Some standard content:
Chemical Industry Standard of the People's Republic of China
HG2077-91
Disodium Scarlet Acid
Published on July 17, 1991
Ministry of Chemical Industry of the People's Republic of China
Implemented on January 1, 1992
Chemical Industry Standard of the People's Republic of China
Disodium Scarlet Acid
Subject Content and Scope of Application
HG2077-91
This standard specifies the technical requirements, test methods, inspection rules, and marking, packaging, transportation and storage requirements of disodium scarlet acid. This standard applies to powdered disodium scarlet acid prepared by condensation of J acid and phosgene. This product is mainly used in the dye industry. Structural formula:
Molecular formula: C2HO.NS2Na2
NIICO--NH-
Relative molecular mass: 548.46 (according to the international relative atomic mass in 1987) 2 Reference standards
GB 601 Preparation of standard solutions for chemical reagent titration analysis (volume analysis) 3 Technical requirements
3.1 Appearance: gray-brown uniform powder.
3.2 The quality of scarlet acid disodium salt shall meet the requirements of the following table: Index
Scarlet acid disodium salt content
Free J acid (diazotizable)
Water-insoluble matter content
Test method
4.1 Appearance
Determined by visual method.
4.2 Determination of the content of scarlet acid disodium salt
4.2.1 Principle of the method
Superior grade
%(m/m)
In potassium carbonate medium, scarlet acid disodium salt and p-toluidine diazonium salt are quantitatively coupled. 4.2.2 Reagents and solutions
4.2.2.1 Potassium carbonate (GB1397): chemically pure. 4.2.2.2 Sodium chloride (GB1266): chemically pure. Standard
First grade
4.2.2.3 H acid indicator solution: 10g/L solution. Weigh 1g H2O2, add 150g/L sodium carbonate solution to make 100mL. This solution is now approved by the Ministry of Chemical Industry of the People's Republic of China on July 17, 1991 and implemented on January 1, 1992
HG2077-91
4.2.2.4 Sodium nitrite standard solution: c(NaNO2)=0.5mol/L. Prepare and calibrate according to the method specified in GB601. 4.2.2.5 p-Toluidine hydrochloride standard solution: c(CH,CHNHz·HCI)=0.5mol/L. Preparation: Weigh 54g p-Toluidine, add 104mL hydrochloric acid and a small amount of water to dissolve, then dilute to 100mL and store in a dark place. For calibration, accurately pipette 25.00 mL of the prepared p-toluidine solution, add 20 mL of hydrochloric acid, 175 mL of water, and 5 g of potassium bromide. At 15-20 °C, titrate with sodium nitrite standard solution (4.2.2.4) until the starch potassium iodide test paper turns microscopically blue and maintain for 5 minutes as the end point. The concentration ci of the p-toluidine hydrochloride standard solution is calculated according to formula (1): c·V
Where: c——concentration of sodium nitrite standard titration solution, mol/L; V1—volume of sodium nitrite standard titration solution, mL; V2——volume of p-toluidine standard solution, mL. 4.2.2.6 p-toluidine diazonium salt standard solution: c(CH,CHN2CI)=0.1mol/L. (1)
Preparation: Accurately pipette 50.00mL of p-toluidine hydrochloride standard solution (4.2.2.5) into a 250mL brown volumetric flask, add 5g of potassium bromide, cool to 0~5℃ in an ice-water bath, and add about 50mL of sodium nitrite standard solution (4.2.2.4) pre-cooled to 0~5℃ while shaking. Place in an ice-water bath for 30min. This solution should show a microscopic blue color on starch potassium iodide test paper (the excess of sodium nitrite standard solution should not exceed 0.5mL). Then dilute to the scale with 0~5℃ distilled water. This solution should be stored in an ice-water bath away from light (use within 10h). The concentration c2 of p-toluidine diazonium salt standard solution is calculated according to formula (2): CX50
Where: ci——concentration of p-toluidine hydrochloride standard solution, mol/L. 4.2.3 Analysis steps
(2)
Weigh about 1.4g (accurate to 0.0002g) of powdered disodium salt of scarlet acid into a 300mL beaker, add 2.8g potassium carbonate (4.2.2.1) and a small amount of water to dissolve, then add water to 100mL. Cool to 0~5℃ in an ice-water bath, and titrate with p-toluidine diazonium salt standard solution (4.2.2.6) under stirring. When approaching the end point, add 20g sodium chloride for salting out, and do a seepage circle test on filter paper (medium-speed qualitative). The end point is when the coupling liquid seepage circle contacts the H acid solution and an obvious purple color appears and remains for 3min. 4.2.4 The content of disodium salt of scarlet acid a1 is calculated according to formula (3): 21 = · V, X0.2742 bzxZ.net
C2——concentration of p-toluidine diazonium salt standard titration solution, mol/L; Vs—volume of p-toluidine diazonium salt standard titration solution, mL; mass of disodium salt of scarlet acid,
(3)
0.2742——mass of disodium salt of scarlet acid expressed in grams equivalent to 1.00 mL p-toluidine diazonium salt standard titration solution [c(C,H,CHsN2Cl)=1.000mol/L), name. The difference between the results of two parallel determinations shall not exceed 0.5%, and the arithmetic mean is taken as the determination result. 4.3 Free J acid content
