News Details
Determination of bromination flame retardants for polyurethane by potentiometric titration
2017-12-2 11:56:53
Determination of bromination flame retardants for polyurethane by potentiometric titration
- the potentiometric titration method for determination of polyurethane by oxygen flask combustion bromine content of brominated flame retardants is a rapid, accurate and sensitive method for chemical analysis of samples, as long as the correct treatment, the titration process to minimize various factors affecting the accuracy of the measurement results, the measurement results of the analysis precision and accuracy is much better than the traditional capacity.
With the development of instrument technology of potentiometric titration analysis, determination of bromine content of brominated flame retardants in the increasingly high degree of automation of polyurethane potentiometric titration, the measurement process toward the development of rapid, sensitive and accurate direction; with the instrument to improve the sensitivity of the instrument itself, the influence of measurement errors on the measurement results is also more and more small.
More and more important factor therefore protect the potentiometric titration method for the determination of polyurethane measuring results for bromine content of brominated flame retardants in accuracy in sample pretreatment process, the samples were measured using different accurate and reliable sample pretreatment methods, has become an important task to ensure accurate and reliable measurement results.
Bromine ion is completely decomposed and absorbed in brominated flame retardant, and the absorption solution is determined by potentiometric titration with silver nitrate standard titration solution. The test results show that the pH value of the absorption solution will also affect the accuracy of the measurement results.
When pH = 1.15, are often caused by the analyte measurement results is low; when the pH is less than or equal to 0.95, are often caused by the analyte measurement result is high. Therefore, in order to ensure the accuracy and reliability of the measurement results, the pH value of the absorption solution should be strictly controlled between 0.98 and 1.10. 2, the influence of potentiometric titration parameters. When the bromine content is determined by automatic potentiometric titre, the DET dynamic equivalent point titration mode should be selected when adding the silver nitrate standard titration solution. The dosage of silver nitrate standard titration solution is variable. The amount of liquid in the flat part of the titration curve is larger, and the small amount of liquid is used near the end point.
The advantages of the addition method are fast and reliable. If the minimum volume titration near the amount is too small, the volume increased by smaller, more information in the titration curve of reaction, some excess will lead to excessive titration end point, poor accuracy, minimum amount of time required to increase the standard titration solution of silver nitrate; if the minimum standard titration solution of silver nitrate the amount is too large, will cause the curve is too steep or over the minimum amount, the need to reduce the standard titration solution of silver nitrate, so that it does not exceed 1% of the volume of the buret; if the titration time is longer, should increase the minimum adding amount or reduce the measuring point density value.
The minimum liquid content of silver nitrate standard titration solution is 10 mu L, and the measured point density is 4. The change of potential titration parameter is most directly reflected in the change of titration curve. Therefore, it is necessary to adjust the minimum amount of standard titration solution of silver nitrate according to the changing conditions, so as to ensure the accuracy and reliability of the measurement results.
The liquid pipeline unit unit and burette sealing better and clean.
Tris(2-chloroisopropyl)Phosphate(TCPP)
Packing: NW 250KG / galvanized iron (a small cabinet to play prop 20 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons), or 23 tons ISOTANK.
The product output: 100 tons / month
Shipping Port: China Shang Hai
Price offer is valid: 15 days
Jincang time: 15 days (commodity inspection)
Export rights: the right to import and export company.
The product is used for the soft / hard polyurethane foam, with thermal and hydrolytic stability good, especially suitable for ASTME84 (Level 11) foam, with low viscosity unsaturated polyester resin in low temperature application and phenolic plastics at. This product is also used to grab the foam sealant and sheet production. For polyvinyl chloride, polystyrene, phenolic resin, acrylic resin and rubber, coating, flame retardant, also used for soft and hard polyurethane foam, epoxy resin, polystyrene, cellulose acetate, ethyl cellulose tree and phenolic plastics, polyvinyl acetate and gun type foam sealant production. Particularly recommended for rigid polyurethane foam has excellent thermal and hydrolytic stability is particularly suitable for ASTM84 (II), compound for polyurethane foam and unsaturated resin and phenolic plastics.
