A kind of piperonal crystal preparation process

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...

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