There are 26-1 organic compounds and 26-5 Alkenes and Alkynes.
Newman projections can be used to represent the possible conformations of an alkane.
The chair of cyclohexane has two hydrogens.
The R, S system is used to name organic compounds.
The E, Z system of nomenclature can be used to identify stereoisomers of alkenes.
Name the key characteristics of aromatic hydrocarbons according to IUPAC rules.
Discuss the structure, function, and synthesis of organic compounds.
Determine the degree of unsaturation and suggest a plausible structure for the formula.
Coffee beans have a compound known as caffeine.
The central nervous system is made up of the brain and nervous system.
The study of compounds only from living matter was thought to have the "vital force" needed to make these compounds.
Even though it had the same composition, the white crystalline solid he obtained from the solution had no properties.
J. J. Berzelius was excitedly told by Wohler that he could make urea without the use of a kidneys.
Since that time, chemists have synthesised millions of organic compounds, keeping in mind, and today organic compounds represent 98% of all known chemical.
In this chapter, we explore some of the principal types of organic propane is sp3 as in methane, following on from the introduction to organic C atoms in ethane and compounds in Chapter 3.
The preparation and use of the C atoms in alkanes means these compounds.
In the next chapter, we will look at reactions that the propane chain is not interconverting compounds.
The number and variety of organic compounds account for the nearly infinite number of possible bonding arrangements of C atoms.
Methane is the chief component of natural gas.
The H atoms are similar to the C atoms in that they are attached by bonds of equal strength.
The bonds are close to 109.5deg.
The number of C structure should be increased.
In this chapter, we will encounter two types of isomers, constitutional isomers and stereoisomers, but our focus is on constitutional isomers.
There is a single chain of four carbon atoms.
The second carbon was bonded to the CH3 group.
A straight-chain hydrocarbon is an example of a branched-chain one.
Both butane and methylpropane have different structural formulas and have different physical properties.
The boiling point of butane is -0.5 degC and that of methylpropane is -11.7 degC.
The number of constitutional isomers increases with the number of carbon atoms.
In Chapter 3, we talked about a way to simplify the writing of organic structures.
There is a C atom wherever a line ends or meets another line.
Short side chains are attached to the carbon atom of the longest chain, as is the case for structures (2) and (3).
The origin or properties of new compounds were assigned to early organic chemists.
Some of the names are still being used.
A system of common names was not feasible as thousands of new compounds were synthesised.
The International Union of Pure and Applied Chemistry recommended one of the interim systems.
In 1874, van't Hoff and Le Bel published papers on the hypothesis that the four bonds from a central carbon extend.
This was the beginning of stereochemistry.
There was only one known compound with the formula CH2X2.
If the orientation of the bonds to a carbon atom is square-planar, determine the expected number of isomers using the compound CH2F2 as an example.
To give each C atom four bonds, we need to write the longest chain of C atoms and add an appropriate number of H atoms.
We look for isomers that have fewer carbon atoms.
There are five carbon atoms in it.
The formula C5H12 has three isomers.
The case of structures (2) and 12?2 was a good example of when two structures are actually the same.
The formula C6H14 is used for the five constitutional isomers.
Write structural formulas for the nine constitutional isomers with the formula C7H16.
We will only consider hydrocarbons with all carbon-to-carbon bonds as single bonds.
The first few are CH4, methane, C2H6, ethane, and propane.
Ohio has two constitutional isomers.
The University of Wisconsin, Stevens Point has three structural isomers for the C5H12 alkanes.
J. Shulfer must consider the nature of some of the possible side chains to be able to name molecules that have even greater complexity.
Sidney had one hydrogen atom removed.
The propyl group is 100th anniversary of CH2 CH2 CH3.
A substituent alkyl group international congress is called an alkyl side chain because it replaces a hydrogen atom in the main chain.
A systematic shows some alkyl groups.
An abbreviation for compounds was adopted.
Carbon atoms at the end of an alkane chain are the primary carbons.
The hydrogen atoms are labeled the same.
The formation of a secondary alkyl group and quaternary is caused by the removal secondary, tertiary, and of a secondary hydrogen.
As long as we apply the rules in sequence, we can name branched-chain hydrocarbons.
