Some standard content:
Chemical Industry Standard of the People's Republic of China
HG/T2745-1996
Published on April 8, 1996
3-naphthyl
Implementation on January 1, 1997
Published by the Ministry of Chemical Industry of the People's Republic of China WHG/T2745-1996
This standard adopts the Japanese Industrial Standard JIS K4131-1985 "Hydroxynaphthoic Acids (3-Hydroxy-2-naphthoic Acid, 1-Hydroxy-2-naphthoic Acid)" in a non-equivalent manner. The purity and organic impurities in the Japanese standard are determined by liquid chromatography, while the Chinese ministerial standard HG/T2-30480 is determined by chemical method. During the drafting process of the standard, after a series of verification and comparison experiments, it was determined that the high performance liquid chromatography method should be used to determine the content of 2-hydroxy-3-naphthoic acid and organic impurities. In this revision, the use, maintenance and purchase of HPLC instruments are taken into consideration. According to the requirements of relevant manufacturers and users, the chemical analysis method and instrumental analysis method adopted in HG/T2-304-80 are used together, and the technical indicators are determined separately. However, in case of disputes requiring arbitration, the instrumental method shall prevail. In order to be close to international advanced standards, this standard divides product quality into two grades during the revision process, namely superior products and qualified products. The qualified products basically maintain the indicators of the original standard, and the indicators of superior products are basically consistent with the indicators of the Japanese standard. At the same time, in the revision, after verification and comparison experiments, the insoluble matter of sodium bicarbonate was changed to insoluble matter of sodium hydroxide. From the date of implementation, this standard will replace HG/T2-304-80 at the same time. This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the technical jurisdiction of the Shenyang Institute of Chemical Industry of the Ministry of Chemical Industry. This standard is drafted by the Shenyang Institute of Chemical Industry and Tianjin Huashi Chemical Co., Ltd. The main drafters of this standard are: Xu Weifeng, Liu Penglan, Wang Lifeng, and Wang Rong. This standard was first issued in 1965 and revised for the first time in 1980. 1
W.bzsoso.cOm1 Scope
Chemical Industry Standard of the People's Republic of China
Hydroxy-3-naphthoic acid
HG/T2745-1996
Replaces HG/T2-304-80
This standard specifies the requirements, sampling, test methods, inspection rules, and marking, packaging, transportation and storage requirements for 2-hydroxy-3-naphthoic acid (referred to as 2,3 acid). This standard applies to 2-hydroxy-3-naphthoic acid obtained by carboxylation of 2-naphthol. This product is mainly used in dyes, pigments and pharmaceutical industries.
Molecular formula: CiH:O:
Structural formula:
Relative molecular mass: 188.18 (according to the 1991 international relative atomic mass) 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. At the time of publication of the standard, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T601-88 Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB/T604-88 General method for determination of pH color range of chemical reagents acid-base indicators GB/T2384-92 General method for determination of melting point range of dye intermediates GB/T7531-87 Determination of ash content of organic chemical products GB/T13753-92 General method for determination of moisture content of dye intermediates 3 Requirements
2,3 The quality of the acid should meet the requirements of Table 1.
Karl Fischer method and modified Karl Fischer method Table 1 Quality requirements for 2-hydroxy-3-naphthoic acid Items
Initial melting point of dry product, ℃,
2,3 acid content, %
2-naphthol content, %
Approved by the Ministry of Chemical Industry of the People's Republic of China on April 8, 1996
Superior product
Light yellow uniform powder
97.5 (liquid chromatography)
98.3 (chemical method)
1.0 (liquid chromatography)
Qualified product
97.0 (liquid chromatography)| |tt||98.0 (chemical method)
1.0 (liquid chromatography method)
Implemented on 1997-01-01
W.bzsoso, com(5)
1,2 Acid content, %www.bzxz.net
Content of insoluble matter in sodium hydroxide solution, %
Moisture content, %
Ash content, %
HG/T2745—1996
Continued Table 1
Superior products
0.5 (liquid chromatography method)
Items (6) to (8) are regular inspection items and shall be inspected once every quarter. 4 Sampling
Qualified products
0.5 (liquid chromatography)
Sampling is done from 10% bags (or barrels) of each batch (uniform products are considered as one batch), and the number of small batches shall not be less than 3 bags (or barrels). When sampling, use a probe to take samples from the upper, middle and lower parts, and the sampling volume shall not be less than 200g. After mixing the samples evenly, put them in two glass bottles with ground stoppers, label them and indicate: inspection, and one bottle is sealed with paraffin for future reference. 5 Test methods
5.1 Determination of appearance
Visual determination is adopted.
