Optimization of the synthesis modes of water-soluble sulfonic derivatives of lignin from wood waste

Abstract

Relevance. When processing wood, up to 40% of waste is generated, which includes shavings, sawdust, wood dust, bark parts and substandard wood of various shapes and sizes. Secondary wood waste contains lignin, which is a source for the production of salts of lignosulfonic acids – lignosulfonates. The possibility of using these compounds as pigment dispersants is due to the amphiphilic structure of their molecules. The targeted synthesis of lignosulfonates from secondary wood waste, on the one hand, solves the problems of ensuring waste-free production, and on the other hand, obtaining a marketable product with dispersing properties. Aim. Optimization of the method for obtaining a water-soluble dispersant from wood waste. Methods. Probabilistic deterministic method of experiment planning, spectrophotometry method, computer microscopy method. Results and conclusions. The paper shows the possibility of targeted synthesis of lignosulfonate LSs from birch sawing waste. Optimization of synthesis modes was carried out using probabilistic-deterministic planning methods and a generalized model was obtained that allows estimating the yield of lignosulfonate. The authors studied the effect of three modifiers on the dispersion of titanium dioxide in aqueous acrylic enamel. It is shown that the introduction of LSs, LSt and Dispers 715w at the level of 1.0–0.5 g/dm3 leads to a finer dispersion of the pigment. The best dispersion indicators are observed at a LSs content of 0.5 g/dm3, while the average diameter decreases by 3.1 times (from 8.4 to 2.6 microns). With the content of synthesized LSs at the level of 1.0 g /dm3 in a water-acrylic paint coating, the degree of protection of steel in sulfuric acid solutions was at least 62%.

Keywords

• secondary wood waste
• lignin sulfates
• lignosulfonate
• experiment planning
• acrylic dispersion
• synthesis