Pd/Ce-F/MCM-48 catalyst as well as preparation method and application thereof

Abstract

The invention discloses a Ce-F / MCM-48 mesoporous material and a Pd catalyst with the Ce-F / MCM-48 mesoporous material as a carrier. According to the invention, Ce-F / MCM-48 is synthesized by using a NaF and Ce in-situ doping hydrothermal synthesis method, and the Pd-loaded Pd / Ce-F / MCM-48 bimetallic catalyst taking Ce-F / MCM-48 as a carrier is prepared by using an impregnation method. The catalytic performance of the catalyst on the n-heptane isomerization reaction is investigated. Results show that the molecular sieve prepared after NaF doping has the advantages that the specific surface area and the pore volume are increased, the pore size distribution tends to be uniform, and the acidity is mild and moderate. When the optimal loading capacity of the noble metal Pd is 0.4% by mass, the reaction temperature is 280 DEG C and the reaction time is 120 min, the catalytic performance is relatively stable, the conversion rate of n-heptane isomerization is 79.7%, and the selectivity of isoheptane is 91.5%. The catalyst is expected to be an important catalyst for hydroisomerization of n-heptane.

Description

technical field [0001] The invention belongs to the technical field of catalysts, and in particular relates to a Pd / Ce-F / MCM-48 catalyst and a preparation method and application thereof. Background technique [0002] The quality upgrade of FCC gasoline will be the main problem that my country must face and solve in the next few years. Converting straight-chain alkanes to branched-chain alkanes is the most important means to ensure gasoline octane number. Therefore, the preparation of heptane isomerization catalysts has also attracted much attention. At present, most of the heptane isomerization catalysts are prepared by supported metal catalysts. The properties of the support have a great influence on the catalyst. In the preparation of support materials, scientists from Mobil Corporation first reported the synthesis of M41S in the early 1990s [BeckJ S, Vartuli J C, Roth W J, et al. A new family of mesoporous molecular sieves prepared with liquid crystal templates[J].J.am...

AI Technical Summary

Problems solved by technology

[0003] However, since the MCM-48 silicon-oxygen tetrahedron is a charge balance system, there are few lattice defects in the pure silicon mesoporous molecular sieve framework, the concentration of acid centers on the surface is low, and it does not have the ability to catalyze oxidation reactions, so it usually cannot be directly used as a catalyst. Mesoporous molecular sieves are functionally modified. The most common modification method is heteroatomization for different catalytic reactions. Another important carrier modification method is to introduce anions into the molecular sieve framework. There are still few researches on the modification of catalysts, and it is still our goal to develop new catalysts by using different materials to mine catalysts with high-quality factors, understand their coordination environment and catalytic performance, and develop new catalysts.

Images