Cellobiose is a disaccharide with the formula [HOCH2CHO(CHOH)3]2O. Cellobiose, a reducing sugar, consists of two β-glucose molecules linked by a β(1→4) bond. It can be hydrolyzed to glucose enzymatically or with acid. Cellobiose has eight free alcohol (OH) groups, one acetal linkage and one hemiacetal linkage, which give rise to strong inter- and intra-molecular hydrogen bonds. It can be obtained by enzymatic or acidic hydrolysis of cellulose and cellulose rich materials such as cotton, jute, or paper.
Treatment of cellulose with acetic anhydride and sulfuric acid, gives cellobiose octoacetate, which cannot engage in hydrogen bonding and is soluble in nonpolar organic solvents.