Method for detecting contents of toluene and chlorobenzene in 4, 4 '-dichlorodiphenyl sulfone

Abstract

The invention relates to the technical field of chemical analysis, and particularly discloses a method for detecting the content of methylbenzene and chlorobenzene in 4, 4 '-dichlorodiphenyl sulfone. According to the method for detecting the content of toluene and chlorobenzene in 4, 4 '-dichlorodiphenyl sulfone, provided by the invention, the content of toluene and chlorobenzene in 4, 4'-dichlorodiphenyl sulfone is detected by adopting a gas chromatographic method, taking a chromatographic column taking 5% phenyl-95% dimethyl polysiloxane as a stationary liquid as a detection chromatographic column and cooperating with a specific programmed heating mode and specific gas chromatographic conditions such as sample inlet temperature, detector temperature and split ratio. The method realizes simultaneous quantitative detection of toluene and chlorobenzene in 4, 4 '-dichlorodiphenyl sulfone, makes up for the blank in the prior art that the content of chlorobenzene and toluene in 4, 4'-dichlorodiphenyl sulfone cannot be effectively detected, and is beneficial to realizing quality control of 4, 4 '-dichlorodiphenyl sulfone products, so as to control the quality of 4, 4'-dichlorodiphenyl sulfone. The quality of 4, 4 '-dichlorodiphenyl sulfone and downstream products can be effectively guaranteed, and the consistency and stability of the quality of the downstream products can be guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of chemical analysis, and in particular to a method for detecting the contents of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone. Background Art

[0002] 4,4'-Dichlorodiphenyl sulfone (DDS), also known as 4,4'-dichlorobisphenyl sulfone and di-p-chlorophenyl sulfone, has a molecular formula of C 12 H8Cl2O2S, relative molecular mass 287.2, appearance is white monoclinic crystals, melting point 147℃-149℃, can sublime, relative density 1.54, insoluble in water, slightly soluble in cold ethanol.

[0003] 4,4′-Dichlorodiphenyl sulfone is mainly used as an intermediate for polysulfone engineering plastics. A small amount is used as a raw material for the production of 4,4′-diaminodiphenyl sulfone, a drug for the treatment of leprosy. It is a fine chemical product with high development prospects and an intermediate for medicines, dyes and pesticides. 4,4′-Dichlorodiphenyl sulfone has broad application prospects in the fields of engineering plastics and fine chemicals. With the development of engineering plastics polysulfone and polyarylethersulfone, the demand for 4,4′-dichlorodiphenyl sulfone will continue to increase, and the market prospects are good.

[0004] At present, the synthesis of 4,4′-dichlorodiphenyl sulfone mainly uses chlorobenzene as raw material and toluene as purification method. Chlorobenzene and toluene are two benzene solvents with high toxicity, and toluene is a first-level environmental management substance. The residues of chlorobenzene and toluene will have a potential impact on the quality and safety of 4,4′-dichlorodiphenyl sulfone products. However, there is currently no detection method for chlorobenzene and toluene in 4,4′-dichlorodiphenyl sulfone. Therefore, in order to control the content of chlorobenzene and toluene in 4,4′-dichlorodiphenyl sulfone to ensure the quality and safety of 4,4′-dichlorodiphenyl sulfone, it is necessary to provide a detection method that can effectively determine the content of chlorobenzene and toluene in 4,4′-dichlorodiphenyl sulfone. Summary of the invention

[0005] Aiming at the technical problem that there is a lack of effective detection of the contents of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone in the prior art, the present invention provides a method for detecting the contents of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0007] A method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone, the detection method is a gas chromatography method, comprising the following steps:

[0008] (1) Preparation of test solution and mixed reference solution:

[0009] Preparation of mixed reference solution: Take toluene and chlorobenzene reference substances and prepare a mixed reference solution with acetonitrile;

[0010] Preparation of test solution: Take a sample of 4,4′-dichlorodiphenyl sulfone and prepare a test solution with acetonitrile;

[0011] (2) Take the mixed reference solution and test solution and perform the test under the following gas chromatography conditions:

[0012] Detector: Hydrogen flame ionization detector;

[0013] Chromatographic column: 5% phenyl-95% dimethyl polysiloxane as the stationary liquid;

[0014] Column temperature: 60℃-70℃, maintain for 2min-4min, then increase the temperature to 125℃-135℃ at a rate of 14℃ / min-16℃ / min, maintain for 2min-3min, then increase the temperature to 145℃-155℃ at a rate of 9℃ / min-11℃ / min, maintain for 2min-3min, and finally increase the temperature to 295℃-305℃ at a rate of 28℃ / min-32℃ / min, maintain for 8min-12min;

[0015] Inlet temperature: 245℃-255℃;

[0016] Detector temperature: 295℃-305℃;

[0017] Split ratio: 48-52:1.

