Homologous series of alkanes, alkenes and alkynes with. Alkenes and alkynes from organic chemistry by robert c. Naming alkanes, alkenes, and alkynes chemistry socratic. Alkanes are useful as fuels and alkenes are used to make chemicals such as plastic. Since cc bonds have sp2 hybridized c, atoms or groups directly attached to a cc bond lie in a plane and are separated by approximately 120 bond angles. Since the cc can be located in different positions in unbranched alkenes with four or more cs, they have structural isomers. Alkynes are hydrocarbons with carboncarbon triple bonds. Both are termed unsaturated because the carbons involved in the multiple bonds do not have the maximum number of bonded atoms possible four for a carbon. Though these three hydrocarbon varieties are similar, there is a difference in bonding. Introduction to alkenes and alkynes in an alkane, all covalent bonds. Quiz 70 most hydrogen atoms are not shown for clarity 1 2 cc c c c c cc cc c c c c 3 4 c c c cc c c br c c c c c c c c c 5 6 c ccc ff f c ccc cc h h 7 8.
Not to be confused with alkene, alkali, alkyne, or alkaline. Pdf prediction of the equivalent alkane carbon number eacn of. The same thing can be observed in case of alkenes in which the first member is ethene and the successive members are c 3 h 6, c 4 h. Acetylene itself is formed from the reaction of the inorganic compound calcium carbide with water.
They are made of carbon and hydrogen atoms only and contain two types of bonds, carbon hydrogen ch and carboncarbon cc single covalent bonds. In the iupac system, change the ane ending of the parent alkane name to the suffix yne. The main preparative reactions involve the elimination of groups or ions from molecules, resulting in the formation of. You must complete the tests with bromine and potassium permanganate parts c and d above before doing an unknown. Simple alkynes are named much like alkenes, except the ending is changed fromane toyne. Alkynes may have one or more triple bonds in their structure.
For example, a c5h10 compound with one double bond at the first carbon would be called 1pentene pent indicating 5 carbons and ene indicating the double bond. In the presence of certain catalysts called initiators, many. Me 2s formation of aldehydes and ketones from alkenes including complete mechanism. Oxyfunctionalization of alkanes, alkenes and alkynes by. Reaction in which the elements of water h and oh are.
Hydrogenation of alkenes and alkynes hydrocarbons that have carboncarbon double bond are called alkenes. Nomenclature of alkanes, alkenes and alkynes iupac. Its ability to oxygenate nalkanes, nalkenes, ethers, and. Cng, petrol, diesel are used as fuels for automobiles.
Alkynes are similar to alkenes in both physical and chemical properties. Reactions of alkenes and alkynes introduction to chemistry. Physical properties nonpolar and insoluble in water as are alkanes. They can be gases as, propane, they can be liquids, for example, benzene, or they can be low.
Naming and drawing alkenes for each alkene write the correct iupac name. The simple difference between alkanes, alkenes, and alkynes. Alkynes are named in the same general way that alkenes are named. Metabolism of nalkanes and nalkenes by anaerobic bacteria. Unsaturated hydrocarbons can participate in a number of different addition reactions. Alkenes, alkynes, and aromatic compounds hydrocarbons with multiple bonds. This group of compounds is a homologous series with the general molecular formula of c n h 2 n 2, where n equals any integer greater than one. Properties of alkanes alkenes and alkynes nomenclature isomers preparation of alkenes and alkynes additions to alkenes and alkynes electrophilic additions hydration hydrogenation halogenation mechanisms and stereochemistry polymerization oxidations of alkenes and alkynes dienes reactions of dienes terpenes and rubber. But the alkenes obtained from the addition of an electrophilic reagent to an alkyne have at least one electronegative atom cl, br, etc. In the study of organic chemistry, the organic compounds which are made up of carbon and hydrogen are called hydrocarbons. They called unsaturated because the c atoms in a cc double bond dont have as many hydrogens bonded to them as an alkane does. General formula is cnh2n2 two elements of unsaturation for each triple bond. There are, however, some microorganisms possessing the metabolic capacity to utilize nalkanes as both. So you can synthesize alkynes from alkenes, or you could synthesize an alkyne from a dihalide.
