Done by Lecturer: Amal Abu- Mostafa

 Refinery and tank storage facilities, like this one in Texas, are needed to change the hydrocarbons of crude oil to many different petroleum products. The classes and properties of hydrocarbons form one topic of study in organic chemistry

 Organic chemistry is the chemistry of compounds containing carbon.  The Bonding of Carbon:  Carbon is in Group IVA (4A) of the periodic table.  It has four valence electrons.  To fill its octet, it requires four additional electrons, which can be obtained through the formation of four covalent bonds.

 Carbon forms single, double, and triple bonds to achieve a filled octet.  Therefore, the possible bonding combinations for carbon are as follows:

 unique feature of carbon is its ability to form strong covalent bonds to each other while at the same time bonding strongly to atoms of other nonmetals, to form chains and rings of various lengths.  Carbon is the only element capable of forming stable extend chains, for example: CH 3 - (CH 2 ) n - CH 3

 The simplest organic compounds are: hydrocarbons, compounds containing only carbon and hydrogen.  All other organic compounds—for example, those containing O, N, and the halogen atoms—are classified as being derived from hydrocarbons.

 1. Saturated hydrocarbons are hydrocarbons that contain only single bonds between the carbon atoms. Saturated hydrocarbon molecules can be cyclic or acyclic.  2. Unsaturated hydrocarbons are hydrocarbons that contain double or triple bonds between carbon atoms.  3. Aromatic hydrocarbons are hydrocarbons that contain benzene rings or similar features.

 The alkanes are saturated hydrocarbons.  The cycloalkanes are cyclic saturated hydrocarbons.  The simplest hydrocarbon, an alkane called methane, consists of one carbon atom to which four hydrogen atoms are bonded in a tetrahedral arrangement.

 The alkanes, also called paraffins, (have the general formula C n H 2n+2. )  For n=1, methane, the formula is CH 4 ; for n=2, C 2 H 6 ; for n=3, C 3 H 8 ; and so on.

 Those are called straight-chain or normal alkanes. The structural formulas for the first four straight chain alkanes are shown.  The alkanes occur in what is called a homologous series, which is a series of compounds in which one compound differs from a preceding one by a fixed group of atoms CH 2.

 In addition to the straight-chain alkanes, branched- chain alkanes are possible.  For example, isobutane (or 2-methylpropane) has the structure  Butane and isobutane are constitutional (or structural) isomers, compounds with the same molecular formula (C 4 H 10 ) but different structural formulas.

 Isomers of pentane  Note that each isomer is a different compound with a different boiling point.

 The general formula for cycloalkanes is C n H 2n  This Figure gives the names and structural formulas for the first four members of the cycloalkane series.  In the condensed structural formulas, a carbon atom and its attached hydrogen atoms are assumed to be at each corner.

 The IUPAC rules for naming organic compounds follow a regular pattern.  The names of all saturated hydrocarbons, for example, end in – ane.  For each family there is a rule for picking out and naming the parent chain or parent ring within a specific molecule.  [The International Union of Pure and Applied Chemistry (IUPAC)]

 1- Find the longest continuous chain of carbon atoms and use the name of this chain as the base name for compound.  2- Number the carbon atom in the longest chain beginning with end of the chain that is nearest to the substituent.  Any branch that consists only of C and H and has only single bonds is called an alkyl group and the name of all alkyl groups end in - yl  3- Name and give location of each substituent group  4- when 2 or more substituent are present, list them in alphabetical order

 3- Chloro- 4- methyl hexane  2,3-dimethyl butane  3- ethyl- 2- methyl pentane 

 2,2-dimethyl butane 2-methyl pentane  3-methyl hexane

 Alkanes are relatively unreactive at room temperature.  They don’t react at room temperature with acids or bases or even oxidizing and reducing agents, because of the strength of the bonds C-C and C-H.  Alkanes burn in air to give water and oxides of carbon (CO 2 and CO), H 2 O  2C 2 H 6 + 7O 2 4 CO 2 + 6H 2 O

 Another type of alkane reaction is cracking  When heated at high temperatures in the absence of air, alkanes “ crack”, meaning that they break up into smaller molecules.  For example: ethane is cracked to give ethene in the presence of a catalyst  C 2 H 6 high temp. C 2 H 4 + H 2  Also, Alkane undergo substitution reaction  C 2 H 6 + Cl 2 CH 3 CH 2 Cl + HCl  But, this type of reaction is difficult to control, and yield different compounds such as C 2 H 4 Cl 2, C 2 H 3 Cl 3

 Unsaturated hydrocarbons are hydrocarbons that consist one or more multiple bond (double or triple bond). 1)Alkenes: unsaturated hydrocarbons that contain double bond.  Open chain alkenes have the General Formula : C n H 2n as: C 3 H 6, C 4 H 8, C 6 H 12  The simplest alkenes is ethene or ethylene CH 2 =CH 2  Next one is propene (propylene) CH 3 -CH=CH 2  Example: CH 3 -CH 2 -CH=CH 2 [1-butene]  CH 3 -CH=CH-CH 3 [2-butene].

