A method for analyzing olefin compounds in petroleum or chemical products

Abstract

The application provides application of a PB reaction in analysis of olefin compounds in a mixture. The application applies the Paternò-Büchi reaction to the olefin compounds in the mixture, and proposes a new method for analyzing the olefins by combining the PB reaction with mass spectrometry. The C=C bond in the olefin is converted into an oxygen-containing four-membered ring with stronger polarity by the PB reaction, so that the olefin can be ionized and the ionization response is sensitive, and the number of carbon-carbon double bonds in the olefin can be determined according to the oxygenation number of the product; the ionization effect before and after the PB reaction and the ionization product difference can quickly and accurately realize the selective characterization of the olefins in a complex matrix. The analysis method uses the selectivity and ionization specificity of the PB reaction, can distinguish straight-chain olefins, non-straight-chain olefins and naphthenes from the molecular recognition, can quickly and effectively realize the selective characterization of the olefins, has high selectivity, significantly enhances the sensitivity of the ionization response of the olefins, and expands the detectable range of the olefins.

Description

Technical Field

[0001] This invention belongs to the field of olefin compound analysis technology, specifically relating to an analytical method for olefin compounds in mixtures and the application of the PB reaction, and further relating to an analytical method for olefin compounds in petroleum or chemical products and the application of the PB reaction. Background Technology

[0002] Olefins are important raw materials in modern organic chemical industry, used to produce lubricating oil base oils, surfactants, additives, and pour point depressants. As a key component of secondary petroleum processing products (such as catalytic cracking and delayed coking), the molecular and structural composition of olefins affects product quality. Furthermore, during catalytic cracking and thermal processing, olefins participate in and control free radical chain reactions, and their double bonds can complex with metal ions, influencing the catalytic processing. Therefore, olefins are crucial raw materials in modern organic chemical industry and key components of petroleum products. A comprehensive understanding of their molecular composition provides valuable information for targeted process optimization and reaction mechanism research. Studying the molecular composition and structure of olefin compounds in petroleum products is of great significance for targeted process optimization and product quality assessment.

[0003] However, olefins in petroleum have a wide carbon number distribution and complex composition, including chain olefins and cyclic olefins; moreover, the matrix is ​​complex, and the analysis of olefins is easily affected by other hydrocarbons (cycloalkanes, straight-chain alkanes). Therefore, selective enrichment is usually performed before olefin analysis. Traditional methods are mainly based on gas chromatography-mass spectrometry (GC-MS) to analyze the molecular composition of olefins, but they can only analyze low-carbon-number olefins. GC has been reported to separate 1-3 components of n-alkanes, isoalkanes, olefins, cycloalkanes, and aromatics (PIONA) in low-fraction (boiling point <221℃) fuel oil. However, olefins and cycloalkanes have the same elemental formula, and GC cannot separate these isomers when the carbon number is greater than C12. To improve separation selectivity, Ag-based methods are used... + Impregnation or modified chromatographic methods have been developed and used; however, traditional olefin analysis mostly employs GC-MS, which, limited by the GC injection vaporization temperature, can only analyze low-carbon-number olefins, typically detecting olefins with no more than 14 carbon atoms. Furthermore, olefins are mainly found in complex systems such as petroleum products, and are subject to interference from complex hydrocarbon matrices, making it challenging to distinguish olefins from other hydrocarbons and achieve comprehensive characterization of their molecular composition.

[0004] Current characterization of olefin molecular composition is mainly limited to low-carbon-number olefins. To deepen our understanding of product oil composition and achieve targeted optimization of processing, a comprehensive understanding of the molecular composition of all olefin components is essential. As the carbon number of hydrocarbons increases, the complexity of compound types increases dramatically, and the number and types of interfering components in olefin analysis also increase significantly. Therefore, the analysis of all olefin components, especially heavy components, is challenging.

[0005] Therefore, finding a more suitable analytical method to overcome the limitations of the existing traditional analytical methods and to develop a comprehensive and highly selective analytical method for the molecular composition of olefins has become one of the focal points of attention for many forward-thinking researchers in the field. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide an analytical method for olefin compounds in mixtures and the application of the PB reaction, particularly an analytical method for olefin compounds in petroleum or chemical products. The present invention applies the Pastenò-Büchi (PB) reaction to the analysis of olefin compounds in petroleum or chemical products, and combines it with mass spectrometry to achieve highly sensitive ionization and detection of olefins. Subsequently, a rapid method for distinguishing olefins from other hydrocarbons is developed, achieving selective characterization of olefins in complex systems. The analytical method provided by the present invention is rapid, efficient, and highly selective, significantly enhancing the sensitivity of the olefin ionization response and expanding the detectable range of olefins.

[0007] This invention provides the application of the PB reaction in the analysis of olefin compounds in mixtures;

[0008] The PB reaction is the Pasternò-Büchi reaction.

