He Sodium peroxide Is a chemical compound of formula Na 2 OR 2 Which has two ionic bonds between the two sodium atoms and the O 2 molecule.
Sodium peroxide exists in various hydrates and peroxyhydrates including Na 2 OR 2 2H 2 OR 2 · 4H 2 O na 2 OR 2 2H 2 O na 2 OR 2 2H 2 OR 2 And Na 2 OR 2 · 8H 2 O. It has a hexagonal crystalline structure, however when heated, this form undergoes a transition to a phase of unknown symmetry at 512 ° C.
Figure 1: Structure of sodium peroxide.
Its crystalline structure is presented in figure 2 (Sodium: sodium peroxide, 1993-2016).
Figure 2: Crystalline structure of sodium peroxide.
Sodium peroxide can be prepared on a large scale by the reaction of sodium metal with oxygen at 130-200 ° C (Ashford, 1994), a process that generates sodium oxide, which in a separate step absorbs oxygen:
4 Na + O 2 → Na 2 OR
2 Na 2 O + O 2 → 2 Na 2 OR 2
The present discontinuous procedure involves the oxidation of sodium in sodium monoxide with dry air and subsequent oxidation of the peroxide monoxide with 90% oxygen.
In 1951, USI began to operate the first continuous process for the production of sodium peroxide. The process is unique in one respect: it uses air instead of pure oxygen. For almost 70 years, variations of a batch process have been used (SCHOW, 1957), for example, the commercial product contains between 90 and 95% hydrogen peroxide.
Physical and chemical properties of sodium peroxide
Sodium peroxide is a yellowish granular solid that turns yellow in contact with the atmosphere (National Center for Biotechnology Information, S.F.). Their appearance is illustrated in Figure 3.
Figure 3: appearance of sodium peroxide.
Sodium peroxide has a molecular weight of 77.98 g / mol and a density of 2.805 g / ml. The compound has a melting point of 460.00 ° C where it begins to decompose to sodium oxide and molecular oxygen according to the reaction:
2 Na 2 O 2 → 2 Na 2 O + O 2
Its boiling point is 657 ° C (Royal Society of Chemistry, 2015).
Sodium peroxide reacts violently with reducing agents, combustible materials and light metals. Reacts exotherm and rapidly or even explosively with water to form a strong base (NaOH) and oxygen (O2).
A mixture with ammonium persulfate can explode if subjected to friction (grinding in a mortar), if it is heated, or if a stream of gaseous carbon dioxide is passed over it.
Reacts very vigorously with hydrogen sulphide gas. Even in the absence of air, the reaction may be accompanied by flame. An explosion occurs when gaseous carbon dioxide is passed over a mixture of sodium peroxide and magnesium powder.
Mixtures with acetic acid or acetic anhydride can explode if they are not kept cold. They are spontaneously flammable on contact with aniline, benzene, diethyl ether or organic materials such as paper and wood.
Mixtures with charcoal, glycerin, certain oils and phosphorus burn or explode. A mixture with calcium carbide (powder) can burst into flames when exposed to moist air and explode when heated.
It decomposes, often violently in the presence of catalytic amounts of manganese dioxide. Mixing with sulfur monochloride leads to a violent reaction. It can react and ignite the fuels (Sodium Peroxide, 2016).
Reactivity and hazards
Sodium peroxide is a compound classified as strong base, explosive and strong oxidizing agent according to its reactivity alert. Blends with combustible material are easily ignited by friction, heat or contact with moisture. It can decompose vigorously under prolonged exposure to heat, causing the rupture of the containers that contain it.
Very hazardous in case of contact with skin and eyes (irritant) and in cases of ingestion and inhalation. Prolonged exposure may cause skin burns and ulcerations. Overexposure by inhalation may cause respiratory irritation.
Inflammation of the eye is characterized by redness, watering and itching. Inflammation of the skin is characterized by itching, peeling, redness or, occasionally, blistering.
In case of visual contact, contact lenses should be checked and removed. Immediately flush eyes with running water for at least 15 minutes, keeping eyelids open.
In case of contact with skin, gently and thoroughly wash contaminated skin with running water and non-abrasive soap. Cold water can be used. Irritated skin should be covered with an emollient.
If contact with the skin is severe, it should be washed with a disinfectant soap and cover the skin contaminated with an anti-bacterial cream.
In case of inhalation, the victim should be allowed to stand in a well-ventilated area.
Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a shirt collar, belt or tie. If breathing is difficult, give oxygen. If the victim is not breathing, perform a mouth-to-mouth resuscitation.
In case of ingestion, do not induce vomiting. If the victim is not breathing, perform a mouth-to-mouth resuscitation.
In all cases seek immediate medical attention (Material Safety Data Sheet Sodium peroxide, 2013).
Applications
Sodium peroxide is used in laundry bleaches, as it reacts with water to produce hydrogen peroxide, a bleaching agent according to the reaction:
Na 2 OR 2 + 2 H 2 O → 2 NaOH + H 2 OR 2
Besides of hydrogen peroxide , The reaction produces sodium hydroxide (bleach), which maintains the alkaline solution. Hot water and an alkaline solution are both necessary for hydrogen peroxide to function better as a bleach (Field, S.F.).
Sodium peroxide is used to bleach wood pulp for the production of paper and textiles. It is currently used mainly for specialized laboratory operations, eg mineral extraction. In addition, sodium peroxide is used as the oxidizing agent in chemical reactions.
It is also used as a source of oxygen by reacting it with carbon dioxide to produce oxygen and sodium carbonate, thus it is particularly useful in diving equipment, submarines, etc. (Using sodium peroxide to scrub carbon dioxide emissions, 2014).
References
- Ashford, R. (1994). Ashford's Dictionary of Industrial Chemicals. London: Publications Ltd.
- Field, S. (S.F.). Ingredients -Sodium peroxide. Retrieved from sci-toys.com.
- Material Safety Data Sheet Sodium peroxide. (2013, May 21). Retrieved from sciencelab.com.
- National Center for Biotechnology Information. (S.F.). PubChem Compound Database; CID = 14803. Retrieved from PubChem.
- Royal Society of Chemistry. (2015). Sodium peroxide. Retrieved from chemspider.com.
- SCHOW, H. R. (1957). The Sodium Peroxide Production Story. Advances in Chemistry, Vol. 19, 118-123.
- SODIUM PEROXIDE. (2016). Retrieved from cameochemicals.
- Sodium: sodium peroxide. (1993-2016). Retrieved from webelements.
- Using sodium peroxide to scrub carbon dioxide emissions. (2014, November 10). Retrieved from stackexchange.