5.2 Determination of initial melting point of dry products
Perform according to the provisions of GB/T2384.
5.3 Determination of 2-hydroxy-3-naphthoic acid content and organic impurity content 5.3.1 Liquid chromatography (arbitration method)
5.3.1.1 Method summary
Liquid chromatography is used with internal standard method for quantitative determination to determine the content of 2-hydroxy-3-naphthoic acid and organic impurity content. 5.3.1.2 Instruments and reagents
Liquid chromatograph
Detector: variable wavelength detector or spectrophotometric detector with equivalent performance; Chromatographic column: inner diameter 3~5mm, length 150~300mm, stainless steel filling column filled with ODSC185~10μm or other brands of ODSC18 stationary phase with equivalent performance;
Data processing machine;
800 type centrifugal precipitator;
Infusion pump: flow range 0.1~5mL/min, flow stability ±2% in UV range; Micro syringe: 25μL, flat head.
b) Reagents
Methanol;
Ammonium dihydrogen phosphate;
2-naphthol: standard substance;
1-teaphenol: standard substance;
W.bzsoso, cOnHG/T2745—1996
2,3 acid: Recrystallize the industrial product 2,3 acid with methanol and activated carbon for more than 5 times, dry at room temperature for 24 hours, and analyze by liquid chromatography under the experimental conditions. The content is greater than 99.9% determined by the area normalization method, which is considered as pure. 1,2 acid: standard substance.
5.3.1.3 Liquid chromatography separation conditions
Analysis conditions are selected according to the different instruments. The following are examples: Stationary phase: chromatographic column filler is Nucleosilc18, particle size 5μm; Mobile phase: methanol + 0.1mol/L diammonium phosphate aqueous solution = 45+55; Chromatographic column: 4.6×250mm stainless steel tube; Detection wavelength: 225nm;
Flow rate: 1.0mL/min;
Column temperature: 40℃ (or room temperature);
Injection volume: 20μL.
5.3.1.4 Preparation of standard solution and determination of correction factor Weigh 0.1500g each of the standard 2,3-acid and 1-naphthol, 0.0500g each of 2-naphthol and 12-acid, and place them in 500mL brown volumetric flasks, dilute to the mark with methanol, shake well and set aside. The standard solution is stored in a brown bottle in a cool, dark place. The shelf life is about one month. During use, pay attention to the change of the correction factor. If there is any change, stop using it. Remove the above-mentioned various standard solutions into 10mL volumetric flasks (see Table 2 for the removal amount), dilute to the scale with methanol, shake well, and analyze under the selected chromatographic conditions to calculate the correction factor and draw the standard curve. Table 2 Preparation of standard solution
Amount of pipette (mL)
2,3-acid
2-naphthol
1,2-acid
1-naphthol
The correction factor of each component is calculated according to formula (1): Where: fi
Correction factor of component i;
Mass of standard substance, g;
Ai—Peak area of standard substance, mm;
ms——Mass of 1-naphthol standard substance, g,3
A,——Peak area of 1-naphthol standard substance, mm. 5.3.1.5 Determination steps
Accurately weigh 0.01% of each of 2,3-acid sample and internal standard 1-naphthol.1000g is placed in a 250mL brown volumetric flask, diluted to the mark with methanol, shaken, and 2mL is transferred to a 10mL volumetric flask with a pipette, diluted to the mark with methanol, shaken, and the solution is centrifuged and precipitated, and 20L is injected under the selected chromatographic conditions for analysis. 5.3.1.6 Calculation of analysis results
Wbzsoso,cOHG/T2745-1996
The mass percentage of 2,3-acid and organic impurities is represented by X, and calculated according to formula (2): Xx=fixxm×100
Wherein: X—the content of component i, %;
the peak area of component i, mm\;
the mass of 2,3-acid sample, g
A.——the peak area of 1-naphthol standard, mm; f.—the correction factor of component 1;
m. The mass of 1-naphthol standard, g.