4.3.1 Principle of the method
Free J acid undergoes quantitative diazotization reaction with sodium nitrite in a hydrochloric acid solution medium. 4.3.2 Reagents and solutions
4.3.2.1 Hydrochloric acid (GB622): chemically pure; 4.3.2.2 Sodium carbonate (GB9856) solution: 100g/L solution; 4.3.2.3 Sodium nitrite standard solution: c(NaNO2)=0.1mol/L. Prepare and calibrate according to the method specified in GB601. 4.3.3 Analysis steps
HG2077—91
Weigh about 1g of the sample (accurate to 0.0002g), add 25mL (100g/L) of sodium carbonate solution (4.3.2.2) to dissolve (heat to dissolve if necessary), add 180mL of water, 17mL of hydrochloric acid, and 2g of potassium bromide, cool to 10~15℃, and titrate with sodium nitrite standard titration solution (4.3.2.3) under stirring until the starch potassium iodide test paper turns microscopic blue, and keep it for 2 minutes, which is the end point. Perform a blank test at the same time. 4.3.4 The content of free J acid (calculated as 100% disodium salt of scarlet acid)2 shall be calculated according to formula (4): c(V.-Vo)X0.2393
m2·ai
wherein:
concentration of standard sodium nitrite titration solution, mol/L; V4——volume of standard sodium nitrite titration solution, mL; V. —volume of standard sodium nitrite titration solution for blank test, mL; (4)
0.2393——mass of J acid equivalent to 1.00mL standard sodium nitrite titration solution [c(NaNO2=1.000mol/L), expressed in grams:
m2——mass of the sample, g;
content of disodium salt of scarlet acid, %.
4.4 Determination of water-insoluble content
4.4.1 Instrument
G3 acid-resistant filter funnel;
Oven: can be controlled at 100~105℃.
4.4.2 Analysis steps
Weigh 2g of sample (accurate to 0.0002g), add 200mL of water, heat and maintain at 50℃, stir to fully dissolve, filter with a constant weight G3 acid-resistant filter funnel, and bake the funnel in an oven at 100~105℃ to constant weight. 4.4.3 The water-insoluble content s is calculated according to formula (5): ms-m×100.
Where: m: — mass of the funnel with water-insoluble matter after drying,; — mass of the G3 acid-resistant filter funnel, g;
m5——mass of the sample, g.
5 Inspection rules
(5)
5.1 Disodium salt of scarlet acid shall be inspected by the inspection department of the manufacturer. The manufacturer shall ensure that all disodium salt of scarlet acid leaving the factory are accompanied by a quality certificate in a certain format.
5.2 The user has the right to verify the disodium salt of scarlet acid received in accordance with the provisions of this standard to verify whether it meets the requirements of this standard.
5.3 Sampling method: Select 10% of the disodium salt of scarlet acid from each batch of samples. The small batch shall not be less than 3 barrels. Use a probe to evenly sample from the top, middle and bottom of the barrel. The total sampling amount shall not be less than 0.5kg. 5.4 Mix the selected samples carefully and put them into two clean and dry ground-mouth bottles, and affix labels with the manufacturer name, product name, batch number, sampling date, etc. One bottle will be inspected by the inspection department and the other bottle will be kept for reference. 5.5 If one indicator in the inspection results does not meet the requirements of this standard, re-sampling should be carried out from the double packaging. If even only one item in the re-inspection results does not meet the requirements of this standard, the entire batch of disodium scarlet acid cannot be accepted. 5.6 When the supply and demand parties have objections to the product quality, the two parties shall negotiate to resolve the issue. 6 Marking, packaging, transportation and purchase and storage
6.1 Disodium scarlet acid is packaged in iron barrels lined with plastic bags, with a net weight of 50kg per barrel. Each batch of packaged disodium scarlet acid should be accompanied by a quality certificate. The certificate shall include the manufacturer’s name, product name, batch number, production date, factory date, product net weight, etc., as well as this standard. 3
HG2077-91
The packaging container shall be firmly marked, including: manufacturer’s name, product name, registered trademark, batch number, production date and 6.2
net weight.
6.3 During transportation, it shall be strictly protected from moisture and rain. 6.4 The product shall be stored in a dry and ventilated place to prevent heat and moisture. Additional remarks:
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People’s Republic of China. This standard is under the jurisdiction of the Shenyang Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Shenyang Chemical Industry Research Institute of the Ministry of Chemical Industry and Tianjin Dyeing and Chemical Plant No. 7. The main drafters of this standard are Zhou Jiyuan, Cao Jiandi and Wang Qiongxuan. This standard is equivalent to the Japanese Industrial Standard JISK4155-63 (confirmed in 1984) "Disodium Red Acid". 4
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