CN114264740A - Method for measuring effective components in circulating catalyst for synthesizing methacrolein - Google Patents
Method for measuring effective components in circulating catalyst for synthesizing methacrolein Download PDFInfo
- Publication number
- CN114264740A CN114264740A CN202111516614.1A CN202111516614A CN114264740A CN 114264740 A CN114264740 A CN 114264740A CN 202111516614 A CN202111516614 A CN 202111516614A CN 114264740 A CN114264740 A CN 114264740A
- Authority
- CN
- China
- Prior art keywords
- catalyst
- circulating catalyst
- content
- diethylmethylamine
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 122
- 238000000034 method Methods 0.000 title claims abstract description 58
- STNJBCKSHOAVAJ-UHFFFAOYSA-N Methacrolein Chemical compound CC(=C)C=O STNJBCKSHOAVAJ-UHFFFAOYSA-N 0.000 title claims abstract description 50
- 230000002194 synthesizing effect Effects 0.000 title claims abstract description 25
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 64
- 239000006227 byproduct Substances 0.000 claims abstract description 54
- GNVRJGIVDSQCOP-UHFFFAOYSA-N n-ethyl-n-methylethanamine Chemical compound CCN(C)CC GNVRJGIVDSQCOP-UHFFFAOYSA-N 0.000 claims abstract description 53
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 32
- 239000000126 substance Substances 0.000 claims abstract description 24
- HPNMFZURTQLUMO-UHFFFAOYSA-N diethylamine Chemical compound CCNCC HPNMFZURTQLUMO-UHFFFAOYSA-N 0.000 claims abstract description 23
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000004817 gas chromatography Methods 0.000 claims abstract description 18
- 238000011084 recovery Methods 0.000 claims abstract description 15
- 238000004458 analytical method Methods 0.000 claims abstract description 13
- 239000002608 ionic liquid Substances 0.000 claims abstract description 8
- UEHUZQKLOWYOMO-UHFFFAOYSA-N diethylazanium;acetate Chemical group CC(O)=O.CCNCC UEHUZQKLOWYOMO-UHFFFAOYSA-N 0.000 claims abstract description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 24
- 238000004451 qualitative analysis Methods 0.000 claims description 15
- 238000004587 chromatography analysis Methods 0.000 claims description 13
- 239000007789 gas Substances 0.000 claims description 13
- 238000005303 weighing Methods 0.000 claims description 9
- 238000005259 measurement Methods 0.000 claims description 8
- 239000012088 reference solution Substances 0.000 claims description 8
- 239000012085 test solution Substances 0.000 claims description 8
- 239000004576 sand Substances 0.000 claims description 7
- 238000005481 NMR spectroscopy Methods 0.000 claims description 4
- 238000012937 correction Methods 0.000 claims description 4
- 239000013558 reference substance Substances 0.000 claims description 4
- 230000004044 response Effects 0.000 claims description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- 239000012159 carrier gas Substances 0.000 claims description 3
- 239000001307 helium Substances 0.000 claims description 3
- 229910052734 helium Inorganic materials 0.000 claims description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 238000004949 mass spectrometry Methods 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 239000004480 active ingredient Substances 0.000 claims 4
- 230000008569 process Effects 0.000 abstract description 24
- 230000015572 biosynthetic process Effects 0.000 abstract description 11
- 238000003786 synthesis reaction Methods 0.000 abstract description 11
- 125000004122 cyclic group Chemical group 0.000 abstract description 8
- 238000001514 detection method Methods 0.000 abstract description 6
- 239000000243 solution Substances 0.000 description 27
- 239000012295 chemical reaction liquid Substances 0.000 description 20
- 238000002835 absorbance Methods 0.000 description 18
- 238000006555 catalytic reaction Methods 0.000 description 17
- 239000012071 phase Substances 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 14
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 10
- 230000003197 catalytic effect Effects 0.000 description 9
- 238000004064 recycling Methods 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000012086 standard solution Substances 0.000 description 5
- NBBJYMSMWIIQGU-UHFFFAOYSA-N Propionic aldehyde Chemical compound CCC=O NBBJYMSMWIIQGU-UHFFFAOYSA-N 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000011088 calibration curve Methods 0.000 description 3
- 239000012153 distilled water Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000001819 mass spectrum Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- ZTQSAGDEMFDKMZ-UHFFFAOYSA-N butyric aldehyde Natural products CCCC=O ZTQSAGDEMFDKMZ-UHFFFAOYSA-N 0.000 description 2
- 238000007036 catalytic synthesis reaction Methods 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000007069 methylation reaction Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000011987 methylation Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- -1 nitrogen-containing compound Chemical class 0.000 description 1
- 238000001225 nuclear magnetic resonance method Methods 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
Images
Landscapes
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
Abstract
The invention provides a method for measuring effective components in a circulating catalyst for synthesizing methacrolein, belongs to the technical field of chemical substance detection methods, and can solve the technical problem that the actual effective component content in the catalyst cannot be accurately measured due to the unclear type of a byproduct in the synthesis process of the methacrolein, so that the cyclic utilization of the catalyst is difficult to realize. The technical scheme comprises the following steps: the circulating catalyst is a diethylamine-acetic acid ionic liquid catalyst, the effective components of the circulating catalyst are diethylamine and acetic acid, and the determination method comprises the following steps: and (3) measuring the content of the by-products: determining the content of the by-product diethylmethylamine by gas chromatography; and (3) determination of effective components in the circulating catalyst: and calculating the loss amount of the circulating catalyst in the recovery process by adopting a total nitrogen analysis method, and determining the loss amount of the diethylamine in the circulating catalyst in the recovery process by combining the content of the byproduct, namely the diethylmethylamine, so as to obtain the actual effective content of the diethylamine in the circulating catalyst.
