Molecular sieves and process for their manufacture
AssigneeExxon Chemical Patents Inc.
InventorsMarc H. Anthonis, Antonie Jan Bons, Johannes P. Verduijn
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Abstract
Mixtures of synthesis mixtures of different alkalinity's produce small MFI crystals that are not spherical.
Claims27
A process for the manufacture of an MFI zeolite which comprises mixing (a) an aqueous alkaline synthesis mixture comprising a silica source and an organic template, the synthesis mixture having a molar OH—:SiO2 ratio of no greater than about 1.4:1, with (b) an active synthesis mixture being an active mother liquor which is derived from an aqueous synthesis mixture which has been used for at least one crystallization and the formed crystals having been removed,
- and subjecting the mixture of (a) and (b) to hydrothermal treatment to induce crystallization.
A process for the manufacture of an MFI zeolite which comprises mixing (a) an aqueous alkaline synthesis mixture comprising a silica source and an organic template, the synthesis mixture having a molar OH—:SiO2 ratio of no greater than about 1.4:1, with (b) an active synthesis mixture comprising an aged aqueous alkaline synthesis mixture comprising a silica source and an organic template, the aged synthesis mixture having a molar OH—:SiO2 ratio of at least 0.1:1 and a molar organic template:
- SiO2 ratio within the range of 0.1 to 0.5:1, and subjecting the mixture of (a) and (b) to hydrothermal treatment whereby MFI zeolite crystals are formed having a mean length of the largest dimension of the crystals of not more than of 550 nm.
An MFI molecular sieve of crystallite size within the range of 110 to 200 nm, the ratios of the dimension of which are in the ranges 0.3 to 0.4:0.7 to 0.8:1.
An MFI molecular sieve of crystallite size within the range of from 200 to 550 nm, the ratios of the dimensions of which are in the ranges of 0.2 to 0.3 to 0.7:1.
An MFI molecular sieve of three dimensional crystallite size such that the mean length of the largest dimension of the crystals is in the range of 100 to 550 nm, the mean length of the smallest dimension of said crystals being at most half of the largest crystal dimension and the mean length of an intermediate dimension of said crystals being in the ratio of 0.6 to 0.8:1 with respect to said largest dimension.
Dependencies are inferred from the claim text.