MEDIUM-CHAIN PARAFFINS

Chloroparaffines are stable, persistent compounds that bioaccumulate in the environment with BCF about 1,000. Short- and medium-chain paraffines are very toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment [134]. 

There is considerable economic incentive for such a separation since the medium-chain paraffins are required for the manufacture of synthetic detergents while their removal reduces the freezing point of the raffinate stream, enhancing its value as jet fuel for high-flying aircraft. The difference in relative volatility between linear, branched, and cyclic isomers is small so that such a separation cannot be achieved simply by distillation. 

A further five chemicals (bisphenol A, deca-bromodiphenyl ether, medium-chained chlorinated paraffins, phthalates, trichloroethylene) were included due to information provided by regulators during interviews or available in referenced literature... 

F.M. Christensen S.I. and Olson, Risk assessment of Short and Medium Chain Chlorinated Paraffin s (SCCP and MCCP), Technical Report, Technical University of Denmark, 2002. 

MCCP Medium chained chlorinated paraffin(s) (C14-C16-alkyl derivatives)... 

As their name implies, chlorinated paraffins are chlorinated derivatives of paraffinic hydrocarbons. They are referred to in this review as polychlorinated alkanes (PCAs) because they are produced by chlorination of n-alkane feedstocks. Commercial PCA mixtures fall into different categories C10-C13 (short), C 4-C17 (medium) and C2o-C30 (long). These mixtures are further subcategorized into their weight content of chlorine 40-50%, 50-60%, and 60-70% [1,2]. Knowledge of the environmental chemistry of PCAs is needed because the physical properties of short and medium chain mixtures are similar to those of the... 

Ballschmiter K (1994) Determination of short and medium chain length chlorinated paraffins in samples of water and sediment from surface water. Abt Anal Chem und Umweltchem. 10 May 1994. Unpublished data report... 

Adams U, Neuwald E Comparative studies of the release of salicylic acid from medium-chain triglyceride gel and paraffin ointment bases in vitro and in vivo. Pharm Ind 1982 44 625— 629. 

Traditionally, emulsions have been used to deliver oils (castor oil, liquid paraffin) in a palatable form. This is now a minor use, but there is a growing interest in the possibility of improving delivery by the use of lipid o/w emulsions as vehicles for lipophilic dmgs (e.g. diazepam, propofol) for intravenous use. Griseofulvin, presented as an emulsion, exhibits enhanced oral absorption an emulsion of indoxole has superior bioavailability over other oral forms. Medium-chain triglycerides and mono- and diglycerides promote the absorption of ceftriaxone and cefoxitin as well as ciclosporin. 

In a recent patent Kramer and Leder (1975) describe an SCF reaction scheme for isomerizing short-chain paraffinic hydrocarbons (4-12 carbon atoms). The reaction medium consists of CO2, HBr, or HCl (as a promoter), a paraffinic hydrocarbon, and a Lewis acid catalyst (e.g., AlBr3, AICI3, BF3). 

Reth M, Ciric A, Christensen GN, Heimstad ES, Oehme M (2006) Short- and medium-chain chlorinated paraffins in biota from the European Arctic- differences in homologue group patterns. Sci Total Environ 367 252-260... 

Muir D, Braekevelt E, Tomy G, Whittle M (2002) Analysis of medium chain chlorinated paraffins in Great Lakes food webs and in a dated sediment core from Lake St. Francis in the St. Lawrence River system. Preliminary report to Existing Substances Branch, Environment Canada, Hull, Quebec. 9 pp... 

Keywords Chlorinated paraffins, Short chain chlorinated paraffins (SCCPs), Medium chain chlorinated paraffins (MCCPs), Analytical methods, Mass spectrometry... 

Houde M, Muir DCG, Tomy GT, Whittle DM, Teixeira C, Moore S (2008) Bioaccumulation and trophic magnification of short- and medium-chain chlorinated paraffins in food webs from Lake Ontario and Lake Michigan. Environ Sci Technol 42 3893-3899... 

Pribylova P, Klanova J, Holoubek I (2006) Screening of short- and medium-chain chlorinated paraffins in selected riverine sediments and sludge from the Czech Republic. Environ Pollut 144 248-254... 

Dick TA, Gallagher CP, Tomy GT (2009) Short- and medium-chain chlorinated paraffins in fish, water and soils from the Iqaluit, Nunavut (Canada), area. Int J Environ Waste Manage... 

