. Attached Figure Description

[0038] Figure 1 This is a flow chart (structural diagram) of the reaction apparatus used in the implementation scheme of this application.

[0039] Figure 2 This is a photograph of the single-walled carbon nanotubes prepared in Example 2 of this application.

[0040] Figure 3 This is a TEM image of a single-walled carbon nanotube prepared in Example 2 of this application.

[0041] Figure 4 The Raman spectrum of the single-walled carbon nanotubes prepared in Example 2 of this application.

[0042] As shown in the attached diagram, 1-liquid gasification device; 11-gasification device heating unit; 12-aeration head; 13-liquid gasification device inlet pipe; 14-liquid gasification device outlet pipe; 2-floating catalytic cracking reactor; 21-reactor inlet pipe; 22-corundum reactor; 23-reactor heating unit; 3-collection device; 31-perforated plate; 32-vacuum pump. Detailed Implementation

[0043] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are merely preferred embodiments, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this invention.

[0044] Furthermore, it should be noted that the descriptions relating to the structural device portion of this application are as follows: when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may be another intermediate component, through which it is fixed. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or there may be another intermediate component present. When a component is referred to as being "set on" another component, it can be directly set on the other component or there may be another intermediate component present. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] As attached Figure 1The diagram shows an apparatus for preparing single-walled carbon nanotubes according to this application. The apparatus includes a liquid vaporization device 1, a floating catalytic cracking reactor 2, and a product collection device 3. The liquid vaporization device 1 is provided with an inlet pipe 13 and a vaporization conveying pipe 14. The inlet pipe 13 is used for gas introduction, and its end extends into the liquid vaporization device 1 and below the liquid surface of the liquid material therein. The vaporization conveying pipe 14 is connected to the floating catalytic cracking reactor 2, which is also connected to an inert gas inlet pipe 21. The product collection device 3 is connected to the outlet end of the floating catalytic cracking reactor 2.

[0046] As an example, more specific examples are attached. Figure 1 As shown, the liquid vaporization device 1 described in this application is a closed bubbling device. Its inlet pipe 13 is connected to an aeration head 12 at its end. One end of the vaporization conveying pipe 14 (i.e., the feed end located inside the liquid vaporization device) is positioned above the liquid surface of the internal reactants to facilitate the input of the vaporized reactants into the subsequent reactor. The liquid vaporization device 1 also includes a heating device 11, which can be a heating device covering the outer wall of the liquid vaporization device (this heating device can use resistance wire heating, combined with thermocouples and PLC temperature control, etc.) to heat and vaporize the reactants, ensuring that the internal heating temperature is not lower than 200℃. The vaporization conveying pipe 14 is connected to the inlet flange of the floating catalytic cracking reactor 2. The intermediate pipes of the floating catalytic cracking reactor 2 are insulated, such as by wrapping with insulation material. To maintain a constant internal reaction temperature; the furnace tube of the floating catalytic cracking reactor 2 can be a corundum reactor 22, the inner diameter of which is 30mm to 150mm, and the length of the constant temperature zone of which is not less than 300mm; a heating element 23 is provided on the outside of the corundum reactor 2, which can be a silicon molybdenum rod, etc., to achieve the heating operation of the reactor; the outlet flange of the floating catalytic cracking reactor 2 is connected to the product collection device 3, and the tail gas is simultaneously connected to the collection device 3. The end of the collection device 3 is provided with a perforated plate 31 (i.e., a partition structure with several through holes, with a certain gap between it and the inner bottom surface of the collection device) for placing the product, and the through holes on it can ensure the passage of tail gas. The tail gas is connected to the suction pump 32 of the collection device 3 for exhausting the tail gas.

[0047] Specifically, the method for preparing single-walled carbon nanotubes using the aforementioned apparatus is as follows:

[0048] (1) Weigh and mix each component of the formulation composition according to the formulation ratio, and then place it in the liquid vaporization device 1. The reaction temperature in the liquid vaporization device 1 is set to 200-350°C. The amount of the formulation mixture supplied to the subsequent floating catalytic cracking reactor 2 can be adjusted according to the temperature inside the liquid vaporization device 1 and the amount of gas introduced (V1).

[0049] (2) The synthesis temperature in the floating catalytic cracking reactor 2 is set at 1300℃~1600℃. After the temperature is constant, inert gas (V2) is introduced to vent the air. Then, the gas inlet (V1) of the liquid gasification device 1 is opened to carry out the reaction. The gas outlet pipe of the liquid gasification device introduces the gasified material into the reactor and adjusts the amount of inert gas (V2) to control the total gas flow rate to 0.5~2L / min. The product is collected by the collection device 3 at the end and the tail gas is treated (specifically, a vacuum pump 32 is set to extract and discharge the tail gas).