5.3.1.7 Allowable error
The difference between two parallel determination results, 2,3 acid is not more than 0.4%, 2-naphthol and 1,2 acid is not more than 0.02%. 5.3.1.8 Chromatogram
The chromatogram is shown in Figure 1.
W.bzsoso.cOm5.3.2 Chemical method
HG/T2745—1996
Retention time (min)
1-Solvent peak, 2-Unknown peak, 3-2,3 acid, 4-Unknown peak, 5-2-phenol, 6-1-teaphenol Figure 1 Example of HPLC chromatogram
5.3.2.1 Method summary
2,3 acid reacts with sodium hydroxide to form sodium 2-hydroxy-3-naphthoate. Take 1-naphtholphthalein as the indicator and titrate with sodium hydroxide standard solution to obtain the 2,3 acid content.
5.3.2.2 Reagents and solutions
95% ethanol;
Sodium hydroxide: 0.1mol/L standard titration solution; 5
W.HG/T2745—1996
1-naphtholphthalein indicator: 0.1% solution, prepared according to the provisions of Chapter 3 of GB604. 5.3.2.3 Determination steps
Weigh 0.6g (accurate to 0.0002g) of 2,3 acid sample, place it in a 250mL conical flask, add 50mL 95% ethanol to dissolve, add 1mL 1-naphtholphthalein indicator, and titrate with sodium hydroxide standard titration solution until it turns yellow-green, which is the end point. Perform a blank test under the same conditions.
5.3.2.4 Calculation of analysis results
The mass percentage of 2,3 acid content is represented by X1 and is calculated according to formula (3): Xi=
(VV)) XcX0. 188 2×100:
Wherein: V——the volume of the standard titration solution without sodium hydroxide used for titration of the sample, mL; the volume of the standard titration solution without sodium hydroxide used for blank test, mL; Vi
c—the concentration of the standard titration solution of sodium hydroxide, mol/L; m
the mass of the sample, g;
0.1882——the mass of 2,3 acid expressed in grams equivalent to 1.00mL of the standard titration solution of sodium hydroxide [c (Na0H) = 1.000mol/L].
5.4 Determination of the insoluble matter content in sodium hydroxide solution 5.4.1 Reagents and solutions
Sodium hydroxide: 20g/L solution.
5.4.2 Determination steps
Weigh 2g of the sample (accurate to 0.0002g), place it in a 400mL beaker, add 50mL of 20g/L sodium hydroxide solution, heat to 30℃ to dissolve it, filter the insoluble matter with a G, glass filter, wash with distilled water until the filtrate is no longer yellow, and dry at about 105℃ to constant weight.
5.4.3 Calculation of analysis results
The mass percentage of the insoluble matter content in the sodium hydroxide solution is represented by X2 and calculated according to formula (4): X2
Where: m1 is the mass of the residue after drying, g; m
is the mass of the sample, g.
5.5 Determination of moisture content
Perform according to the provisions of GB/T13753.
5.6 Determination of ash content
Perform according to the provisions of GB/T7531.
