Crude coal tar

Crude coal-tar processing is traditionally accomplished by distillation into pitch and a series of distillate oils. Coal-tar pitch is the matenal remaining after all the available distillates are removed The fmal softening point of the coal-tar pitch can be controlled via the distillation conditions. 

Substituted thiophenes, such as 2-iodo-, 2-bromo-, 2 chloromethyl-, and 2-acetyl-thiophene have been obtained by reacting crude, coal-tar benzene with the appropriate reagents. ... 

Coal tar is keratolytic and may have anti-proliferative and anti-inflammatory effects.2 Coal tar products include crude coal tar and tar distillates (liquor carbonis detergens) available as ointments, creams, and shampoos in various strengths. Preparations containing coal tar may precipitate folliculitis,10 will stain clothing, and have an unpleasant odor. They are also photosensitizing and can be combined with UVB phototherapy (Goekermann s regimen) to increase treatment response.19,20... 

Conventional wastewater treatment techniques consist of physical/chemical treatments, including oil separation, dissolved gas flotation, and ammonia distillation (for removal of free cyanides, free sulfides, and ammonia) followed by biological treatment (for organics removal) and residual ammonia nitrification. Almost all residuals from coke-making operations are either recovered as crude byproducts (e.g., as crude coal tar, crude light oil, ammonium sulfate, or other sulfur compounds)... 

The high price of the petroleum product results from its higher quality. The pnee of the crude coal-tar naphthalene is primarily associated with that of o-xylene, its chief competitor as phthalic anhydride feedstock. 

Coke Manufacture By-products. In United States practice, coking of coal is done almost exclusively by the high-temperature (900-1200c C) process, For many years, the major source of the pyridines was the chemical-recovery coke oven, The volatiles produced in the coke oven are only partially condensed. The noncondensed gases are passed through a scrubber (the ammonia saturator) containing sulfuric acid. After removal of crystals (ammonium sulfate), a solution of ammonium sulfate and pyridinium sulfates is obtained and treated with ammonia to liberate and contained pyridine bases (— 70% is pyndine itself), See also Coal Tar and Derivatives. The balance of the pyndine bases is extracted from the crude coal tar. i.e., the condensed, main portion of the volatilization products from coking. The crude tar contains approximately 0,1 -0.2% pyridine bases, Further separation of the pyridines involves a rather complex series of extractions, distillations, and crystallizations. 

COAL TAR SOLUTION USP CRUDE COAL TAR ESTAR IMPERVOTAR LAV LAVATAR PICIS CARBONIS PIXALBOL PIX CARBONIS PIX LITHANTHRACIS POLYTAR BATH SUPERTAH SYNTAR TAR TAR, COAL ZETAR... 

Derivation Contained in the fraction of crude coal tar distillates that boils from 176-182C. 

The Bureau of Mines is a source of many chemical statistics. The monthly Coke and Coal Chemicals report, part of the bureau s Mineral Industry Surveys, contains, in addition to data on oven and beehive coke production, figures on production of ammonium sulfate, ammonia liquor, naphthalene, benzene, toluene, xylene, solvent naphtha, pyridine, crude coal tar, and cresote oil. Sales and end-of-month stock figures are also shown in the report. A useful feature of the report is the year-end supplement which gives year s totals by months. 

Mukhtar H, Asokan P, Das M, et al. 1986. Benzo(a)pyrene diol epoxide-l-DNA adduct formation in the epidermis and lung of sencar mice following topical application of crude coal tar. Cancer Letters 33 287-394. 

Storer JS, DeLeon I, Millikan LE, et al. 1984. Human absorption of crude coal tar products. Arch Dermatol 120 874-877. 

Coal tar preparations reduce itching and inflammation of the skin. These products have been used in combination with topical corticosteroids, as adjuncts so that lower strengths of corticosteroid can be used effectively, and in conjunction with ultraviolet fight therapies. These preparations are available as crude coal tar (1 % to 3%), or liquor carbonis detergens (5% to 20%). At times, coal tar is compounded by pharmacists into various concentrations and sometimes with topical corticosteroids. 

Cyclic crudes, coal tar product of coal tar distillation Cyclic intermediates, made in chemical plants Cyclohexane Diphenylamine Drug dyes, synthetic Dye (cyclic) intermediates Dyes, food synthetic Dyes, synthetic organic Eosine toners Ethylbenzene Hydroquinone Isocyanates Lake red C toners Leather dyes and stains, synthetic... 

Early methods of separation employed such solvents as oleic acid/ crude coal-tar solvent naphtha, light pyridine,5 etc. Based on the selective solution of phenanthrene by the coal-tar naphtha, and of carbazole liy the light pyridine, Clark proposed a complicated scheme for the separation and recovery of all three of these constituents. Recently, organic liquid compounds containing the furan nucleus have been found to have a highly selective solvent action on phenanthrene and carbazole." Thns, furfural while dissolving phenanthrene and carbazole does not have a marked solvent action on anthracene at low temperatures. However, at elevated temperatures it does dissolve anthracene with the result that it is possible... 

Crude coal tar (10, 25, and 100%) in petrolatum was applied to the ear of male Australian albino rabbits (3 per group) 3 times/week for 15 weeks (Kligman and Kligman 1994). Crude coal tar was both comedogenic and carcinogenic at all doses tested (10, 25, or 100%). Tumors developed as early as 1-2 weeks after 3 weeks of treatment with 10% coal tar. The tumors were classified as papillomas, squamous cell carcinomas, keratoacanthomas, and cutaneous horns, and became extremely numerous with longer treatment. 

A coal tar solution (crude coal tar diluted to 20% with ethanol and polysorbate 80) was applied to clinically unaffected skin of three patients with severe atopic dermatitis and six patients with generalized psoriasis (Bickers and Kappas 1978). Another skin area at least 10 cm away was not treated or was treated with 100 mL of the vehicle alone. Twenty-four hours later, a 6-mm punch biopsy was obtained from coal tar treated and control areas and the effect on AHH activity was determined. Application of coal tar to the skin caused induction of cutaneous AHH activity that varied from 2.4- to 5. 4-fold over the enzyme activity in untreated skin areas, suggesting absorption after topical application. 

McGarry GW, Robertson JR. 1989. Scrotal carcinoma following prolonged use of crude coal tar ointment. Br J Urol 63 (2) 211. 

Coal tar preparations are complex and variable mixtures of hydrocarbons that have cytostatic or antimitotic actions. Crude coal tar is the most effective, but few outpatients tolerate the mess and smell. In hospitals, coal tar is often combined with ultraviolet B (UVB) radiation. There are many proprietary preparations, which are more refined and therefore more acceptable to patients, but they are less effective. They are used as a creams, lotions, ointments and bath oils in concentrations from 1 to 12%. 

CRUDE COAL TAR (8007-45-2) Forms explosive mixture with air (flash point 60°-77°F/15°-25°C cc). Violent reaction with strong oxidizers. Incompatible with strong acids, nitrates. 

Crude coal tar, about 5% by weight, a generic name for the resultant toxic, black, oily, viscous distillation liquid or semisolid. 

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