| 简介 |
FIELD : chemistry.
SUBSTANCE : method of producing an ultrastable Y type zeolite involves four ion exchanges of sodium cations for cations of rare earth elements and ammonium in NaY zeolite and two stages of ultrastabilisation of zeolite in a water vapor medium. In the fourth stage of ion exchange, citric or tartaric acid is introduced in an amount of 1.0-1.5 mmol per gram of zeolite to produce a zeolite Y with a lattice silica module of more than 20. The specific surface area of the zeolite is from 500 to 800 m2/g, the content of sodium oxide is not more than 0.5 wt %, the content of rare earth oxides is from 0.5 to 5.5 wt %, alumina from 18 to 22 wt %. The acidity by thermal desorption of ammonia is from 0.3 to 0.8 mmol per gram of zeolite.
EFFECT : obtaining an ultrastable zeolite Y with an elevated silica module.
1 tbl, 7 ex |
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