Description
Technical Field
The invention belongs to the technical field of chemical substance detection methods, and particularly relates to a method for determining effective components in a circulating catalyst for synthesizing methacrolein.
Background
Methacrolein (abbreviated as MAL) is an organic compound mainly used for the production of copolymers and resins, and is a raw material for the production of methacrylic acid and a raw material for thermoplastic monomers.
At present, in the synthesis process of methacrolein, organic acid and aliphatic amine are generally adopted as catalysts (for example, acetic acid and diethylamine are used as catalysts to carry out catalytic reaction), but the problem that the diethylamine-acetic acid ionic liquid catalyst is difficult to realize recycling in the process of catalyzing the synthesis of methacrolein is that the diethylamine-acetic acid ionic liquid catalyst exists in a reaction liquid in the form of ionic liquid after the main catalytic components diethylamine and acetic acid react in the process of catalyzing the synthesis of methacrolein, and side reactions occur in the reaction process, but the material structure and reaction mechanism of by-products are not clear, so that the content of the effective catalytic component diethylamine cannot be accurately quantified in the catalyst recycling process, and the conversion rate of propionaldehyde and the selectivity of methacrolein in the process of catalyzing the synthesis of methacrolein by the catalyst recycling are difficult to control,
therefore, on the basis of qualitative and quantitative analysis of the by-products, further determining the content of the actual effective components in the catalyst is the key to realize the recycling of the catalyst.
Disclosure of Invention
Aiming at the technical problem that the actual content of effective components in the catalyst cannot be accurately measured due to the unclear type of the by-product in the synthesis process of the methacrolein at present, and further the recycling of the catalyst is difficult to realize, the invention provides the method for measuring the effective components in the circulating catalyst for synthesizing the methacrolein, which is simple and convenient to operate and high in accuracy, so that the recycling of the catalyst can be realized, and the aim of saving the production cost is fulfilled.
In order to achieve the purpose, the invention adopts the technical scheme that:
the method for measuring the effective components in the circulating catalyst for synthesizing the methacrolein, wherein the circulating catalyst is a diethylamine-acetic acid ionic liquid catalyst, and the effective components are diethylamine and acetic acid, and the measuring method comprises the following steps:
and (3) measuring the content of the by-products: determining the content of the by-product diethylmethylamine by gas chromatography;
and (3) determination of effective components in the circulating catalyst: and calculating the loss amount of the circulating catalyst in the recovery process by adopting a total nitrogen analysis method, determining the loss amount of the diethylamine in the circulating catalyst in the recovery process by combining the content of the diethylmethylamine, and further obtaining the actual effective content of the effective component diethylamine in the circulating catalyst.
Preferably, before the step of measuring the content of the by-products, a step of qualitatively analyzing the by-products is further included.
Preferably, the step of qualitatively analyzing the by-product is to perform qualitative analysis of the by-product diethylmethylamine in the circulating catalyst by using a method combining gas chromatography, nuclear magnetic resonance and mass spectrometry.