[0009] Preferably, the mixture comprises a mixture containing olefins or a mixture composed of pure olefins;

[0010] The olefin compounds include low-carbon-number olefin compounds and high-carbon-number olefin compounds;

[0011] The number of carbon atoms in the low-carbon olefin compound is 2 to 13;

[0012] The high-carbon-number olefin compound has >14 carbon atoms.

[0013] Preferably, the analysis includes one or more of the following: whether the mixture contains olefin compounds, the total number of olefin compounds, the type of olefin compounds, the number of carbon-carbon double bonds in olefin compounds, the carbon atom distribution of olefin compounds, the unsaturation distribution of olefin compounds, the number of carbon atoms in a single olefin compound, the molecular formula of a single olefin compound, and the unsaturation of a single olefin compound.

[0014] The reaction reagents for the PB reaction include organic reagents containing carbonyl groups and / or organic reagents containing aldehyde groups;

[0015] The analysis specifically involves the combined application of PB reaction and mass spectrometry.

[0016] The mass spectrometry includes one or more of low-resolution mass spectrometry, high-resolution mass spectrometry, and ultra-high-resolution mass spectrometry.

[0017] Preferably, the ionization mode of the mass spectrometer includes one or more of atmospheric pressure chemical ionization, atmospheric pressure photoionization, electrospray ionization, electron bombardment ionization, and negative ion chemical ionization;

[0018] The ionization solvent of the mass spectrometer includes one or more of the following: n-hexane, n-pentane, cyclohexane, n-heptane, isooctane, toluene, methanol, ethanol, and acetonitrile.

[0019] The reaction reagents for the PB reaction include one or more of the following: acetone, dimethyl acetone, 2-acetylpyridine, benzaldehyde, formaldehyde, acetaldehyde, 2-pyridinecarboxaldehyde, 3-formaldehydepyridine, 4-pyridinecarboxaldehyde, 3-acetylpyridine, and 3-acetylpyrrole.

[0020] The power of the ultraviolet lamp used in the PB reaction is 5-250W;

[0021] The wavelength of the ultraviolet lamp used for the PB reaction is 150–400 nm.

[0022] The reaction time of the PB reaction is 1 second to 150 minutes.

[0023] Preferably, the carbon-carbon double bond in the olefin compound is reacted via a PB reaction to obtain a polar oxobutane compound containing heteroatoms;

[0024] The mixture includes petroleum products, chemical products, or olefin polymers;

[0025] The petroleum products include crude oil and all secondary processing products of crude oil, such as one or more of catalytic cracking slurry oil, gasoline, diesel, and Fischer-Tropsch synthetic oil.

[0026] This invention provides a method for analyzing olefin compounds in a mixture, comprising the following steps:

[0027] 1) After separating the mixture, a saturated hydrocarbon component containing olefin compounds is obtained. The sample containing the saturated hydrocarbon component containing olefin compounds is mixed with an ionized solvent and then subjected to mass spectrometry analysis to obtain the first analytical spectrum.

[0028] 2) After mixing the saturated hydrocarbon component containing olefins obtained in the above steps with the reaction solvent, the reaction is carried out under ultraviolet light irradiation to obtain the reaction product. The reaction product is then mixed with the ionization solvent again to obtain the mass spectrometry analysis sample.

[0029] 3) Perform mass spectrometry analysis again on the mass spectrometry sample obtained in the above steps to obtain the second analytical spectrum;

[0030] The analytical results of the olefin compounds in the mixture were obtained by comparing and analyzing the first and second analytical spectra.

[0031] The mixture includes mixtures containing olefins or mixtures composed of pure olefins;

[0032] When the mixture is a mixture containing olefins, steps 1) to 3) above are performed; when the mixture is a mixture composed of pure olefins, steps 2) to 3) above are performed.

[0033] Preferably, the mixture comprises petroleum products;

[0034] The petroleum products include one or more of catalytic cracking slurry oil, gasoline, diesel, and Fischer-Tropsch synthetic oil.

[0035] After separation, the mixture is further divided into one or more of aromatic components, resinous components, and asphaltenes.

[0036] The mass spectrometry includes ultra-high resolution mass spectrometry.

[0037] Preferably, the saturated hydrocarbon component containing olefin compounds includes alkane compounds, cycloalkane compounds, and olefin compounds;

[0038] The first analytical spectrum includes the carbon number DBE spectrum of CH class compounds and / or the carbon number DBE spectrum of O1 class compounds;

[0039] In the mass spectrometry analysis in step 1), the compounds that can be detected are those with DBE≥1, and the compounds that cannot be detected are alkane compounds with DBE=0.

[0040] The compounds with DBE≥1 include cycloalkane compounds and / or non-linear olefin compounds.

