CN110187026A - A kind of analysis method of 2- propyl enanthol and its impurity - Google Patents

Abstract

The invention discloses a method for analyzing 2-propyl heptanol and impurities thereof. The GC-FID method is adopted. The gas chromatography detection conditions are as follows: chromatographic column: capillary gas chromatography column, heating program: initial temperature of 80° C., maintained for 5 minutes, The temperature was raised to 250°C at a rate of 6°C/min and kept for 5min; detector: hydrogen flame ionization detector, the temperature of the detector was 300°C; the inlet temperature was 250°C; the carrier gas was nitrogen, helium or argon Gas, the carrier gas flow rate is 28mL/min; the gas chromatograph is also equipped with a split device. The method adopts the area normalization method detected by the FID detector on the capillary chromatographic column for analysis, and the detection process is fast and simple, and has good precision, reproducibility and stability, and it is the best product of 2-propyl heptanol. Quality control provides an effective way.

Description

A kind of analytical method of 2-propyl heptanol and impurities thereof

technical field

The invention belongs to the technical field of analysis and detection, in particular to a method for analyzing 2-propylheptanol and impurities thereof.

Background technique

2-Propylheptanol (2-PH), is a C ₁₀ plasticizer raw material alcohol. The raw material for producing 2-PH can come from the raffinate C ₄ olefins of the cracking unit or the mixed C ₄ olefins by-produced from the methanol-to-olefins (MTO) unit. BASF Yangzi built a 2-PH unit with an annual production capacity of 80,000 tons in 2012. It uses raffinate oil (mainly butene contained in it), carbon monoxide and hydrogen as raw materials, and is produced by oxo synthesis, condensation and hydrogenation. 2-PH.

At present, BASF Germany and BASF Yangzi both use GC method (enterprise standard Q/3201 BYC50-2018) to analyze 2-PH and its impurity content to ensure the quality of 2-PH products. In 2018, during the overhaul of the 2-PH unit of BASF Yangzi's OX unit (alcohol product unit), the 2-PH product detected by this method was unqualified for a long time, mainly characterized by an impurity component "hexenal" The content exceeds the standard (see Figure 1): the hexenal content is about 0.5% (internal control standard < 0.15%), resulting in unqualified 2-PH products. Through the analysis of the 2-PH production process, the process experts believe that the excessive "hexenal" is actually the decomposition product diol of the catalyst in the condensation reaction, not the product impurity 5-methyl-2-propyl hexane in the control standard Alkenal. In order to verify the analysis results, BASF Yangzi sent the 2-PH sample to a third-party testing agency for component analysis. The carbonyl value test showed that the sample did not contain aldehyde groups; mass spectrometry analysis showed that the sample did not contain hexenal, but contained a dioxenal. alcohol. BASF Yangzi added the diol standard substance to the 2-PH product, and the chromatographic peak of the standard substance was completely overlapped with the chromatographic peak of the suspected impurity component, a kind of "hexenal", using the existing 2-PH analysis method (see Accompanying drawing 2), further confirms that the "hexenal" exceeding the standard detected by the existing method is actually the catalyst decomposition product diol, not the product impurity 5-methyl-2-propyl hexenal in the control standard.

It can be seen from the above conclusions that the current analytical methods for 2-PH and its impurity content cannot accurately control the quality of 2-PH products during start-up. Using the existing 2-PH analysis method, the impurity 5-methyl-2-propyl hexenal in the control standard cannot be separated from the decomposition product diol in the catalyst solution, thus causing 5- The detection result of methyl-2-propylhexenal was high. At the same time, BASF currently has no method for the determination of the decomposition products in the catalyst solution during the start-up of the 2-PH unit. Therefore, creating an analytical method that can accurately measure 2-PH and its impurity content during start-up can make up for the shortcomings of BASF's 2-PH measurement method, and it is particularly important to ensure the quality of 2-PH products during start-up. have important economic value.

SUMMARY OF THE INVENTION

Purpose of the invention: the purpose of the invention is to aim at the deficiencies in the prior art, provide a kind of diol and impurity hexenal that can correctly separate the 2-PH product, thereby accurately measure the analysis of 2-propyl heptanol and its impurities during driving method.

The analytical method provided by the invention is suitable for 2-propylheptanol produced by oxo synthesis, condensation, hydrogenation and rectification using raffinate oil (mainly butene contained therein), carbon monoxide and hydrogen as raw materials.

