Siliceous offretite
AssigneeExxon Chemical Patents Inc.
InventorJohannes Petrus Verduijn
Life of this patent
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Abstract
Zeolite crystals having an offretite structure have smaller crystals and/or can be produced using a synthesis mixture of lower alkalinity than could otherwise be used, if a divalent metal cation, such as magnesium, barium or cobalt is included in the synthesis mixture.
Claims18
A process for producing a zeolite with an offretite crystal structure and which contains a non-exchangeable amount of divalent metal cation, which process comprises crystallizing a synthesis mixture comprising sources of M'.sub.2 O, where M' is an alkali metal which is potassium or a mixture of potassium and sodium, Al.sub.2 O.sub.3, SiO.sub.2, a tetramethylammonium ion and a divalent metal cation M.sup.2+, and comprising the following molar ratios:
- ______________________________________ M'.sub.2 O/SiO.sub.2 0.12 to 0.4 SiO.sub.2 /Al.sub.2 O.sub.3 7 to 13 TMA/SiO.sub.2 0.04 to 0.12 H.sub.2 O/M'.sub.2 O 40 to 135, ______________________________________
- wherein TMA represents said tetramethylammonium ion, said synthesis mixture containing said divalent metal cation at a level sufficient to promote the formation of smaller zeolite crystals than an otherwise identical synthesis mixture which does not contain said added divalent metal cation, said level not exceeding 900 ppm, when the divalent cation is barium.
A synthetic zeolite with an offretite crystal structure which contains a non-exchangeable amount of a divalent metal cation, said zeolite crystallized from a synthesis mixture comprising sources of M'.sub.2 O where M' is an alkali metal which is potassium or a mixture of potassium and sodium, and also containing said divalent metal cation at a level sufficient to promote the formation of smaller zeolite crystals than an otherwise identical synthesis mixture which does not contain said added divalent metal cation, said level not exceeding 900 ppm, when the divalent cation is barium.
Dependencies are inferred from the claim text.