Furfural reaction liquid component determination method

Abstract

The invention discloses a furfural reaction liquid component determination method, belongs to the technical field of organic synthesis, provides a more suitable quality control method for a novel synthesis process for preparing furfural through catalytic reaction, can rapidly and accurately determine the content of furfural in a reaction liquid, better tracks the reaction process, researches the reaction mechanism, and improves the reaction quality. A reference basis is provided for central control analysis; the analysis method is high in accuracy and good in repeatability; through the selection of a DB-WAX gas chromatographic column, the optimization of chromatographic conditions and a pretreatment method of a reaction solution, a compound to be detected and adjacent components are subjected to baseline separation, and the separation degree of furfural and 5-methylfurfural is better; after the to-be-detected component is pretreated, the interference of miscellaneous peaks is reduced, the interaction force between the to-be-detected component and the chromatographic column is increased, the peak shape is symmetrical, and the forward inclination or trailing of the chromatographic peak is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of organic synthesis, and in particular relates to a method for determining the components of a furfural reaction solution. Background Art

[0002] Furfural, also known as furfural (α-furfural), is a colorless liquid and an important traditional fine chemical product. It is widely used in medicine, pesticides, resins, daily chemicals, casting, textiles, petroleum and other industries. Furfural can be used to produce derivatives through oxidation, condensation and other reactions. There are more than 1,000 chemical products directly or indirectly derived from furfural as raw materials. It has a wide range of applications and broad market prospects.

[0003] At present, furfural production mostly adopts the "one-step method" catalyzed by sulfuric acid. The raw corn cobs are crushed and mixed with the catalyst dilute sulfuric acid, hydrolyzed at high temperature and pressure to evaporate the crude aldehyde, and then distilled to obtain refined aldehyde. The process technology has problems such as low yield, high energy consumption, heavy pollution, and many side reactions. In addition, the furfural refining process suffers from severe polymerization and coking, resulting in high product losses.

[0004] Patent CN104280473B discloses a method for analyzing 5-hydroxymethylfurfural, characterized in that the analysis method adopts high performance liquid chromatography, and the chromatographic conditions are: ultraviolet detector, detection wavelength is 284nm; chromatographic column: C18 column; Patent CN104597180A discloses an analysis method for determining the furfural content in aromatic hydrocarbon extraction oil and raffinate oil, which includes using a polar filling column and optimizing chromatographic analysis conditions to completely separate the furfural components, and the furfural content can be obtained by an external standard method; Patent CN110879222A discloses a method for constructing a quantitative analysis curve of furfural in transformer oil and a method for detecting the furfural content, wherein furfural is dissolved in transformer oil to prepare furfural stock solutions with different concentration gradients; water is added to part of the furfural stock solution, ultrasonicated, centrifuged, and a raffinate is obtained, and the raffinate and the remaining furfural stock solution are respectively subjected to Raman spectroscopy determination.

[0005] The existing furfural component detection method is no longer applicable to the new furfural synthesis process. The above method does not have a detection method for the new catalytic synthesis reaction liquid. Therefore, it is necessary to develop a method for determining the main components of the new catalytic reaction synthesis furfural reaction liquid. Summary of the invention

[0006] The purpose of the implementation of this application is to provide a method for determining the components of furfural reaction liquid, based on the current status of furfural production technology and guided by the problems existing in the existing analysis process, to solve the technical problem that the existing furfural component detection method cannot be applied to the new furfural synthesis process.

[0007] To achieve the above purpose, the technical solution adopted in the present application is: to provide a method for determining the components of furfural reaction solution, which specifically comprises the following steps:

[0008] (I) Prepare standard solution: Weigh the furfural standard sample and the methyl furfural standard sample respectively, add solvent and make up to volume to prepare standard solution;

[0009] (II) Determination of correction factor: using a DB-WAX chromatographic column, setting the column temperature, vaporization temperature, detector temperature, nitrogen flow rate, hydrogen flow rate and air flow rate, aspirating the standard solution and injecting it into the chromatograph for analysis, recording the peak areas A1 and A2 of the two compounds in the standard solution; calculating the correction factor F value of methyl furfural according to formula 1:

