Chromium-free and environment-friendly catalyst for synthesis of 1,1,1,3,3,3-hexafluoro-2-butene by gas-phase fluorination

Abstract

The invention discloses a gas-phase catalytic CF 3 CHClCH 2 CCl 3 The invention discloses a chromium-free environment-friendly catalyst for synthesizing 1,1,1,3,3,3-hexafluoro-2-butene with anhydrous hydrogen fluoride and a preparation method thereof. It is to solve the environmental problems of traditional chromium-based fluorination catalysts. Extensive use of heavy metal chromium will cause a series of serious pollution and health problems, as well as the poor performance of traditional iron-based catalysts. The catalyst disclosed by the present invention consists of M / MgF 2 , where the matrix MgF 2 It has a rutile phase and a nano-spherical structure with a specific surface area greater than 120m 2 / g, high stability MgF with excellent sintering resistance at 500°C 2 , the active component M is selected from Co 3+ 、Ni 2+ , Fe 3+ , Zn 2+ , La 3+ 、Al 3+ , Ga 3+ , Mn 4+ 、Cu 2+ one or more of them. The preparation of the catalyst comprises the following steps: (1) preparing a polyol solution containing a magnesium source and doped with metal ions, adding a fluorination reagent dropwise at 150-240°C to obtain a catalyst xerogel; (2) drying the xerogel at 300-240°C Calcined at 500°C, and finally fluorinated at 150-400°C to obtain a chromium-free high-performance catalyst.

Description

technical field [0001] The invention relates to a catalyst, in particular to a gas phase catalytic CF 3 CHClCH 2 CCl 3 A chromium-free and environmentally friendly catalyst for the synthesis of 1,1,1,3,3,3-hexafluoro-2-butene by reacting with hydrogen fluoride. Background technique [0002] 1,1,1,3,3,3-hexafluoro-2-butene, referred to as HFO-1336, does not contain chlorine atoms in the molecule, and its ozone depletion potential (ODP) is zero. After entering the atmosphere, it can quickly react with OH free radicals and degrade, the atmospheric life is short (≤20d), and the GWP value is only 9, so it has little impact on the environment when used. In addition, the physical and chemical properties of HFO-1336 are equivalent to those of the existing fluorine-containing blowing agents HCFC-141b and HFC-245fa, and it has excellent foaming and heat insulation properties. economic benefits. [0003] So far, among the many known synthetic routes, CF 3 CHClCH 2 CCl 3 Synthes...

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Problems solved by technology

[0004] The gas-phase fluorination reaction catalyst reported above uses chromium as the core component. However, as a heavy metal element, chromium, a large amount of discharge will cause serious pollution to the ecological environment; especially hexavalent chromium is a highly toxic substance that is harmful to animals and human health. pose a great threat

However, Fe-based gas-phase fluorination catalysts are prepared by traditional impregnation, co-precipitation and blending methods. Large particle size, poor thermal stability, and small specific surface area lead to low catalyst activity and poor selectivity.

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