[0041] Preferably, after the PB reaction, in the saturated hydrocarbon component containing olefin compounds, the olefin compounds are derivatized into polar oxygen-containing four-membered ring compounds that can be detected by mass spectrometry.

[0042] The second analytical spectrum includes the carbon number DBE diagram of CH-type compounds after the PB reaction and / or the carbon number DBE diagram of O1-type compounds after the PB reaction;

[0043] In the mass spectrometry analysis in step 3), the straight-chain linear olefin compounds in the saturated hydrocarbon fraction containing olefin compounds before the PB reaction can be detected by mass spectrometry after the PB reaction.

[0044] In the mass spectrometry analysis in step 3), the compounds with DBE≥1 include the products of linear olefin compounds after the PB reaction, the products of non-linear olefin compounds after the PB reaction, and cycloalkanes that do not undergo the PB reaction.

[0045] Preferably, the comparative analysis specifically includes the following steps:

[0046] By comparing the carbon number DBE diagrams of CH compounds, O1 compounds, and O1 compounds after the PB reaction, the analytical results of linear olefin compounds and / or non-linear olefin compounds were obtained.

[0047] The analytical results of cycloalkanes were obtained by comparing the carbon number DBE diagrams of CH compounds and the carbon number DBE diagrams of CH compounds after the PB reaction.

[0048] The analytical results include one or more of the following: whether olefin compounds are present, the total number of olefin compounds, the type of olefin compounds, the number of carbon-carbon double bonds in olefin compounds, the carbon atom distribution of olefin compounds, the unsaturation distribution of olefin compounds, the number of carbon atoms in a single olefin compound, the molecular formula of a single olefin compound, and the degree of unsaturation of a single olefin compound.

[0049] This invention creatively applies the Pastenò-Büchi reaction to the analysis of olefin compounds in mixtures, and proposes a novel method for analyzing olefins using the Pastenò-Büchi (PB) reaction combined with mass spectrometry. Through the PB reaction, this invention converts the C=C bonds in olefins into oxygen-containing four-membered rings with higher polarity, making the olefins ionizable and exhibiting a sensitive ionization response, thus solving the current problem of the inability to directly detect olefins by ionization. Furthermore, since all carbon-carbon double bonds in the olefin are oxidized to oxygen-containing four-membered rings, the number of carbon-carbon double bonds in the olefin can be determined by detecting the number of oxygen atoms in the product.

[0050] This invention also specifically designs an analytical method for the comprehensive characterization of olefin molecular composition in complex petroleum systems. It employs a PB reaction combined with ultra-high resolution mass spectrometry (UHRMS) to achieve comprehensive characterization of olefin molecular composition in complex systems, expanding the detection range of olefins and obtaining information on the molecular composition of all components. Furthermore, since olefins are mainly found in complex matrices such as petroleum products, it is essential to selectively distinguish and characterize olefins from other hydrocarbons with similar properties (such as cycloalkanes and aromatics). Therefore, this invention develops a logical pathway to distinguish olefins from other hydrocarbons, utilizing the selectivity and ionization specificity of the PB reaction to differentiate straight-chain olefins, non-straight-chain olefins, and cycloalkanes through molecular recognition. Traditional olefin analysis methods require complex and time-consuming chromatographic separation steps to distinguish between olefins and cycloalkanes. Therefore, the olefin analysis method based on the PB reaction combined with UHRMS can rapidly and effectively achieve selective characterization of olefins in complex matrices.

[0051] Experimental results show that the analytical method provided by this invention is faster, more efficient, and more selective than existing analytical methods, significantly enhancing the sensitivity of olefin ionization response and expanding the detectable range of olefins. Attached Figure Description

[0052] Figure 1 The mechanism diagram of the Pasternò-Büchi reaction provided by this invention;

[0053] Figure 2 A simplified flowchart illustrating the APCI and PB-APCI UHRMS analysis processes for distinguishing linear alkenes, nonlinear alkenes, cycloalkanes, and aromatic hydrocarbons provided by this invention.

[0054] Figure 3 The image shows the APCI Orbitrap MS carbon number DBE diagrams of the catalytic cracking slurry before and after the PB reaction in Example 1 of this invention. Detailed Implementation

[0055] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0056] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0057] The purity of the raw materials used in this invention is not particularly limited. Preferably, the purity is that of analytical grade or conventional purity in the field of olefin mixture analysis.

[0058] All raw materials of this invention are conventional in the field, and each brand name and abbreviation is clear and distinct in its relevant application. Those skilled in the art can purchase them from the market or prepare them by conventional methods based on the brand name, abbreviation and corresponding application.

[0059] All processes in this invention are referred to by abbreviations that are common abbreviations in the field. Each abbreviation is clear and specific in its relevant application area, and those skilled in the art can understand its conventional process steps based on the abbreviation.

