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The preparation method of 2,5-diphenyloxazole

A technology of diphenyloxazole and benzamidoacetic acid, which is applied in the field of preparation of 2,5-diphenyloxazole, can solve the problems of high energy consumption, harsh conditions, and large pollution, and achieve simplified operation process, Improve production efficiency and reduce environmental pollution

Active Publication Date: 2016-08-24
HAISO TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The yield of the target product prepared by this method is low, the total yield is 39.8%, and the conditions are harsh and the pollution is large. Especially in the bromination process, bromine is used, which is highly toxic and corrosive, and the reaction time is long and the energy consumption is high.
The product obtained by this method and the products sold on the market cannot meet the requirements of the pure grade of scintillation

Method used

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  • The preparation method of 2,5-diphenyloxazole
  • The preparation method of 2,5-diphenyloxazole
  • The preparation method of 2,5-diphenyloxazole

Examples

Experimental program
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Embodiment 1

[0027] Add benzamidoacetic acid (II) (179kg, 1kmol) and thionyl chloride (238kg, 2kmol) into a 5000L enamel reactor with mechanical stirring and a thermometer, react at 50°C, and take samples to monitor until the compound (II ) complete the reaction, distill unreacted thionyl chloride to obtain benzamidoacetyl chloride (Ⅲ), cool down to 50°C, add benzene (780kg, 10kmol) and aluminum trichloride (267kg, 2kmol), heated to reflux for 3 hours, the resulting N-benzoyl-ω-aminoacetophenone (IV) reaction solution was cooled to 30°C, added 50wt% sulfuric acid (392kg, 2kmol), slowly warmed up to 100°C, at this temperature After the reaction was completed, excess benzene was evaporated, the temperature of the reaction solution was lowered to 30°C, water (1568kg) was added dropwise into the reactor, and a white solid was precipitated, filtered and rectified to obtain 2,5-diphenyloxazole (I ) is about 202kg, the yield is 91.4%, and the content is 99.3% (HPLC). The analysis and detection ca...

Embodiment 2

[0030] Other steps are identical with embodiment 1, just gained 2,5-diphenyloxazole purification method is as follows:

[0031] Obtain 2,5-diphenyloxazole (150kg) according to the synthetic method of embodiment 1, drop in 1000L stainless steel reactor, add toluene (600kg), iron oxide powder (3kg), gac (1.5kg), stir , turn on the steam heating, stir at 110°C for 3 hours, cool down to 25°C, filter the filter tank to remove the solid, then filter through a microporous filter (0.5 μm in pore size), and evaporate the toluene solvent to obtain 2,5-diphenyl Base oxazole 145kg, purification yield 96.7%, content 99.8% (HPLC), melting point: 72.3-73.5°C, analysis and detection meet the requirements of fluorescent scintillator, can be used as organic scintillator.

Embodiment 3

[0033] Purification experiments were carried out in the same manner as in Example 2, except that nickel oxide powder (3kg) was added instead of iron oxide powder, and xylene was used instead of toluene to obtain 145.3kg of 2,5-diphenyloxazole with a purification yield of 96.9 %, the content is 99.8% (HPLC), the melting point is 72.2-73.5°C, the analysis and detection meet the requirements of fluorescent scintillator, and can be used as organic scintillator.

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Abstract

The invention relates to a method for preparing scintillation pure grade 2,5-diphenyl oxazole (DPO or PPO for short). The method comprises the following steps: by taking benzoyl glycine as a raw material, performing multiple steps of reaction such as acylating chlorination, Frieldel-Crafts and ring formation, purifying middle products of each step without being separated, and preparing 2,5-diphenyl oxazole by using a one-pot method. An obtained product can be rectified and purified, the requirements of a scintillator cannot be met but metal oxide heating treatment is needed, and thus a 2,5-diphenyl oxazole product for scintillation fluor can be obtained. As the one-pot method is adopted to prepare 2,5-diphenyl oxazole, the reaction steps are reduced, the operation process is simplified, the production efficiency is improved, a purification method is simple, convenient and effective, and on-scale industrialization production is achieved.

Description

technical field [0001] The invention relates to the field of fine chemical industry, in particular to a method for preparing scintillation pure grade 2,5-diphenyloxazole (DPO or PPO). Background technique [0002] Organic scintillator is an extremely important test material in national defense scientific research. Under the excitation of high-energy electromagnetic radiation, it can emit short-term fluorescence, which is amplified by a photomultiplier tube and causes a voltage pulse on the anode, which is transmitted through a retort. into the recorder to record. Scintillation counters and scintillation spectrometers are devices that use this principle to work. Organic scintillator is an indispensable working substance in scintillation counters. Liquid scintillation counting technology is a new measurement technology that has only been developed in the world for more than 30 years. It has been increasingly used in various scientific fields. [0003] As a kind of organic sc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D263/32
CPCC07D263/32
Inventor 李翔刘小成邓嘉伦胡丽蔡光威李自勇张荔英
Owner HAISO TECH
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