Hydrocarbons, hydrocarbon mercury compounds

In saline sediments aliphatic and polyaromatic hydrocarbons carbohydrates haloaromatic compounds chlorophenols basic nitrogen compounds various organosulphur compounds mixtures of organic compounds total sulphur arsenic and organic compounds of lead, mercury and tin. ... 

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), Pentachlorophenol m(PCP, mercury and organic mercury compounds, cadmium, lead and organic lead compounds, brominated flame retardants), nonylphenol/ethoxylates (NP, NPEs) amongst others in the OSPAR Strategy with regard to Hazardous Substances... 

Polychlorinated dibenzodioxins (PCDDs) Polychlorinated dibenzofurans (PCDFs) Polychlorinated biphenyls (PCBs) Polyaromatic hydrocarbons (PAHs) Pentachlorophenol Short chain chlorinated paraffins Hexachlorocyclohexane isomers Mercury and organic mercury compounds Cadmium... 

Description Three RAM processes are available to remove arsenic (RAM I) arsenic, mercury and lead (RAM II) and arsenic, mercury and sulfur from liquid hydrocarbons (RAM III). Described above is the RAM II process. Feed is heated by exchange with reactor effluent and steam (1). It is then hydrolyzed in the first catalytic reactor (2) in which organometallic mercury compounds are converted to elemental mercury, and organic arsenic compounds are converted to arsenic-metal complexes and trapped in the bed. Lead, if any, is also trapped on the bed. The second reactor (3) contains a specific mercury-trapping mass. There is no release of the contaminants to the environment, and spent catalyst and trapping material can be disposed of in an environmentally acceptable manner. 

SAFETY PROFILE Poison by intraperitoneal route. See also MERCURY COMPOUNDS, NITRO COMPOUNDS of AROMATIC HYDROCARBONS. 

The catalytic effect of high-overvoltage electrode materials may be exemplified by the reduction of ketones in hydrochloric acid at mercury and cadmium or amalgamated zinc electrodes at mercury, alcohols, pinacols, organic mercury compounds, or sometimes hydrocarbons may be formed (Chapter 10), whereas at cadmium, the reaction is to some degree analogous to the Clemmensen reduction and yields methylene compounds [114]. 

The removal of all mercury species from liquid hydrocarbon feedstocks (raw condensates, crude oil, condensate cuts) is difficult since the majority of the mercury in these feeds is in organometallic form. Most of the time the presence of mercury is associated with the injection of natural gas condensates into the steam cracker. These heavy condensates can contain very high levels of mercury compounds and these mercury species are spread over all the cuts according the following distribution 0-5 % C2, 30-35 % C3, 55-65% C4, 5-10% others cuts. 

Table 1 Approximate distribution and abundance of mercury compounds in hydrocarbons...

Extracts were methylated to facilitate the analysis of fatty acids (results not reported In this paper). Derlvatlzed extracts were subjected to preparatory thin layer chromatography (TLC) on Analtech silica GHL plates the elution solvent was 6.6Z diethyl ether/hexane. Bands were visualized by exposing the plates to Iodine vapor. Saturated hydrocarbons and chlorinated compounds were collected together In a broad band directly beneath the solvent front. These hydrocarbon/PCB fractions were dissolved In hexane and treated with metallic mercury to remove elemental sulfur prior to gas chromatographic analysis. 

Organic mercury compounds are discussed in three main groups, according to the nature of the hydrocarbon or substituted hydrocarbon radical. 

AMMONIA GAS (7664-41-7) Anhydrous, compressed gas or cryogenic liquid. Difficult to ignite, but can detonate in confined spaces in fire. Reacts violently with strong oxidizers, acids (nitric, hydrochloric, sulfuric, picric, hydrobromic, hydrochlorous, etc.). Shock-, temperature-, and pressure-sensitive compounds are formed with antimony, chlorine, germanium compounds, halogens, heavy metals, hydrocarbons, mercury oxide, silver compounds (azides, chlorides, nitrates, oxides). Fire and/or explosions may be caused by contact with acetaldehyde, acrolein, aldehydes, alkylene oxides, amides, antimony, boron, boron halides. 

The RAM II process (Fig. 18.31) developed by IFF is ideally suited for simultaneous removal of arsenic, mercury and lead from contaminated feedstocks, upstream of aromatics complexes or steam-cracking units. Typical results are excellent, less than 3 ppb of each contaminant in the process effluent as threshold limit for analysis, 1 ppb of each as expectation. Mercury removal from a HC cut is not as simple as the same operation from a gas or LPG feed. The very nature of the mercury compounds to be found in such a cut requires a two-step process in which the organo-mercuric species are decomposed into hydrocarbons and... 

Other elements which react satisfactorily with dialkyl and diaryl mercury compounds include the alkali metals, the alkaline earths, Al, Ga, Sn, Pb, Sb, Bi, Se and Te (see Chapters 3, 4). In some cases the formation of a metal amalgam assists the reaction. The transition elements, when they react, give metallic mercury and a mixture of hydrocarbons. An unstable organotransition metal species may be formed initially, only to decompose. The reactions,... 

Hydrocarbon A has the formula C9HI2 and absorbs 3 equivalents of H to yield B, C9H]g, when hydrogenated over a Pd/C catalyst. On treatment of A with aqueous H2S04 in the presence of mercury(d), two isomeric ketones, C and D, are produced. Oxidation of A with KMn04 gives a mixture of acetic acid (CH3C02H) and the tricarboxylic acid E. Propose structures for compounds A-D, and write the reactions. 

The next eight chapters will be devoted to the ecotoxicology of groups of compounds that have caused concern on account of their real or perceived environmental effects and have been studied both in the laboratory and in the field. These are predominantly compounds produced by humans. However, a few of them, for example, methyl mercury, methyl arsenic, and polycyclic aromatic hydrocarbons (PAHs), are also naturally occurring. In this latter case, there can be difficulty in distinguishing between human and natural sources of harmful chemicals. 

Asbestos fibers, dissolved chlorine, dissolved hydrogen, sodium chloride lead, chlorinated organic compound Lead, chlorinated organic compound, such as methylene chloride and hexachlorinated benzenes Mercury, asbestos fibers, chlorinated hydrocarbons Hypochlorite... 

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