Organic Chemistry Discussion PDF

ORGANIC CHEMISTRY GENERAL CHEMISTRY 2  ORGANIC CHEMISTRY It is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds. Carbon is now known to form a seemingly unlimited number of compounds. The uses of organic compounds impac...

ORGANIC CHEMISTRY GENERAL CHEMISTRY 2  ORGANIC CHEMISTRY It is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds. Carbon is now known to form a seemingly unlimited number of compounds. The uses of organic compounds impact our lives daily in medicine, agriculture, and general life.  Bonding in the Carbon Compounds The property of carbon that makes it unique is its ability to form bonds with itself and therefore allows a large number of organic chemicals with many diverse properties. Carbon has the property of forming single, double and triple bonds with itself and with other atoms. This multiple bond ability allows carbon compounds to have a variety of shapes.  ORGANIC COMPOUNDS The compounds in solid, liquid or gaseous states which contain carbon in their molecule are known as organic compounds. Organic compounds are seen in a number of formats, including Lewis structures, space-filled models, and structural formulas. It is not uncommon to view the hydrogens as lines or to leave them all together in a structural formula of an organic molecule. They are understood to be present in order to complete the 4-bonds provided by the carbon atoms.  INORGANIC COMPOUNDS An inorganic compound is a chemical compound lacking both carbon-carbon (C-C) and carbon-hydrogen (C-H) covalent bonds. Most inorganic compounds are ionic compounds. This means that the chemical bond that holds the atoms together is an ionic bond. Based on inorganic compound constituents, ionic compounds could be classified into bases, acids, and salts.  Open Chain Compounds These compounds are also known as aliphatic compounds, they have branched or straight chains.  Cyclic Compounds  These are cyclic compounds which contain carbon atoms connected to each other in a ring (homocyclic).  When atoms other than carbon are also present then it is called heterocyclic.  (a) Benzenoid aromatic compounds Aromatic Compounds  They are a special type of compound that contains benzene (b) Non-benzenoid aromatic compounds and other ring-related compounds.  Similar to alicyclic, they can also have heteroatoms in the ring. Such compounds are called heterocyclic aromatic compounds.  Functional Groups Functional groups are specific groupings of atoms within molecules that have their own characteristic properties, regardless of the other atoms present in a molecule.  Hydrocarbons Hydrocarbons are organic compounds that are entirely made up of only two kinds of atoms – carbon and hydrogen. The molecular formula of a hydrocarbon can be identified through the number of carbon and hydrogen with the basic formula CxHy.  Saturated Hydrocarbons In these compounds, carbon-carbon atoms and carbon-hydrogen atoms are held together by single bonds. These single-bonded compounds are the simplest hydrocarbons. These types of hydrocarbons don’t have double or triple bonds. These hydrocarbons are called alkanes which have a general formula of CnH2n+2.  Unsaturated Hydrocarbons These compounds consist of a single, double or triple bond between carbon-carbon atoms. The double-bonded compounds are called alkenes, and the triple-bonded compounds are called alkynes. The general formula for alkenes is CnH2n, and for alkynes, the general formula is CnH2n-2. Alkene Alkyne  Cycloalkanes These hydrocarbons possess one or multiple carbon rings. The hydrogen atom is attached to the carbon ring. Cycloalkanes are cyclic hydrocarbons, meaning that the carbons of the molecule are arranged in the form of a ring. Cycloalkanes are also saturated, meaning that all of the carbons atoms that make up the ring are single-bonded to other atoms (no double or triple bonds). The general formula for cycloalkane is CnH2n.  Aromatic Hydrocarbons The aromatic hydrocarbons are “unsaturated hydrocarbons which have one or more planar six-carbon rings called benzene rings, to which hydrogen atoms are attached”. Many aromatic hydrocarbons contain a benzene ring (also referred to as an aromatic ring). The benzene ring is stabilized by resonance and the pi electrons are delocalized in the ring structure. The aromatic hydrocarbons which do not contain a benzene ring are commonly referred to as heteroarenes.  