Abstract: A solid acid catalyst has a macropore specific volume of about 0.30-0.50 ml/g, a ratio of macropore specific volume to specific length of catalyst particles of about 1.0-2.5 ml/(g·mm), and a ratio of specific surface area to length of catalyst particles of about 3.40-4.50 m2/mm. The macropore refers to pores having a diameter of more than 50 nm. An alkylation catalyst is based on the solid acid catalyst and can be used in alkylation reactions. The solid acid catalyst and alkylation catalyst show an improved catalyst service life and/or trimethylpentane selectivity when used in the alkylation of isoparaffins with olefins.

Abstract: The present disclosure relates to a solvent-free moisture curing silicone conformal coating used for the surface protection of circuit boards in the electrical and electronic industries and a preparation method thereof. The solvent-free moisture curing silicone conformal coating comprises (A) a hydrolyzable functional group-terminated linear polysiloxane (I); (B) a hydrolyzable functional group-containing silicone resin with a three-dimensional structure (II); (C) a hydrolyzable functional group-containing crosslinking agent; (D) a catalyst; (E) an adhesion promoter. The solvent-free conformal coating of the present disclosure has low viscosity, high strength and good toughness, and can meet the traditional coating process such as spraying, brushing, dipping, etc., while satisfying the surface protection of the circuit board.

Abstract: A NaY molecular sieve with an aluminum-rich surface is prepared using a process that includes the steps of: a. mixing a directing agent and a first silicon source to obtain a first mixture, wherein the directing agent has a molar composition of Na2O:Al2O3:SiO2:H2O=(6-25):1:(6-25):(200-400); b. mixing the first mixture obtained in the step a with a second silicon source, an aluminum source and water to obtain a second mixture; c. carrying out hydrothermal crystallization on the second mixture obtained in the step b, and collecting a solid product. Calculated as SiO2, the weight ratio of the first silicon source to the second silicon source is 1:(0.01-12). The NaY molecular sieve has larger aluminum distribution gradient from the surface to the center of the particle than the conventional molecular sieve.

Abstract: A solid acid catalyst has a macropore specific volume of about 0.30-0.50 ml/g, a ratio of macropore specific volume to specific length of catalyst particles of about 1.0-2.5 ml/(g·mm), and a ratio of specific surface area to length of catalyst particles of about 3.40-4.50 m2/mm. The macropore refers to pores having a diameter of more than 50 nm. An alkylation catalyst is based on the solid acid catalyst and can be used in alkylation reactions. The solid acid catalyst and alkylation catalyst show an improved catalyst service life and/or trimethylpentane selectivity when used in the alkylation of isoparaffins with olefins.

Abstract: A NaY molecular sieve with an aluminum-rich surface is prepared using a process that includes the steps of: a. mixing a directing agent and a first silicon source to obtain a first mixture, wherein the directing agent has a molar composition of Na2O: Al2O3: SiO2: H2O=(6-25): 1: (6-25): (200-400); b. mixing the first mixture obtained in the step a with a second silicon source, an aluminum source and water to obtain a second mixture; c. carrying out hydrothermal crystallization on the second mixture obtained in the step b, and collecting a solid product. Calculated as SiO2, the weight ratio of the first silicon source to the second silicon source is 1: (0.01-12). The NaY molecular sieve has larger aluminum distribution gradient from the surface to the center of the particle than the conventional molecular sieve.