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Preparation method of pyromellitic dianhydride based on modified vanadium-titanium oxide composite catalysis

A technology of pyromellitic dianhydride and vanadium titanium oxide, which is applied in the field of preparation of pyromellitic dianhydride, and achieves the effects of low energy consumption, mild reaction conditions and excellent thermal stability

Inactive Publication Date: 2019-02-15
PENG CHEN NEW MATERIALS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the purity and yield of the product need to be further improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A method for preparing pyromellitic dianhydride based on modified vanadium-titanium oxide composite catalysis, comprising the following steps:

[0024] (1) sodium metavanadate is dissolved in water to obtain sodium metavanadate solution; tetrabutyl titanate is dissolved in bromobutane to obtain tetrabutyl titanate solution;

[0025] (2) Transfer the prepared sodium metavanadate solution to a flask with a condenser and a stirrer, and simultaneously add tetrabutyl titanate solution and ammonia solution dropwise to the flask, after the dropwise addition, heat up to 100 Stir and react at -120°C and 1500 rpm for 10 hours. After the reaction, cool down to 60-70°C, continue to add N-methylimidazole, and continue the reaction for 10 hours. After the reaction, cool to room temperature, filter, wash and dry the solid; A catalyst precursor is prepared; wherein, the molar ratio of sodium metavanadate, tetrabutyl titanate, and N-methylimidazole is 1:1:0.04;

[0026] (3) Redisperse ...

Embodiment 2

[0029] A method for preparing pyromellitic dianhydride based on modified vanadium-titanium oxide composite catalysis, comprising the following steps:

[0030] (1) sodium metavanadate is dissolved in water to obtain sodium metavanadate solution; tetrabutyl titanate is dissolved in bromobutane to obtain tetrabutyl titanate solution;

[0031] (2) Transfer the prepared sodium metavanadate solution to a flask with a condenser and a stirrer, and simultaneously add tetrabutyl titanate solution and ammonia solution dropwise to the flask, after the dropwise addition, heat up to 100 Stir and react at -120°C and 5500 rpm for 15 hours. After the reaction, cool down to 60-70°C, continue to add N-methylimidazole, and continue the reaction for 20 hours. After the reaction, cool to room temperature, filter, wash and dry the solid; A catalyst precursor is prepared; wherein, the molar ratio of sodium metavanadate, tetrabutyl titanate, and N-methylimidazole is 1:1:0.1;

[0032] (3) Redisperse t...

Embodiment 3

[0035] A method for preparing pyromellitic dianhydride based on modified vanadium-titanium oxide composite catalysis, comprising the following steps:

[0036] (1) sodium metavanadate is dissolved in water to obtain sodium metavanadate solution; tetrabutyl titanate is dissolved in bromobutane to obtain tetrabutyl titanate solution;

[0037](2) Transfer the prepared sodium metavanadate solution to a flask with a condenser and a stirrer, and simultaneously add tetrabutyl titanate solution and ammonia solution dropwise to the flask, after the dropwise addition, heat up to 100 Stir and react at -120°C at 2000 rpm for 11 hours, cool down to 60-70°C after the reaction, continue to add N-methylimidazole, continue the reaction for 12 hours, cool to room temperature after the reaction, filter, wash and dry the solid; A catalyst precursor is prepared; wherein, the molar ratio of sodium metavanadate, tetrabutyl titanate, and N-methylimidazole is 1:1:0.06;

[0038] (3) Redisperse the cata...

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PUM

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Abstract

The invention discloses a preparation method of pyromellitic dianhydride based on modified vanadium-titanium oxide composite catalysis. The method comprises the steps of firstly, preparing a modifiedvanadium-titanium oxide composite catalyst from sodium metavanadate and tetrabutyl titanate as raw materials by in-situ modification, melting tetramethylbenzene as a raw material by heating, filteringand introducing into a measuring tank, introducing steam to an inner coil to preserve the heat to 100-105 DEG C, filtering with a filter screen and pumping into a vaporization mixer; preheating the air to 190-200 DEG C, and then introducing the air to the vaporization mixer; reacting the preheated air with the tetramethylbenzene under the catalysis of the composite catalyst prepared above, and cooling the gas generated by the reaction through a heat exchange to obtain crude pyromellitic dianhydride; and then recrystallizing the crude pyromellitic dianhydride with acetone to obtain pyromellitic dianhydride. The method is high in reaction speed and product yield.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for preparing pyromellitic dianhydride based on composite catalysis of modified vanadium-titanium oxide. Background technique [0002] Pyromellitic dianhydride is also called 2,4,5-pyromellitic anhydride, and its molecular formula is C 10 H2O 6 , with a molecular weight of 218.1193, this substance is mainly used in the production of polyimide resins, high temperature resistant electrical insulating varnishes, PVC plasticizers, synthetic resin crosslinking agents and epoxy resin curing agents, and is also used in the production of phthalocyanine blue dyes. [0003] In 1851, Erdman OL discovered homoanhydride during the pyrolysis of mellitic acid. In 1947, California Research Corp. of the United States produced homoanhydride for the first time by using durene as raw material to catalyze gas-phase catalytic oxidation of vanadium pentoxide composite oxide. At present, this...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D493/04B01J23/22
CPCB01J23/002B01J23/22C07D493/04
Inventor 谈勇谈俊江晓龙陈亮乔久昌
Owner PENG CHEN NEW MATERIALS TECH CO LTD
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