Method for detecting detergent main agent in gasoline

Abstract

The invention relates to a method for detecting a clearing agent main agent in gasoline, and the method comprises the following steps: carrying out thin-layer chromatography detection on a to-be-detected sample, and determining the composition of the clearing agent main agent in the concentrated to-be-detected sample according to color spot distribution on an obtained thin-layer chromatography plate, wherein the clearing agent main agent comprises one or more of a polyether amine clearing agent, a polyisobutene amine clearing agent and a Mannich base clearing agent; the thin-layer chromatography detection sequentially comprises developing and developing treatment; a developing agent for developing comprises one or more of a developing agent I, a developing agent II and a developing agent III; the developing solvent I is methanol, and the developing solvent II and the developing solvent III comprise one or more of alcohol with the carbon atom number of 1-6, aliphatic hydrocarbon with the carbon atom number of 5-12 and cycloalkane with the carbon atom number of 5-12. According to the method provided by the invention, whether the clearing agent main agent is added into the sample to be detected or not can be rapidly determined, and the type of the clearing agent main agent can be rapidly and accurately detected.

Description

Technical Field

[0001] This disclosure pertains to the field of petrochemical products, specifically relating to a method for detecting detergent main components in gasoline. Background Technology

[0002] In recent years, with rapid economic growth, the number of cars in my country has increased significantly. In 2023, my country had 420 million motor vehicles, including 320 million cars, ranking first in the world. Such a large number of cars consumes a significant amount of gasoline. Incomplete combustion of gasoline in the engine forms hard, sticky carbon deposits, affecting vehicle speed and gasoline combustion efficiency, and causing environmental pollution. Adding detergents to automotive fuel is an effective and practical way to reduce deposits and lower vehicle emissions.

[0003] The effective cleaning components in detergents are oligomers containing amino groups; these compounds are also known as primary agents. Currently, the most common primary agents are divided into three types: polyetheramines (PEA), polyisobutyleneamines (PIBA), and Mannich bases. Polyetheramine gasoline detergents not only effectively control the formation of deposits in the fuel system and intake system but also reduce the formation of combustion chamber carbon deposits (CCD). Polyisobutyleneamine detergents, when added to automotive gasoline, can inhibit the formation of deposits inside the fuel system and rapidly disperse and remove existing oxidized deposits, thus ensuring the normal performance of the car engine. Mannich base detergents, when added to gasoline, not only effectively control the formation of deposits on low-temperature components of the gasoline engine but also effectively remove and inhibit the formation of deposits in high-temperature areas such as intake valves. Unlike gasoline, which is mainly composed of hydrocarbons, these primary agents are high-molecular polymers, with polymer groups primarily consisting of propylene oxide, butane oxide, and isobutylene, and are usually end-capped with polar amino groups, with a molecular weight range of around 1000. It is difficult to analyze it using traditional gas chromatography and gas chromatography-mass spectrometry techniques.

[0004] Currently, the testing methods for detergents include the latest national standard "Automotive Detergents" issued by the State Administration for Market Regulation. This standard stipulates that the main testing method for gasoline detergents is bench testing. However, this method has a long evaluation cycle, high cost, and is difficult to apply in routine gasoline quality testing. Patent ZL200410031504.6 and industry standard HJ2525-2012 use thin-layer chromatography to determine whether gasoline detergents have been added. This method does not develop the color of the main agent; instead, it determines the presence of detergents by directly observing the position of dark spots on the thin-layer plate. However, this method requires pre-concentration of a large amount of gasoline sample, resulting in a long analysis time. Since the detergent main agent is generally colorless or light-colored, this method makes it difficult to observe the position of colorless spots. Furthermore, this method can only be used to identify polyetheramines and polyisobutyleneamine main agents, not Mannich base main agents. Summary of the Invention

[0005] The purpose of this invention is to provide a method for detecting detergent main components in gasoline. The method provided by this invention can quickly determine whether detergent main components have been added to the sample to be tested, and can quickly and accurately detect the type of detergent main components.

[0006] To achieve the above objectives, the present invention provides a method for detecting detergent main components in gasoline, wherein the method includes: Thin-layer chromatography was performed on the sample to be tested, and the composition of the detergent main component in the concentrated sample to be tested was determined based on the distribution of the spots on the obtained thin-layer chromatographic plate. The detergent main component includes one or more of polyetheramine detergents, polyisobutyleneamine detergents, and Mannich base detergents; The thin-layer chromatography detection includes development and color development processes in sequence; The developing agent includes one or more of developing agent I, developing agent II and developing agent III; The developing agent I is methanol; the developing agents II and III include alcohols with 1 to 6 carbon atoms, aliphatic hydrocarbons with 5 to 12 carbon atoms, and cycloalkanes with 5 to 12 carbon atoms.

[0007] Optionally, the developing agent II includes one or more of isopropanol, n-hexane, and isobutanol; the developing agent III includes one or more of methanol, isopropanol, and n-propanol.

[0008] Optionally, the developing agent II is a mixture of isopropanol and n-hexane, or isobutanol; the developing agent III is a mixture of methanol and isopropanol, or n-propanol. The volume ratio of isopropanol to n-hexane is 1:(1~4); the volume ratio of methanol to isopropanol is 1:(2~4). The volume ratio of the developing solvent to the sample to be tested on the thin-layer chromatographic plate is (15~25):1.

[0009] Optionally, the developing solvent is developing solvent I. If the main reagent characteristic points on the thin-layer chromatographic plate obtained after development have colored spots, then the sample to be tested contains a polyetheramine detergent; the main reagent characteristic points are R. f The range of values ​​is 0.5 to 0.7.

[0010] Optionally, the developing solvent is developing solvent II. If the main reagent characteristic points on the thin-layer chromatographic plate obtained after development have colored spots, then the sample to be tested contains a polyisobutylene amine detergent; the main reagent characteristic points are R. f The range of values ​​is 0.3 to 0.4.

[0011] Optionally, the method further includes: The first thin-layer chromatographic plate was developed using developing solvent I, the second thin-layer chromatographic plate was developed using developing solvent II, and the third thin-layer chromatographic plate was developed using developing solvent III. If the origin of the first, second, and third thin-layer chromatographic plates obtained by development has colored spots, then the main detergent for the sample to be tested is a Mannich base detergent.

[0012] Optionally, the method further includes: before performing the thin-layer chromatography detection, using developing solvent A to perform thin-layer chromatography detection on the sample to be tested; the developing solvent A includes ester compounds, preferably fatty lipids, more preferably ethyl acetate; the developing height of the pre-chromatographic detection is greater than the developing height of the thin-layer chromatography detection.

[0013] Optionally, in the colorimetric treatment, the colorimetric agent includes a ninhydrin solution with a concentration of 0.1~10wt%; the solvent of the ninhydrin solution includes water and / or ethanol.

[0014] Optionally, in the thin-layer chromatography, the developing plate is one or more of silica gel, modified silica gel, alumina, and modified alumina.

[0015] Optionally, the method further includes: concentrating gasoline to obtain the sample to be tested; The concentration factor is 20 to 100.

[0016] Through the above technical solution, this invention employs thin-layer chromatography, using developing solvents I, II, and III to develop the sample. Based on the distribution of spots on the resulting thin-layer chromatographic plate, the type of detergent main agent (polyetheramine detergent, polyisobutyleneamine detergent, and Mannich base detergent) can be rapidly and accurately detected. The detection method provided by this invention requires a small sample volume, is rapid and efficient, has good repeatability, high accuracy, and good stability. It does not require sample concentration, exhibits high selectivity, and has a short analysis time for a single sample. It can quickly and accurately determine whether detergent main agents have been added to gasoline, and the type of detergent main agent added.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a display panel diagram of Embodiment 1 of this application.

[0019] Figure 2This is a display panel diagram of Embodiment 2 of this application.

[0020] Figure 3 This is a display panel diagram of Embodiment 2 of this application.

[0021] Figure 4 This is a display panel diagram of Embodiment 2 of this application.

[0022] Figure 5 This is a display panel diagram of Embodiment 2 of this application.

[0023] Figure 6 This is a display panel diagram of Embodiment 3 of this application.

[0024] Figure 7 This is a display panel diagram of Embodiment 4 of this application.

[0025] Figure 8 This is a display panel diagram of Embodiment 5 of this application.

[0026] Figure 9 This is a display panel diagram of Embodiment 6 of this application.

[0027] Figure 10 This is a display panel diagram of Embodiment 7 of this application.

[0028] Figure 11 This is a display panel diagram of Embodiment 8 of this application.

[0029] Figure 12 This is a display panel illustration for Comparative Example 1.

[0030] Figure 13 This is a display panel illustration for Comparative Example 1.

[0031] Figure 14 This is a display panel diagram for Comparative Example 2.

[0032] Figure 15 This is a schematic diagram of the unfolded plates of gasoline samples 1 to 7 provided in this application. Detailed Implementation

[0033] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0034] This disclosure provides a method for detecting detergent main components in gasoline, wherein the method includes: Thin-layer chromatography (TLC) is performed on the sample to be tested. The composition of the detergent main component in the concentrated sample is determined based on the distribution of spots on the obtained TLC plate. The detergent main component includes one or more of polyetheramine detergents, polyisobutyleneamine detergents, and Mannich base detergents. The TLC detection sequentially includes development and colorimetric processing. The developing solvent includes one or more of developing solvent I, developing solvent II, and developing solvent III. Developing solvent I is methanol, and developing solvent II and developing solvent III include alcohols with 1-6 carbon atoms, aliphatic hydrocarbons with 5-12 carbon atoms, and cycloalkanes with 5-12 carbon atoms.

[0035] This disclosure employs thin-layer chromatography (TLC) and uses developing solvents I, II, and III to develop the test sample. Based on the distribution of color spots on the resulting TLC plate, the type of detergent main agent (polyetheramine detergent, polyisobutyleneamine detergent, and Mannich base detergent) can be rapidly and accurately detected. The detection method provided by this disclosure requires a small sample volume, is rapid and efficient, has good repeatability, high accuracy, and good stability. It does not require sample concentration, exhibits high selectivity, and has a short analysis time for a single sample. It can quickly and accurately determine whether detergent main agents have been added to gasoline, and the type of detergent main agent added.

