Process for stirring type multi-kettle continuous oxidation preparation of trimellitic anhydride

A technology of trimellitic anhydride and agitation, which is applied in the field of continuous oxidation to anhydride to produce trimellitic anhydride, can solve the problems of insufficient oxidation reaction, easy residual insoluble matter, easy short circuit, etc., and achieves faster reaction speed, stable process index and strong operability. Effect

Inactive Publication Date: 2005-07-06
天津大学北方化工新技术开发公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reactor for batch production of trimellitic anhydride needs to repeatedly increase and decrease the pressure and temperature, the equipment is prone to fatigue, the service life is shortened, and the production safety is reduced. At the same time, the output and yield are low, the quality is unstable, and it is difficult to form large-scale production
Chinese patent application CN 1401642 A discloses a "Method for Producing Trimellitic Anhydride by Continuous Oxidation Process". Although the production method involved in this application proposes to solve the problem of continuity of oxidation reaction, it must carry out innovative specific step design in the implementation process , such as the requirements for the number of oxidation and anhydride reaction devices, the requirements for the temperature and pressure parameters of the step-by-step reaction, and the connection between the various process steps, etc., it is possible to truly solve the problem of the continuity of trimellitic anhydride production
In the initial stage of the reaction, that is, during the generation of trimellitic acid and trimphthalic acid, the exothermic heat is very large, and the requirements for the reaction temperature can be carried out at a lower temperature, so cooling is used to remove the heat of reaction; The heat is less, in order to ensure the completion of the reaction process, the reaction temperature should be ma

Method used

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  • Process for stirring type multi-kettle continuous oxidation preparation of trimellitic anhydride
  • Process for stirring type multi-kettle continuous oxidation preparation of trimellitic anhydride
  • Process for stirring type multi-kettle continuous oxidation preparation of trimellitic anhydride

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Example Embodiment

[0021] Example 1:

[0022] 1000kg of trimethylbenzene is pumped into the metering tank, 5000kg of solvent acetic acid is pumped into another metering tank, the above two materials are sent into the batching tank to be mixed, and the accelerator tetrabromoethane, Catalyst cobalt acetate and manganese acetate 5.2kg each, heated to 50°C and fully stirred. After the catalyst was dissolved, the mixture was moved to the batching storage tank with a metering pump at 1M 3 The raw material mixed solution is pumped into the series-connected oxidation reaction kettle at the flow rate of / hour. Compressed air is fed into the first, second and third stage oxidation reactors in parallel at the same time, and its distribution ratio is according to the first stage: the second stage: the third stage = 0.6: 0.3: 0.1, and the temperature of the first stage oxidation reactor is 200 ℃±5℃, the temperature of the second-stage oxidation reactor is 210℃±5℃, the temperature of the third-stage oxidatio...

Example Embodiment

[0023] Example 2:

[0024] 1500kg of trimethylbenzene is pumped into the metering tank, 6000kg of acetic acid is pumped into another metering tank, the above-mentioned two materials are sent into the batching tank, and tetrabromoethane, cobalt acetate, manganese acetate 4.8kg are added to heat simultaneously. Stir to 50 ℃ until the catalyst is completely dissolved, stir evenly, and put it into the batching storage tank. Use metering pump to 1.5M 3 The flow rate per hour will drive the raw material mixture into the oxidation reactors connected in series, and the compressed air will be pressed into the first, second and third stage oxidation reactors in parallel at the same time, and its distribution ratio is 0.4:0.3:0.3. The temperature of the first-stage oxidation reaction kettle is 195°C±5°C; the second-stage oxidation reaction kettle is 205°C±5°C; the third-stage oxidation reaction kettle is 215°C±5°C, and the pressure is 2.1Mpa (absolute pressure), strictly controlled The...

Example Embodiment

[0025] Example 3:

[0026] 2000kg of trimethylbenzene and 11000kg of acetic acid were pumped into their respective measuring tanks, sent to the batching tank, and 8.5kg of cobalt acetate and manganese acetate were added, heated to 50 ° C, and transferred to the batching storage tank after stirring and dissolving. . The tetrabromoethane accelerator is separately divided into the second and third stage oxidation reactors in two separate times, 3.5kg and 5.0kg. Use metering pump to 1.8M 3 The flow rate per hour is injected into the three-stage oxidation reaction kettle in series, and the compressed air is pressed into each oxidation reaction kettle in parallel. It is 3.2Mpa (absolute pressure). The temperature of the first-stage oxidation reaction kettle is 200°C±5°C; the temperature of the second-stage oxidation reaction kettle is 210°C±5°C; the temperature of the third-stage oxidation reaction kettle is 220°C±5°C. Strictly control the oxygen content in the exhaust manifold ...

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Abstract

The invention relates to a process for stirring type multi-kettle continuous oxidation preparation of trimellitic anhydride with 1,2,3-trimethylbenzene as raw materials, acetic acid as solvent, tetrabromoethane as promoter, and cobalt acetate and manganese acetate as catalyst. Three and four stage cascade oxidation reaction kettles with stirring device are employed, the temperature of kettle is 160C.í½250C. with step type temperature rise among kettles, and pressure is 1.8í½3.2MPa (absolute pressure); Two and three stage cascade anhydride-forming reaction kettles with stirring device are employed with the temperature of kettle of 160C.í½250C. and pressure of 0.08MPaí½0.12Mpa (absolute pressure). Said materials are added separately in proportion in oxidation reaction kettle, and fed into multi-stage cascade reaction kettle with stirring device through pipeline connection by pump power, liquid phase continuous oxidation, anhydride-forming, purification are carried out with stirring to produce trimellitic anhydride. Miulti-kettle continuous production can prevent frequent operation of temperature and pressure control.

Description

technical field [0001] The invention relates to a method for producing trimellitic anhydride by continuous oxidation into anhydride, in particular to a method for producing trimellitic anhydride by continuous oxidation into anhydride in agitated multi-pots. Background technique [0002] Trimellitic anhydride is an important chemical raw material for modern new materials. It has high reactivity and can produce a series of valuable fine chemicals. It is mainly used in engineering plastics, high-quality plasticizers, heat-resistant insulating varnishes, advanced coatings and other industries. For example, it can be used in the production of PVC plasticizer trioctyl trimellitate, etc. [0003] At present, the domestic production methods of trimellitic anhydride are all produced by batch oxidation process, that is, trimellitic anhydride is produced in acetic acid solvent, with cobalt acetate, manganese acetate, tetrabromoethane or hydrogen bromide as catalyst, and compressed air ...

Claims

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Application Information

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IPC IPC(8): C07D307/89
Inventor 许长春陈维仁庞金铭卢宝铭杨汉斌马利群
Owner 天津大学北方化工新技术开发公司
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