On the Ethanolysis in Presence of NH₂OH of Presulphonated Spruce Wood Meal, and Lignoximesulphonic Acid

Studies on the Sulphite Cooking. Part 5

Abstract

Each 20g of presulphonated spruce wood meal (solid lignosulphonic acid; Klason lignin and sulphur content are 25.2% and 0.9%, respectively) was treated with 200 cc of 3% ethanolic HCl and 4.2g NH₃OH•HCl in boiling water bath during 1.5_??_28 hrs. After 10_??_28 hrs., about 60% of lignin was dissolved. When ethanolic filtrates were introduced in 5l H₂O, light yellow flocculent precipitates (α) were formed. By the continuous extractions of aqueous filtrates with ether and evaporation of ether, brown syrups (β) were obtained. Average -OCH₃, nitrogen and sulphur contents of α (β) are 15.86, 1.82 and 1.66%respect-ively (13.85, 7.25 and 0.92%). Therefore, their mole ratio in a (β) is 5.1:1.3:0.5 (4.5:5.2:0.3).
From the results of the colorimetric determination of free NH₂OH and oxime by Navak-Wilson's method [J. Bacteriology, 55, 517 (1948)], and of the potentiometric titrations of α, it is confirmed that nitrogen of α is oxime-form, and α is amphorite [HO₃S-L(OCH₃)₇•(OC₂H₅)•(=NOH)₂, isoelectric point: pH 4.5], having acidic (-SO₃H) and basic groups (=NOH). Therefore, α (β) was designated, by the author, as α (β)-lignoximesulphonic acid. From results above mentioned, it is assumed that lignin molecule in presulphonated wood meal (solid lignosulphonic acid) has. carbonyl group and may be connecting with each other or with carbohydrate by means of acetal-linkage.
It is supposed that β is similar in reference to these charaters.