Constituents in Oil

Lightweight, anticorrosive metal that forms few compounds one of its isotopes is useful as a tracer of specific constituents in oil refining. 

Thujane monoterpenes are based on the bicyclic (G3 C5) monoterpene thujane and include umbellone (thujan-2-one) and the neuroactives a-thujone and 3-thujone (thujan-3-one isomers) that can cause convulsions. Thujones are GABA(A) receptor antagonists and are the active constituents in oil of wormwood from Artemisia absinthium (Asteraceae) used in the alcoholic drink absinthe that was eventually banned because of its deleterious neurotoxic effects. 

Figure 11.5 shows that the functional group compositional analysis of the pyrolysis oil/waxes derived from the fixed-bed pyrolysis of PVC, PS and PET is very different from the polyalkene plastic pyrolysis oil/waxes. The spectra of the PVC pyrolysis oil/wax shows that the characteristic peaks of alkanes and alkenes are present as described for the polyalkene plastics. Since the PVC plastic polymer is based on a similar backbone structure to the polyalkene plastics, a similar degradation product oil/wax composition may be expected. However, the spectra for PVC in Figure 11.5 show that there are additional peaks in the region of 675-900 cm and 1575-1625 cm The presence of these peaks indicates the presence of mono-aromatic, polycyclic aromatic and substituted aromatic groups. Benzene has been identified as a major constituent in oils derived from the pyrolysis of PVC whilst other aromatic compounds identified included alkylated benzenes and naphthalene and other polycyclic aromatic hydrocarbons [19, 32, 39]... 

The bromine number is the number of grams of bromine that will react with 100 g of the sample under the test conditions and is better suited to the determination of unsaturated constituents in oil (ASTM D-875, ASTM D-1159, ASTM D-2710, IP 130). The magnitude of the bromine number is used as a measure of aliphatic unsaturation in petroleum products. In the test, a known weight of the sample dissolved in a specified solvent maintained at 0-5°C (32-41 °F) is titrated with standard bromide-bromate solution. Determination of the end point is method dependent. 

Nigam I C, Levi L 1963 Essential oils and their constituents. XIX. Detection of new trace constituents in oil of rosewood. Perfum Essent Oil Rec 54 814-816... 

Sterols. Sterols (4) are tetracycHc compounds derived biologically from terpenes. They are fat-soluble and therefore are found in small quantities in fats and oils. Cholesterol [57-88-5] (4a) is a common constituent in animal fats such as lard, tallow, and butterfat. The hydroxyl group can be free or esterified with a fatty acid. 

Colloidal State. The principal outcome of many of the composition studies has been the delineation of the asphalt system as a colloidal system at ambient or normal service conditions. This particular concept was proposed in 1924 and described the system as an oil medium in which the asphaltene fraction was dispersed. The transition from a coUoid to a Newtonian Hquid is dependent on temperature, hardness, shear rate, chemical nature, etc. At normal service temperatures asphalt is viscoelastic, and viscous at higher temperatures. The disperse phase is a micelle composed of the molecular species that make up the asphaltenes and the higher molecular weight aromatic components of the petrolenes or the maltenes (ie, the nonasphaltene components). Complete peptization of the micelle seems probable if the system contains sufficient aromatic constituents, in relation to the concentration of asphaltenes, to allow the asphaltenes to remain in the dispersed phase. 

There are a number of metallic compounds of chromium that ate used either as the compound itself or as metallurgical constituents in Cr-beating alloys. Trichromium dicarbide [12012-35-0] is important as a wear-resistant gauge material chromium botide(l 1) [12006-79-0] CrB, for oil well drilling ... 

Essential oils are obtained from fmits and flowers (61,62). Volatile esters of short- and medium-chain carboxyHc acids or aromatic carboxyHc acids with short- and medium-chain alcohols are primary constituents of essential oils, eg, ethyl acetate in wines, brandy, and in fmits such as pineapple ben2yl acetate in jasmine and gardenia methyl saHcylate in oils of wintergreen and sweet birch. Most of these naturally occurring esters in essential oils have pleasant odors, and either they or their synthetic counterparts are used in the confectionery, beverage, perfume, cosmetic, and soap industries (see Oils, essential). 

Air emissions from refineries include fugitive emissions of the volatile constituents in crude oil and its fractions, emissions from the burning of fuels in process heaters, and emissions from the various refinery processes themselves. Fugitive emissions occur throughout refmeries and arise from the thousands of potential fugitive emission sources such as valves, pumps, tanks, pressure relief valves, flanges, etc. 

Basically, a gas absorption tower is a unit in which the desirable light ends components are recovered from the gas feed by dissolving them in a liquid passing through the tower countercurrently to the gas. The liquid absorbent is called lean, oil, and it usually consists of a hydrocarbon fraction in the gasoline boiling range. After the absorption step, the liquid which now contains the desired constituents in solution is referred to as fat oil. A similarly descriptive nomenclature is applied to the gas, which is referred to as wet gas when it enters the tower and as dry gas when it leaves the absorber. 

Phenyl i-ibyl alcohol has recentlv beeii shown to he a normal constituent of otto of rose, but it appears to he mostly, if not entirely lust or dsstroveil by the Bulgarian method of rlisiillation. Nerol ifi also present in small amount as well as, probably, faroesol. a sesquiterpene alcohol CijH.,0, present in oil of cassie flowers. Eiigeuol, linalol, and nonyliu aldehyde arc also present in traces. 

Linalol is found very widely distributed in essential oils. It forms the principal constituent, in the free state, of oil of linaloe, and the chief odorous constituent, in the form of esters, in bergamot and lavender oils. It is also found in ylang-ylang, rose, champaca leaf, cinnamon, petit-grain, spike, geranium, lemon, spearmint, and numerous. other essential oils. 

This ketone occurs in eucalyptus oils derived from a particular group of trees, the leaves of which have the venation characteristic of species yielding phellandrene-bearing oils. It follows the general rule for all constituents in eucalyptus oils, increasing in amount until the... 

Pinocamphone, Cj Hj O, is the principal constituent of oil of hyssop, in which it occurs in its laevo-rotatory variety. It is a saturated ketone having the constitution —... 

The sulphuric acid, used to acidulate before distillation, may be advantageously replaced by phosphoric acid. This modification, whilst in many cases not absolutely essential, is desirable on account of the fact that sulphuric acid is liable to become reduced by certain constituents of oils, particularly of old oils, which frequently contain substances of a resinous nature. In such cases the volatile acid products of the reduction pass over along with the true acids of the oil undergoing examination. 

Turpentine Oil.—This is readily recognised in oils which contain no pinene, as this is the main constituent of turpentine oil. It is usually found in the first distillates, and generally reduces the specific gravity and effects the solubility and optical rotation. Its presence is proved by the formation of pinene hydrochloride (melting-point 125°) and the nitro-sochloride (melting-point 103°). If pinene is a constituent of the oil itself, the addition of turpentine can only be proved by comparison with an authentic sample. 

Figure 2-77 shows how the weight distributions of the different molecular types vary during the fractional distillation of a naphthenic crude oil. Saturated aliphatic hydrocarbons (i.e., paraffins and naphthenes) are the predominant constituents in the light gasoline fraction. As the boiling point is raised, the paraffin content decreases, and the NSO content increases continuously. About 75 wt% of tbe residuum is composed of aromatics and NSO compounds. 

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