Preferably, in the by-product qualitative analysis and by-product content determination step, the gas chromatography comprises:
taking absolute ethyl alcohol as an internal standard substance, taking an N, N-diethylmethylamine standard sample as a reference substance, weighing a certain amount of absolute ethyl alcohol and the N, N-diethylmethylamine standard sample to prepare a reference solution, carrying out chromatographic analysis to obtain a chromatogram of the reference solution, and calculating a correction factor f, wherein the formula is as follows:
in the above formula (I), AsAnd ArThe peak areas or peak heights of the absolute ethyl alcohol and the N, N-diethylmethylamine standard sample respectively, msAnd mrRespectively adding absolute ethyl alcohol and N, N-diethylmethylamine standard sample;
taking absolute ethyl alcohol as an internal standard substance and the circulating catalyst as a sample to be detected, weighing a certain amount of absolute ethyl alcohol and the circulating catalyst to prepare a test solution, performing chromatographic analysis to obtain a chromatogram of the test solution, and calculating the content (m) according to the peak response value of the component chromatogram of the sample to be detected containing the internal standard substancei) The formula is as follows:
Aiand AsThe peak areas or peak heights of the sample to be detected and the internal standard substance are respectively, and ms is the amount of the internal standard substance added.
Preferably, in the by-product qualitative analysis and by-product content determination step, the chromatographic conditions of the gas chromatography are as follows:
a chromatographic column: KB-624;
column temperature: maintaining the initial temperature at 70 deg.C for 12 min; the temperature rise rate is 40 ℃/min at 70-240 ℃, and the temperature is kept for 20 min;
sample introduction amount: 0.1-0.3 μ l;
carrier gas: helium gas;
the split ratio is as follows: 20: 1;
a detector: a hydrogen flame ionization detector; detector temperature: 300 ℃; sample injector: a shunt sampling device; sample injector temperature: at 300 ℃.
Preferably, the amount of the sample is 0.1. mu.l.
Compared with the prior art, the invention has the advantages and positive effects that:
1. the method for determining the effective components in the circulating catalyst for synthesizing the methacrolein realizes the qualitative analysis of the byproduct diethylmethylamine in the process of catalytically synthesizing the methacrolein by combining the gas chromatography, the nuclear magnetic resonance and the mass spectrum, and indirectly determines the content of the effective catalytic activity diethylamine in the catalyst recycled in the synthesis process of the methacrolein by determining the content of the byproduct diethylmethylamine on the basis, thereby solving the technical problem that the content of the effective component diethylamine in the diethylamine-acetic acid ionic liquid can not be determined;
2. the method for measuring the effective components in the circulating catalyst for synthesizing the methacrolein effectively solves the problems that the catalyst is difficult to realize the recycling, so that the cost is high in the industrial production and the economic benefit is not ideal, and simultaneously, the problems that the conversion rate of propionaldehyde and the selectivity of the methacrolein are difficult to stably control when the effective components in the catalyst are not quantitatively analyzed are also avoided;
3. the method for measuring the effective components in the circulating catalyst for synthesizing the methacrolein has the characteristics of simple and convenient operation, high accuracy and the like.
Drawings
FIG. 1 is a gas chromatogram of methacrolein reaction liquid after first catalysis by the catalyst provided by the embodiment of the invention;
FIG. 2 is a gas chromatogram of methacrolein reaction liquid after the second catalysis by the catalyst provided by the embodiment of the invention;
FIG. 3 is a gas chromatogram of methacrolein reaction solution after the third catalysis by the catalyst provided by the embodiment of the invention;
FIG. 4 is a gas chromatogram of methacrolein reaction solution after the fourth catalysis by the catalyst provided by the embodiment of the present invention;
FIG. 5 is a gas chromatogram of the oil phase of methacrolein reaction liquid after the third catalysis by the catalyst provided by the embodiment of the invention;
FIG. 6 is a gas chromatogram of methacrolein reaction liquid after adding a standard diethyl methylamine to the oil phase of methacrolein reaction liquid after the third catalysis by the catalyst provided by the embodiment of the present invention;
FIG. 7 is a diagram of a standard quality spectrum of diethylmethylamine provided in an example of the present invention;
FIG. 8 is a mass spectrum of diethylmethylamine in a homogeneous reaction liquid provided by an example of the present invention;
FIG. 9 is a gas chromatogram in a homogeneous phase reaction liquid provided by an embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a method for measuring effective components in a circulating catalyst for synthesizing methacrolein, wherein the circulating catalyst is a diethylamine-acetic acid ionic liquid catalyst, and the effective components are diethylamine and acetic acid, and the method comprises the following steps:
s1, measuring the content of the by-products: determining the content of the by-product diethylmethylamine by gas chromatography;
s2, determination of effective components in the circulating catalyst: and calculating the loss amount of the circulating catalyst in the recovery process by adopting a total nitrogen analysis method, and determining the loss amount of the diethylamine in the circulating catalyst in the recovery process by combining the content of the diethylmethylamine so as to obtain the actual effective content of the diethylamine in the circulating catalyst.
In the embodiment, a method for determining effective components in a circulating catalyst for synthesizing methacrolein is provided, and qualitative analysis of a byproduct, namely diethylmethylamine in a process of catalytically synthesizing methacrolein is realized by combining a gas chromatography method, a nuclear magnetic resonance method and a mass spectrum method.
