PYROLIGNEOUS ACID

Chemical properties

Crude, yellow to red liquid. A mixture of materials from wood distillation. Crude product contains methanol, acetic acid, acetone, furfural, and various tars and related products Miscible with water and alcohol.

Chemical properties

Pyroligneous acid is a smoke-flavoring solution. It is also referred to as liquid smoke, char-smoke flavor, wood vinegar and pyroligneous acid extract. Pyroligneous acid has a distinctive odor, an acrid smoky smell. For a detailed description of this flavoring solution, refer to Burdock (1997).

The Uses of PYROLIGNEOUS ACID

Largely for smoking meats.

Definition

PYROLIGNEOUS ACID is a volatile, complex combination obtained by the destructive distillation of wood. It may contain acetic acid, acetone, furfural, methanol and various tars.

General Description

A yellow to red liquid containing methyl alcohol acetic acid, acetone and other materials. Flash point below 141°F. Less dense than water. Vapors heavier than air.

Air & Water Reactions

Highly flammable. Slightly soluble in water.

Reactivity Profile

PYROLIGNEOUS ACID is a carboxylic acid. Carboxylic acids donate hydrogen ions if a base is present to accept them. They react in this way with all bases, both organic (for example, the amines) and inorganic. Their reactions with bases, called "neutralizations", are accompanied by the evolution of substantial amounts of heat. Neutralization between an acid and a base produces water plus a salt. Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are slightly soluble in water. Soluble carboxylic acid dissociate to an extent in water to yield hydrogen ions. The pH of solutions of carboxylic acids is therefore less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve as the neutralization generates a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt. Such reactions occur in principle for solid carboxylic acids as well, but are slow if the solid acid remains dry. Even "insoluble" carboxylic acids may absorb enough water from the air and dissolve sufficiently in PYROLIGNEOUS ACID to corrode or dissolve iron, steel, and aluminum parts and containers. Carboxylic acids, like other acids, react with cyanide salts to generate gaseous hydrogen cyanide. The reaction is slower for dry, solid carboxylic acids. Insoluble carboxylic acids react with solutions of cyanides to cause the release of gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are generated by the reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides. Carboxylic acids, especially in aqueous solution, also react with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Their reaction with carbonates and bicarbonates generates a harmless gas (carbon dioxide) but still heat. Like other organic compounds, carboxylic acids can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. A wide variety of products is possible. Like other acids, carboxylic acids may initiate polymerization reactions; like other acids, they often catalyze (increase the rate of) chemical reactions.

Health Hazard

Inhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.