Formation and stability of cellulose–copper–NaOH crystalline complex

• Published in: Cellulose (London) Vol. 21; no. 2; pp. 999 - 1006
• Main Authors: Ogawa, Yu, Hidaka, Hitomi, Kimura, Satoshi, Kim, Ung-Jin, Kuga, Shigenori, Wada, Masahisa
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.04.2014; Springer Netherlands; Springer Nature B.V
• Subjects: Ammonia; Bioorganic Chemistry; Cellulose; Cellulose fibers; Ceramics; Chemistry; Chemistry and Materials Science; Composites; Coordination compounds; Copper; Crystal structure; Glass; ions; Natural Materials; Organic Chemistry; Original Paper; Physical Chemistry; Polymer Sciences; Sodium hydroxide; Sustainable Development; Synchrotron radiation; X-ray diffraction; X-ray diffraction; Alkali-cellulose II; Na-cellulose II(Cu); Na-cellulose IIA
• ISSN: 0969-0239; 1572-882X
• DOI: 10.1007/s10570-013-9977-4

We investigated the crystal structure of alkali-celluloses, Na-cellulose IIA and II(Cu), formerly known as Na-cellulose IIB, by synchrotron X-ray diffraction. Na-cellulose IIA, formed from cellulose I by high-concentration NaOH treatment, has a fiber repeat of 15 and a threefold-like helical conformation. Na-cellulose II(Cu), prepared by treating cellulose I with copper-saturated alkali solution, also has a fiber repeat of 15 with threefold helical symmetry. Incorporation of Cu(II) ions into cellulose was confirmed by multiwavelength anomalous diffraction. Monitoring by X-ray diffraction revealed that the formation of this complex from cellulose I is remarkably slow, probably because of the involvement of copper ion. The stability of alkali-cellulose II(Cu) was tested to estimate the influence of the presence of copper in the crystal. Na-cellulose II(Cu) characteristically dissolved in aqueous ammonia solution, indicating strong coordination of copper ion to cellulose.