Palladium compound being stable in acetylene atmosphere at high temperature, and application thereof

Abstract

The invention provides a palladium compound PdSxCl2-2x (wherein x is more than 0 and less than 1) being stable in an acetylene atmosphere at a high temperature and having a catalysis activity on acetylene hydrochlorination for synthesizing vinyl chloride. The palladium compound comprises a porous solid carrier and a PdSxCl2-2x compound supported on the surface of the porous solid carrier, the PdSxCl2-2x compound is a PdSxCl2-2x ionic compound formed through using Pd as the core and bonding S and Cl with Pd through ionic bonds, wherein x is more than 0 and less than 1, the loading quantity of the Pd element is 0.05-1% of the weight of the carrier, and the loading quantity of the S element is 0.1-5% of the weight of the carrier. The ionic bonds between Pd and S and between Pd and Cl in the PdSxCl2-2x compound formed through introducing the S element to the PdSxCl2-2x compound are stronger than ionic bonds of PdCl2 or [PdCl4]<2->, so sublimation induced loss of a complex formed by the PdSxCl2-2x compound used as an active site and C2H2 is difficult, thereby the stability of the supported palladium catalyst in an acetylene hydrochlorination reaction is improved.

Description

technical field [0001] The invention belongs to the technical field of catalyst materials, and in particular relates to a palladium complex which is stable at high temperature in an acetylene atmosphere and has the activity of catalyzing the hydrochlorination of acetylene to synthesize vinyl chloride. Background technique [0002] Vinyl chloride is the monomer of polyvinyl chloride (PVC), one of the five largest synthetic resins in the world, and is mainly produced by the calcium carbide acetylene method and the petroleum ethylene method. China's coal-rich, oil-poor, and gas-poor energy reserves determine that the calcium carbide acetylene method will continue to be the main process for the production of vinyl chloride in my country for a long time to come, that is, mercuric chloride catalyzes the reaction of acetylene and hydrogen chloride to produce vinyl chloride. However, the highly toxic mercuric chloride catalyst seriously pollutes the environment and endangers human h...

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Problems solved by technology

(3) in PdCl 2 Addition of BiCl to the catalyst system 3 Partially inhibited carbon deposition, but could not effectively inhibit PdCl 2 PdCl formed with acetylene 2 ·C 2 h 2 Sublimation loss of the complex [Sichuan Chemical Industry, 2007,10(5):13-15]

(3) Use Y-type zeolite instead of activated carbon as a carrier, add KCl additive or NH 4 F modified Y zeolite carrier, etc., but still failed to inhibit PdCl 2 PdCl formed with acetylene 2 ·C 2 h 2 Sublimation loss of the complex [Wang et.al., Reaction Kinetics Mechanisms & Catalysis, 2013, 110(1): 187-194;

The point of view of this literature is different from that of most supported gold catalysts, but it is difficult to provide a reference for improving the loss and deactivation of supported palladium catalysts

[0007] In summary, improving the stability of supported palladium-based catalysts in acetylene hydrochlorination is still a major unsolved challenge. Although adding additives and other methods can slow down its loss, the modified method The catalyst stability is still unsatisfactory, which shows that the activity of the catalyst decreases significantly during the long-term evaluation time, and the problem of the loss of active components has not been fundamentally solved, mainly because the structure and composition of the active center have not changed. Adding sulfur-containing compounds as promoters to supported gold catalysts can improve its catalytic performance, but the mechanism of promoters mentioned in the existing literature is not suitable for improving the deactivation of supported palladium catalysts due to sublimation