[0018] Compared with the prior art, the method for detecting the contents of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone provided by the invention adopts gas chromatography, uses a chromatographic column with 5% phenyl-95% dimethylpolysiloxane as a stationary liquid as a detection chromatographic column, cooperates with a specific programmed temperature rising mode and specific gas chromatography conditions such as injection port temperature, detector temperature and split ratio, thereby realizing simultaneous quantitative detection of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone, is more conducive to reflecting the quality of 4,4'-dichlorodiphenyl sulfone, and is of great significance for establishing a quality control system for 4,4'-dichlorodiphenyl sulfone and ensuring the product quality and safety thereof.

[0019] Furthermore, the method for detecting the contents of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone provided by the present invention has been verified by methodology to be highly specific, good in accuracy, sensitivity, repeatability and stability, and simple to operate, and can achieve qualitative and quantitative analysis of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone through one detection, thus filling the gap that the prior art cannot effectively detect the contents of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone, and is conducive to achieving quality control of 4,4'-dichlorodiphenyl sulfone products, thereby providing effective guarantee for controlling the quality of 4,4'-dichlorodiphenyl sulfone and downstream products, and is conducive to ensuring the consistency and stability of the quality of downstream products.

[0020] Preferably, the chromatographic column is Wonda Cap5, 30m×0.32mm×0.25μm.

[0021] Preferably, the column temperature is: maintained at 65°C for 3 min, then increased to 130°C at a rate of 15°C / min, maintained for 2 min, then increased to 150°C at a rate of 10°C / min, maintained for 2 min, and finally increased to 300°C at a rate of 30°C / min, maintained for 10 min.

[0022] The preferred programmed temperature rising method combined with a specific chromatographic column can make the peak shapes of 4,4'-dichlorodiphenyl sulfone, chlorobenzene and toluene good, and is conducive to improving the separation between the components, thereby achieving qualitative and quantitative analysis of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone.

[0023] Preferably, the injection port temperature is 250°C.

[0024] Preferably, the detector temperature is 300°C.

[0025] Preferably, the split ratio is 50:1.

[0026] Preferably, the carrier gas is nitrogen with a flow rate of 2.8 mL / min-3.2 mL / min.

[0027] More preferably, the carrier gas flow rate is 3.0 mL / min.

[0028] Preferably, the injection volume is 1.0 μL.

[0029] Preferably, the concentration of chlorobenzene in the mixed reference solution is 34.3 mg / mL, and the concentration of toluene is 40.7 mg / mL.

[0030] Preferably, the concentration of the test solution is 40 mg / mL.

[0031] The preferred gas chromatography conditions are conducive to the full detection of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone, and the accurate quantitative detection of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone.

[0032] The gas chromatography detection method provided by the present invention can realize the effective detection of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone, and through methodological research and verification, it is proved that the method of the present invention has good sensitivity, accuracy and reproducibility, which makes up for the blank that the prior art cannot realize the effective detection of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone, is conducive to timely monitoring of the synthesis process of 4,4'-dichlorodiphenyl sulfone, so as to ensure the quality of downstream products, and the whole operation process is reliable and controllable, suitable for practical application and promotion, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the chromatogram of the mixed reference solution under the system suitability item in Example 2;

[0034] Figure 2 The chromatogram is the mixed reference solution in Comparative Example 3. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Example 1

[0037] 1.1 Instruments and reagents

[0038] GC-2014C gas chromatograph (Shimadzu Corporation, Japan), hydrogen flame ionization detector, Labsolutions chromatography workstation (Shimadzu Corporation, Japan), autosampler (Shimadzu Corporation, Japan).

[0039] Wonda Cap5 capillary column (5% phenyl-95% dimethylpolysiloxane); toluene and chlorobenzene were of premium grade; acetonitrile was of chromatographic grade.