Further, the invention makes clear that in the process of synthesizing methacrolein (abbreviated as MAL) by cyclic catalysis, the effective catalytic component diethylamine in the catalyst can generate methylation reaction to generate diethylmethylamine, and the loss of the effective component diethylamine also exists in the catalyst cyclic recovery, specifically:
(1) the method comprises the steps of respectively measuring the total nitrogen content in a catalyst solution when the amine content of the catalyst is 6.8% by using a total nitrogen analysis method (performed according to the specification of HJ 636-2012, hereinafter referred to as a total nitrogen analysis method), and then catalytically synthesizing methacrolein MAL;
(2) collecting a water phase in an MAL reaction solution to concentrate and recover a catalyst, removing excessive water in the reaction solution by adopting a reduced pressure distillation method in the process, and analyzing and measuring the total nitrogen content of the recovered catalyst and the nitrogen content in the concentrated water phase by a total nitrogen analysis method after the mass of the concentrated catalyst is consistent with the mass of a fresh catalyst so as to determine whether the catalyst is damaged or not in the process of synthesizing the MAL by circulating catalysis;
based on the above experiments, the following conclusions were drawn:
the invention discovers that the total nitrogen content in the recovered catalyst solution is obviously reduced compared with the total nitrogen content in the newly prepared catalyst in the catalyst recovery process by a total nitrogen analysis method, wherein the total nitrogen content in the newly prepared catalyst (6.8 percent concentration) is about 9500mg/L, and the total nitrogen content in the catalyst solution recovered after the MAL is synthesized by the first catalysis is 7000-8000 mg/L; in an experiment, the loss of nitrogen in the recovered catalyst solution is related to the concentration and recovery conditions of the catalyst, the heating temperature of the catalyst is higher when the catalyst is concentrated and recovered at normal pressure, the loss of nitrogen of the catalyst is also the largest, the total nitrogen content in the recovered catalyst solution is 7000-7500 mg/L, and the nitrogen content in a distilled water phase in the concentration process is 2000-2500 mg/L;
however, with the increase of the vacuum degree and the reduction of the heating temperature of the catalyst during the concentration and the recovery of the catalyst, the nitrogen loss amount of the catalyst and the nitrogen loss amount of the catalyst recovered under normal pressure are reduced, the total nitrogen content in the recovered catalyst solution is 8000-8500 mg/L, and the nitrogen content in the distilled water phase during the concentration process is 1000-1500 mg/L.
The invention defines the proportion of a byproduct, namely diethylmethylamine, generated after the methylation of diethylamine in each cyclic catalysis process of the catalyst in the cyclic catalysis synthesis of the MAL in the whole catalyst solution, and can accurately calculate the contents of effective catalytic components, namely diethylamine and the byproduct, namely diethylmethylamine in the cyclic catalyst solution according to the total nitrogen content in the cyclic catalyst solution and the total nitrogen loss in the cyclic recovery process of the catalyst, so as to stably control the catalytic stability of the MAL synthesis process in industrial production.
In a preferred embodiment, before the step of measuring the content of the by-products, a step of qualitative analysis of the by-products is further included.
In a preferred embodiment, the step of qualitatively analyzing the by-product is to perform qualitative analysis of the by-product diethylmethylamine in the circulating catalyst by using a method combining gas chromatography, nuclear magnetic resonance and mass spectrometry.
In the above preferred embodiment, the qualitative analysis of by-products comprises the following steps:
(1) recycling a circulating catalyst for catalyzing the synthesis of the methacrolein each time, then carrying out catalytic synthesis reaction of the methacrolein, and taking a reaction instant liquid and adding methanol in the reaction process, wherein the volume ratio of the reaction instant liquid to the methanol is 1: 2, changing the reaction liquid into a uniform phase, performing chromatographic analysis, and comparing the components in the reaction system each time and the content change condition of each component;
(2) analyzing the homogeneous phase reaction liquid prepared in the step (1) by a gas chromatograph-mass spectrometer, and preliminarily analyzing and determining a byproduct, namely diethylmethylamine, generated in the catalytic process of the catalyst according to a determination result;
(3) because most of the catalyst and the catalyst by-product exist in the aqueous phase reaction liquid, selecting the oil phase reaction liquid of the methacrolein as a blank control group to carry out chromatographic analysis so as to determine the composition of the methacrolein, then adding a small amount of diethylmethylamine standard substance into the oil phase reaction liquid, uniformly mixing and carrying out chromatographic analysis for verifying the determination result in the step (2);
(4) and (3) comparing the chromatographic peak position of the diethylmethylamine in the step (2) with the analytical result of the diethylmethylamine standard substance in the step (3) under the same detection condition, and determining that the catalyst generates side reaction to become a final byproduct diethylmethylamine in the circulating catalytic synthesis process of the methacrolein, so that the catalytic activity is lost.
