| 摘要 |
A sulphonated lignin prod. has an organically bound sulphonic acid content of at least 4.2 moles per 1000g lignin and has complete water solubility at all levels of pH. It is prepd. by dissolving a dry lignin cpd. (I) in oleum, whilst maintaining the reaction temp. below 40 deg.C, to sulphonate the lignin. (I) is recovered as a by-prod. of kraft or sulphite wood pulping processes. (I) is a sulphomethylated lignin and the organically bound sulphonic acid content is up to 4.7. |