Alkenes have the formula c n h 2n and alkynes use the formula c n h 2n2. Reactions and synthesis of alkenes section 6 of organic chemistry notes is 14 pages in length page 61 through page 614 and covers all youll need to know on the following lecturebook topics. Addition reactions generally the reaction is exothermic because one. Difference between alkanes and alkenes compare the. Determination of the % fe in an unknown by titration. Alkenes, alkynes, and aromatic compounds hydrocarbons with multiple bonds outline. Alkanes are divided into linear nalkanes, branched alkanes, and cycloalkanes. Alkenes and alkynes organic chemistry science khan. Chemically, the alkynes are similar to the alkenes. Ch bonds in alkanes and unsaturated hydrocarbons are so highly localized that their nonsteric.
Molecules with one double bond are called monounsaturated. Alkanes with unbranched carbon chains are also known as normal alkanes or n alkanes. The carbon atoms in each exhibit a valency of four. The reaction of acetylene with bromine is a typical example. Hunter, department of chemistry, youngstown state university chemistry 1506. So lets go ahead and draw in our benzene rings, like that. Structure of alkynes the functional group of an alkyne is a carboncarbon triple bond. Reaction in which halogen is introduced into a molecule 3 hydration. Alkynes section 7 of organic chemistry notes is 12 pages in length page 71 through page 712 and covers all youll need to know on the following lecturebook topics. Draw the line bond structures for the following alkenes, cyclic alkenes, and alkynes.
Alkanes are much more stable than alkenes because of the presence of the cc double bond. The international union of pure and applied chemistry iupac names for alkynes parallel those of alkenes, except that the family ending is yne rather than ene. Organic chemistry notes naming alkynes and reactions of. Nonpolar, therefore boiling points depend on size and shape. Alkanes, alkenes, aromatic hydrocarbons and isomers related study materials. Number the chain from the end closest to the triple bond. Examples for other subcategories of hydrocarbons are alkenes, alkynes and. Unsaturated hydrocarbons, alkenes and alkynes, not only burn, but also react by addition of reagents to the double or triple bonds. The most common alkyne is ethyne, better known as acetylene. General reaction equation for addition to alkynes alkynes add hydrogen, hydrogen halides, and halogens chlorine and bromine. In case of alkenes double bond linkages are seen and in alkynes, triple bond linkages are present. The first practice problem is a summary of alkyne reactions followed by comprehensive synthesis practice problems, all the major classes of alkyne and alkene reactions are covered.
Hydrocarbons are organic compounds which only consist of carbon c and hydrogen h as their elements. Preparations of alkanes,alkenes,alkynes free download as powerpoint presentation. Molecular and structural formulas the alkynes comprise a series of carbon. Alkanes are less dense than water and swim on top of water 2. The key difference between alkanes and alkenes is their chemical structure. This method was once an important industrial process for the manufacture of acetylene. In particular, these molecules can participate in a variety of addition reactions and can be used in polymer formation. Rules underlying iupac nomenclature of alkanes, alkenes, and alkynes are discussed below.
Preparations of alkanes,alkenes,alkynes alkene chlorine. Alkanes, alkenes, aromatic hydrocarbons and isomers. Dec 08, 2014 alkanes contain a single bond, alkenes contain a double bond, and alkynes contain a triple bond. In the presence of certain catalysts called initiators, many alkenes form polymers by the addition of monomers greek. For example, alkynes undergo many of the typical addition reactions of alkenes. Alkanes, alkenes, and alkynes are made up of carbon and hydrogen.
The hydrocarbons that has carbon carbon single bond. Reactions of alkenes and alkynes o dihydroxylation of an alkene using oso 4 and water you do not need to know the whole mechanism, but you need to be able to draw the first step and explain the syn stereospecificity o ozonolysis 1. Alkenes have the general formula c n h 2n and alkynes are c n h 2n2. Apr 05, 2014 alkanes, alkenes, alkynes and cycloalkanes are hydrocarbons compounds containing only carbon and hydrogen. They are also sometimes referred to as olefins or as unsaturated compounds. The longest hydrocarbon chain is selected and is termed as parent chain in case of alkanes. Determine which class of hydrocarbons alkane, alkene, or alkyne that your unknown belongs to by reacting it with. Alkanes and alkenes are both families of hydrocarbons.
