GB/T 8570.6-1988 Determination of liquid anhydrous ammonia oil content by gravimetric method and infrared spectrometry
Some standard content:
National Standard of the People's Republic of China
Liquid anhydrous ammotia-Determination of oil content--Gravimetric and Infra-red, fnethods UDC 661.518
GB 8670.6-88
SpectrametricbzxZ.net
This standard is equivalent to the international standard IS 0 7106-85 "Liquid anhydrous ammotia for industrial use-Determination of oil content--Gravimetric and Infra-red".
This standard specifies two methods for determining the non-selective oil content in liquid anhydrous ammotia (liquid ammonia) at about 105°C, namely, gravimetric method and infrared spectroscopy. When the content of oil determined by gravimetric method is less than 5mg/kg, it shall be reported as less than 15tng/kg, or determined by infrared spectroscopy. 1 Reference Standards
GB8570.1. Liquid anhydrous ammonia laboratory sample collection GB8570.3 Determination of liquid anhydrous ammonia residue content by gravimetric method 2 Principle
After evaporating the liquid ammonia sample at room temperature, use carbon tetrachloride to extract the oil in the evaporation residue. After heating to remove carbon tetrachloride, weigh the remaining residue; or measure the absorbance of organic matter at a wavelength of about 3.42um (corresponding to the strongest absorption band of asymmetric vibration of CH group). * In the analysis of test liquids
, unless otherwise specified, only analytical reagents, distilled water or water of equivalent purity can be used. 3.1 Refrigerant, a mixture of solid carbon dioxide (dry ice) and industrial alcohol, with a refrigeration temperature of -35 to 40°C; $, sulfuric acid (GB 625-77): about 20% (m/m) solution; 8.3 Hydrochloric acid (GB622-77): about 10% (m/m) solution; .4 Carbon tetrachloride (GB688-79), when used for infrared spectroscopy, should not contain other light-absorbing impurities near the 3.42μm wavelength of the analyzed particle. Please note that carbon tetrachloride is toxic. Avoid inhalation of its vapor and avoid contact with skin and clothing. 3.5 Methyl red (HG3-958-76): 1g/L 95% (V/V) ethanol solution: 1.6 Paraffin oil standard solution: 0.5mg/ml carbon tetrachloride solution; weigh 0.050g of spectrally pure paraffin oil (usually n-1 hexadecane), weigh to 0.0001, put it in a 100ml beaker, add about 50ml of carbon tetrachloride, wait for it to dissolve, transfer all of it into a 100ml volumetric flask, dilute to the scale with the same carbon tetrachloride, and shake it. Silicone grease, used to lubricate the glass piston.
4 Techniques
Performance of the bandgap
4.1 Sample sampling device
Use a broken glass test tube with a total volume of about 550ml and a mark at 400ml (see figure) instead of a glass test tube with a total volume of about 150ml and a mark at 100ml. Assemble the instrument according to the provisions of 4.1 of GB8570.3 and its attached drawings. Approved by the Ministry of Chemical Industry of the People's Republic of China No. 87-12-02 and implemented on September 1, 1988
GB 8570.0-88
Test tube with stopper
4.2 Constant temperature [drying box: Temperature control requirement is 105 ± 2℃. 4.3 Platinum hair dish: about 70ml volume.
4.4 Infrared spectrophotometer: equipped with a sealed quartz cell with a thickness of 1cm. 5 Sampling
Take laboratory samples according to the provisions of GB85701. 6 Operating procedures
6.1 Sample collection 17
Weigh the mass of two conical flasks A and B, each filled with about 500ml sulfuric acid solution (3.2) and 2 drops of methyl red solution (3.5), and connected with connecting tubes starting from the connection point 5, and weigh to 0.1&. Immerse the stoppered test tube in the refrigerant (3.1) in the Dewar flask to three-quarters of the depth, and connect conical flasks A and B. The following operations are carried out according to 6.1 of GB8570.3 from "rotate piston 3 to seal the test tube, 1 and 2 ends...", and take 400ml of liquid hydrogen sample from the test tube.
6.2 Oil separation
In a constant temperature drying oven at 105±2℃, heat the platinum evaporator III for 1h, then transfer it to a dewar containing active silica gel and cool it, weigh it, and weigh it to 0.0001g
Take out the test tube containing the sample from the Dewar flask, and let the hydrogen evaporate slowly through the 2 ends at room temperature until the bottom of the test tube is an evaporation residue composed of ammonia water, oil and other non-volatile substances at room temperature. Sampling instructions,
1IS07106 Take 200ml of sample, this standard is revised to 00ml according to the technical requirements of superior oil containing 5mg/kg or less. The concentration of the acid absorption solution used is increased by 1 times, which is 20mg/kg (m/kg).
