Synthesis database: 1. Potassium chlorate synthesis (via hypochlorite)

Regarding the chemicals and the equipment that is needed, this is one of the most simple ways to synthesize potassium chlorate. Basically, this reaction is based on the thermal decomposition of sodium hypochlorite. After that, via the process of ion exchange and thereby using sodium chlorate, one can obtain potassium chlorate. The main reaction is:

3NaClO(aq) › 2NaCl(aq) + NaClO3(aq)

while the other reaction is shown below:

NaClO3(aq) + KCl(s) › NaCl(aq) + KClO3(aq)

As a source of sodium hypochlorite, a solution used for bleaching was used which contains around 5% of the mentioned compound. Thereby, the mass of NaClO per one liter of this type of bleach, is around 50 grams, which is equal to 0.675 moles. The reaction of thermal decomposition of the hypochlorite shows that from 3 moles of NaClO, one mol of sodium chlorate is produced. When we take into account that in our case, we have 0.675 moles of NaClO, it turns out that we will get around 0.225 moles of NaClO3.

Furthermore, in the reaction that shows the process of ion exchange, we can see that for the synthesis of one mol of potassium chlorate, we need to add one mol of potassium chloride to a mol of sodium chlorate. By doing the math with the already mentioned values, it turns out that we need to add 16.65 grams of potassium chlorude (0.225 moles). To make weighing more simple, we rounded this value to 17 grams.

First, 1000 ml of the mentioned solution of hypochlorite is heated until it starts to boil, preferably in a stainless steel beaker. We leave this solution to boil for around half on hour, until the volume of the solution drops to about 140 ml. After that, the solution is cooled gradually until room temperature is reached. During the cooling, some solid sodium chlorate can be formed. Because of that, the solution can simply be filtered when it has cooled down. The chlorate forms because while cooling, the solution becomes supersaturated. In addition, the commercial liquid hypochlorite solutions also contain a certain amount of sodium chloride. Having in mind that even more NaCl is created in process of thermal decomposition, the supersaturation doesn't come unexpected.

After the solution cooled down, 17 grams of potassium chloride was added, and at the same time, the temperature of the solution is increased gradually. After all the potassium chloride is dissolved, the temperature is still increased until boiling point is reached. After that moment, the solution is taken away from the heat source and is left to cool down to room temperature. Later, the solution is cooled further by placing it in the fridge at the minimal temperature that can be achieved. Already at 0°C, a nice amount of potassium chlorate crystals should be visible.

These crystals are the final product - potassium chlorate. Since they are still in the solution, they need to be filtered. The remaining liquid can be heated again until the volume of the solution is even more reduced. After that, the remaining solution is cooled once again, in order to extract as much crystals from the solution, as possible.

After the mentioned step, the two batches of potassium chlorate can be mixed together. The mass of the crystals that were produced in the described synthesis was 14.1 grams. After the eventual weighing of the KClO3, the crystals are placed in a container, which is than placed in a larger container containing a common dessicant - silica gel. After spending a day in a closed container with silica gel, the potassium chlorate crystals were completely dry and ready to be safely stored.