The lithium hydroxide is a chemical compound of formula LiOH (EMBL-EBI, 2008). Lithium hydroxide is an inorganic basic compound. It is used largely in organic synthesis to promote the reaction due to its strong basicity.
Lithium hydroxide is not freely found in nature. It is very reactive and if it were in nature it could easily react to form other compounds. However, some lithium / aluminum hydroxides that form various mixtures can be found in various minerals.
Figure 1: structure of lithium hydroxide.
In 1950, the Li-6 isotope was used as a raw material to produce thermonuclear weapons such as the hydrogen bomb.
From that moment the atomic energy industry in the United States began to use a large amount of lithium hydroxide leading to the surprising development of the lithium industry (Lithium hydroxide, 2016).
Most of lithium hydroxide is produced from the reaction between lithium carbonate and calcium hydroxide (Lythium hydroxide Formula, SF). This reaction produces lithium hydroxide and also calcium carbonate:
Li 2 CO 3 + Ca (OH) 2 → 2 LiOH + CaCO 3
It is also prepared from the reaction of lithium oxide and water:
Li 2 O + H 2 O → 2LiOH
Lithium hydroxide was used as carbon dioxide absorbers in the army's submarine and inflatable balloon fountain in 1944.
Physical and chemical properties
Lithium hydroxide are white crystals without a characteristic aroma (National Center for Biotechnology Information., 2017). Its appearance is shown in figure 2.
Figure 2: appearance of lithium hydroxide.
In aqueous solution it forms a crystalline liquid with a pungent aroma. Its molecular weight is 23.91 g / mol. It exists in two forms: the anhydrous and the monohydrate LiOH.H2O, which has a molecular weight of 41.96 g / mo. The compound has a density of 1.46 g / ml for the anhydrous form and 1.51 g / ml for the monohydrate form.
Its melting and boiling points are 462ºC and 924ºC respectively. Lithium hydroxide is the only alkaline hydroxide that does not present polymorphism, and its lattice has a tetragonal structure. The compound is very soluble in water and is slightly soluble in ethanol (Royal Society of Chemistry, 2015).
Lithium hydroxide and the other alkali hydroxides (NaOH, KOH, RbOH, and CsOH) are very versatile to use in organic synthesis because they are stronger bases that react easily.
It can react with water and carbon dioxide at room temperature. It can also react with many metals such as Ag, Au, Cu, and Pt, so it has been an important starting material in organometallic synthesis.
Lithium hydroxide solutions exothermically neutralize acids to form salts plus water. They react with certain metals (such as aluminum and zinc) to form oxides or hydroxides of the metal and generate hydrogen gas. They can initiate polymerization reactions in polymerizable organic compounds, especially epoxides.
It can generate flammable and / or toxic gases with ammonium salts, nitrides, halogenated organic compounds, various metals, peroxides and hydroperoxides. It can serve as a catalyst.
It reacts when heated above around 84 ° C with aqueous solutions of reducing sugars other than sucrose, to develop toxic levels of carbon monoxide (CAMEO, 2016).
Reactivity and hazards
Lithium hydroxide is a stable compound, although it is incompatible with strong acids, carbon dioxide, and moisture. The substance decomposes on heating (924 ° C), producing toxic fumes.
The solution in water is a strong base, reacts violently with acid, and is corrosive to aluminum and zinc. Reacts with oxidants.
The compound is corrosive to the eyes, the skin, the respiratory tract and if swallowed. Inhalation of the substance can cause pulmonary edema.
Symptoms of pulmonary edema often do not appear for a few hours and are aggravated by physical exertion. Exposure can cause death. Effects can be delayed (National Institute for Occupational Safety and Health, 2015).
If the compound comes into contact with the eyes, the contact lenses should be checked and removed. Eyes should be flushed immediately with plenty of water for at least 15 minutes with cold water.
In case of skin contact, the affected area should be rinsed immediately for at least 15 minutes with plenty of water or a weak acid, such as vinegar, while removing contaminated clothing and shoes.
Cover irritated skin with an emollient. Wash clothing and shoes before reuse. If the contact is severe, wash with a disinfectant soap and cover the contaminated skin with an antibacterial cream.
In case of inhalation, the victim should be moved to a cool place. If not breathing, artificial respiration is given. If breathing is difficult, give oxygen.
If the compound is ingested, vomiting should not be induced. Loosen tight clothing such as a shirt collar, belt, or tie.
In all cases, immediate medical attention should be obtained (Material Safety Data Sheet Lithium hydroxide, 21).
Applications
Lithium hydroxide is used in the manufacture of lithium salts (soaps) of stearic and other fatty acids.
These soaps are widely used as thickeners in lubricating greases to improve heat resistance, water resistance, stability, and mechanical properties. Grease additives can be used in car, plane and crane bearings etc.
Solid calcined lithium hydroxide can be used as a carbon dioxide absorber for crew members in spacecraft and submarine.
The spacecraft for NASA's Mercury, Geminni and Apollo projects used lithium hydroxide as absorbents. It has a reliable performance and can easily absorb carbon dioxide from water vapor. The chemical reaction is:
2LiOH + CO 2 → Li 2 CO 3 + H 2 O.
1g of anhydrous lithium hydroxide can absorb carbon dioxide with a volume of 450ml. Only 750 g of anhydrous lithium hydroxide can soak up the carbon dioxide exhaled by one person each day.
Lithium hydroxide and other lithium compounds have recently been used for the development and study of alkaline batteries (ENCYCLOPÆDIA BRITANNICA, 2013).
References
- CAMEO. (2016). LITHIUM HYDROXIDE, SOLUTION. Recovered from cameochemicals.
- EMBL-EBI. (2008, January 13). lithium hydroxide. Recovered from ChEBI.
- ENCYCLOPÆDIA BRITANNICA. (2013, August 23). Lithium (Li). Recovered from britannica.
- Lithium hydroxide. (2016). Recovered from chemicalbook.com.
- Lythium hydroxide Formula. (SF). Recovered from softschools.com.
- Material Safety Data Sheet Lithium hydroxide. (21, May 2013). Recovered from sciencelab.com.
- National Center for Biotechnology Information. (2017, April 30). PubChem Compound Database; CID = 3939. Retrieved from PubChem.
- National Institute for Occupational Safety and Health. (2015, July 22). LITHIUM HYDROXIDE. Recovered from cdc.gov.
- Royal Society of Chemistry. (2015). Lithium hydroxide. Recovered from chemspider: chemspider.com.