Alkali-free synthesis of Al-MTW using 4-cyclohexyl-1,1-dimethylpiperazinium hydroxide as structure directing agent

Synthesis of MTW-type zeolites was carried out for the first time using 4-cyclohexyl-1,1-dimethylpiperazinium hydroxide as structure directing agent. An alkali-free and fluoride-free synthesis procedure for incorporation of aluminum into the MTW-framework was developed. Products were characterized using XRD, FE-SEM, HR-TEM, EDXS, ICP-OES, N2-sorption, Ar-sorption and NH3-TPD. The Al-MTW product from this new synthesis route is stable after calcination at 600 °C and has an open pore/channel system. The Si/Al ratio of the Al-MTW crystals was found to be 50. The NH3-TPD studies demonstrated that the new Al-MTW product has strong acid sites and can be directly utilized as a solid acid catalyst without going through any ion-exchange procedures. Utilization of seed crystals in Al-MTW synthesis was also investigated and its influence on product morphology was identified.

Synthesis of MTW-type zeolites was carried out for the first time using 4-cyclohexyl-1,1-dimethylpiperazinium hydroxide as structure directing agent. An alkali-free and fluoride-free synthesis procedure for incorporation of aluminum into the MTW-framework was developed. The Al-MTW product has strong acid sites and can be directly utilized as a solid acid catalyst without going through any ion-exchange procedures..Figure optionsDownload as PowerPoint slideHighlights
► Synthesis of MTW zeolites using 4-cyclohexyl-1,1-dimethylpiperazinium hydroxide.
► Alkali-free and fluoride-free synthesis of Al-MTW.
► Al-MTW with strong acid sites obtained without any ion-exchange.
► Effect of seed crystals in Al-MTW synthesis.