Aromatic hydrocarbons extraction

The determination of the strength of the Lewis acids MF , has been carried out in various solvents using the conventional methods. Numerous techniques have been applied conductivity measurements, cryoscopy, aromatic hydrocarbon extraction,53,84 solubility measurements,85-87 kinetic parameters determinations,52,88,89 electroanalytical techniques (hydrogen electrode),90-93 quinones systems as pH indicators,94-97 or other electrochemical systems,98 99 IR,100,101 and acidity function (//,) determinations with UV-visible spectroscopy,8 9 14 19 102-105 or with NMR spectros-copy.20-22,44-46,106-108 Gas-phase measurements are also available.109-111 Comparison of the results obtained by different methods shows large discrepancies (Table 1.2). 

Cyanogen Compounds Mix 5 g of sample with 50 mL of water and 2 g of tartaric acid, and distill the mixture, collecting 25 mL of distillate below the surface of a mixture of 2 mL of 1 N sodium hydroxide and 10 mL of water contained in a small flask placed in an ice bath. Dilute the distillate to 50 mL with water, and mix. Add 12 drops of ferrous sulfate TS to 25 mL of the diluted distillate, heat almost to boiling, cool, and add 1 mL of hydrochloric acid. No blue color is produced. Higher Aromatic Hydrocarbons Extract 1 g of sample with 12 mL of cyclohexane in a continuous-extraction apparatus for 2 h. Place the extract in a Nessler tube and a solution of 100 (xg of quinine sulfate in 1000 mL of 0.1 N sulfuric acid in a matching Nessler tube. The extract shows no more color or fluorescence than does the solution when observed under ultraviolet light. 

Figure 1. Capillary gas chromatogram of aromatic hydrocarbons extracted from a seawater suspension...

Ai3-18365 Carbonic acid, cyclic ethylene ester CCRIS 293 Cyclic ethylene carbonate Dioxolone-2 EINECS 202-510-0 Ethylene carbonate Ethylene carbonic acid Ethylene glycol carbonate Ethylene glycol, cyclic carbonate Ethylenester kyseiiny uhlicite Glycol carbonate HSDB 6803 NSC 11801 Texacat EC. Solvent for organic and Inorganic material ERA Rule 66 exempt also used as reactant and plasticizer in fibers and textiles, plastics and resins, aromatic hydrocarbon extraction, electrolytes, hydraulic brake fluids. Plates mp = 36.4" bp = 248° = 1,3214 freely soluble in H2O,... 

Figure 29 8 illustrates the separation of polycyclic aromatic hydrocarbons extracted from a carbon black, Detection was by fluorescence excited at two differeni wavelengths. Note the selectivity provided by this technique, The chromatogram was obtained b> using a 40 m X. SO pm inside-diameter capillary coated with a 0,25-pm film of S0% phenylpolysiloxane. The mobile phase was pentane at 2l(rc. and the following pro-gram was used initial mobile-phase density held at... 

Chromatogram of an Aromatic Hydrocarbon Extract from Coal Obtained from a High Efficiency Small Bore Column... 

Chem. Descrip. Propylene carbonate CAS m32-7 EINECS/ELINCS 20S 572-1 Uses Solvent, reactant, plastidzer for fibers, textiles, dyeing, plastics and resins, gas treating, aromatic hydrocarbon extraction, metal extraction, surf, coatings (paints, varnishes, adhesives, plastics, epoxies, mastics), foundry sand binder, lubricants, electrolytes, cosmetics (polar additive for montmorillonite or bentonite clay gellants) fire extinguishing compds. antifoam for antifreeze hydraulic brake fluids as plating medium... 

A method ) has been recommended for the determination of benzene in the presence of its homologues. It is based on nitration of a mixture of aromatic hydrocarbons, extraction with ether of the nitro-compounds formed from the reaction mixture, evaporation of the solvent, oxidation with chromic acid and dissolution of the residue in acetic acid. 

Edeleanu process An extraction process utilizing liquid sulphur dioxide for the removal of aromatic hydrocarbons and polar molecules from petroleum fractions. 

Hydrocarbons are divided into two mam classes aliphatic and aromatic This classifi cation dates from the nineteenth century when organic chemistry was devoted almost entirely to the study of materials from natural sources and terms were coined that reflected a substance s origin Two sources were fats and oils and the word aliphatic was derived from the Greek word aleiphar meaning ( fat ) Aromatic hydrocarbons irre spective of their own odor were typically obtained by chemical treatment of pleasant smelling plant extracts... 

