Does Hydrogen Peroxide Expire?

Yes, hydrogen peroxide does expire, and using expired hydrogen peroxide can be ineffective.

Stabilised hydrogen peroxide refers to a solution of hydrogen peroxide that contains additives that slow down decomposition. Despite this, stabilised hydrogen peroxide will also expire.

As an oxidising biocide, hydrogen peroxide breaks down into water and oxygen at a rate that is dependent on a number of factors. It is important to check the expiration date on the packaging before using hydrogen peroxide or stabilised hydrogen peroxide.



Shelf Life Of Stabilised Hydrogen Peroxide

Not all stabilised peroxide products are equal, EndoSan Stabilised Hydrogen Peroxide is manufactured with a shelf life of three years meaning it will remain stable and effective for the full duration of this time (provided it is stored correctly in the container and in line with the directions on the label).

When dosed into water EndoSan will also remain stable for weeks at both cold and hot temperatures (depending on the bacterial load and quality of the water). Regular hydrogen peroxide will only remain stable for a number of hours.


Why Does Hydrogen Peroxide Decompose?

Hydrogen peroxide is a relatively unstable compound due to the presence of an oxygen-oxygen bond, which is weaker compared to other chemical bonds. This weak bond makes hydrogen peroxide prone to decomposition, the shelf life and longevity of hydrogen peroxide can be affected by several factors, including:



Higher concentrations of hydrogen peroxide tend to expire faster because they are more unstable than lower concentrations. The decomposition process of hydrogen peroxide occurs when its molecules break down into water and oxygen. The higher the concentration of hydrogen peroxide, the more unstable the molecules are, and the more likely they will break down into water and oxygen. This is not the case with EndoSan Stabilised Hydrogen Peroxide due to the advanced stabilisation of the product.


Temperature can play a significant role in the expiration of hydrogen peroxide. Higher temperatures can accelerate the decomposition process of hydrogen peroxide, causing it to expire more quickly.

This is because high temperatures cause the molecules of hydrogen peroxide to vibrate more vigorously, which can cause them to break down into water and oxygen more rapidly. As a result, hydrogen peroxide is best stored in cool, dark places away from any heat sources, such as radiators, ovens, or bright sunlight.

On the other hand, lower temperatures can help to slow down the decomposition process, which can prolong the shelf life of hydrogen peroxide. However, it is important to store hydrogen peroxide at temperatures above freezing point since freezing can damage the container or affect the potency of the solution. The ideal storage temperature for hydrogen peroxide is typically between 2°C to 18°C (35°F to 65°F).

Exposure to light

Ultraviolet (UV) light, in particular, can cause hydrogen peroxide to break down into water and oxygen more quickly than it would in the absence of light. This is because UV light energy can excite the molecules of hydrogen peroxide, making the bonds between them more unstable and prone to breakage.

As a result, it is best to store hydrogen peroxide in opaque containers that protect it from light, especially direct sunlight. Transparent or translucent containers can allow light to penetrate into the solution, which can accelerate the decomposition process of hydrogen peroxide, causing it to expire sooner. 


Contamination with foreign substances, such as dirt or organic matter, can accelerate the decomposition process. When hydrogen peroxide is contaminated, it can react with the contaminant and accelerate the decomposition process, causing it to expire more quickly. This is because the contaminants can act as catalyzers, which can speed up the reactions of decomposition.

Contamination can occur when hydrogen peroxide comes into contact with organic or inorganic materials, such as dirt, dust, rust, or metal ions. In addition, contamination can also occur through improper storage or handling of the solution.To avoid contamination, it is advisable to store hydrogen peroxide in clean, dry containers that are free of any debris or residues. Also, be sure to use clean tools when handling hydrogen peroxide and avoid exposing it to materials that may react with it.


