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Method for preparing terephthalaldehyde through catalytic oxidation

A technology for terephthalaldehyde and catalytic oxidation, which is applied in the directions of oxidative preparation of carbonyl compounds, chemical instruments and methods, halogenated hydrocarbon preparation, etc. Increased overall yield, increased conversion, elimination of hazard effects

Inactive Publication Date: 2014-01-15
LIANYUNGANG HUALUN CHEM
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0003] At present, the industry is mainly obtained by chlorination and hydrolysis of p-xylene. Its production industry uses highly toxic chlorine gas, and produces highly corrosive hydrogen chloride gas, which will pollute the environment while corroding the reactor, and will generate a variety of chlorinated intermediates. Terephthalaldehyde yield decreased
Liu Yanbing's master's thesis (Preparation, Characterization and Catalytic Oxidation of p-Xylene on Fe-Mo-Ni Catalyst. Guangxi University) reported that the partial oxidation of p-xylene to prepare terephthalaldehyde is an environmentally friendly green process, in which Ni The Fe-Mo catalyst is modified, and the modified catalyst can significantly improve the conversion rate of p-xylene and the selectivity of terephthalaldehyde, but the above method is only suitable for small-scale laboratory production due to the complicated preparation of the catalyst and the high price. Not suitable for industrial mass production

Method used

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  • Method for preparing terephthalaldehyde through catalytic oxidation
  • Method for preparing terephthalaldehyde through catalytic oxidation

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Dissolve 10.6g p-xylene in 200mL solvent acetonitrile and add it to the reaction kettle, and add 3.15g fluorine reagent N-fluorobisbenzenesulfonamide and 5.8g sodium chloride to it, and react at room temperature to obtain a mixture of p-dichlorobenzene Add 98wt% sulfuric acid (1:2 volume ratio to p-xylene) and 8.69g manganese dioxide to the mixed solution without treatment, heat it at room temperature to reflux temperature, and react for 5-7 hours; after the reaction, the mixed solution is cooled and filtered , the filtrate was adjusted to pH 6~7 with NaOH solution, washed with water to separate the organic layer, and the organic layer was distilled under reduced pressure to obtain the crude terephthalaldehyde, which was recrystallized with 100 mL of ethanol and water mixed solution with a volume ratio of 1:1, and dried Finally, 8.65 g of terephthalaldehyde was obtained, with a yield of 64.5%.

[0025]

Embodiment 2

[0027] Dissolve 10.6g p-xylene in 200mL solvent acetonitrile and add it to the reaction kettle, and add 15.75g fluorine reagent N-fluorobisbenzenesulfonamide and 5.8g sodium chloride to it, and react at room temperature to obtain a mixture of p-dichlorobenzene Add 98wt% sulfuric acid (1:4 volume ratio to p-xylene) and 8.69g manganese dioxide to the mixed solution without treatment, heat it at room temperature to reflux temperature, and react for 5-7 hours; after the reaction, the mixed solution is cooled and filtered , the filtrate was adjusted to pH 6~7 with NaOH solution, washed with water to separate the organic layer, and the organic layer was distilled under reduced pressure to obtain the crude terephthalaldehyde, which was recrystallized with 100 mL of ethanol and water mixed solution with a volume ratio of 1:1, and dried Finally, 10.36 g of terephthalaldehyde was obtained with a yield of 77.3%.

[0028]

Embodiment 3

[0030] Dissolve 21.2g of p-xylene in 400mL of solvent acetonitrile and add it to the reaction kettle, and add 25.52g of fluorine reagent N-fluorobisbenzenesulfonamide and 11.6g of sodium chloride to it, and react at room temperature to obtain a mixture of p-dichlorobenzene Add 98wt% sulfuric acid (1:4 volume ratio to p-xylene) and 17.38g manganese dioxide to the mixed solution without treatment, heat it at room temperature to reflux temperature, and react for 5-7 hours; after the reaction, the mixed solution is cooled and filtered , the filtrate was adjusted to pH 6~7 with NaOH solution, washed with water to separate the organic layer, and the organic layer was distilled under reduced pressure to obtain the crude terephthalaldehyde, which was recrystallized with 100 mL of ethanol and water mixed solution with a volume ratio of 1:1, and dried Finally, 20.7 g of terephthalaldehyde was obtained with a yield of 77.2%.

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Abstract

The invention discloses a method for preparing terephthalaldehyde through catalytic oxidation. The method is characterized in that a fluorination agent is adopted to catalyze sodium chloride so as to obtain the only product of p-dichloro benzene, and the selectivity of the p-dichloro benzene to a product is improved, so that the total yield is improved greatly; the p-dichloro benzene is oxidized to obtain the terephthalaldehyde, manganese dioxide is used as an oxidation agent, and 98 wt% of sulfuric acid is added, so that the catalytic oxidation effect is enhanced, and the conversion rate of the p-dichloro benzene is increased; all used raw materials are environment-friendly and cheap and are easy-to-get industrial products, so that the hazard of chlorine gas chloridization for the traditional industry can be eliminated.

Description

technical field [0001] The invention relates to a method for preparing terephthalaldehyde, in particular to a method for preparing terephthalaldehyde by catalytic oxidation. Background technique [0002] The application and promotion of terephthalaldehyde in China and the experimental research of industrial production have gone through more than 20 years. In recent years, with the expansion of its application scope and the increase of its usage, it has become a fine product with great market potential and strong vitality. It is a variety of chemical products and is an important intermediate for the preparation of medicines, spices, dyes, plastics, and fluorescent whitening agents. Its series of products such as dichlorobenzyl and aldehyde acid have also become industrial varieties with a certain scale. [0003] At present, the industry is mainly obtained by chlorination and hydrolysis of p-xylene. Its production industry uses highly toxic chlorine gas, and produces highly c...

Claims

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Application Information

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IPC IPC(8): C07C45/27C07C47/544C07C22/04C07C17/14
CPCC07C45/27C07C17/361C07C47/544C07C25/08
Inventor 刘冰徐铭
Owner LIANYUNGANG HUALUN CHEM
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