[0040] 1.2 Solution preparation:

[0041] Blank solvent: acetonitrile.

[0042] Preparation of mixed reference solution: Accurately measure 1 mL (0.8572 g) of toluene and 1 mL (1.1075 g) of chlorobenzene in a 25 mL volumetric flask, and make up to volume with acetonitrile to prepare the mixed reference solution.

[0043] Preparation of the test solution: Accurately weigh 1.0 g of 4,4′-dichlorodiphenyl sulfone sample and place it in a 25 mL volumetric flask, add acetonitrile, sonicate until the sample is completely dissolved, and adjust the volume to obtain the test solution.

[0044] 1.2 Gas chromatography conditions:

[0045] Detector: Hydrogen flame ionization (FID) detector;

[0046] Chromatographic column: Wonda Cap5, 30m×0.32mm×0.25μm;

[0047] Column temperature: 65℃ for 3 min, then increase the temperature to 130℃ at a rate of 15℃ / min, maintain for 2 min, then increase the temperature to 150℃ at a rate of 10℃ / min, maintain for 2 min, and finally increase the temperature to 300℃ at a rate of 30℃ / min, maintain for 10 min;

[0048] Inlet temperature: 250°C;

[0049] Detector temperature: 300°C;

[0050] Carrier gas: high-purity nitrogen (purity 99.99%), flow rate 3.0 mL / min;

[0051] Split ratio: 50:1;

[0052] Injection volume: 1.0 μL.

[0053] Example 2

[0054] Methodological validation:

[0055] 2.1 System Applicability

[0056] Take blank solvent and the mixed reference solution and test them according to the above gas chromatography conditions, record the chromatogram, and the chromatogram of the mixed reference solution is as follows: Figure 1 shown.

[0057] Depend on Figure 1 It can be seen that the elution time of acetonitrile is 3.63 min, the elution time of toluene is 5.05 min, and the elution time of chlorobenzene is 6.13 min. The theoretical plate numbers are all greater than 5000, and the separation degrees are all greater than 5. In the detection method provided by the present invention, the blank solvent does not interfere with the detection of each component, and the separation degree between each component meets the requirements, indicating that the method has good specificity.

[0058] 2.2 Repeatability

[0059] Accurately weigh 0.4286 g of toluene and 0.5538 g of chlorobenzene in a 25 mL volumetric flask, and adjust the volume with acetonitrile to obtain a control solution 1 with a toluene concentration of 17.14 mg / mL and a chlorobenzene concentration of 22.15 mg / mL. Pipette 1 mL from control solution 1 into a 250 mL volumetric flask, adjust the volume with acetonitrile, and obtain control solution 2. Pipette 1 mL from control solution 2 into a 10 mL volumetric flask, adjust the volume with acetonitrile, and obtain a control solution 3 with a toluene concentration of 6.86 mg / mL and a chlorobenzene concentration of 8.86 mg / mL.

[0060] The control solution 1 and the control solution 3 were injected 5 times continuously, and the RSD of the peak areas at different concentrations was calculated. The results are shown in Table 1.

[0061] Table 1 Repeatability test results

[0062]

[0063] The test results show that the results of five consecutive tests of samples with the same concentration are basically consistent, indicating that this method has good repeatability.

[0064] 2.3 Linear range

[0065] Accurately weigh 0.8572 g of toluene and 1.1075 g of chlorobenzene into a 25 mL volumetric flask, and make up to volume with acetonitrile to obtain control solution 1.

[0066] Pipette 1 mL of control solution 1 into a 250 mL volumetric flask and dilute to volume with acetonitrile to obtain control solution 2.

[0067] From control solution 2, 1.0mL, 0.8mL, 0.6mL, 0.4mL, 0.2mL, and 0.1mL were respectively transferred into a 25mL volumetric flask, and the volume was adjusted with acetonitrile to obtain a series of control solutions with toluene contents of 5.504μg / mL, 4.404μg / mL, 3.302μg / mL, 2.202μg / mL, 1.101μg / mL, and 0.5504μg / mL; and chlorobenzene contents of 7.088μg / mL, 5.670μg / mL, 4.252μg / mL, 2.836μg / mL, 1.416μg / mL, and 0.709μg / mL.