The main branch should be considered a substituent alkyl group.
Table 26.1 has the names of alkyl substituents.
The number of the C atom attached to each substituent and its chemical identity are what you should name it.
It's not ignored when deciding the alphabetical order.
The CH3 quaternary carbon atom is shown in red.
There are elements in organic compounds.
We follow the rules listed above.
With practice, you will be able to apply the rules.
The side-chain substituents are shown in blue and the C atoms are numbered in red.
The longest chain of C atoms is five, and the carbons are numbered so that the one with two substituent groups is number 2 instead of number 4.
Two groups are on the second C atom, and one group is on the fourth C atom.
2,2,4-trimethylpentane is the correct name.
The name 2,4,4-trimethylpentane would have been obtained if we numbered the C atoms from right to left.
Give an IUPAC name for CH3 CH2 CH1 CH32 CH2 CH2C1 CH322 CH2
Give an IUPAC name for CH3CH2 CH1 CH32 CH2 CH2
There are two substances positioned at carbons 4 and 2.
The C chain of atoms is seven.
On the left, we attach a group to the second C atom.
To check the answer, we use the rules given on page 1211 to name the structure we've drawn.
We need to get the name that was given.
There is a formula for 3-ethyl-2,6-dimethylheptane.
There is a formula for 3-ethyl-2,4-dimethylpentane.
The major types of organic compounds have their functional groups shown in red.
The physical and chemical properties of organic compounds are dependent on the functional groups present.
Similar chemical properties can be found in compounds with the same functional group.
One way to study organic chemistry is to consider the properties of functional groups.
A functional group takes the place of an H atom in a ring.
Such is the case with alcohols and alkyl halides.
When naming the compound, we include the carbon number for the br substituent.
The carbon number is placed before the part of the name that relates to it.
In this chapter, we will focus on the structures and properties of several classes of organic compounds.
Some of their characteristic reactions will be the focus of the next chapter.
Section 3-7 is useful to review.
Some of the properties of the alkanes will be explored in this section.
The complexity of the alkanes range from methane to fifty C atoms.
Water-insoluble compounds in the series are closely related to chemical and physical properties.
The data shows that the boiling points of alkanes are related to polarizabilities and shapes.
The strongest intermolecular attractions are between the straightchain molecules.
The boiling points of idomers with more compact structures are lower.
Write a homologous series for alkyl halides to show the meaning.
Ball-and-stick models allow us to see an important type of motion in alkane molecule--rotation of groups with respect to one another.
One conformation can be converted into another.
The bonds to the hydrogen atoms are visible even though the carbon atom is obscured by the one in front.
The rear carbon atom is obscured by the front carbon atom on the C axis.
The front carbon is located at the intersection of the three arms of the inverted Y and the rear carbon is represented by a circle in the Newman projection.
The carbon atom is depicted by a circle and its bonds project from the outer edge of the circle.
Newman projections are used to represent the many different spatial arrange these representations in 1952 ments of atoms.
The H atoms are organic.
The first and second carbon atoms are in front of each other on the C axis.
The three rear hydrogen atoms are drawn slightly out of the perfectly eclipsed position to make them more visible in the Newman projection.
The potential maps for the staggered and eclipsed ethanes are shown in the margin.
The hydrogen atoms are as close to one another as possible in the staggered and eclipsed versions.
The energy required to convert from the staggered conformation to the eclipsed one is about 12.0 kJ mol-1.
We talked about C in Chapter 12.
Potential energy diagram for the internal rotation of the methyl groups in ethane temperature.
The electrons in the bonds experience increased repulsion.
The dihedral angle is the angle of rotation about the carbon- carbon bond shown in the margin.
The molecule is in the staggered conformation when it is 0deg, and it is in the eclipsed conformation when it is 60deg.
4.1 kJ mol-1 is contributed by H bond interaction.
The next member of the homologous series is the C bond in propane.
The diagram of propane's potential energy is similar to that of ethane.
Newman projections can help us understand the difference.
A new group of H atoms has been created.
Butane is the next member of the series.
There are conformers that can be formed.
The C3 bond can be identified.
Anti and gauche are distinct staggered conformations.
