Determination of substituent distribution in cellulose ethers by 13C- and 1H-n.m.r. studies of their acetylated derivatives: O-(2-hydroxypropyl)cellulose

✍ Scribed by Yasuyuki Tezuka; Kiyokazu Imai; Mitsuyoshi Oshima; Tohru Chiba

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 586 KB
• Volume: 196
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(90)84101-y

✦ Synopsis

Structural characteristics of 0-(2-hydroxypropyl)cellulose

samples, namely the molar substitution (mol. subst.), the total degree of substitution (d.s.), and the individual degree of substitution of hydroxyl groups on the glucose residues for a wide mol. subst . range of samples were determined after peracetylation by rH-and 13C-n.m.r. analyses. The mol. subst. value was determined by comparing the acetyl methyl proton signal with that of the 2-hydroxypropyl methyl group. The acetyl carbonyl carbon signal of acetylated 0-(2-hydroxypropyl)ceellulose samples was found to split into a quadruplet in Me,SO at loo", reflecting the position of the substituent (2, 3, and 6) on the glucose residue and of the (oligo-)propylene oxide substituent end-group, and allowing determination of the substituent distribution as well as the total degree of substitution in a series of O-(Zhydroxypropyl)cellulose samples.