Seeking help regarding vanilla aldehyde crystals
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This post was last edited by wbp on 2009-8-12 at 12:22. We are currently facing some problems during crystallization in our testing workshop: vanillin serves as the solute, while a methanol-water solution acts as the solvent. Discoloration occurs at 38°C; with a stirring speed of 50 Hz, a large amount of substance precipitates suddenly at 32°C. The reason it is referred to as a substance rather than crystals is that the precipitate is in powder form and lacks a crystalline structure. I tried it again in the laboratory using the same proportions: 100 mL of vanilla aldehyde, 100 mL of methanol, and 320 mL of pure water. The color shift temperature was 36°C, and the transition point temperature was 29.6°C. Crystals still cannot be formed; the precipitates resemble bean dregs, and their amount is extremely large, causing the stirring mechanism to stop working. Please ask an experienced sea traveler to help me analyze and solve this~
The ratio of water to methanol is incorrect; increase the proportion of methanol accordingly
Too many nuclei formed suddenly; adjust the concentration and temperature and try again
Could the brother on the 2nd floor explain it in more detail? We thought the same way, but we increased the amounts of methanol and water in proportion: 100 mL of vanilla extract, 125 mL of methanol, and 400 mL of water. As a result, the color shift temperature was reduced only, and kernel formation remained unsatisfactory. The precipitates had a shape similar to millet grains, and they turned into powder when crushed by hand. What’s most annoying is that once these precipitates accumulate in large quantities, they form clumps that cause the mixing process to stop!
Clumping is mainly a problem of particle size control. The solvent can be adjusted, and the crystallization process can be improved accordingly to increase the crystal growth time.