[0050] The following are specific examples of preparing single-walled carbon nanotubes:

[0051] Example 1

[0052] (1) Preparation of the formulation solution: Weigh out hexadecane (C 16 H 34 90g, propylene glycol 10g, ferrocene 5g, dimethyl sulfoxide 1g, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0053] (2) Place the liquid formulation composition described in step (1) into the liquid vaporization device 1. Set the temperature of the liquid vaporization device 1 to 300°C. Introduce 0.5 L / min of argon gas (V1) into the liquid vaporization device and introduce 1 L / min of argon gas into the V2 pipe. Control the total gas flow rate to 1.5 L / min. Blow the formulation composition into the high-temperature tubular furnace cavity of the floating catalytic cracking reactor 2 (which can be a corundum reactor tube with a diameter of 70 mm, a temperature of 1400°C, and a heating zone length of 30 cm) for catalytic cracking reaction.

[0054] (3) The other end of the tubular furnace is connected to product collection device 3 to collect the product; the yield of the collected product is 5.7 g / h, the purity of the TGA test is 79%, and the purity of the coarse powder is 1. D / I G It is 0.15.

[0055] Example 2

[0056] (1) Preparation of the formulation solution: Weigh nonane (C9H) 20 90g, 10g ethylene glycol, 5g ferrocene, 1g dimethyl sulfoxide, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0057] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 0.5L / min of argon gas (V1) is introduced into the gasification device, and 1L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0058] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (5.9 g / h, TGA test purity 85%, coarse powder Raman test I). D / I G (0.13);

[0059] The morphology and structure of the product prepared in Example 2 were analyzed, as shown in the attached figure. Figure 2 The single-walled carbon nanotube product shown is black and fibrous, lightweight and sticky; attached Figure 3 TEM characterization of the product revealed a large amount of tube aggregation, smooth tube wall edges, and very few byproducts such as amorphous carbon, indicating high product purity. Figure 4 The product was characterized by Raman spectroscopy, showing a strong G peak near 1560 cm⁻¹ and a defect D peak at 1330 cm⁻¹. D / I G The value is 0.13; in the low wavenumber region (100–250 cm⁻¹), a typical single-walled carbon nanotube breathing vibration peak (RBM peak) appears, with a peak position of 104 cm⁻¹. The peak position frequency shift of single-walled carbon nanotubes is inversely proportional to their diameter, according to d = 248 / ω. RBM It can be seen that the diameter of a single-walled carbon nanotube is 2.38 nm.

[0060] Example 3

[0061] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 95g, glycerol 5g, ferrocene 5g, dimethyl sulfoxide 1g, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0062] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 0.5L / min of argon gas (V1) is introduced into the gasification device, and 1L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0063] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (7.9 g / h, TGA test purity 73%, coarse powder Raman test I).D / I G (0.19).

[0064] Example 4

[0065] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 80g, glycerol 20g, ferrocene 5g, dimethyl sulfoxide 1g, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0066] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 0.5L / min of argon gas (V1) is introduced into the gasification device, and 1L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0067] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (4.3 g / h, TGA test purity 86%, coarse powder Raman test I). D / I G (0.07).

[0068] Example 5

[0069] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 Mix 80g of glycerol, 20g of ferrocene, 0.5g of dimethyl sulfoxide, and 1g of dimethyl sulfoxide evenly, and place in an ultrasonic cleaner to dissolve by shaking.

[0070] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 0.5L / min of argon gas (V1) is introduced into the gasification device, and 1L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0071] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (2.1 g / h, TGA test purity 71%, coarse powder Raman test I). D / I G (0.2).

[0072] Example 6

[0073] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 2280g, glycerol 20g, ferrocene 10g, dimethyl sulfoxide 1g, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0074] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 0.5L / min of argon gas (V1) is introduced into the gasification device, and 1L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0075] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (6.9 g / h, TGA test purity 73%, coarse powder Raman test I). D / I G (0.18).

[0076] Example 7

[0077] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 Mix 80g of glycerol, 20g of ferrocene, 5g of dimethyl sulfoxide, and 0.1g of dimethyl sulfoxide evenly and dissolve by shaking in an ultrasonic cleaner.

[0078] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 0.5L / min of argon gas (V1) is introduced into the gasification device, and 1L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0079] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (2.1 g / h, TGA test purity 72%, coarse powder Raman test I). D / I G (0.12).

