Asphaltic substances

Brown coals yield, on solvent extraction, 10—15% of a material that contains 60—90% light yellow or brown waxy substances. The remainder is a mixture of deep brown resinous and asphaltic substances. The yield may be increased by increasing the pressure during extraction, but this also adds dark colored dispersion products, and the resultant brown coal caimot be briquetted. 

Figure 1. Asphaltic substances in different stages of a process. The size and weight depend on the environment [modified from Ref. 27 and others].

Heavy materials remaining at the bottom are called the bottoms, or residuum, and include such components as heavy fuel oil (see fuel oil) and asphaltic substances (see asphalt). Those fractions taken in liquid form from any level other than the very top or bottom are called sidestream products a product, such as propane, removed in vapor form from the top of the distillation tower is called overhead product. Distillation may take place in two stages first, die lighter fractions—gases, naphtha, and kerosene-are recovered at essentially atmospheric pressure next, the reamining crude is distilled at reduced pressure in a vacuum tower, causing the heavy lube fractions to distill at much lower temperatures than possible at... 

Tests for Bituminous and Semisolid Materials. The most common tests for asphaltic substances are the ductility, penetration, ring-and-ball softening points (E28), and specific-gravity tests. The ductility (D113) of an asphalt is a measure of its capacity to elongate or stretch and is an indication of the ability of the material to flow and thereby mend a rupture in the surface of the material. A briquette of the asphalt... 

Sulfuric acid also removes or dissolves resinous or asphaltic substances that may be present because of poor fractionation, entrainment, or cracking. These materials tend to inhibit the crystallization of wax, and hence acid treatment often raises the pour point. Oxygen compounds, such as naphthenic acids and ketones, and substances such as alcohols mid aldehydes that are formed by high-temperature oxidation are dissolved by sulfuric acid, but when diluted with oil their removal is never complete. Nitrogen bases similar to quinoline or pyridine, which are produced in small quantities during distillation, are easily dissolved in dilute add. 

The rate of action of sulfiuic acid on the various impurities appears to be somewhat as follows (1) nitn en compounds such as amines, amides, and amino adds (2) asphaltic substances (3) olefins (4) aromatics and (5) naphthenic acids. 

Asphalt [8052-42-4] is defined by the American Society for Testing and Materials (ASTM) (1) as a dark brown to black cementitious material in which the predominating constituents are bitumens that occur in nature or are obtained in petroleum processing. Bitumen is a generic term defined by ASTM as a class of black or dark-colored (soHd, semisoHd, or viscous) cementitious substances, natural or manufactured, composed principally of high molecular weight hydrocarbons, of which asphalts, tars, pitches, and asphaltites are typical. 

A variety of other substances can provide the same reaction sulfur yields hydrogen sulfide chlorine yields hydrogen chloride. In some cases, some of the bonds created are quite weak resulting ia, after an iaduction period, a phenomenon termed "fallback." When fallback occurs, usually at a time when the hardened or oxidized asphalt is stored at or near the original processing or reaction temperature, softening of the asphalt is the result (28—31). 

The techniques of paraffin removal and paraffin prevention have been reviewed [810]. In particular, inhibitors for paraffin deposits are copolymers of ethylene with vinylacetate [525-527,1597] or polymers from p-nonylphenyl methacrylate and p-dodecylphenyl methacrylate [773]. These materials lower the pour point of the oil. It has been shown that for oils which differ in the content of n-paraffins and asphalt-resinous substances, it is necessary to use blends of copolymers of different compositions and molecular weights to obtain optimal efficiency. Polyacrylamide and wastes from the production of glycerol with a concentration of 400 mg/liter of oil have also been claimed to be effective as paraffin inhibitors [536]. 

The Babylonians and Assyrians cemented stone slabs as well as bricks with bitumen (which is sometimes also referred to as asphalt), a mixture of a black or brown natural organic material with a pitchy luster and comminuted mineral. Bitumen is a thermoplastic solid material when heated above 50°C, it softens and becomes a thick, viscous liquid that reverts to a solid on cooling. It is composed of a natural mixture of hydrocarbons (organic substances composed of carbon, hydrogen, and oxygen) that occurs in natural... 

