Petroleum Oxygen-containing hydrocarbon derivatives

In addition to hydrocarbons, petroleum also contains compounds that consist of nitrogen, oxygen, and sulfur (in the minority) as well as trace amounts of metals such as vanadium, nickel, iron, and copper. Porphyrins, the major organometaUic compounds present in petroleum, are large, complex cyclic carbon structures derived from chlorophyll and characterized by the ability to contain a central metal atom (trace metals are commonly found within these compounds). 

Ci uuc oil—complex, naturally occurring fluid mixture of petroleum hydrocarbons, yellow to black in color, and also containing small amounts of oxygen, nitrogen, and sulfur derivatives and other impurities. Crude oil was formed by the action of bacteria, heat, and pressure on ancient plant and animal remains, and is usually found in layers of porous rock such as limestone or sandstone, capped by an impervious layer of shale or clay that traps the oil (see reservoir). Crude oil varies in appearance and hydrocarbon composition depending on the locality where it occurs, some crudes being predominately naphthenic, some paraffinic, and others asphaltic. Crude is refined to yield petroleum products. See distillation, hydrocarbon, sour crude, sweet crude, asphalt, naphthene, paraffin. 

The sulfur content of petroleum containing these compounds is usually quite low but it can be as high as 6% of the total. The more stable oxygen derivatives of hydrocarbons, such as the paraffinic acids, ketones, and phenols (Eq. 18.7), also occur in crude oils. 

Petroleum chemicals are synthetic organic chemicals including hydrocarbons and derivatives containing oxygen, nitrogen, sulfur, the halogens, synthesized from fractions of crude petroleum or natural gas hydrocarbon components (70). 

Petroleum is the mixture of gaseous, liquid, and solid hydrocarbons (although the term is often restricted to the non-gases) derived from chemical reactions on prehistoric animal and vegetable matter which occurs as reservoirs in sedimentary rocks from which it is extracted. Petroleum (8002-05-9) syn. crude oil or petroleum oil also contains inorganics such as compounds of sulphur, nitrogen, oxygen, metals, etc. 

Condensable liquid products and tars will also be prodnced these materials are noted for their high aromatic character and high oxygen content (predominantly phenolic oxygen). By analogy with petroleum-derived products, coal products also contain satnrated (straight- and branched-chain) material, olefins, aromatics, and naphthenes (satnrated hydrocarbon ring systems) with special emphasis on the latter two structnral types. 

Oils are derived from petroleum (mineral oils) or fi-om plants or animals (fixed oils). Mineral oils are classified according to soince (type of crude), refining process (distillate or residual), and commercial use. The commercial mineral oil base products consist mainly of saturated hydrocarbons (even though naphthene-base crudes are predominantly unsaturated) in the form of chain or ring molecules that are chemically inactive and do not have polar heads. These commercial products may or may not contain waxes, volatile compounds, fixed oils, and special-purpose additives. Fixed oils and fats differ from mineral oils in that they consist of an alcohol radical and a fatty-acid radical, can be reacted with an alkali (sodium hydroxide or potassium hydroxide, for example) to form glycerin or soap, cannot be distilled without decomposing, and contain 9 to 12.5% oxygen. All fixed oils are insoluble in water and, except for castor oil, are insoluble in alcohol at room temperature. 

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