Hydrocarbons, also called hydrocarbons, areOrganic compoundOne of.This kind of compound is only composed of two elements, hydrocarbon. Its density is mostly smaller than that of water, and it is insoluble in water,SolubletoOrganic solvent。It containsalkane、olefin、Alkyne、Alicyclic hydrocarbonandAromatic hydrocarbon, is the matrix of many other organic compounds, which is the parent of organic compounds.
General formula of alkane: CnHtwon+2(nGreater than or equal to1) , olefin general formula: CnHtwon(n≥ 2),DieneGeneral formula: CnHtwon-2(n≥ 3), general formula of naphthenic hydrocarbon: CnHtwon(n≥ 3), alkyne general formula: CnHtwon-2(n ≥ 2), aromatic hydrocarbon has no fixed general formula, in which benzene and itshomologueThe general formula is: CnHtwon-6(n ≥ 6)[1]。
Hydrocarbons in petroleum
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Hydrocarbon is the abbreviation of hydrocarbon, which is a combination of "fire" in "carbon" and "appropriate" in "hydrogen".Hydrocarbons are divided intoSaturated hydrocarbonandUnsaturated hydrocarbon。PetroleumHydrocarbonsIt is mostly saturated hydrocarbon, but unsaturated hydrocarbon,olefinasethylene、AlkyneasacetyleneIn addition, unsaturated hydrocarbons includeAromatic hydrocarbonSuch as benzene,toluene、ethylbenzene, naphthalene, anthracene, etc., are generally only obtained during petroleum processing.There are three types of hydrocarbons in petroleum:
yescarbon atomBetweenSingle bondLinked chain hydrocarbons.Because the carbon and hydrogen components of hydrocarbonAtomic numberAs a result, petroleum contains hydrocarbon molecules that differ greatly from each other.Alkanes are named according to the number of carbon atoms in the molecule. For those with less than 10 carbon atoms, from 1 to 10, use A, B, C, D, E, H, G, Xin, NoneDecaneIf the number of carbon atoms is more than 11, use numbers.Alkanes in petroleum includeN-alkaneandIsoalkanes。The content of n-alkanes in paraffin based oil is high;Isoalkanes inasphaltThe content of cornerstone oil is high.Alkanes are also called alkane hydrocarbons.The general formula of the molecular formula of alkanes is CnHtwon+2, wherenThe number of carbon atoms in the molecule.twon+2 indicateshydrogen atomThe number of.At normal temperature and pressure, Cone-Cfour% alkanes are gaseous and exist in natural gas;Cfive-CsixteenIts alkanes are liquid and the main components of petroleum;CsixteenThe above alkanes are solid.
As the name suggests, it is a ring structure.The most common ring is composed of five carbon atoms or six carbon atoms. The former is calledCyclopentane, the latter is calledcyclohexane。The general formula of the molecular formula of naphthenic hydrocarbon is CnHtwon。Cycloalkanes are also called naphthenic hydrocarbons.
It is also called aromatic hydrocarbon.Generally, there are one or more six membered rings with special structure(benzene ring)Composition.The simplest aromatic hydrocarbon is benzenetoluene、xylene。They came fromPetroleum refining processinPlatinum reformingIt can be obtained in the production of the device.In aromatic hydrocarbonsHomologue of benzeneThe general formula of the molecular formula of is CnHtwon-6。[2]
Nomenclature
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1. Select the main chain (with more carbon atomsCarbon chainAs the main chain, there arefunctional groupTo select the chain containing functional groups as the main chain)
2. Main chain number (follow "near", "simple" and "small")
1. Alkanes are generally referred to as "some alkanes", which refers to the number of carbon atoms in alkanes.From one to ten, they are represented by A, B, C, D, E, Ji, Geng, Xin, Ren, Kui, and from ten, they are represented by Chinese characters.
For example: (1) CHfourcallmethane,CHthreeCHthreecallethane,CHthreeCHtwoCHthreecallpropane;
2. In order to distinguish isomers, they are represented by "positive", "different" and "new".
The common naming method is simple and convenient.But it can only be used for alkanes with simple structure.For alkanes with complex structureSystem nomenclature。
System nomenclature
In system nomenclature, forBranched chainAlkanealkylSubstituent derivatives.
Hydrocarbon molecule
The remaining part of a hydrocarbon molecule that loses a hydrogen atom is calledAlkyl group;The remaining part of an alkane molecule that loses one hydrogen atom is called alkyl.General formula: CnHtwon+1(n ≥ 1), usually represented by "R -".
For branched alkanesNomenclatureThe following steps can be followed:
(1) Determine the main chain and call it "certain alkane"。
Select the longest carbon chain in the molecule as the main chain, and call it "some alkane" according to the number of carbon atoms on the main chain.(Those with a carbon atom number of 1~10 are named after A, B, C, D, E, Ji, Geng, Xin, Ren, Kui.)
The carbon chain in the line of the above formula is the longest. As the parent, it contains six carbon atoms, so it is called hexane.Methyl is used as substituent.
(2) Start numbering from the end closest to the branch chain, and determine the location of the branch chain。
① After the main chain is selected, it is necessary to number the position of the main chain, that is, to determine the position of the substituent. The main chain is numbered from one end to the other. The number is represented by 1, 2, 3 ┉┉, and read into 1, 2, 3 ┉, and so on.
② Simple alkanes shall be numbered from the end closest to the branch chain, and the position and substituent nouns shall be connected by a half word line "-".When there are several numbering possibilities, the substituent should be selected to minimize its position.
Example: ① CHthree—②CHtwo— ③CH(CHthree)— ④CHtwo— ⑤CHtwo— ⑥CHthree
(3) Write the name. The same base is combined, and the different substituents are from small to upper case.
① If there are several identical substituents, combine them. The number of substituents is expressed by one, two, three, etc., written in front of the substituent;If there are several different substituents, write the name of the small substituent in the front and the large one in the back (the order of alkyl is methylethyl, propylbutyl, amylHexyl、Isoamyl、Isobutyl, isopropyl chloride), their positions must be indicated one by one, and the numbers of positions must be separated by ",".
② When the chain with the same length can be used as the main chain, select the carbon chain with the largest number of branches (or the simplest branch chain).
The principles for determining the position of the main chain are:
①Longest principle: Select the longest carbon chain as the main chain
②Minimalist principle: When there are two main chains of the same carbon atom, the simplest branch chain is selected as the main chain.
③Recent principle: The starting point is the nearest to the branch chain
④Minimum principle: When the distance between the branch chain and the two ends is the same, the sum of the values at the position of the substituent is the smallest[1]。