How small changes to methylated piperidinium cations impact the synthesis of zeolite SSZ ‐39

Abstract Here we report a synthesis study of SSZ‐39 with four different organic structure directing agents (OSDA). The goal was to determine how subtle changes to the OSDA architecture impact crystallization kinetics, material composition, and other properties. The most commonly used OSDA 3,5‐methyl‐ N,N ‐methyl piperidinium hydroxide (PIPPY) forms SSZ‐39 in approximately 24 h per literature reports, whereas 3,5‐methyl‐ N,N ‐ethyl piperidinium hydroxide forms SSZ‐13 in under 24 h. More interestingly, 2,6‐methyl‐ N,N ‐ethyl piperidinium hydroxide also crystallizes SSZ‐39 at rates comparable to PIPPY, albeit with a higher Si/Al ratio, whereas 2,6‐methyl‐ N,N ‐methyl piperidinium hydroxide forms SSZ‐39 but takes three to four days to complete crystallization. Experiments with mixtures of the two 2,6‐derivatives along with experiments with seed crystals strongly suggest that the methylated 2,6‐derivative is much less efficient in nucleating SSZ‐39. Interestingly, the two OSDAs that rapidly form SSZ‐39 are comparable in size whereas the methylated 2,6‐derivative is slightly smaller.