Dual-function catalyst applied to isomerization of C8 aromatic hydrocarbon and preparation method of dual-function catalyst

Abstract

The invention discloses a dual-function catalyst applied to isomerization of C8 aromatic hydrocarbons and a preparation method of the dual-function catalyst. The catalyst is prepared from the following components: 10-89.9wt% of H type hierarchical-pore structure EUO molecular sieve, 9.9-89.9wt% of matrix and 0.01-2.0wt% of metal active component. The preparation method comprises the following steps: mixing the hierarchical-pore EUO molecular sieve, the matrix and a pore-enlarging agent, then adding an acid solution, kneading and forming, drying and roasting to remove the components such as thepore-enlarging agent to form a carrier, then dipping the carrier in a mixed solution containing metal salt and activating to obtain a formed catalyst. The hierarchical-pore EUO molecular sieve is crystallized and synthesized by taking a long-chain silane compound as a crystallization promoting agent and taking biquaternary ammonium salt with an alkane structure substituted by a di-penta-heterocycle group as an organic template agent. The catalyst shows favorable activity and selectivity in hydroisomerization reaction of C8 aromatic hydrocarbon and has a good industrial application prospect and a good economic value.

Description

technical field [0001] The invention relates to a bifunctional catalyst for the isomerization of C8 aromatic hydrocarbons and a preparation method thereof, belonging to the field of preparation of inorganic catalytic materials. Background technique [0002] C 8 Aromatics are a mixture of p-, m-, ortho-xylene and ethylbenzene, which can be obtained from catalytic reforming, petroleum cracking and other processes, among which p-xylene (PX) and o-xylene (OX) are important chemical raw materials , such as the basic raw material for polyester and phthalic anhydride. With the development of these industries, the demand for PX and OX is increasing rapidly. At present, the process technology for increasing the production of PX and OX is mainly xylene isomerization, which is an important means to convert m-xylene and ethylbenzene with low utilization value into PX and OX. Since the boiling points of ethylbenzene and xylene are very close, the separation is difficult, resulting in ...

AI Technical Summary

Problems solved by technology

While catalysts based on ZSM-5 zeolite, which can be used alone or in combination with other zeolites such as mordenite, do not provide the best performance

[0006] CN1901991A discloses a kind of C 8 Aromatics isomerization catalyst, using MTW type zeolite or low silica ZSM-12 as the acidic component, platinum and germanium as active metal components, when the above catalyst is applied to the isomerization of C8 aromatics, although the conversion rate of ethylbenzene is relatively low High, but the loss rate of xylene is high, indicating that there are many side reactions, the selectivity of the catalyst is poor, and the p-xylene in the product stream has not reached the equilibrium quantity

[0010] The EUO structure molecular sieve preparation methods disclosed in the above documents mainly include traditional hydrothermal method and solid-phase in-situ method, but the molecular sieve structure is basically the same, its particle size is generally large, all in the micron level, and miscellaneous crystals are prone to appear. The lifespan is severely limited, and the product yield needs to be improved

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