Modified H-BEA Zeolites from Fluorinated Silica Slag Waste by Dry Gel Conversion Method for Shape-Selective Acylation of 2-Methoxynaphthalene

The high value-added utilization of the fluorinated silica slag (FSS) waste, an associated by-product of the anhydrous HF production from the accompanying fluorine resources in phosphate ore, is of great importance, but it remains a challenge. In this work, the Mg modified and unmodified H beta zeolites from FSS waste were successfully prepared by a green dry gel conversion crystallization method with tetraethylammonium hydroxide (TEAOH) as a structure-directing agent (SDA). The in situ Mg modified H beta zeolite (Mg-H beta) shows much superior catalytic performance to unmodified (H beta) and post Mg-modified H beta (Mg/H beta) zeolites for acetylation of 2-methoxynaphthalene (2-MN) to 6-acetyl-2-methoxynaphthalene (2,6-AcMN), and the 40.2 % of conversion for 2-MN with 66.3 % of selectivity for 2,6-AcMN were achieved, ascribed to the high amount of B acidic sites and the promoted shape-selective catalysis effect by higher surface area and volume of micropores. This work not only opens a new avenue for the high value-added utilization of fluorinated silica slag waste, but also generates an efficient solid acid catalyst for the clean production of 2,6-AcMN through the acetylation of 2-MN with acetic anhydride.