6 Inspection plan
6.1 Inspection classification
m1x100
Items (1) to (5) specified in Table 1 are factory inspection items. 6.2 Factory inspection
2-Hydroxy-3-naphthoic acid shall be inspected by the inspection department of the manufacturer in accordance with the requirements of this standard. The manufacturer shall ensure that all products shipped out of the factory meet the requirements of this standard. Each batch of products shipped out of the factory shall be accompanied by a quality certificate in a certain format. If one of the indicators in the inspection results does not meet the requirements of this standard, samples shall be taken from twice the amount of packaging for re-inspection. If only one item does not meet the requirements of the standard, the entire batch of 2-hydroxy-3-naphthoic acid cannot be accepted. 6
W.6.3 User acceptance
HG/T2745—1996
The user has the right to inspect the received 2-hydroxy-3-naphthoic acid in accordance with the provisions of this standard to check whether it meets the requirements of this standard.
7 Marking, packaging, transportation and storage
7.1 Marking
The outer packaging container of 2-hydroxy-3-naphthoic acid should be painted with a firm mark, indicating: manufacturer name, product name, registered trademark, standard number, product batch number, production date and net weight. Each batch of packaged products should be accompanied by a quality certificate. The certificate includes: manufacturer name, product name, batch number, production date, product net weight, proof that the product quality meets the requirements of this standard and this standard number. 7.2 Packaging
2-Hydroxy-3-naphthoic acid is packaged in woven bags, iron barrels or wooden barrels lined with plastic bags, with a net weight of 25kg or 50kg per piece. 7.3 Transportation
Prevent exposure and collision during transportation.
7.4 Storage
The product should be stored in a cool, dry and ventilated warehouse7
W.
Wherein: V——volume of standard sodium hydroxide titration solution used for titration of sample, mL; volume of standard sodium hydroxide titration solution used for blank test, mL; Vi
c—concentration of standard sodium hydroxide titration solution, mol/L; m
mass of sample, g;
0.1882——mass of 2,3 acid expressed in grams equivalent to 1.00mL standard sodium hydroxide titration solution [c(Na0H)=1.000mol/L].
5.4 Determination of insoluble matter content in sodium hydroxide solution 5.4.1 Reagents and solutions
Sodium hydroxide: 20g/L solution.
5.4.2 Determination steps
Weigh 2g of the sample (accurate to 0.0002g), place it in a 400mL beaker, add 50mL of 20g/L sodium hydroxide solution, heat to 30℃ to dissolve it, filter the insoluble matter with a G, glass filter, wash with distilled water until the filtrate is no longer yellow, and dry at about 105℃ to constant weight.
5.4.3 Calculation of analysis results
The mass percentage of the insoluble matter content in the sodium hydroxide solution is represented by X2 and calculated according to formula (4): X2
Where: m1 is the mass of the residue after drying, g; m
is the mass of the sample, g.
5.5 Determination of moisture content
Perform according to the provisions of GB/T13753.
5.6 Determination of ash content
Perform according to the provisions of GB/T7531.
6 Inspection plan
6.1 Inspection classification
m1x100
Items (1) to (5) specified in Table 1 are factory inspection items. 6.2 Factory inspection
2-Hydroxy-3-naphthoic acid shall be inspected by the inspection department of the manufacturer in accordance with the requirements of this standard. The manufacturer shall ensure that all products shipped out of the factory meet the requirements of this standard. Each batch of products shipped out of the factory shall be accompanied by a quality certificate in a certain format. If one of the indicators in the inspection results does not meet the requirements of this standard, samples shall be taken from twice the amount of packaging for re-inspection. If only one item of the re-inspection results does not meet the requirements of the standard, the entire batch of 2-hydroxy-3-naphthoic acid shall not be accepted. 6
W.6.3 User acceptance
HG/T2745—1996
The user unit has the right to inspect the received 2-hydroxy-3-naphthoic acid in accordance with the provisions of this standard to check whether it meets the requirements of this standard.