Organic chemistry university of california riverside. Alkenes and alkynes, on the other hand, are unsaturated hydrocarbons. Key difference alkanes vs alkenes alkanes and alkenes are two types of hydrocarbon families which contain carbon and hydrogen in their molecular structure. Elimination reactions from organic chemistry by robert c. Alkenes having one double bond, thus lost 2 hydrogens or alkynes a triple. Alkanes do undergo a substitution reaction with halogens, but require activation by ultraviolet light to make the reaction proceed. Carboncarbon pbond of alkenes and alkynes can be reduced to the corresponding saturated cc bond. Hydrocarbons 365 unit after studying this unit, you will be able to name hydrocarbons according to iupac system of nomenclature. So it doesnt really matter how we draw our electrons, so well go ahead and do this. Saturated compounds contain single bonds only and unsaturated compounds contain double or triple bonds. In organic chemistry, an alkane, or paraffin is an acyclic saturated hydrocarbon.
Alkenes have at least one double bond and alkynes have at least one triple bond. The preparations of alkynes are very similar to those of the alkenes. It finds widespread use in many empirical correlations to evaluate the environmental fate of pollutants as well as in the design of pharmaceuticals. Additions are the most common reactions using alkenes and alkynes addition to. Organic chemistry is the study of carbon compounds, so the study of organic chemistry is important because all living things are based on carbon compounds. The reaction uses h2 and a precious metal catalyst. Naming and drawing alkanes for each alkane write the correct iupac name. Chapter 9 2 introduction alkynes contain a triple bond. Organic reactions summary alkenes, alkynes and variations. Section 6 reactions and synthesis of alkenes 61 addition of halogens x2 stereochemistry antiaddition observed bromonium ion intermediate. The successive members vary from each other by a ch 2 unit.
The structure of alkynes a triple bond is composed of a. Alkanes are a group of acyclic, saturated hydrocarbons. Section 7 alkynes 71 definition, bond length, and bde of alkynes 71 alkyne nomenclature yne ending alkenynes compounds having both double bonds and triple bonds. Unbranched alkenes are analogous to unbranched alkanes. Alkenes and alkynes organic chemistry science khan academy. Pdf the equivalent alkane carbon numbers eacns of 16 aprotic polar. The experimental evaluation of 1octanolwater partition. Cc bond formation synthesis of alkenes and alkynes dehydrohalogenation 5. Lecture note on alkenes and alkynes this is a comprehensive lecture note on alkenes and alkynes alkenes contain less hydrogen, carbon for carbon, than the alkanes. Methods of preparation of alkynes by dehydrohalogenation of. Addition of h2 across the pbond of an alkene to give an alkane. Hunters class section 2 notes page 129 20002002, dr. Naming alkanes, alkenes, alkynes, and types of isomers.
In addition, the type of bonding in organic compounds is almost always covalent. Alkanes, alkenes and alkynes are all hydrocarbons with different structures and thus different physical and chemical properties. Properties of alkenes and alkynes chemical properties undergo combustion as do alkanes. Compound composed of only carbon and hydrogen saturated hydrocarbons. Alkanes alkanes are the simplest class of organic compounds. Reactions of alkenes and alkynes o open computing facility. As an example, consider the reaction of methane with chlorine gas. Alkenes and alkynes are generally more reactive than alkanes due to the electron density available in their pi bonds. Choose the longest continuous chain that contains both atoms of the triple bond and number the chain to give the triple bond the lower number.
These include the preparation dialkyl halides and their use in preparation of alkynes by elimination reactions, hydrohalogenation, hydration, hydroboration. Reactions of alkynes in organic synthesis with practice problems. No reaction takes place between the two gases at room. Naming alkanes, alkenes, alkynes, and types of isomers denovo tutor. To account for this difference, the carbon atoms are joined by a double bond. Hydrocarbons are compounds made up of carbon and hydrogen and these hydorcarbons form important fuels like petroleum,diesel etc. Rules for writting structural formula of alkanes, alkenes and alkynes definition alkanes have cc and ch single bond, each c is sp 3 hybridized therefore it forms sigma bonds. For 3dimensional structure fisher projection formula can be used. Carbon is unique in that it can form up to four bonds in a compound, so they can easily bond with other carbon atoms, forming long chains or rings.