[0060] This invention provides the application of the PB reaction in the analysis of olefin compounds in mixtures;

[0061] The PB reaction is the Pasternò-Büchi reaction.

[0062] Specifically, the Pasternò-Büchi (PB) reaction is a method for the efficient derivatization of carbon-carbon double bonds. The PB reaction is a UV-initiated [2+2] cycloaddition reaction in which C=C reacts with an excited carbonyl group (which can originate from a ketone or aldehyde) to form an oxetane. Oxetanes are small in size, have high ring strain, are structurally stable, and possess a certain degree of polarity.

[0063] See Figure 1 , Figure 1 This is a schematic diagram of the mechanism of the Pasternò-Büchi reaction provided by the present invention.

[0064] In this invention, the mixture comprises preferably a mixture containing olefins or a mixture composed of pure olefins.

[0065] In this invention, the olefin compounds preferably include low-carbon-number olefin compounds and high-carbon-number olefin compounds.

[0066] In this invention, the number of carbon atoms in the low-carbon olefin compound is preferably 2 to 13, more preferably 4 to 11, and even more preferably 6 to 9.

[0067] In this invention, the number of carbon atoms in the high-carbon-number olefin compound is preferably >14, more preferably 15 to 45, more preferably 24 to 45, and even more preferably 34 to 35.

[0068] In this invention, the analysis preferably includes one or more of the following: whether the mixture contains olefin compounds, the total number of olefin compounds, the type of olefin compounds, the number of carbon-carbon double bonds in olefin compounds, the carbon atom distribution of olefin compounds, the unsaturation distribution of olefin compounds, the number of carbon atoms in a single olefin compound, the molecular formula of a single olefin compound, and the unsaturation of a single olefin compound. More preferably, it includes whether the mixture contains olefin compounds, the total number of olefin compounds, the type of olefin compounds, the number of carbon-carbon double bonds in olefin compounds, the carbon atom distribution of olefin compounds, the unsaturation distribution of olefin compounds, the number of carbon atoms in a single olefin compound, the molecular formula of a single olefin compound, and the unsaturation of a single olefin compound.

[0069] In this invention, the reaction reagents for the PB reaction preferably include organic reagents containing carbonyl groups and / or organic reagents containing aldehyde groups, more preferably organic reagents containing carbonyl groups or organic reagents containing aldehyde groups.

[0070] In this invention, the analysis is preferably performed by combining the PB reaction with mass spectrometry.

[0071] In this invention, the mass spectrometry preferably includes one or more of low-resolution mass spectrometry, high-resolution mass spectrometry, and ultra-high-resolution mass spectrometry, and more preferably low-resolution mass spectrometry, high-resolution mass spectrometry, or ultra-high-resolution mass spectrometry.

[0072] In this invention, the ionization mode of the mass spectrometer preferably includes one or more of atmospheric pressure chemical ionization, atmospheric pressure photoionization, electrospray ionization and negative ion chemical ionization, and more preferably atmospheric pressure chemical ionization, atmospheric pressure photoionization, electrospray ionization, electron bombardment ionization or negative ion chemical ionization.

[0073] In this invention, the ionization solvent of the mass spectrometer preferably includes one or more of the following: n-hexane, n-pentane, cyclohexane, n-heptane, isooctane, toluene, methanol, ethanol, and acetonitrile.

[0074] In this invention, the reaction reagent for the PB reaction preferably includes a reagent containing a carbonyl group, preferably one or more of acetone, dimethyl acetone, 2-acetylpyridine, benzaldehyde, formaldehyde, acetaldehyde, 2-pyridinecarboxaldehyde, 3-formaldehyde pyridine, 4-pyridinecarboxaldehyde, 3-acetylpyridine, and 3-acetylpyrrole, more preferably acetone, dimethyl acetone, 2-acetylpyridine, benzaldehyde, formaldehyde, acetaldehyde, 2-pyridinecarboxaldehyde, 3-formaldehyde pyridine, 4-pyridinecarboxaldehyde, 3-acetylpyridine, or 3-acetylpyrrole.

[0075] In this invention, the power of the ultraviolet lamp for the PB reaction is preferably 5 to 250W, more preferably 100 to 200W.

[0076] In this invention, the wavelength of the ultraviolet lamp used for the PB reaction is preferably 150-400 nm, more preferably 200-400 nm.

[0077] In this invention, the reaction time of the PB reaction is preferably 1s to 150min, more preferably 5 to 60min.

[0078] In this invention, the carbon-carbon double bond in the olefin compound is preferably obtained by the PB reaction to yield a polar oxobutane compound containing heteroatoms.

[0079] In this invention, the mixture preferably includes petroleum products, chemical products, or olefin polymers.

