This standard is applicable to the determination of neutral oil and pyridine base content in crude phenol prepared from coal tar and phenol-containing wastewater, phenol obtained by fractionation, industrial phenol, tri-cresol, m-p-cresol and industrial xylenol. GB/T 3711-1983 Determination of neutral oil and pyridine base content in phenol products GB/T3711-1983 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Phenol products
Method of determination for neutral oilsand pyridine bases contents of phenol productsUDC 647.56:543
GB 3711-83
This standard is applicable to the determination of neutral oil and pyridine base content in crude phenol prepared from coal tar and phenol-containing wastewater, phenol, industrial phenol, tri-cresol, m-cresol and industrial cresol obtained by fractionation. 1 Test Principle
Neutral oil and pyridine base are distilled from the alkaline aqueous solution of the sample. The neutral oil is collected with toluene, and the volume of the collected neutral oil is measured, which is the neutral oil content. The collected hot water fraction and pyridine base in the neutral oil are titrated with a standard hydrochloric acid solution using a toluene orange-xylene cyanol FF ethanol solution as an indicator to calculate the pyridine base content by calculation. 2 Reagents
Sodium hydroxide: analytical grade, 27% solution.
Toluene: analytical grade.
2.3 Standard hydrochloric acid solution: 0.1N, 0.5N or 1N (calibrated with the sodium carbonate method. If the pyridine content is high, it can be titrated with a 1N standard solution). 2.4 Phenolphthalein ethanol solution: 0.5g phenolphthalein is dissolved in 100ml95% (V/V) ethanol, and a drop of dilute sodium hydroxide solution is added to produce a light pink color. Indigo orange-xylene cyanol FF ethanol aqueous solution: 1 methyl cyanol and 1.4g methyl cyanol FF are dissolved in 500ml50% (//V) ethanol.
3 Instruments and equipment
Steaming filling device: as shown!
Figure 1 Distillation instrument Assembly drawing
National Bureau of Standards 1983-05-24 Issued
1984-05-01 Implementation
3.1.1 Glass splash-proof bulb: as shown in Figure 2.
3.1.2 Bubble tube: as shown in Figure 3.
GB3711-83
Figure 2 Glass splash-proof bulb
Figure 3 Bubble tube
Cooling tube: as shown in Figure 4.
GB 3711-48
Outside 23~25
Outside 18~20
Outside point 12-13
Figure 4 Cooling tube
3.1.4 Glass receiver: as shown in Figure 5.
GB 3711—B3
60°±3
That is, ±3”
Figure 5 Glass receiver
GB 3711—88
3.1.5 Distillation flask: made of hard glass, volume 1000ml, as shown in Figure 6. 46±1
Volume 1000ml
Figure 6 Round bottom distillation flask
S-shaped glass bend: as shown in Figure 7.
165-170
Figure 7 S-shaped glass bend
GB 3711-83
3.1.7 Erlenmeyer flask: 500ml, graduated 3.1.8 Burette: 25ml, graduated 0.1ml, 2 pieces. 3.1.9 Pipette: 5ml, 1 piece.
3.1.10 Pipettes: 25ml and 10ml, 1 each. 3.1.11 Gas lamp:
4 Test steps
4.1 Preparation of instruments
, 1.1 Before starting the test, the receiver and flask should be strictly cleaned, usually with detergent, and the scale of the receiver should be washed with detergent, and finally rinsed with distilled water.
