I. Introduction.
Coal tar is an important chemical raw material, and its moisture content has an important impact on its quality and processing process. Therefore, accurate measurement of the moisture content of coal tar is of great significance to ensure product quality and smooth progress of the production process. In this paper, we will introduce the principle and method of measuring the moisture of coal tar using the toluene method.
The principle of measuring the moisture of coal tar by the toluene method is based on the fact that toluene reacts with moisture under certain conditions to produce a measurable substance. Specifically, when toluene reacts with moisture, a substance called phenol is formed. Phenol is a substance with special properties that can be measured by a specific method to deduce the moisture content in coal tar.
3. The steps of measuring the moisture of coal tar by toluene method.
1.Prepare reagents and equipment.
First of all, you need to prepare toluene, anhydrous calcium chloride, funnels, filter paper, dryers, weighing flasks, balances, ovens and other equipment and reagents. Among them, toluene is used to react with moisture, anhydrous calcium chloride is used to dry coal tar samples, funnels and filter paper are used to filter samples, desiccats are used to keep samples dry, weighing flasks are used to weigh samples and products, balances are used to weigh samples accurately, and ovens are used to dry samples.
2.Sample handling.
Place the coal tar sample in a weighing flask and weigh it accurately with a balance. Then add an appropriate amount of anhydrous calcium chloride, stir well, and place it in a desiccator to dry for a period of time to remove the water in the sample.
3.Reaction process.
Take out the dried coal tar sample, add an appropriate amount of toluene, and stir well. The mixture is then poured into a funnel and filtered with filter paper. At this point, the moisture reacts with toluene to form phenol, which adheres to the filter paper.
4.Product measurement.
Place the filter paper with phenol attached into the weighing flask and weigh it accurately with a balance. It is then placed in an oven to dry for a period of time to remove moisture from the filter paper. Finally, the filter paper was weighed again and the mass of phenol was calculated.
5.Moisture content calculation.
Based on the mass and reaction equation of phenol, the moisture content in coal tar can be calculated. The specific calculation formula is as follows:
Moisture content = (m1 - m2) (m1 - m0) 100%.
Among them, M1 is the mass of the filter paper and phenol before drying, M2 is the quality of the filter paper after drying, and M0 is the quality of the coal tar sample before drying.
IV. Conclusions. The principle of measuring the moisture content of coal tar using the toluene method is based on the properties of toluene reacting with moisture to form phenol. By accurately measuring the quality of phenol, the moisture content in coal tar can be calculated. This method has the advantages of easy operation, accurate measurement and wide range of application. In practical applications, it is necessary to pay attention to the selection and use of reagents and equipment to ensure the accuracy and reliability of measurements.