Technical scheme: the purpose of the present invention is realized through the following technical scheme:

The invention provides a method for analyzing 2-propylheptanol and impurities thereof. The content of 2-propylheptanol and impurities thereof is determined by a GC-FID method. The gas chromatography detection conditions are as follows:

Chromatographic column: capillary gas chromatographic column, heating program: initial temperature 80°C, hold for 5min, increase to 250°C at a rate of 6°C/min, hold for 5min;

Detector: hydrogen flame ionization detector, the temperature of the detector is 300°C; the temperature of the injection port is 250°C;

The carrier gas is nitrogen, helium or argon, and the carrier gas flow rate is 28mL/min;

The gas chromatograph is also equipped with a split device.

Preferably, the gas chromatography detection conditions are:

Chromatographic column: 30m×0.25mm×1μm, DB-1 capillary column,

Injection volume: 0.2 μL,

Flow rate: 1.3mL/min,

The carrier gas is nitrogen,

Air flow rate: 400mL/min,

Hydrogen flow rate: 30mL/min,

Split ratio: 80:1.

Preferably, the analytical method of described 2-propyl heptanol and impurity thereof mainly comprises the following steps:

(1) Sample preparation: direct analysis after sampling from the 2-propylheptanol production device;

(2) Working reference solution: Since the 2-propylheptenal product contains 5-methyl-2-propyl hexenal, take the 2-propyl hexenal containing 5-methyl-2-propyl hexenal The base heptenal solution is used as the working reference solution; there is no need to prepare the standard solution of impurity 5-methyl-2-propyl hexenal;

(3) Diol standard solution: use 2-propylheptanol containing no impurity 5-methyl-2-propyl hexenal as a solvent to prepare a diol standard solution with a concentration of 0.3 to 1.5 wt%;

(4) adding the working reference substance solution in step (2) to the diol standard solution in step (3) to obtain a system suitability solution containing 5-methyl-2-propyl hexenal and diol ; The content of 5-methyl-2-propylhexenal in the system suitability solution is 0.02-0.05wt%, and the content of diol is 0.3-1.5wt%.

(5) Determine the content of 2-propylheptanol and its impurities by GC-FID method.

Preferably, the analysis method further includes the following steps: after the instrument is stabilized, the error of two consecutive injections is less than 1%, and the area normalization method is used to analyze the content of 2-propylheptanol and its impurities. The calculation formula is as follows:

In the calculation formula, Ci is the content of each component in the sample, wt%; Ai is the peak area of each component;

_CH2O is water content, wt%.

Beneficial effects:

(1) the analytical method of the present invention can accurately measure 2-PH and its impurity content, make up the defect of BASF company to the 2-PH measuring method; - Methyl-2-propylhexenal assay has no separation problems. Using the original analysis method, the decomposition product in the catalyst solution was misjudged as the impurity 5-methyl-2-propyl hexenal, resulting in a long number of days of unqualified 2-PH products; the analysis method of the present invention helps the company 2- During the shutdown period of the PH alcohol device, the unqualified days of 2-PH products are shortened by 5 to 7 days, resulting in considerable economic benefits. After rough calculation, it can save at least 1.7 million yuan each time it starts. In addition, the analysis method of the present invention can be applied in similar devices, resulting in positive economic benefits.

(2) The detection process of the analytical method of the present invention is fast and simple, and has good precision, reproducibility and stability, and provides an effective way for the quality control of 2-PH.

Description of drawings

Fig. 1 is the GC chromatogram of the 2-propylheptanol product detected by the existing method; wherein, 12.36min is the chromatographic peak of a kind of "hexenal" of suspected impurity component in the 2-PH product.

Fig. 2 is the GC chromatogram of the diol standard substance detected by the existing method added to the 2-PH product; wherein, 12.36min is the chromatographic peak where the standard substance and the suspected impurity component "hexenal" completely overlap.

Fig. 3 is the GC chromatogram of the system suitability solution detected by the analytical method of the present invention;

Among them, 15.423min is the chromatographic peak of 4-methyl-2-propyl hexenal, 15.883min is the chromatographic peak of 5-methyl-2-propyl hexenal, 15.723min is the chromatographic peak of diol, 17.738 min is the chromatographic peak of 2-propylheptanol.

Fig. 4 is the GC chromatogram of the 2-PH product that the analytical method of the embodiment of the present invention detects;

Among them, 15.734min is the chromatographic peak of diol, and 17.753min is the chromatographic peak of 2-propylheptanol.