 Unsaturated hydrocarbon that contain triple bond  C C  General formula for alkynes (when open chain): C n H 2 n- 2  e.g. : C 2 H 2, C 3 H 4, C 4 H 6  Simplest alkyne is ethyne or (acetylene)  Examples:  1- propyne 1- butyne

 A double bond has more electron density than a single bond.  Both alkenes and alkynes undergo addition reactions.  (e.g. addition of H 2 to alkene yeild alkane)  CH 2 =CH 2 + H 2 Pt or Ni CH 3 -CH 3  Similar reaction occur with alkyne but the product is alkene then followed by alkane.  + H 2 Pt H 2 C=CH 2 Pt CH 3 -CH 3 ethyne ethene H 2 ethane

 1- addition of HBr  H 2 C=CH 2 + HBr CH 3 -CH 2 Br  2- Addition of H 2 O H 2 C=CH 2 + H 2 O acid catalyst CH 3 -CH 2 OH  3- Addition of Cl 2 : + Cl 2 Cl 2

 Aromatic hydrocarbons usually contain benzene rings: six-membered rings of carbon atoms with alternating carbon–carbon single and carbon–carbon double bonds.  The electronic structure of benzene can be represented by resonance formulas.  Benzene :

 Simple benzene-containing hydrocarbons that have one group substituted on a benzene ring, for example:  When two groups are on the benzene ring, three isomers are possible. The isomers may be distinguished by using the prefixes ortho- (o-), meta- (m-), and para- (p-).  For example:

 It is sometimes preferable to name a compound containing a benzene ring by regarding the ring as a group in the same manner as alkyl groups, ( phenyl group, C 6 H 5 —)  For example :Diphenylmethane

 A functional group is a reactive portion (part) of a molecule that undergoes predictable reactions.  Organic compounds containing oxygen:  Examples are alcohols, ethers, aldehydes, ketones, carboxylic acids, and esters.  1) Alcohols:  They are molecules that contain OH group attached to a carbon atom which in turn attached to 3 other groups by single bonds.

 Alcohols are named by IUPAC rules similar to those for the hydrocarbons, except that the stem name is determined from the longest chain containing the carbon atom to which the -OH group is attached.

 H  1-Butanol 2- butanol 2- Methyl-2-Propanol  (a primary alcohol) (a secondary alcohol) (a tertiary alcohol)  Alcohol with 2 OH groups are: called glycol.  Ethylene glycol  (IUPAC name: 1,2-ethanediol)

 Alcohol with 3 OH groups are: called glycerol  IUPAC name: (1,2,3-propanetriol)

 An ether is a compound formally obtained by replacing both H atoms of H 2 O by the hydrocarbon groups R and R\.  R-O-R\.  CH 3 -O-CH 3 Dimethyl ether  CH 3 -O-C 2 H 5 Ethyl methyl ether (important for surgery operations) C 2 H 5 -O-C 2 H 5 Diethyl ether  Is a volatile liquid used as a solvent and as an anesthetic.

 Aldehydes and ketones are compounds containing a carbonyl group.  A) An aldehyde is :a compound containing a carbonyl group with at least one H atom attached to it.

 Propionaldehyde (propanal)  The aldehyde function is usually abbreviated - CHO,  And the structural formula of acetaldehyde is written CH 3 CHO.

 A ketone is a compound containing a carbonyl group with two hydrocarbon groups attached to it.  The ketone functional group is abbreviated – CO –, and the structural formula of acetone is written CH 3 COCH 3.  Examples:

 You first locate the longest carbon chain containing the carbonyl group to get the stem hydrocarbon name.  Then you change the -e ending of the hydrocarbon to -al for aldehydes  And -one for ketones.  In the case of aldehydes, the carbon atom of the -CHO group is always the number-1 carbon.  In ketones, however, the carbonyl group may occur in various nonequivalent positions on the carbon chain, so, the position of the carbonyl group is indicated by a number before the stem name.

 A) A carboxylic acid: is a compound containing the carboxyl group, -COOH.  These compounds are named by IUPAC rules like those for the aldehydes, except that the ending on the stem name is -oic, followed by the word acid.  The carboxylic acids are weak acids.  Examples: Butyric acid (butanoic acid)

 These red ants, like other ants, make the simplest of the organic acids, formic acid. The sting of bees, ants, and some plants contains formic acid, along with some other irritating materials. Formic acid is HCOOH.

 The general structure is:  Examples:  1) Ethyl acetate  IUPAC (ethyl ethanoate)  2) Methyl acetate  IUPAC (methyl ethanoate)  Esters are important in soap industry.

 Most organic bases are amines.  A) Amines: are compounds that are structurally derived by replacing one or more hydrogen atoms of ammonia with hydrocarbon groups.  Examples: Ethyl amine  (a primary amine)  Dimethyl amine  (a secondary amine)  Trimethyl amine  (a tertiary amine)

 Amides are: compounds derived from the reaction of ammonia, or of a primary or secondary amine, with a carboxylic acid.  For example: