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Method for testing hydroxypropylmethyl cellulose methyl substitution degree

A technology of hydroxypropyl methylcellulose and degree of methyl substitution, which is applied in the field of testing the degree of methyl substitution of hydroxypropyl methylcellulose, can solve the problems of being unsuitable for industrial production, demanding instruments, and low sensitivity. Achieve good market application prospects, low instrument requirements, and high sensitivity

Inactive Publication Date: 2015-12-09
DEZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the defects such as harsh instrument requirements, low sensitivity, cumbersome operation, high cost, and unsuitability for industrialized production of the test method for the methyl substitution degree of hydroxypropyl methylcellulose in the prior art, And provide a kind of test method of methyl substitution degree of hydroxypropyl methylcellulose

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Step 1: Accurately weigh 0.2498g of HPMC (produced by Dow Chemical Company, USA) and dissolve it in 250mL of distilled water to prepare a HPMC solution. Dilute the HPMC solution to half of the original concentration, and draw about 0.5mL of the solution into a 25mL stoppered colorimetric tube. Slowly add 2mL of concentrated sulfuric acid (mass concentration is 95.5%, said mass concentration refers to the percentage of the mass of sulfuric acid in the total mass of sulfuric acid solution) along the tube wall, and shake from time to time, pipette 0.5mL of the above hydrolysis solution into a 50mL volumetric flask , add 2mL potassium permanganate solution (the mass volume concentration of described potassium permanganate solution is 3g / mL, described mass volume concentration refers to the quality of potassium permanganate and potassium permanganate solution when ice bath The ratio of volume. Described potassium permanganate solution is that 12% phosphoric acid adds distill...

Embodiment 2

[0040] Step 1: Accurately weigh 0.2488g of HPMC (manufactured by Dow Chemical Company, USA) and dissolve it in 250mL of distilled water to prepare a HPMC solution. Dilute the HPMC solution to half of the original concentration, and draw about 0.5mL of the solution into a 25mL stoppered colorimetric tube. Slowly add 2mL of concentrated sulfuric acid (mass concentration is 98.5%, said mass concentration refers to the percentage of the mass of sulfuric acid in the total mass of sulfuric acid solution) along the tube wall, and shake from time to time, pipette 0.5mL of the above-mentioned hydrolysis solution into a 50mL volumetric flask , add 2mL potassium permanganate solution (the mass volume concentration of described potassium permanganate solution is 5g / mL, described mass volume concentration refers to the quality of potassium permanganate and potassium permanganate solution when ice bath The ratio of volume. Described potassium permanganate solution is that 18% phosphoric aci...

Embodiment 3

[0045] Step 1: Accurately weigh 0.5152g of HPMC (manufactured by Dow Chemical Company, USA) and dissolve it in 500mL of distilled water to prepare a HPMC solution. Dilute the HPMC solution to half of the original concentration, and draw about 0.5mL of the solution into a 25mL stoppered colorimetric tube. Slowly add 2mL of concentrated sulfuric acid (mass concentration is 96.5%, said mass concentration refers to the percentage of the mass of sulfuric acid in the total mass of sulfuric acid solution) along the tube wall, and shake from time to time, pipette 0.5mL of the above-mentioned hydrolysis solution into a 50mL volumetric flask , add 2mL potassium permanganate solution (the mass volume concentration of described potassium permanganate solution is 4g / mL, described mass volume concentration refers to the quality of potassium permanganate and potassium permanganate solution when ice bath The ratio of volume. Described potassium permanganate solution is that 15% phosphoric aci...

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Abstract

The present invention discloses a method for testing hydroxypropylmethyl cellulose methyl substitution degree. The reaction step comprises 1, oxidation of a hydroxypropylmethyl cellulose solution and a potassium permanganate solution is performed in the presence of sulfuric acid and phosphoric acid at -5 to 0 DEG C; 2, a reaction liquid obtained by the step 1 and sodium bisulfate are mixed, added with concentrated sulfuric acid and a discoloration acid solution while shaking, and reacted at 55 ~ 65 DEG C, wherein the discoloration acid is 1,8- dihydroxy naphthlene -3,6- disulfonic acid; and 3, the reaction liquid obtained in the step 2 is diluted to 0.3 time to 0.8 time of the original solution concentration, and the absorbance at 570nm wavelength of the solution is tested. The test method is low in instrument requirement, high in sensitivity, high in accuracy, simple in operation, and low in cost, can quickly and efficiently determine hydroxypropylmethyl cellulose methyl substitution degree, and has a good market prospect.

Description

technical field [0001] The invention relates to a method for testing the methyl substitution degree of hydroxypropyl methylcellulose. Background technique [0002] Hydroxypropyl methyl cellulose (HPMC) is a kind of methyl cellulose modified by propylene oxide, which is obtained by reacting cellulose with two etherifying agents, methyl chloride and propylene oxide, after alkalization. It is widely used in many fields such as petrochemical, building materials, ceramics, textiles, food, daily chemicals, synthetic resins, medicine and electronics, and has a good development prospect. The chemical structure of HPMC determines its performance, and the methoxy group of HPMC, hydroxypropoxyl content and ratio have certain influence to the water solubility of product, water retention capacity, surface activity and gel temperature (referring to literature: LarssonM, ViridenA, Stading M, et al. The influence of HPMC substitution pattern non solid state properties. Carbohydrate Polymer...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/31G01N1/28
Inventor 顾相伶孙汉文刘耀林宋新峰华玉山
Owner DEZHOU UNIV
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