In a preferred embodiment, the gas chromatography comprises, in the by-product qualitative analysis and by-product content determination steps:
taking absolute ethyl alcohol as an internal standard substance, taking an N, N-diethylmethylamine standard sample as a reference substance, weighing a certain amount of absolute ethyl alcohol and the N, N-diethylmethylamine standard sample to prepare a reference solution, carrying out chromatographic analysis to obtain a chromatogram of the reference solution, and calculating a correction factor f, wherein the formula is as follows:
in the above formula (I), AsAnd ArThe peak areas or peak heights of the absolute ethyl alcohol and the N, N-diethylmethylamine standard sample respectively, msAnd mrRespectively adding absolute ethyl alcohol and N, N-diethylmethylamine standard sample;
taking absolute ethyl alcohol as an internal standard substance and the circulating catalyst as a sample to be detected, weighing a certain amount of absolute ethyl alcohol and the circulating catalyst to prepare a test solution, performing chromatographic analysis to obtain a chromatogram of the test solution, and calculating the content (m) according to the peak response value of the component chromatogram of the sample to be detected containing the internal standard substancei) The formula is as follows:
Aiand AsThe peak areas or peak heights, m, of the sample to be measured and the internal standard substance respectivelysFor the amount of internal standard added.
In a preferred embodiment, in the step of by-product qualitative analysis and by-product content determination, the chromatographic conditions of the gas chromatography are as follows:
a chromatographic column: KB-624;
column temperature: maintaining the initial temperature at 70 deg.C for 12 min; the temperature rise rate is 40 ℃/min at 70-240 ℃, and the temperature is kept for 20 min;
sample introduction amount: 0.1-0.3 μ l;
carrier gas: helium gas;
the split ratio is as follows: 20: 1;
a detector: a hydrogen flame ionization detector; detector temperature: 300 ℃; sample injector: a shunt sampling device; sample injector temperature: at 300 ℃.
In a preferred embodiment, the sample size is 0.1. mu.l.
In order to more clearly describe the method for determining the effective components in the circulating catalyst for synthesizing methacrolein provided by the embodiments of the present invention in detail, the following description will be given with reference to specific examples.
Example 1
The embodiment provides a qualitative analysis method of a byproduct diethylmethylamine, which comprises the following specific steps:
(1) in the process of synthesizing methacrolein by catalyst circulation catalysis, respectively taking 10mL of reaction liquid of the catalyst catalyzing the first catalysis time to the fourth catalysis time, adding 20mL of methanol for full mixing, taking 1mL of sample for gas chromatography analysis (obtained by repeating six experiments after the experiment results are obtained) after the reaction liquid and the methanol form a uniform solution, and finally obtaining a chromatogram analysis chart (shown in figures 1-4). when the catalyst is used for synthesizing methacrolein by catalyst circulation catalysis, the relative content of components with peaks appears in a trend of obvious increase along with the increase of the catalyst circulation catalysis times when the reaction liquid level is 9.25 min;
(2) analyzing the homogeneous phase reaction solution prepared in the step (1) by a gas chromatograph-mass spectrometer to obtain a mass spectrogram and a gas chromatogram of the diethylmethylamine (as shown in figures 8-9), and preliminarily analyzing and determining a byproduct generated in the catalytic process of the catalyst to be the diethylmethylamine according to a determination result;
(3) according to the results, the methacrolein oil phase reaction liquid after the third reaction is selected and firstly subjected to gas chromatography detection (the measurement result is shown in fig. 5), and the detection result shows that the methacrolein oil phase reaction liquid almost has no byproduct, namely, diethylmethylamine, so that the methacrolein oil phase reaction liquid is selected as a blank control group to be subjected to chromatographic analysis, and then a small amount of diethylmethylamine standard substance is added into the oil phase reaction liquid to be uniformly mixed and subjected to chromatographic analysis (the measurement result is shown in fig. 6) for verifying the measurement result in the step (2);
(4) comparing the chromatographic peak position of the diethylmethylamine in the step (2) with the analytical result of the diethylmethylamine standard substance in the step (3) under the same detection condition, the chromatographic peak time of the diethylmethylamine standard substance is about 9.25min, and is basically consistent with the chromatographic peak time and the chromatographic shape of a byproduct diethylmethylamine generated in the catalyst circulation process, so that the generated byproduct is diethylmethylamine in the synthesis process of methacrolein can be verified and confirmed.
