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Method for preparing P-isopropyl toluene from dipentene

A technology of isopropyl toluene and dipentene liquid, which is applied in the field of catalyzing the liquid-phase dehydrogenation of dipentene to prepare p-isopropyl toluene, which can solve the problems of high requirements for reaction equipment, expensive catalysts, and complicated pretreatment work , to achieve the effect of simplifying the pretreatment work, stable catalyst effect and good application prospect

Inactive Publication Date: 2005-03-23
GUANGZHOU INST OF GEOCHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although palladium-based catalyzed gas-phase dehydrogenation can obtain relatively satisfactory results, there are many disadvantages such as expensive catalysts, high requirements for reaction equipment (requires a gasification bed), and high reaction temperature. Therefore, high energy consumption during production and environmental fire protection are required. Explosion-proof
Foreign research mainly focuses on the gas-phase dehydrogenation of dipentene. Domestic studies have carried out a small amount of liquid-phase dehydrogenation. The catalysts involved in the published literature include solid acid and Raney nickel. Disadvantages such as the treatment method has a great influence on the catalytic effect

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Get 200g dipentene and join in the 500ml four-necked bottle that stirrer, spherical condenser, thermometer are equipped with, pass N 2 Protection, start the stirrer, add 0.5g of phosphotungstic acid to it, heat up, and finally the temperature of the reaction system is stabilized between 175-180°C, and reflux for 6 hours; then distill, the product contains 78.0% p-cymene.

Embodiment 2

[0017] Get 200g dipentene and join in the 500ml four-necked bottle that stirrer, spherical condenser, thermometer are equipped with, pass N 2 Protection, start the stirrer, add 0.2g of silicotungstic acid to it, heat up, and finally the temperature of the reaction system is stabilized between 175-180°C, and reflux for 8 hours; then distill, the product contains 70.8% p-cymene.

Embodiment 3

[0019] Get 200g dipentene and join in the 500ml four-necked bottle that stirrer, spherical condenser, thermometer are equipped with, pass N 2 Protection, start the agitator, add 0.02g of phosphomolybdic acid therein, heat up, and finally the temperature of the reaction system is stabilized between 175-180°C, and reflux for 12 hours; re-distillation, the product contains 74.0% p-cymene.

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PUM

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Abstract

The invention refers to a method for producing para isopropyl tolyl by catalyzing dipentylene liquid dehydrogenation. The method uses heteropoly acid as catalyst, the reaction is carried on in liquid phase and under the protection of inert gas, carries on heating and back flow reaction for 1-12hours. The price of the catalyst is low, the quantity is small and the temperature is low, the effect is stable.

Description

technical field [0001] The invention relates to a method for preparing p-isopropyltoluene by catalyzing liquid-phase dehydrogenation of dipentene. technical background [0002] my country has abundant turpentine resources. In the production process of synthesizing camphor and terpineol with turpentine as raw material, a large amount of by-product dipentene (main components are limonene, α-terpinene, γ-terpinene, Terpinolene). my country produces more than 3,000t of dipentene every year, which is currently mainly used as a solvent, and a small amount is exported, and there are no other industrial uses yet. [0003] Dipentene can be produced through catalytic dehydrogenation of p-cymene, which is an important organic intermediate that can synthesize a variety of spices, and can also be used to synthesize p-cresol and other fine chemical products, while p-toluene Phenol is an important organic chemical and fine chemical product. Therefore, if this research can be industrializ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C5/393C07C5/42C07C15/02
Inventor 哈成勇李佶辉
Owner GUANGZHOU INST OF GEOCHEMISTRY - CHINESE ACAD OF SCI