METHOD OF PRODUCING SOAP FROM BLACK LIQUORS OF SULPHATE PRODUCTION Russian patent published in 2021 - IPC C11B13/00 

FIELD: chemistry.

SUBSTANCE: invention relates to methods of producing secondary products from spent liquors after cooking predominantly hardwood. Method of producing soap from black liquors of sulphate production of wood species, including addition of surfactants to black liquor. In black liquor with density of 1.02–1.12 g/cm³ and temperature of 20–25 °C is sequentially introduced aqueous solutions of cationic surfactant (CS) of octadecyldimethylbenzylammonium chloride of formula {C₁₈H₃₇(CH₃)₂(CH₂C₆H₅)N}Cl and a nonionic surfactant (NS) of oxyethylated monoalkylphenol based on propylene trimers of formula C₉H₁₉C₆H₄O(C₂H₄O)₆H at a ratio of black liquor:CS:NS 1:0.0001:0.0009–1:0.0002:0.0008, wherein sulphate soap is separated by settling black liquor for 4–10 hours and at temperature of 20–25 °C.

EFFECT: invention enables to obtain sulphate soaps at low temperatures from unpaired black liquors after cooking predominantly hardwood with high content of unsaponifiable substances in the obtained sulphate soap with biologically active substances based on β-sitosterol with simultaneous simplification of black liquor processing technology and reduction of energy consumption.

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