Acetylation and characterization of spruce (Picea abies) galactoglucomannans.
Acetylated galactoglucomannans (GGMs) are the main hemicellulose type in most softwood species and can be utilized as, for example, bioactive polymers, hydrocolloids, papermaking chemicals, or coating polymers. Acetylation of spruce GGM using acetic anhydride with pyridine as catalyst under different conditions was conducted to obtain different degrees of acetylation on a laboratory scale, whereas, as a classic method, it can be potentially transferred to the industrial scale. The effects of the amount of catalyst and acetic anhydride, reaction time, temperature and pretreatment by acetic acid were investigated. A fully acetylated product was obtained by refluxing GGM for two hours. The structures of the acetylated GGMs were determined by SEC-MALLS/RI, (1)H and (13)C NMR and FTIR spectroscopy. NMR studies also indicated migration of acetyl groups from O-2 or O-3 to O-6 after a heating treatment in a water bath. The thermal stability of the products was investigated by DSC-TGA.
Process Chemistry Centre, Laboratory of Wood and Paper Chemistry, Abo Akademi University, Turku/Abo Fi, Finland. cxu@abo.fi
Chunlin
C
Xu
Ann-Sofie
AS
Leppänen
Patrik
P
Eklund
Peter
P
Holmlund
Rainer
R
Sjöholm
Kenneth
K
Sundberg
Stefan
S
Willför
D000107:Acetylation; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000737:chemistry*; D028222:Picea / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D008351:Mannans; C443804:galactoglucomannan