[0036] In one specific embodiment, the polarity of developing agent I is greater than that of developing agent III, which in turn is greater than that of developing agent II.

[0037] In one specific embodiment, the developing agent II comprises one or more of isopropanol, n-hexane, and isobutanol; the developing agent III comprises one or more of methanol, isopropanol, and n-propanol. In a preferred embodiment, the developing agent II is a mixture of isopropanol and n-hexane, or isobutanol; the developing agent III is a mixture of methanol and isopropanol, or n-propanol. In a further preferred embodiment, the developing agent II is a mixture of isopropanol and n-hexane, and the developing agent III is a mixture of methanol and isopropanol; wherein the volume ratio of isopropanol to n-hexane is 1:(1~4), preferably 1:1; and the volume ratio of methanol to isopropanol is 1:(2~4), preferably 1:3. In the above embodiments, by selecting preferred types of developing agents I, II, and III, this disclosure can more effectively and accurately detect the type of detergent main agent, further improving the accuracy of the test results.

[0038] In one specific embodiment, the volume ratio of the developing solvent to the sample to be tested on the thin-layer chromatographic plate is (15~25):1, preferably 20:1.

[0039] In one specific embodiment, the developing solvent is developing solvent I. If the main reagent characteristic points on the thin-layer chromatographic plate obtained after development have colored spots, then the sample to be tested contains a polyetheramine detergent; the main reagent characteristic points are R. f The value is in the range of 0.5 to 0.7; if the main reagent characteristic points of the developed thin-layer chromatogram have no color spots, then the sample to be tested does not contain polyetheramine detergents.

[0040] In one specific embodiment, the developing solvent is developing solvent II. If the main reagent characteristic points on the thin-layer chromatographic plate obtained after development have colored spots, then the sample to be tested contains a polyisobutylene amine detergent; the main reagent characteristic points are R. f The value is in the range of 0.3 to 0.4; if the main reagent characteristic points of the thin-layer chromatogram obtained by development have no color spots, then the sample to be tested does not contain polyisobutylene amine detergents.

[0041] In one specific embodiment, the developing solvent is developing solvent III. If there is a colored spot at the origin of the thin-layer chromatographic plate obtained by development, the sample to be tested contains Mannich base detergent; if there is no colored spot at the origin of the thin-layer chromatographic plate obtained by development, the sample to be tested does not contain Mannich base detergent.

[0042] In one specific embodiment, the method further includes: developing a first thin-layer chromatographic plate with developing solvent I, developing a second thin-layer chromatographic plate with developing solvent II, and developing a third thin-layer chromatographic plate with developing solvent III; if the origins of the first, second, and third thin-layer chromatographic plates obtained by development have colored spots, and the characteristic points of the main agent have no colored spots, then the main detergent of the sample to be tested is a Mannich base detergent.

[0043] In this disclosure, the spots appearing in the thin-layer chromatography plate may include trailing spots and dotted spots.

[0044] In another implementation, such as Figure 15 As shown, the method further includes: developing a first thin-layer chromatographic plate with developing solvent I, developing a second thin-layer chromatographic plate with developing solvent II, and developing a third thin-layer chromatographic plate with developing solvent III; if the main agent characteristic points of the first thin-layer chromatographic plate have colored spots, but the origin has no colored spots; the main agent characteristic points of the second thin-layer chromatographic plate have no colored spots, but the origin has colored spots; and the main agent characteristic points of the third thin-layer chromatographic plate have colored spots, but the origin has no colored spots, then the main detergent in the sample to be tested is a polyetheramine detergent.

[0045] In another implementation, such as Figure 15As shown, the method further includes: developing a first thin-layer chromatographic plate with developing solvent I, developing a second thin-layer chromatographic plate with developing solvent II, and developing a third thin-layer chromatographic plate with developing solvent III; if the main agent characteristic points of the first thin-layer chromatographic plate have no color spots, but the origin has color spots; the main agent characteristic points of the second thin-layer chromatographic plate have color spots, but the origin has no color spots; and the main agent characteristic points of the third thin-layer chromatographic plate have color spots, but the origin has no color spots, then the main detergent in the sample to be tested is a polyisobutylene amine detergent.

[0046] In one specific implementation, such as Figure 15 As shown, the method further includes: developing a first thin-layer chromatographic plate with developing solvent I, developing a second thin-layer chromatographic plate with developing solvent II, and developing a third thin-layer chromatographic plate with developing solvent III; if the main reagent characteristic point and the origin of the first thin-layer chromatographic plate have colored spots respectively; the main reagent characteristic point of the second thin-layer chromatographic plate has colored spots and the origin has colored spots; and the main reagent characteristic point of the third thin-layer chromatographic plate has colored spots but the origin does not have colored spots, then the main detergent in the sample to be tested is a polyetheramine detergent and a polyisobutyleneamine detergent.

