GB/T 9104.2-1988 Test method for industrial stearic acid - Determination of saponification value

GB/T 9104.2-1988 Test method for industrial stearic acid Determination of saponification value GB/T9104.2-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for industrial stearic acids-Determination of saponification value
Test methods for industrial stearic acids-Determination of saponification value1 Subject content and scope of application
This standard specifies the method for determining the saponification value of industrial stearic acid. UDC 668.1.012
：543.06
GB 9104.2-88
This standard applies to the determination of the saponification value of industrial stearic acid produced by pressing or distillation after hydrolysis of animal and vegetable fats. 2 Definition
Saponification value: The number of milligrams of potassium hydroxide consumed in saponifying 1g of sample under specified test conditions. 3 Reagents
3.1 Potassium hydroxide (GB2306) 0.5mol/L ethanol solution (ethanol should be refined if necessary). Note: Ethanol sugar preparation method: Weigh 1.5~2g of silver nitrate, dissolve in 3mL of distilled water, and then pour into 1000mL of ethanol to mix. Take another 3g of chemically pure potassium hydroxide, dissolve in 15mL of hot ethanol, cool it, and then inject it into the above ethanol solution and shake it well. After standing to clarify, remove the clarified liquid and distill it again. 3.2 Hydrochloric acid (GB622) 0.5mol/L standard solution. 3.3 Phenolic acid indicator 1% ethanol solution.
4 Instruments
4.1 Constant temperature water bath.
4.2 Burette 50mL.
5 Test procedure
Weigh 2g of sample (accurate to 0.001g) and place it in a 250mL conical flask. Use a pipette to add 50mL of potassium hydroxide ethanol solution, then install a reflux condenser and place it in a water bath (or hot plate) to maintain a slightly boiling state for 1h. Do not let steam escape from the condenser. After removing, add 6 to 10 drops of phenolphthalein indicator, and titrate with hydrochloric acid standard solution while hot until the red color just disappears. At the same time, perform a blank test under interphase conditions. 6 Calculation of results
SV = (V,-V) ×C× 56.1
Wherein: SV—saponification value,
Vz—volume of hydrochloric acid standard solution (Article 3.2) consumed in blank test, mL, Vl——volume of hydrochloric acid standard solution (Article 3.2) consumed in sample test, mL; Approved by the Ministry of Light Industry of the People's Republic of China on April 30, 1988
Implementation on October 1, 1988
GB 9104.2--88
C——concentration of hydrochloric acid standard solution, mol/L, mass of sample, g.
The allowable error of parallel test results is 1.0. Additional Notes:
This standard was proposed by the Ministry of Light Industry of the People's Republic of China. This standard was drafted by the Technical Department of the Daily Chemical Industry Scientific Research Institute of the Ministry of Light Industry. This standard was drafted by the Daily Chemical Industry Scientific Research Institute of the Ministry of Light Industry. 104
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