PPt on h2o2 stabilizers

1. H2O2 Stabilizers -
Literature Review
Hydrogen peroxide stabilization using
chemical stabilisers

2. Jens
Martensson
Objective
•To find a stabiliser which will restrict the auto
decomposition of hydrogen peroxide without catalytic
poisoning.
•Due to slowing down of auto decomposition of hydrogen
peroxide will increase the selflife.
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Sweta
Ranjan
Tripathy

3. Jens
Martensson
Introduction
1. Catalytic Poisoning:- It refers to the partial and total deactivation of a catalyst by a chemical compound.
2. Stabilisers:- These are the chemical compounds that postpone the autocatalytic process or self-decomposition of the fuel or
components.
3. Stabilization:- To improve hydrogen peroxide storage stability so that there will be no or less decomposition. Based on the
encountered contaminates, storage duration as well as temperature during the period depicts the stabiliser to be used. As there is no
particular stabiliser for the inhibition of its decomposition the condition should be considered.
4. Stabilization effect:- Effectiveness depends on
1. Type and quantity of stabilizers
2. Initial concentration and purity of hydrogen peroxide
3. Material of container and its surface pre treatment
5. Stabilization requirements:- The use or requirement of stabiliser is limited due to the poisoning effect of stabiliser on
catalyst. The effectiveness of stabilisers decreases due to the reaction with container material.
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Points discussed
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4. Jens
Martensson
Hydrogen Peroxide
• Hydrogen peroxide is a chemical compound with the formula H2O2.
• Very pale blue Liquid, slightly more viscous than water.
• Used as an oxidizer, bleaching agent, and antiseptic. Concentrated hydrogen peroxide, or "high-test
peroxide", is a reactive oxygen species and has been used as a propellant in rocketry.
• Its chemistry is dominated by the O-O bond. Hydrogen peroxide is the simplest peroxide (a
compound with an oxygen–oxygen single bond). It slowly decomposes in the presence of light.
• Hydrogen peroxide is typically stored with a stabilizer in a weakly acidic solution in a dark colored
bottle.
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Why Hydrogen peroxide is unstable
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5. Jens
Martensson
Hydrogen Peroxide
• In peroxide oxygen has an oxidation state of -1 but as we know that oxygen is stable at its oxidation state of -2
this is due to its affinity towards electrons for reduction to -2 oxidation state the peroxide molecules are unstable
and reactive.. So, according to Fajjan's rule, greater the oxidation state, more will be the polarizing power and
hence more covalent is the bond.
• Also, H2O involves H-bonding.
• The peroxide bond, or the bond between the two oxygen atoms, breaks very easily to form two oxygen radicals.
Radicals are highly reactive and can be very dangerous. This is why the body needs to have special enzymes to
remove free radicals when they form, such as superoxide dismutase.
• This high reactivity is why hydrogen peroxide can only be sold at low concentrations in stores. At high
concentrations it can become explosive as the molecule decomposes. Furthermore, it is typically sold in a dark
bottle because that decomposition can be promoted by light.
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Structure and properties
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6. Jens
Martensson
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Paper review
• The decomposition rate increases exponentially at higher temperature.
• Decomposition rate of 0.0010% at 50oC but due to the presence of stabilizers( sodium
stannate and 8-hydroxyquinoline pyrophosphate) the rate decreases to 0.0003% at 50oC
at 90% concentration.
• Stabilization depends on the catalytic ions(Fe3+ Cu2+, Cr2+),nature(rough or presence of
cracks) and material of the wall(Polyethylene bottles are more prefered than paffined
walled glassed bottles) .
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7. Jens
Martensson
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Determination of stability
• The determination of stability includes two methods
1. Direct method
• This method includes titration of the sample by a standard acid solution of potassium permanganate.
This method shows satisfactory results for long term storage where decomposition is very slow.
2. Gas evolution method
• In this method the amount of oxygen evolved for a particular time interval in a specified temperature
range will depicts the decomposition rate of the peroxide sample.
•
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8. Jens
Martensson
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Direct Method
• The simplest method for determining the decomposition rate is by titrating the sample by a standard acid of potassium
permanganate.
• For finding the decomposition rate we have to find the initial concentration and final concentration(after the measured
time interval)
• It shows satisfactory results for long term storage as well as in tests where large changes occur in hydrogen peroxide.
• For precise data points to be noted
• Temperature variation
• Loss of hydrogen peroxide and loss of water due to evaporation.
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9. Jens
Martensson
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Gas Evolution Method
• Gas evolution method includes the measuring the evolution oxygen whose rate of evolution will depicts the
rate of decomposition according to the following equation.
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10. Jens
Martensson
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Tripathy
Gas Evolution method setup

