Special catalyst for preparing m-phthalonitrile through ammoxidation reaction as well as preparation method and application thereof

Abstract

The invention discloses a special catalyst for preparing m-phthalonitrile from m-xylene by an ammoxidation method. A carrier of the special catalyst is silica gel, a main catalyst comprises three components of V, Mo and Sb, and a cocatalyst comprises at least one of a component D and a component E; the active component of the catalyst is represented as VMoSb<c>D<d>E<e>O<x>; D is boron, chromium, titanium, phosphorus, nickel, bismuth, manganese, iron, cobalt, copper, zinc or tin; and E is potassium, lithium, sodium, caesium, magnesium or calcium. The invention also discloses a preparation method and application of the catalyst. A group containing an lone electron pair on silicon and inorganic elements are subjected to a Lewis acid-base reaction, so that the action of inorganic oxide andthe carrier is enhanced; meanwhile, the inorganic oxide is dispersed more uniformly, the catalyst component loss is less, the catalytic activity is high, the selectivity is good, and the service lifeof the industrial catalyst is prolonged from one year to two years or above. The catalyst is simple in preparation method and good in thermal stability and mechanical strength, and can be used for fixed beds and fluidized bed reactors.

Description

technical field [0001] The invention relates to a special catalyst for preparing isophthalonitrile by an ammoxidation method, a preparation method and an application. It belongs to the technical field of organic chemistry and also belongs to the technical field of organic fine chemicals. Background technique [0002] Isophthalonitrile is a high-efficiency, broad-spectrum, low-toxicity, low-residue pesticide fungicide and an intermediate of antifungal agent chlorothalonil (tetrachloroisophthalonitrile); isophthalonitrile is hydrogenated to produce M-xylylenediamine is an epoxy resin curing agent with excellent performance, and it is also a raw material for polyurethane resin and nylon resin. Isophthalonitrile has become an important chemical product, and its consumption is still on the rise. [0003] The simplest and most economical industrial production method for isophthalonitrile is to obtain m-xylene through gas-phase ammoxidation under the action of a catalyst. Since ...

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Problems solved by technology

[0004] The inventor once developed the silica gel-supported multi-component composite oxide catalyst m-509 for the ammoxidation of m-xylene, and the molar yield of isophthalonitrile can reach 66%, but after six months of operation on the industrialized device, Catalyst activity declines seriously, and the main reason for catalyst deactivation is the loss of active components on the catalyst surface (Huang Chi, Zheng Qiong, Xie Guangyong, etc. Research on deactivation of m-509 catalyst for ammoxidation of m-xylene, Journal of Wuhan University (Science Edition) , 2001, 47, 438-440)

The silica gel-supported catalyst is prepared by silica gel impregnation method, that is, silica gel absorbs the mixed metal salt solution and then activates it by high-temperature calcination; the composite metal oxide is mainly attached to the silica gel surface through physical adsorption, and the interaction between the metal oxide and the silica gel carrier is weak. In the fluidized bed reactor, the catalyst microspheres collide and rub against each other, and the metal oxide is easy to fall off. In addition, part of the components in the composite metal oxide volatilize under long-term high temperature, resulting in the loss of the active components of the catalyst and the change of the proportion. To a certain extent, it will lead to a decrease in catalyst activity and affect the service life of the catalyst

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