CN111024856A - Method for measuring contents of components of high-boiling-point substance in R142b production process by using phase chromatography - Google Patents
Method for measuring contents of components of high-boiling-point substance in R142b production process by using phase chromatography Download PDFInfo
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Abstract
A method for measuring the content of each component of a high-boiling-point substance in the R142b production process by using a phase chromatography belongs to the technical field of chemical product analysis methods. The method is characterized in that: the stationary phase of the chromatographic column is: DB-5 capillary column; column temperature of the chromatographic column: 50-260 ℃; the sample injection amount is 0.1-10 mu L; carrier gas flow: 0.5-5.0 mL/min; the split ratio is as follows: 5: 1-80: 1; vaporization chamber temperature: 100-250 ℃; detector temperature: 150-320 ℃; the components are selected from one or more than two of the following combinations: r142, R132b, R132a, unknown 1, unknown 2, and unknown 3. The invention provides a novel method for measuring the content of each component of a high-boiling-point substance in the production of 1-chloro-1, 1-difluoroethane by a gas chromatography, which is simple, convenient, rapid, accurate and reliable, and is suitable for popularization in the industry.
Description
Technical Field
The invention belongs to the technical field of chemical product analysis methods, and particularly relates to a method for determining the content of each component of a high-boiling-point substance in the production process of R142b by using a phase chromatography method.
Background
1-chloro-1, 1-difluoroethane (R142 b for short) is an important fluorine-containing compound and is widely applied to the fields of refrigeration, foaming, new material synthesis and the like. In particular, it is widely used as a raw material for synthesizing a polyvinylidene fluoride resin.
The production method of R142b generally adopts 1, 1-difluoroethane (R152 a) as a raw material, and the R142b is generated by the reaction of gas-phase photochlorination technology and chlorine. The method has mature technology and simple process, and is the main production method of R142b at present. However, the main disadvantage of this process is the formation of a certain amount of high-boiling by-products. The amount of the side products accounts for about 5 percent of the yield of the R142b, and the components are complex, and because the boiling points of the side products are higher than that of the main product R142b, the side products are enriched at the bottom of a rectifying tower in the rectification and purification process of the R142b product and are discharged from the bottom of the rectifying tower, and the side products are collectively called high-boiling substances.
The compositions of the high-boiling residues are slightly different due to different light reaction temperatures and different or fluctuating light intensities of different enterprises.
At present, different R142b manufacturers have different treatment methods for the high boiling substances, and some of the high boiling substances are sold as solvents. Some enterprises burn the high-boiling residues, which not only wastes resources, but also increases the production cost of the enterprises.
At present, enterprises adopt a rectification means to carry out rectification separation on high-boiling residues so as to obtain useful substances in the high-boiling residues, and because the high-boiling residues are complex in composition and are mostly isomers, the boiling points are very close, and the high-boiling residues are difficult to separate even a rectification technology is adopted. Therefore, only part of useful products can be recovered by adopting the rectification technology, and all substances in high-boiling residues cannot be fully recovered.
In order to recycle the high-boiling substances generated in the production process of the 1,1, 1-chlorodifluoroethane as much as possible, various components in the high-boiling substances need to be analyzed, and the usable substances need to be recycled in a targeted manner.
Although the HG/T4795 standard refers to the analysis method of R142b, the present invention mainly aims at the analysis method of R142b high boiling substances, and the emphasis is different. Impurities such as R132b and R132a according to the present invention could not be detected in HG/T4795 standard.
Disclosure of Invention
The invention aims to provide a novel method for measuring the content of each component of a high-boiling-point substance in the production of 1-chloro-1, 1-difluoroethane by using a gas chromatography, which is simpler, quicker, more accurate and more reliable.
The technical scheme adopted by the invention for achieving the aim of the invention is as follows: a method for measuring the contents of various components of a high-boiling-point substance in the R142b production process by using a phase chromatography is characterized in that:
the stationary phase of the chromatographic column is: a DB-5 capillary column, wherein the specification of the capillary column is (25-60) mX (200-530) mu mX (0.1-5.0) mu m; column temperature of the chromatographic column: 50-260 ℃; the sample injection amount is 0.1-10 mu L; carrier gas flow: 0.5-5.0 mL/min; the split ratio is as follows: 5: 1-80: 1; vaporization chamber temperature: 100-250 ℃; detector temperature: 150-320 ℃;
the temperature rising mode of the chromatographic column is as follows: the initial temperature is 50-150 ℃, the temperature is kept for 2-5 min, the temperature is raised to 100-240 ℃ at 2-25 ℃, and the temperature is kept for 1-15 min; sample introduction amount: 0.1-10 μ L;
the components are selected from one or more than two of the following combinations: r142, R132b, R132a, unknown 1, unknown 2, and unknown 3.
