Synthesis of zeolitic material having aft framework structure and scr catalysts comprising the same

A process for preparing an aluminosilicate zeolite having AFT framework structure, which includes

• (1) providing a synthesis mixture comprising
• (A) a source for Al2O3,
• (B) a source for SiO2,
• (C1) a source for first organic structure directing agent comprising a N,N,N,N′,N′,N′-hexaethyl alkylenediammonium cation wherein the alkylene moiety is substituted or unsubstituted straight chain or branched chain, and
• (C2) a source for second organic structure directing agent comprising a cation selected from the group consisting of
• (C2-i) quaternary ammonium cations represented by formula (I),
• wherein
• R1, R2 and R3, independently from each other, are C1-C8 alkyl, and
• R4 is selected from C1-C8 alkyl, C3-C10 cycloalkyl, C6-C10 aryl and C7-C20 arylalkyl, each being optionally substituted by one or more hydroxyl groups;
• and
• (C2-ii) piperidinium cations represented by formula (II),
• wherein
• Ra and Rb, independently from each other, are selected from C1-C8 alkyl and C3-C10 cycloalkyl, or together with the N to which they are bound form a 5 or 6 membered saturated or unsaturated ring and
• Rc, Rd, Re, Rf and Rg independently from each other, are H, hydroxyl or C1-C8 alkyl;
• or
• wherein
• Ra and Re are linked together to form a C1-C3 linkage, for example ethylene linkage,
• Rb is C1-C8 alkyl, and
• Rc, Rd, Rf and Rg independently from each other, are H, hydroxyl or C1-C8 alkyl;
• and
• (C2-iii) pyrrolidinium cations represented by formula (III),
• wherein
• Ro and Rp, independently from each other, are C1-C5 alkyl or C3-C10 cycloalkyl, and
• Rq, Rr, Rs and Rt independently from each other, are H, hydroxyl or C1-C8 alkyl;
• (2) subjecting the synthesis mixture to crystallization conditions to form an AFT zeolite.