Coal tar distillates

Other Organic Processes. Solvent extraction has found appHcation in the coal-tar industry for many years, as for example in the recovery of phenols from coal-tar distillates by washing with caustic soda solution. Solvent extraction of fatty and resimic acid from tall oil has been reported (250). Dissociation extraction is used to separate y -cresol fromT -cresol (251) and 2,4-x5lenol from 2,5-x5lenol (252). Solvent extraction can play a role in the direct manufacture of chemicals from coal (253) (see Eeedstocks, coal chemicals). 

The industrial source of indole has been isolation from coal-tar distillate (7). Several patents for the manufacture of indole have been issued with aniline and ethylene glycol (8), aniline and ethylene oxide (9), 2-ethy1ani1ine (10), and /V-ethy1ani1ine (11) as the starting materials. 

Vinyl carbazole is obtained by reacting carbazole, readily available as a byproduct of coal tar distillation, with acetylene in the presence of a catalyst and solvent under pressure Figure 17.7). 

A number of other phenols obtained from coal tar distillates are used in the manufacture of phenolic resins. Of these the cresols are the most important... 

The cresols occur in cresylic acid, a mixture of the three cresols together with some xylenols and neutral oils, obtained from coal tar distillates. Only the /n-cresol has the three reactive positions necessary to give cross-linked resins and so this is normally the desired material. The o-isomer is easily removed by distillation but separation of the close-boiling m- and p-isomers is difficult and so mixtures of these two isomers are used in practice. 

Other higher boiling phenolic bodies obtainable from coal tar distillates are sometimes used in the manufacture of oil-soluble resins. Mention may also be made of cashew nut shell liquid which contains phenolic bodies and which is used in certain specialised applications. 

Coal tar distillation Vehicle exhausts Petrochemicals Pesticides Herbicides Pigment and dye Pesticide and herbicide production... 

The technical method for obtaining phenol is by shaking out with caustic soda the middle oil of the coal-tar distill ate,. after some of the naphthalene has crystallised out. The phenol dis-soKes m the alkali, and is then lemoved fiom insoluble oils. The alkaline liquid is acidified, the phenol separated, distilled, and finally purified by freezing. 

When coal is heated to a high temperature in the absence of air, it undergoes decomposition volatile products (coal gas and coal tar) distill away and a residue called coke remains. Coke is a valuable industrial material which finds its chief use in the reduction of iron ore (iron oxide) to iron for the manufacture of steel. Coke is essentially carbon that still contains the mineral substances that are present in all coals (and form the ash that results when coal or coke is burned). 

Aromatic hydrocarbons G L Benzene Toluene Xylene Coal tar distillation Vehicle exhauks Petrochemicals Pesticides Herbicides... 

Figure 1.30 Chemical products from coal tar distillation.

Coumarone, indene from coumarone, indene, coal tar distillate NaY Toluene [12]... 

Benzene is produced from petroleum refining, coal tar distillation, coal processing, and coal coking (quoted, Verschueren, 1983). A high-temperature coal tar contained benzene at an average concentration of 0.12 wt % (McNeil, 1983). 

How could you remove unsaturated hydrocarbons from petroleum or coal tar distillates ... 

In a commercially useful reaction, sulfuric acid can be used to sulfonate thiophene at room temperature Benzene is not attacked under these conditions, and needs a reaction with oleum at 60 °C before it is sulfonated. Thiophene-2-sulfonic acid, formed in this way, dissolves in dilute alkali, allowing thiophene in coal tar distillate to be easily removed from benzene. Thiophene can be generated from its sulfonic acid by heating the latter in steam. 

No information was located regarding 2,3-benzofuran in surface water in the United States. 2,3-Benzofuran was detected in contaminated groundwater at a coal-tar distillation and wood-preserving facility in Minnesota (Rostad et al. 1985). 

Individuals occupationally exposed to coal tars or the naphtha fraction of coal-tar distillate have potentially high exposure to 2,3-benzofuran. Persons living near industrial sources or hazardous waste sites contaminated with 2,3-benzofuran may be exposed to 2,3-benzofuran. There are insufficient data to identify any other populations with potentially high exposure to this compound. 

Coal-tar distillates -quinoline from [QUINOLINES AND ISOQUINOLINES] (Vol 20)... 

N 8.38% col lfts or pltlts(from xylol or by subln), mp 245°, bp 355°, d 1.10 at 18°, vap press 400mm at 323°. Carbazole is one of the principal ingredients of the anthracene fraction of coal tar distilling between 320 and 360° it can be separated from other constituents by various methods, one of which is fusion with KOH and separation of the resulting deriv. Various methods of separating or preparing carbazole are described in Refs 1,5,7,9a,10,11,16 others... 

Polynuclear aromatic hydrocarbons (PAH) (a coal-tar distillate fraction) — Solvent extraction and determination by HPLC, GC-FID or GC/MS enzyme immunoassay testing may be applied for semiquantitive determination. 

MW 78.12 CAS [71-43-2] occurs in gasoline and coal-tar distillation products used as a solvent and in organic synthesis colorless liquid with characteristic odor boils at 80.1°C freezes at 5.5°C vapor pressure 76 torr at 20°C density 0.88 g/L slightly soluble in water (1.78 g/L) readily miscible with organic solvents toxic and carcinogenic flammable. 

MW 92.15 CAS [108-88-3] occurs in gasoline, petroleum solvents, and coal-tar distillates used as a solvent and in many organic syntheses colorless liquid with a characteristic aromatic odor boils at 110.7°C freezes at -95°C vapor pressure 22 torr at 20°C density 0.866 g/mL at 20°C slightly soluble in water (0.63 g/L at 25°C) readily miscible with organic solvents. 

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