7 Marking, packaging, transportation and storage
7.1 Marking
The outer packaging container of 2-hydroxy-3-naphthoic acid should be painted with a firm mark, indicating: manufacturer name, product name, registered trademark, standard number, product batch number, production date and net weight. Each batch of packaged products should be accompanied by a quality certificate. The certificate includes: manufacturer name, product name, batch number, production date, product net weight, proof that the product quality meets the requirements of this standard and this standard number. 7.2 Packaging
2-Hydroxy-3-naphthoic acid is packaged in woven bags, iron barrels or wooden barrels lined with plastic bags, with a net weight of 25kg or 50kg per piece. 7.3 Transportation
Prevent exposure and collision during transportation.
7.4 Storage
The product should be stored in a cool, dry and ventilated warehouse7
W.
Wherein: V——volume of standard sodium hydroxide titration solution used for titration of sample, mL; volume of standard sodium hydroxide titration solution used for blank test, mL; Vi
c—concentration of standard sodium hydroxide titration solution, mol/L; m
mass of sample, g;
0.1882——mass of 2,3 acid expressed in grams equivalent to 1.00mL standard sodium hydroxide titration solution [c(Na0H)=1.000mol/L].
5.4 Determination of insoluble matter content in sodium hydroxide solution 5.4.1 Reagents and solutions
Sodium hydroxide: 20g/L solution.
5.4.2 Determination steps
Weigh 2g of the sample (accurate to 0.0002g), place it in a 400mL beaker, add 50mL of 20g/L sodium hydroxide solution, heat to 30℃ to dissolve it, filter the insoluble matter with a G, glass filter, wash with distilled water until the filtrate is no longer yellow, and dry at about 105℃ to constant weight.
5.4.3 Calculation of analysis results
The mass percentage of the insoluble matter content in the sodium hydroxide solution is represented by X2 and calculated according to formula (4): X2
Where: m1 is the mass of the residue after drying, g; m
is the mass of the sample, g.
5.5 Determination of moisture content
Perform according to the provisions of GB/T13753.
5.6 Determination of ash content
Perform according to the provisions of GB/T7531.
6 Inspection plan
6.1 Inspection classification
m1x100
Items (1) to (5) specified in Table 1 are factory inspection items. 6.2 Factory inspection
2-Hydroxy-3-naphthoic acid shall be inspected by the inspection department of the manufacturer in accordance with the requirements of this standard. The manufacturer shall ensure that all products shipped out of the factory meet the requirements of this standard. Each batch of products shipped out of the factory shall be accompanied by a quality certificate in a certain format. If one of the indicators in the inspection results does not meet the requirements of this standard, samples shall be taken from twice the amount of packaging for re-inspection. If only one item of the re-inspection results does not meet the requirements of the standard, the entire batch of 2-hydroxy-3-naphthoic acid shall not be accepted. 6
W.6.3 User acceptance
HG/T2745—1996
The user unit has the right to inspect the received 2-hydroxy-3-naphthoic acid in accordance with the provisions of this standard to check whether it meets the requirements of this standard.
7 Marking, packaging, transportation and storage
7.1 Marking
The outer packaging container of 2-hydroxy-3-naphthoic acid should be painted with a firm mark, indicating: manufacturer name, product name, registered trademark, standard number, product batch number, production date and net weight. Each batch of packaged products should be accompanied by a quality certificate. The certificate includes: manufacturer name, product name, batch number, production date, product net weight, proof that the product quality meets the requirements of this standard and this standard number. 7.2 Packaging
2-Hydroxy-3-naphthoic acid is packaged in woven bags, iron barrels or wooden barrels lined with plastic bags, with a net weight of 25kg or 50kg per piece. 7.3 Transportation
Prevent exposure and collision during transportation.
7.4 Storage
The product should be stored in a cool, dry and ventilated warehouse7
W.
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