[0080] In this invention, the petroleum products preferably include crude oil and all secondary processing products of crude oil, such as one or more of catalytic cracking slurry oil, gasoline, diesel oil and Fischer-Tropsch synthetic oil, more preferably catalytic cracking slurry oil, gasoline, diesel oil or Fischer-Tropsch synthetic oil.

[0081] This invention applies the PB reaction to the analysis of olefin compounds in mixtures, and further combines it with mass spectrometry to achieve comprehensive characterization of the molecular composition of olefins in complex systems. Firstly, this invention achieves soft ionization of olefins by derivatizing the carbon-carbon double bonds of olefins into more polar oxobutanes containing heteroatoms through the PB reaction, thereby improving the mass spectrometric response of olefins. Secondly, since olefins are mainly found in complex matrices such as petroleum products, it is essential to selectively distinguish and characterize olefins from other hydrocarbons with similar properties (such as cycloalkanes and aromatics). Therefore, this invention, based on achieving highly sensitive ionization of olefins, further provides a method for rapidly distinguishing different hydrocarbons in complex matrices.

[0082] This invention provides a method for analyzing olefin compounds in a mixture, comprising the following steps:

[0083] 1) After separating the mixture, a saturated hydrocarbon component containing olefin compounds is obtained. The sample containing the saturated hydrocarbon component containing olefin compounds is mixed with an ionized solvent and then subjected to mass spectrometry analysis to obtain the first analytical spectrum.

[0084] 2) After mixing the saturated hydrocarbon component containing olefins obtained in the above steps with the reaction solvent, the reaction is carried out under ultraviolet light irradiation to obtain the reaction product. The reaction product is then mixed with the ionization solvent again to obtain the mass spectrometry analysis sample.

[0085] 3) Perform mass spectrometry analysis again on the mass spectrometry sample obtained in the above steps to obtain the second analytical spectrum;

[0086] The analytical results of the olefin compounds in the mixture were obtained by comparing and analyzing the first and second analytical spectra.

[0087] In this invention, the mixture includes a mixture containing olefins or a mixture composed of pure olefins.

[0088] In this invention, when the mixture is a mixture containing olefins, steps 1) to 3) above are performed; when the mixture is a mixture composed of pure olefins, steps 2) to 3) above are performed.

[0089] The present invention first separates the mixture to obtain a saturated hydrocarbon component containing olefin compounds. The sample of the saturated hydrocarbon component containing olefin compounds is then mixed with an ionized solvent and subjected to mass spectrometry analysis to obtain a first analytical spectrum.

[0090] In this invention, the mixture preferably includes petroleum products and chemical products.

[0091] In this invention, the petroleum products preferably include crude oil and all secondary processing products of crude oil, such as one or more of catalytic cracking slurry oil, gasoline, diesel oil and Fischer-Tropsch synthetic oil, more preferably catalytic cracking slurry oil, gasoline, diesel oil or Fischer-Tropsch synthetic oil.

[0092] In this invention, after the mixture is separated, the obtained components preferably include one or more of aromatic components, resinous components and asphaltenes, more preferably aromatic components, resinous components or asphaltenes.

[0093] In this invention, the mass spectrometry preferably includes ultra-high resolution mass spectrometry.

[0094] In this invention, the saturated hydrocarbon component containing olefin compounds preferably includes alkane compounds, cycloalkane compounds, and olefin compounds.

[0095] In this invention, the first analytical spectrum preferably includes the carbon number DBE spectrum of CH-type compounds and / or the carbon number DBE spectrum of O1-type compounds, more preferably the carbon number DBE spectrum of CH-type compounds or the carbon number DBE spectrum of O1-type compounds.

[0096] In this invention, in the mass spectrometry analysis of step 1), the compounds that can be detected are preferably compounds with DBE≥1, and the compounds that cannot be detected are alkane compounds with DBE=0.

[0097] In this invention, the compounds with DBE≥1 preferably include cycloalkane compounds and / or non-linear olefin compounds.

[0098] In this invention, the saturated hydrocarbon component containing olefins obtained in the above steps is mixed with a reaction solvent and subjected to a PB reaction under ultraviolet light to obtain a reaction product. The reaction product is then mixed with an ionized solvent again to obtain a mass spectrometry analysis sample.

[0099] In this invention, after the PB reaction, the saturated hydrocarbon component containing olefin compounds is preferably derivatized into polar oxygen-containing four-membered ring compounds that can be detected by mass spectrometry.

[0100] In this invention, the second analytical spectrum preferably includes the carbon number DBE spectrum of CH-type compounds after the PB reaction and / or the carbon number DBE spectrum of O1-type compounds after the PB reaction, more preferably the carbon number DBE spectrum of CH-type compounds after the PB reaction or the carbon number DBE spectrum of O1-type compounds after the PB reaction.

