Mechanism of pyridine bases prepared from acrolein and ammonia by in situ infrared spectroscopy

• The in situ infrared spectroscopy of acrolein condensing with ammonia.
• The adsorption of acrolein on catalyst during condensation process of acrolein and ammonia.
• The reaction intermediate of propylene imine was investigated.
• The reaction order and active energy of acrolein and ammonia was calculated.
• The synthesis mechanism of pyridine and 3-picoline was proposed.

The in situ infrared spectroscopy of acrolein and ammonia over HF/MgZSM-5 was investigated to check the adsorption reaction of acrolein and ammonia. It was proved that propylene imine intermediate came up during the condensation process of adsorbed acrolein with ammonia. The strong adsorption of CO helps the formation of propylene imine. The reaction order and active energy were calculated according to the intensity of acrolein infrared spectroscopy. The synthesis of 3-picoline is likely to go through a flat adsorption of propylene imine and a deamination of amino dihydropyridine.

The synthesis of 3-picoline from acrolein and ammonia was considered to come from condensation of two propylene imine intermediate. The production of 3-picoline probably came from weak and flat adsorption of trans-propylene imine after the deamination reaction of dihydropyridine.Figure optionsDownload high-quality image (68 K)Download as PowerPoint slide