A gas phase detection method for the content of ketone in acetylene glycol polyoxyethylene propylene ether

Abstract

The invention discloses a gas phase detection method for the content of ketone in an acetylene glycol polyoxyethylene propylene ether, comprising the following steps: (1) preparation of an external standard solution, using 4-methyl-2-pentanone / 5-methyl-2-hexanone standard products, and preparing a series of standard solutions of different concentrations with DMF; (2) sample solution preparation, weighing the sample to be tested, diluting it with DMF, and shaking it to obtain a sample solution; (3) headspace balance, absorbing the above-mentioned standard solution and sample solution, and fully balancing them on a headspace sampler according to the set headspace balance conditions; (4) using a gas chromatograph for measurement, and drawing a standard curve of concentration-peak area. (5) according to the standard curve and the peak area of ​​the sample detection, the content of 4-methyl-2-pentanone or 5-methyl-2-hexanone in the sample is detected. The method of the present invention has the characteristics of good separation effect, good method repeatability, simple operation, etc., and can quickly, accurately and efficiently realize the gas phase detection of the ketone content in the acetylene glycol polyoxyethylene ether.

Description

Technical Field

[0001] The invention relates to the technical field of content detection, and in particular to a gas phase detection method for ketone content in acetylene glycol polyoxyethylene ether. Background Art

[0002] At present, the catalysts for synthesizing acetylene glycol polyoxyethylene ether are mainly alkaline catalysts and acidic catalysts, among which alkaline catalysts include inorganic alkaline catalysts such as potassium hydroxide and organic alkaline catalysts such as triethylamine. In the reaction process of acetylene glycol and ethylene oxide, insufficient base strength will make it difficult to catalyze the continuous reaction; increased base strength will cause acetylene glycol to decompose to varying degrees during the reaction. 4-Methyl-2-pentanone will be produced during the synthesis of 2,4,7,9-tetramethyl-5-decyne-4,7-diol polyoxyethylene ether, and 5-methyl-2-hexanone will be produced during the synthesis of 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol polyoxyethylene ether. 4-Methyl-2-pentanone and 5-methyl-2-hexanone have adverse effects on the odor and quality of acetylene glycol polyoxyethylene ether products, so it is necessary to detect their content by quantitative detection means.

[0003] At present, there is no national standard or patented detection method for the ketone content in acetylene glycol polyoxyethylene ethers. Other detection methods such as nuclear magnetic resonance and mass spectrometry are not applicable because most production enterprises do not have them due to the relatively expensive instruments and equipment. In addition, since 2,4,7,9-tetramethyl-5-decyne-4,7-diol polyoxyethylene ether and 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol polyoxyethylene ether are epoxy addition polymers, the product boiling point is relatively high and is not suitable for direct gas phase injection for detection. Therefore, it is an urgent problem to be solved by those skilled in the art to establish a gas phase detection method for the ketone content in acetylene glycol polyoxyethylene ethers that is simple to operate, fast, accurate and efficient. Summary of the invention

[0004] A gas phase detection method for ketone content in acetylene glycol polyoxyethylene ether can realize gas phase detection of ketone content in acetylene glycol polyoxyethylene ether quickly, accurately and efficiently.

[0005] To achieve the above object, the present invention is implemented by the following technical scheme: A gas phase detection method for ketone content in acetylene glycol polyoxyethylene ether, characterized in that it comprises the following steps:

[0006] (1) Preparation of standard solution: using 4-methyl-2-pentanone / 5-methyl-2-hexanone standard, a series of standard solutions of different concentrations were prepared in DMF;

[0007] (2) Sample solution preparation: weigh the sample to be tested, dilute it with DMF, and shake well to obtain a sample solution;

[0008] (3) Headspace balance: aspirate the above standard solution and sample solution and fully balance them on the headspace injector according to the set headspace balance conditions.

[0009] (4) On-machine testing: The above-mentioned fully balanced standard solution and sample solution are measured by gas chromatograph, and a concentration-peak area standard curve is drawn. The gas chromatography detection conditions are:

[0010] Chromatographic column: Equivalent chromatographic column with highly polar polyethylene glycol (PEG) as stationary phase;

[0011] Inlet Temperature: 200~300℃;

[0012] Detector Temperature: 200~300℃;

[0013] Oven Temperature: Initial temperature 50°C, program temperature increase;

[0014] The carrier gas is high-purity nitrogen with a purity of ≥99.999%, a flow rate of 2 ml / min, and a split ratio of 5:1 to 20:1;

[0015] In the above scheme: the concentrations of the prepared external standard solutions of 4-methyl-2-pentanone or 5-methyl-2-hexanone of different concentrations are 5000 mg / L, 3000 mg / L, 1000 mg / L, 500 mg / L, and 100 mg / L.