[0047] In another specific implementation, such as Figure 15 As shown, the method further includes: developing a first thin-layer chromatographic plate with developing solvent I, developing a second thin-layer chromatographic plate with developing solvent II, and developing a third thin-layer chromatographic plate with developing solvent III; if the main reagent characteristic point and the origin of the first thin-layer chromatographic plate have colored spots respectively; the main reagent characteristic point of the second thin-layer chromatographic plate has no colored spots, but the origin has colored spots; and the main reagent characteristic point and the origin of the third thin-layer chromatographic plate have colored spots respectively, then the main detergent in the sample to be tested is a polyetheramine detergent and a Mannich base detergent.

[0048] In another specific implementation, such as Figure 15 As shown, the method further includes: developing a first thin-layer chromatographic plate with developing solvent I, developing a second thin-layer chromatographic plate with developing solvent II, and developing a third thin-layer chromatographic plate with developing solvent III; if the main reagent characteristic point of the first thin-layer chromatographic plate has no color spot, but the origin has a color spot; the main reagent characteristic point and the origin of the second thin-layer chromatographic plate each have color spots; and the main reagent characteristic point and the origin of the third thin-layer chromatographic plate each have color spots, then the main detergent in the sample to be tested is a polyisobutylene amine detergent and a Mannich base detergent.

[0049] In another specific implementation, such as Figure 15As shown, the method further includes: developing a first thin-layer chromatographic plate with developing solvent I, developing a second thin-layer chromatographic plate with developing solvent II, and developing a third thin-layer chromatographic plate with developing solvent III; if the main reagent characteristic point and origin of the first thin-layer chromatographic plate have colored spots respectively; the main reagent characteristic point and origin of the second thin-layer chromatographic plate have colored spots respectively; and the main reagent characteristic point and origin of the third thin-layer chromatographic plate have colored spots respectively, then the main detergent in the sample to be tested is a polyetheramine detergent, a polyisobutyleneamine detergent, or a Mannich base detergent.

[0050] In one specific embodiment, the method further includes: detecting whether the sample to be tested contains a detergent main agent before performing the thin-layer chromatography detection.

[0051] In a further embodiment, the detection includes: using developing solvent A to perform thin-layer chromatography on the sample to be tested; if there is a colored spot at the origin of the obtained thin-layer chromatographic plate and a colored spot at the pre-chromatographic characteristic point, then the sample to be tested contains a detergent main agent and aniline; the developing solvent A includes ester compounds, preferably fatty esters, more preferably ethyl acetate; the development height of the pre-chromatographic characteristic point is greater than the development height of the main agent characteristic point. In the above embodiment, using developing solvent A can elute aniline in gasoline to the very front of the thin-layer chromatographic plate, effectively preventing its spot color from affecting the determination of the detergent main agent type, thereby further improving the accuracy of detecting the main agent type.

[0052] In one specific embodiment, the colorimetric treatment uses a ninhydrin solution as the colorimetric agent, wherein the concentration of the ninhydrin solution is 0.1-10 wt%, preferably 0.5-1 wt%; the solvent of the ninhydrin solution includes water and / or ethanol, preferably ethanol. In the above embodiment, by selecting a ninhydrin colorimetric agent that responds only to primary and secondary amines but not to tertiary amines and amides, it is beneficial to eliminate the interference of tertiary amine and amide polymers with poor or no cleaning effect on the main cleaning agent.

[0053] In one specific embodiment, the colorimetric treatment conditions include: a treatment temperature of 70-100°C, preferably 80-90°C, and a treatment time of at least 3 minutes, preferably 5-6 minutes. Using the above-mentioned preferred range of embodiments facilitates sufficient contact and reaction between the main agent in the detergent and the ninhydrin colorimetric agent, thereby improving detection accuracy.

[0054] In one specific embodiment, the developing plate in the thin-layer chromatography is one or more of silica gel, modified silica gel, alumina, and modified alumina, preferably silica gel or modified silica gel.

[0055] In one specific embodiment, the method further includes: concentrating gasoline to obtain the sample to be tested; wherein the concentration factor is 20 to 100, preferably 50 to 100.

[0056] In one specific embodiment, the main component of the detergent is a long-chain amine compound, the weight-average molecular weight of which is 500-2500; the long-chain amine compound includes one or more of polyether amine, polyisobutylene amine and Mannich base; the mass fraction of the main component of the detergent in the detergent is 1-100%.

[0057] The present invention will be further illustrated by the following examples, but the invention is not limited thereto. Unless otherwise specified, the reagents used in the examples and comparative examples are commercially available products.

[0058] Example 1 a. Preparation of the sample to be tested: Place a 10mL reagent bottle on an analytical balance, weigh 50mg of polyetheramine (molecular weight 1000, purity 99%), and add n-hexane to 5g to obtain a gasoline solution with a detergent main component content of 10000ppm, which is denoted as sample A to be tested. Place a 10 mL reagent bottle on an analytical balance, weigh 353 mg of G17 (the main agent is polyisobutyleneamine, with a purity of 14.14%), and add n-hexane to 5 g to obtain a gasoline solution with a detergent main agent mass content of 10000 ppm, which is recorded as sample B to be tested. Place a 10 mL reagent bottle on an analytical balance, weigh 57 mg of JGGF23 (main agent is Mannich base, purity 86.43%), and add n-hexane to 5 g to obtain a gasoline solution with a detergent main agent mass content of 10000 ppm, which is recorded as sample C to be tested. Place a 10mL reagent bottle on an analytical balance and weigh 5g of 95-octane gasoline without detergent main agent, and record it as sample D to be tested.

