Laser photolysis of carboxymethylated chitin derivatives in aqueous solution. Part 2. Reaction of OH* and SO4*- radicals with carboxymethylated chitin derivatives.
The reactions of OH* or SO4*- radicals with carboxymethyl chitin (CM-chitin) and its deacetylated product, carboxymethyl chitosan (CM-chitosan), were investigated in aqueous solutions using a laser photolysis technique. The rate constants of the reactions of OH* and SO4*- radicals with CM-chitosan are always higher than those for CM-chitin, indicating that the amino-group could increase the reactivity of carboxymethylated chitin derivatives. The rate of the reactions of CM-chitin and CM-chitosan with OH* radical was found to decrease at lower pH when polymers chains tend to the coiled conformation. In comparison, the rate constant of the reaction of SO4*- radicals with CM-chitin or CM-chitosan decreased with pH, indicating that CM-chitin or CM-chitosan has a higher reactivity with the SO4*- radical at low pH due to the protonation of the amino group.
Nuclear Engineering Research Laboratory, School of Engineering, University of Tokyo, Shirakata-Shirane 2-22, Tokai-mura, Naka-gun, Ibaraki-ken, 319-1188 Japan. mlzhai@chem.pku.edu.cn
Maolin
M
Zhai
Hisaaki
H
Kudoh
Radoslaw A
RA
Wach
Guozhong
G
Wu
Mingzhang
M
Lin
Yusa
Y
Muroya
Yosuke
Y
Katsumura
Long
L
Zhao
Naotsugu
N
Nagasawa
Fumio
F
Yoshii
D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D005609:Free Radicals / Q000378:metabolism* / Q000528:radiation effects; D007834:Lasers; D010782:Photolysis; D012996:Solutions; D014867:Water / Q000032:analysis / Q000737:chemistry
D005609:Free Radicals; D012996:Solutions; D014867:Water; D002686:Chitin; C044872:O-(carboxymethyl)chitin