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Method for preparing dibenzofuran

A technology of furan and diphenyl, which is applied in the field of chemical engineering and can solve the problems of large energy consumption, environmental pollution, unfavorable production cost and the like in industrialized production

Inactive Publication Date: 2012-09-12
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] At present, in the synthesis method of dibenzofuran, diphenyl ether or 2-cyclohexenyl cyclohexanone is mainly used as raw material to oxidize and synthesize under higher pressure and temperature, but this method consumes a lot of energy for industrial production, which is not conducive to production cost control
2,4,8-Trichlorodibenzofuran is a by-product in the new production process of trichlor, which is a kind of dioxin. The traditional treatment method is incineration, which pollutes the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] A certain amount of activated carbon powder is weighed and subjected to pickling, alkali washing, oxidation treatment and sodium nitrite anchoring treatment to obtain a catalyst carrier, which is then dried for later use.

[0022] Weigh 0.4422g of palladium chloride and 1.0239g of sodium nitrite with a purity of 59.5%, and fully dissolve it in a 50mL mixed solution of 1% dilute hydrochloric acid and methanol at a volume ratio of 1:1 and add it dropwise to 3g of the catalyst carrier In the aqueous solution, immerse for 8 hours, add 10 mL of 37% formaldehyde and 1 mL of 80% hydrazine hydrate and reduce for 6 hours at 50 ° C, after cooling, filter, wash, dry and cool to obtain a Pd / C catalyst with a loading capacity of 5%.

[0023] A tank reactor was loaded with 0.5 g of 5% Pd / C catalyst, 1.0 g of trioctylmethylammonium chloride, 5.0 g of 2,4,8-trichlorodibenzofuran, 30 mL of toluene and 15% aqueous NaOH 25mL, hydrogen gas flow rate 100mL / min, normal pressure, 100°C for 6....

Embodiment 2

[0025] A certain amount of diatomite is weighed, acid-washed, alkali-washed, oxidized, and potassium nitrite anchored to obtain a catalyst carrier, and then dried for use.

[0026] Take by weighing 0.9336g purity and be 59.5% palladium chloride and 0.2663g potassium nitrite, and after fully dissolving it in 50mL mixed solution of 3% dilute hydrochloric acid and methanol by volume ratio 1:5, add dropwise to 3g catalyst carrier In the aqueous solution, immerse for 12 hours, add 20mL of 27% formaldehyde and 1mL of 50% hydrazine hydrate, reduce at 100°C for 3 hours, filter, wash, dry and cool after cooling to obtain a Pd / diatomite catalyst with a loading capacity of 10%.

[0027] 1.0 g of 10% Pd / diatomaceous earth catalyst, 0.35 g of benzyltriethylammonium chloride, 5.0 g of 2,4,8-trichlorodibenzofuran, 85 mL of p-xylene and 50mL of 10% KOH aqueous solution, hydrogen gas flow rate of 70mL / min, normal pressure, 80°C for 0.5h, and dibenzofuran was obtained by conventional separation...

Embodiment 3

[0029] A certain amount of diatomite powder is weighed and subjected to pickling, alkali washing, oxidation treatment and potassium nitrite anchoring treatment to obtain a catalyst carrier, which is dried for use.

[0030] Weigh 0.0695g of platinum chloride with a purity of 59.5% and 0.0660g of potassium nitrite, fully dissolve them in 50mL mixed solution of 5% dilute hydrochloric acid and methanol at a volume ratio of 1:3, and add them dropwise to 3g of catalyst carrier In the aqueous solution of immersion for 16 hours, add 15mL of 10% formaldehyde and 1mL of 60% hydrazine hydrate to reduce at 75°C for 6 hours, after cooling, filter, wash, dry and cool to obtain a Pt / diatomaceous earth catalyst with a loading capacity of 1%.

[0031]A kettle reactor was loaded with 0.35 g of 1% Pt / Celite catalyst, 0.6 g of tetrabutylammonium chloride, 5 g of 2,4,8-trichlorodibenzofuran, 50 mL of ethylbenzene and 40 mL of 5% aqueous NaOH , hydrogen feed rate 10mL / min, normal pressure, 40 ° C u...

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Abstract

The invention relates to a method for preparing dibenzofuran. The method comprises the following steps of: performing hydrodechlorination on 2,4,8-trichlorodibenzofuran in a kettle reactor at a certain temperature under the normal pressure to obtain dibenzofuran; and reacting by taking aromatic hydrocarbon as a solvent and adding sufficient alkali solution and a phase transfer catalyst under the action of a noble metal loaded catalyst under the condition that the reaction temperature is 40-100 DEG C and the hydrogen flow rate is 10-100 mL / min for 0.5-6 hours to synthesize dibenzofuran. The transformation ratio of 2,4,8-trichlorodibenzofuran is 99.96 percent, and the yield of dibenzofuran is 99.57 percent.

Description

technical field [0001] The invention relates to a method for preparing dibenzofuran by hydrodechlorination of 2,4,8-trichlorodibenzofuran under normal pressure and lower temperature conditions in a tank reactor, belonging to the technical field of chemical engineering . Background technique [0002] Dibenzofuran is an excellent high-boiling point organic solvent, which can dissolve a variety of polymer compounds, and can also be used as raw materials for medicine, disinfectants, preservatives, fuels, synthetic resins and high-temperature lubricants, such as dibenzofuran Some of the derivatives have anti-inflammatory, analgesic, muscle-relaxing and vasodilation activities. In addition, dibenzofuran can also form a eutectic mixture with biphenyl as a heat transfer solvent. [0003] In the patent of US 4009185A, diphenyl ether is used as the reaction raw material, and cerium is loaded on different supports as catalysts, and dibenzofuran is continuously oxidized on a fixed bed...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/91
Inventor 程福昌张维祥周志伟武文良秦娟王巍张扬
Owner NANJING UNIV OF TECH
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