Palladium catalyst for synthesis of indoxacarb intermediates and preparation method

Abstract

The invention discloses a palladium catalyst for the synthesis of indoxacarb intermediates. A carrier, an active component and a metal-assisting component are included, wherein the active component and the metal-assisting component are loaded on the carrier, the carrier is a mixture of activated carbon and carbon nanotubes, the active component Is Pd, the metal-assisting component is Fe, the masspercentage content of Pd in a catalyst is 5%, and the mass percentage content of Fe is 0.5%-2.5%. In addition, the invention further discloses a method for preparing the catalyst. The mixture of the activated carbon and the carbon nanotubes are used as the carrier, so that active component particles of the catalyst can be distributed in a large range, an important role is played in the stability of the catalyst, dopamine is used for carrying out oxidative self-polymerization reaction in an alkaline solution to generate polydopamine, the carrier is modified, the hydrophilicity of the carrier isimproved, and the uniform distribution of metal ions is facilitated. The catalyst has high activity and selectivity, the stability is good, and the repeatability is high.

Description

technical field [0001] The invention belongs to the technical field of preparation of precious metal catalysts, and in particular relates to a palladium catalyst for synthesizing an indoxacarb intermediate and a preparation method thereof. Background technique [0002] Indoxacarb is the latest high-efficiency insecticide. Its mechanism of action is a sodium channel inhibitor, which mainly blocks the sodium channel in the nerve cells of pests, resulting in coordinated paralysis and eventual death of target pests. This variety has a wide insecticidal spectrum and quick effect, and has excellent control effect on resistant pests such as beet armyworm, diamondback moth, and cotton bollworm. [0003] In addition, the agent has no teratogenicity, carcinogenicity, and mutagenicity, and is also very safe to birds, aquatic organisms, and non-target substances. Because indoxacarb is safer to operate and very friendly to the environment, it has replaced part of the market share of car...

AI Technical Summary

Problems solved by technology

[0007] Patent CN104230838A added the dehalogenation inhibitor morpholine during the hydrogenation process of the indoxacarb intermediate, which effectively reduced the dechlorination by-products, but most of the dehalogenation inhibitors were organic compounds, which were difficult to remove in the subsequent preparation of indoxacarb , affect product quality, and dehalogenation inhibitors will reduce the activity of the catalyst, make the reaction time longer, increase the amount of palladium carbon catalyst, and increase the production cost

Patent CN106732714B provides a preparation method of a 10% Pd / C catalyst for the synthesis of indoxacarb intermediates, which adopts an impregnation method to load a soluble salt of palladium on activated carbon to obtain a palladium-carbon catalyst; using the prepared palladium-carbon as a precursor, Ethylenediamine is the nitrogen source, and the aminated palladium-carbon catalyst is prepared by adjusting the reaction temperature, atmosphere, time and the molar ratio of ethylenediamine to palladium, although the product produced by using the dehalogenation inhibitor in the reaction process is avoided. Separation, but the amination process is to put the prepared palladium-carbon catalyst, ethylenediamine and solvent into the reactor, adjust the reaction temperature to 30°C-300°C, charge hydrogen to 0.5MPa and start stirring, react for 8 hours, cool down, The solvent is washed and filtered to obtain the aminated palladium-carbon catalyst. The process is complicated and time-consuming, and organic solvents such as methanol are needed, which is difficult to operate and is not conducive to industrial production.

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