[0059] b. Detection using thin-layer chromatography: (1) Place the thin-layer chromatography silica gel G plate (50×100mm, coating thickness 0.2~0.25mm) in an oven at 110˚C for half an hour to activate it, and then put it in a desiccator for later use; (2) Pour the developing solvent A into the double-barrel thin-layer chromatography developing tank, cover and seal it, and let it stand for more than half an hour to make it saturated; the developing solvent A is ethyl acetate; (3) Mark the development front with a pencil 2 cm away from the bottom of the thin-layer chromatography silica gel plate. Then spot the test sample A, test sample B, test sample C and test sample D on the same silica gel plate. The sample volume is 5 μL. Place the silica gel plate in the developing tank and develop for about 4 cm. Then take it out and let it dry. (4) Spray an ethanol solution containing 0.5 wt% ninhydrin onto a silicone plate until the humidity of the silicone plate is 30% RH, then place it in a 120˚C oven and heat for 10 min, and inspect it immediately.

[0060] The results are as follows Figure 1 As shown, under the action of ethyl acetate as the developing solvent, the sample D developed the farthest distance, R. f The values ​​were 0.8 to 0.9, while the test samples A, B, and C did not move, indicating that aniline was effectively distinguished from the three main detergents. Furthermore, under the action of the color-developing agent ninhydrin solution, the spots of aniline and the three main detergents turned purplish-red, showing obvious color development.

[0061] Therefore, the results of Example 1 show that ethyl acetate can effectively separate small-molecule nitrogen-containing aniline compounds from the detergent main component in gasoline.

[0062] Example 2 a. Preparation of the sample to be tested: Place a 10mL reagent bottle on an analytical balance, weigh 50mg of polyetheramine (molecular weight 1000, purity 99%), and add n-hexane to 5g to obtain a gasoline solution with a detergent main component content of 10000ppm, which is denoted as sample A'. Place a 10 mL reagent bottle on an analytical balance, weigh 353 mg of G17 (the main agent is polyisobutylene amine, with a purity of 14.14%), and add n-hexane to 5 g to obtain a gasoline solution with a detergent main agent mass content of 10000 ppm, which is denoted as the test sample B'. Place a 10 mL reagent bottle on an analytical balance, weigh 57 mg of JGGF23 (main agent is Mannich base, purity 86.43%), and add n-hexane to 5 g to obtain a gasoline solution with a detergent main agent mass content of 10000 ppm, which is denoted as the test sample C'. b. Detection using thin-layer chromatography: (1) Place the thin-layer chromatography silica gel G plate (50×100 mm, coating thickness 0.2~0.25 mm) in an oven at 110˚C for half an hour to activate it, and then put it in a desiccator for later use; (2) Pour the developing solvent I into the double-cell thin-layer chromatography developing tank, cover and seal it, and let it stand for 0.5 hours to saturate it; the developing solvent I is methanol; the volume ratio of developing solvent to sample is 20:1; (3) Mark the development front with a pencil 2 cm away from the bottom of the thin-layer chromatography silica gel plate. Then spot the test sample A', test sample B' and test sample C' onto the thin-layer chromatography plate respectively. The spotting volume is 5 μL for each sample. Place the silica gel plate into the developing tank and develop for about 4 cm. Then take it out and let it dry. (4) Spray an ethanol solution containing 0.5wt% ninhydrin onto the silicone plate until the humidity of the silicone plate is 30%rh. Use a hair dryer on the hot setting (60~70˚C) to heat the silicone plate for 1 minute and then inspect it.

[0063] Take three more silicone plates of the same size and replace the developing agent I in step (2) with isopropanol and n-hexane in a volume ratio of 1:1 (developing agent II), propanol (developing agent III), and a mixture of methanol and isopropanol in a volume ratio of 1:3 (developing agent III) according to the above method. The rest of the steps are the same.

[0064] The results are as follows Figure 2 As shown, when the developing solvent is methanol, the developing distance of sample A' is the farthest, R f The value is 0.6, and neither sample B' nor sample C' showed any movement. This indicates that sample A' contains polyetheramine detergent main components, while samples B' and C' do not. The results are as follows: Figure 3 As shown, when the volume ratio of isopropanol to n-hexane as the developing solvent is 1:1, the developing distance of sample B' is the farthest. f A value of 0.3 indicates that sample A' shows a discolored spot at the spotting origin, while sample C' does not move. This suggests that sample B' contains polyisobutylene amine detergent main components, while samples A' and C' do not contain polyisobutylene amine detergent main components. The results are as follows: Figure 4 As shown, when the developing solvent is n-propanol, the developing distance of sample B' is the farthest. Among them, the developing distance of sample A' is R. f The value is 0.3, and the R of the test sample B' is... f The value is 0.4, and since sample C' did not move, it indicates that sample C' contains Mannich base detergent main components, while samples A' and B' do not contain Mannich base detergent main components; the results are as follows. Figure 5 As shown, when the volume ratio of methanol to isopropanol as the developing solvent is 1:3, the developing distances of test samples A' and B' are the farthest. Among them, the R of test sample A' is the longest. f The value is 0.6, and the R value of the sample B' is... f If the value is 0.6 and the sample C' did not move, it indicates that the sample C' contains Mannich base detergent main agent, while the samples A' and B' do not contain Mannich base detergent main agent.