Aliphatic Hydrocarbon Aliphatic hydrocarbons are hydrocarbons that do not contain aromatic rings. They are made entirely of carbon and hydrogen atoms. They can be saturated or unsaturated hydrocarbons. They can also be linear open chain, branched, or cyclic. Aliphatic hydrocarbon is a generalized identification for alkane, alkene, and alkyne.  Alkyl Halide An alkyl halide is an organic compound in which one or more halogen atoms are substituted for one or more hydrogen atoms in a hydrocarbon. The general formulas for organic molecules with functional groups use the letter R to stand for the rest of the molecule outside of the functional group. Because there are four possible halogen atoms (fluorine, chlorine, bromine, or iodine) that can act as the functional group, we can use the general formula R−X to represent an alkyl halide.  Rules in Naming Alkyl Halide 1. Name the parent compound by finding the longest continuous carbon atom chain that also contains the halogen. Add a prefix for the particular halogen atom. 2. The prefixes for each of the four halogens are fluoro-, chloro-, bromo-, and iodo-. If more than one kind of halogen atom is present, put them in alphabetical order. If there is more than one of the same halogen atom in a compound, use the prefixes di-, tri-, or tetra- before the prefix for the halogen.  Rules in Naming Alkyl Halide 3. As with branched hydrocarbons, start numbering the parent carbon chain on the end that will give the substituents the lowest possible numbers. 4. If there are multiple substituents, it is the sum of the numbers that should be considered. If different halogens are present in equivalent positions, give the lower number to the one that comes first in alphabetical order.  Rules in Naming Alkyl Halide 5. Add the numerical prefix into the name before the halogen prefix. 6. Separate numbers with commas and separate numbers from names or prefixes with a hyphen. There are no spaces in the name. Examples of Alkyl Halides  Alcohols An alcohol is an organic compound that contains one or more hydroxyl (−OH) groups. The general formula for alcohols is R−OH. Do not confuse alcohols with inorganic bases that contain the hydroxide ion (OH−). The –OH group in alcohol is covalently bonded to a carbon atom and does not ionize in solution.  Rules for Naming Alcohols 1. Name the parent compound by finding the longest continuous carbon atom chain that also contains the hydroxyl group. 2. If there is one hydroxyl group in the molecule, change the final –e in the name of the alkane to –ol. If there is more than one hydroxyl group, use the full name of the alkane and add a suffix to indicate the number of hydroxyl groups. For example, two hydroxyl groups is –diol, three is –triol, etc.  Rules for Naming Alcohols 3. Number the parent carbon chain in a way that makes the sum of hydroxyl numbers as low as possible. 4. Add the numerical prefix into the name before the name of the alcohol. 5. Separate numbers with commas, and separate numbers from names or prefixes with hyphens. There are no spaces in the name. Examples of Alcohols Aliphatic alcohols can be classified according to the number of R groups attached to the carbon with the hydroxyl group. If one R group is attached to that carbon, the alcohol is a primary alcohol. If two R groups are attached, the alcohol is a secondary alcohol. If three R groups are attached, the alcohol is a tertiary alcohol.  The simplest aromatic alcohol consists of a benzene ring in which one of the hydrogen atoms has been replaced by the hydroxyl group. The name of this compound is phenol.  Ether An ether is an organic compound in which two hydrocarbon groups are bonded to the same oxygen atom. An ether is represented by the general formula R−O−R’. The R’ in the formula means that the second hydrocarbon group (R') may be different from the first one (R).  Rules in Naming Ethers 1. The word ether appears at the end of the name. 2. The two hydrocarbon groups are named using the rules for alkyl substituents, and these names come before the word ether. 3. If the two alkyl groups are the same, the prefix di- is used. If the two alkyl groups are different, they are listed in alphabetical order. 4. Spaces are left between the names of the alkyl groups (if different) and before the word ether.  Aldehyde An aldehyde is a common functional group in organic chemistry and a class of organic compounds. In addition, they are primarily derivatives of alcohol. Aldehydes are responsible for natural and synthetic hormones. The structure of an aldehyde consists of a carbonyl group single bonded to a hydrogen atom. The carbonyl carbon is double-bonded to an oxygen atom, and it is bonded to another hydrogen atom or a carbon-hydrogen chain (shown as the R group in the molecule). An aldehydes position is at the end of a compound due to it requiring a hydrogen bond.  