Alkaline copper quaternary

Alkaline copper quaternary, usually abbreviated ACQ, is a type of water-based wood preservative product containing a soluble copper(II) complex and quaternary ammonium alkyl- or aryl-substituted compounds ("quats"). Thus the product was originally called ammoniacal copper/quaternary ammonium.

Contents

Composition

Copper complex

The copper in the preparation is in the form of a soluble complex with ammonia NH
3 or an amine such as ethanolamine N(C
2H
5)H
2). In any case, the copper content is usually expressed as a weight percentage of the amount of copper oxide CuO that would account for the copper present.

As a copper carrier, ammonia has the advantage that it will penetrate difficult-to-treat Western species better than other waterborne preservatives. Otherwise ethanolamine is preferred as copper carrier.

Quaternary ammonium cations

Quaternary ammonium cations

DDA

The quaternary ammonium cation in some formulations is didecyldimethylammonium (DDA) N+(CH
3)
2(C
10H
21)
2.

DDA is commercially produced as the carbonate, under the trade name "Carboquat". The carbonate is used instead of the chloride to reduce corrosion of the treatment equipment.

DDA carbonate is non-volatile and highly soluble in water, with near zero octanol-water partition coefficient.

ADBA

Another quaternary ammonium cation used in some formulations is alkyldimethylbenzylammonium (ADBA). The formula is N+(CH
2)
2(C
6H
5)(C
nH
2n+1), where n varies between 8 and 18.

Counterions

Both the copper complex and the quats are positive cations. The ...read more

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