Naphthenic add

NAPHTHENIC ACIDS. The term naphthenic acid, as commonly used in the petroleum industry, refers collectively to all of the carboxylic adds present m crude oil. Naphthenic adds are classified as monobasic carboxylic acids of the general formula RCOOH, where R represents the naphthene moiety consisting of cyclopentine and cyclohexane derivatives. Naphthenic adds are composed predominantly of alkyl-substituted cycloaliphatic carboxylic adds, with smaller amounts of acyclic aliphatic (paraffinic or fatty) acids. Aromatic, okfinic. hydroxy, and dibasic acids are considered to be minor components. Commercial naphthenic aads also contain varying amounts of unsaponifiable hydrocarbons, phenolic compounds, sulfur compounds, and water. The complex mixture of adds is derived from straight-run distillates of petroleum, mostly from kerosene and diesel fractions. See also Petroleum. 

Cobalt, Cobalt acetate (ous) Cobalt linoleate (ous) Cobalt naphthenate (ous) Cobalt octoate. Cobalt sulfate (ous) Cobalt tallate Copper linoleate Copper naphthenate. Copper octoate. Copper tallate Erucic acid, 2-Ethylhexolc add. Iron linoleate Iron naphthenate. Iron octoate Iron tallate Lead linoleate Lead naphthenate. Lead octoate. Lead tallate. Lithium drier Magnesium stearate Manganese acetate (ous) Manganese linoleate Manganese naphthenate Manganese octoate Manganese tallate. Menhaden oit Naphthenic add. Nickel octoate Nuact NOPB Prifrac 2990 Rosin-, Sorbitan tallate Strontium drier. Zinc 2-ethylhexanoate Zinc naphthenate Zinc tallate. Zirconium octoate... 

Naphthenic acid are most significant environmental contaminants. They are comprised of a large collection of saturated aliphatic and alicyclic carboxylic acids found in hydrocarbon deposits (petroleum, oil sands bitumen, and crude oils). Moreover, they are toxic components in refinery wastewaters and in oil sands extraction waters. In addition, there are many industrial uses for naphthenic acids, so there is a potential for their release to the environment from a variety of activities. Studies have shown that naphthenic adds are susceptible to biodegradation, which decreases their concentration and reduces toxidty. 

They are described by the general chemical formula C H2n+z02, where n indicates the carbon number and Z is zero or a negative, even integer that spedfies the hydrogen defidency resulting from ring formation. Naphthenic adds have dissociation constants, which is typical of most carboxylic acids. Naphthenic acids are non-volatile, chemically stable, and act as surfactants (Seifert, 1975). 

Toxicity values of some naphthenic adds to Tetrahymena pyriformis were obtained from the literature (Schultz, 1997) and reported in Table 3. Population growth impairment was assessed after 40h with the common ciliate Tetrahymena pyriformis. The experimental data for rat (oral LD50 values) were collected from the literature (ChemIDplus). 

The results of estimation of naphthenic acids for persistence, bioaccumulation and toxicity are presented in Table 2. The components of naphthenic adds are commonly classified by their structures and the number of carbon atoms in the molecule. 

Naphthenic adds are a family of carboxylic acid surfactants, primarily consisting of cyclic terpenoids used in source and geochemical charaderisation of petroleum reserves (Brient, Wessner Doyle, 1995). The compwimd group is composed predominately of alkyl-substituted cycloaliphatic carboxyUc adds with smaller amounts of acyclic aliphatic (paraffinic or fatty) acids. Aromatic olefinic, hydroxyl and dibasic adds are also present as minor components of naphthenic adds. The cydoaliphatic adds include single rings and fused multiple rings. 

Analysis of data in Table 2 reveals that as all naphthenic adds are not persistence, bioacculumative and toxic (Fish ChV), but some compounds are exception about their chronic toxic. The compoimds with moderate toxic (0.1-10 mg/1) are decanoic and cyclohexanepentanoic acids. 

Fig. 1. Plot of toxicity to Tetrahymena pyiiformis vs log P for naphthenic adds showing baseline toxidty.

The most common accelerators for methyl ethyl ketone peroxide and cyclohexanone peroxide are salts of metals which exhibit more than one valency. The most widely used metal of this kind is cobalt, although salts of cerium, iron, manganese, tin and vanadium also find some application. In order to be effective as an accelerator a metal salt must be soluble in the polyester resin. The most commonly used salts are naphthenates, which are readily soluble octoates also may be used. (Naphthenic add is extracted from the gas oil and kerosene fractions of petroleum and consists of a complex mixture of carboxylic acids of substituted cyclopentanes and cyclohexanes. ) The decomposition of a hydroperoxide (ROOH) by a metal salt such as cobalt naphthenate to give free radicals proceeds according to the following chain reaction ... 

Drying Oil n Any of several plant-derived polyunsaturated oils, such as linseed, oiticica, and tung, that, when exposed to air, form dry, tough, durable films. Linseed oil to be used in paints and varnishes today is usually boiled with cobalt or manganese salts of linoleic or naphthenic adds to shorten its drying time. 

Iron Driers Iron salts of naphthenic add, 2-ethyl hexoic acids or other acids which actively accelerate polymerization at elevated temperatures, but are only feebly active at room temperature. The presence of the very dark ferric ion makes them applicable in dark or tinted finishes. The British call then iron soaps. (Wicks, Z. N., et al., Organic Coatings Science and Technology, 2 Ed.,... 

Synonyms Naphthenic add aluminum salt Properties Rubbery yel. substance Toxicology Mod. toxic by IP route... 

MCRS Semi-Refined Naphthenic Add Rheodol SP-S10V... 

Naphthenic acids are mixture of several cyclopentyl and cyclohexyl carboxylic acids, which are natural constituents in many petyroleum sources. The main fraction contains carboxylic acids with a carbon backbone of 9 to 20 carbons. The naphtha fraction of the crude oil is oxidized and yields naphthenic add. The composition differs with the crude oil composition and the conditions during raffination and oxidation (Walter et al., 2002). 

Typically naphthenic adds are effectively removed from crude fractions by aqueous base washing (Varadaraj Savage, 2000, Sartori et al., 2000), but serious emulsion problems are presented. 

Rudzinski, W. E. Oehlers, L. Zhang, Y. (2002). Tandem Mass Spectrometric Characterization of Commercial Naphthenic Adds and a Maya Crude Oil. Energy Fuels, 16,1178-1185, ISSN 0887-0624. 

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