Thomas GO, Earrar DG, Braekevelt E, Stem GA, Kalantzi OI, Martin EL, Jones KC (2006) Short and medium chain length chlorinated paraffins in UK human milk-fat. Environ Int... 

Reth M, Zencak Z, Oehme M (2005) First study of congener group patterns and concentrations of short- and medium-chain chlorinated paraffins in fish from the North and Baltic Sea. Chemosphere 58 847-854... 

Reth M, Oehme M (2004) Limitations of low resolution mass spectrometry in the electron captme negative iomzation mode for the analysis of short- and medium-chain chlorinated paraffins. Anal Bioanal Chem 378 1741-1747... 

Long range transport atmospheric transport Medium chain chlorinated paraffins Tandem-mass spectrometry... 

Poon R, Lecavalier P, Chan P, Viau C, Hakansson H, Chu I, Valli VE (1995) Subchronic toxicity of a medium-chained chlorinated paraffin in the rat. J Appl Toxicol 15 455 63... 

Interannual changes in production of total chlorinated paraffins (CPs) reported by the Flame Retardant Chemicals Association of Japan (FRCJ) [2] are shown in Fig. 2. FRCJ also reported the production and shipment of SCCPs, medium-chain chlorinated paraffins (MCCPs), and long-chain chlorinated paraffins (LCCPs) in 2001 [2] as shown in Table 1. It indicates that 500 tons per year of SCCPs were shipped, suggesting that SCCPs were not used for polyrvinyl chloride. In the Kanto region, 500 tons per year of SCCPs were mainly used in oil fluids. In contrast, nearly 200 tons of SCCPs were shipped to the Kansai region for other uses including flame retardant additives and lipid additives for rubber, paint, and adhesives. As shown in Table 1, approximately half of SCCPs were used in oil fluids and the other half for other products. 

Chlorinated paraffins are normally divided into three sub-groups short-chain (SCCP), medium-chain (MCCP) and long-chain (LCCP) chlorinated paraffins. 

Previously, we have screened the literature for relevant biochemical studies on enzyme systems that oxidize medium chain-length alkanes (1). The Pseudomonas strains mentioned in this paper have been studied in varying detail with respect to the enzymology of medium chain-length alkane metabolism. The alkane hydroxylase systems in these strains show a number of differences, such as the apparent absence of rubredoxin in P. aeruginosa 196 Aa (12). On the whole, however, they resemble each other, and the system of P. oleovorans GPol. As an example, we found that the described substrate range of the paraffin hydroxylase of... 

While the 15 halogenated POPs and PAHs are best analysed by GC-ECD and GC-MS, many other organic compounds in current use have similar physical properties and can be expected to partition to sediments in aquatic systems although they may be less persistent. The nony 1 phenol ethylate surfactants have been shown to be relatively persistent in sediments. Analysis by HPLC-triple quad MS permitted the ethoxylates and nonyl phenol to be determined simultaneously (Shang et al., 1999). The short and medium chain chlorinated paraffins, which are complex mixtures of C10-C17 chlorinated n-alkanes, have been determined in sediments by GC-high resolution ECNI MS (Tomy et al., 1997, Tomy Stern, 1999) following conventional extraction and cleannp procedures (Fig. 1). 

Most of the extenders used in plasticised PVC compositions to reduce the amount of plasticiser required are epoxidised compounds, hydrocarbons or chlorohydrocarbons, including a few medium chain length chlorinated paraffins (MCCPs). These last substances typically have 14 to 17 carbon atoms, and unlike their longer chain analogues they are thought to pose a threat to some types of aquatic life. Dover Chemical Corp. is marketing low volatility liquid chlorinated hydrocarbon products under the name Paroil X-10 as extenders to replace part of the plasticiser in PVC. 

Draft EU risk assessments have been circulated for HBCD, TBBA, tris(2-chloroethyl) phosphate and the isopropyl equivalent, tris (2-dichlorethyl) phosphate and 2-2-bis(chloromethyl)trimethylene bis (bis(chloroethyl)phosphate), as well as medium-chain chlorinated paraffins. 

Steam stripping, which is widely used in the regeneration of solvent recovery systems using an activated carbon adsorbent, can be considered as a combination of thermal swing and displacement desorption. Vacuum desorption, which is used in some versions of the Union Carbide IsoSiv process for separation of medium-chain linear paraffins as well as in some air separation systems can be considered as a special case of pressure swing. 

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