Naphthenic acids
Naphthenic acids are a technical mixture of alkylated cyclopentane and cyclohexanoic acids , obtained by alkaline extraction of petroleum fractions , preferably gas oil and spindle oil, and acidification of the solution obtained. The name is derived from naphtha (Greek for petroleum).
properties
| safety instructions | |||||||
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| Surname |
Naphthenic acids |
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| CAS number |
1338-24-5 |
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| EC number |
215-662-8 |
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| ECHA InfoCard | |||||||
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The composition of naphthenic acids varies greatly depending on the starting product and can be empirically described using the empirical formula C n H 2n − 2 O 2 , where n is in the range between approximately 10 and 22. Due to their corrosive properties on the conveyor and production systems, they are undesirable in crude oil, which contains up to 4% naphthenic acids.
The order of magnitude in which the compound occurs in crude oil can be described by the TAN (total acid number). The melting point of naphthenic acids is in the range from −35 to + 2 ° C, the boiling point in the range from 140 to 370 ° C, and the density is around 0.98 g · cm −3 . The naphthenic acids are separated off by neutralization with approximately 10% sodium hydroxide solution . The salts of naphthenic acids are water-soluble and dissolve in the water fraction of the crude oil. The naphthenic acids can be recovered by acidifying the aqueous phase.
use
The salts of naphthenic acids are called naphthenates . Metal naphthenates such as B. naphthenate , copper naphthenate , calcium naphthenate and Aluminiumnaphthenat have an industrial importance as drying agents (eg. As cobalt as a curing accelerator in the oil paint industry) for varnishes and as fungicides in the timber industry (eg. As copper naphthenate). The thickener of Napalm is an aluminum soap of naphthenic acid and palmitic acid . The sodium salts are used as emulsifiers for pesticides used.
Analytics
The coupling of HPLC with mass spectrometry can be used for the qualitative and quantitative determination of naphthenic acids . The coupling of gas chromatography with mass spectrometry with appropriate sample preparation can also be used for the analysis of naphthenic acids in fish and their various tissue samples.
Web links
- Mark P. Barrow: composition of naphthenic acids (English)
- Pratap Rikka: Spectometric Identification of Naphthenic Acids Isolated from Crude Oil (PDF, 520 kB)
- Patent-de: Removal of naphthenic acids from crude oils, crude oil mixtures and crude oil distillates
Individual evidence
- ↑ a b Data sheet naphthenic acids from Sigma-Aldrich , accessed on March 5, 2018 ( PDF ).
- ↑ Patent-DE: Use of sulphodizing agents in high-temperature corrosion control (PDF file; 559 kB).
- ↑ International Chemical Safety Card (ICSC) for Naphthenic Acids at the National Institute for Occupational Safety and Health (NIOSH), accessed December 26, 2017.
- ↑ External identifiers or database links for zinc naphthenate : CAS number: 12001-85-3, EC number: 234-409-2, ECHA InfoCard: 100.031.268 , GESTIS substance database : 124616 , PubChem : 22833313 , ChemSpider : 17215406 , Wikidata : Q72516902 .
- ↑ External identifiers of or database links to copper (II) bis (2-naphthenate) : CAS number: 1338-02-9, EC number: 215-657-0, ECHA InfoCard: 100.014.234 , GESTIS substance database : 570170 , PubChem : 15607801 , ChemSpider : 13645570 , Wikidata : Q26841335 .
- ↑ External identifiers or database links for calcium naphthenate: CAS number: 61789-36-4, EC number: 263-055-1, ECHA InfoCard: 100.057.305 , GESTIS substance database : 530204 , PubChem : 20138397 , ChemSpider : 14761605 , Wikidata : Q72514970 .
- ↑ stanfordmaterials.com: Naphthenates.
- ↑ Wissen.de: naphthenic acids ( Memento from May 19, 2010 in the Internet Archive ).
- ↑ P. Brunswick, D. Shang, G. van Aggelen, R. Hindle, LM Hewitt, RA Frank, M. Haberl, M. Kim: Trace analysis of total naphthenic acids in aqueous environmental matrices by liquid chromatography / mass spectrometry-quadrupole time of flight mass spectrometry direct injection. In: J Chromatogr A. 1405, Jul 31, 2015, pp. 49-71. PMID 26074097 .
- ↑ R. Hindle, M. Noestheden, K. Peru, J. Headley: Quantitative analysis of NAPHTHENIC acids in water by liquid chromatography-mass accurate time-of-flight mass spectrometry. In: J Chromatogr A. 1286, Apr 19, 2013, pp. 166-174. PMID 23518264 .
- ↑ RF Young, LM Michel, PM Fedorak: Distribution of naphthenic acids in tissues of laboratory-exposed fish and in wild fishes from near the Athabasca oil sands in Alberta, Canada. In: Ecotoxicol Environ Saf. 74 (4), May 2011, pp. 889-896. PMID 21216009 .