Detailed ways

The technical solutions of the present invention will be described in detail below through specific embodiments and accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

Instrument: Agilent-6890 gas chromatograph (with FID detector, Agilent, USA)

Sample: 2-PH product comes from BASF Yangzi; working reference 2-propylheptenal product comes from BASF Yangzi; the decomposition product diol in the catalyst solution comes from TCI-Tixiai (Shanghai) Chemical Industry Development Co., Ltd. Company, content >97%, batch number TU5YE-01.

In the 2-PH internal control standard, the internal control standard of impurity 5-methyl-2-propyl hexenal is required to be less than 0.15%, and the product is qualified.

Example 1:

Gas chromatography conditions:

Chromatographic column: 30m×0.25mm×1μm, DB-1 capillary column

The inlet temperature is 250°C, and the detector temperature is 300°C;

The carrier gas is nitrogen, and the carrier gas flow rate is 28mL/min; the air flow rate: 400mL/min, and the hydrogen flow rate: 30mL/min;

Split ratio: 80:1.

Heating program: the initial temperature was 80 °C, maintained for 5 min, and the temperature was increased to 250 °C at a rate of 6 °C/min, maintained for 5 min; injection volume: 0.2 μL; flow rate: 1.3 mL/min.

Analysis time: 38.5min.

testing method:

(1) Sample preparation: directly analyze after collecting 2-PH sample from 2-propylheptanol production device;

(2) Working reference solution: Accurately weigh 0.1719g containing 4-methyl-2-propylhexenal with a known concentration of 3.676wt% and 5-methyl-2-propyl with a concentration of 2.789wt% 2-propylheptenal solution of hexenal, as a working reference solution;

(3) Diol standard solution: use the 2-PH (2-propylheptanol) product of the 2-PH device without impurity 5-methyl-2-propyl hexenal as the solvent, use the purchased diol Standard product, prepared into a standard solution with a concentration of 1.292 wt% (weigh 0.3982 g of standard product and dilute to 29.8972 g).

(4) adding the working reference substance solution in step (2) to the standard solution in step (3) (weighing the total weight is 30.0691g) to obtain a solution containing 5-methyl-2-propyl hexenal and System suitability solutions for glycols;

(5) Determination of content by GC-FID method.

After the instrument is stabilized, the error of two consecutive injections is less than 1%. The area normalization method is used to analyze the content of 2-propylheptanol and its impurities. The calculation formula is as follows:

In the calculation formula, Ci is the content of each component in the sample, wt%; Ai is the peak area of each component;

_CH2O is water content, wt%.

Taking the system suitability solution as a sample, the analysis method of the present invention is used to measure the content of the main components therein, and the detection results are shown in Table 1.

The GC chromatogram of the system suitability solution is shown in Figure 3, in which, 15.423min is the chromatographic peak of 4-methyl-2-propylhexenal, and 15.883min is the chromatogram of 5-methyl-2-propylhexenal Peak, 15.723min is the chromatographic peak of diol, 17.738min is the chromatographic peak of 2-propylheptanol.

Table 1 GC determination values of the main components in the system suitability solution

Determination of content calculation: Determination of content = average value * dilution ratio

For 4-methyl-2-propylhexenal and 5-methyl-2-propylhexenal in system suitability solution, its dilution factor=30.0691/0.1719=174.92; for system suitability solution Diol and 2-propylheptanol, its dilution factor=30.0691/29.8972=1.01.

Through the conversion of the dilution ratio, that is, multiplying the GC measurement value and the dilution ratio, the contents of the main components in the working reference solution and the standard solution before dilution are obtained (that is, the measured contents in Table 2 are obtained). "Actual content" in Table 2 refers to the original concentration of the working reference solution (GC measured value) and the prepared concentration of the standard solution.

The measurement result of the main component of the method of the present invention of table 2 is compared with the data of its actual content

Determination content (%) Actual content (%) Relative error% 4-Methyl-2-propylhexenal 3.673 3.676 -0.09 Diol 1.274 1.292 -0.47 5-Methyl-2-propylhexenal 2.974 2.789 6.63 2-Propylheptanol 92.330 92.803 -5.10

As can be seen from Table 2, the method of the present invention can not only effectively separate each impurity, especially separate 5-methyl-2-propyl hexenal from diol completely, and also can accurately measure each impurity content; from the measurement result, It can fully meet the process requirements, and the determination results and actual content also meet the sample recovery rate determination requirements in the analysis method: 90-110%.

