despite the high temperature. Thus, according to diffractometer measurements the residue still has the crystallinity of the startingcellulose even after 50 % degradation. Nor do scanning electron photomicrographs show any serious changes in the structure at this stage of the degradation.
Chitin (Fluka, techn., ash content 5 %; 15.0 g) was degraded in the same way as cellulose in the temperature range 250-340ยฐC at 250bar by acetone at a flow rate of 5.Oml/min over 7.5 h. The residue amounted to 2.3 g (15.3 %). Concentration of the acetone solution by evaporation afforded 16.4g of a mobile bIack oil, which was shown by combined G ~/ M S to contain acetamide and diacetamide. Additional thin-layer chromatography showed the presence of 1,6-anhydr0-3,4dideoxy-~-~-glycero-hex-3-eno-pyranos-2-ulose. Partition of the syrup between water and chloroform afforded 4.1 g of water-soluble product and 12.3 g of chloroform extract. The main sugar component 2-acetamido-l,6-anhydro-2-deoxy-~-~-glucopyranose[~] could be recovered from the water-soluble product in 5.6 % overall yield (0.8 g) by chromatographic separation on a silica gel colutnn using acetone as eluent. he actual amount of this sugar in the pyrolysate is higher; but, further recovery by crystallization is rendered difficult by the degree of contamination with acetamide. However, in view of the ready accessibility of the starting material and the relative ease with which the reaction and isolation can be carried out, the yield is nevertheless preparatively acceptable.