Micro-/meso-porous stannosilicate composites (Sn-MFI/MCM-41) via two-step crystallization process: Process parameter–phase relationship

Sn-MFI/MCM-41 composite material was successfully synthesized by a simple two-step crystallization process. The length of period allowed for the recrystallization of the precursor species was found to be a controlling factor to achieve either the end members viz. Sn-MCM-41 and Sn-MFI or Sn-MFI/MCM-41 composite material. [Display omitted] . ► Micro-/meso-porous stannosilicate composite (Sn-MFI/MCM-41) material has been synthesized via two-step crystallization method. ► The end member’s viz. Sn-MCM-41 and Sn-MFI can be synthesized by varying the length of period allowed in second step. ► The type of phase formed was found to depend on various process parameters such as aging time, re-crystallization temperature, time and molar gel compositions. ► In hydroxyalkylation of p-cresol with formaldehyde, combined microporous and mesoporous characteristics of Sn-MFI/MCM-41 lead to yield 59% product with 89%, 9% and 2% selectivity to DAM, trimer and carbinol respectively. Sn-MFI/MCM-41 composite material was successfully synthesized by monitoring the re-crystallization time in a simple two-step crystallization process. The length of period allowed for the recrystallization of the precursor species was found to be a controlling factor to achieve either the end members viz. Sn-MCM-41 and Sn-MFI or Sn-MFI/MCM-41 composite material. Powder XRD, FTIR, SEM, TEM, nitrogen sorption measurement, DRUV–vis and hydroxyalkylation of p-cresol reaction were used as the characterization tools. Attempts were also made to establish the relationship between type of phase formed and the process parameters such as aging time, re-crystallization temperature, time and molar ratios of TPAOH/SiO 2, CTMABr/SiO 2 and SiO 2/SnO 2 in the gel.