烷和烯烃的性质

1、烷和烯烃的性质（ The properties of alkane and olefin）Methane and alkane1, carbon atoms of organic molecules and carbon atoms by C - C are connected into carbon chain, all remaining valence bond is saturated by H chain formed by organic compounds, called saturated hydrocarbon chain, or alkane. The mostrepres

2、entative of alkanes is methane, also known as biogas, gas, gas, etc.Methane is a colorless, odorless gas, small density than air,insolublein water,methane, CH4C atoms in molecules with sp3hybridizedfor m covalentbond, bond Angle is 109.5 °, form thespace structure are all size.The chemical prop

3、erties of methane are mainly reflected in combustion and substitution reactions:The combustion of methane:Phenomenon: the flame is bright and light blue, and 1molCH4 burns out 890kJ heat. The products of CO2 and H2O are free of pollution. Therefore, natural gas, which is mainly composed of methane,

4、is a kind of clean energy.Methane can be burned, but cannot be oxidized by acidic KMnO4 solutions;The substitution of methane:Mechanism of this reaction is one of the methane moleculeshydrogen atoms are replaced by chlorine gas molecules in a chlorine atom, in turn, generate a methyl chloride, methy

5、lene chloride, chloroform, four chloride methane, hydrogen and chlorine gas molecules replace down in another chlorine atoms combine to generate hydrogen chloride, reaction products a total of five.Methane can be decomposed in high temperature: CH4, C + 2H22, the structure and properties of alkanes

6、and methane are similar, under normal circumstances, the melt boiling point increase as the number of C atoms of alkane and increases,density increases gradually, a C atomic number at the same time, with the increasing of the branched chain, melt boiling pointdecreases of molecular alkane carbon num

7、ber less than or equal to 4, a gas under atmospheric pressure; Alkanes are not soluble in water, but are soluble in organic solvents.Due to the molecularstructureof alkanes and methane moleculesare similar, so they have similar properties and methane: a, alkanes is stable, can't be acidic KMnO4

8、oxidation, does not react with strong acid, strong alkali; B. Easy to burn; C. In the light condition, it is substituted for the halogen, suchas Cl2 and Br2. D: decompositionreactionat high temperature.that1, at high temperature, paraffin decomposition reaction, notnecessarilythe same, but the produ

9、ctcan generate olefinsandnaphthenes short chains of gaseous hydrocarbon, also cangenerate C and H2, such as: oilthermalcrackingand catalyticcracking, is to high boiling hydrocarbon fracture as a short chain of low boiling point hydrocarbon process;2, the substitutionreactionof organicmatteris to poi

10、ntto:organicmolecules of the atoms replaced by other atoms or groupsof atoms or radicals reactions, not necessarily confined toalkanes,benzene and itshomologue, halogenatedhydrocarbons,alcoholsand other hydrocarbon derivatives,etc allcan happensubstitution reaction, substitution reaction occurs, org

11、anic matter to generate a small molecules, such as: HX, H2O, etc;3. When the alkanes are substituted for the reaction, the products are many and complex. Therefore, it is generally not replaced by the reaction to make the halogenated hydrocarbon.4. The disubstituted products of methane have no isome

12、rs, indicating that the molecular structure of methane is apositivefour-sidedshape ratherthan a flatsquare structure.1. The fact that the methane molecular space structure is a regular tetrahedron is:A. The bonds of the four hydrogen bonds of methane are equalB. The bond of the four hydrogen bonds o

13、f methaneC.There is only one chlorination of methaneD. methane has only one chlorinated agentThis is a test of methane space structure. The space configuration of methane may have two kinds of plane squares and a tetrahedral structure. Whether it is A, B, or C, A, B,and C cannot prove whether the sp

14、ace configuration of methane is one or two.Answer: DExample 2. Replace the 1molCH4and Cl2 with the reaction. After the reaction is completed, the amount of material measured inthe four substituents is equal, and the Cl2 is consumed as follows:A.0.5 moles of b. 2 moles c. 2.5 molesAnalysis: the subst

15、itution of CH4 and Cl2 for the productionof four kinds of substances, namely: CH3Cl, CH2Cl2, CHCl3, CCl4 and the same amount, all of which are 0.25 mol; And since the alkanes are substituted for the X2, each of the X atoms is substituted for an HX, consuming one X2, and the amount of material consum

16、ed is:0.25 moles of 1 plus 0.25 moles of 2 plus 0.25 moles of 3 plus0.25 moles of x is 2.5 molesAnswer: CExample 3. Write down the structure of a chlorinated substance in an alkane that has less than 10 carbon atoms.Analysis: there is only one chlorinated substitute, indicating that all H atoms in t

17、his organic matter are equivalent, thatis, in a symmetric position. Due to the same C atoms are connected H atoms are equivalent, so CH4, CH3 - a chlorinated CH3 is only a kind of structure, also, the same C atoms are connected - also equivalent CH3, since CH3 equivalent, CH3 H atoms are equivalent,