The lowest energy structure reduces the repulsions among the substituents.
There is a structural diagram for 2,3-dimethylpentane.
C2 has a hydrogen atom and two methyl groups.
Three different groups are bonding to C3: a hydrogen atom, a methyl group, and an ethyl group.
The lowest energy is the one where the alkyl groups are staggered.
The number of gauche interactions between the larger groups should be minimized.
First, we draw a circle to represent the rear carbon, and then we add lines for the bonds formed by the front carbon atom.
We add lines for the bonds formed by the rear carbon atom.
The groups will be attached to construct 2,3-dimethylpentane.
Add two groups and a hydrogen atom to the carbon atom.
Conformation has two gauche interactions, but the other two have three.
The lowest energy can be found in the structure (a).
We looked at rotation about a carbon-carbon bond.
We will not consider the fact that other carbon-carbon bonds also occur at the same time.
In order to increase energy, rank the conformations by lowest to highest.
At the end of this section, we describe the main source of alkanes, as well as several laboratory methods that can be used to prepare them.
In the presence of a metal catalyst such as Pt, Pd, or Ni, unsaturated hydrocarbons, whether containing double or triple bonds, may be converted to alkanes by the addition of H atoms to the multiple bond systems.
The metals play a role in the production of alkanes of double the carbon content in another type of reaction.
The carboxylic acids can be fused with the metal salts.
The metal carboxylate and the alkane with one carbon less than it are formed.
Natural gas contains the lower mass alkanes.
Liquefied petroleum gas (LPG) can be sold as propane and butane.
A complex mixture of at least 500 compounds is used to make higher alkanes.
The main fractions are listed in Table 26.4.
Some hydrocarbons burn more smoothly than others, so they aren't as desirable.
There is a reference system for rating gasoline.
An octane rating can be assigned if the mixture matches the performance characteristics of the gasoline being tested.
An octane number of 87 is assigned to a gasoline that gives the same performance as a mixture of 87% 2,2,4-trimethylpentane and 13% heptane.
Branchedchain hydrocarbons have higher octane ratings than their straight-chain counterparts.
If you want to use gasoline in automobiles, you should use fuels with octane numbers near 90.
Modifications of the gasoline fraction are required.
The molecule C15H32 might be broken down into C8H18 and C7H14.
Adding antiknock compounds to prevent premature combustion can improve the octane rating of gasoline.
At one time, it was the preferred Additive.
In most countries, lead is no longer used in gasoline because it is toxic.
The formula CnH2n+2 is used for alkanes in chain structures.
We can think of the rings as having formed after the elimination of an H atom from each end of a straight-chain alkane.
The formula CnH2n is used for simple cycloalkanes.
The line-angle representations at the bottom of page 1221 might lead you to believe that the carbon atoms in cycloalkanes all lie in the same plane.
This is not usually the case.
The only cycloalkane in which carbon atoms form a ring is cyclopropane.
The rules on page 1211 can be used to name a cycloalkane with substituent groups.
The cyclopropane bond angles are 60 degrees.
C bonds in cyclopropane are weaker than they are in propane and other straight-chain alkanes, and cyclopropane is more reactive than a straight-chain alkane.
The FIGURE 26-10 cycloalkanes show the heats of combustion of propane, butane, pentane, and hexane.
The ball-and-stick model has a ring strain.
C bonds that link together CH2 groups in cycloalkanes are the same as overlap of the orbitals and they are in straight-chain alkanes.
When a compound is burned, the ring strain's energy is released as heat, which is more negative than expected.
Table 26.5 shows the C energy tal heats of combustion for a few cycloalkanes.
A measure of 289 kJ mol-1 is provided by the dif in cyclopropane.
The ring strain in the cycloalkanes is shown in the substantially smaller table.
The cyclo 347 kJ mol-1 is free of ring strain.
The data shows that cyclopropane and cyclobutane have a lot of ring strain.
For example, C/combH1butane2 - C/combH1propane2 is equal to 661 kJ mol-1.
The cyclobutane and the cyclopentane molecule give rings that are puckered rather than planar, FIGURE 26-11 as shown below.
Two of the molecules are important for cyclohexane.
