Seed-solution-induced Synthesis of FER Zeolite and Its Catalytic Application in the Skeletal Isomerization of n-Butene

A series of Ferrierite(FER)zeolites were prepared via hydrothermal synthesis in the absence of organic templates with the aid of sodium-type FER zeolite(NaFER)or NaFER suspensions(NaFERsus)acquired by NaOH solution treatment as seeds.The differences in the structures and acid sites of the obtained FER zeolite catalysts arising from the choice of seed were investigated,and the catalytic performances of the obtained FER zeolites were evaluated in the skeletal isomerization of n-butene.The results indicate that the samples synthesized using NaFERsus feature more Br?nsted acid sites(BAS)in the 10-membered-ring(10-MR)at the expense of strong acid and Lewis acid sites(LAS),compared with samples derived from NaFER.Therefore,the FER samples synthesized using NaFERsus outperformed the NaFER counterparts as the BAS in 10-MR and LAS were the main active sites,while BAS in 8-MR and LAS were responsible for side reactions,such as polymerization,cracking,and carbon deposition in n-butene isomerization.The optimized FER catalyst was continuously used for 720 h at 350℃ at 0.1 MPa under an n-butene space velocity of 2.0 h^(-1),during which the n-butene conversion remained at>40%,and the isobutylene yield was>37.5%.

Synthesis of FER zeolite with piperidine as structure-directing agent and its catalytic application

The synthesis of ferrierite(FER)zeolite using piperidine as an organic structure‐directing agent was investigated.X‐ray diffraction,X‐ray fluorescence,N2‐adsorption,and scanning electron microscopy were used to characterize the crystal phases,textural properties,and particle morphologies of the zeolite samples.The crystallization behavior of the FER zeolite was found to be directly related to crystallization temperature.At150?C,pure FER phase was observed throughout crystallization.At160–170?C,MWW phase appeared first and gradually transformed into FER phase over time,indicating that the FER phase was thermodynamically favored.In the piperidine‐Na2O‐H2O synthetic system,alkalinity proved to be the crucial factor determining the size and textural properties of FER zeolite.Furthermore,the obtained FER samples exhibited good catalytic performance in the skeletal isomerization of1‐butene.