GB/T 7383-2020 Active National standards

GB/T 7383-2020 Non-ionic surface active agents—Determination of hydroxyl value

Publish Date: 2020-12-14 Implement Date: 2021-07-01 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

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Basic Information

Standard Code: GB/T 7383-2020

Standard Type: National standards

Standard Status: Active

is_force_gb: no

CCS Name: Basic standards and general methods for surfactants

ICS Name: Surfactants and other auxiliary agents

Publish Date: 2020-12-14

Implement Date: 2021-07-01

Pages: 25 pages

Scope

This standard specifies the determination of hydroxyl value in non-ionic surfactants.
This standard is applicable to the determination of hydroxyl value in aliphatic and alicyclic polyalkoxy compounds (addition products of primary aliphatic alcohols, alkylphenols, and epoxy ethane, epoxy propane, and their mixtures with fatty acids), and is suitable for measuring hydroxyl values ranging from 10 to 1,000.
The phthalic anhydride method is applicable to the determination of hydroxyl value in addition products of primary and secondary aliphatic alcohols, alkylphenols, and epoxy ethane, epoxy propane, and their mixtures with fatty acids.
The acetic anhydride method is applicable to the determination of hydroxyl value in addition products of primary and secondary aliphatic alcohols and alkylphenols with epoxy ethane, but is not suitable for determining the hydroxyl value of propylene oxide products.
Near-infrared spectroscopy is applicable to non-ionic surfactants whose hydroxyl value can be determined by the phthalic anhydride or acetic anhydride method.
Substances that may cause interference include:
—— Primary and secondary amines, amides, tertiary alcohols, mercaptans, and epoxides may produce side reactions that affect the accuracy of the method.
—— Long-chain aliphatic acids and esters may produce anhydride that is more stable than phthalic anhydride and acetic anhydride, and it cannot be completely decomposed at the end of the determination.
—— Other free acids may interfere by reacting with sodium hydroxide standard solution, and alkalis including certain tertiary amines may interfere by reacting with the generated phthalic acid and acetic acid.
The presence of epoxides interferes with the determination. If they can be removed by low-temperature vacuum distillation without changing the hydroxyl value, this method is still applicable. The above-mentioned treatment can eliminate the interference of free epoxy eth