[0016] In the above scheme: the sample solution is prepared by taking 5 g of sample into a 10 ml volumetric flask, adding DMF to dilute to the scale, and shaking well.

[0017] In the above scheme: the head space sampler is the HS930 head space sampler of Zhejiang Fuli, and the temperature control range is 5-200°C.

[0018] In the above scheme: the headspace equilibrium conditions are: equilibrium temperature: 70°C to 95°C, equilibrium time: 30min to 40min.

[0019] In the above scheme: the column box program heating conditions are: initial temperature 50°C, hold for 5 minutes, increase to 100°C at a rate of 4°C / min, do not hold, continue to increase to 200°C at a rate of 30°C / min, and hold for 1 minute.

[0020] In the above scheme: the gas chromatography detector adopts a hydrogen flame ionization detector FID.

[0021] In the above scheme: the chromatographic column is an Agilent CP-Wax52CB chromatographic column or other equivalent chromatographic columns, and the specifications of the capillary column are: 30m×0.32mm×0.25μm.

[0022] In the above scheme: the injection volume of the gas phase detection method is to accurately transfer 1.00 mL of the prepared standard solution and sample solution into the headspace injection bottle.

[0023] According to the above chromatographic conditions, the sample is automatically injected, the peak area of ​​each component is recorded, and the standard curve is drawn according to the relationship between the external standard solution concentration and the peak area to obtain the linear regression equation. Then the peak area of ​​the sample solution to be tested is brought into the current regression equation to calculate the ketone content in the sample solution to be tested. The calculation formula is as follows:

[0024] The calculation formula of ketone content in the sample solution to be tested is:

[0025]

[0026] A i - The corresponding peak area of ​​ketone in the test sample solution;

[0027] W 外 -Concentration of 4-methyl-2-pentanone / 5-methyl-2-hexanone in the external standard solution, mg / L;

[0028] A 外 -Peak area of ​​4-methyl-2-pentanone / 5-methyl-2-hexanone in external standard solution;

[0029] W i - Ketone content in the sample solution to be tested, mg / L;

[0030] The present invention has the following beneficial effects:

[0031] The invention provides a gas phase detection method for ketone content in acetylene glycol polyoxyethylene ether. The method comprises the following steps: selecting an Agilent CP-Wax52CB chromatographic column according to the properties of a sample, performing balancing through a headspace injector, ensuring that 4-methyl-2-pentanone / 5-methyl-2-hexanone and low-boiling point components in the sample are completely vaporized, and then effectively separating the components through programmed temperature increase and a suitable carrier gas flow rate. The sample can be detected in about 12 minutes, and content analysis is performed according to a peak area result. The method can quickly, accurately and efficiently determine the content of 4-methyl-2-pentanone / 5-methyl-2-hexanone, has a stable baseline without tailing, a good peak shape, low instrument operation cost, a simple and convenient detection process, good repeatability, and provides a reference for a production process.

[0032] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description in combination with the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0034] Figure 1 This is a spectrum of a 4-methyl-2-pentanone standard solution detected by an Agilent CP-Wax52CB capillary column in the present invention;

[0035] Figure 2 The present invention uses an Agilent CP-Wax52CB capillary column to detect low-boiling point components and 4-methyl-2-pentanone in the sample to be tested;

[0036] Figure 3 It is the working curve spectrum of the 4-methyl-2-pentanone standard solution of the present invention;

[0037] Figure 4 This is the detection spectrum of the 5-methyl-2-hexanone standard solution detected by the Agilent CP-Wax52CB capillary column of the present invention;

[0038] Figure 5 The present invention adopts Agilent CP-Wax52CB capillary column to detect low boiling point components and 5-methyl-2-hexanone in the sample to be tested;

[0039] Figure 6 It is the working curve spectrum of the standard solution of 5-methyl-2-hexanone of the present invention. DETAILED DESCRIPTION

[0040] The specific implementation modes of the present invention are described in detail below, which are a part of this specification. The principles of the present invention are explained through examples. Other aspects, features and advantages of the present invention will become clear through the detailed description.

[0041] A gas phase detection method for ketone content in acetylene glycol polyoxyethylene ether, the specific method is as follows:

[0042] Example 1 Gas Phase Detection of the Content of 4-Methyl-2-Pentanone in 2,4,7,9-Tetramethyl-5-Decyne-4,7-diol Polyoxyethylene Ether

[0043] Instruments and reagents: Gas chromatograph (Agilent GC8860); electronic balance (Mettler Toledo

[0044] ME204); Agilent CP-Wax52CB chromatographic column (30m×0.32mm×0.25μm), DMF was chromatographically pure; 4-methyl-2-pentanone (AR).