[0080] Example 8

[0081] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 Mix 80g of glycerol, 20g of ferrocene, 5g of dimethyl sulfoxide, and 1.5g of dimethyl sulfoxide evenly and dissolve by shaking in an ultrasonic cleaner.

[0082] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 0.5L / min of argon gas (V1) is introduced into the gasification device, and 1L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0083] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (7.8 g / h, TGA test purity 74%, coarse powder Raman test I). D / I G (0.17).

[0084] Example 9

[0085] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 80g, glycerol 20g, ferrocene 5g, dimethyl sulfoxide 1g, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0086] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 1.0L / min of argon gas (V1) is introduced into the gasification device, and 0.5L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0087] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (7.3 g / h, TGA test purity 79%, coarse powder Raman test I). D / I G (0.15).

[0088] Example 10

[0089] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 80g, glycerol 20g, cobalt 5g, dimethyl sulfoxide 1g, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0090] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 1.0L / min of argon gas (V1) is introduced into the gasification device, and 0.5L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner diameter 70mm, temperature 1400°C, heating zone length 30cm) for catalytic cracking reaction.

[0091] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (7.2 g / h, TGA test purity 78%, coarse powder Raman test I). D / I G (0.13).

[0092] Example 11

[0093] (1) Preparation of the formulation solution: Weigh out n-decane (C 10 H 22 80g, glycerol 20g, ferrocene 5g, dimethyl sulfoxide 1g, mix well and place in an ultrasonic cleaner to dissolve by shaking;

[0094] (2) The liquid of the formulation composition is placed in a gasification device, the temperature of the gasification device is set to 300°C, 1.0L / min of argon gas (V1) is introduced into the gasification device, and 0.5L / min of argon gas is introduced into the V2 pipe. The total gas flow rate is controlled to be 1.5L / min. The formulation composition is blown into the high-temperature tubular furnace cavity (inner tube diameter 70mm, temperature 1600°C, heating zone length 30cm) for catalytic cracking reaction.

[0095] (3) The other end of the tubular furnace is connected to a product collection device to collect the product (8.4 g / h, TGA test purity 79%, coarse powder Raman test I). D / I G (0.12).

[0096] Comparative Example 1

[0097] Same as Example 4, except that n-hexane is used instead of n-decane.

[0098] Results: The yield of single-walled carbon nanotubes was 0.8 g / h, the purity was 79% as determined by TGA, and the Raman spectroscopy result was [missing information]. D / I G It is 0.11.

[0099] Comparative Example 2

[0100] Same as Example 4, except that ethanol is used instead of glycerol.

[0101] Results: The yield of single-walled carbon nanotubes was 1.2 g / h, the purity was 68% as determined by TGA, and the Raman spectroscopy result was [missing information]. D / I G It is 0.21.

[0102] Comparative Example 3

[0103] Same as Example 4, except that thiophene is used instead of dimethyl sulfoxide.

[0104] Results: The yield of single-walled carbon nanotubes was 0.6 g / h, the purity was 79% as determined by TGA, and the Raman spectroscopy result was [missing information]. D / I G It is 0.17.

[0105] Comparative Example 4

[0106] Same as Example 4, except that n-decane (C 10 H 22 70g, glycerol 30g.

[0107] Results: The yield of single-walled carbon nanotubes was 1.5 g / h, the purity was 86% as determined by TGA, and the Raman spectroscopy result was [missing information]. D / I G It is 0.15.

[0108] Comparative Example 5

[0109] Same as Example 4, except that n-decane (C 10 H 22 100g, 0g glycerol.

[0110] Result: A large amount of black smoke was produced, but no obvious products were formed.

[0111] Comparative Example 6

[0112] Similar to Example 4, except that a peristaltic pump is used to pump the formulation composition into the reactor tube, and argon gas with the same total gas volume as in Example 4 is introduced.

[0113] Results: The yield of single-walled carbon nanotubes was 0.3 g / h, the purity was 51% as determined by TGA, and the Raman spectroscopy result was [missing information]. D / I G It is 0.51.

[0114] Comparative Example 7

[0115] Same as Example 4, except that the vaporization temperature is set to 150°C.

[0116] Result: A large amount of black smoke was produced, but no obvious products were formed.

[0117] Comparative Example 8

[0118] Same as Example 4, except that the vaporization temperature is set to 400°C.

[0119] Result: A large number of multi-walled tubes were produced.

