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4 Test method
The reagents and water used in this standard refer to analytical reagents and distilled water or water of equivalent purity when no other requirements are indicated
The standard solutions, impurity standard solutions, preparations and products required in the test are prepared in accordance with the regulations of GB601, GB502, and GB603
4.
Perform according to the method specified in GB3143
4.
4.
At a certain temperature, use an alcohol meter made of ethanol content and its density as a certain function of the relationship
4.
4.
4.
4.
4.
4.
Place the sample in a clean and dry jacketed measuring cylinder, pass water at 20°C into the jacket, slowly put the alcohol meter into the sample, and its lower end should be more than 2cm from the bottom of the cylinder; wait for the temperature of the sample When it reaches 20±0.
4.
Read the ethanol content directly from the alcohol meter
Take the arithmetic mean of the two parallel determination results as the determination result.
4.
2.
5 Tolerance
The difference between the two parallel determination results is not much 0.
1% (V/V)
.
4.
3 Determination of acid content
4.
3.
1 Principle
Using phenolphthalein as an indicator, titrate the acid in the sample with sodium hydroxide standard titration solution
.
4.
3.
2 Reagents and solutions
4.
3.
2.
1 Carbon dioxide- free water
.
4.
3.
2.
2 Sodium hydroxide standard titration solution; c(NaOH)=0.
1mol/L
.
4.
3.
2.
3 Phenolphthalein ethanol solution: 5g/L
.
4.
3.
3 Apparatus
4.
3.
3.
1 Burette: 1mL, division value 0.
02mL
.
4.
3.
3.
2 Pipette: 100mL
.
4.
3.
4 Analysis steps
4.
3.
4.
1 Measure 100 mL of water and place it in an Erlenmeyer flask, add 2 to 3 drops of phenolphthalein solution, adjust to light pink with sodium hydroxide standard titration solution, and keep it for 15 seconds without fading
.
4.
3.
4.
2 Use a pipette to draw 100mL sample into the above solution, titrate with sodium hydroxide standard titration solution to light pink, keep it for 15s without fading as the end point
.
4.
3.
5 Calculation of results
The percentage of acid x 1 : Calculate according to formula (1):
Where: c—concentration of sodium hydroxide standard titration solution, mol/L;
V—The volume of the standard titration solution of sodium hydroxide consumed, mL;
0.
06005— The mass of acetic acid expressed in grams equivalent to 1.
00mL sodium hydroxide standard solution [c(NaOH)=1.
000mol/L] ;
P—The density of the sample at 20℃, g/cm 3
.
Take the arithmetic mean of the two parallel determination results as the determination result
.
4.
3.
6 Allowance
The difference between the two parallel determination results is not more than 0.
0001%
.
Related Links: Industrial Synthetic Ethanol (1)