| 摘要 |
The present invention relates to a process for the preparation of a large-pore molecular sieve, comprising crystallising the molecular sieve from a starting mixture at a pH in the range of from 3 to 8, and recovering a large-pore molecular sieve, the said starting mixture having a molar composition satisfying the following molar ratios: (0.01 - 2) R2/nO) : (0 - 1.5) M2/mO : (0 - 0.5) X2O3 : 1 YO2 : (5 - 1,000) H2O : (0.01 - 3) F-, wherein n and m are the weighted average valences of R and M respectively, M is an alkali- or alkaline-earth metal, X is a trivalent metal and Y is a tetravalent element, wherein R comprises at least one main organic template Rm having the formula R1R2R3R4Q+ wherein Q is nitrogen or phosphorus and wherein at least one and at most three of R1, R2, R3 and R4 is an aryl or alkyl group having 6 to 36 carbon atoms and each of the remainder of R1, R2, R3 and R4 is selected from hydrogen and an alkyl group having 1 to 5 carbon atoms. The invention further relates to a calcined large-pore molecular sieve and its use.
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