[0120] Comparative Example 9

[0121] Similar to Example 4, except that 0.5 L / min of argon gas (V1) is introduced into the vaporization device, and 2.5 L / min of argon gas is introduced into the V2 pipe, controlling the total gas flow rate to 3 L / min.

[0122] Results: The yield of single-walled carbon nanotubes was 0.47 g / h, the purity was 63% as determined by TGA, and the Raman spectroscopy result was [missing information]. D / I G It is 0.42.

[0123] Comparative Example 10

[0124] Similar to Example 4, except that argon gas (V1) at a flow rate of 2.5 L / min is introduced into the vaporization device, and argon gas at a flow rate of 1 L / min is introduced into the V2 pipe, controlling the total gas flow rate to be 3 L / min.

[0125] Result: A large number of multi-walled tubes were produced.

[0126] Comparative Example 11

[0127] Same as Example 4, except that the furnace tube temperature was set to 1200℃; Results: single-walled carbon nanotube yield was 0.39 g / h, TGA purity was 51%, and Raman ID / IG ratio was 0.58.

[0128] The results of Examples 1 to 11 show that C9 to C16 alkanes and C2 and C3 polyols can synthesize single-walled carbon nanotubes with high yields and purity within the ratio ranges set in this application. Examples 1 and 2 show that the number of carbon atoms in alkanes has little effect on the yield, while the C / O atomic ratio of polyols has a certain impact on purity. Compared with propylene glycol, ethylene glycol is more conducive to the synthesis of high-purity single-walled carbon nanotubes. Example 3 shows that as the amount of alkanes increases and the amount of polyols decreases, the yield of single-walled carbon nanotubes also increases, but the purity decreases at the same time. Examples 4, 5, and 6 show that the yield of single-walled carbon nanotubes increases with the increase of catalyst, while in Examples 7 and 8, the amount of dimethyl sulfoxide added also has a significant impact on the yield. Example 9, based on Example 8, adjusts the gas flow rate of the liquid vaporizer while keeping the total gas flow rate constant, and the yield is improved. Examples 9 and 10 show that the transition metal catalysts ferrocene and cobalt dicene have basically no effect on the yield of the formulation. Compared with Example 9, Example 11 increases the reaction temperature, and the yield increases from 7.2 g / h to 8.4 g / h.

[0129] Compared to Example 4, Comparative Examples 1-3 replaced the alkanes, polyols, and promoters in the original formulation with low-boiling-point small molecules, resulting in a significant decrease in yield. This is because the volatilization rates of low-boiling-point small molecules in the liquid vaporizer are inconsistent, leading to a narrow optimal synthesis window during floating catalytic cracking and consequently a lower yield of single-walled carbon nanotubes. Comparative Example 4, compared to Example 4, increased the amount of polyol, increasing the relative oxygen content in the system. This resulted in more carbon-containing free radicals reacting with the polyol during cracking to form byproducts, further reducing the yield. Comparative Example 5, compared to Example 4, increased the amount of alkane, with amorphous carbon as the main byproduct.

[0130] As shown in the results of Example 4 and Comparative Example 1, the carbon nanomaterial alcohol solution significantly improves the yield of the floating catalytic cracking method, increasing from 0.8 g / h to 4.3 g / h under the same conditions. Examples 3 and 4 show that the yield increases significantly with increasing carbon nanomaterial concentration, from 4.3 g / h to 9.4 g / h. Meanwhile, high-temperature ultrasonic technology significantly affects the dissolution of the catalyst precursor; compared to Comparative Example 3, the yield in Example 5 increased from 1.9 g / h to 4.8 g / h. Comparative Examples 6-11, with the same formulation composition but different process conditions compared to Example 4, all yielded significantly different results. Comparative Example 6, which directly injected the formulation composition into the reaction chamber using a traditional floating catalytic cracking method, did not yield a good product. This is because the formulation composition of this invention has a relatively high boiling point, and the rapid injection process cannot fully vaporize the components in the formulation composition to form optimal reaction conditions. In Comparative Example 7, the vaporization temperature was as low as 150℃, resulting in incomplete vaporization and volatilization of some components, leading to a low yield. Conversely, when the vaporization temperature was too high (Comparative Example 8), the concentration of reactants entering the reaction chamber was too high, causing changes in product morphology and the formation of multi-walled carbon nanotubes. Comparative Example 9 increased the amount of auxiliary inert gas compared to Comparative Example 4, resulting in an excessively large total gas volume. This led to insufficient time for dynamic processes such as component cracking, catalyst melting, collision, and melt-precipitation, resulting in a low yield. Comparative Example 10 increased the liquid vaporization gas flow, increasing the total gas flow and allowing a large amount of carbon source to rapidly enter the reaction chamber, forming multi-walled carbon nanotubes. The reaction temperature also significantly affected this formulation system. In traditional low-boiling-point formulations, the synthesis temperature of single-walled carbon nanotubes during floating catalytic cracking synthesis is generally 1000–1300℃. However, because this formulation system primarily uses high-boiling-point solvents, the cracking of long carbon chains into highly reactive carbon-containing free radicals requires even higher temperatures. Therefore, when the temperature dropped to 1200℃, the yield decreased sharply.

