Some standard content:
National Standard of the People's Republic of China
Phthalic anhydride
Phthalic anhydride
1 Subject content and scope of application
GB/T 15336-94
This standard specifies the technical requirements, test methods, inspection rules, and requirements for marking, packaging, transportation and storage of phthalic anhydride. This standard applies to phthalic anhydride prepared by air oxidation of ortho-xylene in the presence of a catalyst. Phthalic anhydride is mainly used in industries such as plastics, paints, dyes, and chemical fibers. Tree formula:
Molecular formula; C, H.0s
Relative molecular mass: 148.12 (according to the 1989 international relative atomic mass) Reference standards
Chemical reagents Preparation of standard solutions for titration analysis (volumetric analysis) Chemical reagents Acid-base indicators General method for determination of pH color range GB 604
General method for colorimetric determination of chemical reagents
GB/T2385 General method for determination of crystallization point of dye intermediates GB7531 Determination of ash content of organic chemical products 3'Technical requirements
The quality of phthalic anhydride shall meet the requirements of the following table: Item
Melting color (color number)
Thermal micro-fixed color (color guide)
Crystallization point, ℃
Approved by the State Administration of Technical Supervision on December 22, 1994Superior product
First-class product||tt ||White flaky or crystalline powder
Qualified product
White with other hues
Flake or crystalline powder
1995-10-01Implementation
Purity, %
Free acid content, %
Ash content, %
4 Test method
4.1 Appearance
Determined by visual method
4.2 Determination of melt color
4.2.1 Reagents and instruments
4. 2. 1. 1
Hydrochloric acid (GB622);
Cobalt chloride (GB1270);
4. 2. 1. 2
4. 2. 1. 3
Potassium chloroplatinate:
GB/T 15336-94
Superior product
Qualified product
4.2.1.4 Electric aluminum block heater: adjust the temperature to 170±3℃, with a hole of 20mm in diameter and 150mm in depth for placing colorimetric tube; 4.2.1.5 Colorimetric tube, 170mm in length, 17mm in inner diameter, and 25ml in volume. Its ground-mouth stopper, 4.2.2 Preparation of platinum-cobalt standard solution: proceed as specified in GB605. 4.2.3 Determination steps
Weigh about 29g of finely ground phthalic anhydride sample (its melted volume is equivalent to 25mL). Place it in a dry, clean colorimetric tube, and place the colorimetric tube in a heater preheated to 170°C to completely melt it. Take out the colorimetric tube and compare it with the same volume of color standard solution along the axial direction under a white background. If the color of the sample is close to that of the standard solution (other hues are allowed), the number of the standard chromaticity is the chromaticity number of the sample. When the hue of the test solution is not comparable to that of the standard solution during chromaticity measurement, it is generally treated as a downgrade. 4.2.4 Allowable difference: 5 for within 40, 10 for 40~-100, and 25 for 125250. 4.3 Determination of thermal stability chromaticity
Move the sample whose melting chromaticity was determined in 4.2 quickly to a heater preheated to 250℃, keep it at this temperature for 1.5 hours, and then take it out for color comparison with the standard solution.
4.4 Determination of crystallization point
Perform according to the provisions of GB/T 2385.
4.5 Determination of purity
4.5.1 Reagents and solutions
4.5.1.1 Sodium hydroxide (GB629): analytical grade, c(NaOH)=0.25mol/L standard solution, prepared and calibrated according to the provisions of GB601:
4.5.1.2 Phenolic acid (GB10729): 1g/I. Ethanol solution. Prepare according to GB604. 4.5.2 Determination steps
Weigh about 0.6g (accurate to 0.0002g) of ground phthalic anhydride sample, place it in a 250mL conical flask, add 80mL of freshly boiled distilled water, cover it with a stopper with an air cooling tube, and heat it over boiling water to dissolve it. When it cools down slightly, stop heating, rinse the cooling tube with 20mL of boiled distilled water, quickly cool it to room temperature, add 2-3 drops of phenolic acid indicator, and titrate the solution with standard sodium hydroxide until the solution turns slightly red, which is the end point. 4.5.3 Expression and calculation of results
GB/T 15336-94
Phthalic anhydride purity mass basis percentage X. shall be calculated according to formula (1): X: - CI YIX 0.074 06
X 100 --0.89X,
Wherein: "—
concentration of sodium oxychloride standard titration solution, mol/L, V·volume of sodium hydroxide standard titration solution consumed in titration, mL.;
0.074 06—mass of phthalic anhydride in grams equivalent to 1.00 ml of sodium hydroxide standard titration solution Lc(NaOH)=1.000 mol/1.];
m,---mass of the sample, g
X, -according to 4.6 The mass percentage of free acid determined is %. 4.5.4 Allowable difference
The difference between parallel determination results should not be greater than 0.1%. The arithmetic mean of the parallel determination results shall be taken as the determination result. 4.6 Determination of free acid content
4.6.1 Reagents and solutions
4.6.1.1 95% ethanol (G679);
4.6.1.2
4.6.1.3
4.6.1.4
4.6.1.5
4.6.1.6
4.6.1. 7
Acetone (GB686)
Bisphenol blue (IIG31224), 4g/L ethanol solution: Potassium hydroxide (GB2306), 0.5mol/L ethanol solution: Phenolic acid (GB 10729), 10 g/L, ethanol solution: Isophthalic acid (HG 3-986):
Potassium o-phthalate,
2 Preparation and calibration of neutral potassium o-phthalate standard titration solution 4.6.2
0.5 mol /L. Preparation of potassium hydroxide ethanol solution 4. 6.2. 1
