Potassium Bromate – Preparation, Properties and Uses

Potassium bromate

What Exactly is Potassium Bromate?

Potassium bromate (KBrO3) is a bromate of potassium that appears as white crystals or powder and it is a powerful oxidizing agent which can be easily reduced to bromide. It is the potassium salt of bromate, and it is widely available in high purity. It acts as an effective brominating agent in the substitution reaction.

Note: Potassium bromate(V), Bromic acid, Potassium salt are some of its alternate names.

Properties of Potassium Bromate

Physical Properties of Potassium Bromate 

  1. The molar mass is 167.00 g/mol, and its density is 3.27 g/cm3.
  2. It has a boiling point of 370°C.
  3. It has a melting point of 350°C.

Potassium Bromate’s Chemical Properties

  1. Potassium Bromate has the chemical formula KBrO3.
  2. It has no odor and is a white crystalline powder.
  3. It is only slightly soluble in alcohol and completely insoluble in acetone and ethanol.
  4. It will react with sodium bromate in the presence of dilute acid solution to form bromine. The corresponding chemical equation for potassium bromate is given below.

         BrO3– + 5Br– + 6H+ → 3Br2 + 3H2O

Uses of Potassium Bromate

  1. It is used as a bromine source. Standard potassium bromate can be used directly to make an indefinitely stable standard solution.
  2. It is also used as an antiseptic and astringent in toothpaste, mouthwashes, and gargles.
  3. It is primarily used as a flour and dough conditioner; however, it is also used in analytical chemistry as an oxidizing agent and as a brominating agent.
  4. It aids in the production of uniformly white bread.
  5. It is used to improve flour.
  6. It is used in the manufacture of malt barley.
  7. It is a good source of bromine.

Hazardous Effects of Potassium Bromate

This inorganic compound is a type of chemical that is moderately toxic. Ingestion of potassium bromate results in nausea, vomiting, diarrhea, respiratory stimulation, a drop in body temperature, methemoglobinemia, and renal damage. It has been reported to cause gum inflammation and bleeding when used in toothpaste.

Here Are Some Additional Facts About Potassium Bromate:

  1. It is not permitted or prohibited for use as a food additive in several countries, including the United Kingdom, Canada, Brazil, and the European Union.
  2. The state of California requires potassium bromate-containing foods to bear a warning label.
  3. In laboratory animal studies, potassium bromate exposure increased the incidence of both benign and malignant thyroid and peritoneal tumors.
  4. This compound may also disrupt the genetic material within cells.
  5. To no one’s surprise, the food industry claims potassium bromate is completely safe. It claims that during the baking process, potassium bromate is converted into potassium bromide, a similar but non-carcinogenic chemical.

Why is Potassium Bromate harmful to your health?

In nature, this chemical compound is considered carcinogenic; it has been linked to kidney, thyroid, and gastrointestinal cancer in animals and such substances may also have the potential to harm human reproduction.

What foods are high in Potassium Bromate?

This chemical is mostly found in flour-based foods. It can be found in bread, flour, pizza dough, and buns, among other things. It was identified as a possible human carcinogen by the International Agency for Research on Cancer in 1999. It is also allowed in food as long as it does not exceed 750 parts per million, according to the FDA.

Is Potassium Bromate Soluble in Water?

This chemical compound is an ionic compound. Water and other polar solvents dissolve it. It ionizes in water, producing K+ and BrO3- ions.

Is Bromine Harmful to the Thyroid?

Bromine overexposure can result in hypothyroidism. Bromine displaces iodine in your body when consumed in irregular amounts. Iodine deficiency can increase your risk of developing breast, thyroid, ovary, and prostate cancer.

What happens when Potassium Bromate is heated?

When this compound is heated, a decomposition reaction occurs. It emits highly toxic bromate anion and K2O fumes during decomposition.

What is the effect of Potassium Bromate on humans? 

It has the potential to irritate the lungs. Repeated exposure can lead to bronchitis, which includes a cough, phlegm, and/or shortness of breath.

