Starting Material Synthesis And Crystal Growth Of The Crystals. Dast

In this paper, the synthesis and purification of DAST (4-dimethylamino-N-methyl-4-stilbazolium tosylate) raw materials were introduced, the technology factor during the process were obtained. The crystal growth and surface morphology were analyzed in detail, the influence of different growth methods on DAST crystal shape was compared and summarized.DAST raw materials were synthesized and purified by means of a relatively simple method designed by ourselves in our laboratory, the cost of raw materials was cut down, since they were difficult to purchase and very expensive. The fourier transform infrared (FTIR) spectrum and nuclear magnetic resonance (NMR) were used to check the functional groups and molecular structure of raw materials, respectively. It was found that no extra functional groups and modes existed in the compound. It could be early proved that the product was DAST compound. DAST crystals were grown from the methanol solution with the synthesized raw materials by slow cooling method. The crystal structure was characterized by x-ray diffraction (XRD) method, the result showed that the structure of crystals was the same as that of DAST in the reference published before. It was showed that the quality of prepared raw materials could meet the requirements of crystal growth.DAST crystals have been grown by the slow cooling method and the evaporation method, respectively. The morphology of crystal surfaces was observed by the microscope and scanning electron microscope (SEM). Different growth striations were found on the growth surfaces. The arrangements of crystal ion groups and cooling rate had a great influence on the crystal shape. The two-dimensional nucleuses were observed on growth surface, which indicated there was the two-dimensional nucleation mechanism reacted on the growing process of DAST crystal. DAST crystals grown by different methods were tested by x-ray topography, and the crystal quality was analyzed. The fluorescence spectrum of DAST crystal was measured. It was showed that DAST crystal had fluorescence effect.