GB 8570.6-86
After adding a little water and 1 drop of methyl red solution (3.5) to the test tube, add hydrochloric acid solution (3.3) until the evaporation residue is acid. Note: When using infrared spectroscopy, use the external small reagent method instead. Add 10ml of phosphorus tetrachloride (3.4), stir, transfer to the separatory funnel, wash the test tube with m-carbon tetrachloride (10ml each time) 2 to 3 times to wash the oil in the test tube, and collect the washing liquid in the separatory funnel. After shaking the separatory funnel vigorously, wait for the organic matter to settle, filter slowly through dry filter paper, collect the filtrate and add a known mass of platinum evaporation blood (4.3).
Add 10ml carbon tetrachloride (3.4) to the separatory funnel, shake it with hot water to allow the organic matter to settle, continue to shake it through the original filter paper, and collect the filtrate in a humidifier.
Wash the filter paper with 10ml carbon tetrachloride (3.4), combine the washing liquid and the collected filtrate. Clinical determination
multiple, shadow, weight plate method
3:1,1 solvent removal and oil weighing In a good fume hood, evaporate the carbon tetrachloride in the platinum evaporation blood (4.3) on a boiling water bath, then transfer it to a constant temperature box at 105±2℃ and heat it for 15~20minⅡ. Transfer the zinc precipitate into a desiccator containing active silica gel, cool and weigh to an accuracy of 0.0001%. 2 Result expression
The non-volatile oil content X at 105°C expressed in milligrams (mg/kg) of enzyme per gram is calculated according to formula (1): Xi=
Wherein; m is the mass of the sample [the number of milliliters of liquid ammonia collected in the test tube multiplied by 0.68 (0.68/ml is the density of liquid ammonia) and the sum of the mass increments of the two conical flasks and the connecting tubes attached from the connection point 5, the mass of the empty platinum evaporating blood, and
the mass of the platinum evaporating dish and oil, g.
The arithmetic mean of the parallel determination results is taken as the determination result. ., Model fish, infrared spectroscopy || tt||Reference. Good. Preparation of test solution
Take out the oil obtained by operation in 6.3.1.1 from the evaporator, add 10ml of magnetic tetrachloride (3.4), and transfer it to a bottle after the oil is dissolved. Wash the evaporator with carbon tetrachloride 112 to 3 times (use 10ml each time) to wash away the trace oil contained, add the rinsed solution to the container, dilute to the scale with the same carbon tetrachloride, and shake well. Drawing of standard curve
According to the sample graph in the table below, add the given volume of paraffin oil standard solution (3.6) to a series of 50ml bottles: paraffin oil Dilute the oil standard solution (3.6) to the mark with carbon tetranitride in each volumetric flask and shake well. Corresponding to the wax oil content
GB8570.6-88
After adjusting the analysis wavelength of the infrared spectrophotometer (4.4) to 3.42μm and the absorbance of carbon tetrachloride (3.4) to zero, measure the absorbance of each standard solution respectively.
Note: Because this method has high sensitivity, be careful of foreign grease contamination during operation. Plot the number of milligrams of paraffin oil contained in 50ml standard solution as the horizontal axis and the corresponding absorbance as the vertical axis. Prepare a standard curve. Note: A new standard curve should be drawn for each measurement. 6.8.2.3 Determination of test solution
Perform the same operation as in 6.3.2.2 for determination of standard solution and measure the absorbance of the test solution (6.3.2.1). 8.3.2.4 Expression of results.
Find out the oil content corresponding to the absorbance of the test solution (6.3.2.1) from the standard curve (6.3.2.2) and calculate the 105℃ non-volatile oil content X expressed in milligrams per gram (mg/kg) according to formula (2): #3
Where m is the same as in 6,3.1.2
m3 Oil content in the test solution, mg.
Take the arithmetic mean of the parallel determination results as the determination result. Additional remarks:
This standard is issued by the Shanghai Research Institute of Chemical Industry under the Ministry of Chemical Industry. This standard is funded by the Shanghai Research Institute of Chemical Industry under the Ministry of Chemical Industry and Wujing Chemical Plant. The main drafters of this standard are Gu Yongkang, Jin Zhigen, Yao Bingsheng, Liu Miaode, Zhang Wenwei
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