| 摘要 |
A sulphonated lignin prod. having an organically bound sulphonic acid content of at least 4.1 moles/mole lignin, is prepd. by dissolving a dry lignin cod., produced as a by-prod. of kraft or sulphite wood-pulping processes, with sulphuric acid of concn. at least 95%, pref. about 98%, while keeping the temp. of the reaction below 40 deg.C, to sulphonate the lignin. |