Preferably, the gas chromatography conditions are:
the chromatographic column is a DB-5 capillary column, and the specification is 30 mX 320 mu mX0.25 mu m;
the temperature rising mode of the column temperature of the chromatographic column is as follows: the initial temperature is 50 ℃, the temperature is kept for 2min, the temperature is raised to 150 ℃ at the speed of 10 ℃/min, and the temperature is kept for 1 min;
the detector is a hydrogen flame ionization detector;
the carrier gas is nitrogen with the volume percentage of 99.999 percent;
the fuel gas is hydrogen with the volume percentage of 99.999 percent, and the flow rate is 30 mL/min;
the combustion-supporting gas is air, and the flow rate is 300 mL/min;
the tail gas blowing is nitrogen with the volume percentage of 99.999 percent, and the flow is 25 mL/min;
the carrier gas flow rate is: 0.8 mL/min;
the sample injection amount is as follows: 0.3 mu L;
the split ratio is as follows: 20: 1;
the vaporizer temperature was: 220 ℃;
the detector temperature was: at 300 ℃.
Preferably, the impurity component further comprises other fluorine-containing alkanes, fluorine-containing alkenes and fluorine-containing alkynes.
Preferably, the content of each impurity component is calculated according to an area normalization method.
Preferably, the method for measuring the content of each component of the high-boiling substances in the R142b production process by using the phase chromatography comprises the following steps:
(1) selection of chromatographic conditions
Using a chromatograph, carrying components in a high-boiling substance generated in the production process of the 1-chloro-1, 1-difluoroethane by a carrier gas to sequentially pass through a DB-5 capillary column and a FID detector, wherein the chromatographic conditions are as follows:
a chromatographic column DB-5 capillary column, wherein the specification of the capillary column is (25-60) mX (20-530) mu mX (0.1-5.0) mu m;
keeping the initial temperature of the chromatographic column at 50-150 ℃ for 2-5 min, and raising the temperature to 100-240 ℃ at 2-25 ℃ for 1-15 min;
detector hydrogen Flame Ionization Detector (FID);
nitrogen with 99.999 percent of volume of carrier gas;
the volume percentage of the fuel gas is 99.999 percent of hydrogen, and the flow rate is about 30 mL/min;
combustion-supporting air with the flow rate of 300 mL/min;
the carrier gas flow is 0.5-5 mL/min;
the sample injection amount is 0.2-5 mu L;
the split ratio is 5: 1-80: 1;
the temperature of the vaporization chamber is 220 ℃;
the temperature of the detector is 300 ℃;
(2) analytical testing
The sample passes through a selected chromatographic column under the carrying of carrier gas, the components are separated in the chromatographic column by different distribution coefficients of a mobile phase (carrier gas) and fixed phases, and the components enter a detector in sequence after being separated; different substances have different properties, the electric quantity signals are converted by using the sensor, and the weak electric quantity signals are subjected to signal amplification processing to obtain required data;
the method for measuring the content of each component in the high-boiling-point substance generated in the production process of the 1-chloro-1, 1-difluoroethane by using the gas chromatography provided by the invention not only can qualitatively analyze each impurity component, but also can quantify the content of each impurity. When used for quantitative analysis, the content of each component of the R142b high-boiling substance can be obtained by an area normalization method, which comprises the following steps:
wherein Xi is the content (concentration) of the component i in the sample to be detected; ai- -peak area of component i;
ai- -sum of peak areas of the components.
The invention has the beneficial technical effects that:
in the research and production of 1-chloro-1, 1-difluoroethane (R142 b for short), high-boiling-point substances are used as main impurities, the content of components in the high-boiling-point substances is an important factor influencing the quality of products, and various impurities with similar properties can exist according to different production processes and are difficult to separate. However, the analysis method of each component of the high-boiling-point substance in the production of the 1-chloro-1, 1-difluoroethane is not reported at home at present, so that the establishment of the simple, accurate, rapid and reliable analysis method of each component of the high-boiling-point substance has important significance for the deep processing of the high-boiling-point substance.
The gas chromatography measuring method provided by the invention can measure each component in a high-boiling-point substance generated in the production process of 1,1, 1-chlorodifluoroethane, wherein the component is selected from one or more than two of the following combinations: r142, R132b, R132a, unknown 1, unknown 2, unknown 3. The gas chromatography determination method provided by the invention can further determine other fluorine-containing alkanes, fluorine-containing alkenes and fluorine-containing alkynes.
The measuring and calculating method provided by the invention is reasonable in design, accurate in measurement, scientific and reliable, and suitable for popularization in the industry.
Drawings
FIG. 1 is a chromatogram as described in example 1;
FIG. 2 is a chromatogram as described in example 2.