Asphalt is a bituminous substance that is found in natural deposits or as the residual of in petroleum or coal tar refining processes. It has a black or brownish-black color and pitchy luster. It is cement-like in... 

For example, treating petroleum distillates with sulfuric acid is generally applied to dissolve unstable or colored substances and sulfur compounds as well as to precipitate asphaltic materials. When drastic conditions are employed, as in the treatment of lubricating fractions with large amounts of concentrated acid or when fuming acid is used in the manufacture of white oils, considerable quantities of petroleum sulfonic acids are formed ... 

The inhabitants of ancient Nineveh used an asphaltic mortar prepared from partially evaporated petroleum (8). In some translations of the Old Testament, this substance is called pitch or slime. When Noah built the ark, he was told to pitch it within and without with pitch. For building the Tower of Babel, Noah s descendants had brick for stone, and slime had they for mortar (9). 

This body is produced, together with numerous other com pounds of a like nature, by the destructive distillation of bog head cotd and similar substances. It is also found in petro leum and asphalt. If chlorine be passed into melted paraffin, the latter is slowly attacked, hydroohloric acid being evolved. In this reaction paraffin resembles the hydrides of the monad radicals, and differs ffom the dyad radiesds, to which dass it was formerly considered to belong. In the formula C shh-s for paraffin, the value of has not yet been satis ctorily determined in fact it is probable that. several distinct hy des of the class now under consideration are confounded under this name. 

Human exposure to ethylbenzene occms mainly via inhalation of vapour and/or mist and, to a smaller extent, by dermal contact or ingestion. Ethylbenzene is produced by the incomplete combustion of natural materials, making it a component of smoke from forest fires and cigarettes. It is also a constituent of asphalt and naphtha (Agency for Toxic Substances and Disease Registry, 1997a WHO, 1996a). 

Asphalt Hydrocarbon material ranging in consistency from heavy liquid to a solid. Most common source is residue left after fractional distillation of crude oils used primarily for surfacing roads. Asphyxia Suffocation from lack of oxygen. Chemical asphyxia is produced by a substance, such as carbon monoxide, that combines with hemoglobin to reduce die blood s capacity to transport oxygen. Simple asphyxia is the result of exposure to a substance, such as carbon dioxide, that displaces oxygen. 

Noteworthy among the few reports in the literature on this subject is the work of Andersen, Bills, Mishuck, Moe and Schultz [3] on the mechanism of combustion of a mixture of 75% NH4C104 and 25% polyester with styrene. The work of Gro-dzinski [18] who investigated the thermal decomposition of the mixtures of various combustible substances with potassium perchlorate in a ratio of 20/80 by weight, is also of great interest. The combustible ingredients include asphalt and polyester resin from unsaturated (maleic) or saturated acids. 

In the noble metals and in many minerals the elements were believed to be so well combined that heat could not separate them. Other minerals, as sulphur, orpiment, asphalt, etc., when heated in the air are partly broken down, the aerial element, not being so firmly united to the earth, being driven off as vapor and mingling with the particles of the atmosphere. This process was interpreted by the Greek alchemists and their Arabian successors as the separation of the spirit from the body, and such substances as were volatilized or burned with formation of gaseous products—as sulphur, arsenic (sulphides), sal ammoniac, quicksilver—were called spirits, while the metals and minerals which, when heated in the air did not volatilize nor disappear in gaseous products, were called bodies (corpora). 

Bituminous Substances. The distribution of hydrocarbons and other bitumens in some of the Paleozoic rocks of the area is shown in Tables I and II, the latter summarized after Swain (7). The presumed saturated hydrocarbons of the Ordovician, Silurian and Lower Devonian samples are measurably less than in the Middle and Upper Devonian samples. The presumed aromatic hydrocarbons are not as well differentiated. The pyridine-plus-methanol-eluted chromatographic fractions, arbitrarily taken as asphaltic material, also appear, like the aromatic fractions, to be controlled more by local variations than by geologic age. 

The possibility of low temperature generation of protoanthraxolite has been confirmed experimentally by Berl (3) and Schuhmacher et al. (33), who produced asphaltic and coaly substances from pure carbohydrates by heating in a weakly alkaline solution at temperatures between 230° and 340°C. Such changes evidently take place spontaneously over long time periods even in the absence of such heat. 

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