What is the purpose of Potassium Bromate in bread?

This chemical has a significant effect on food biomolecules such as starch and protein, affecting the extent of gelatinization, viscosity, swelling characteristics, and gluten proteins; it removes the sulfhydryl group, resulting in the formation of disulfide linkages, which improves bread properties.

What is Potassium bromate? This compound is an oxidizing agent. It is an ionic compound and takes the form of white crystals or powder. It is soluble in water at low temperature and becomes more soluble with increasing temperature.

It has been found to cause cancerous tumors in lab animals. It is banned in many countries, including Argentina, Brazil, Nigeria, South Korea, Peru, Sri Lanka and China.

How is Potassium Bromate Prepared?

Potassium bromate is an oxidizing agent that is used to make the dough of wheat breads more stable and stronger. It oxidizes the sulfhydryl groups of proteins, forming disulfide bridges between them. This helps to cross link the protein molecules, making it easier for the gluten structure to trap gas evolved during baking. It is also used as a bleaching agent and to improve the color of food products.

Potassium Bromate can be prepared by a simple chemical reaction, using potassium hydroxide solution and bromine gas. The reaction creates a compound known as potassium bromide, which then decomposes to potassium bromate and water. The crystals are then separated from the liquid by using a cold filter. The liquid can then be discarded, as it contains very little of this inorganic chemical compound.

The crystals are then rinsed two times with ice cold water to remove the remaining solution and to make sure that they are perfectly dry. This chemical is not hygroscopic and will not retain moisture, so it can be stored in a cool place such as the top of a refrigerator. It is a white solid, which can be used in chemical experiments as an oxidizing agent. It reacts energetically with reducing agents such as sulphur and fine metal powders. It is also useful in measuring unsaturation in organic analysis, and it reacts strongly with alkenes that have one or more triple bonds.

Chemical Reactions of Potassium Bromate

It acts by promoting the oxidation of thiol or sulfhydryl groups (S-H) in proteins to disulphide bridges (S-S). These cross-linking reactions increase gluten protein strength, and result in more elastic and stronger dough. It also makes the dough easier to handle, allows it to rise higher and traps gas more effectively.

It is a strong oxidizer, and can react violently with certain chemicals. It is therefore very important to store it separately from other oxidizers such as peroxides, perchlorates and premangantes. Potassium bromate is not compatible with copper and aluminium and should never be stored with them.

The best method of separating this compound from the solution is via electrolysis. The solution is placed on the graphite electrodes and allowed to electrolyse for 5-6 hours. After this time, the solution will be dark green and filled with lots of solid particles from the graphite anode.

The clear liquid is then poured into a beaker and put in the fridge, until it becomes ice cold. This crystallises the majority of the potassium bromate into a white crystalline solid. The rest of the solution can be filtered or decanted. Attempts to use a filter will result in the immediate crystallization of more potassium bromate, so this is not recommended.

Why is Potassium Bromate banned in bread production?

Although it is a powerful oxidizing agent that strengthens dough and allows for higher rising in bread, it has been linked to cancer. It is also banned in many countries, including the European Union, China, South Korea and Sri Lanka. It is a Class 2B carcinogen and has been found to cause mutagenic effects in rodents.

Despite its negative health consequences, the food additive is still used in the United States and in several other countries around the world. The reason for this has to do with a technicality: Potassium bromate was approved before the Delaney Clause in 1958, which stated that any chemical additive that causes cancer in animals would be restricted.

Although it is not safe for human consumption, the FDA has urged bakers to stop using potassium bromate and has required them to list it on the label of their products. However, many bakers are still using it, despite the fact that there are alternative ingredients that can achieve the same results. As a result, consumers are not only being exposed to a potential carcinogen, but they are also being exposed to a dangerous chemical in their workplaces. This poses a serious occupational hazard to the workers and threatens their overall well-being. Moreover, it is also costing the country a lot of money.