[0101] Finally, the present invention performs a second mass spectrometry analysis on the mass spectrometry sample obtained in the above steps to obtain a second analytical spectrum;

[0102] By comparing and analyzing the first and second analytical spectra, the analytical results of the olefin compounds in the mixture were obtained.

[0103] In this invention, during the mass spectrometry analysis in step 3), the straight-chain linear olefin compounds in the saturated hydrocarbon fraction containing olefin compounds before the PB reaction are preferably detectable by mass spectrometry after the PB reaction.

[0104] In this invention, the mass spectrometry analysis in step 3) preferably includes the product of the reaction of linear olefin compound PB, the product of the reaction of non-linear olefin compound PB, and cycloalkane compound that does not undergo the PB reaction.

[0105] In this invention, the comparative analysis preferably includes the following steps:

[0106] By comparing the carbon number DBE diagrams of CH compounds, O1 compounds, and O1 compounds after the PB reaction, the analytical results of linear olefin compounds and / or non-linear olefin compounds were obtained.

[0107] The analytical results of cycloalkanes were obtained by comparing the carbon number DBE diagrams of CH compounds and the carbon number DBE diagrams of CH compounds after the PB reaction.

[0108] In this invention, the analytical results preferably include one or more of the following: whether or not an olefin compound is present, the total number of olefin compounds, the type of olefin compound, the number of carbon-carbon double bonds in an olefin compound, the carbon atom distribution of an olefin compound, the unsaturation distribution of an olefin compound, the number of carbon atoms in a single olefin compound, the molecular formula of a single olefin compound, and the degree of unsaturation of a single olefin compound. More preferably, the results include whether or not an olefin compound is present, the total number of olefin compounds, the type of olefin compound, the number of carbon-carbon double bonds in an olefin compound, the carbon atom distribution of an olefin compound, the unsaturation distribution of an olefin compound, the number of carbon atoms in a single olefin compound, the molecular formula of a single olefin compound, and the degree of unsaturation of a single olefin compound.

[0109] To complete and refine the overall analytical process, better ensure the accuracy, stability, and repeatability of olefin compound analysis, and improve analytical efficiency, the analytical method for olefin compounds in petroleum or chemical products may specifically include the following steps:

[0110] The analytical method provided by this invention for the comprehensive characterization of olefin molecular composition in complex petroleum systems, specifically for the detection of olefins in petroleum using the PB reaction combined with APCUI HRMS, mainly consists of three steps: 1. Enriching olefins to a saturated fraction; 2. Performing the PB reaction on the olefins in the saturated fraction to derivatize them (the principle of the PB reaction is described in...). Figure 1 3. Perform APCI UHRMS analysis on the reaction products.

[0111] Specific steps: First, using the Chinese Petroleum and Natural Gas Industry Standard Analytical Method (SY / T 519-2008), petroleum is separated into saturated hydrocarbons, aromatics, resins, and asphaltenes, with olefins retained in the saturated fraction. The saturated fraction is dissolved in a vial containing acetone. The vial opening is kept open, and a UV lamp is placed directly above the vial, irradiating the reaction perpendicularly to the opening. After the reaction, residual acetone is removed by purging with nitrogen. The reaction product is dissolved in a solvent, followed by mass spectrometry analysis.

[0112] Based on improving the olefin response, a strategy is proposed to distinguish different hydrocarbons in petroleum by utilizing the differences in PB reaction selectivity and ionization characteristics of different hydrocarbon compounds.

[0113] See Figure 2 , Figure 2 A simplified flowchart illustrating the process of APCI and PB-APCIUHRMS analysis for distinguishing linear olefins, nonlinear olefins, cycloalkanes, and aromatic hydrocarbons provided by this invention.

[0114] A flowchart distinguishing the components in petroleum and the sources of unsaturation is shown below. Figure 2 As shown. First, hydrocarbons other than aromatics are retained in the saturated fraction through four-component separation. Then, direct APCI-UHRMS analysis is performed on the saturated fraction. Compounds that can be detected by ionization (DBE≥1) are cycloalkanes or non-straight-chain alkenes; straight-chain alkenes cannot be ionized. Finally, APCI-UHRMS analysis is performed on the saturated fraction after the PB reaction. Compounds producing an oxygenation peak (i.e., acetone addition product) belong to alkenes, while those without an oxygenation product (compound type CH) belong to cycloalkanes, because the PB reaction targets the C=C bond, not the CH bond of cycloalkanes. Therefore, straight-chain alkenes are not detectable by APCI before the PB reaction but have an oxygenation product detected after the PB reaction; non-straight-chain alkenes are detectable by direct APCI before the PB reaction and have an oxygenation product as the main component after the PB reaction; and cycloalkanes are detectable by APCI before the PB reaction but have no oxygenation product after the PB reaction.

