Isolation of vanillin from alkaline oxidized spent sulfite liquor

Abstract

A method Is presented for isolating low-molar-mass aromatic compounds such as vanillin, acetovanillone, guaiacol, and p -hydroxybenzaldehyde, which are formed from lignin by alkaline air oxidation of spent sulfite liquor. The compounds are adsorbed on a strong cation-exchange resin in sodium form and then separated from other compounds of the oxidized spent sulfite liquor by elution with either water or a sodium carbonate solution.

Recovery of vanillin from Kraft lignin oxidation by ion-exchange with neutralization

“…The set of six variables (q Na + , q H + ,C Na + , C H + ,C V − and C VH ) can be obtained by solving Eqs. (3), (8), (12), (16), (18) and (19).…”

“…Subscripts H + hydrogen ion i species Na + sodium ion OH − hydroxyl ion V − vanillate ion VH vanillin VNa sodium vanillate of organic and inorganic acids [16]. Borregaard is one of the world's largest producers of vanillin, supplying vanillin from two different processes: one based on guaiacol route and another is based on oxidation of lignosulfonates (sulfite spent liquor) [15].…”

Separation of Vanillin and Syringaldehyde from Oxygen Delignification Spent Liquor by Macroporous Resin Adsorption

“…Ibrahim et al [7] developed a technique using molecular imprinting polymers to isolate vanillin from lignin extracted from Kraft spent liquor. Forss and coworkers [8] reported on a method of vanillin isolation from the oxidized spent sulfite liquor which used a cation-exchange resin. Zabkova et al [9] separated vanillin by adsorption ion-exchange resin using both static and dynamic approaches.…”

An integrated process to produce vanillin and lignin-based polyurethanes from Kraft lignin

“…An alternative method to recover vanillin without needing acidification of the oxidized liquor consists on using cationic ion-exchange resin as suggested by Forss et al (1986) and Fargues et al (1996a). It was found out that eluting the strongly alkaline effluent with water through a cationic ion-exchange resin in the sodium form provides good separation of vanillin, and other oxidation products, from lignin, which elutes first.…”

“…According to Forss et al (1986), in vanillin production, the treatment involving ion exchange in sodium form should be carried out between the oxidation and extraction steps. This method has some advantages such as separation of 80% of dry matter, lignin and sodium from the vanillin reactor effluent and the quantity of acid needed to neutralize the vanillin fraction is small.…”