Example 2
The embodiment provides a method for measuring effective components in a circulating catalyst for synthesizing methacrolein, which specifically comprises the following steps:
(1) and (3) measuring the content of the by-products: the content of the byproduct diethylmethylamine is measured by gas chromatography, and the method specifically comprises the following steps:
taking absolute ethyl alcohol as an internal standard substance, taking an N, N-diethylmethylamine standard sample as a reference substance, weighing a certain amount of absolute ethyl alcohol and the N, N-diethylmethylamine standard sample to prepare a reference solution, carrying out chromatographic analysis to obtain a chromatogram of the reference solution, and calculating a correction factor f, wherein the formula is as follows:
in the formula (I), As and Ar are peak areas or peak heights of anhydrous ethanol and the N, N-diethylmethylamine standard sample respectively, and ms and mr are the amounts of the anhydrous ethanol and the N, N-diethylmethylamine standard sample added respectively;
taking absolute ethyl alcohol as an internal standard substance and a circulating catalyst as a sample to be detected, weighing a certain amount of absolute ethyl alcohol and the circulating catalyst to prepare a test solution, performing chromatographic analysis to obtain a chromatogram of the test solution, and calculating the content (m) according to the peak response value of the component chromatogram of the sample to be detected containing the internal standard substancei) The formula is as follows:
Aiand AsThe peak areas or peak heights, m, of the sample to be measured and the internal standard substance respectivelysIs the amount of added internal standard;
(2) and (3) determination of effective components in the circulating catalyst: calculating the loss amount of the circulating catalyst in the recovery process by adopting a total nitrogen analysis method (performed according to the specification of HJ 636-2012), determining the loss amount of the diethylamine in the circulating catalyst in the recovery process by combining the content of the diethylmethylamine, and further obtaining the actual effective content of the diethylamine and the acetic acid in the circulating catalyst, wherein the total nitrogen analysis process is specifically as follows:
a) the principle of the method is as follows:
converting nitrogen of a nitrogen-containing compound in a sample into nitrate by using an alkaline potassium persulfate solution at 120-124 ℃, respectively measuring absorbances A220 and A275 at wavelengths of 220nm and 275nm by using an ultraviolet spectrophotometry, calculating a corrected absorbance A according to a formula (1), wherein the total nitrogen (in terms of N) content is in direct proportion to the corrected absorbance A.
A＝A220－2A275 (1)
b) And (3) an analysis step:
drawing standard curve
Respectively weighing 0.00mL, 0.20mL, 0.50mL, 1.00mL, 3.00mL and 7.00mL of potassium nitrate standard use solution in a 25mL glass colorimetric tube with a plug and a ground mouth, adding water to dilute the solution to 10.00mL, adding 5.00mL of alkaline potassium persulfate solution, placing the colorimetric tube in a high-pressure steam sterilizer, heating the colorimetric tube until a top pressure valve blows air, and closing the valve and then closing the valveHeating to 120 ℃ and timing, and keeping the temperature between 120 ℃ and 124 ℃ for 30 min. And then taking out the colorimetric tubes, adding 1.0ml of hydrochloric acid solution into each colorimetric tube after the solution is cooled, diluting the solution to 25ml of marked line by using water, and measuring absorbance of the standard solution at the positions with the wavelengths of 220nm and 275nm in a 10mm quartz cuvette respectively. Corrected absorbance at zero concentration AbCorrected absorbance A of other Standard seriessAnd the difference A thereofrCalculated according to the formulae (2), (3) and (4) with the total nitrogen (in N) content (. mu.g) as abscissa and corresponding to ArValues are plotted as ordinate against calibration curve.
Ab＝Ab220-2Ab275 (2)
As＝As220-2As275 (3)
Ar＝As-Ab (4)
In the above formula:
Ab: corrected absorbance of zero concentration (blank) solution; a. theb220: absorbance of zero concentration (blank) solution at wavelength 220 nm; a. theb275: absorbance of zero concentration (blank) solution at wavelength 275 nm; a. thes: corrected absorbance of the standard solution; a. thes220: absorbance of the standard solution at a wavelength of 220 nm; a. thes275: absorbance of the standard solution at a wavelength of 275 nm; a. ther: the difference between the absorbance corrected for the standard solution and the absorbance corrected for the zero concentration (blank) solution.
Measurement of samples
10.00ml of the sample was measured in a 25ml glass cuvette with a plug and ground and measured according to the same procedure as in the drawing of the standard curve.
③ measurement of blank
10.00ml of distilled water was measured in a 25ml glass colorimetric tube with a plug and the measurement was carried out according to the same procedure as in the drawing of the standard curve.
c) And (4) calculating a result:
the difference Ar between the corrected absorbance of the sample and the corrected absorbance of the blank test is calculated with reference to the formulas (2) to (4), and the mass concentration rho (mg/L) of the total nitrogen in the sample is calculated according to the formula (5).
