Patent ID: 6656447
Filing Date: 2003-12-02
Classification: C01B,Y10S

Abstract:
A process for controlling the particle size and particle size distribution of a molecular sieve during its synthesis, the molecular sieve having an empirical formula on an anhydrous basis of:rR2O:(SixAlyPz)O2â€ƒâ€ƒ(I) where R is at least one templating agent, â€œrâ€  has a value of 0 to about 1.0; â€œxâ€ , â€œyâ€  and â€œzâ€  are the mole fractions of silicon, aluminum and phosphorus respectively, â€œxâ€  has a value from 0 to about 1.0, â€œyâ€  has a value from 0 to about 0.6, â€œzâ€  has a value from 0 to about 0.545, x+y+z=1, x+y>0, and when x>0 and y=0, then z=0, the process comprising:a) continuously introducing separate streams comprising reactive sources of at least each framework element, according to formula (II), into a continuous crystallization reactor having at least two stages, thereby forming a reaction mixture having a formula expressed in terms of molar ratios of: aR2O:(SibAlcPd)O2:eH2Oâ€ƒâ€ƒ(II) â€ƒwhere R is at least one structure directing agent, â€œaâ€  has a value of greater than 0 to about 5; â€œbâ€  has a value of about 0 to about 1.0; â€œcâ€  has a value of 0 to about 1.0, â€œdâ€  has a value of 0 to about 1.0 and â€œeâ€  has a value from greater than zero to about 500, b+c+d=1; b+c>0; and when b>0 and c=0, then d=0; b) flowing the reaction mixture through said continuous reactor, at reaction conditions, thereby crystallizing the molecular sieve; c) controlling the particle size and particle size distribution of the molecular sieve by introducing an effective amount of interstage backmixing or by adjusting the number of stages in the reactor, and; d) recovering the molecular sieve.