[0010] F=(A2*M1) / (A1*M2) Formula 1

[0011] Where A1 is the peak area of ​​methyl furfural (cm 2 ), A2 is the peak area of ​​furfural (cm 2 ), M1 is the mass of methylfurfural (g), M2 is the mass of furfural (g);

[0012] (III) Content determination: Weigh the furfural reaction liquid, pre-treat the furfural reaction liquid to obtain a pre-treated liquid, inject the pre-treated liquid into a chromatograph for analysis, and calculate the furfural percentage content X according to Formula 2;

[0013] X=(F i *A i ) / [∑(F i *A i )]*100% Formula 2

[0014] Where, X is the percentage content (%) of component i in the sample, F i is the correction factor of component i (except methyl furfural, other components are calculated as 1), A i is the peak area of ​​component i (cm 2 ).

[0015] In one embodiment,

[0016] The mass ratio of the furfural standard sample to the methylfurfural standard sample in step (a) is 5:0.05-0.15, and preferably, the mass ratio of the furfural standard sample to the methylfurfural standard sample is 5:0.1.

[0017] In one embodiment,

[0018] In step (1), the purity of the furfural standard sample is greater than 99.9%, and the purity of the methylfurfural standard sample is greater than 99.0%.

[0019] In one embodiment,

[0020] The solvent for fixing the volume in step (i) is dichloromethane or chloroform. Preferably, the solvent for fixing the volume is dichloromethane.

[0021] In one embodiment,

[0022] In step (ii), the column temperature is 148-152°C, the vaporization temperature is 210-230°C, the detector temperature is 215-225°C, the nitrogen flow rate is 20mL / min, the hydrogen flow rate is 25mL / min, and the air flow rate is 135mL / min. Preferably, the column temperature is 150°C, the vaporization temperature is 220°C, and the detector temperature is 220°C.

[0023] In one embodiment,

[0024] The volume of the standard solution injected into the chromatograph in step (ii) is 0.5 μL.

[0025] In one embodiment,

[0026] The main components of the furfural reaction liquid in step (iii) include: trace corn cobs, furfural, methyl furfural, catalyst, sodium carbonate, methylglyoxal, formaldehyde, glyceraldehyde and ethanolaldehyde.

[0027] In one embodiment,

[0028] The specific steps of the pretreatment in step (iii) are: weigh 5-7 g of the furfural reaction solution, accurately transfer it to a test tube for dilution, ultrasonicate it, filter it with a microsample filter, and let it stand for 20 minutes.

[0029] In one embodiment,

[0030] The dilution solvent in step (iii) is dichloromethane or chloroform, and the ratio of the furfural reaction solution to the dilution solvent is 1g:1ml.

[0031] In one embodiment,

[0032] The volume of the pretreatment solution injected into the chromatograph in step (iii) is 0.5 μL.

[0033] The present application provides a method for determining the components of a furfural reaction liquid, and provides a more suitable quality control method for a novel catalytic reaction to prepare a furfural synthesis process. The method can quickly and accurately determine the furfural content in the reaction liquid, better track the reaction process, study the reaction mechanism, and provide a reference basis for in-process control analysis; and the analysis method has high accuracy and good repeatability; the selection of a DB-WAX gas chromatography column, the optimization of chromatographic conditions, and the pretreatment method of the reaction liquid enable baseline separation to be achieved between the test compound and adjacent components, and the separation of furfural and 5-methylfurfural is better; after the test component is pretreated, the interference of miscellaneous peaks is reduced, the interaction force between the test component and the chromatographic column is increased, the peak shape is symmetrical, and the chromatographic peak forward tilt or tailing is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 This is the gas chromatographic analysis diagram of Example 1. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clear, the present application is further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] The main components of the furfural reaction liquid include: trace corn cobs, furfural, 5-methylfurfural, catalyst, sodium carbonate, methylglyoxal, formaldehyde, glyceraldehyde and ethanolaldehyde.