Detailed Description
The present invention is further illustrated by the following examples, which are not intended to limit the invention.
Example 1:
A7820A gas chromatograph and FID detector from Agilent were used.
The product R142b and the components of the high-boiling components that may be contained in the product are first prepared into test samples, wherein the components contained in the test samples are as follows: r142b, R142, R132b, R132a, unknown 1, unknown 2, and unknown 3.
(1) The chromatographic conditions were chosen as follows:
| serial number | Parameter(s) | |
| 1 | Chromatographic column | DB-5 (30 mX 320. mu. mX0.25 μm) |
| 2 | Column temperature of chromatographic column | Maintaining the initial temperature at 50 deg.C for 2min, heating to 150 deg.C at 10 deg.C/min, and maintaining for 1min |
| 3 | Detector | Hydrogen flame ionChemical detector (FID) |
| 4 | Carrier gas | 99.999% by volume of nitrogen |
| 5 | Gas combustion | 99.999 percent hydrogen by volume and 30mL/min of |
| 6 | Combustion-supporting gas | Air flow rate of 300mL/ |
| 7 | Flow of carrier gas | 0.8mL/ |
| 8 | Sample volume | 0.3μL |
| 9 | Split ratio | 20:1 |
| 10 | Temperature of vaporization chamber | 220℃ |
| 11 | Detector | 300℃ |
The prepared test sample passes through a selected chromatographic column under the carrying of carrier gas, the distribution coefficients of the mobile phase (carrier gas) and the fixed phases of each component in the chromatographic column are different for separation, and the components enter a detector in sequence after separation; different materials have different characteristics, the sensor is converted into an electric quantity signal, and the weak electric quantity signal is processed by a circuit method to obtain required data.
The chromatogram is shown in figure 1. The content of each substance was calculated using an area normalization method, and the results were as follows:
| serial number | Components | Retention time (min) | Content (%) |
| 1 | R142b | 5.07 | 6.38 |
| 2 | R142 | 6.14 | 37.59 |
| 3 | R132b | 6.66 | 4.19 |
| 4 | R132a | 7.12 | 41.57 |
| 5 | Unknown 1 | 8.15 | 4.91 |
| 6 | Unknown 2 | 8.29 | 4.95 |
| 7 | Unknown 3 | 9.08 | 0.38 |
Example 2:
A7820A gas chromatograph and FID detector from Agilent were used.
The same sample as in example 1 was used. At 24 hours intervals after the completion of the example, the same chromatographic conditions as in example 1 were selected for analysis, and the chromatogram is shown in detail in FIG. 2. The content of each impurity was calculated using an area normalization method, and the results were as follows:
| serial number | Components | Retention time (min) | Content (%) |
| 1 | R142b | 5.08 | 6.36 |
| 2 | R142 | 6.15 | 37.61 |
| 3 | R132b | 6.66 | 4.19 |
| 4 | R132a | 7.13 | 41.57 |
| 5 | Unknown 1 | 8.15 | 4.91 |
| 6 | Unknown 2 | 8.29 | 4.95 |
| 7 | Unknown 3 | 9.08 | 0.38 |
It should be noted that the above-mentioned preferred embodiments are merely illustrative of the technical concepts and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (5)
1. A method for measuring the contents of various components of a high-boiling-point substance in the R142b production process by using a phase chromatography is characterized in that:
the stationary phase of the chromatographic column is: a DB-5 capillary column, wherein the specification of the capillary column is (25-60) mX (200-530) mu mX (0.1-5.0) mu m; column temperature of the chromatographic column: 50-260 ℃; the sample injection amount is 0.1-10 mu L; carrier gas flow: 0.5-5.0 mL/min; the split ratio is as follows: 5: 1-80: 1; vaporization chamber temperature: 100-250 ℃; detector temperature: 150-320 ℃;
the temperature rising mode of the chromatographic column is as follows: the initial temperature is 50-150 ℃, the temperature is kept for 2-5 min, the temperature is raised to 100-240 ℃ at 2-25 ℃, and the temperature is kept for 1-15 min; sample introduction amount: 0.1-10 μ L;
the components are selected from one or more than two of the following combinations: r142, R132b, R132a, unknown 1, unknown 2, and unknown 3.