[0115] It should be noted that, specifically, the analyzed sample can be any sample containing olefins or pure olefins other than petroleum products, such as olefin polymers or olefin molecules. If the sample is any other sample containing olefins or pure olefins, then there is no need for four-component separation; the sample can be directly dissolved and subjected to the PB reaction for ionization detection.

[0116] It should be noted that, specifically, the PB reaction reagent can be any compound containing a carbonyl or aldehyde group, such as acetone, dimethyl acetone, 2-acetylpyridine, benzaldehyde, formaldehyde, acetaldehyde, 2-pyridinecarboxaldehyde, 3-formaldehyde pyridine, 4-pyridinecarboxaldehyde, 3-acetylpyridine, and 3-acetylpyrrole, etc.

[0117] It should be noted that, specifically, the mass spectrometer used can be low-resolution mass spectrometry, high-resolution mass spectrometry, or ultra-high-resolution mass spectrometry, etc.

[0118] It should be noted that, specifically, the ionization methods can include atmospheric pressure chemical ionization, atmospheric pressure photoionization, electrospray ionization, electron impact ionization, and negative ion chemical ionization, among other mass spectrometry ionization methods. Commonly used ionization solvents include n-hexane, n-pentane, cyclohexane, n-heptane, isooctane, toluene, methanol, ethanol, and acetonitrile.

[0119] To further illustrate the present invention, the following detailed description of the analytical method for olefin compounds in mixtures and the application of the PB reaction provided by the present invention is given in conjunction with the embodiments. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are given only to further illustrate the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0120] Example 1

[0121] Experimental conditions:

[0122] (1) Sample pretreatment

[0123] Sample: Catalytic cracking slurry. The catalytic cracking slurry was separated into saturated hydrocarbons, aromatics, resins, and asphaltenes using the Chinese Petroleum and Natural Gas Industry Standard Analytical Method (SY / T 519-2008), with olefins retained in the saturated fraction. A small amount of the saturated fraction was dissolved in isooctane to prepare a 0.2 mg / mL solution, which was then analyzed by direct APCI-Orbitrap MS. Another saturated fraction was subjected to the PB reaction.

[0124] (2) PB reaction

[0125] The saturated fraction was dissolved in a vial containing acetone. The vial was kept open, and a UV lamp was placed directly above the vial, irradiating the reaction perpendicularly to the mouth of the vial. After the reaction, residual acetone was removed by purging with nitrogen. The reaction product was dissolved in isooctane and then analyzed by APCI-Orbitrap mass spectrometry.

[0126] (3) Orbitrap MS analysis

[0127] Mass spectrometer model: Thermo Fisher Scientific Orbitrap Fusion MS, resolution 500,000 (FWHM). Ionization source: Atmospheric pressure chemical ionization source.

[0128] See Figure 3 , Figure 3 The images show the DBE (Density Optimization) graphs of the carbon number of the catalytic cracking slurry before and after the PB reaction in Example 1 of this invention, as shown in APCI Orbitrap MS. Specifically, (a) is the DBE graph of the carbon number of CH compounds before the PB reaction, (b) is the DBE graph of the carbon number of O1 compounds before the PB reaction, (c) is the DBE graph of the carbon number of CH compounds after the PB reaction, and (d) is the DBE graph of the carbon number of O1 compounds after the PB reaction.

[0129] Experimental results: Combining Figure 3Analysis was performed on the FCC slurry oil, which underwent four-component separation to remove aromatic hydrocarbons, while alkanes and alkenes remained in the saturated fraction. The saturated fraction was then directly analyzed using APCI UHRMS. Figure 3 In (a), the CH-type compounds with a DBE ≥ 1 may be cycloalkanes or non-straight-chain alkenes, but it is impossible to determine their specific class at this point. After the saturated fraction undergoes the PB reaction, the alkenes combine with acetone and are detected as O1-type compounds in APCI MS analysis. Figure 3 As shown in (d), the O1 class compounds with 25-40 carbons and DBE 1-4 distribution within the black dashed box are undetectable before the reaction but detectable after the reaction, indicating that this part is a straight-chain olefin; the O1 class compounds with 25-40 carbons and DBE 4-10 can be detected before and after the reaction, belonging to non-straight-chain olefins such as cycloalkenes or cyclophenylene olefins. Figure 3 (c) represents the CH compounds that can be detected after the reaction. These substances do not participate in the PB reaction, and before the reaction ( Figure 3 (a) can also be detected as cycloalkanes.

