Potentiometric titration is used to determine the flame retardant of bromine

Potentiometric titration is used to determine the flame retardant of bromine

Oxygen flask combustion - potentiometric titration method for determination of bromine content in bromine flame retardants is a rapid, accurate and sensitive chemical analysis method, as long as the sample with correct method, titration process to reduce various factors influencing the accuracy of the measurement results, the precision and accuracy of the measurement result is greatly superior to the traditional volumetric analysis.

With the development of the potentiometric titration analysis instrument technology, the method of potentiometric titration in the determination of bromine flame retardants bromine content is higher and higher degree of automation, towards rapid, sensitive and accurate measuring process; With the improvement of instrument sensitivity, the measurement error of instrument itself is less and less influence on the measurement result.

Thus ensuring potential titration in the determination of bromine flame retardants bromine content is an important factor of the measurement accuracy are increasingly reflected in the process of sample pretreatment, according to different measuring samples with accurate and reliable method of sample pretreatment, become the important work of the measuring results are accurate and reliable.

Brominated flame retardant bromide is completely decomposed, and the absorption liquid is determined by the potentiometric titration method. It is proved that the pH value of the absorbed solution can also affect the accuracy of the measurement results.

When the pH is greater than 1.15, the measurement results of the measured components tend to be low. When the pH is less than 0.95, the results of the measured components are high. Therefore, in order to ensure the accurate and reliable measurement results, the absorption pH value should be strictly controlled between 0.98 and 1.10. 2 potentiometric titration parameter automatic potentiometric titration to determine the influence of bromine content and adding silver nitrate standard titration solution way appropriate chooses DET dynamic as bit patterns, such as the silver nitrate standard titration solution to add the amount for the variable. This model titration curve is flat and the liquid is larger, and the small amount of liquid is used near the end point.



Trimethyl phosphate (TMP)

Synthesis process of Trimethyl phosphate TMP three phosphorus oxychloride with methanol in the presence of potassium carbonate reaction of Trimethyl phosphate. At the same time, the reaction of two with methyl phosphoric acid potassium salt, sulfuric acid two methyl ester reaction of Trimethyl phosphate. Trimethyl phosphate crude product after washing, bleaching, dehydration, vacuum distillation was finished. The consumption of raw material: three phosphorus oxychloride 1094kg/t, methanol 686kg/t.

The methanol and potassium carbonate is added into a reaction kettle, cool to 5 ℃, start dropping three phosphorus oxychloride, temperature control in 30 ℃, 2h dropping after, and then stir 0.5h, pH value control in 7 ~ 8; then add two sulfuric acid methyl ester, reflux for 3h after recovery of methanol, and then the material cooling to 20 DEG C, adding carbon tetrachloride filter, filter cake with a small amount of carbon tetrachloride wash, lotion and the filtrate recycling, carbon tetrachloride, vacuum distillation of crude. The crude product with distilled water and activated charcoal, filtered and anhydrous potassium carbonate dehydration, vacuum distillation to obtain the final product.

Trimethyl phosphate (TMP) use is mainly used in medicine, pesticides, solvents and extractants, used as a solvent, extraction, determination of zirconium and GC stationary liquid, the ester is used in medicine and pesticide solvent and extractant. Pesticide intermediates. In Japan, Trimethyl phosphate use as anti stain of textile oil and polymer, flame retardant additive for lithium ion battery.

Trimethyl phosphate is currently the main market in India, mostly for textile auxiliaries, the products are mainly exported to Japan, South Korea, Thailand, India.

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The advantages of this method are fast and reliable. If titration, etc when near the point of minimum volume addition amount is too small, the smaller the volume increase, lead to the titration curve response information, the more some redundant end, will lead to excessive titration accuracy is poorer, the need to increase the amount of silver nitrate standard titrate solution of minimum; Minimum standard titration solution if the silver nitrate addition amount is too large, will cause when points, such as curve is too steep or over the need to reduce the amount of silver nitrate standard titrate solution of minimum, make its not exceed 1% of the burette volume; If the titration time is longer, the minimum amount of added weight or the density value of the measuring point should be increased.

The minimum amount of liquid in the standard titration solution for the determination of bromide ion is 10.0 mu L and the measuring point density is 4. Potentiometric titration parameter changes in the most directly reflected in the change of the titration curve, therefore must according to the changed conditions on the silver nitrate standard titration solution for the amount of the minimum adjustment, to ensure the accuracy of measurement results.

The sealing of the hydraulic unit and the burette unit is clean and clean. Full titration should not adhere to or produce bubbles, and bubbles are another important factor affecting the accuracy of measurement results. If air bubbles appear in the process of adding liquid, check whether the pipeline is tightened and the piston and buret in the switching unit wear out and whether there is dirt. If any of the above conditions occur, the cleaning should be removed, or the pipe can be played or pressed, and the liquid shall be emptied to ensure no air bubbles in the adding process.

Stirring speed. The titration of titration is mixed with the liquid to be tested, and the mixing speed should be set to produce a small "stirring vortex". If the mixing speed is too fast, it will absorb the air bubble and lead to the wrong measurement. If the mixing speed is too low, the titration can not be sufficiently mixed with the liquid to be tested, and the reaction is not complete, causing the electrode potential change to not accurately reflect the titration result; In addition, the tip of the titrator should be kept in the "stirring vortex". Add the titration liquid to the electrical level as far as possible.

Check whether the titration nozzle is added to prevent diffusion titration. In the automatic potentiometric titration device, titrant of the liquid in the burette and drainage process is done automatically, and automatic titrator at boot time there will be an automatic balancing process, at this time if not immersed in the test solution, titration nozzle there would be no diffusion phenomenon, but will produce bubbles; If the titration nozzle is immersed in the measured solution of the titration pool, it is easier to absorb the measured fluid.

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