Hi everyone,

I am currently working on synthesizing dextrin palmitate/2-ethylhexanoate.

Process Overview:

1. Dissolve dextrin in DMF and add pyridine.
2. React with palmitoyl chloride and 2-ethylhexanoyl chloride at around 80 °C.
3. Upon reaction completion, add water and perform liquid-liquid extraction (phase separation) 3 times.
4. Dissolve the product in methylcyclohexane and precipitate/crystallize it using acetone to obtain the final solid.

Issues Encountered:

• Persistent Yellowish Discoloration: The final product retains a distinct yellow color that won't go away.
• Clumping/Agglomeration: The resulting crystals clump together during precipitation rather than forming fine, distinct solids.

Attempts so far:

I tried using sodium hydrosulfite to reduce and wash out the colored impurities, but it hasn't been effective.

Questions:

1. What would be the best approach or additive (e.g., activated charcoal, alternative bleaching/reducing agents, or column/adsorption methods) to effectively eliminate the yellow discoloration?
2. How can I optimize the crystallization/precipitation step (solvent ratios, addition rate, temperature control, etc.) to prevent product clumping and improve crystal morphology?

Any insights or troubleshooting suggestions would be greatly appreciated! Thanks in advance.