Figure 1: Examples of metal naphthenic acid structures. See table below for available metals.
The naphthenic acids are generally comprised of cyclopentyl and cyclohexyl carboxylic acid moieties. These acids are found globally in crude oil.1 The n number for these acids typically range from 10 – 16, but numbers upwards to 50 have been observed.2
Metal naphthenic acids are considered organic solvents and oils and do not dissolve in water ( < 50 mg/L).1 These compounds see use in: electrical equipment for insultation and cooling,3 biomarker to identify oil source maturation,4 as surfactants,5 conferring anti-corrosive properties to steel,6 a growth stimulant for bush bean plants,7 paint additives,8 and wood preservatives (for copper naphthenic acids).9
In particular, wood preservation with naphthenic acids has been well documented.9-12 Wood preservation increases the service life of already cut wood.12 It is estimated that wood-destroying fungi and insects require the United States to cut 360,000 acres of forest annually, and proper preservation techniques, including copper naphthenic acid treatment, can offset this number.12
1. Kirk-Othmer Encyclopedia of Chemical Technology. Weinheim: Wiley-VCH. 2000.
2. Energy & Fuels, 2001, 15, 1505.
3. EEE Trans. on Dielectr.and Electr. Insul., 2019, 26, 240.
4. J. Environ. Sci. Health A, 2004, 39, 1989.
5. Energy Fuels, 1999, 13, 333.
6. J. Mater. Eng. Perform., 1999, 38, 48.
7. Agron, J., 1970, 62, 644.
8. Prepr. – Am. Chem. Soc. Div. Pet. Chem., 1998, 3, 131.
9. Bioresour. Technol., 2005, 96, 1131.
10. Forest Prod. J., 2002, 52, 60.
11. Agricultural Chemicals: Book IV – Fungicides, 1991.
12. Encyclopedia of Pest Management, 2002.
93-2027: Calcium naphthenate, ~35% in mineral spirits (4% Ca) [61789-36-4]
24-2427: Chromium(III) naphthenate, 30-40% in heavy naphtha (2-2.5% Cr) [61788-69-0]
93-2424: Chromium(III) naphthenate, ~30% in mineral spirits (2% Cr) [61788-69-0]
93-2710: Cobalt naphthenate, ~53% in mineral spirits (6% Co) [61789-51-3]
29-6750: Copper(II) naphthenate, 77% in mineral spirits (8% Cu) [1338-02-9]
93-1236: Magnesium naphthenate (3.5-8.0% Mg) [68424-71-5]
93-2516: Manganese naphthenate, 56% in mineral spirits (6% Mn) [1336-93-2]
93-2829: Nickel(II) naphthenate, ~60% in toluene (6-8% Ni) [61788-71-4]
93-6206: Samarium(III) naphthenate (8-10% Sm) [61790-20-3]
23-4400: Vanadyl naphthenate, 35% in naphthenic acid (2.8-3.2% V) [68553-60-6]
93-3908: Yttrium(III) naphthenate, ~60% in toluene (7-13% Y) (99.9%-Y) (REO) [61790-20-3]
93-3037: Zinc naphthenate, 65% in mineral spirits (10% Zn) [12001-85-3]