A HYDROCARBONS

Aromatic Compounds—The carbo-cyclic compounds which in number far exceed those of the aliphatic series were originally called aromatic compounds because many of them possess aromatic properties, e.g.j oil of wintergreen, oil of bitter almonds, etc. They were included with the paraffin compounds in the various groups of alcohols, aldehydes, acids, etc. Later it was found that they differed from the aliphatic compounds and finally it was shown that the hydrocarbon benzene is related to the aromatic compounds just as methane is to the aliphatic compounds, i.e,j as the mother substance. 

Benzene Series.—This gave rise to the use of the names benzene series and benzene compounds in place of the name aromatic compounds. As many of the compounds since discovered and belonging to this series are not aromatic the former names are better as all of them are related to benzene. Strictly speaking, however, the benzene series proper does not include all of the carbo-cyclic compounds related to benzene and which are included in the terms iso-cyclic or aromatic as distinct from aliphaticy e.g., naphthalene, etc. Generally speaking, however, the names are used synonymously. 

Benzene.—What then is benzene, the mother substance of this large division of organic compounds which as we shall find are unsurpassed in their application to the industries and to daily life When coal gas is made by the destructive distillation of coal the products in the first place are. probably water, methane and ammonia. These being subjected to considerable heat result in the formation of numerous more complicated compounds. The gaseous products, consisting of methane, hydrogen, etc., constitute crude illuminating gas. The solid 

Coal Tar.—This coal tar is the crude source of many compounds of the benzene series. On redistillation of the coal tar numerous fractional distillates are obtained from which different compound are isolated, (p. 497). 

Light Oil. —The first distillate which comes over below 170° is known as light oil, because it floats on water. Most of the benzene itself is obtained by further fractionation of this light oil. 

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TMED, (CH3)2NCH2CH2N(CH3)2. B.p. 122 C a hygroscopic base which forms a hydrocarbon-soluble stable chelate with lithium ions and promotes enhanced reactivity of compounds of lithium, e.g. LiAlH4, UC4H9, due to enhanced kinetic basicity of the chelate. Used in polymerization catalysts, tetramethyl lead, TML 5 lead tetramethyl. 

One has seen that the number of individual components in a hydrocarbon cut increases rapidly with its boiling point. It is thereby out of the question to resolve such a cut to its individual components instead of the analysis by family given by mass spectrometry, one may prefer a distribution by type of carbon. This can be done by infrared absorption spectrometry which also has other applications in the petroleum industry. Another distribution is possible which describes a cut in tei ns of a set of structural patterns using nuclear magnetic resonance of hydrogen (or carbon) this can thus describe the average molecule in the fraction under study. 

The standard specific gravity is the ratio of the density of a hydrocarbon at 15.55°C (60°F) to that of water at the same temperature. It differs from the specific gravity d] which is the ratio of the density of a hydrocarbon at 15°C to that of water at 4°C. 

Figure 4.7 gives liquid and vapor phase envelopes for a hydrocarbon mixture. 

The flammability limits of a hydrocarbon depend on its chemical nature and its molecular weight. Table 4.14 gives values for some common hydrocarbons. 

Equilibrium between a Hydrocarbon Liquid and a Partially Miscible Liquid... 

Volatility is one of the most important properties of a hydrocarbon solvent. Volatility has a direct relation to the time it takes to evaporate the solvent and, therefore, to the drying time for the dissolved product. The desired value of volatility varies greatly with the nature of the dissolved product and its application temperature. Therefore, whether it be an ink that needs to dry at ambient temperature, sometimes very fast, or whether it be an extraction solvent, the volatility needs are not the same. 

Petroleum coke is in reality a hydrocarbon whose C/H ratio is very high it is usually higher than 20 and can attain 1000 after calcination. It is not, therefore, elementary carbon. 

The viscosity of a hydrocarbon mixture, as with all liquids, decreases when the temperature increases. The way in which lubricant viscosities vary with temperature is quite complex and, in fact, charts proposed by ASTM D 341 or by Groff (1961) (Figure 6.1) are used that provide a method to find the viscosity index for any lubricant system. Remember that a high viscosity index corresponds to small variation of viscosity between the low and high... 

The crankcase of a gasoline or diesel engine is in reality a hydrocarbon oxidation reactor oil is submitted to strong agitation in the presence of air at high temperature (120°C) furthermore, metals such as copper and iron, excellent catalysts for oxidation, are present in the surroundings. 

Aniline point NF M 07-021 ISO 2977 ASTMD611 Phase separation temperature of a hydrocarbon/ aniline mixture... 

Introduction and Commercial Application This section will firstly examine the conditions necessary for the existence of a hydrocarbon accumulation. Secondly, we will see which techniques are employed by the industry to locate oil and gas deposits. 

Several conditions need to be satisfied for the existence of a hydrocarbon accumulation, as indicated in Figure 2.1. The first of these is an area in which a suitable sequence of rocks has accumulated over geologic time, the sedimentary basin. Within that sequence there needs to be a high content of organic matter, the source rock. Through elevated temperatures and pressures these rocks must have reached maturation, the condition at which hydrocarbons are expelled from the source rock. 

Now using a hydrocarbon component, say ethane, as an example, let us consider the other parameter, volume, using a plot of pressure versus specific volume (i.e. volume per unit mass of the component, the inverse of the density). The process to be described could be performed physically by placing the liquid sample into a closed cell (PVT cell), and then reducing the pressure of the sample by withdrawing the piston of the cell and increasing the volume contained by the sample. 

In a normal pressure regime the pressure in a hydrocarbon accumulation is determined by the pressure gradient of the overlying water (dP / dD), which ranges from 0.435 psi/ ft (10 kPa/m) for fresh water to around 0.5 psi/ft (11.5 kPa/m) for salt saturated brine. At any depth (D), the water pressure (PJ can be determined from the following equation, assuming that the pressure at the surface datum is 14.7 psia (1 bara) ... 

Structural maps display the top (and sometimes the base) of the reservoir surface below the datum level. The depth values are always true vertical sub sea. One could say that the contours of structure maps provide a picture of the subsurface topography. They display the shape and extent of a hydrocarbon accumulation and indicate the dip and strike of the structure. The dip is defined as the angle of a plane with the horizontal, and Is perpendicular to the strike, which runs along the plane. 

The estimated probabilities of each of these events occurring are multiplied together to estimate the POS, since they must a//occur simultaneously if a hydrocarbon accumulation is to be formed. If the POS is estimated at say 30%, then the probability of failure must be 70%, and the expectation curve for an exploration prospect may look as shown in figure 6.9. 

Appraisal activity, if performed, is the step in the field life cycle between the discovery of a hydrocarbon accumulation and its development. The role of appraisal is to provide cost-effective information with which the subsequent decision can be made. Cost effective means that the value of the decision with the appraisal information is greater than the value of the decision without the information. If the appraisal activity does not add more value than its cost, then it is not worth doing. This can be represented by a simple flow diagram, in which the cost of appraisal is A, the profit (net present value) of the development with the appraisal information is (D2-A), and the profit of the development without the appraisal information is D1. 

IHP) (the Helmholtz condenser formula is used in connection with it), located at the surface of the layer of Stem adsorbed ions, and an outer Helmholtz plane (OHP), located on the plane of centers of the next layer of ions marking the beginning of the diffuse layer. These planes, marked IHP and OHP in Fig. V-3 are merely planes of average electrical property the actual local potentials, if they could be measured, must vary wildly between locations where there is an adsorbed ion and places where only water resides on the surface. For liquid surfaces, discussed in Section V-7C, the interface will not be smooth due to thermal waves (Section IV-3). Sweeney and co-workers applied gradient theory (see Chapter III) to model the electric double layer and interfacial tension of a hydrocarbon-aqueous electrolyte interface [27]. 

Chlorine substitutes the hydrogen of methane giving successively the chlorides CH3CI, CH2CI2, CHCI3 and CCI4. It is to be noted that if a hydrocarbon is unsaturated, chlorine atoms will first add to the double or triple bond after which substitution may occur. 

Drying of crystals. Whenever possible crystals should be dried in a smdl vacuum desiccator containing a suitable desiccant. The latter depends upon the nature of the solvent used c/. p. 19). However for most purposes anhydrous calcium chloride is satisfactory. If a hydrocarbon has been used in the recrystallisation, a few thin fresh shavings of paraffin wax are efficacious. 

Alkyl and aryl iodides usually react with magnesium more rapidly than the corresponding bromides, and the bromides very much more rapidly than the chlorides. Aryl (as distinct from alkyl) chlorides have usually only a slow reaction with magnesium and are therefore very rarely used. With alkyl and aryl iodides in particular, however, a side reaction often occurs with the formation of a hydrocarbon and magnesium iodide ... 

Friedel and Crafts reaction. alkyl halide condenses with an aromatic hydrocarbon in the presence of anhydrous aluminium chloride to yield, in the first instance, a hydrocarbon in accordance with the following scheme —... 

Upon warming with 10-20 per cent, sodium or potassium hydroxide solution, no ammonia is evolved (distinction from primary amides). The base, however, is usually liberated upon fusion with soda lime (see experimental details in Section IV,175) and at the same time the acyl group yields a hydrocarbon. Thus benz-p-toluidide affords p-tolu-idine and benzene. 

Electrolysis, under similar conditions, of a mixture of two carboxylic acids RCOOH and R COOH leads, in addition to normal coupling products R—R and R —R, to cross coupling R—R. If a mixture of a saturated carboxylic acid and a half ester of an ato-dicarboxylic acid is electrolysed, there are three main products, viz., a hydrocarbon (I), a mono-ester (II), and a di-ester (HI) and these are readily separable by distillation. Some unsaturated ester (IV) is often present in small quantity. 

Cerium is a component of misch metal, which is extensively used in the manufacture of pyrophoric alloys for cigarette lighters. While cerium is not radioactive, the impure commercial grade may contain traces of thorium, which is radioactive. The oxide is an important constituent of incandescent gas mantles and is emerging as a hydrocarbon catalyst in self cleaning ovens. In this application it can be incorporated into oven walls to prevent the collection of cooking residues. 

The facilities for experimental work were poor, with inadequate wet laboratory space. In our discussions, I mentioned to Kaprielian my interest in significantly extending my previous work into the area of hydrocarbon chemistry. I felt that by establishing a strong program of basic research and graduate education in hydrocarbon chemistry, USC could become a leader in this important field. Because the memory of the first Arab oil embargo was still fresh, this struck a chord with Kaprielian, who felt that he could sell my research interest to the trustees and establish a Hydrocarbon Research Institute at USC that could accommodate me, as well as other chemistry faculty members whose interests could fit into its framework. 

The Lokers had no background or business interest in ehemistry. It was Carl Franklin who told them abont USC s effort to establish a hydrocarbon research institute, and he must have also told them some-... 

It was the study of hypercarbon-containing nonclassical carboca-tions that allowed us to firmly establish carbon s ability in a hydrocarbon system to bind simultneously with five (or six or even seven) atoms or groups. It should be emphasized that carbocations represent... 

The most important point in analysing the synthesis of a hydrocarbon is where to put the carbonyl group, and this can depend on features other than common atoms. What strategies might you use in the synthesis of TM 377 ... 

Solubility in Water A familiar physical property of alkanes is contained m the adage oil and water don t mix Alkanes—indeed all hydrocarbons—are virtually insoluble m water In order for a hydrocarbon to dissolve m water the framework of hydrogen bonds between water molecules would become more ordered m the region around each mole cule of the dissolved hydrocarbon This increase m order which corresponds to a decrease m entropy signals a process that can be favorable only if it is reasonably... 

East Indian sandalwood oil contains a hydrocarbon given the name santene (C9H14) Ozona tion of santene followed by hydrolysis gives compound A What is the structure of santene" ... 

The conjugate base of a hydrocarbon is called a carbanion It is an anion in which the negative charge is borne by carbon Because it is derived from a very weak acid a car banion such as CH3 is an exceptionally strong base... 

Try making a model of a hydrocarbon that contains three carbons only one of which is sp hybridized What is its molecular formula Is it an alkyne" What must be the hybridization state of the other two carbons (You will learn more about compounds of this type in Chapter 10 )... 

Although allylic brommations and chlormations offer a method for attaching a reactive functional group to a hydrocarbon framework we need to be aware of two important limitations For allylic halogenation to be effective m a particular synthesis... 

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