[0130] The above provides a detailed description of the analytical method for olefin compounds in petroleum or chemical products and its application in the PB reaction provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of this invention, including the best mode, and to enable any person skilled in the art to practice this invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the wording of the claims, or if they include equivalent structural elements that are not substantially different from the wording of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for analyzing olefin compounds in a mixture, characterized in that, Includes the following steps: 1) After separating the mixture, a saturated hydrocarbon component containing olefin compounds is obtained. The sample containing the saturated hydrocarbon component containing olefin compounds is mixed with an ionized solvent and then subjected to mass spectrometry analysis to obtain the first analytical spectrum. The saturated hydrocarbon component containing olefin compounds includes alkanes, cycloalkanes, and olefins. The first analytical spectrum includes the carbon number DBE spectrum of CH class compounds and the carbon number DBE spectrum of O1 class compounds; 2) After mixing the saturated hydrocarbon component containing olefins obtained in the above steps with the reaction solvent, the reaction is carried out under ultraviolet light irradiation to obtain the reaction product. The reaction product is then mixed with the ionization solvent again to obtain the mass spectrometry analysis sample. 3) After performing a second mass spectrometry analysis on the mass spectrometry sample obtained in the above steps, a second analytical spectrum is obtained; The second analytical spectrum includes the carbon number DBE diagram of CH-type compounds after the PB reaction and the carbon number DBE diagram of O1-type compounds after the PB reaction; After comparing and analyzing the first and second analytical spectra, the analytical results of olefin compounds in the mixture were obtained, including: by comparing the carbon number DBE diagrams of CH compounds, O1 compounds and O1 compounds after the PB reaction, the analytical results of linear olefin compounds and non-linear olefin compounds were obtained. The analytical results of cycloalkanes were obtained by comparing the carbon number DBE diagrams of CH compounds and the carbon number DBE diagrams of CH compounds after the PB reaction. In the mass spectrometry analysis in step 1), the detectable compounds are CH compounds with a carbon number DBE ≥ 1, and the undetectable compounds are CH compounds with a carbon number DBE = 0 (alkanes). The CH class compounds with a carbon number DBE ≥ 1 include cycloalkanes and / or non-straight-chain olefins. In the mass spectrometry analysis in step 3), the straight-chain linear olefin compounds in the saturated hydrocarbon fraction containing olefin compounds before the PB reaction can be detected by mass spectrometry after the PB reaction. In the mass spectrometry analysis in step 3), the compounds with carbon number DBE≥1 of the O1 class compounds include the products of the reaction of linear olefin compounds PB, the products of the reaction of non-linear olefin compounds PB, and cycloalkane compounds that do not undergo the PB reaction. The mixture includes a mixture containing olefins, and the mixture is a petroleum product; The PB reaction is the Pasternò-Büchi reaction.

2. The analytical method according to claim 1, characterized in that, The petroleum products include one or more of catalytic cracking slurry oil, gasoline, diesel, and Fischer-Tropsch synthetic oil. After separation, the mixture is further divided into one or more of aromatic components, resinous components, and asphaltenes. The mass spectrometry includes ultra-high resolution mass spectrometry.

3. The analytical method according to claim 2, characterized in that, The analytical results include one or more of the following: whether olefin compounds are present, the total number of olefin compounds, the type of olefin compounds, the number of carbon-carbon double bonds in olefin compounds, the carbon atom distribution of olefin compounds, the unsaturation distribution of olefin compounds, the number of carbon atoms in a single olefin compound, the molecular formula of a single olefin compound, and the degree of unsaturation of a single olefin compound.

4. The analytical method according to claim 1, characterized in that, The olefin compounds include low-carbon-number olefin compounds and high-carbon-number olefin compounds.

5. The analytical method according to claim 4, characterized in that, The number of carbon atoms in the low-carbon olefin compound is 2 to 13; The high-carbon-number olefin compound has >14 carbon atoms.

6. The analytical method according to claim 1, wherein the reaction reagents for the PB reaction include organic reagents containing carbonyl groups and / or organic reagents containing aldehyde groups.

7. The analytical method according to claim 1, characterized in that, The ionization methods of the mass spectrometer include one or more of atmospheric pressure chemical ionization, atmospheric pressure photoionization, electrospray ionization, electron bombardment ionization, and negative ion chemical ionization.

8. The analytical method according to claim 1, characterized in that, The ionization solvent of the mass spectrometer includes one or more of the following: n-hexane, n-pentane, cyclohexane, n-heptane, isooctane, toluene, methanol, ethanol, and acetonitrile.

9. The analytical method according to claim 1, characterized in that, The reaction reagents for the PB reaction include one or more of the following: acetone, dimethyl acetone, 2-acetylpyridine, benzaldehyde, formaldehyde, acetaldehyde, 2-pyridinecarboxaldehyde, 3-formaldehydepyridine, 4-pyridinecarboxaldehyde, 3-acetylpyridine, and 3-acetylpyrrole.

10. The analytical method according to claim 1, characterized in that, The UV lamp power for the PB reaction is 5~250W; The wavelength of the ultraviolet lamp used for the PB reaction is 150~400nm; The reaction time of the PB reaction is 1 second to 150 minutes.

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