[0038] DB-WAX chromatographic column is an ultra-high inert gas chromatography column (applicable to Intuvo 9000 gas chromatography system).

[0039] The purity of the furfural standard sample is greater than 99.9%, and the purity of the methylfurfural standard sample is greater than 99.0%.

[0040] Formula 1 and Formula 2 both require three parallel experiments, and the average value of the three parallel experiments is taken as the measurement result.

[0041] Gas phase analysis was quantitatively calculated using the area normalization method.

[0042] F=(A2*M1) / (A1*M2) Formula 1

[0043] Where A1 is the peak area of ​​methyl furfural (cm 2), A2 is the peak area of ​​furfural (cm 2 ), M1 is the mass of methylfurfural (g), M2 is the mass of furfural (g);

[0044] X=(F i *A i ) / [∑(F i *A i )]*100% Formula 2

[0045] Where, X is the percentage content (%) of component i in the sample, F i is the correction factor of component i (except methyl furfural, other components are calculated as 1), A i is the peak area of ​​component i (cm 2 ).

[0046] Example 1

[0047] (I) Prepare standard solution: weigh 4.9998 g of furfural standard sample and 0.1003 g of methyl furfural standard sample using a microbalance, transfer them into a round-bottom flask, add dichloromethane and shake thoroughly to make a standard solution;

[0048] (II) Determination of correction factor: Setting gas chromatography conditions: using DB-WAX chromatographic column, setting column temperature 150°C, vaporization temperature 220°C, detector temperature 220°C, nitrogen flow rate 20mL / min, hydrogen flow rate 25mL / min, air flow rate 135mL / min, separation R greater than 1.5, detected by hydrogen flame ionization detector, quantitative calculation by area normalization method; under stable chromatographic separation conditions, draw 0.5μL of standard solution and inject it into the chromatograph for analysis, record the peak areas A1 and A2 of the two compounds in the standard solution, calculate the correction factor F value of methylfurfural according to formula 1, the results are shown in Table 1;

[0049] (III) Content determination: Weigh 5.847 g of the furfural reaction solution, accurately transfer it to a test tube, add 6 mL of dichloromethane to dilute, ultrasonicate, filter with a microsample filter, and let stand for 20 min to obtain a pretreatment solution, maintaining the same separation conditions as when determining the correction factor; use a clean and dry microinjector to absorb 0.5 μL of the pretreatment solution and quickly inject it into the chromatograph for analysis, and the furfural percentage X is calculated according to Formula 2. The results are shown in Table 1.

[0050] Example 2

[0051] (I) Prepare standard solution: weigh 5.0030 g of furfural standard sample and 0.1090 g of methyl furfural standard sample using a microbalance, transfer them into a round-bottom flask, add dichloromethane and shake thoroughly to make a standard solution;

[0052] (II) Determination of correction factor: Set gas chromatography conditions: Use DB-WAX chromatographic column, set column temperature 150°C, vaporization temperature 210°C, detector temperature 215°C, nitrogen flow rate 20mL / min, hydrogen flow rate 25mL / min, air flow rate 135mL / min; Under stable chromatographic separation conditions, draw 0.5μL of standard solution and inject it into the chromatograph for analysis, record the peak areas A1 and A2 of the two compounds in the standard solution, and calculate the correction factor F value of methylfurfural according to formula 1. The results are shown in Table 1;

[0053] (III) Content determination: Weigh 6.541 g of the furfural reaction solution, accurately transfer it to a test tube, add 6.5 mL of chloroform to dilute, ultrasonicate, filter with a microsample filter, let stand for 20 min to obtain a pretreatment solution, and maintain the same separation conditions as when determining the correction factor; use a clean and dry microinjector to absorb 0.5 μL of the pretreatment solution and quickly inject it into the chromatograph for analysis, and the furfural percentage X is calculated according to Formula 2. The results are shown in Table 1.