[0065] Therefore, the method provided in this application can quickly and accurately determine that the sample A' contains only polyetheramine detergent main agent, the sample B' contains only polyisobutyleneamine detergent main agent, and the sample C' contains only Mannich base detergent main agent.

[0066] Example 3 a. Preparation of concentrated test samples: Add 0.1g of polyisobutyleneamine (PIBA) detergent (molecular weight 1000) to 1kg of 95-octane gasoline to obtain a test sample with a detergent main content of 100ppm; then place 10mL of the above test sample in a concentrator to concentrate to 100μL to obtain a concentrated test sample.

[0067] b. Detection using thin-layer chromatography: (1) Place the thin-layer chromatography silica gel G plate (50×100mm, coating thickness 0.2~0.25mm) in an oven at 110˚C for half an hour to activate it, and then put it in a desiccator for later use; (2) Mark the bottom edge of the thin-layer silica gel plate with a pencil 2 cm away as the development front. Spot the concentrated sample to be tested on the marked line of the silica gel plate with a sample volume of 5 μL. (3) Pour the developing solvent A into the double-cell thin-layer chromatography developing tank, cover and seal it to saturate it, put the silica gel plate into the developing tank, and carry out the first development. After developing for about 5 cm, take it out and let it dry. The developing solvent A is ethyl acetate. (4) Pour the developing solvent I (methanol) into the double-cell thin-layer chromatography developing tank, cover and seal it to saturate the developing tank, then put the silica gel plate into the developing tank for a second development. After developing about 4 cm, take it out and let it dry. (5) Spray an ethanol solution containing 0.5wt% ninhydrin onto the silicone plate until the humidity of the silicone plate is 30%rh. Use a hair dryer on the hot setting (60~70˚C) to heat the silicone plate for 1 minute and then inspect it.

[0068] Take two more silicone plates of the same specifications and use the above method to replace the developing agent A in step (4) with developing agent II (volume ratio of isopropanol to n-hexane is 1:1) and developing agent III (volume ratio of methanol to isopropanol is 1:3), respectively. The rest of the steps are the same.

[0069] like Figure 6 As shown in (a), during the second development using developing solvent I, the pre-chromatographic characteristic points on the thin-layer chromatographic plate showed colored spots, while the main reagent characteristic points did not show colored spots, and the origin showed colored spots, indicating that the sample to be tested does not contain polyetheramine detergent main agents. Figure 6 As shown in (b), during the second development using developing solvent II, the pre-chromatographic characteristic points and the main reagent characteristic points of the thin-layer chromatographic plate showed colored spots, while the origin showed no colored spots, indicating that the sample contained a polyisobutylene amine detergent main agent. Figure 6As shown in (c), when the second development was performed using developing solvent III, the pre-chromatographic characteristic points of the thin-layer plate showed colored spots, the main solvent characteristic points showed colored spots, and the origin showed no colored spots, indicating that the gasoline did not contain Mannich base detergent main solvent.

[0070] Therefore, the method provided in this disclosure can quickly and accurately determine that the sample to be tested contains only PIBA.

[0071] Example 4 a. Preparation of concentrated test samples: Add 0.1g of polyetheramine main agent (molecular weight approximately 1000) and 0.1g of Mannich base main agent (molecular weight approximately 1000) to 1kg of 95-octane gasoline to obtain a test sample with a detergent compound content of 200ppm; place 10mL of the above test sample in a concentrator and concentrate to 100μL to obtain a concentrated test sample.

[0072] (1) Place the thin silicone sheet (50×100mm, coating thickness 0.2~0.25mm) in an oven at 110˚C for half an hour to activate it, and then place it in a desiccator for later use; (2) Mark the bottom edge of the thin-layer silica gel plate with a pencil 2 cm away as the development front. Spot the concentrated sample to be tested on the marked line of the silica gel plate with a sample volume of 5 μL. (3) Pour the developing solvent A into the double-cell thin-layer chromatography developing tank, cover and seal it, and let it stand for at least half an hour to saturate it; perform the first development, and after developing about 5 cm, take it out and let it dry; the developing solvent A is ethyl acetate; (4) Pour the developing solvent I (methanol) into the double-cell thin-layer chromatography developing tank, cover and seal it to saturate the developing tank, then put the silica gel plate into the developing tank for a second development. After developing about 4 cm, take it out and let it dry. (5) Spray an ethanol solution containing 0.5wt% ninhydrin onto the silicone plate until the humidity of the silicone plate is 30%rh. Use a hair dryer on the hot setting (60~70˚C) to heat the silicone plate for 1 minute and then inspect it.