11. Jens
Martensson
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Tripathy
Effect on stability of surface to volume ratio and nature of the surface
•Surface to Volume ratio
• Decomposition rate is proportional to surface to volume ratio

12. Jens
Martensson
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Ranjan
Tripathy
Effect on stability of surface to volume ratio and nature of the surface
Hydrogen peroxide is highly sensitive towards the material of the container wall
•Pyrex glass is suitable for storage after cleansing it with nitric acid.
•Aluminum(due to anodizing effect), manganese alloys or stainless steel can
used for storage.
•But polyethylene materials are more preferred than any other material for
storage.
•Common soda glass is not recommended for H2O2, as soda will increase the pH
to basic.

13. Jens
Martensson
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Ranjan
Tripathy
Stability of Hydrogen peroxide
•Due to addition of H+ ion there is a decrease in decomposition rate in a homogenous uncatalysed
reaction.(according to following equation)
•Presence of OH- ion will also decrease the stability of solution.
•The addition of stabilisers nullifies the catalytic activities.

14. Jens
Martensson
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Sweta
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Effect of catalytic impurities
•From table1 we can conclude some metal shows a catalytic effect on concentrated hydrogen peroxide.
•Metals are less active catalyst but there oxides shows(e.g. Copper) shows appreciable effect on peroxide.
•Some metals like Al,Sn,Zn and Cd show less effect comparatively where as AgO, MnO2 , PbO, and Pb304
react intensely with peroxide.

15. Jens
Martensson
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Sweta
Ranjan
Tripathy
Effect of catalytic impurities
•Presence of single metal act as catalyst but some pair of mixture of these metallic catalyst increase the
decomposition rate(Fig 5)
•The Fe and Cu pair shows maximum effect than Fe and Ag
•Presence of mercury as well Iodine or Iodic acid also shows effect on peroxide

16. Jens
Martensson
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Sweta
Ranjan
Tripathy
Stabilizing Agent
•Principle of Stabilization
• Inorganic chemicals like sodium stannate or 8-hydroxyquinoline can be used as stabilizers rather than organic
stabilizers for long term storage.
• Organic substances in general are subject to a slow oxidation at ordinary temperatures by hydrogen peroxide.
• The colloidal stannic oxide accepts the catalytic metal ions and brings the dispersed metallic impurities.
• Due to the presence of oxine the effect of Fe+++(small concentration) is less.
• Sodium pyrophosphate has a noticeable effect on large concentrations of Fe3+ ion but not on the copper compound.
• Hydrolysis of sodium stannate leads to formation of hydrous stannic oxide absorption of ferric hydroxide ion well as
on cuporous ion.

17. Jens
Martensson
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Sweta
Ranjan
Tripathy
Stabilizing Agent
•Principle of Stabilization
• Inorganic chemicals like sodium stannate or 8-hydroxyquinoline can be used as stabilizers rather than organic stabilizers for long term
storage.
• Organic substances in general are subject to a slow oxidation at ordinary temperatures by hydrogen peroxide.
• The colloidal stannic oxide accepts the catalytic metal ions and brings the dispersed metallic impurities.
• Due to the presence of oxine the effect of Fe+++(small concentration) is less.
• Sodium pyrophosphate has a noticeable effect on large concentrations of Fe3+ ion but not on the copper compound.
• Hydrolysis of sodium stannate leads to formation of hydrous stannic oxide absorption of ferric hydroxide ion well as on
cuporous ion.