Weigh 28g potassium hydroxide, dissolve it in a 11.5L volumetric flask, add 50mL water, and then use 95% ethanol to dilute it to 11.5L and clarify it. 4.6.2.2 Preparation of neutral potassium phthalate standard titration solution Weigh 16.62g potassium phthalate (accurate to 0.002g), put it in a 1L volumetric flask, add 51mL water and 190mL 95% ethanol. If the solution is turbid, add distilled water and shake it continuously to make it clear. Then add 0. 400mL of 5mol/L potassium hydroxide ethanol solution. Dilute to 1L with distilled water. This solution is blue for bromophenol blue indicator and yellow for bromophenol acid indicator. 4.6.2.3 Calibration of neutral potassium phthalate standard titration solution Weigh 0.05g of phthalic acid (accurate to 0.0002g) in a 250mL conical flask, add 50mL of acetone to dissolve it completely. Then add 6 drops of bromophenol blue indicator and titrate with neutral potassium phthalate standard titration solution until it turns blue. The titer of neutral potassium phthalate standard titration solution is calculated according to formula (2): t
Where: T is the titer of neutral potassium phthalate standard titration solution, t/mL, mass of phthalic acid
is the volume of neutral potassium phthalate standard titration solution consumed, mL. V,
4.6.3 Operation steps
Weigh 5g of ground phthalic anhydride sample (accurate to 0.001g), put it in a 250ml conical flask, add 50ml of acetone to make it completely dissolved. Then add 6 drops of bromophenol blue indicator and titrate with neutral potassium phthalate standard titration solution until it turns blue. 4.6.4 Expression and calculation of resultsbZxz.net
The mass percentage of free acid X, (calculated as phthalic acid) is calculated according to formula (3): TV
Where: T-titre of neutral potassium phthalate standard titration solution, g/ml. V,-volume of neutral potassium phthalate standard titration solution consumed, mL; ms-mass of phthalic anhydride sample, g. 4.6.5 Allowable error
The difference between parallel determination results should not be greater than 0.02%. The arithmetic mean of the parallel determination results shall be taken as the determination result. 4.7 Determination of ash content
According to the provisions of GB7531. The sample weight is 10g (accurate to 0.001g), slowly heated in evaporating blood or porcelain until the sample is completely sublimated, and burned in a high-temperature furnace at 650±25℃ to constant weight. 5 Inspection rules
All items specified in the technical requirements table of this standard are factory inspection items. 5.1 Sampling method
The uniformly tested products are considered as a batch. Samples are taken from 10% of the total number of packages of each batch of products + small batch products shall not be less than 3 bags. When sampling, use a clean and dry sampling cloth to take samples from the upper, middle and lower parts of the packaging bag, and the total amount of samples shall not be less than 500g. Mix the samples carefully, divide them into two clean and dry ground-mouth bottles, seal them with paraffin, and stick labels on the bottles, indicating the manufacturer name, product name, batch number, and sampling date. One bottle is inspected by the inspection department, and one bottle is kept for 1 month for reference. 5.2 Inspection by the manufacturer
Phthalic anhydride shall be inspected by the quality supervision and inspection department of the manufacturer. The manufacturer shall ensure that all phthalic anhydride shipped out of the factory meets the requirements of this standard. Each batch of phthalic anhydride shipped out of the factory shall be accompanied by a quality certificate in a certain format, including: manufacturer name, product name, trademark, grade, weight, batch number, production date and proof of compliance with this standard. 5.3 Acceptance by the user
The user has the right to accept the received phthalic anhydride in accordance with the provisions of this standard. 5.4 Re-inspection
If one of the indicators does not meet the requirements of this standard, re-samples shall be taken from twice the amount of packaging for inspection. Even if only one indicator of the re-inspection result does not meet the requirements of this standard, the entire batch of products cannot be inspected. 5.5 Arbitration
When the supply and demand parties have objections to the product quality, they can be resolved through negotiation. When arbitration is required, the arbitration institution shall be agreed upon by both parties. During arbitration, arbitration analysis shall be conducted according to the test methods specified in this standard. 6 Marking, packaging, transportation and storage
6.1 Marking
The packaging container of phthalic anhydride should be firmly marked with: manufacturer name, product name, trademark, standard number, grade, net weight, production date, batch number.
6.2 Packaging
Phthalic anhydride is packed in woven bags lined with plastic bags or multi-layer moisture-proof kraft paper bags. Net weight of packaging is 25kg or 50kg6.3 Transportation
GB/T 15336—94
Do not approach fire sources during transportation. Handle with care and avoid exposure to sunlight and rain. Phthalic anhydride is irritating to eyes and skin. Protective equipment should be worn during transportation and safety should be strictly observed. Do not contact with skin or inhale into the body. 6.4 Storage
Phthalic anhydride should be stored in a clean, cool and dry warehouse, avoid sunlight and do not approach fire sources. The storage temperature shall not exceed 40℃. The shelf life of phthalic anhydride products is three months. During the shelf life, the product shall meet the requirements of this standard. Additional remarks:
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the technical jurisdiction of Shenyang Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by Dalian Dye Factory. The main drafters of this standard are Hu Huansong and Zhang He. This standard is equivalent to the Japanese Industrial Standard JIS K4128-84 "Phthalic Anhydride".
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