Description
Magnesium perchlorate is a powerful oxidizing agent, with the formula Mg(ClO4)2. Magnesium perchlorate decomposes at 250°C. The heat of formation is 568.90 kJ/mol. If water is added to magnesium perchlorate, the reaction is highly exothermic and may cause damage to the eyes. Thus, this salt should be added to a sufficient amount of water in order to form a dilute solution.
Mg(ClO4)2·6H2O is composed of white, deliquescent crystals which are soluble in water and alcohol but explosive when in contact with reducing materials. This compound is used as a drying agent for gases. This salt is highly exothermic when added to water and releases steamy HCl gas. It can be dried to form the anhydrate by heating to 250°C under vacuum. The hexahydrate losses two molecules of water at 244°C in air and further decomposes to the dihydrate at 336°C and the anhydrate at 438°C.
The anhydrate has been used as a desiccant to dry gas streams or air samples. However, it is no longer used since perchlorates tend to form explosive compounds with a variety of organic materials as well as other substances.
Chemical Properties
Magnesium perchlorate is a white, granular, or flaky powder that is highly deliquescent. It has a density of 2.21 g/cm³ and decomposes at 251°C. It is highly soluble in water (99.3 g per 100 mL at 18°C) and is also soluble in ethanol (24 g per 100 mL at 25°C). Its hexahydrate form consists of white rhombohedral crystals with a refractive index of 1.482 and a density of 1.98 g/cm³. It melts at approximately 185°C and is also highly soluble in water, a process accompanied by the release of heat.
Uses
Magnesium perchlorate is commonly utilized as a potent oxidizing agent. It is used as dehydrating agent in organic synthesis. It is practiced in many domains like pharma industry, pyrotechnics industry,in rechargeable batteries and it is a versatile tool in organic synthesis. It possesses photoelectronic and optical properties. Thus it can be used in photo electronic and optoelectronic devices. It is applied as a strong drying agent for gases.
Preparation
Magnesium perchlorate can be prepared by reacting magnesium carbonate with
a solution of perchloric acid:
MgCO3＋ HClO4→Mg(ClO4)2＋ CO2
This salt can also be prepared by an electrochemical
method in water whereby magnesium perchlorate is formed from magnesium chlorate in which a platinum anode and a rotating stainless steel cathode are employed.
Definition
ChEBI: Magnesium perchlorate is an alkaline earth salt. It contains a perchlorate. As a drying agent for gases. The article of commerce may contain an amount of water equivalent to a dihydrate, but even the trihydrate is said to be effective for drying gases.
Reactions
Magnesium perchlorate is a strong oxidizing agent. In aqueous solutions and in acid medium the most conspicuous reactions are those involving oxidation— characteristic of the oxidizing action of perchlorate ion, ClO4¯.
Thermal decomposition in the presence of a catalyst, such as manganese dioxide, yields magnesium chloride and oxygen: Mg (ClO4)2→MgCl2 + 4O2
General Description
A white crystalline solid. Strongly absorbs water from air and dissolves in it. Accordingly, used as a regenerable drying agent. May explode under prolonged exposure to heat or fire.
Reactivity Profile
Magnesium perchlorate is a strong oxidizing agent. Decomposes at 185-190°C [Hawley]. Noncombustible but accelerates the burning of combustible materials. If large quantities are involved in the fire or the combustible material is finely divided an explosion may result. Avoid contact with mineral acids because of the danger of explosion. In the preparation of anhydrous dimethyl sulfoxide by vacuum distillation from anhydrous Magnesium perchlorate, an explosion occurred [MCA Case History 1187, 1966]. Drying ethylene oxide with Magnesium perchlorate resulted in an explosion [NSC Newsletter. Chem. Soc. 1959]. Magnesium perchlorate used in drying hydrocarbons exploded when heated to 220°C [Ind. & Eng. News 17:70. 1939]. As soon as trimethyl phosphite contacted a small amount of Magnesium perchlorate in a flask, there was a flash and an explosion that shattered the flask [Allison 1968].
Hazard
Dangerous fire and explosion risk in contact
with organic materials.
Health Hazard
Inhalation of dust irritates mucous membranes. Ingestion of large amounts may be fatal; immediate symptoms include adominal pains, nausea and vomiting, diarrhea, pallor, blueness, shortness of breath, unconsciousness. Contact with eyes or skin causes irritation.
Fire Hazard
Behavior in Fire: Can form explosive mixture with combustible material or finely powdered metals. Increases the intensity of fires.
reaction suitability
reagent type: oxidant
Safety Profile
Moderately toxic by intraperitoneal route. Severe slun and eye irritant. A powerful oxidner which has caused many explosions in industry. Potentially explosive reactions with alkenes (above 22OoC), ammonia, aryl hydrazine + ether, dimethyl sulfoxide + heat, ethylene oxide, fluorobutane + water, organic materials, phosphorus, trimethyl phosphate. Reacts to form explosive products with ethanol (forms ethyl perchlorate), cellulose + dinitrogen tetraoxide + oxygen (forms cellulose nitrate). Avoid contact with mineral acids, but$ fluorides, hydrocarbons. A drying agent. When heated to decomposition it emits toxic fumes of MgO and Cl-. See also MAGNESIUM COMPOUNDS and PERCHLORATES
First aid
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Note to physician: Treat for methemoglobinemia.Spectrophotometry may be required for precise determination of levels of methemoglobin in urine.
storage
Color Code—Yellow: Reactive Hazard; Store in alocation separate from other materials, especially flammables and combustibles. Prior to working with this chemical you should be trained on its proper handling andstorage. Magnesium perchlorate must be stored to avoidcontact with fuels, finely powdered metals, mineral acids,ammonia, ethylene oxide, phosphorus, dimethyl sulfoxide,and trimethyl phosphite, since violent reactions occur.Shock may cause magnesium perchlorate to explode. Storein tightly closed containers in a cool, well-ventilated areaaway from flammable and combustible materials. Do notstore on wood floors. See OSHA Standard 1910.104 andNFPA 43A Code for the Storage of Liquid and SolidOxidizers for detailed handling and storage regulations.
Shipping
UN1475 Magnesium perchlorate, Hazard Class:
5.1; Labels: 5.1-Oxidizer.
Purification Methods
Magnesium perchlorate (Anhydrone, Dehydrite) [10034-81-8 (anhydrous)] M 259.2, m >250o, pK2 5
Incompatibilities
A powerful oxidizer. Violent reaction
with reducing agents; alkenes (above 220C), ammonia
gas; organic matter; ethylene oxide, finely divided or powdered metals, combustible materials, phosphorus, dimethylsulfoxide, mineral acids; wet argon; hydrazines, alcohols,
wet fluorobutane; butyl fluorides; organic materials. Forms
explosive material with ethyl alcohol. Incompatible with
many materials. Shock or heat may cause magnesium
perchlorate to explode.