[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the principles and spirit of the present invention are included within the protection scope of the present invention.

Claims

1. A method of preparing single-walled carbon nanotubes, characterized by: The preparation steps include: (1) proportionally weigh and mix the formula composition; (2) place the formula composition prepared in step (1) in a liquid gasification device, set the temperature in the liquid gasification device to 200-350℃, and adjust the formula mixture supply amount according to the gasification device temperature and the amount of gas introduced; (3) set the synthesis temperature range to 1300-1600℃, after the temperature is constant, introduce inert gas to empty, then open the liquid gasification device gas inlet reaction, and adjust the amount of inert gas to control the total gas flow to be 0.5-2 L / min; (4) connect the other end of the floating catalytic cracking reactor to a product collection device to collect the product, and treat the waste gas; The components of the formula composition in step (1) above include: C n H 2n＋2 80~95 parts by weight; C2-C3 polyhydric alcohol 5-20 parts by weight; Organic transition metal catalyst 0.5-10 parts by weight; Promoter 0.1-1.5 parts by weight; Wherein n is an integer of 9-16; The C2-C3 polyhydric alcohol is at least one of ethylene glycol, propylene glycol, and glycerol; the promoter is dimethyl sulfoxide, and the boiling point is 189℃.

2. The method of claim 1, wherein: The C n H 2n+2 The alkanes have a molecular weight of 128-226 g / mol, a boiling point > 150°C and a flash point > 31°C.

3. The method of claim 2, wherein: The C2-C3 polyhydric alcohol is ethylene glycol, glycerol, or a mixture of the two with a C / O atomic ratio of 1 / 1.

4. The method of claim 1, wherein: The organic transition metal catalyst includes one or a combination of several of ferrocene, cobaltocene, and nickelocene, and the sublimation temperature of the catalyst is >100℃.

5. The method of claim 1, wherein: The reaction device used to prepare the single-walled carbon nanotubes includes a liquid gasification device, a floating catalytic cracking reactor, and a product collection device; the liquid gasification device is provided with a gas inlet pipeline and a gasification delivery pipeline, the gas inlet pipeline is used for gas introduction, and the terminal end of the gas inlet pipeline extends into the liquid gasification device; the gasification delivery pipeline is connected to the floating catalytic cracking reactor, and the floating catalytic cracking reactor is further connected to an inert gas inlet pipeline; the discharge end of the floating catalytic cracking reactor is connected to a product collection device.

6. The method of claim 5, wherein: The liquid gasification device is further provided with a heating device to sufficiently heat the gasification device so that the internal heating temperature is not lower than 200℃.

7. The method of claim 5, wherein the single-walled carbon nanotubes are produced by the method comprising: The furnace tube of the floating catalytic cracking reactor is a corundum reactor with an inner diameter of 30-150 mm and a constant temperature zone length of not less than 300 mm; the outer side of the corundum reactor is further provided with a heating element. ​ 8. The method of claim 7, wherein: The heating element is a silicon molybdenum rod.

9. The method of claim 5, wherein: The terminal end of the collection device is provided with a multi-well plate block, which is used to place the product.

10. The method of claim 5, wherein: The terminal end of the gas inlet pipeline is located below the liquid level of the reaction material in the liquid gasification device, and the terminal end of the gas inlet pipeline is connected to an aeration head; the gasification delivery pipeline is located above the liquid level of the reaction material in the liquid gasification device.

11. The method of claim 5, wherein: The product collection device is further connected to a tail gas access waste gas treatment equipment.

12. The method of claim 11, wherein: The inert gas in step (3) is argon, nitrogen, or a mixture of the two; the obtained single-walled carbon nanotubes are large-diameter single-walled carbon nanotubes with a length >30 um, a tube diameter of 2-3.5 nm, a purity >70%, an ID / IG <0.2, and a yield of 2-10 g / h in a 70 mm inner diameter reactor.

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