Natural Decomposition of Hydrogen Peroxide

In the absence of a catalyst, hydrogen peroxide decomposes naturally and slowly over time. This process is known as spontaneous decomposition. When hydrogen peroxide breaks down, it forms water (H2O) and oxygen gas (O2) as by-products. The reaction can be represented by the following equation:

H2O2 -> H2O + O2

The decomposition and expiry process of hydrogen peroxide molecules

The natural decomposition is accelerated when exposed to the catalysts mentioned above, which provide the energy necessary to break the oxygen-oxygen bond.


What Catalyst is Used in the Decomposition of Hydrogen Peroxide?

In the laboratory, the most common catalyst used for the decomposition of hydrogen peroxide is a substance called manganese dioxide (MnO2). Manganese dioxide is a black, powdery compound, and it acts as a surface catalyst, meaning it provides a suitable surface for the hydrogen peroxide molecules to interact with.


Why do Catalysts Speed Up Reactions?

Catalysts are substances that enhance the rate of a chemical reaction without undergoing any permanent change themselves. They achieve this by providing an alternative reaction pathway with a lower activation energy. In simpler terms, catalysts make it easier for the reactant molecules to collide and react, thus speeding up the overall process.


How Does Hydrogen Peroxide Decompose in Chemical Reactions?

The decomposition of hydrogen peroxide in the presence of a catalyst follows a different reaction pathway compared to natural decomposition. The manganese dioxide catalyst provides sites where hydrogen peroxide molecules can interact and react, without being consumed in the process.

The manganese dioxide catalyst acts as a surface onto which the hydrogen peroxide molecules can adsorb, forming bonds with the manganese atoms. This weakens the oxygen-oxygen bond within the hydrogen peroxide, making it more susceptible to breaking.

Once the bond is weakened, the reaction proceeds as follows:

  1. The weakened oxygen-oxygen bond breaks, forming hydroxyl radicals (OH•).
  2. These highly reactive hydroxyl radicals react with other hydrogen peroxide molecules, breaking their bonds as well.
  3. This chain reaction continues until most of the hydrogen peroxide has decomposed, resulting in the formation of water and oxygen gas.

The presence of the catalyst allows the decomposition reaction to occur at a faster rate compared to natural decomposition, enabling efficient use of hydrogen peroxide in various applications.

Storage Requirements and Conditions of Hydrogen Peroxide

Proper storage of hydrogen peroxide is essential to prolong its shelf life and prevent it from expiring before its intended date.

It is highly recommended that Hydrogen Peroxide, and Stabilised Hydrogen Peroxide is stored in the original container it was purchased in making sure to keep the label, and particularly the hazard and precautionary statements sections, in good readable condition.

All EndoSan Stabilised Hydrogen Peroxide products are produced and stored in UN approved HDPE (High Density PolyEthylene) packaging only. The packaging is coloured dark blue to reduce exposure to UV and the caps are vented to ensure that any oxygen released during natural decomposition doesnt cause the container to bloat or fail.

UN approved packaging is marked with specific coding to determine its suitability for storing hydrogen peroxide, below is an example of the coding from the drums used to store EndoSan Stabilised Hydrogen peroxide and a breakdown of what the coding relates to:

UN Approved Packaging example coding for appropriate storage of Hydrogen Peroxide

  1. UN symbol – standard on all approved packaging types.
  2. Packaging Identification Code – 3 for Jerrycan.
  3. Packaging Identification Code – H for HDPE (High Density PolyEthylene).
  4. Packaging Identification Code – 1 for non-removable head.
  5. Packing Group Level Equivalent – The transport of hazardous goods like higher concentrations of Hydrogen Peroxide requires Packing Group II, this marking must be either X (Packing Group I, II, II) or Y (Packing Group II, III).
  6. Specific Gravity – must be a minimum value of 1.2.
    NOTE: We recommend the value is higher than 1.6 for increased structural integrity.
  7. Hydrostatic Test Pressure – statutory minimum is 100kPa.
    NOTE: We recommend a minimum value of 160 for lower concentrations of EndoSan and 200 for EndoSan50 (50% peroxide) product.
  8. Year of Manufacture – Only new packaging should be used and the date of manufacture not more than 2 years from the date of filling.
  9. Location of Manufacture
  10. Certification Mark – Manufacturer dependant
The following is a summary of storage requirements that will help to preserve the potency of hydrogen peroxide:

