Magnesiumhydroxid Chemische Eigenschaften,Einsatz,Produktion Methoden
R-Sätze Betriebsanweisung:
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
S-Sätze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.
S37/39:Bei der Arbeit geeignete Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
Beschreibung
A white, bulky powder. It dissolves in dilute acids, but is practically insoluble in water and in alcohol.
Chemische Eigenschaften
Magnesium hydroxide, Mg(OHn, also known as magnesium hydrate and brucite, is a white powder that is very slightly soluble in water. It decomposes at 350°C (662 OF). It is used in the extraction of magnesium metal and as a reagent in the sulfite wood pulp process. Magnesium hydroxide is formed by the reaction of sodium hydroxide and a soluble magnesium salt solution. Brucite, a mineral composed of magnesium hydroxide with occasional traces of iron and manganese, is a white to grayish translucent secondary mineral found with serpentine and metamorphic dolomites.
Physikalische Eigenschaften
Magnesium Hydroxide decomposes when heated to 360°C and forms
the oxide, MgO. It is very slightly soluble in water at
0.00122 g/100 ml and has a solubility product of
5.61×10
-12. Crystals of Mg(OH)2 have a refractive
index of 1.559. Its heat of formation is –925 kJ/mol
with an entropy of 63 J/mol·K.
As a suspension in water, it is often called milk of
magnesia because of its milk-like appearance. The solid
mineral form of magnesium hydroxide is known as
“brucite”.
It can be prepared by the metathesis reaction
between any soluble magnesium salts and an alkali
hydroxide such as sodium or even ammonium:
Mg
2+(aq)＋2OH
-(aq)→Mg(OH)2(solid)
Magnesium hydroxide is a common component of
antacids and laxatives. It interferes with the absorption
of folic acid and iron. Its low solubility makes it a weak base.
Another method of commercial manufacture of
magnesium hydroxide involves the chloride obtained from seawater. After the chloride is recrystallized
several times to obtain a level of purity, it is calcined at
about 1000°C:
MgCl2·6H2O → MgCl2＋6H2O
→ Mg(OH)
-xCl2
-x＋xHCl
→ MgO＋(2－x)HCl
Occurrence
Magnesium Hydroxide occurs naturally as the mineral brucite. Brucite, usually found as a low temperature, hydrothermal vein mineral associated with calcite, aragonite, talc, or magnesite, appears as a decomposition product of magnesium silicates associated with serpentine, dolomite, magnesite, and chromite. Brucite also occurs as a hydrated form of periclase, and is found in serpentine, marble, chlorite schists, and in crystalline limestone.
Verwenden
Magnesium Hydroxide is an alkali that is a general purpose food
additive. it exists as a white powder and has poor solubility in water
and in alcohol. in frozen desserts it will increase the tendency for fat
globules to clump, which results in an increase in dryness. it reacts
with triglycerides in fatty acids to form soaps. it also functions as a
drying agent in foods.
Definition
ChEBI: A magnesium hydroxide in which the magnesium atom is bound to two hydroxide groups.
Pharmazeutische Anwendungen
The synthesis of magnesium hydroxide [Mg(OH)
2]
is based on a metathesis reaction in which magnesium salts are reacted with sodium or potassium hydroxide.
Magnesium hydroxide (Mg(OH)
2) has only limited solubility
in water and the resulting suspension is called milk of magnesia, which is commonly used as an antacid and is
known to be a mild base.
Magnesium hydroxide [Mg(OH)
2] is present in antacids because of its laxative properties and is also the
main ingredient of the ‘milk of magnesia’. The ‘milk of magnesia’ is a suspension of Mg(OH)
2 in water,
which has a milk-like appearance because of the low aqueous solubility of Mg(OH)
2. It is considered as a
strong electrolyte and a weak base and is given to the patient for indigestion and heartburn. The alkaline
suspension neutralises any excess stomach acid and therefore works as an antacid. It also stimulates intestinal
movement, as the magnesium ions increases the water content in the intestines through its osmotic effect and
as a result softens any faeces present.
Sicherheitsprofil
Moderately toxic by
intraperitoneal route. Human systemic
effects: chlorine level changes, coma,
somnolence. Incompatible with maleic
anhydride, phosphorus. See also
MAGNESIUM COMPOUNDS.
Magnesiumhydroxid Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
