Hydrophobic aluminosilicate zeolite prodn. and stabilisation - by dealumination and then surface alumination with alkaline sodium aluminate soln., to increase stability without conversion to amorphous form

摘要

Prodn. and stabilisation of hydrophobic aluminosilicate zeolites (I), esp. dealuminated zeolitic aluminosilicates with a high Si/Al ratio, is claimed. Dealuminated aluminosilicates (II) are produced by thermochemical, extractive or substitution process stages. The surface of (II) is aluminated by treatment with NaAlO2 soln. (III) at temps. up to 90 deg.C in conventional appts., e.g. stirred vessels, fluidised beds, etc.. The novelty is that (III) is an aq. 1 x 10 power(-6) to 9.9 x 10 power(-3), pref. 1.0 x 10 power(-3) M soln. with pH 7-12.5, pref. 10. (III) may also contain non-aq. substances which are completely or partly soluble in water, e.g., alcohols, amines, ethers or esters, pref. EtOH, MeOH, BuOH, monoethylene glycol, monoethanolamine or ethyl acetate. The wt. ratio of (III) to solids is 0.1-10,000, pref. 100. ADVANTAGE - The process avoids partial conversion to an amorphous prod. and increases the stability of zeolites obtd. in technical processes.