Vulcanized ionic liquid complex palladium catalyst, and preparation method and applications thereof

Abstract

The invention discloses a vulcanized ionic liquid complex palladium catalyst, and a preparation method and applications thereof. According to the preparation method, an ionic liquid is subjected to sulfuration modification to introduce sulfur containing groups, and the treated ionic liquid is loaded with PdCl2 precursor so as to form a Pd-S-IL system with a special structure, and increase both thereaction activity and the stability of the palladium catalyst. The supported ionic liquid promoted palladium catalyst possesses relatively high stability in ethyne hydrochlorination, after 6000h of operation, no palladium loss is detected, the highest ethyne conversion rate is 99.8%, and the highest vinyl chloride selectivity is 99.95%.

Description

Background technique [0001] Polyvinyl chloride (PVC) is an important general-purpose plastic. Due to the energy storage characteristics of rich coal, poor oil and little gas in my country, the preparation of vinyl chloride by calcium carbide acetylene method is the mainstream process of polyvinyl chloride production in my country. Mercury chloride is currently used as a catalyst for the synthesis of vinyl chloride in the industry. Because it causes serious pollution to the environment, and the synthesized polyvinyl chloride contains a small amount of mercury, the application of polyvinyl chloride is limited. Therefore, the mercury chloride catalyst will be gradually eliminated, and the synthesis of vinyl chloride under the condition of mercury-free catalyst will become the main direction for the future sustainable development of calcium carbide method PVC. Mercury-free catalysts mainly use metal chlorides as active components, among which noble metal chlorides exhibit the bes...

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Problems solved by technology

[0014] Chinese patent application (CN 102357336 A) discloses using molecular sieves such as HZSM-5, NaZSM-5, and zeolite as carriers to support PdCl 2 The prepared catalyst, at the feed gas ratio V (HCl) / V (C2H2) Under the condition of =1.15, the acetylene hydrochlorination reaction performance test was carried out at 160 °C, and the reaction tail gas was analyzed. The initial conversion rate of acetylene of the catalyst was 89.78%, and the selectivity of vinyl chloride was 98.62%. The catalyst activity was low and did not meet the requirements of industrialization

Chinese patent CN101716528 discloses an ionic liquid dissolving metal chlorides such as gold, platinum, palladium, tin, mercury, copper or rhodium as a catalyst system, which is applied to acetylene hydrochlorination, but the reaction system belongs to a gas-liquid reaction system, and there is The mass transfer efficiency of reactants and products is low, stirring or pneumatic stirring is easy to cause the loss of catalyst active components, etc., and the industrial application of large-scale production equipment is particularly limited.

[0019] 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 stability of the catalyst 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

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