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Preparation technology for piperonal crystal

A preparation process, piperonal aldehyde technology, applied in the field of piperonal aldehyde crystallization preparation process, can solve the problems of hindered crystal growth, prone to wall sticking, small crystal particle size, etc., and achieve the effect of easy operation control, not easy to stick to wall, and not easy to agglomerate

Inactive Publication Date: 2015-08-12
HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among the two methods, the yield of piperonal produced by the cooling crystallization method is low, and the yield of piperonal obtained by elution crystallization is high, but the mother liquor is a mixture of water and ethanol, and ordinary rectification cannot obtain absolute ethanol, and recovery is difficult
The following problems exist in the current crystallization process: one, in the cooling crystallization process, after the solvent is determined, the crystallization process yield increases with the increase of crystallization liquid concentration
However, the increase in the concentration of the crystallization liquid will lead to a high concentration of solute molecules, and the space for free movement of molecules will become smaller, which will cause obstacles for solute molecules to enter the crystal lattice, and the crystal growth will be hindered, while the crystallization nucleation rate will increase rapidly, resulting in smaller crystal particle size. , difficult to dry
Second, the crystallization process of piperonal is prone to sticking to the wall, and the crystallization process is difficult to control, resulting in low yield, poor crystal habit of the product, and serious coalescence during production period, which brings serious inconvenience to use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Mix the crude piperonal and absolute ethanol at a mass ratio of 50:100 and put it into a crystallizer, add Tween 80 accounting for 2.0‰ of the solute mass fraction, raise the temperature to 30°C, keep warm and stir fully to dissolve it completely , add piperonal seed crystals accounting for 5‰ of the solute mass fraction at 3°C ​​before cooling down to the crystallization point, grow the crystals, and then carry out temperature-controlled cooling at a rate of (2n-1)°C / 10min (n is the temperature adjustment during the cooling process The number of times is a natural number greater than 1, and the temperature is controlled and adjusted once every 5 minutes). When the temperature drops to -10°C, stop cooling, and after growing the crystal for 1 hour, filter, wash, and dry to obtain the piperonal crystalline product.

Embodiment 2

[0022] The crude piperonal and absolute ethanol are mixed in a mass ratio of 78:100 and put into a crystallizer, and a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer (P 123 ), heat up to 40°C, keep warm and stir fully to make it completely dissolve, cool down to 1°C before the crystal out point, add piperonal aldehyde seed crystals accounting for 3‰ of the solute mass fraction, grow crystals, and then carry out temperature-controlled cooling, the cooling rate (2n)°C / 10min (n is the number of temperature adjustments in the cooling process, which is a natural number greater than 1, and the temperature is adjusted once every 20 minutes). When the temperature drops to -8°C, stop cooling, and after growing the crystal for 40 minutes, filter, Washing, drying to obtain piperonal crystalline product.

Embodiment 3

[0024] Put the crude piperonal and absolute ethanol into the crystallizer after mixing the mass ratio of 67:100, add polyoxyethylene-polyoxypropylene block copolymer (F 127 ), heat up to 35°C, keep warm and stir fully to make it completely dissolve, cool down to 5°C before the crystal out point, add piperonal aldehyde crystal seeds accounting for 2.5‰ of the solute mass fraction, grow crystals, and then carry out temperature-controlled cooling, the cooling rate 2(n+1)°C / 10min (n is the number of temperature adjustments in the cooling process, which is a natural number greater than 1, and the temperature is adjusted once every 8 minutes). When the temperature drops to -5°C, stop cooling and grow crystals after 0.5h , after filtering, washing and drying, the crystallized product of piperonal was obtained.

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Abstract

The invention belongs to the technical field of chemical crystallization, and particularly relates to a preparation technology for piperonal crystal. The preparation technology comprises the following specific processes: mixing a piperonal crude product with absolute ethyl alcohol in a ratio, and putting the mixture into a crystallizer; adding an appropriate crystal modifier, and heating for completely dissolving solid substances; carrying out temperature-control cooling crystallizing; adding piperonal seed crystal before inoculating the crystal, and cooling to a final temperature; and growing the grain, filtering, washing and drying to obtain a piperonal crystal product. According to the preparation technology provided by the invention, the wall sticking problem in a high-concentration crystallization process can be effectively avoided; the granularity of the prepared piperonal crystal product is greater than 1mm; the granularity distribution is uniform; the product is high in purity and high in yield; and the problem of agglomeration in the storage and transportation processes is effectively avoided.

Description

technical field [0001] The invention belongs to the technical field of chemical crystallization, and in particular relates to a process for preparing crystallization of piperonal. Background technique [0002] Piperonal (Heliotropine), the chemical name is 3,4-dioxymethylene benzaldehyde, the molecular formula is C 8 h 7 o 3 . Melting point 37°C, easily soluble in ethanol and ether, insoluble in glycerin and water. Piperonal is a white or light yellow crystal, which is easy to change color when exposed to light in the air. [0003] Piperonal is an important synthetic spice, which is widely used in daily cosmetic flavor, food flavor, spice processing, medicine, pesticide, electroplating and other industries. [0004] The crystallization process of piperonal mainly includes cooling crystallization method and dissolution crystallization method. The cooling crystallization method uses absolute ethanol as a solvent to form a supersaturated solution by lowering the temperatu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D317/54
CPCC07D317/54
Inventor 刘宝树孙华王亚川任凯王禄
Owner HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY
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