In the formula:
ρ: mass concentration of total nitrogen (in N) in the sample, mg/L; ar: the difference value between the corrected absorbance of the sample and the corrected absorbance of the blank test; a: the intercept of the calibration curve; b: the slope of the calibration curve; v: sample volume, mL; f: dilution factor.
Claims (6)
1. The method for measuring the effective components in the circulating catalyst for synthesizing the methacrolein is characterized in that the circulating catalyst is a diethylamine-acetic acid ionic liquid catalyst, and the effective components are diethylamine and acetic acid, and the measuring method comprises the following steps:
and (3) measuring the content of the by-products: determining the content of the by-product diethylmethylamine by gas chromatography;
and (3) determination of effective components in the circulating catalyst: and calculating the loss amount of the circulating catalyst in the recovery process by adopting a total nitrogen analysis method, and determining the loss amount of the diethylamine in the circulating catalyst in the recovery process by combining the content of the byproduct, namely the diethylmethylamine, so as to obtain the actual effective content of the effective component, namely the diethylamine, in the circulating catalyst.
2. The method for measuring active ingredients in a circulating catalyst for synthesizing methacrolein according to claim 1, further comprising a step of qualitative analysis of by-products before said step of measuring the content of by-products.
3. The method for determining an active ingredient in a circulating catalyst for synthesizing methacrolein as set forth in claim 2, wherein said step of qualitatively analyzing by-products is a step of qualitatively analyzing by-products diethylmethylamine in said circulating catalyst by a combination of gas chromatography, nuclear magnetic resonance and mass spectrometry.
4. The method for measuring active ingredients in a circulating catalyst for synthesizing methacrolein as set forth in claim 3, wherein said gas chromatography comprises, in the step of by-product qualitative analysis and by-product content measurement:
taking absolute ethyl alcohol as an internal standard substance, taking an N, N-diethylmethylamine standard sample as a reference substance, weighing a certain amount of absolute ethyl alcohol and the N, N-diethylmethylamine standard sample to prepare a reference solution, carrying out chromatographic analysis to obtain a chromatogram of the reference solution, and calculating a correction factor f, wherein the formula is as follows:
in the above formula (I), AsAnd ArThe peak areas or peak heights of the absolute ethyl alcohol and the N, N-diethylmethylamine standard sample respectively, msAnd mrRespectively adding absolute ethyl alcohol and N, N-diethylmethylamine standard sample;
taking absolute ethyl alcohol as an internal standard substance and the circulating catalyst as a sample to be detected, weighing a certain amount of absolute ethyl alcohol and the circulating catalyst to prepare a test solution, performing chromatographic analysis to obtain a chromatogram of the test solution, and calculating the content (m) according to the peak response value of the component chromatogram of the sample to be detected containing the internal standard substancei) The formula is as follows:
Aiand AsThe peak areas or peak heights, m, of the sample to be measured and the internal standard substance respectivelysFor the amount of internal standard added.
5. The method for measuring active ingredients in a circulating catalyst for synthesizing methacrolein as set forth in claim 3, wherein in the step of by-product qualitative analysis and by-product content measurement, the chromatographic conditions of said gas chromatography are:
a chromatographic column: KB-624;
column temperature: maintaining the initial temperature at 70 deg.C for 12 min; the temperature rise rate is 40 ℃/min at 70-240 ℃, and the temperature is kept for 20 min;
sample introduction amount: 0.1-0.3 μ l;
carrier gas: helium gas;
the split ratio is as follows: 20: 1;
a detector: a hydrogen flame ionization detector; detector temperature: 300 ℃; sample injector: a shunt sampling device; sample injector temperature: at 300 ℃.
