Sodium bromide is a white crystalline or powder. Salty or bitter microstrip. Absorb moisture from the air, but not agglomerated deliquescence. Soluble in water. Low toxicity, irritation. For the determination of trace cadmium in analytical chemistry, photogravure, pharmaceuticals. Physical and chemical properties of colorless cubic crystals or white granular powder. Odorless, alkali and bitter. The relative density of 3.203 (25 ℃). Melting point 747 ℃. Hygroscopic in the air. Soluble in water (solubility 100 ℃ when 121g/100ml water) solution was neutral. Slightly soluble in alcohol. 51 ℃ when anhydrous sodium bromide solution precipitated crystals below 51 ℃ generated dihydrate. The bromide ion can be replaced by chlorine.
For photographic film, medical (sedatives), pesticides, perfumes, dyes and other industrial.
This product is mainly preparation method:
① direct role in the generation of iron and bromine bromide and sodium carbonate, ferrous and then get azeotropic. Byproducts are basic ferrous carbonate, ferrous and after boiling becomes high colloidal iron compounds, filtering slow. To avoid this drawback, preferably two bromine was added, the resulting primarily iron oxides, and thus the filter is very easy to wash, and the reaction is as follows:
Fe + Br2 → FeBr2
FeBr2 + Br2 → FeBr2 · FeBr3
FeBr2 · FeBr3 + Na2CO3 → NaBr + FeO · Fe2O3 + CO2
② a slight excess of bromine to direct the hot solution was added saturated sodium bicarbonate, to form a mixture of bromide and bromate:
3Br2 +6 NaOH = 5NaBr + NaBrO3 +3 H2O
At this time the mixture was evaporated to dryness, the solid residue obtained mixture was heated with carbon, the reduction of bromate bromide:
NaBrO3 +3 C = NaBr +3 CO ↑
Finally, dissolved in water, then filtered crystallization, drying at 110-130 ° C to obtain.
This method is a general method for preparing bromide bromine, general industrial use.