[0073] Take two more silicone plates of the same specifications and use the above method to replace the developing agent A in step (4) with developing agent II (volume ratio of isopropanol to n-hexane is 1:1) and developing agent III (volume ratio of methanol to isopropanol is 1:3), respectively. The rest of the steps are the same.

[0074] The results are as follows Figure 7 As shown in (a), during the second development using developing solvent I, colored spots appeared at the pre-chromatographic characteristic points, the main reagent characteristic points, and the origin, indicating that the sample contained a polyetheramine detergent main agent. Figure 7As shown in (b), during the second development using developing solvent II, the pre-chromatographic characteristic points of the thin-layer plate showed colored spots, while the main solvent characteristic points did not show colored spots. The origin showed a colored spot, indicating that the sample to be tested does not contain polyisobutylene amine detergent main solvent. Figure 7 As shown in (c), when the second development was performed using developing solvent III, the pre-chromatographic characteristic points of the thin-layer plate showed colored spots, the main solvent characteristic points showed colored spots, and the origin showed colored spots, indicating that the sample to be tested contained Mannich base detergent main solvent.

[0075] Therefore, the method provided in this disclosure can quickly and accurately determine whether a sample to be tested contains polyetheramine detergent main components or Mannich base detergent main components.

[0076] Example 5 The method of Example 4 was adopted, except that in step a, 0.1g of polyetheramine detergent main agent (molecular weight about 1000) and 0.1g of polyisobutyleneamine main agent (molecular weight about 1000) were added to 1kg of 95 gasoline to obtain a test sample with a detergent compound content of 200ppm.

[0077] The results are as follows Figure 8 As shown in (a), during the second development using developing solvent I, colored spots appeared at the pre-chromatographic characteristic points, the main reagent characteristic points, and the origin, indicating that the sample contained a polyetheramine detergent main agent. Figure 8 As shown in (b), during the second development using developing solvent II, colored spots appeared at the pre-chromatographic characteristic points of the thin-layer plate, colored spots appeared at the main solvent characteristic points, and colored spots also appeared at the origin, indicating that the sample contained polyisobutylene amine detergent as the main solvent. Figure 8 As shown in (c), when the second development was performed using developing solvent III, the pre-chromatographic characteristic points of the thin-layer plate showed colored spots, the main solvent characteristic points showed colored spots, and the origin showed no colored spots, indicating that the sample to be tested did not contain Mannich base detergent main solvent.

[0078] Example 6 The method of Example 4 was adopted, except that in step a, 0.1g of polyisobutylene amine main agent (molecular weight about 1000) and 0.1g of Mannich base detergent main agent (molecular weight about 1000) were added to 1kg of 95 gasoline to obtain a test sample with a detergent compound content of 200ppm.

[0079] The results are as follows Figure 9 As shown in (a), during the second development using developing solvent I, the pre-chromatographic characteristic points on the thin-layer chromatographic plate showed colored spots, while the main reagent characteristic points did not show colored spots, and the origin showed colored spots, indicating that the sample to be tested does not contain polyetheramine detergent main agents. Figure 9As shown in (b), during the second development using developing solvent II, colored spots appeared at the pre-chromatographic characteristic points of the thin-layer plate, colored spots appeared at the main solvent characteristic points, and colored spots also appeared at the origin, indicating that the sample contained polyisobutylene amine detergent as the main solvent. Figure 9 As shown in (c), when the second development was performed using developing solvent III, the pre-chromatographic characteristic points of the thin-layer plate showed colored spots, the main solvent characteristic points showed colored spots, and the origin showed colored spots, indicating that the sample to be tested contained Mannich base detergent main solvent.

[0080] Example 7 The method of Example 2 is adopted, except that the developing agent II in step (2) is replaced with a volume mixture of isopropanol and n-hexane in a volume ratio of 1:5.

[0081] The results are as follows Figure 10 As shown, when the volume ratio of isopropanol to n-hexane as the developing agent is not within the preferred range of this application, the developing distance of the test sample B' is the farthest, but the tailing distance is long, which reduces the accuracy of judging polyisobutyleneamine-type detergents.

[0082] Example 8 The method of Example 2 is adopted, except that the developing agent III in step (2) is replaced with a mixture of methanol and isopropanol in a volume ratio of 1:5.

[0083] The results are as follows Figure 11 As shown, when the volume ratio of methanol to isopropanol as the developing solvent is not within the preferred range of this application, the developing distances of test samples A' and B' are the farthest. Among them, the R of test sample A' is the longest. f The value is 0.5, and the R of the test sample B' is... f The value is 0.5, and the sample C' did not move, but a purplish-red line appeared in the background, which may interfere with the judgment.

[0084] Comparative Example 1 The method of Example 1 and the test samples A, B, C and D were used, the only difference being that the developing solvent A was replaced with n-hexane and ethanol, respectively.

[0085] When the developing solvent A is n-hexane, the results are as follows: Figure 12 As shown, none of the test samples A, B, C, and D moved, indicating that hexane cannot distinguish between aniline-based small-molecule nitrogen compounds and the three detergent main components in gasoline.

