1. By pyridine and ferric chloride reaction derived. Take 70g anhydrous pyridine mixed with 13g of anhydrous ferric chloride, the reaction tube was heated in a sealed tube at 300 ℃ for about 35h. After cooling, the reaction solidified to red and black crystals, open the sealed tube, washed with a small amount of hot water red and black solid solution. Extraction with ether removed the oily impurities. After neutralization with sodium bicarbonate, excess pyridine is removed by heating with steam. The mixture was then adjusted to a strong base and the 2,2'-bipyridine was distilled off with steam. After the steamed acidified evaporated and concentrated, plus sodium hydroxide, extracted with ether to remove the ether to give the crude product. The crude product is recrystallized from B and the activated carbon is decolorized to obtain pure product. In addition, the reaction of α-picoline [109-06-8] with potassium permanganate can also be obtained by purification.
2. Anhydrous pyridine and anhydrous ferric chloride mixed, heated reaction, cooling and solidified red and black crystals. Heat with steam to remove excess pyridine. 2,2'-bipyridine was distilled off. Plus sodium hydroxide as a solvent with ether, remove the ether, too crude. With iron-free activated carbon bleaching, filtration, have white leaf-shaped crystals, namely pure 2,2'-bipyridine.