The full filled titrant should not attach or produce bubbles. Bubbles are another important factor affecting the accuracy of the measurement results. If the bubble has emerged in the process of filling liquid, check whether the pipeline should be tightened, exchange unit and piston burette is worn, whether there is dirt. In the case of the above conditions, the cleaning should be unloaded, or the pipe can be played or press the emptying key to emptying the liquid, so as to ensure that there is no bubble in the process of adding liquid.
Stirring speed. Titration of titrant and the liquid to be mixed reaction, stirring speed should be set up to produce a small whirlpool to stir "". If the stirring speed is too fast, it will cause the error of the adsorption bubble measurements; if the stirring speed is too low will cause the titrant solution and insufficient mixing, the reaction is not complete, resulting in changes in electrode potential can not accurately reflect the results of titration determination; also, also should be as much as possible in the "mixing head burette vortex is larger; between the liquid level to add titration electric distance as far as possible.
Check whether the titrating nozzle is added to the diffusion titrated head. In the automatic potentiometric titration apparatus, liquid filling agent and the titration burette discharge process is completed automatically, and the automatic titrator at startup will have an automatic balancing process, if the nozzle is not immersed in the titration solution was measured, no diffusion phenomena, but will produce bubbles; if the solution is titration the nozzle immersion titration pool, it is easy to absorb by liquid.
Because the titration solution and measured liquid will be generated between the diffusion diffusion phenomenon, will affect the results of titration. The diffusion affected by the titration solution and measured liquid concentration difference, the difference is more prone to spread the phenomenon of concentration, the determination results is not accurate. If the diffusion titrated head is added, the capillary part of the front end of the titrating nozzle is present when the liquid is produced by the diffusion, which inhibits the diffusion between the two. If the anti diffusion titre head is lost, the titrant will flow into the titration pool and react with the sample, but the consumption of this part is not calculated, which will lead to large measurement deviation.
The accuracy of the burette accuracy will also directly affect the determination result, small volume in the titration consumption standard titration solution of silver nitrate, generally less than 2mL, so we should choose 5mL or 10mL microburet.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
- the potentiometric titration method for determination of polyurethane by oxygen flask combustion bromine content of brominated flame retardants is a rapid, accurate and sensitive method for chemical analysis of samples, as long as the correct treatment, the titration process to minimize various factors affecting the accuracy of the measurement results, the measurement results of the analysis precision and accuracy is much better than the traditional capacity.
With the development of instrument technology of potentiometric titration analysis, determination of bromine content of brominated flame retardants in the increasingly high degree of automation of polyurethane potentiometric titration, the measurement process toward the development of rapid, sensitive and accurate direction; with the instrument to improve the sensitivity of the instrument itself, the influence of measurement errors on the measurement results is also more and more small.
More and more important factor therefore protect the potentiometric titration method for the determination of polyurethane measuring results for bromine content of brominated flame retardants in accuracy in sample pretreatment process, the samples were measured using different accurate and reliable sample pretreatment methods, has become an important task to ensure accurate and reliable measurement results.
Bromine ion is completely decomposed and absorbed in brominated flame retardant, and the absorption solution is determined by potentiometric titration with silver nitrate standard titration solution. The test results show that the pH value of the absorption solution will also affect the accuracy of the measurement results.
When pH = 1.15, are often caused by the analyte measurement results is low; when the pH is less than or equal to 0.95, are often caused by the analyte measurement result is high. Therefore, in order to ensure the accuracy and reliability of the measurement results, the pH value of the absorption solution should be strictly controlled between 0.98 and 1.10. 2, the influence of potentiometric titration parameters. When the bromine content is determined by automatic potentiometric titre, the DET dynamic equivalent point titration mode should be selected when adding the silver nitrate standard titration solution. The dosage of silver nitrate standard titration solution is variable. The amount of liquid in the flat part of the titration curve is larger, and the small amount of liquid is used near the end point.
