Determination of carbon dioxide in urea by acid-base titration
The measurement principle of the acid-base titration of carbon dioxide: In the urea production process, the intermediate product carbon dioxide mainly in the form of ammonium carbamate, ammonium carbonate, ammonium bicarbonate presence of ammonia to free ammonia, ammonium carbamate, ammonium carbonate, bicarbonate, The ammonium form exists. Methyl orange was used as an indicator, and the intermediate product was directly titrated with a hydrochloric acid standard solution (titer volume V1), and the total ammonia content was measured. After addition of an excess of barium chloride solution is neutral in the intermediate product, ammonium carbamate, ammonium carbonate, ammonium bicarbonate and ammonium chloride is converted to barium carbonate precipitation, then phenolphthalein as an indicator, titration with a hydrochloric acid standard solution (titer The volume is V2) and the free ammonia content can be measured. (V1-V2) is the volume of the hydrochloric acid standard solution consumed by the combined ammonia, from which the carbon dioxide content in the intermediate product can be calculated.
Assay steps: (1) Add 200-300 mL of deionized water to a 500 mL volumetric flask, install a special rubber stopper (with a vent and sampling tube on the stopper), wipe dry and weigh. Adjust the opening of the sampling valve, discharge it for a moment and connect it to the sample tube, oscillate it quickly, take about 20g sample, stop sampling, close the valve, dry it after cooling to room temperature, and weigh it. Rinse the sample tube with deionized water, dilute to volume, and mix. This solution is A solution. (2) Pipette 5.00mLA solution into an Erlenmeyer flask pre-filled with 50mL water, add 2 drops of methyl orange indicator, use hydrochloric acid standard solution drip to orange red as the end, record the titration volume. (3) to the other suction 5.00mLA was previously filled with 20mL conical flask neutral barium chloride solution, 2 drops of phenolphthalein indicator was added, dropwise with a standard hydrochloric acid solution to the pink end point disappears, the recording titration volume. Then according to a specific formula, calculate the carbon dioxide content. After many studies have shown that this method has high accuracy in determining carbon dioxide content.
This is the content of carbon dioxide in the urea measurement, in addition meteorological monitoring, it is also often used carbon dioxide measurement, then we can be detected by a carbon dioxide detector, is very convenient. The carbon dioxide detector is measured by a sensor and does not require manual operation. The instrument will automatically display the result. In addition, in weather detection, there are temperature and humidity detection, self-reporting temperature and humidity meter, temperature, illuminance detection, can be measured by the temperature illuminance recorder. Meteorological testing is also a very important part of agriculture, which can improve the efficiency of agriculture and increase agricultural income.
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