[0086] When the developing solvent A is ethanol, the results are as follows: Figure 13As shown, test samples A, B, and D moved with the developing solvent, while test sample C did not move. This indicates that ethanol cannot identify aniline-based small-molecule nitrogen compounds and polyetheramine detergent main agents in gasoline, nor can it identify aniline-based small-molecule nitrogen compounds and polyisobutyleneamine detergent main agents.

[0087] For gasoline containing aniline-type small-molecule nitrogen compounds, the thin-layer chromatography method provided in this disclosure can be used to elute aniline in gasoline to the front of the thin-layer chromatographic plate using developing solvent A. This can effectively prevent the color of the spots from affecting the determination of the detergent main agent type, thereby further improving the accuracy of the determination of the main agent type.

[0088] Comparative Example 2 The method of Example 2 and the test samples A', B' and C' were used, except that the developing agent in step (2) was replaced with ethylene glycol.

[0089] The results are as follows Figure 14 As shown, when the developing solvent is ethylene glycol, none of the test samples A', B', and C' moved, indicating that ethylene glycol cannot distinguish the type of detergent main agent.

[0090] Based on the test results of Examples 1-8 and Comparative Examples 1-2 of this disclosure, it is evident that this disclosure employs thin-layer chromatography, using developing solvents I, II, and III to develop the test sample. Then, based on the distribution of color spots on the resulting thin-layer chromatographic plate, the type of detergent main agent (polyetheramine detergent, polyisobutyleneamine detergent, and Mannich base detergent) can be rapidly and accurately detected. The detection method provided by this disclosure requires a small sample volume, is rapid and efficient, has good repeatability, high accuracy, and good stability. It does not require sample concentration, exhibits high selectivity, and has a short analysis time for a single sample. It can rapidly and accurately determine whether detergent main agents have been added to gasoline, and the type of detergent main agent added.

[0091] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0092] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0093] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for detecting detergent main components in gasoline, wherein, The method includes: Thin-layer chromatography was performed on the sample to be tested, and the composition of the detergent main component in the concentrated sample to be tested was determined based on the distribution of the spots on the obtained thin-layer chromatographic plate. The detergent main component includes one or more of polyetheramine detergents, polyisobutyleneamine detergents, and Mannich base detergents; The thin-layer chromatography detection includes development and color development processes in sequence; The developing agent includes one or more of developing agent I, developing agent II and developing agent III; The developing agent I is methanol, and the developing agents II and III include one or more of the following: alcohols with 1 to 6 carbon atoms, aliphatic hydrocarbons with 5 to 12 carbon atoms, and cycloalkanes with 5 to 12 carbon atoms.

2. The method according to claim 1, wherein, The developing agent II includes one or more of isopropanol, n-hexane, and isobutanol; the developing agent III includes one or more of methanol, isopropanol, and n-propanol.

3. The method according to claim 1, wherein, The developing agent II is a mixture of isopropanol and n-hexane, or isobutanol; the developing agent III is a mixture of methanol and isopropanol, or n-propanol. The volume ratio of isopropanol to n-hexane is 1:(1~4); the volume ratio of methanol to isopropanol is 1:(2~4). The volume ratio of the developing solvent to the sample to be tested on the thin-layer chromatographic plate is (15~25):

1.

4. The method according to claim 1, wherein, The developing solvent is developing solvent I. If the main reagent characteristic points on the thin-layer chromatographic plate obtained after development show colored spots, then the sample to be tested contains a polyetheramine detergent; the main reagent characteristic points are R. f The range of values ​​is 0.5 to 0.

7.

5. The method according to claim 1, wherein, The developing solvent is developing solvent II. If the main reagent characteristic point on the thin-layer chromatographic plate obtained after development has a colored spot, then the sample to be tested contains a polyisobutylene amine detergent; the main reagent characteristic point is R. f The range of values ​​is 0.3 to 0.

4.

6. The method according to claim 1, wherein, The method also includes: The first thin-layer chromatographic plate was developed using developing solvent I, the second thin-layer chromatographic plate was developed using developing solvent II, and the third thin-layer chromatographic plate was developed using developing solvent III. If the origin of the first, second, and third thin-layer chromatographic plates obtained by development has colored spots, then the main detergent for the sample to be tested is a Mannich base detergent.

7. The method according to claim 1, wherein, The method further includes: before performing the thin-layer chromatography detection, using developing solvent A to perform thin-layer chromatography detection on the sample to be tested; the developing solvent A includes ester compounds, preferably fatty lipids, more preferably ethyl acetate; the developing height of the pre-chromatographic detection is greater than the developing height of the thin-layer chromatography detection.

8. The method according to claim 1, wherein, In the colorimetric treatment, the colorimetric agent includes a ninhydrin solution with a concentration of 0.1~10wt%; the solvent of the ninhydrin solution includes water and / or ethanol.

9. The method according to claim 1, wherein, In the thin-layer chromatography, the developing plate is one or more of silica gel, modified silica gel, alumina, and modified alumina.

10. The method according to claim 1, wherein, The method further includes: concentrating gasoline to obtain the sample to be tested; The concentration factor is 20 to 100.

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