Preparation method and crystallization method of 2, 3, 5-tri-methyl hydroquinone diester new crystal

A trimethylhydroquinone diester and crystal technology, which is applied in the preparation of carboxylic acid esters, chemical instruments and methods, and the preparation of organic compounds, to achieve the effects of high bulk density, high crystallinity, and simple and easy-to-control operating conditions

Active Publication Date: 2014-01-15
TIANJIN UNIV
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above crystallization method is difficult to simultaneously optimize the two indicators of "purity" and "yield"

Method used

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  • Preparation method and crystallization method of 2, 3, 5-tri-methyl hydroquinone diester new crystal
  • Preparation method and crystallization method of 2, 3, 5-tri-methyl hydroquinone diester new crystal
  • Preparation method and crystallization method of 2, 3, 5-tri-methyl hydroquinone diester new crystal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Add 50g of 2,3,5-trimethylhydroquinone diester solid with a purity of 99.5% into 50ml of methanol, heat up to 60°C to dissolve completely, then cool the solution to 40°C, and add dropwise under stirring Add 100ml of water at 40°C for 1 hour, continue stirring for 1 hour, vacuum filter and separate the resulting suspension, and dry the obtained filter cake at 40°C under a vacuum of 0.08 MPa to obtain colorless sticks 2,3, 47.47 g of 5-trimethylhydroquinone diester type B crystals were analyzed by gas chromatography. The purity was 99.8%, and the yield of 2,3,5-trimethylhydroquinone diester was 95.23%. The product has high crystallinity, large crystal particle size, smooth surface and high bulk density. The scanning electron microscope photos of the products are as follows: Figure 5 shown.

[0029] The PXRD spectrum of the product has characteristic peaks at diffraction angles 2θ=12.7, 13.8, 14.9, 15.7, 17.7, 18.7, 20.2, 20.4, 23.2, 24.0, 25.9, 27.2, 32.6, 33.5, 34.7, ...

Embodiment 2

[0031] Add 50g of 2,3,5-trimethylhydroquinone diester solid with a purity of 99.5% into 100ml of ethanol, heat up to 70°C to dissolve completely, then cool the solution to 30°C, and add dropwise under stirring 150ml of cyclohexane at a temperature of 30°C was added dropwise for 2h, and the stirring was continued for 2h. The resulting suspension was vacuum filtered and separated, and the resulting filter cake was dried at 50°C and a vacuum of 0.09MPa to obtain a colorless stick 2. 47.20 g of 3,5-trimethylhydroquinone diester type B crystals, its purity by gas chromatography analysis was 99.9%, and the yield of 2,3,5-trimethylhydroquinone diester was 94.78%. The product has high crystallinity, large crystal particle size and uniform particle size distribution.

[0032]The PXRD spectrum of the product has characteristic peaks at diffraction angles 2θ=12.6, 13.8, 14.9, 15.8, 17.7, 18.7, 20.3, 20.5, 23.2, 24.0, 25.9, 27.2, 32.5, 33.5, 34.7, 36.6, 40.7 and 42.5 degrees; DSC has a m...

Embodiment 3

[0034] Add 75g of 2,3,5-trimethylhydroquinone diester solid with a purity of 99.0% into 50ml of n-propanol, heat up to 80°C to dissolve completely, then cool the solution to 35°C, and stir Add 100ml of n-hexane at 35°C dropwise, add dropwise for 3h, continue stirring for 1h, vacuum filter and separate the resulting suspension, dry the resulting filter cake at 60°C and a vacuum of 0.1MPa to obtain a colorless stick 2 , 69.94 g of 3,5-trimethylhydroquinone diester type B crystals, its purity by gas chromatography analysis was 99.4%, and the yield of 2,3,5-trimethylhydroquinone diester was 93.63%. The product has high crystallinity, large crystal particle size and uniform particle size distribution.

[0035] The PXRD spectrum of the product has characteristic peaks at diffraction angles 2θ=12.5, 13.7, 14.9, 15.6, 17.8, 18.7, 20.2, 20.4, 23.2, 24.0, 25.9, 27.3, 32.6, 33.5, 34.7, 36.6, 40.7 and 42.5 degrees; DSC has a melting endothermic peak at 110.34°C; thermogravimetric analysi...

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Abstract

The invention relates to a preparation method and a crystallization method of a 2, 3, 5-trimethylhydroquinone diacetate new crystal. The crystal is defined as a type-B crystal by using a powder X ray diffraction atlas, a differential scanning calorimetric curve characteristic endothermic peak, a thermo-gravimetric analysis curve and an infrared light spectrum. The preparation method comprises the following steps: dissolving 2, 3, 5-trimethylhydroquinone diacetate of which the purity is larger than or equal to 97 percent into a C1-C3 low-molecular weight organic solvent to form solution, wherein the temperature is 50-80 DEG C, and the concentration of the 2, 3, 5-trimethylhydroquinone diacetate in the organic solvent is 0.5-2.5 g / ml; cooling the solution to 30-40 DEG C; dropwise adding a melting-out agent of which the volume is 1-5 times of that of the organic solvent into a suspension; continuously agitating for 0.5-2 hours after the completion of dropwise adding; and separating an obtained solid-liquid suspension and vacuum-drying to obtain the 2, 3, 5-tri-methyl hydroquinone diester type-B crystal. The PXRD (Powder X Ray Diffraction) atlas and a SEM (Scanning Electron Microscope) picture can confirm that the degree of crystallinity of a product is high, the crystal is good in crystal habit, larger in grain size, smooth in crystal surface and higher in bulk density, the subsequent operation is facilitated in the crystallization process, and meanwhile, the quality of a 2, 3, 5-trimethylhydroquinone diacetate product is effectively improved.

Description

field of invention [0001] The invention belongs to the technical field of chemical engineering crystallization, and particularly relates to a crystallization method for preparing a new crystal form of 2,3,5-trimethylhydroquinone diester and improving product quality. Background of the invention [0002] 2,3,5-trimethylhydroquinone diester, full name 2,3,5-trimethylhydroquinone diacetate, English name trimethylhydroquinone diacetate, also known as 1,4-diacetoxy-2,3, 5-trimethylbenzene, the molecular formula is C 13 h 16 0 4 , with a molar mass of 236.268g·mol -1 , the structural formula is as follows: [0003] [0004] 2,3,5-Trimethylhydroquinone diester is a synthetic vitamin E (V E ) is an important intermediate in the synthesis of pharmaceutically active chroman compounds, and is widely used as an antioxidant. V E It is widely used in medicine, food, health products, cosmetics, animal husbandry and other fields. V E It has become the main vitamin variety with a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/16C07C67/52
Inventor 尹秋响杨利强侯宝红王静康张美景龚俊波王永莉鲍颖王召谢闯
Owner TIANJIN UNIV
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