Rules in Naming Aldehydes 1. The “-e” suffix is removed from the parent alkane chains and replaced with “-al”. 2. However, if the aldehyde attaches to a ring, the “-carbaldehyde” suffix adds to the parent alkane name instead. The functional group of an aldehyde is always located at the lowest possible position number, so it is not included in the name.  Ketones Ketones are a common functional group in organic chemistry. Ketones have important physiological properties. As a result, they are a part of several sugars and compounds involved in medicinal use such as cortisone, an anti- inflammatory. One common ketone is acetone (CH3COCH3). Acetone is soluble in water and can dissolve many organic compounds. It has a low boiling point of 56℃ which allows it to be removed from reactions by evaporation. It is commonly involved in industrial solvents such as paint strippers and nail-polish removers.  Rules in Naming Ketones 1. Name the parent compound by finding the longest continuous chain that contains the carbonyl group. Change the –e at the end of the name of the alkane to –one. 2. Number the carbon atoms in the chain so that the carbonyl group has the lowest possible number. 3. Add the numerical prefix into the name before the name of the ketone. 4. Use a hyphen between the number and the name of the ketone.  Carboxylic Acids Organic acids such as acetic acid all contain a functional group called a carboxyl group. The carboxyl group consists of a carbonyl group (C=O) in which the carbon is also bonded to a hydroxyl (−OH) group.  Carboxylic Acids A carboxylic acid is an organic compound that contains the carboxyl functional group. The general formula for carboxylic acid can be abbreviated as –COOH. In addition to the carbonyl oxygen and the hydroxyl group, the carbon atom of the carboxyl group may be attached to a hydrogen atom or to a carbon chain.  Rules in Naming Carboxylic Acids 1. Find the longest continuous chain that contains the carboxyl group and name the parent chain. 2. Change the –e at the end of the name of the alkane to –oic acid. Because a carboxyl group must be at the end of a chain, no numbers are needed to indicate its position. 3. If other substituents are present, number the parent chain so that the carboxyl carbon atom is first.  Ester An ester is an organic compound that is a derivative of a carboxylic acid in which the hydrogen atom of the hydroxyl group has been replaced with an alkyl group. Esters are very commonly found in plants and are responsible for many distinctive odors and flavors. For example, methyl salicylate has the odor and flavor of oil of wintergreen, while propyl ethanoate smells and tastes like a pear. Ester General Formula  Rules in Naming Esters 1. Identify and name the alkyl group (R’) that has replaced the hydrogen of the hydroxyl group. This is the first part of the ester name. 2. Name the carboxylic acid portion of the molecule (R-COO), but change the ending of the name from –oic acid to –oate. This is the second part of the ester name. 3. Leave a space between the alkyl group name and the name of the carboxylic acid derivative.  Amines An amine is an organic compound in which one or more of the hydrogen atoms of ammonia (NH3) is replaced by an alkyl group. The general structure of an amine can be abbreviated as R−NH2, where R is a carbon chain. Like alcohols, amines are often referred to as primary, secondary, or tertiary.  Amines However, in the case of amines, this classification tells you how many alkyl chains are attached to the nitrogen atom. The nitrogen atom of a primary amine is bonded to two hydrogen atoms and one carbon, the nitrogen atom of a secondary amine is bonded to one hydrogen and two carbons, and the nitrogen atom of a tertiary amine is bonded to three carbon atoms.  Primary Amine In a primary amine, one hydrogen is replaced by a different organic group and two hydrogens are bonded to the nitrogen. This molecule is also referred to an an amino group. Secondary Amine A secondary amine has two hydrogens replaced by a different group and one hydrogen remains.  Tertiary Amine Tertiary amines have all hydrogens replace by other organic groups.  Rules in Naming Amines 1. Name the alkyl groups that are attached to the nitrogen atom of the amine. If there is more than one different alkyl group, put them in alphabetical order. If there are two or three of the same alkyl group, use the di− or tri− prefix. 2. Follow the alkyl group name with the suffix –amine, with no spaces.