18、 so:There is only one kind of halogenated hydrocarbon structureCH4, CH3 - CH3,A total of four kinds of(2) ethylene and olefins1. Ethyleneis a colorless,slightlyodorous gas, difficulttodissolvein water, with a densityof 1.25 g · l -1 under standardconditionsEthylene molecule of carbon in sp2 hyb

19、ridization between carbon atoms form a covalent bond, one of the key rupture easily, thuscan happen bonus or addition polymerization, can make the bromine water fade and KMnO4 solution (acid).As a result of the existence of C = C double bond, the nature of the ethylene more lively, can be acid oxida

20、tion by KMnO4 solution, can also with materials such as bromine water addition reaction, addition polymerization under certain conditions can also happen to generate organic polymer compounds.(1) oxidation reaction: ethylene can not only burn, but also make acidic KMnO4 solution fade.(2) addition re

21、action: ethylene can be combined with X2, H2O, HX, HCN and other substances(3) reaction:2. Olefin: a type of chain hydrocarbon containing double bonds of carbon is called an alkene. The general formula:As the number of carbon atoms increases,the meltingpointandboiling point of olefin are generally i

22、ncreased, and the gasphase changes from the gas phase to the liquidstate,where thenumber of C atoms is less than or equal to 4.Exist C = C in the olefin structure, its nature and ethyleneare of a similar nature can be acid oxidation by KMnO4solution, can also with X2, H2O, HX, HCN substances such as

23、 addition reaction, can happen addition polymerization under certain conditions, to generate high molecular compound.Let's take ch3-ch = CH2as an example to illustrate properties of olefins:the chemical3. Laboratory preparation of ethylene:Ethylene and other alkenes can be obtained by pyrolysis

24、of petroleum.that1, symmetric productolefinadditionreactionoccurs only one,and the asymmetry of olefins in addition reaction with polarmolecules,under normal circumstances,the positivepart of theadd on more C H atoms (commonly known as "H and H more"), lessnegatively charged parts put in H

25、 C atom, at the same timegenerate small amounts of by-products (contrary to theprinciple of addition);2. The preparation of a halogenated hydrocarbon is usually obtained by the reaction of olefins and HX.3. Laboratory preparation of ethylene:(1) the experimental device is as follows:(2) the effect o

26、f concentrated H2SO4 catalyst and dewatering agent, the effect of zeolite or scrap porcelain is to prevent the reaction mixture from being heated.(3) strong H2SO4 ismixed withethanolin 3:1. When mixing,itshould be added ethanol and concentrated sulfuric acid. Thereason of excessiveconcentrationof H2

27、SO4is thatthe reactionis directed to the positive reaction direction.(4) to quicklyrose to a temperatureby- products ether at 140.of 170 , prevent generate(5) it may be mixed with CO2, SO2 and other impurities gases in ethylene production.(6) experiments to verify the production of ethylene, mustfir

28、stgenerated by alkalisolutionto remove the acid gas suchas SO2, CO2, and then pass intothe bromine water or acid KMnO4solution, otherwise, the SO2 may interfere with the experimental results.4. When the olefin occurs, it only has to do with C = C, and has nothing to do with single bonds. The formula

29、 for theaddition of the product is: "double - bond change single bond, the composition is not changed, both sides extend the hand, linking each other into a chain."5. Olefins containing the same number of carbon atoms areisomers with naphthene. Alkene C = C unsaturated C atom if the atom o

30、r group of atoms is different, then there is cis trans isomerism, such as:1. After the addition of a single olefin and H2, the structure of the olefins may be:A. 1 b. 2 kinds c. 3 kinds d. 4 speciesAnalytic: olefins occurred after the addition reaction: C = C- CH - CH -, according to the set: obtain

31、ed by olefin addition reaction, that is only on the adjacent two carbon atoms are H atom, just may be formed from olefin addition, and the same carbon atom of the H and CH3 are equivalent, so the corresponding olefin can only have threeAnswer: CCase 2. If a hydrocarbon molecules contain a double bon

32、d, three key or ring, its carbon atoms combine hydrogen atom number isless than the same carbon atom number corresponding alkane containing hydrogen, also has certain not saturation (expressed in , also known as lack of hydrogen index), the following table lists several hydrocarbon saturation:Organi

33、c matterCH2 = CH2CH CH1214Accordingly, the following statements are incorrect:A. 1 mol = 3 unsaturated hydrocarbon chain coupled with 6 molh saturatedB. equal to 6C. CH3CH2CH = CH2 and cyclobutane not saturationD. C4H8 is not saturated with C3H6 and C2H4According to the information,Organic matter Cn

34、Hm not saturation compared with the organicmatter and paraffinCnH2n+ 2, the relationshipbetween the lackof the number of H atoms as: = (2 n + 2) - m / 2, is inA 1 mol = 3, should be combined with 6 molh reach saturation;B = 7, not correct;C both = 1, is not the samesaturation;The unsaturation of thr

35、ee substances in D is also incorrect.So the answer is BDAnswer: the BDExample 3. Xavier confirmed that light can induce the following changes: the fact that the night vision function and can be used to explain human eyes chlorophyll in photosynthesis extremely high utilization rate of communication,