6. The method according to claim 5, wherein the amount of the sample is 0.1. mu.l.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111516614.1A CN114264740B (en) | 2021-12-13 | Method for measuring effective components in circulating catalyst for synthesizing methacrolein |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111516614.1A CN114264740B (en) | 2021-12-13 | Method for measuring effective components in circulating catalyst for synthesizing methacrolein |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114264740A true CN114264740A (en) | 2022-04-01 |
| CN114264740B CN114264740B (en) | 2024-05-31 |
Family
ID=
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5360878A (en) * | 1992-03-04 | 1994-11-01 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Highly crosslinked silicon polymers for gas chromatography columns |
| CN104311403A (en) * | 2014-10-08 | 2015-01-28 | 中国科学院过程工程研究所 | Production method for methylacrolein |
| CN107941926A (en) * | 2016-10-13 | 2018-04-20 | 中国石油化工股份有限公司 | A kind of assay method of triethylamine content |
| CN108473452A (en) * | 2015-12-02 | 2018-08-31 | 赢创德固赛有限公司 | Method for epoxidation propylene |
| CN109507309A (en) * | 2018-10-22 | 2019-03-22 | 重庆中邦科技有限公司 | The gas chromatography analysis method of triethylamine and isopropanol in recycling design |
| CN111632629A (en) * | 2020-06-23 | 2020-09-08 | 中国科学院过程工程研究所 | Method for recovering ionic liquid catalyst in preparation process of coal-based methacrolein |
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5360878A (en) * | 1992-03-04 | 1994-11-01 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Highly crosslinked silicon polymers for gas chromatography columns |
| CN104311403A (en) * | 2014-10-08 | 2015-01-28 | 中国科学院过程工程研究所 | Production method for methylacrolein |
| CN108473452A (en) * | 2015-12-02 | 2018-08-31 | 赢创德固赛有限公司 | Method for epoxidation propylene |
| CN107941926A (en) * | 2016-10-13 | 2018-04-20 | 中国石油化工股份有限公司 | A kind of assay method of triethylamine content |
| CN109507309A (en) * | 2018-10-22 | 2019-03-22 | 重庆中邦科技有限公司 | The gas chromatography analysis method of triethylamine and isopropanol in recycling design |
| CN111632629A (en) * | 2020-06-23 | 2020-09-08 | 中国科学院过程工程研究所 | Method for recovering ionic liquid catalyst in preparation process of coal-based methacrolein |
Non-Patent Citations (1)
| Title |
|---|
| LIU FAN等: "Kinetic Studies on Both Synthesis of Methacrolein Catalyzed by an Ionic Liquid and Catalyst Deactivation", INDUSTRIAL ＆ ENGINEERING CHEMISTRY RESEARCH, vol. 60, no. 15, 7 April 2021 (2021-04-07), pages 5412 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104634895B (en) | A kind of method that Ultra Performance Liquid Chromatography triple quadrupole bar tandem mass spectrometer detects 6 kinds of sweeting agents in Chinese liquor simultaneously | |
| CN109696499A (en) | A kind of nitrosamine Sensitive Determination method in the water based on high resolution mass spec | |
| CN108982379A (en) | The methods and applications of NO3-N and NO2-N nitrogen total amount in a kind of measurement sample | |
| CN113030294B (en) | Method for detecting organic solvent in white spirit | |
| CN114487155A (en) | Indirect determination method for impurity content in torasemide injection | |
| CN114264740A (en) | Method for measuring effective components in circulating catalyst for synthesizing methacrolein | |
| CN114264740B (en) | Method for measuring effective components in circulating catalyst for synthesizing methacrolein | |
| CN110687239B (en) | Method for measuring chromatographic response relative mass correction factor of impurity derivative in sample | |
| CN108445102B (en) | Quantitative analysis method of 3-methylthio propanol in high-salt liquid-state brewed soy sauce | |
| CN114324657B (en) | Method for detecting myrcene in soil by combining purging and trapping with GC-MS (gas chromatography-mass spectrometer) | |
| CN113109460B (en) | Method for analyzing high-boiling-point solvent residue in OLED material | |
| CN113655012B (en) | High COD wastewater total nitrogen testing method | |
| CN113933406A (en) | Method for detecting content of formaldehyde in white spirit sample | |
| CN114166979A (en) | Method for measuring content of 1-tetralone | |
| CN111024872B (en) | Method for rapidly detecting 3-methylthio propanol in sesame-flavor liquor | |
| CN110646531A (en) | Ion chromatography quantitative analysis method for raw material diethanolamine in reaction liquid for synthesizing iminodiacetic acid by dehydrogenation of diethanolamine | |
| CN105738640A (en) | Preservation method and automatic analysis method of trace divalent sulfide ions in water sample | |
| CN102230925A (en) | Method for determining content of sorbic acid in additive for cigarettes | |
| CN110632204B (en) | Method for detecting hordenine hydrochloride | |
| CN114184737B (en) | Method for measuring content of hexafluoro-cyclo-triphosphonitrile | |
| CN115406987B (en) | Method for establishing GC-MS detection analysis conditions of halosulfuron-methyl | |
| CN113325096B (en) | Detection method of 1- (2,3-dimethylphenyl) ethanol related substances | |
| CN117649897B (en) | Method for predicting gas production of soy sauce in shelf life | |
| CN105954219A (en) | Method for determining content of diacetyl in wine | |
| CN109406698B (en) | Method for measuring content of single-chain substituted dimethyl benzyl ammonium chloride by HPLC |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |