Hydrocarbons classifying

The bicyclic terpene hydrocarbons classified in this report as the bomane group (bicycloQ2.2.1 heptane type), but currently called the camphane group in terpene literature, are more numerous and have many more important derivatives (especially the camphors) than the other three fundamental bicyclic types — the thujane, carane, and pinane groups — already discussed. As would be expected, a greater variety in the arrangement of substituents and double bonds and in the number of substituents is found. 

Figure 13.1 Hydrocarbons classified for discussion of their toxicological chemistry.

Limonene is a colourless liquid hydrocarbon classified as a cyclic terpene. The isomer found in orange peel is (+)-limonene (Figure 20.71). It is thought that its high abundance in this part of the fruit is connected with the fact that it is an insecticide. As well as its smell, limonene also contributes to the flavour of the fruit and as such has been used as a food additive for many years. Limonene is an important precursor in the biosynthesis of (-)-menthol, which is the major component of mint and the molecule responsible for the herb s refreshing taste. It is used in chemical synthesis as a precursor to carvone and as a renewably based solvent in cleaning products. It is readily prepared in the laboratory by steam distillation of the zest of an orange or lemon. 

In France, bitumen belong to a category of products called "hydrocarbon binders . They are defined and classified in the French Standard, NF T 65000. The hydrocarbon binders comprise ... 

Schemes for classifying surfactants are based upon physical properties or upon functionality. Charge is tire most prevalent physical property used in classifying surfactants. Surfactants are charged or uncharged, ionic or nonionic. Charged surfactants are furtlier classified as to whetlier tire amphipatliic portion is anionic, cationic or zwitterionic. Anotlier physical classification scheme is based upon overall size and molecular weight. Copolymeric nonionic surfactants may reach sizes corresponding to 10 000-20 000 Daltons. Physical state is anotlier important physical property, as surfactants may be obtained as crystalline solids, amoriDhous pastes or liquids under standard conditions. The number of tailgroups in a surfactant has recently become an important parameter. Many surfactants have eitlier one or two hydrocarbon tailgroups, and recent advances in surfactant science include even more complex assemblies [7, 8 and 9].

Hydrocarbons are divided into two mam classes aliphatic and aromatic This classifi cation dates from the nineteenth century when organic chemistry was devoted almost entirely to the study of materials from natural sources and terms were coined that reflected a substance s origin Two sources were fats and oils and the word aliphatic was derived from the Greek word aleiphar meaning ( fat ) Aromatic hydrocarbons irre spective of their own odor were typically obtained by chemical treatment of pleasant smelling plant extracts... 

Petroleum resins are low molecular weight thermoplastic hydrocarbon resins synthesized from steam cracked petroleum distillates. These resins are differentiated from higher molecular weight polymers such as polyethylene and polypropylene, which are produced from essentially pure monomers. Petroleum resin feedstocks are composed of various reactive and nonreactive aliphatic and aromatic components. The resins are usually classified as C-5... 

Hydrocarbons, compounds of carbon and hydrogen, are stmcturally classified as aromatic and aliphatic the latter includes alkanes (paraffins), alkenes (olefins), alkynes (acetylenes), and cycloparaffins. An example of a low molecular weight paraffin is methane [74-82-8], of an olefin, ethylene [74-85-1], of a cycloparaffin, cyclopentane [287-92-3], and of an aromatic, benzene [71-43-2]. Cmde petroleum oils [8002-05-9], which span a range of molecular weights of these compounds, excluding the very reactive olefins, have been classified according to their content as paraffinic, cycloparaffinic (naphthenic), or aromatic. The hydrocarbon class of terpenes is not discussed here. Terpenes, such as turpentine [8006-64-2] are found widely distributed in plants, and consist of repeating isoprene [78-79-5] units (see Isoprene Terpenoids). 

Hydrocarbon resources can be classified as organic materials which are either mobile such as cmde oil or natural gas, or immobile materials including coal, lignite, oil shales, and tar sands. Most hydrocarbon resources occur as immobile organic materials which have a low hydrogen-to-carbon ratio. However, most hydrocarbon products in demand have a H C higher than 1.0. 

Immobile hydrocarbon sources requite refining processes involving hydrogenation. Additional hydrogen is also requited to eliminate sources of sulfur and nitrogen oxides that would be emitted to the environment. Resources can be classified as mostiy consumed, proven but stiU in the ground, and yet to be discovered. A reasonable estimate for the proven reserves for cmde oil is estimated at 140 x 10 t (1.0 x 10 bbl) (4). In 1950 the United States proven reserves were 32% of the world s reserve. In 1975 this percentage had decreased to 5%, and by 1993 it was down to 2.5%. Since 1950 the dominance of... 

Synthetic oils have been classified by ASTM into synthetic hydrocarbons, organic esters, others, and blends. Synthetic oils may contain the following compounds diaLkylben2enes, poly(a-olefins) polyisobutylene, cycloaUphatics, dibasic acid esters, polyol esters, phosphate esters, siUcate esters, polyglycols, polyphenyl ethers, siUcones, chlorofluorocarbon polymers, and perfluoroalkyl polyethers. 

Condensable hydrocarbons are removed from natural gas by cooling the gas to a low temperature and then by washing it with a cold hydrocarbon hquid to absorb the condensables. The uncondensed gas (mainly methane with a small amount of ethane) is classified as natural gas. The condensable hydrocarbons (ethane and heavier hydrocarbons) are stripped from the solvent and are separated into two streams. The heavier stream, which largely contains propane with some ethane and butane, can be Hquefied and is marketed as Hquefied petroleum gas (LPG) (qv). The heavier fractions, which consist of and heavier hydrocarbons, are added to gasoline to control volatihty (see Gasoline and other motor fuels). 

ButyUithium is available in hydrocarbon media, eg, hexane, heptane, cyclohexane, and toluene in several concentrations, eg, 15, 25, and 90 wt %. It is shipped commercially in 10-, 19-, 106-, 216-, and 454-L cylinders and 1900-L (500-gal) tanks and in bulk in 19,000-L (5,000-gal) tank tmcks and 30,300-L (8,000-gal) rail tank cars. For shipment purposes, / -butyUithium is described as a pyrophoric fuel and is classified as a flammable Hquid. As such, full precautions should be taken according to handling instmctions (100). 

The term naphthenic acid, as commonly used in the petroleum industry, refers collectively to all of the carboxyUc acids present in cmde oil. Naphthenic acids [1338-24-5] are classified as monobasic carboxyUc acids of the general formula RCOOH, where R represents the naphthene moiety consisting of cyclopentane and cyclohexane derivatives. Naphthenic acids are composed predorninandy of aLkyl-substituted cycloaUphatic carboxyUc acids, with smaller amounts of acycHc aUphatic (paraffinic or fatty) acids. Aromatic, olefinic, hydroxy, and dibasic acids are considered to be minor components. Commercial naphthenic acids also contain varying amounts of unsaponifiable hydrocarbons, phenoHc compounds, sulfur compounds, and water. The complex mixture of acids is derived from straight-mn distillates of petroleum, mosdy from kerosene and diesel fractions (see Petroleum). 

In general, when the product is a fraction from cmde oil that includes a large number of individual hydrocarbons, the fraction is classified as a refined product. Examples of refined products are gasoline, diesel fuel, heating oils, lubricants, waxes, asphalt, and coke. In contrast, when the product is limited to, perhaps, one or two specific hydrocarbons of high purity, the fraction is classified as a petrochemical product. Examples of petrochemicals are ethylene (qv), propylene (qv), benzene (qv), toluene, and xylene (see Btx processing). 

A classification by chemical type is given ia Table 1. It does not attempt to be either rigorous or complete. Clearly, some materials could appear ia more than one of these classifications, eg, polyethylene waxes [9002-88 ] can be classified ia both synthetic waxes and polyolefins, and fiuorosihcones ia sihcones and fiuoropolymers. The broad classes of release materials available are given ia the chemical class column, the principal types ia the chemical subdivision column, and one or two important selections ia the specific examples column. Many commercial products are difficult to place ia any classification scheme. Some are of proprietary composition and many are mixtures. For example, metallic soaps are often used ia combination with hydrocarbon waxes to produce finely dispersed suspensions. Many products also contain formulating aids such as solvents, emulsifiers, and biocides. 

Solvent Characteristics. Solvents are conveniendy classified as hydrocarbons or nonhydrocarbons. The latter are generally oxygenated compounds. 

Liquid-Phase Components. It is usual to classify organic Hquids by the nature of the polar or hydrophilic functional group, ie, alcohol, acid, ester, phosphate, etc. Because lowering of surface tension is a key defoamer property and since this effect is a function of the nonpolar portion of the Hquid-phase component, it is preferable to classify by the hydrophobic, nonpolar portion. This approach identifies four Hquid phase component classes hydrocarbons, polyethers, siHcones, and duorocarbons. 

Historically, measurements have classified ambient hydrocarbons in two classes methane (CH4) and all other nonmethane volatile organic compounds (NMVOCs). Analyzing hydrocarbons in the atmosphere involves a three-step process collection, separation, and quantification. Collection involves obtaining an aliquot of air, e.g., with an evacuated canister. The principal separation process is gas chromatography (GC), and the principal quantification technique is wdth a calibrated flame ionization detector (FID). Mass spectroscopy (MS) is used along with GC to identify individual hydrocarbon compounds. 

Airborne material affecting the quality of indoor air may be classified as gases or particulate matter. Gases which may be potential problems are radon, CO, NOj, and hydrocarbons. Particulate matter may come from tobacco smoke, mold spores, animal dander, plant spores, and others as shown in Table 23-1. Other factors interact to influence our perception of indoor air quality, including humidity, temperature, lighting, and sound level. 

Amorphous carbon films may be broadly classified as (i) amorphous carbon films, a-C films, deposited from carbon-containing gases with low or zero hydrogen content [72] and (ii) hydrogenated carbon films, a-C H films, formed from hydrocarbon-containing gases [73,74]. Both types of film contain different amounts of sp and sp bonded carbon. The amount of sp bonded carbon can be estimated from X-ray absorption near edge spectroscopy,... 

The last group of substituted hydrocarbons produced by adding hydroxyl radicals to the hydrocarbon backbone are the compounds made when three hydroxyl radicals are substituted these are known as glycerols. The name of the simplest of this type of compound is just glycerol. Its molecular formula is 3115(011)3. Glycerol is a colorless, thick, syrupy liquid with a sweet taste, and has a flash point of 320°F, and is used to make such diverse products as candy and explosives, plus many more. Other glycerols are made, but most of them are not classified as hazardous materials. 

Polycyclic aromatic hydrocarbons have been classified as human carcinogens because they induce cancers in experimental animals and because smoking and exposure to mixtures of chemicals containing polycyclic aromatic hydrocarbons in the workplace increase the risk of lung cancer in exposed individuals. In experimental animals, benzo(a)pyrene induces cancer in different organs depending on the route of administration.Furthermore, exposure to polycyclic aromatic hydrocarbons commonly occurs in occupations related to traffic (use of diesel engines in transportation and railways). 

Figure 15-19. Insulation on this Fire woter pump is not necessary because it is not o hydrocarbon handling vessel and is not located in a classified area or work area.

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