La/Hβ-Al₂O₃ composite materials improve light gasoline etherification activity

The La/Hβ-Al₂O₃ composite materials were prepared by method of lanthanum ion-exchange and used to improve the low-temperature etherification activity of light gasoline. The physical chemical properties of composite materials were characterized by a series of analytical methods, such as XRD, XRF, BET, FTIR, NH₃-TPD, PyIR and FETEM-EDX. The results of XRD, XRF, BET and FTIR show that introduction of a small amount of lanthanum ions has no obvious effect on the crystalline phase and skeleton structure of the composite materials, on the contrary, moderate lanthanum ion exchange has the effect of pore-enlarging. The analysis results of NH₃-TPD and PyIR show that acid content and acid strength of the composite materials have been weakened, but the introduction of lanthanum ions can form a new Brønsted acid site, which increases the ratio of medium strong acid and the amount of Brønsted acid sites. The results of FETEM-EDX analysis confirm that the lanthanum species are mainly present in the Hβ molecular sieve of composite materials. The evaluation results of etherification activity of this composite material show that the method of lanthanum ion-exchange can improve the light gasoline etherification activity of composite catalyst, in which the sample 0.1 La/Hβ-Al₂O₃ shows the best activity, and the yield of methyl tertiary amyl ether is up to 58.13%. The 300 h life test results show that it has good stability and reproducibility.