Metal oxide catalyst for synthesizing methyl carbonate by urea process and its prepn

A technology for dimethyl carbonate and oxides, applied in the field of metal oxide catalysts for dimethyl carbonate and its preparation, can solve the problems of difficult separation and recovery of homogeneous catalysts, low equilibrium conversion rate, etc., and achieve easy separation and recovery, high activity High and stable effect

Inactive Publication Date: 2003-05-14
HEBEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In view of the above problems, the present invention solves the problems of low equilibrium conversion rate and difficult separation and recovery of homogeneous catalysts in the prior art, thereby providing a series of metal oxide catalysts for urea synthesis of dimethyl carbonate and preparation methods thereof

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Embodiment 1: (pyrolysis method prepares single metal oxide---zinc oxide catalyst)

[0036] Basic zinc carbonate was calcined in a muffle furnace at 550° C. for 2 hours to obtain a zinc oxide catalyst.

[0037] The catalyst sample has been tested by XRD to prove that there is only one crystal phase of ZnO, which belongs to the hexagonal crystal system.

[0038] Catalyst catalysis urea method synthetic dimethyl carbonate reaction with above-mentioned preparation:

[0039] Application experiment 1:

[0040] (1) In the 500mL autoclave reactor that is equipped with distillation column, add 200mL anhydrous methanol, 14.85g urea, the ZnO catalyst that 2g embodiment 1 prepares;

[0041] (2) purging reaction system with nitrogen;

[0042] (3) The temperature is raised to 180° C. within 2 hours under stirring at 800 rpm, and the ammonia gas produced in the reaction is discharged from the top of the distillation column at any time;

[0043] (4) Cool down after reacting at 170...

Embodiment 2-5

[0047] Embodiment 2-5: (preparation of zinc oxide catalyst by thermal decomposition method)

[0048] Change the catalyst matrix, that is, use zinc acetate, zinc stearate, zinc sulfate or zinc chloride respectively as the catalyst matrix, and the others are the same as in Example 1.

[0049]Gained catalyst is evaluated under the conditions of application experiment 1, and its gained dimethyl carbonate yield is shown in Table 1.

[0050] Table 1 Catalytic properties of ZnO catalysts prepared from different parent salts

[0051] Catalyst precursor Calcination temperature, °C DMC yield, %

[0052] Zinc acetate 200 12.7

[0053] Zinc stearate 300 9.55

[0054] Zinc sulfate 850 5.36

Embodiment 6

[0055] Embodiment 6: (precipitation method prepares zinc oxide catalyst)

[0056] (1) Weigh the parent salt 40gZn(NO 3 ) 2 ·6H 2 O, dissolved in 200mL distilled water;

[0057] (2) Preparation of precipitant: weigh 16gNa 2 CO 3 , dissolved in 200mL distilled water;

[0058] (3) Quickly mix (1) and (2) and stir vigorously;

[0059] (4) After standing for 5 hours, filter, wash with water until neutral, and then replace the water with ethanol;

[0060] (5) vacuum drying constant weight;

[0061] (6) Calcining at 450° C. for 4 hours in a muffle furnace to prepare a zinc oxide catalyst.

[0062] The catalyst sample was tested by XRD, and the phase structure was hexagonal; the average diameter of the catalyst particles was 26.5nm as tested by TEM.

[0063] Application experiment 3:

[0064] Using the zinc oxide prepared in Example 6, the catalyst evaluation conditions were the same as those in Application Experiment 1, and the yield of dimethyl carbonate was 6.62%.

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Abstract

The metal oxide catalyst for urea alcoholysis process of synthesizing methyl carbonate consists of 1-3 kinds oxides of Li, Mg, Ni, Zn, Pb, Al, Fe, Mo, Zr and La, and has ZnO as main component accounting for 35-95 wt%. When it consists of three kinds of metal oxide, the other two except ZnO have the same weight percentage. It is prepared through thermal decomposition process, precipitation process, or coprecipitation process. The catalyst is easy to prepare, separate, recover and regenerate, and has high catalytic activity for urea alcoholysis process of synthesizing methyl carbonate, yield up to 49.7%, no corrosion of equipment and no environmental pollution.

Description

technical field [0001] The invention belongs to a metal oxide catalyst for dimethyl carbonate and a preparation method thereof, in particular to the oxides and the Mixtures thereof and methods for their preparation. technical background [0002] Dimethyl carbonate is an important organic chemical raw material, which can replace highly toxic phosgene, methyl chloride, and dimethyl sulfate for carbonylation, methylation, and methoxylation reactions, and can be used to synthesize a variety of organic chemicals And fine chemicals, can also be used as non-toxic solvents and high-performance oil additives. At present, the industrialized production methods of dimethyl carbonate include phosgene method, transesterification method and methanol oxidative carbonylation method, but they have disadvantages in safety, environmental protection, economy and technology, etc.: the raw materials of phosgene method are highly toxic, The by-product hydrochloric acid not only corrodes the equip...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/06C07C68/00
Inventor 王延吉赵新强邬长城
Owner HEBEI UNIV OF TECH
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