  • Temperature: Store hydrogen peroxide away from heat sources, such as ovens, radiators, and direct sunlight. Higher temperatures can accelerate the decomposition process of hydrogen peroxide, resulting in it expiring prematurely. The ideal storage temperature for hydrogen peroxide is between 35°F to 65°F (2°C to 18°C).
  • Container: Hydrogen peroxide should be stored in a clean, dry, and opaque container that keeps it away from light, preventing it from reacting with UV light energy that can cause it to break down.
  • Location: Store hydrogen peroxide in a cool, dark, and well-ventilated place away from heat sources or any flammable materials. You should not store it in damp, hot, or humid areas since this can lead to contamination or speed up the expiration process.
  • Keep away from incompatible substances: You should store hydrogen peroxide away from incompatible substances such as metals, alkalis, acids, and other reactive chemicals that may promote its decomposition.

By following the above storage requirements, you can help protect the shelf life of hydrogen peroxide effectively. 


Can You Use Expired Hydrogen Peroxide?

No, Using expired hydrogen peroxide should be avoided as it may not be effective and therefore unsuitable for use for any disinfection purposes. Expired hydrogen peroxide cannot be relied on to disinfect or be effective.


Is Expired Hydrogen Peroxide Dangerous?

Using expired hydrogen peroxide is not recommended, especially if the degree of decomposition is unknown. Also using an expired product for disinfection purposes that requires a full strength, in date product, will be unlikely to meet expectations in the required results which in turn could present danger depending on the application.


How to Dispose of Expired Hydrogen Peroxide?

Expired hydrogen peroxide should be disposed of properly, depending on the concentration and quantity you may need to adhere to standards required for the disposal of hazardous waste local to you.

In the UK it is important to consider whether it may be classified as hazardous waste. Waste is generally considered hazardous if it (or the material or substances it contains) are harmful to humans or the environment. If your expired hydrogen peroxide falls under this category, you must make sure that it is disposed of in a way that causes no harm or damage. You have responsibilities known as your ‘duty of care’.

You can find out if your local council offers a service to help you get rid of hazardous waste like chemicals and batteries by visiting the GOV.UK website. Alternatively, you can also contact a private hazardous waste management company, to safely deal with your waste. It is important to take the appropriate precautions when disposing of hazardous waste to ensure the safety of both people and the environment.


Does Hydrogen Peroxide Freeze?

Hydrogen peroxide can freeze at temperatures below 32°F (0°C). However, it is important to note that frozen hydrogen peroxide may not be safe to use, even if it appears to thaw out normally. Thawed hydrogen peroxide should be tested for potency before it is used to ensure that it is still effective.


Does Hydrogen Peroxide Evaporate?

Hydrogen peroxide is a volatile liquid that can evaporate over time. However, the evaporation rate is relatively low compared to other liquids. The concentration and storage conditions of hydrogen peroxide can also affect its evaporation rate.


About the Author

Mike Morrison is the EndoSan UK Product Manager, an experienced professional with over two decades of expertise in the water and hygiene industry. With a strong background in sales and operations, Mike has successfully navigated the challenges of various roles, enabling him to acquire comprehensive knowledge and experience in delivering exceptional results.

Mike’s deep understanding of the EndoSan product, coupled with his extensive network and customer-centric approach, positions him as a leading expert in the field.

With his wide knowledge in water and hygiene services, Mike is committed to sharing valuable insights and expert advice through EndoSan articles. By consistently delivering high-quality content, Mike aims to educate and inform readers on the benefits and applications of EndoSan Stabilised Hydrogen Peroxide, as well as other pertinent topics within the industry.


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