4.1.2 In a clean receiver, add distilled water to the lower ball to the scale, then use a pipette to add 3-4 ml of dimethylbenzene, be careful not to let dimethylbenzene drip onto the upper ball wall, and let it stand for use. 4.2 Steaming stuffing
4.2.1 Accurately measure 100 ml of the shaken sample in a 100 ml measuring cylinder, pour it into a 1000 ml distillation bottle, and make sure the sample in the measuring cylinder flows as much as possible. Use the same measuring cylinder to add 170 ml of sodium hydride solution, shake the bottle at the same time, and use this cylinder to add 100 ml of distilled water, thoroughly mix, and add a few pieces of broken porcelain to prevent boiling. 4.2.2 Use a 25ml measuring cylinder to measure 25ml of sodium hydroxide solution and pour it into the bubbler tube. Accurately read the volume of toluene added to the receiver. The instrument is shown in Figure 1
4.2.3 Ensure that the bubbler tube is not blocked, then turn on the cooling water, keep the cooling water in the cooling tube continuously, heat and distill. When the condensate begins to flow out, open the piston at the bottom of the receiver, and keep the toluene liquid column close to 4ml. Distill at a speed of collecting 200ml of distillate within 30-40min. The distillate flows down along the inner surface of the receiver. 4.2.4 If there is solid matter in the distillate in the cooling tube, when the distillate is close to 180ml, turn off the cooling water to melt the condensed solid matter. When the solid matter is completely melted, turn on the cooling water, and when the distillate is close to 200ml, stop heating and let the condensate flow down completely. 4.2.5 During the distillation (or before the condensate is melted), steam is not allowed to escape from the end of the cooling tube. Note: ① Pay attention to safety and explosion prevention during the distillation. ② During distillation, place an asbestos net under the distillation bottle, with a round asbestos of about 50mm in diameter in the middle. ③ Pour out the residual flow while it is hot. If there is a solidified residue, slowly add hot water to the upper part of the bubbler to break it up. If there are lumps at the bottom of the bottle, add dilute sulfuric acid to wash it.
4.3 Determination
4.3.1 Determination of neutral oil
Make the xylene layer in the receiver located at the scale part, let it stand for 15 minutes, and accurately read the volume of the toluene layer. 4.8.2 Determination of pyridine base
Transfer all the aqueous solution and xylene in the receiver to a conical flask and combine them with the distillate. Wash the receiver twice with 20ml of distilled water, add the washing liquid to the conical flask, and add 2 to 3 drops of phenolic acid indicator solution. If the color is red, titrate with 0.1N hydrochloric acid standard solution until the red color disappears. Add 4-6 drops of methyl orange-xylene cyanol FF indicator solution to the above solution or the original solution that has changed color, and titrate with 0.5N hydrochloric acid standard solution. Shake the mixture thoroughly every time you add 1 drop of hydrochloric acid standard solution until the color changes from green to magenta, which is the end point (when measured with a pH meter, the pH is set to 3.7). In general, ① if the crude phenol sample is prone to foaming during the distillation process, which affects the distillation, the sampling volume can be reduced to 50ml. ②) When the pyridine base content is greater than 0.5g/10ml, the sampling volume is reduced to 50ml. ③ When the neutral oil content is greater than 1ml or there are many volatile substances, the sampling volume is reduced to 50ml. @When the sample volume is 50ml for analysis, add 85ml of sodium oxide liquid and then add 185ml of slightly increased water. The other operations are the same as 4.5 Calculation of test resultsbzxz.net
GB 3711--83
5.1 The percentage of neutral oil X (F/V) is calculated according to formula (1): -V.
Wherein, J is the volume of the printed benzene layer in the receiver after decomposition, ml; V2 is the volume of toluene added to the receiver, ml; - the volume of the sample, mi.
5.2 The manganese content X (W/V) of pyridine base is calculated according to formula (2): ×100
V1-A: ×0.079
Wherein: V---the volume of hydrochloric acid standard solution consumed in titration!, ml: N-the equivalent concentration of hydrochloric acid standard solution
0.079——1ml1N hydrochloric acid standard solution is equivalent to the number of grams of 1 pyridine base V--the sample volume, ml.
6 Test error
6.1 Neutral oil
Content
0.$ or less
Pyridine alkali
Content range
0.2 or less
Same test error
shall not exceed
Same laboratory error
shall not exceed
Additional instructions:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by the former director of the Railway Bureau. The main drafter of this standard is Ka Xiaoxian.
Unit: %
Different laboratory errors
shall not exceed
Unit: %
Unconfirmed test error
shall not exceed
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