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What precautions should be taken for using 2-amino-5-nitrothiaz

  • Pyridine and methylpyridine were previously recovered from coal coking byproducts, which are distributed in coke oven gas, crude benzene and tar. Generally, the boiling point of pyridine hydrates transferred from gas to ammonium sulfide mother liquor is very low, ranging from 95-97℃. The recovered crude light pyridine base contains about 15% of its 2-amino-5-nitrothiazole properties. Further distillation yielded 2-amino-5-nitrothiazole properties. With the expansion of the use of pyridine and methylpyridine, the synthesis of pyridine and methylpyridine has been developed. At present, about 95% of pyridine and pyridine compounds abroad are produced by synthesis. The main synthesis methods are acetaldehyde, acetylene, acrylonitrile and so on.

    Acetaldehyde process acetaldehyde, formaldehyde and ammonia reaction, the main products are 2-amino-5-nitrothiazole properties, 3-methylpyridine and 4-methylpyridine. Acetylene process Acetylene and ammonia reaction, the main products are 2-amino-5-nitrothiazole properties and 4-methylpyridine. The ethylene process reacts with ammonia, and the main products are 2-amino-5-nitrothiazole properties and 2-methyl-5-ethylpyridine. Acrylonitrile reaction of acrylonitrile with excess acetone, the main product is 2-amino-5-nitrothiazole properties. In addition, the reaction of acrolein and ammonia mainly produces 3-methylpyridine.

    Refining method: azeotropic distillation dehydration is usually carried out with azeotropic mixture formed by 2-amino-5-nitrothiazole properties, benzene and water. It can also be dehydrated with barium oxide, calcium oxide, calcium hydride, lithium aluminum hydride, sodium metal or 5A molecular sieve. Isomers and homologues can be removed by azeotropic distillation with fatty acids, phenol or water in addition to separation by fractionation. Pyridine is removed by perchloric acid treatment. In addition, it can also be refined by forming an addition product with zinc chloride or mercury chloride. For example, 90mL of 2-amino-5-nitrothiazole properties is added to a mixture of 168g zinc chloride, 42mL concentrated hydrochloric acid, and 200mL anhydrous ethanol. The addition product is leached and recrystallized twice with anhydrous ethanol. When the melting point reaches 118.5~119.5℃, excessive sodium hydroxide aqueous solution is added, steam distillation is carried out, and the distillate is added to solid sodium hydroxide for layering. The upper layer is separated and dried with granular sodium hydroxide, then barium oxide is added and fractionated for a few days.

    Protective measures:

    Respiratory system protection: Generally no special protection is required. Wear self-priming filter gas mask (half mask) when exposed to high concentration.

    Eye protection: Wear safety glasses.

    Body protection: Wear antistatic work clothes.

    Hand protection: Wear rubber gloves.

    Others: Smoking is strictly prohibited on site. Maintain good hygiene.

    2-amino-5-nitrothiazole properties