36、 the following statement is wrong:A. X and Y are isomersAll the atoms in X and Y might be on one planeC. The above changes are a physical processD. X and Y could have a plus reactionAnalytic: according to the double bond and the bondingcharacteristic of benzene ring and the space configuration ofthe

37、 two - plane structure,clearallthe atoms in molecules maybe coplanar, because there are a double bond in the molecular structure, so the addition polymerization may occur; At thesame time, the molecular formula of the two is the same, except that the positions of the atoms on the double bond carbon

38、atoms are different, so they belong to cis trans isomerism.Answer: C4. Some hydrocarbon A, the relative molecular weight of 140, of which the mass fraction of carbon is 0.857. There are twocarbons in A molecule that are not directly linked to hydrogen. A is oxidized to G only under certain condition

39、s. G can make purple litmus test liquid red. Known:Try to write: (1) the molecular formula of A.(2) the structure of compound A and G is simple: A G.(3) there may be some isomers (including G) of the same kind of G.Analytic:accordingto the organicmatterin the mass fractionof carbon, hydrogen, we can

40、 get the most short form of theorganic matter (empirical formula) for CH2, combined with therelative molecular mass of a material of the formulas for thematerial are available C10H20; By A molecule has two carbonatoms are not directly connected with hydrogen, and undercertain conditions can oxidize

41、A G, A substance that A and Gcontainscarbon atoms have the same number, can get A and G thestructure of the short form for:The molecular formula of the same kind of G is C5H10O2,c4h9-cooh. Since - COOH can only be in the last place, so theisomer of C4H9is C5H10O2,which is the isomer of acid,and ther

42、eare 4 kindsof isomers of C4H9, so thereare 4 kinds of isomersof C5H10O2.Answer: (1) C10H20;(2)(3) 4 species(3) homologues and isomers:Homologues: similar structures, molecular components of one or several "CH2" groups of compounds known as homologues. The molecular formula of the alkane h

43、omologue is CnH2n + 2, while the general formula of single alkene is CnH2n.Isomers: the samemolecularand differentstructuresof organicmatter are calledisomers, and the isomers of isomers are calledisomers. There are many different isomers of organic matter, mainly including: "carbon frame heter

44、ogeneity", "positional isomerization" and "category isomerization",Sometimes C is equal to C and the isomer of the chiral carbon atom.The general designation of alkanes can be named according tothe number of carbon atoms in the molecule. Number of carbon atoms within 10 with

45、 a, b, c, d, e, f, g, essien, nonyl, decyl, in more than 10 is numerically, such as: methane CH4, pentane C5H12, 17 alkanes C17H36, etc.System nomenclature of alkanes: the systematic nomenclature of organic matter is mainly reflected by the nameof the structure,knowing the structure to get the name.

46、 The specific steps are as follows:You choose the main chain, you call it an alkane; Number bits, set chain; Substituting the base, writing in front, marking position, short line;Different bases, simple to complex, same basis, combined.The systematic nomenclature for the hydrocarbon and hydrocarbon

47、derivatives containing the monolinis:The longest chain, which contains the functional groups, is chosen as the main chain, such as "certain ene" and "some acetylene".From the nearestend of the functionalgroup to the carbon atomin the main chain.(3) with the Arabic numerals indica

48、te the location offunctional groups (if the double bond or 3 key, simply indicate the number of carbon atom number smaller, if aldehyde or carboxylic acid, the functional group's position must be 1)The rest of the names are similar to the alkanes.that1, the homologue refers to a structure simila

49、r to that of molecules on a difference of one or several "CH2 groups of compounds, as a result, homologue formula must be different,but the same general formula, similar structure, with the same functional;2. The molecular formula of isomers is the same, but the structure is different from the

50、properties. The isomers of similar substances are similar in nature, and the differenttypes of isomers differ greatly in their isomers. The more the branched chain in the isomer, the lower the melting point ofthe substance; And the more carbon atoms there are, the more isomers;3. Whenwriting the iso

51、mers, we should follow the principle of "orderliness", "equivalence", "complementarity" and "agreement two"."Orderliness" means starting from a certain form, proceeding in sequence, generally looking at the species first. Carbon chain; Three writing

52、position (the position of the functional group and the carbon chain); And then you have the hydrogen."Equivalence" is to prevent the same kind of substance frombeing written into two isomers. In this case, the hydrogen ofspace symmetry is equivalent: the hydrogen atom of the samecarbon ato

53、m is equivalent;The equivalentof the hydrogen atomon the same carbon atom. A hydrogen atom in a mirror-symmetric position is equivalent (equivalent to a plane mirror image).4. When the system of organic matter is named, the Chinese character and the number are separated by "-", and the num

54、ber and number are separated by ", "and the small" - "has always been odd.1. If the same series of organics is defined as a series of structural formulae, it conforms to (n = 0, 1, 2, 3.). Ofcompounds. In the formula, A and B are either groups (orhydrogen), and the organic group of Wis 2, which is also called the series of the series. The properties of the same series ofcompounds tend to change regularly. Of the following four compounds, it is not called the same ser