Uses. The principal use of adiponitrile is for hydrogenation to hexamethylene diamine leading to nylon-6,6. However, as a result of BASE s new adiponitrile-to-caprolactam process, a significant fraction of ADN produced may find its way into nylon-6 production. Adipoquanamine, which is prepared by the reaction of adiponitrile with dicyandiamide [461-58-5] (cyanoguanidine), may have uses in melamine—urea amino resins (qv) (see "Benzonitrile, Uses"). Its typical Hquid nitrile properties suggest its use as an extractant for aromatic hydrocarbons. 

Typical nonsieve, polar adsorbents are siUca gel and activated alumina. Kquilihrium data have been pubUshed on many systems (11—16,46,47). The order of affinity for various chemical species is saturated hydrocarbons < aromatic hydrocarbons = halogenated hydrocarbons < ethers = esters = ketones < amines = alcohols < carboxylic acids. In general, the selectivities are parallel to those obtained by the use of selective polar solvents in hydrocarbon systems, even the magnitudes are similar. Consequendy, the commercial use of these adsorbents must compete with solvent-extraction techniques. 

Caprolactam Extraction. A high degree of purification is necessary for fiber-grade caprolactam, the monomer for nylon-6 (see Polyamides). Cmde aqueous caprolactam is purified by solvent extractions using aromatic hydrocarbons such as toluene as the solvent (233). Many of the well-known types of column contactors have been used a detailed description of the process is available (234). 

Another use is in various extraction and absorption processes for the purification of acetylene or butadiene and for separation of aHphatic hydrocarbons, which have limited solubiHty in DMF, from aromatic hydrocarbons. DMF has also been used to recover CO2 from flue gases. Because of the high solubiHty of SO2 iu DMF, this method can even be used for exhaust streams from processes using high sulfur fuels. The CO2 is not contaminated with sulfur-containing impurities, which are recovered from the DMF in a separate step (29). 

Aromatic Hydrocarbons. Sulfolane is used principally as a solvent for extraction of benzene, toluene, and xylene from mixtures containing aHphatic hydrocarbons (33—37). The sulfolane process was introduced in 1959 by SheU Development Company, and that process is Hcensed by Universal OH Products. A sulfolane extraction process is also Hcensed by the Atlantic Richfield Company. In 1994, worldwide consumption was estimated at ca 6974 t/yr of sulfolane for 137 sulfolane extraction units (see Bix processes Extraction, liquid-liquid Xylenes and ethylbenzene). 

Extraction Solvent. Dimethyl sulfoxide is immiscible with alkanes but is a good solvent for most unsaturated and polar compounds. Thus, it can be used to separate olefins from paraffins (93). It is used in the Institute Fransais du Pntrole (IFF) process for extracting aromatic hydrocarbons from refinery streams (94). It is also used in the analytical procedure for determining polynuclear hydrocarbons in food additives (qv) of petroleum origin (95). 

Sulfur dioxide acts as a dienophile ia the Diels-Alder reaction with many dienes (253,254) and this reaction is conducted on a commercial scale with butadiene. The initial adduct, sulfolene [77-79-2] is hydrogenated to a solvent, sulfolane [126-33-0] which is useful for selective extraction of aromatic hydrocarbons from... 

Several solvent uses have been proposed. Dimethyl sulfate has been used as a solvent for the study of Lewis acid—aromatic hydrocarbon complexes (148). It also is effective as an extraction solvent to separate phosphoms haUde—hydrocarbon mixtures and aromatic hydrocarbons from aUphatics, and it acts as an electrolyte in electroplating iron (149—152). The toxicity of dimethyl sulfate precludes its use as a general-purpose solvent. 

Low temperature tars contain 30—35 wt % non aromatic hydrocarbons, ca 30% of caustic-extractable phenols in the distillate oils, and 40—50% of aromatic hydrocarbons. The latter usually contain one or more alkyl substituent groups. On atmospheric distillation, coke-oven tars yield 55—60% pitch, whereas CVR tars give 40—50% pitch. The pitch yield from low temperature tars is in the 26—30% range. 

The performance of microwave-assisted decomposition of most difficult samples of organic and inorganic natures in combination with the microwave-assisted solution preconcentration is illustrated by sample preparation of carbon-containing matrices followed by atomic spectroscopy determination of noble metals. Microwave-assisted extraction of most dangerous contaminants, in particular, pesticides and polycyclic aromatic hydrocarbons, from soils have been developed and successfully used in combination with polarization fluoroimmunoassay (FPIA) and fluorescence detection. 

ACID-BASED SURFACTANT CLOUD POINT EXTRACTION AND PRECONCENTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS PRIOR TO FLUORESCENCE DETERMINATION... 

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