[0068] Accurately measure 1.0 μL of the above series of reference solution respectively, inject and detect according to the above gas chromatography conditions, record the chromatogram, determine the peak area, and draw a linear regression curve with concentration (μg / mL) as the horizontal axis and peak area as the vertical axis.

[0069] The linear equation of toluene is y = 0.0032x + 0.1012, R 2 =0.9996; the linear equation of chlorobenzene is y=0.0042x+0.0152, R2 =0.9999.

[0070] The above results show that the linear relationship between the components is good, R 2 All of them are greater than 0.999, indicating that the method provided by the present invention has a good linear relationship.

[0071] 2.4 Limit of detection and limit of quantification

[0072] Accurately pipette 10.0mL, 5.0mL, 4.0mL, 3.0mL, 2.0mL, 1.0mL, and 0.5mL of the control solution 3 under item 2.2 into a 25mL volumetric flask, add acetonitrile and shake to volume to obtain a series of reference solutions with toluene concentrations of 2.744μg / mL, 1.372μg / mL, 1.098μg / mL, 0.8232μg / mL, 0.5488μg / mL, and 0.2744μg / mL, and chlorobenzene concentrations of 3.544μg / mL, 1.772μg / mL, 1.4176μg / mL, 1.0632μg / mL, 07088μg / mL, and 0.3544μg / mL.

[0073] Accurately measure each of the above-mentioned reference substance solutions, perform serial dilutions, inject them into the gas chromatograph respectively, record the chromatogram, and the results are shown in Table 2.

[0074] Table 2

[0075] Serial number Toluene concentration μg / mL Toluene peak area Chlorobenzene concentration μg / mL Chlorobenzene peak area 1 2.744 705 3.544 718 2 1.372 342 1.772 351 3 1.098 275 1.4176 284 4 0.8232 210 1.0632 209 5 0.5488 64 0.7088 142 6 0.2744 Not detected 0.3544 Not detected

[0076] The first five points of toluene R 2 =0.987Chlorobenzene R 2 =0.977 does not meet the linear requirements. The first four points are toluene R 2 =0.9996, Chlorobenzene R 2 =0.9999, toluene linear regression equation: Y=0.0039X+0.0334, chlorobenzene linear regression equation: Y=0.0049X+0.0446.

[0077] The concentration corresponding to the zero intersection of the linear regression equation was taken as the detection limit. The results of the quantification limit and detection limit are shown in Table 3.

[0078] Table 3 Limit of quantitation and detection limit

[0079]

[0080] 2.4 Recovery rate

[0081] Take 2 batches of 4,4′-dichlorodiphenyl sulfone samples, weigh 1.0g of 4,4′-dichlorodiphenyl sulfone sample to determine the toluene and chlorobenzene content. Then, accurately weigh 1.0g of each batch of samples and add them to three 25mL volumetric flasks, add 0.8mL, 1.0mL, and 1.2mL of the control solution 3 under item 2.2 to each volumetric flask, add acetonitrile to the volume, and use it as the recovery spike test solution.

[0082] The above 9 portions of the recovery spiked test solution were tested respectively according to the above gas chromatography conditions, the chromatograms were recorded, and the recovery rates were calculated. The results are shown in Table 4.

[0083] Table 4 Recovery test results

[0084]

[0085]

[0086] The test results show that the recovery rate of each component is between 95% and 105%, indicating that the method provided by the present invention has good accuracy.

[0087] Comparative Example 1

[0088] This comparative example provides a method for detecting the content of chlorobenzene and toluene in 4,4′-dichlorodiphenyl sulfone, which is different from Example 1 only in that the solvent for preparing the test solution and the reference solution is ethyl acetate.

[0089] 1.0 g of 4,4′-dichlorodiphenyl sulfone sample was weighed and added to 25 mL of ethyl acetate solvent. It was found that the product was insoluble and the toluene and chlorobenzene contents could not be detected.

[0090] Comparative Example 2

[0091] This comparative example provides a method for detecting the content of chlorobenzene and toluene in 4,4'-dichlorodiphenyl sulfone, using the high performance liquid chromatography method for the determination of diphenyl and 4,4'-dichlorodiphenyl sulfone in SNT2810-2011 food contact materials and polymer materials.

