This is a bilingual snapshot page saved by the user at 2025-7-2 18:16 for https://app.immersivetranslate.com/pdf-pro/409a70a1-8f09-4719-8cb8-aec85ff5411f/, provided with bilingual support by Immersive Translate. Learn how to save?
  The name of the file   Document number KHZY / 17 − 086 KHZY / 17 − 086 KHZY//17-086\mathrm{KHZY} / 17-086
  Version number D / 1 D / 1 D//1\mathrm{D} / 1
  Method for determination of tetrahydrofuran peroxide content   Page 46 / 60 46 / 60 46//6046 / 60
  Controlled state
文件名称 文件编号 KHZY//17-086 版本号 D//1 四氢呋喃过氧化物含量测定方法 页次 46//60 受控状态 | 文件名称 | 文件编号 | $\mathrm{KHZY} / 17-086$ | | :---: | :---: | :--- | | | 版本号 | $\mathrm{D} / 1$ | | 四氢呋喃过氧化物含量测定方法 | 页次 | $46 / 60$ | | | 受控状态 | |

  1. Principle:

The peroxide in tetrahydrofuran (THF) reacts with potassium iodide under acidic conditions, and the reaction is titrated with sodium thiosulfate to generate free iodine, which can quantitatively calculate the peroxide content. The reaction equation is as follows:
H 2 O 2 + 2 I + 2 H → I 2 + 2 H 2 O 2 S 2 O 3 2 − + I 2 → SO 61 + 2 I − H 2 O 2 + 2 I + 2 H → I 2 + 2 H 2 O 2 S 2 O 3 2 − + I 2 → SO 61 + 2 I − {:[H_(2)O_(2)+2I+2HrarrI_(2)+2H_(2)O],[2S_(2)O_(3)^(2-)+I_(2)rarrSO_(61)+2I^(-)]:}\begin{aligned} & \mathrm{H}_{2} \mathrm{O}_{2}+2 \mathrm{I}+2 \mathrm{H} \rightarrow \mathrm{I}_{2}+2 \mathrm{H}_{2} \mathrm{O} \\ & 2 \mathrm{~S}_{2} \mathrm{O}_{3}^{2-}+\mathrm{I}_{2} \rightarrow \mathrm{SO}_{61}+2 \mathrm{I}^{-} \end{aligned}

  2. Reagents:

  Potassium iodide analysis pure

  Acetic acid is analytically pure
  Sodium 0.1 moL / L 0.1 moL / L 0.1moL//L0.1 \mathrm{moL} / \mathrm{L} thiosulfate

  2. Instrument:

  Electromagnetic stirrer
  Erlenmeyer flask 300 mL 300 mL quad300mL\quad 300 \mathrm{~mL} with stopper

  Graduated cylinders 500 mL 、 50 mL 500 mL 、 50 mL quad500mL、50mL\quad 500 \mathrm{~mL} 、 50 \mathrm{~mL}、

  Volumetric 1000 mL 、 100 mL 1000 mL 、 100 mL 1000mL、100mL1000 \mathrm{~mL} 、 100 \mathrm{~mL}、 flasks
   Pipettes 20mL, 25mL
   The magnetic stir bar is 20 mm long
  Burette 5 mL 5 mL quad5mL\quad 5 \mathrm{~mL}
   Analytical balance accuracy 0.1 mg

  4. Solution preparation:

   4.110 % 4.110 % 4.110%4.110 \% Preparation of potassium iodide solution

Put 100 g of potassium iodide into a 500 mL beaker, add purified water to dissolve potassium iodide, dissolve and pour 1 L volumetric flask, add purified water to the scale, and shake well. Place the solution in a 1 L brown reagent bottle.
4.220 % 4.220 % 4.220%4.220 \% The acetic acid solution is prepared by adding 400 mL of pure water and 100 mL of acetic acid to a 500 mL graduated cylinder and storing the solution in a 1 L plastic bottle.
  The name of the file   Document number KHZY / 17 − 086 KHZY / 17 − 086 KHZY//17-086\mathrm{KHZY} / 17-086
  Version number D / 1 D / 1 D//1\mathrm{D} / 1
  Method for determination of tetrahydrofuran peroxide content   Page 47 / 60 47 / 60 47//6047 / 60
  Controlled state
文件名称 文件编号 KHZY//17-086 版本号 D//1 四氢呋喃过氧化物含量测定方法 页次 47//60 受控状态 | 文件名称 | 文件编号 | $\mathrm{KHZY} / 17-086$ | | :---: | :---: | :--- | | | 版本号 | $\mathrm{D} / 1$ | | 四氢呋喃过氧化物含量测定方法 | 页次 | $47 / 60$ | | | 受控状态 | |

   4.30 .01 moL / L 4.30 .01 moL / L 4.30.01moL//L4.30 .01 \mathrm{moL} / \mathrm{L} Preparation of sodium thiosulfate solution

Use a 10 mL pipette to take sodium 10 mL 0.1 moL / L 10 mL 0.1 moL / L 10mL0.1moL//L10 \mathrm{~mL} 0.1 \mathrm{moL} / \mathrm{L} thiosulfate and place it in a 100 mL volumetric flask. Add purified water to dilute to the scale.
  Note: This solution needs to be prepared on the same day (once a day).

  5. Steps:

5.1 Measure 50 g of THF sample into a 300 mL Erlenmeyer flask.
5.2 Add 20 mL 20 % 20 mL 20 % 20mL20%20 \mathrm{~mL} 20 \% acetic acid and potassium 25 mL 10 % 25 mL 10 % 25mL10%25 \mathrm{~mL} 10 \% iodide solution to the solution continuously, stir, cover with a plug and leave in the dark for 30 minutes.
5. After 330 minutes, titrate with sodium 0.01 moL / L 0.01 moL / L 0.01moL//L0.01 \mathrm{moL} / \mathrm{L} thiosulfate solution until the light yellow color disappears, and note the consumption of sodium thiosulfate V (mL).

  6. Presentation of the results of the analysis:

The peroxides in tetrahydrofuran are H 2 O 2 H 2 O 2 H_(2)O_(2)\mathrm{H}_{2} \mathrm{O}_{2} counted, and the analysis results are calculated according to the following formula:
过氧,化物 % = ( V − V 0 ) × C × 34 × 0.1 m  过氧,化物  % = V − V 0 × C × 34 × 0.1 m " 过氧,化物 "%=((V-V_(0))xx C xx34 xx0.1)/(m)\text { 过氧,化物 } \%=\frac{\left(V-V_{0}\right) \times C \times 34 \times 0.1}{m}过氧化物
where V 0 V 0 V_(0)\mathrm{V}_{0} – the volume of thiosulfate consumed by the blank, mL m mL m mLquadm\mathrm{mL} \quad \mathrm{m} – the mass of the sample, g
   V – The volume of sodium thiosulfate consumed by the sample, mL
   C - concentration of sodium thiosulfate, moL/L
34 – molar mass of peroxide, g / moL g / moL g//moL\mathrm{g} / \mathrm{moL}
The arithmetic mean of the results of the two replicates was taken as the result of the sample. Calculated to 3 decimal places, the result is reserved for 2 digits.

  7. Allowable error:

  Absolute difference in parallel determination 0.1 % 0.1 % 0.1%0.1 \% .

  8. Relevant Records:

8.1 R/KH17-083 "Original Record of Determination of Tetrahydrofuran Peroxide Content"