In the process of absorbing pure water with hydr […]
In the process of absorbing pure water with hydrogen chloride to prepare high-purity hydrogen chloride gas, in addition to the purity of the water used, the factors that determine the purity and concentration of hydrochloric acid are also the key. Let's take a look at the following.
Hydrogen chloride is dissolved in high-purity water or absorbed by high-purity water to become high-purity hydrochloric acid. This absorption process is essentially a process in which hydrogen chloride molecules diffuse across the gas-liquid two-phase interface into water.
Effect of purity of high-purity hydrogen chloride gas: To make a component in the gas contact with the solvent and be absorbed, the gas partial pressure of the component must be higher than the equilibrium partial pressure of the component in the upper part of the solution. The gas partial pressure is a function of the gas composition (that is, the purity of the gas) and the total gas pressure, and the equilibrium pressure is a function of the liquid composition and temperature.
Obviously, at a certain temperature, the dissolution process depends on the purity of the hydrogen chloride partial pressure in the gas phase and the purity of the hydrogen chloride. At the same temperature, the higher the purity of the high-purity hydrogen chloride gas, the higher the concentration of the prepared hydrochloric acid.
High purity hydrogen chloride gas is more conducive to the preparation of high purity hydrochloric acid. At present, high-purity hydrochloric acid is prepared after purification and purification of by-product hydrogen chloride, which not only saves costs, but also avoids the problem that by-product hydrogen chloride is discharged into the air to pollute the environment.