[0045] 1. Headspace sampler equilibrium conditions: 70℃, equilibrium for 30min.

[0046] 2. Gas chromatography detection conditions

[0047] Chromatographic column: Agilent CP-Wax52CB chromatographic column, capillary column specifications: 30m×0.32mm×0.25μm.

[0048] Inlet Temperature: 200°C

[0049] Detector Temperature: 280°C

[0050] Heating program (Oven Ramp): Initial temperature 50℃, hold for 5 min, increase to 100℃ at a rate of 4℃ / min, do not hold, continue to increase to 200℃ at a rate of 30℃ / min, hold for 1 min;

[0051] The carrier gas is high-purity nitrogen with a purity of ≥99.999%, a flow rate of 2 ml / min, and a split ratio of 5:1.

[0052] The injection volume is to accurately transfer 1.00 mL of the prepared standard solution and sample solution into the headspace injection bottle.

[0053] 3. Solution Preparation

[0054] Preparation of 4-methyl-2-pentanone standard stock solution: weigh 1.0 g of 4-methyl-2-pentanone into a 100 ml volumetric flask, add DMF to dilute to the mark, and shake well;

[0055] Then prepare the 4-methyl-2-pentanone standard stock solution into the following concentrations: 5000 mg / L, 3000 mg / L, 1000 mg / L, 500 mg / L, and 100 mg / L.

[0056] 4. Standard curve drawing

[0057] According to the above chromatographic conditions, the peak area of ​​4-methyl-2-pentanone standard solution was detected, and the linear regression equation was obtained: y = 1.3277x-24.334, and the linear correlation coefficient R2 = 0.9997. Figure 3 shown.

[0058] Standard solution concentration (mg / L) 101.33 506.65 1013.3 3039.9 5066.5 Peak area 133.72 631.84 1320.26 3932.10 6751.75

[0059] 5. Peak time of each component of the present invention

[0060] Sample composition 4-Methyl-2-pentanone DMF(Solvent) Relative peak time 3.1 13.0

[0061] 6. Sample testing

[0062] Prepare the sample solution: weigh 5 g of the sample into a 10 ml volumetric flask, add DMF to dilute to the mark, and shake well.

[0063] According to the above chromatographic conditions, the sample solution to be tested was injected twice, the peak area of ​​4-methyl-2-pentanone was recorded and averaged, and the average value was substituted into the standard curve formula to calculate the content of 4-methyl-2-pentanone in the test sample solution.

[0064] Sample No. Sample weight / g Sample dilution volume / mL Peak area Ketone concentration in sample solution (mg / L) 1 5.0000 10.0 3373.31 2559.04 2 5.0000 10.0 3367.19 2530.69 Mean 5.0000 10.0 3370.25 2544.87

[0065] Example 2 Gas Phase Detection of 5-Methyl-2-Hexanone Content in 2,5,8,11-Tetramethyl-6-Dodecyne-5,8-Diol Polyoxyethylene Ether

[0066] The instruments and reagents used were: gas chromatograph (Agilent GC8860); electronic balance (Mettler Toledo ME204); Agilent CP-Wax52CB chromatographic column (30m×0.32mm×0.25μm), DMF of chromatographic grade; 5-methyl-2-hexanone (AR).

[0067] 1. Headspace sampler equilibrium conditions: 95°C, equilibrium for 40 min.

[0068] 2. Gas chromatography detection conditions

[0069] Chromatographic column: Agilent CP-Wax52CB chromatographic column, capillary column specifications: 30m×0.32mm×0.25μm.

[0070] Inlet Temperature: 260°C

[0071] Detector Temperature: 300°C

[0072] Heating program (Oven Ramp): Initial temperature 50℃, hold for 5 min, increase to 100℃ at a rate of 4℃ / min, do not hold, continue to increase to 200℃ at a rate of 30℃ / min, hold for 1 min;

[0073] The carrier gas is high-purity nitrogen with a purity of ≥99.999%, a flow rate of 2 ml / min, and a split ratio of 5:1.

[0074] The injection volume is to accurately transfer 1.00 mL of the prepared standard solution and sample solution into the headspace injection bottle.

[0075] 3. Solution preparation

[0076] Preparation of 5-methyl-2-hexanone standard stock solution: weigh 1.0 g of 5-methyl-2-hexanone into a 100 ml volumetric flask, add DMF to dilute to the mark, and shake well;

[0077] Then the 5-methyl-2-hexanone standard stock solution was prepared into: 5000 mg / L, 3000 mg / L, 1000 mg / L, 500 mg / L, 100 mg / L.

