气相法合成2-甲基-5-乙基-吡啶

Preparation of 2-methyl-5-ethyl-pyridine with vapor-phase way

以γ-Al2O3为催化剂、三聚乙醛和氨气为原料，气-固催化法合成了2-甲基-5-乙基-吡啶。考察了反应条件对三聚乙醛的转化率和产品收率的影响。合适的反应条件为：原料汽化温度高于150℃；反应温度控制在225～275℃；反应压力控制在0．3～0．6MPa；氨气用量为理论量的4．5倍；原料空速小于7×10^4s^-1。原料三聚乙醛的转化率可达到97％，产品2-甲基-5-乙基-吡啶的收率可达到70％。该法不仅原料成本比液相法低，而且更容易实现大规模工业连续化生产。

2-methyl-5-ethyl pyridine（MEP） is prepared from paraldehyde and ammonia gas using γ-Al2O3 as a catalyst. The factors which affect the conversion of material paraldehyde and the yield of product MEP are studied. The conversion of material paraldehyde can be 97% and the yield of product MEP be 70% with the temperature of vaporization tank above 150 ℃, 225 - 275℃ of the reaction temperature, 0.3 - 0.6 MPa of the reaction pressure, 4.5 times the theoretical quantity of ammonia amount, space velocity of material below 7×10^4s^-1. This method costs less and is much easier to be industrialized than the liquid phase one.