Chitin can dissolve well in aqueous potassium hydroxide (KOH) through a freeze-thawing process. This dissolution in KOH without urea is enhanced with decreasing temperature and increasing dissolution time.

Hope this helps answer your question.

Professor Yehia Khalil

Yale University

USA

Dear Siriporn Taokaew,

As well described by Prof. Yehia Khalil,

A modified freezing thawing cyclic process apply to dissolve Chitin(C8H13O5N)n in NaOH solution or KOH solution. This dissolution in KOH or NaOH without urea is enhanced with decreasing temperature and increasing dissolution time. chitin can dissolve well in aqueous KOH through a freeze-thawing process, and the dissolution power of the alkali solvent systems is in the order of KOH > NaOH > LiOH aqueous solution, which is totally contrary to that of cellulose in the alkali aqueous solution (i.e., LiOH > NaOH ≫ KOH). A transparent homogeneous solution is obtained. It utilize directly for preparing the superabsorbent polymer by grafting copolymerization under static solution condition without Nitrogen Protection. Chitin, as the second most abundant polysaccharide in nature, is bio-renewable, biocompatible, environmentally friendly, biodegradable and bio-functional, having useful applications as a chelating agent, drug carrier, membrane, water treatment additive, biodegradable pressure-sensitive adhesive tape and wound-healing agent. It is also known to be one of the natural hetero-polysaccharides with low toxicity when administrated into animal bodies.

https://www.deepdyve.com/lp/elsevier/homogeneous-synthesis-of-chitin-based-acrylate-superabsorbents-in-naoh-8r6OTluRzH

https://www.researchgate.net/post/How_can_chitosan_be_dissolved_in_NaOH_01N_precisely?_tpcectx=profile_questions

http://link.springer.com/article/10.1007/s10570-016-0932-z

Thank you so much. Anyhow, using urea promotes solubilizing of chitin and reduces usage of strong base, right? 

That is correct.

Professor Yehia Khalil

Yale University

USA

thank you so much Prof.