What Is Pyroligneous Acid?
Pyroligneous acid, commonly known as wood vinegar or wood acid, is a highly acidic (pH 1.5 to 3.7) liquid obtained from the dry distillation of wood. It contains about 90% water and about 5% acetic acid, along with roughly 200 other organic components such as alcohols, esters, and phenols. The composition of pyroligneous acid varies depending on the type of wood used.
When wood is subjected to dry distillation, the resultant liquid typically separates into two or three layers.
Uses of Pyroligneous Acid
Pyroligneous acid has a wide range of applications, particularly in agriculture, livestock production, and as a feed additive. Its uses have been developed to leverage its various effects based on the dilution ratio.
1. Disinfection and Sterilization
A 1 to 100 times diluted solution of pyroligneous acid exhibits sterilizing effects, primarily due to the acetic acid and alcohol content. It can be used for soil disinfection by applying a highly concentrated solution (diluted 20-30 times) to the soil before planting crops. The bactericidal effect diminishes after 10 to 14 days, making it safe for subsequent crop growth. Additionally, pyroligneous acid has been used in treating athlete’s foot and in traditional medicine.
2. Inhibition of Plant Growth
A solution diluted 200 to 300 times with wood acid effectively inhibits weed growth. Pyroligneous acid’s aroma is repellent to many creatures, making it useful for repelling harmful insects and pests in agriculture and gardening.
3. Promotion of Crop Growth
Diluting pyroligneous acid 500 to 1000 times can promote the growth of plant shoots and roots. Applying low concentrations to crops and turf every 10 to 15 days can enhance root and shoot growth. The organic acid components, such as acetic acid and propionic acid, help to convert soil minerals into a form more easily absorbed by plants.
4. Other Uses
Pyroligneous acid is also used in the production of preservatives, deodorants, and acetic acid lime.
Other Information on Pyroligneous Acid
1. Production of Pyroligneous Acid
Pyroligneous acid is produced by carbonizing wood at high temperatures, then cooling and condensing the smoke. The steam and smoke generated when wood is heated at high temperatures are collected and condensed to form wood vinegar, which contains various organic and inorganic compounds. Wood is heated in a sealed container to promote carbonization, producing charcoal and smoke. The liquid obtained is distilled to isolate and purify pyroligneous acid, while the charcoal can be used as fuel or fertilizer.
2. Safety Information
While pyroligneous acid has a strong pungent odor, it is not toxic and generally does not cause skin irritation. However, it is recommended to use gloves, masks, and protective eyewear when handling the substance.