| 摘要 |
A m-cresolsulphonic acid-formaldehyde condensation product is obtained by purifying an aqueous solution of m-cresolsulphonic acid containing sulphuric acid as impurity by adding a slight excess (with regard to the sulphuric acid) of barium carbonate or hydroxide, filtering off the precipitated barium sulphate, removing barium ions from the resulting solution by means of a cationic exchange resin and condensing the purified m-cresolsulphonic acid with formaldehyde, the molar ratio of m-cresolsulphonic acid to formaldehyde being from 3:1.125 to 3:1.85.ALSO:A m-cresolsulphonic acid-formaldehyde condensation product is obtained by purifying an aqueous solution of a m-cresolsulphonic acid (obtained in the form of a sulphonation product of m-cresol treated with sulphuric acid) by treating said solution with a slight excess (with regard to sulphuric acid) of barium carbonate or barium hydroxide, filtering off the barium sulphate, removing barium ions from the resulting solution by means of a cationic exchange resin, and then condensing the purified solution with formaldehyde, the molar ratio of m-cresolsulphonic acid to formaldehyde being from 3:1.125 to 3:1.85.ALSO:A therapeutic composition having astringent properties comprises a condensation product of m-cresolsulphonic acid with formaldehyde, the molar ratio of the acid to formaldehyde being from 3:1.125 to 3:1.85 and a suitable diluent, for example an aqueous solution thereof. |