[0054] Example 3

[0055] (I) Prepare standard solution: Use a microbalance to weigh 5.0110 g of furfural standard sample and 0.1008 g of methyl furfural standard sample, transfer them into a round-bottom flask, add dichloromethane and shake thoroughly to make a standard solution;

[0056] (II) Determination of correction factor: Set gas chromatography conditions: Use DB-WAX chromatographic column, set column temperature 150°C, vaporization temperature 230°C, detector temperature 225°C, nitrogen flow rate 20mL / min, hydrogen flow rate 25mL / min, air flow rate 135mL / min; Under stable chromatographic separation conditions, draw 0.5μL of standard solution and inject it into the chromatograph for analysis, record the peak areas A1 and A2 of the two compounds in the standard solution, and calculate the correction factor F value of methylfurfural according to formula 1. The results are shown in Table 1;

[0057] (III) Content determination: Weigh 6.921 g of the furfural reaction solution, accurately transfer it to a test tube, add 7 mL of chloroform to dilute, ultrasonicate, filter with a microsample filter, and let stand for 20 min to obtain a pretreatment solution, maintaining the same separation conditions as when determining the correction factor; use a clean and dry microinjector to absorb 0.5 μL of the pretreatment solution and quickly inject it into the chromatograph for analysis, and the furfural percentage X is calculated according to Formula 2. The results are shown in Table 1.

[0058] Example 4

[0059] (I) Prepare standard solution: Use a microbalance to weigh 4.9999 g of furfural standard sample and 0.0993 g of methyl furfural standard sample, transfer them into a round-bottom flask, add chloroform and shake thoroughly to make a standard solution;

[0060] (II) Determination of correction factor: Set gas chromatography conditions: Use DB-WAX chromatographic column, set column temperature 150°C, vaporization temperature 230°C, detector temperature 225°C, nitrogen flow rate 20mL / min, hydrogen flow rate 25mL / min, air flow rate 135mL / min; Under stable chromatographic separation conditions, draw 0.5μL of standard solution and inject it into the chromatograph for analysis, record the peak areas A1 and A2 of the two compounds in the standard solution, and calculate the correction factor F value of methylfurfural according to formula 1. The results are shown in Table 1;

[0061] (III) Content determination: Weigh 6.921 g of the furfural reaction solution, accurately transfer it to a test tube, add 7 mL of chloroform to dilute, ultrasonicate, filter with a microsample filter, and let stand for 20 min to obtain a pretreatment solution, maintaining the same separation conditions as when determining the correction factor; use a clean and dry microinjector to absorb 0.5 μL of the pretreatment solution and quickly inject it into the chromatograph for analysis, and the furfural percentage X is calculated according to Formula 2. The results are shown in Table 1.

[0062] Example 5

[0063] The difference between this embodiment and embodiment 1 is that in step (i), the mass ratio of the furfural standard sample to the methylfurfural standard sample is 5:0.05, and the remaining operations are the same to prepare a standard solution.

[0064] Example 6

[0065] The difference between this embodiment and embodiment 1 is that in step (i), the mass ratio of the furfural standard sample to the methylfurfural standard sample is 5:0.15, and the remaining operations are the same to prepare a standard solution.

[0066] Example 7

[0067] The present embodiment is different from the embodiment 1 in that the mass of the furfural reaction solution in step (iii) is 5.065 g, 5 mL of dichloromethane is added for dilution, and the remaining operations are the same to obtain a standard solution.

[0068] Table 1 Gas chromatography analysis results

[0069] <![CDATA[A1]]> <![CDATA[A2]]> <![CDATA[M1]]> <![CDATA[M2]]> F X Example 1 5102 286494 0.1003 5.0013 1.13 99.3 Example 2 5340 286593 0.1090 5.0030 1.17 98.2 Example 3 5613 290294 0.1008 5.0110 1.04 99.4 Example 4 5019 278488 0.0993 4.9999 1.10 99.2