[0078] 4. Standard curve drawing

[0079] According to the above chromatographic conditions, the peak area of ​​5-methyl-2-hexanone standard solution was detected, and the linear regression equation was obtained: y = 1.2618x-11.937, and the linear correlation coefficient R2 = 0.9995. Figure 3 shown.

[0080] Standard solution concentration (mg / L) 103.47 517.35 1034.7 3104.1 5173.5 Peak area 141.96 663.80 1390.37 3887.73 6252.71

[0081] 5. Peak time of each component of the present invention

[0082] Sample composition 5-Methyl-2-hexanone DMF(Solvent) Relative peak time 5.8 13.0

[0083] 6. Sample testing

[0084] Prepare the sample solution: weigh 5 g of the sample into a 10 ml volumetric flask, add DMF to dilute to the mark, and shake well.

[0085] According to the above chromatographic conditions, the sample solution to be tested was injected twice, the peak area of ​​5-methyl-2-hexanone was recorded and averaged, and the average value was substituted into the standard curve formula to calculate the content of 5-methyl-2-hexanone in the test sample solution.

[0086] Sample No. Sample weight / g Sample dilution volume / mL Peak area Ketone concentration in sample solution (mg / L) 1 5.0000 10.0 4705.16 3738.39 2 5.0000 10.0 4996.50 3969.28 Mean 5.0000 10.0 4850.83 3853.835

[0087] The raw materials listed in the present invention, as well as the upper and lower limits and interval values ​​of the raw materials of the present invention, and the upper and lower limits and interval values ​​of the process parameters (such as temperature, time, etc.) can all realize the present invention, and the embodiments are not listed one by one here.

[0088] The above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principle of the present invention, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims

1. A gas phase detection method for the content of ketones in acetylene glycol polyoxyethylene ethers, wherein the acetylene glycol polyoxyethylene ethers include 2,4,7,9-tetramethyl-5-decyne-4,7-diol polyoxyethylene ether and 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol polyoxyethylene ether, characterized in that: The steps include: (1) Preparation of external standard solution: using 4-methyl-2-pentanone / 5-methyl-2-hexanone standard, a series of standard solutions of different concentrations were prepared in DMF; (2) Sample solution preparation: weigh the sample to be tested, dilute it with DMF, and shake well to obtain a sample solution; (3) Headspace balance: aspirate the above standard solution and sample solution, and fully balance them on the headspace injector according to the set headspace balance conditions; (4) On-machine testing: The above-mentioned fully balanced standard solution and sample solution are measured by gas chromatograph, and a concentration-peak area standard curve is drawn. The gas chromatography detection conditions are: Chromatographic column: Equivalent chromatographic column with highly polar polyethylene glycol (PEG) as stationary phase; Inlet Temperature: 200~300℃; Detector Temperature: 200~300℃; Oven Temperature: Initial temperature 50°C, program temperature increase; The carrier gas is high-purity nitrogen with a purity of ≥99.999%, a flow rate of 2 ml / min, and a split ratio of 5:1 to 20:

1.

2. The gas phase detection method for the content of ketone in the acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: The concentrations of the external standard solutions of 4-methyl-2-pentanone or 5-methyl-2-hexanone of different concentrations prepared in step (1) are 5000 mg / L, 3000 mg / L, 1000 mg / L, 500 mg / L, and 100 mg / L.

3. The gas phase detection method for the content of ketone in the acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: The sample solution prepared in step (2) is prepared by taking 5 g of sample into a 10 ml volumetric flask, adding DMF to dilute to the scale, and shaking well.

4. The gas phase detection method for the content of ketone in the acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: The head space sampler in step (3) is the HS930 head space sampler produced by Zhejiang Fuli, and the temperature control range is 5 to 200°C.

5. The gas phase detection method for the content of ketone in the acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: In step (3), the headspace equilibrium conditions are: equilibrium temperature: 70°C to 95°C, equilibrium time: 30min to 40min.

6. The gas phase detection method for the content of ketone in acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: The column box temperature program conditions are as follows: initial temperature 50°C, maintained for 5 minutes, increased to 100°C at a rate of 4°C / min, not maintained, continued to increase to 200°C at a rate of 30°C / min, and maintained for 1 minute.

7. The gas phase detection method for the content of ketone in acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: The gas chromatography detector adopts a hydrogen flame ionization detector FID.

8. The gas phase detection method for the content of ketone in acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: The chromatographic column is an Agilent CP-Wax52CB chromatographic column.

9. The gas phase detection method for the content of ketone in acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: Specifications of the capillary column: 30m×0.32mm×0.25μm.

10. The gas phase detection method for the content of ketone in acetylene glycol polyoxyethylene propylene ether according to claim 1, characterized in that: The injection method is to accurately transfer 1.00 mL into the headspace injection vial.

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