The synthesis of SAPO-34 and CoSAPO-34 from a triethylamine–hydrofluoric acid–water system

The synthesis of the highly selective methanol-to-olefin catalysts SAPO-34 and CoSAPO-34, using a unique combination of triethylamine templating agent and fluoride ion mineralizer, is reported. The control of both the Si/Al/P ratio and template content of the reaction gel mixture allows the formation of the other SAPO-based zeolitic systems. The fluoride ion mineralizer causes a reduction in nucleation time and an increase in crystallinity of SAPO-34. The structure-directing effects of the triethylamine template are discussed and shown to predominate through steric influences, rather than electronic effects. This was confirmed by quantitative thermogravimetric analysis and molecular-graphics techniques.