Naphthenic acid

Naphthenic ( CAS number: 1338-24-5 ) is a technical mixture of alkylated cyclopentane and cyclohexanoic, obtained by alkaline extraction of petroleum fractions, preferably gas oil and spindle oil, and acidification of the resulting solution. The name is derived from naphtha (Greek for oil ).

Properties

The composition of naphthenic acids varies widely depending on the starting material and can be empirically described as having the empirical formula CnH2n- 2O2 where n is in the range between about 10 and 22. Due to their corrosive properties to the feed and production they are in crude oil, containing up to 4% naphthenic undesirable.

The order in which the compound occurs in crude oil, can be (total acid number) described by the TAN. The melting point of the naphthenic acids is in the range of -35 to 2 ° C, the boiling point in the range of 140 to 370 ° C, the density is about 0.98 g · cm -3. The separation of the naphthenic acids is carried out by neutralization with about 10% sodium hydroxide solution. The salts of naphthenic acids are water soluble and dissolve in the water fraction of the crude oil. By acidifying the aqueous phase, the naphthenic acids can be recovered.

Use

The salts of naphthenic acids are called naphthenates (eg zinc naphthenate, copper naphthenate, Kalziumnaphthenat, Aluminiumnaphthenat, ...). They have a technical meaning, for example, as desiccants (eg cobalt naphthenate as a curing accelerator in the oil paint industry ) for varnishes and as fungicides in the wood industry (eg copper naphthenate ). The thickener of napalm M is an aluminum soap of naphthenic acid and palmitic acid. The sodium salts are used as emulsifiers for pesticides.