| abstract |
The invention provides a process for the manufacture of zeolites of the ZSM-5 type by heating an aqueous solution or suspension containing a silicon dioxide source, alkali metal hydroxide and optionally an aluminum source until crystallization occurs. Furthermore, the solution or suspension contains an organic phosphorus compound which is selected from the group consisting of OPR1R2R3 and PR1R2R3, in which R1, R2 and R3, independently from one another, each are alkyl or alkoxy having each from 2 to 10 carbon atoms. |