FOOTNOTES:
[4] The original paper is reproduced with slight alterations.
[5] This purple colour would appear to be due to a highly dissociable compound of ω-brommethylfurfural with hydrogen bromide. The aldehyde gives yellow or colourless solutions in various solvents, which are turned purple by a sufficient excess of hydrogen bromide. Dilution, or addition of water, at once discharges the colour.
[6] Other forms of cellulose were also examined—for example, pinewood cellulose—and the substances separated from solution as thiocarbonate (powder and film). All of these gave good yields of ω-brommethylfurfural.
[7] The change is empirically represented as
C6H12O6 + HBr - 4H2O = C6H5O2Br.