2. The method for determining the contents of the components of high boiling substances in the production process of R142b by using the phase chromatography as claimed in claim 1, wherein:
the gas chromatography conditions were:
the chromatographic column is a DB-5 capillary column, and the specification is 30 mX 320 mu mX0.25 mu m;
the temperature rising mode of the column temperature of the chromatographic column is as follows: the initial temperature is 50 ℃, the temperature is kept for 2min, the temperature is raised to 150 ℃ at the speed of 10 ℃/min, and the temperature is kept for 1 min;
the detector is a hydrogen flame ionization detector;
the carrier gas is nitrogen with the volume percentage of 99.999 percent;
the fuel gas is hydrogen with the volume percentage of 99.999 percent, and the flow rate is 30 mL/min;
the combustion-supporting gas is air, and the flow rate is 300 mL/min;
the tail gas blowing is nitrogen with the volume percentage of 99.999 percent, and the flow is 25 mL/min;
the carrier gas flow rate is: 0.8 mL/min;
the sample injection amount is as follows: 0.3 mu L;
the split ratio is as follows: 20: 1;
the vaporizer temperature was: 220 ℃;
the detector temperature was: at 300 ℃.
3. The method for determining the contents of the components of high boiling substances in the production process of R142b by using the phase chromatography as claimed in claim 2, wherein: the impurity component also comprises other fluorine-containing alkanes, fluorine-containing alkenes and fluorine-containing alkynes.
4. The method for determining the contents of the components of high boiling substances in the production process of R142b by using the phase chromatography as claimed in claim 3, wherein: and the content of each impurity component is calculated according to an area normalization method.
5. The method for determining the contents of the components of high boiling substances in the production process of R142b by using the phase chromatography as claimed in claim 4, wherein: the method comprises the following steps:
(1) selection of chromatographic conditions
Using a chromatograph, carrying components in a high-boiling substance generated in the production process of the 1-chloro-1, 1-difluoroethane by a carrier gas to sequentially pass through a DB-5 capillary column and a FID detector, wherein the chromatographic conditions are as follows:
a chromatographic column DB-5 capillary column, wherein the specification of the capillary column is (25-60) mX (20-530) mu mX (0.1-5.0) mu m;
keeping the initial temperature of the chromatographic column at 50-150 ℃ for 2-5 min, and raising the temperature to 100-240 ℃ at 2-25 ℃ for 1-15 min;
detector hydrogen flame ionization detector;
nitrogen with 99.999 percent of volume of carrier gas;
the volume percentage of the fuel gas is 99.999 percent of hydrogen, and the flow rate is about 30 mL/min;
combustion-supporting air with the flow rate of 300 mL/min;
the carrier gas flow is 0.5-5 mL/min;
the sample injection amount is 0.2-5 mu L;
the split ratio is 5: 1-80: 1;
the temperature of the vaporization chamber is 220 ℃;
the temperature of the detector is 300 ℃;
(2) analytical testing
The sample passes through a selected chromatographic column under the carrying of carrier gas, the mobile phase and the fixed phase of each component in the chromatographic column have different distribution coefficients for separation, and the components enter a detector in sequence after being separated; different substances have different properties, the electric quantity signals are converted by using the sensor, and the weak electric quantity signals are subjected to signal amplification processing to obtain required data;
when used for quantitative analysis, the content of each component of the R142b high-boiling substance can be obtained by an area normalization method, which comprises the following steps:
wherein Xi is the content (concentration) of the component i in the sample to be detected; ai- -peak area of component i;
ai- -sum of peak areas of the components.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101535790A (en) * | 2006-08-01 | 2009-09-16 | 布鲁克斯·兰德实验室有限责任公司 | Automated system for detection of chemical compounds |
| JP2009222477A (en) * | 2008-03-14 | 2009-10-01 | Nippon Polyurethane Ind Co Ltd | Measuring method of residual fluocarbon gas in foam |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101535790A (en) * | 2006-08-01 | 2009-09-16 | 布鲁克斯·兰德实验室有限责任公司 | Automated system for detection of chemical compounds |
| JP2009222477A (en) * | 2008-03-14 | 2009-10-01 | Nippon Polyurethane Ind Co Ltd | Measuring method of residual fluocarbon gas in foam |
Non-Patent Citations (3)
| Title |
|---|
| O"DOHERTY S J 等: "Analysis of replacement chlorofluorocarbons using Carboxen microtraps for isolation and preconcentration in gas chromatography-mass spectrometry", 《JOURNAL OF CHROMATOGRAPHY A》, 31 December 1993 (1993-12-31), pages 123 - 129, XP026554727, DOI: 10.1016/0021-9673(93)83043-R * |
| POORE M W 等: "Determination of exempt and prohibited compounds in consumer products by headspace gas chromatography mass spectrometry", 《JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION》, vol. 46, no. 11, 9 January 2012 (2012-01-09), pages 1093 - 1095 * |
| 唐宏兵 等: "有关工作场所空气中1,1-二氯-2,2,2-三氟乙烷测定方法的研制", 《江苏预防医学》, vol. 17, no. 03, 30 September 2006 (2006-09-30), pages 73 - 75 * |
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