Purified chitin was chlorinated with an equimolar mixture of N-chlorosuccinimide and triphenylphosphine under homogeneous conditions in a 5% (w/v) solution of LiCl in N,N-dimethylacetamide at 70-85"C. 13C NMR spectroscopy of the chlorinated products and gas chromatographic-mass spectrometric analysi
Reaction of dichloroallose units in a chlorodeoxycellulose with lithium chloride under homogeneous conditions in N,N-dimethylacetamide
β Scribed by Ken-ichi Furuhata; Nobuyoshi Aoki; Shigeru Suzuki; Norihiro Arai; Munenori Sakamoto; Yasuo Saegusa; Shigeo Nakamura
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 617 KB
- Volume
- 258
- Category
- Article
- ISSN
- 0008-6215
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β¦ Synopsis
The reaction of methyl 3,6-dichloro-3,6-dideoxy+D-allopyranoside with lithium chloride in NJ-dimethylacetamide (DMA) was studied in relation to the possible conversion of 3,6-dichloro-3,6-dideoxy-D-allose units in a chlorodeoxycellulose during synthesis in a LiCI-DMA solvent system. Methyl 3,6-dichloro-3,6-dideoxy-/3-D-glucoside was formed; the reaction was reversible and the equilibrium was on the glucoside side. GLC analysis of the hydrolyzates of chlorodwcellulose samples after treatment with LiCl showed that the dichloroallose units were partly converted into 3,6-dichloro-3,6-dideoxy-D-glucose units. A kinetic study showed that the rate of conversion of the dichloroallose unit into the dichloroglucose unit was lower than that of the dichloroalloside into the dichloroglucoside, and the amounts of the two units at equilibrium were calculated to be close to each other. Based on the values of the kinetic parameters obtained, the conversion of the dichloroallose units into the dichloroglucose units during the chlorination of cellulose in LiCl-DMA was estimated to be negligibly small under typical reaction conditions.
π SIMILAR VOLUMES
The homogeneous preparation of a cellulose p-toluenesulfonate (tosylate) in N,N-dimethylaceta-mid+lithium chloride (DMAc-LiCl) is hampered by solvolysis of the p-toluenesulfonyl chloride (tosyl chloride). This Vilsmeier-Haack type reaction results in competitive formation of cellulosep-toluenesulfon
Chitin regenerated from LiCI-N,N-dimethylacetamide (DMA) was found to dissolve in 10 g/dL LiBr-DMA. The bromination of the regenerated chitin proceeded to a large extent (DS by bromine up to 0.94) with equimolar amounts of N-bromosuccinimide and triphenylphosphine under homogeneous conditions in LiB
Rate constants and activation parameters for decrystallization of Avicel PH-101 cellulose, and bagasse-based cellulose in presence of LiCl/N,N-dimethylacetamide solvent system have been determined from dependence of the index of crystallinity of cellulose, Ic, on time, under nonisothermal conditions