[0070] The present application provides a method for determining the components of a furfural reaction liquid, which specifically includes the following steps: preparing a standard solution, determining a correction factor using formula 1, and determining the percentage of furfural using formula 2; the present application provides a more suitable quality control method for a novel catalytic reaction for preparing a furfural synthesis process, which can quickly and accurately determine the furfural content in the reaction liquid, better track the reaction process, study the reaction mechanism, and provide a reference basis for in-process control analysis; and the analysis method has high accuracy and good repeatability; the selection of a DB-WAX gas chromatography column, the optimization of chromatographic conditions, and the pretreatment method of the reaction liquid enable baseline separation to be achieved between the compound to be tested and the adjacent components, and the separation of furfural and 5-methylfurfural is better; after the pretreatment of the component to be tested, the interference of miscellaneous peaks is reduced, the interaction force between the component to be tested and the chromatographic column is increased, the peak shape is symmetrical, and the chromatographic peak forward tilt or tailing is reduced.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0072] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for determining the composition of a furfural reaction solution, characterized in that: The specific steps include: (I) Prepare standard solution: Weigh the furfural standard sample and the methyl furfural standard sample respectively, add solvent and make up to volume to prepare standard solution; (II) Determination of correction factor: using a DB-WAX chromatographic column, setting the column temperature, vaporization temperature, detector temperature, nitrogen flow rate, hydrogen flow rate and air flow rate, aspirating the standard solution and injecting it into the chromatograph for analysis, recording the peak areas A1 and A2 of the two compounds in the standard solution; calculating the correction factor F value of methyl furfural according to formula 1: F=(A2*M1) / (A1*M2) Formula 1 Where A1 is the peak area of ​​methyl furfural (cm 2 ), A2 is the peak area of ​​furfural (cm 2 ), M1 is the mass of methylfurfural (g), M2 is the mass of furfural (g); (III) Content determination: Weigh the furfural reaction liquid, pre-treat the furfural reaction liquid to obtain a pre-treated liquid, inject the pre-treated liquid into a chromatograph for analysis, and calculate the furfural percentage content X according to Formula 2; X=(F i *A i ) / [∑(F i *A i )]*100% Formula 2 Where, X is the percentage content (%) of component i in the sample, F i is the correction factor of component i (except methyl furfural, other components are calculated as 1), A i is the peak area of ​​component i (cm 2 ).

2. A method for determining the composition of furfural reaction solution according to claim 1, characterized in that: The mass ratio of the furfural standard sample to the methylfurfural standard sample in step (1) is 5:0.05-0.

15.

3. A method for determining the composition of furfural reaction solution according to claim 1, characterized in that: In step (1), the purity of the furfural standard sample is greater than 99.9%, and the purity of the methylfurfural standard sample is greater than 99.0%.

4. A method for determining the composition of furfural reaction solution according to claim 1, characterized in that: The solvent for the constant volume in step (i) is dichloromethane or chloroform.

5. A method for determining the composition of furfural reaction solution according to claim 1, characterized in that: In step (ii), the column temperature is 148-152°C, the vaporization temperature is 210-230°C, the detector temperature is 215-225°C, the nitrogen flow rate is 20mL / min, the hydrogen flow rate is 25mL / min, and the air flow rate is 135mL / min.

6. A method for determining the composition of furfural reaction solution according to claim 1, characterized in that: The volume of the standard solution injected into the chromatograph in step (ii) is 0.5 μL.

7. A method for determining the composition of furfural reaction solution according to claim 1, characterized in that: The main components of the furfural reaction liquid in step (iii) include: trace corn cobs, furfural, methyl furfural, catalyst, sodium carbonate, methylglyoxal, formaldehyde, glyceraldehyde and ethanolaldehyde.

8. A method for determining the composition of furfural reaction solution according to claim 1, characterized in that: The specific steps of the pretreatment in step (iii) are: weigh 5-7 g of the furfural reaction solution, accurately transfer it to a test tube for dilution, ultrasonicate it, filter it with a microsample filter, and let it stand for 20 minutes.

9. A method for determining the composition of furfural reaction solution according to claim 8, characterized in that: The dilution solvent in step (iii) is dichloromethane or chloroform, and the ratio of the furfural reaction solution to the dilution solvent is 1g:1ml.

10. A method for determining the components of a furfural reaction solution according to claim 1, characterized in that: The volume of the pretreatment solution injected into the chromatograph in step (iii) is 0.5 μL.

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