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Continuous production method and device utilizing dipentene to prepare p-cymene

A p-cymene and production method technology, applied in the field of continuous production of p-cymene prepared from dipentene, can solve the problems of poor product quality stability, cumbersome production operation process, and difficulty in ensuring the quality of finished products, and achieve stable product quality , improve the unstable state, and reduce the effect of human operation deviation

Inactive Publication Date: 2012-09-26
CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (1) Problems with the batch reaction production process: the batch reaction production process is to place dipentene in a batch dehydrogenation reactor for reaction, and after the raw materials and catalysts are put into the reactor in proportion, then the temperature is raised under the stirring of the stirrer. Reaction, after several hours of reaction, after the sampling test is qualified, the machine can be shut down and the material can be discharged, and the catalyst can be removed by filtration to obtain the product. The separated catalyst needs to be replaced after repeated use for 3 to 10 times. The service life is short, the recycling times are many, and the catalyst is consumed in large quantities. The stability of product quality is poor, and the production scale is difficult to expand
[0005] (2) Problems existing in the continuous fixed bed production process: First, the catalyst used has a short service life, the longest being only about 3 months, which makes the production operation process cumbersome and the production cost is high; the second is the use of a single During the production of fixed-bed reactors, it is often necessary to control the high reaction temperature in the fixed-bed reactor. Long-term high temperature will shorten the life of the catalyst loaded in the reactor.
[0006] (3) It is necessary to solve the problem of computer automation control in the whole production process, otherwise it is difficult to guarantee the quality of the finished product

Method used

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Effect test

Embodiment 1

[0030] Embodiment 1 is the embodiment of the cymene continuous production device of the present invention

[0031] see figure 1 The schematic diagram of the embodiment of the relevant device of the continuous production method of p-cymene based on dipentene in the present invention, in this embodiment, by raw material storage tank 1, feeding pump 2, flowmeter 2, preheater 4 , fixed bed reactor Ⅰ5, fixed bed reactor Ⅱ6, fixed bed reactor Ⅲ7, cooler 8, and product storage tank 9. The outlet of raw material storage tank 1 is connected to the inlet of feeding pump 2, and the outlet of feeding pump 2 is connected to the inlet of flowmeter 3. The outlet of flowmeter 3 is connected to the inlet of preheater 4, the outlet of preheater 4 is connected to the upper inlet of fixed bed reactor I5, the lower outlet of fixed bed reactor I5 is connected to the upper inlet of fixed bed reactor II6, and the fixed bed reaction The lower outlet of device II6 is connected to the upper inlet of fi...

Embodiment 2

[0033] Example 2 Operation steps of the continuous production method for preparing p-cymene from dipentene

[0034] Put the catalyst into fixed bed reactor I5, fixed bed reactor II6 and fixed bed reactor III7 respectively, feed nitrogen, open the heating jacket of the three fixed bed reactors, and preheat the fixed bed reactor I5 to 180 ℃, the fixed-bed reactor II6 was preheated to 190°C, and the fixed-bed reactor III7 was preheated to 220°C; the raw material dipentene stored in the raw material storage tank 1 was 3 The flow rate per hour is sent to the preheater 4, the dipentene is preheated to 170°C, sent to the inlet of the fixed bed reactor I5, and flows through the fixed bed reactor II6 and the fixed bed reactor III7 in sequence, For dehydrogenation reaction, the material from the outlet of fixed bed reactor III 7 is the material after dehydrogenation reaction is completed.

[0035] The operating conditions of the dehydrogenation reaction are: the flow rate of dipentene ...

Embodiment 3~6

[0041] Control of dehydrogenation reaction conditions: set the amount of catalyst added to the three fixed-bed reactors to be 500kg, 1000kg, 1500kg, 2000kg, and 2500kg respectively, and the dipentene preheating temperature is 170°C~180°C; The pentene flow rate is 0.1 m3 / h, 0.2 m3 / h, 0.3 m3 / h, 0.4 m3 / h, 0.5 m3 / h, the reaction pressure of the fixed bed device is 0.01Mpa, 1 Mpa, 3 Mpa, 4Mpa, 5Mpa, the fixed bed Reactor Ⅰ reaction temperature is 170°C, 175°C, 180°C, 185°C, 190°C, fixed bed reactor Ⅱ reaction temperature is 190°C, 195°C, 200°C, 210°C, 220°C, fixed bed reactor Ⅲ reaction The temperature is 220°C, 230°C, 240°C, 250°C, 260°C.

[0042] When the reaction conditions were stable, the relative mass fractions of p-cymene in the dehydrogenation products were sampled and analyzed to be 69.3%, 77.2%, 81.1%, 75.3%, 71.8%, and 62.5%, respectively.

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Abstract

The invention provides a continuous production method and a device utilizing dipentene to prepare p-cymene. The method comprises the following steps: firstly, filling a catalyst in a fixed bed reactor, filling nitrogen, preheating dipentene by a preheater and then feeding dipentene into the fixed bed reactor to conduct dehydrogenation reaction; and colling and distilling materials subjected to dehydrogenation reaction so as to obtain a high-purity product. The invention also discloses a device, which utilizes the method and the structure that the production process including three fixed bed reactors connected in series instead of one fixed bed reactor in the prior art is adopted, the unstable state during the dehydrogenation reaction is improved, the production efficiency is improved, and the service life of the catalyst is prolonged; and meanwhile, automatic control is conveniently adopted in the production process, the product quality is stable, the purposes of safety, high efficiency and low consumption are achieved, the production scale is easy to enlarge.

Description

technical field [0001] The invention relates to a continuous production method for preparing p-cymene from dipentene and a related device which can effectively utilize the method for continuous production of p-cymene. Background technique [0002] Dipentene is a kind of monocyclic terpene by-product (including p-mentene, terpinene, p-cymene, etc., collectively referred to as dipentene) when camphor and terpineol are synthesized from forestry products turpentine. Most of pentene is used as paint solvent and its value is not high. Therefore, how to develop and utilize dipentene to make more valuable products is a major issue. Catalytic hydrogenation of dipentene to make p-cymene, and then use it as spice intermediate, pesticide intermediate or process other products, can increase the added value of turpentine processed products. [0003] Industrial dipentene catalytic dehydrogenation synthesis of p-cymene usually has a gas-phase method and a liquid-phase method. The gas-pha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/02C07C5/367C07C13/18C07C5/52
Inventor 黎继烈
Owner CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY