Determination of trace moisture in fluoroalkanes for industrial use (1)

1 Scope

This standard specifies the test methods for the determination of trace moisture in fluoroalkanes for industrial use: Karl Fischer method-one-volume method, Karl Fischer method-coulometric method and electrolysis method

This standard applies to the determination of trace moisture in industrial fluoroalkanes

2 Normative references

The clauses in the following documents have become the clauses of the wooden standard through the reference of this standard

GB/T6283-1986 Determination of water content in chemical products Karl Fischer method (general method)

GB/T6682-1992 Analysis laboratory water specifications and test methods (GB/T6682-1992, neqISO3696: 1987)

3 general rules

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4 Sampling and sample pretreatment·

According to the corresponding product standard regulations

5 Test method

5.

Some test procedures specified by the test method may lead to dangerous situations

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5.

The water in the sample reacts quantitatively with Karl Fischer reagent, and the Karl Fischer reagent is calibrated accurately with water in advance, and the end point is judged by the "dead stop"

Reaction formula: H ₂ O+I ₂ +SO ₂ +3C ₅ H ₅ N+CH ₃ OH=2C ₅ H ₅ N·HI+C ₅ H ₅ NH·SO ₄ CH ₃ (light brownish yellow)

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Figure 1 Schematic diagram of sampling cylinder

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Figure 2 Schematic diagram of trace moisture analyzer

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4 Sampling needle: the length of the needle is 150mm～200mm, the inner diameter is 0.
5mm～0.
7mm, the schematic diagram is shown in Figure 3
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Figure 3 Schematic diagram of the injection needle

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5 Balance; the maximum weighing is not less than 3000g, and the division value is 0.
1g
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6 Electronic balance: the graduation value is 0.
0001g
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7 Micro syringe: 10uL
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8 Glass syringe: not less than 5mL
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9 Micro burette: 5mL
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Related link: Measured value of relative mass correction factor of each component of fluoromethane