The advantages of the addition method are fast and reliable. If the minimum volume titration near the amount is too small, the volume increased by smaller, more information in the titration curve of reaction, some excess will lead to excessive titration end point, poor accuracy, minimum amount of time required to increase the standard titration solution of silver nitrate; if the minimum standard titration solution of silver nitrate the amount is too large, will cause the curve is too steep or over the minimum amount, the need to reduce the standard titration solution of silver nitrate, so that it does not exceed 1% of the volume of the buret; if the titration time is longer, should increase the minimum adding amount or reduce the measuring point density value.
The minimum liquid content of silver nitrate standard titration solution is 10 mu L, and the measured point density is 4. The change of potential titration parameter is most directly reflected in the change of titration curve. Therefore, it is necessary to adjust the minimum amount of standard titration solution of silver nitrate according to the changing conditions, so as to ensure the accuracy and reliability of the measurement results.
The liquid pipeline unit unit and burette sealing better and clean.
Tris(2-chloroisopropyl)Phosphate(TCPP)
Packing: NW 250KG / galvanized iron (a small cabinet to play prop 20 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons), or 23 tons ISOTANK.
The product output: 100 tons / month
Shipping Port: China Shang Hai
Price offer is valid: 15 days
Jincang time: 15 days (commodity inspection)
Export rights: the right to import and export company.
The product is used for the soft / hard polyurethane foam, with thermal and hydrolytic stability good, especially suitable for ASTME84 (Level 11) foam, with low viscosity unsaturated polyester resin in low temperature application and phenolic plastics at. This product is also used to grab the foam sealant and sheet production. For polyvinyl chloride, polystyrene, phenolic resin, acrylic resin and rubber, coating, flame retardant, also used for soft and hard polyurethane foam, epoxy resin, polystyrene, cellulose acetate, ethyl cellulose tree and phenolic plastics, polyvinyl acetate and gun type foam sealant production. Particularly recommended for rigid polyurethane foam has excellent thermal and hydrolytic stability is particularly suitable for ASTM84 (II), compound for polyurethane foam and unsaturated resin and phenolic plastics.
The full filled titrant should not attach or produce bubbles. Bubbles are another important factor affecting the accuracy of the measurement results. If the bubble has emerged in the process of filling liquid, check whether the pipeline should be tightened, exchange unit and piston burette is worn, whether there is dirt. In the case of the above conditions, the cleaning should be unloaded, or the pipe can be played or press the emptying key to emptying the liquid, so as to ensure that there is no bubble in the process of adding liquid.
Stirring speed. Titration of titrant and the liquid to be mixed reaction, stirring speed should be set up to produce a small whirlpool to stir "". If the stirring speed is too fast, it will cause the error of the adsorption bubble measurements; if the stirring speed is too low will cause the titrant solution and insufficient mixing, the reaction is not complete, resulting in changes in electrode potential can not accurately reflect the results of titration determination; also, also should be as much as possible in the "mixing head burette vortex is larger; between the liquid level to add titration electric distance as far as possible.
Check whether the titrating nozzle is added to the diffusion titrated head. In the automatic potentiometric titration apparatus, liquid filling agent and the titration burette discharge process is completed automatically, and the automatic titrator at startup will have an automatic balancing process, if the nozzle is not immersed in the titration solution was measured, no diffusion phenomena, but will produce bubbles; if the solution is titration the nozzle immersion titration pool, it is easy to absorb by liquid.
Because the titration solution and measured liquid will be generated between the diffusion diffusion phenomenon, will affect the results of titration. The diffusion affected by the titration solution and measured liquid concentration difference, the difference is more prone to spread the phenomenon of concentration, the determination results is not accurate. If the diffusion titrated head is added, the capillary part of the front end of the titrating nozzle is present when the liquid is produced by the diffusion, which inhibits the diffusion between the two. If the anti diffusion titre head is lost, the titrant will flow into the titration pool and react with the sample, but the consumption of this part is not calculated, which will lead to large measurement deviation.
The accuracy of the burette accuracy will also directly affect the determination result, small volume in the titration consumption standard titration solution of silver nitrate, generally less than 2mL, so we should choose 5mL or 10mL microburet.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
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