铬催化剂促进CH_4/NH_3等离子体C-N偶联反应合成HCN

Chromium catalyst promoted C-N coupling reaction in CH_4/NH_3 plasma for synthesis of hydrogen cyanide

氰化氢作为一种重要的基本化工原料,在合成医药和精细化学品等领域有广泛用途.为解决氰化氢生产技术多在1 000℃以上的高温进行,且使用贵金属Pt或Pt-Rh催化剂的问题,在介质阻挡放电等离子体和负载型Cr催化剂条件下,通过CH4/NH3偶联反应一步合成氰化氢和乙腈等高附加值化合物,并系统研究了负载型Cr催化剂的负载量和载体类型对甲烷转化率和产物选择性的影响.在最优条件下(20mL·min^(-1)甲烷、40mL·min^(-1)氨气、负载量10%Cr/S-1催化剂、380℃反应温度),甲烷转化率达到30%左右,氰化氢选择性达到80%左右.该等离子体催化CH_4/NH_3偶联反应为氰化氢和乙腈提供了一种绿色且廉价的合成方法,也为甲烷和氨气精细化利用开辟了新途径.

Hydrogen cyanide,an important basic chemical stock,has been widely used in the synthesis of medicine and fine chemicals.However,hydrogen cyanide is usually produced at more than 1 000℃,in which,the noble metal catalysts,i.e.,Pt or Pt-Rh alloy catalysts are employed necessarily.To solve this problem,using a dielectric barrier discharge plasma,CH 4/NH 3 coupling reaction can be promoted by Cr catalyst to synthesize hydrogen cyanide,with a by-product of acetonitrile.The effects of Cr loading and the support materials on the methane conversion and products selectivity are investigated.Under the optimized conditions(20 mL·min-1 CH 4,40 mL·min-1 NH 3,10%Cr/S-1 catalyst,380℃),30%methane conversion is obtained,along with 80%hydrogen cyanide selectivity.These experimental results indicate that the plasma-catalytic CH 4/NH 3 coupling reaction is a potential technology to provide a green and cheap method for the synthesis of hydrogen cyanide and acetonitrile,and to open a new way for fine application of CH 4 and NH 3.