Special catalyst for preparing 2, 6-dichlorobenzonitrile by ammonia oxidation method and preparation method and application of special catalyst

Abstract

The invention discloses a special catalyst for preparing 2, 6-dichlorobenzonitrile by an ammonia oxidation method. The special catalyst is a multi-component inorganic composite oxide loaded by a silica gel-carbon nitride composite carrier, and the composition of the active component of the catalyst is shown as VMobBcCodDeOx, wherein D is lithium, sodium, potassium, rubidium, cesium, magnesium, calcium or barium. The invention also discloses a preparation method and application of the catalyst. Organic matters containing nitrogen and carbon and silica sol are respectively added as precursors ofcarbon nitride and silica gel for mixed calcination to form the silica gel-carbon nitride composite carrier. compared with a common silica gel carrier, the silica gel-carbon nitride composite carrierhas the advantages that the effects of the inorganic oxide and the carrier are enhanced, the strength and the wear resistance of the catalyst are improved, the inorganic oxide is dispersed more uniformly, the loss of catalyst components is reduced, and the service life of the catalyst is prolonged; meanwhile, the carbon nitride can also adjust the acid-base property, oxidation-reduction capability and coordination capability with reactants of the catalyst so that the activity and the selectivity of the catalyst are improved. The catalyst is simple in preparation method and good in thermal stability and mechanical strength.

Description

technical field [0001] The invention relates to a special catalyst for preparing 2,6-dichlorobenzonitrile by an ammoxidation method, a preparation method and application thereof. It belongs to the technical field of organic chemistry and also belongs to the technical field of organic fine chemicals. Background technique [0002] 2,6-dichlorobenzonitrile is also known as 2,6-dichlorobenzonitrile. As a high value-added fine chemical, chlorobenzonitrile is a key raw material for the manufacture of some high-efficiency and low-toxicity pesticides, new medicines, high-performance materials, dyes, etc., and is widely used in various fields of the national economy. [0003] 2,6-Dichlorobenzonitrile (2,6-DCBN) is mainly an essential intermediate of ultra-efficient, pollution-free, and low-residue "benzoylurea" pesticides. At present, the use, sale and production of low-efficiency and high-toxic pesticides have been banned by law in my country, so there is an urgent need for a larg...

AI Technical Summary

Problems solved by technology

[0005] There are more than ten kinds of preparation methods for 2,6-dichlorobenzonitrile, generally using corresponding aldehydes, aldoximes or acids as raw materials. These methods have high raw material prices, long reaction routes, low product yields and low reaction selectivity. serious environmental pollution

Most of the measures in the above patents complicate the production process and increase the investment; or cause equipment corrosion and low product purity.

Martin et al prepared 2,6-dichlorobenzonitrile with the unloaded VPO composite oxide prepared by sol-gel method as ammoxidation catalyst, the product yield is low, and it is difficult to reach the requirements of industrial production; in addition, the catalyst mechanism Not strong enough to be used in fluidized bed reactors (Journal of Catalysis, 2006, 240:8-17; Catalysis Today, 2009, 142: 158-164)

In Chinese patent CN1055028C, V is prepared by silica gel impregnation method. a Ti b P c Cr d o x The four-component silica gel-supported catalyst catalyzes the ammoxidation of 2,6-dichlorotoluene to prepare 2,6-dichlorobenzonitrile, and the yield can reach 85%. However, the silica gel-supported catalyst generally has a short service life in industry.

The catalysts used in these patents are still difficult to meet the industrial requirements for high catalyst strength, long life, high load, high activity and high selectivity

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