[0092] Through experiments, the HPLC method was used to determine toluene and chlorobenzene. The peak times of toluene and chlorobenzene were 7.41min and 7.62min respectively. When toluene and chlorobenzene existed at the same time, the two peaks overlapped and the detection sensitivity was low. Toluene and chlorobenzene did not absorb well under the wavelength of 235-250nm. When the toluene content was less than 1000ppm, it was not detected. It is not suitable for the detection of chlorobenzene and toluene content in 4,4′-dichlorodiphenyl sulfone.

[0093] Comparative Example 3

[0094] This comparative example provides a method for detecting the content of chlorobenzene and toluene in 4,4′-dichlorodiphenyl sulfone, and the chromatographic conditions are as follows:

[0095] Chromatographic column: DB-624 capillary column (6% propylphenyl-94% dimethylpolysiloxane, 30m*0.53mm, 3m);

[0096] Program temperature rise: initial temperature 50℃, maintain for 3 min, then increase to 130℃ at a rate of 20℃ / min, maintain for 20 min.

[0097] Detector temperature: 200°C;

[0098] Inlet temperature: 180°C;

[0099] Carrier gas: high-purity nitrogen, column flow rate: 5 mL / min, tail gas: 20 mL / min;

[0100] Headspace bottle equilibrium temperature: 60℃;

[0101] Equilibration time: 30 min;

[0102] Injection volume: 0.5mL.

[0103] Take the mixed reference solution in Example 1 for testing, and the detection chromatogram is as follows: Figure 2 As shown in the figure, it can be seen that the separation degree and theoretical plate number of toluene and chlorobenzene are not up to standard, and it is impossible to accurately detect the content of chlorobenzene and toluene in 4,4′-dichlorodiphenyl sulfone.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone, characterized in that: The detection method is gas chromatography, comprising the following steps: (1) Preparation of test solution and mixed reference solution: Preparation of mixed reference solution: Take toluene and chlorobenzene reference substances and prepare a mixed reference solution with acetonitrile; Preparation of test solution: Take a sample of 4,4'-dichlorodiphenyl sulfone and prepare a test solution with acetonitrile; (2) Take the mixed reference solution and test solution and perform the test under the following gas chromatography conditions: Detector: Hydrogen flame ionization detector; Chromatographic column: 5% phenyl-95% dimethyl polysiloxane as the stationary liquid; Column temperature: 60℃-70℃, maintain for 2min-4min, then increase the temperature to 125℃-135℃ at a rate of 14℃ / min-16℃ / min, maintain for 2min-3min, then increase the temperature to 145℃-155℃ at a rate of 9℃ / min-11℃ / min, maintain for 2min-3min, and finally increase the temperature to 295℃-305℃ at a rate of 28℃ / min-32℃ / min, maintain for 8min-12min; Inlet temperature: 245℃-255℃; Detector temperature: 295℃-305℃; Split ratio: 48-52:

1.

2. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone according to claim 1, characterized in that: The chromatographic column is Wonda Cap5, 30m×0.32mm×0.25μm.

3. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone as claimed in claim 1, characterized in that: The column temperature is: 65°C for 3 min, then increased to 130°C at a rate of 15°C / min, maintained for 2 min, then increased to 150°C at a rate of 10°C / min, maintained for 2 min, and finally increased to 300°C at a rate of 30°C / min, maintained for 10 min.

4. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone as claimed in claim 1, characterized in that: The injection port temperature was 250 °C and the detector temperature was 300 °C.

5. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone as claimed in claim 1, characterized in that: The split ratio is 50:

1.

6. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone according to claim 1, characterized in that: The carrier gas was nitrogen with a flow rate of 2.8 mL / min-3.2 mL / min.

7. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone according to claim 6, characterized in that: The carrier gas flow rate was 3.0 mL / min.

8. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone as claimed in claim 1, characterized in that: The injection volume was 1.0 μL.

9. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone according to claim 1, characterized in that: The concentration of chlorobenzene in the mixed reference solution was 34.3 mg / mL, and the concentration of toluene was 40.7 mg / mL.

10. The method for detecting the content of toluene and chlorobenzene in 4,4'-dichlorodiphenyl sulfone according to claim 1, characterized in that: The concentration of the test solution is 40 mg / mL.

Images