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Martensson
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Tripathy
Stabilizing Agent
•The maximum effect of stabilizers is shown to a certain concentration of stabilizers as in Stannate
(following table 3)

19. Jens
Martensson
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Tripathy
Choice Of Stabilizers
•The type of stabilizers chosen according to
• Period of storage:- 5 years
• Temperatures it prevailing:- 25oC to 30oC
• Condition ultimately at which the hydrogen peroxide will be used:- Liquid
• Sodium stannate and Sodium pyrophosphate can be used as stabiliser.

20. Jens
Martensson
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Sweta
Ranjan
Tripathy
Mechanism of Stabilization of hydrogen peroxide using stannate as stabiliser
•Addition of stabilisers decreases the decomposition reaction of H2O2, as stabilizers deactivates the catalytic ions .
•Stabilizers are effective as colloids
•Increase in viscosity and surface tension due to presence of gelatine, starch or glue may restraint the effect of these additives.
•They represses the following reaction which further decreases the decomposition.
Sln
o.
Stabilizer Mechanism
1 Sodium
stannate

21. Jens
Martensson
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Sweta
Ranjan
Tripathy
Effect of pH on Decomposition
•pH is controlled by addition of sulphuric acid and sodium hydroxide, purity of acid and base should
be very high.
•At lower concentration along with at lower pH the decomposition is rate is higher at 50oC
• At fixed pH, concentrated solution is more stable than diluted H2O2.

22. Jens
Martensson
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Sweta
Ranjan
Tripathy
Effect of pH on Decomposition
•The rapid decrease in decomposition rate at higher pH(4.0 to 5.0) is due to the coagulation of the metallic colloid
that was occurring,there is a resultant sharp decline in the surface area of the hydrous oxide (metallic
catalyst)exposed to the solution.

23. Jens
Martensson
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Sweta
Ranjan
Tripathy
Effect of pH on Decomposition
•The following diagrams shows the variation of decomposition rate in the presence of Fe(fig 9) at certain pH and at a pH range
of 5 to 7

24. Jens
Martensson
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Sweta
Ranjan
Tripathy
Effect of pH on Decomposition
•The following diagrams shows the effect on decomposition rate in the presence of Fe at different
pH(Fig 10)

25. Jens
Martensson
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Sweta
Ranjan
Tripathy
Deactivation of Catalyst
•According to [3] is has been found that after 20 startup and shutdown cycle the activity of the catalyst bed decreases.
•It has been found that in 25th cycle there is a significant rise in ignition delay and decrease in steady chamber pressure as well
as steady catalytic bed temperature.
•The duration of each cycle is for 1s.
•According to the reference [3] it has been found that the the catalyst gets deactivated or the performance of the catalyst get
lowered due to following reasons:-
• Oxidation of the dispersed phase
• Attrition action of hot gases
• Catalytic poisoning by Sn

26. Jens
Martensson
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Sweta
Ranjan
Tripathy
Why hydrogen peroxide is unstable at lower pH
•Concentrated acids, have the ability to protonate the hydrogen peroxide.
• Then protonated hydrogen peroxide can then loose a water molecule either in an SN2 type mechanism with rear-side
attack on the other oxygen or in an SN1 type mechanism to create a hydroxyl cation
HO-OH + H+ --->HO-OH2
+
•In the rear-attack version,i.e. in SN2 this would directly void the attacking atom of two electrons formally.
• The cation would probably jump to anything that is not oxygen and has electrons to share in SN1.
• hydrogen peroxide is stabilised by interactions of the free p-orbital of one oxygen and the σ∗(OH) orbital on the other
oxygen
•When protonated, the proton will likely be added to the p-type lone pair rather than to the sp-hybrid type lone pair,
inhibiting this stabilising interaction and further decreasing the strength of the O−O bond.

27. Jens
Martensson
Reduction of decomposition rate vs. Sn/Fe ratio
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Sweta
Ranjan
Tripathy

28. Refrences
1.https://patents.google.com/patent/US1995063
2.Hydrogen peroxide by W. C. Schumb,C, N. Satterfield,R. L, Wentworth
3.Performance and deactivation of Ir/g-Al2O3 catalyst in thehydrogen peroxide
monopropellant thruster,Hanjing Tian, Tao Zhang, Xiaoying Sun, Dongbai Liang, Liwu Lin

29. Thank
You
Sweta Ranjan
Tripathy
srtripathy0513@gmail.com