Catalyst used for synthesis of dimethyl oxalate and preparation method thereof

Abstract

The invention provides a catalyst used for synthesis of dimethyl oxalate and a preparation method thereof. The catalyst comprises an active component of palladium and a carrier of spherical alpha-Al2O3, wherein the loading amount of palladium accounts for 0.1 to 0.5% of the mass of the carrier; palladium particles have an average particle size of 2.5 to 3 nm and a dispersity of 34 to 37%; and the spherical alpha-Al2O3 has a particle size of 1 to 3 mm and a specific surface area of 0.5 to 10 m2 / g. The catalyst is prepared through the following steps: dissolving palladium acetate in an organic solvent so as to prepare an impregnating solution, then impregnating the spherical alpha-Al2O3 in the impregnating solution for 12 to 24 hours, and carrying out drying and calcining. According to the invention, by using the organic solvent as the impregnating solution, the palladium particles on the carrier have high dispersity and small particle size. Thus, the catalyst has high reaction activity and long service life in reaction of synthesizing dimethyl oxalate from carbon monoxide and methyl nitrite.

Description

technical field [0001] The invention belongs to the field of preparation of a catalyst for synthesizing dimethyl oxalate in a coal-to-ethylene glycol process, and in particular relates to a catalyst for synthesizing dimethyl oxalate through gas-phase catalytic coupling of carbon monoxide and a preparation method thereof. Background technique [0002] Dimethyl oxalate is an important organic chemical raw material, which can be used to manufacture oxalic acid, oxamide, ethylene glycol, etc. In 1980, Japan's UBE Corporation and the United States' United Carbon Corporation successively disclosed carbon monoxide, methyl nitrite or ethyl nitrite as raw materials, and loaded Pd / α-Al 2 o 3 As a catalyst, to catalyze the method of carbon monoxide coupling to synthesize dimethyl oxalate or diethyl oxalate. Subsequently, Ube Industries has carried out a lot of research work on the development of high-efficiency catalysts and optimization of process flow, and built an industrial demon...

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Problems solved by technology

Patent CN1066070 reports a kind of Pd-Zr / Al 2 o 3 The preparation method of catalyst, although the catalyst prepared by this method has higher reactivity, selectivity and long life-span, but the loading of active component palladium is more than 1%, which undoubtedly increases the production cost of the catalyst

Patent 201410435876.9 reported a Pd / α-Al prepared by anion regulation method 2 o 3 The catalyst, the loading of the active component palladium is 0.05-1%. Although the catalyst prepared by this method has higher activity, the ion regulation step is added in the early stage of the catalyst preparation process, and the chlorine removal process is added in the later stage, so that the catalyst The preparation process is more complicated

At present, in the relevant patents of carbon monoxide gas-phase catalytic coupling synthesis dimethyl oxalate catalyst, the impregnating solution used is all prepared by dissolving the active component precursor in water, and this impregnating solution causes the active component palladium ion to The dispersion on the carrier is not uniform enough and the particles are large, and the catalyst activity is poor, so that the reaction cannot run for a long time

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