The 2-PH product directly sampled is detected by the analytical method of the present invention, and the content of each component is directly obtained from GC; and the diol and 5-methyl-2-propyl hexenal are separated.

The test results of 2-PH products are shown in Table 3:

Figure 4 is the GC chromatogram of the 2-PH product; wherein, 15.734min is the chromatographic peak of diol, and 17.753min is the chromatographic peak of 2-propylheptanol.

Table 3 Contents of main components in 2-PH products

As can be seen from the detection results, the analysis method of the present invention can not only detect the 2-PH product containing the above-mentioned several impurities, but also can effectively detect the new impurity diol in the 2-PH product, the chromatographic peaks of each impurity are well separated, and the quantification is accurate. It can fully meet the requirements of process data analysis. Judging from the measurement results, the measurement results and the actual content also meet the requirements for the determination of the sample recovery rate in the analysis method: 90-110%.

Repeatability:

The same operator uses the same instrument and under the same operating conditions, with normal and correct operating methods for more than two repeatable measurements on the same sample, and the relative deviation of the measured values is not greater than 2%.

stability:

Different operators use different instruments to measure the same sample, and the relative deviation of the two measurement results is not more than 5%.

Embodiment 2: the standard addition recovery experiment of measuring diol using the analytical method of the present invention

Using the 2-PH (2-propylheptanol) product of the 2-PH device as a solvent, and using the purchased diol standard product, a standard solution with a content of 0.3518% was prepared.

Determination of diols:

The results of the three determinations were 0.338%, 0.336% and 0.338%, respectively, the recovery rate: 95.89%; RSD (relative mean deviation): 0.3% (<2%).

The analytical method of the invention has a fast and simple detection process, and has good precision, reproducibility and stability, and provides an effective way for the quality control of 2-PH.

As mentioned above, although the present invention has been shown and described with reference to specific preferred embodiments, this should not be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (4)

1. the analysis method of a kind of 2- propyl enanthol and its impurity, which is characterized in that measure 2- propyl enanthol using GC-FID method And its content of impurity, gas chromatographic detection condition are as follows:

Chromatographic column: temperature program: capillary gas chromatographic column 80 DEG C of initial temperature, keeps 5min, with the rate liter of 6 DEG C/min Temperature keeps 5min to 250 DEG C；

Detector: flame ionization ditector, 300 DEG C of the temperature of the detector；250 DEG C of injector temperature；

Carrier gas is nitrogen, helium or argon gas, flow rate of carrier gas 28mL/min；

Gas chromatograph is also configured with part flow arrangement.

2. the analysis method of 2- propyl enanthol according to claim 1 and its impurity, which is characterized in that the gas-chromatography Testing conditions are as follows:

Chromatographic column: 30m × 0.25mm × 1 μm, DB-1 capillary chromatographic column,

Sampling volume: 0.2 μ L,

Flow velocity: 1.3mL/min,

Carrier gas is nitrogen,

Air velocity: 400mL/min,

Hydrogen flow rate: 30mL/min,

Split ratio: 80:1.

3. the analysis method of 2- propyl enanthol according to claim 1 or 2 and its impurity, which is characterized in that mainly include Following steps:

(1) it sample preparation: is directly analyzed after being sampled in 2- propyl enanthol process units；

(2) working reference substance solution: take the 2- propyl heptenal for containing 5- methyl-2-propyl hexenoic aldehyde molten as working reference substance Liquid；Without preparing the standard solution of impurity 5- methyl-2-propyl hexenoic aldehyde；

(3) decomposition product glycol standard solution: use the 2- propyl enanthol of 5- methyl-2-propyl hexenoic aldehyde free from foreign meter as molten Agent, being configured to concentration is 0.3~1.5wt% glycol standard solution；

(4) the working reference substance solution in step (2) is added in the glycol standard solution in step (3), is obtained containing 5- The system suitability solution of methyl-2-propyl hexenoic aldehyde and glycol；

(5) with the content of GC-FID method measurement 2- propyl enanthol and its impurity.

4. the analysis method of 2- propyl enanthol according to claim 3 and its impurity, which is characterized in that further include following step Rapid: after instrument stabilizer, two needle error of continuous sample introduction analyzes 2- propyl enanthol using area normalization method and its impurity contains less than 1% Amount, calculation formula are as follows:

In the calculation formula, Ci is the content of each component in sample, wt%；Ai is the peak area of each component；C_H2OContain for water Amount, wt%.