The chair is more stable than the boat.
We will not discuss the other conformations of cyclohexane.
They can be seen in more advanced organic chemistry courses.
The ring in a cycloalkane has two faces, one of which is adjacent to the other.
If we focus on the hydrogen atoms bonding to the rearmost carbon, we can see that one of the hydrogen atoms is above the three carbon atoms and the other is below the plane.
One hydrogen atom is next to the upper face and the other is next to the lower face.
The H atoms are shown in blue.
Various isomers are possible if the structures of Organic Compounds on different carbon atoms are replaced by other substituents.
Many isomers are possible for disubstituted cycloalkanes.
For example, consider chloromethylcyclohexane.
Draw dashed and solid wedge line structures for the trans isomers.
The chair and boat forms of cyclohexane have the same bond angles.
The chair form of cyclohexane has slightly lower energy.
To answer this question, we will first describe how to draw the chair form of cyclohexane and then use a Newman projection to provide insight needed.
There are two parallel lines that are slightly tilted.
The cap points upward.
The upper ends should be connected with a cap.
The hydrogen atoms point in the same direction as the carbon atoms.
The bonds to the hydrogen atoms are parallel to an imaginary axis that passes through the center of the ring.
The ring directs the bonds to the hydrogen atoms sideways.
The hydrogen atoms alternate points as we move around the ring.
There is a change for the hydrogen atoms.
C bonds are not the same.
Many concepts are being discussed in this section.
The carbon-hydrogen bonds are staggered.
The chair form is less stable than the boat form, because some of the carbon-hydrogen bonds in the boat form are eclipsed.
A ring flip is an interconversion.
When the ring flips from one chair to another, the hydrogen in one chair becomes the hydrogen in the other chair, and vice versa.
100,000 ring flips per second are what the cyclohexane ring undergoes at room temperature.
When H atoms in cyclohexane are replaced by substituents, the chair conformations no longer have the same energy.
H C1 is moving upward.
C4 is moving downward.
Two of the H atoms are shown in red to emphasize that when the cyclohexane ring converts from one chair to another, the equatorial hydrogen atoms are converted into axial hydrogen atoms.
The boat form is a part of the interconversion of the two chair forms.
The energy differences between the two forms of cyclohexanes have been measured.
The ferences are given in Table 26.6.
The size of the Between Axial and group increases the energy differences between the two forms.
The axial conformer is only a small part of the Mono-Substituted molecules.
They compete for the position at the equator.
Some isomers of dimethylcyclohexane are compared.
The CH cyclohexane is divided into two groups.
The chair conformations shown below have two different groups.
There is a 14.2 kJ mol-1 difference between the two methyl groups in the equatorial position and the one in the axial position.
This energy difference is twice as large as the one in Table 26.6.
We drew a cyclohexane ring showing the two bonds but without the substituents added to the ring.
We look at the placement of the substituents.
There is a relationship between the bonds on the odd and even numbered carbon atoms when the cyclohexane ring is numbered.
Only if the two carbon atoms have both bonds up or down is this possible.
The lowest energy will have the methyl groups in the equatorial positions.
If the molecule above undergoes a ring flip, the methyl groups will be in the axial positions and the resulting conformation will be higher in energy.
There are different structures and properties of idomers.
The same formula is used for these molecules.
These are stereoisomers that are not enantiomers.
Isomerism is summarized in cycloalkanes.
When an organic compound has an asymmetric carbon, it can arise.
Molecules with asymmetric carbon cannot be interconverted without breaking and reforming bonds.
In Chapter 28, we will see that the molecule with asymmetric carbon atoms is important in biochemistry.
A solution of an active compound can change the plane of light.
The asymmetric molecule is required for optical activity because its mirror image cannot be superimposed on the original molecule.
The C atom has four different groups attached to it.
There are two nonsuperimposable isomers of 3-methylhexane in the illustration.
The four dif of the other enantiomer ferent substituent groups are connected by an atom.
This type of center is site direction.
Sometimes with a 50:50, it is referred to as an asterisk.
Molecules with one stereocenter are always mixed with the other.
In Chapter 28, we will see that a racemic stereocenter can incorporate more than one enantiomer.
There is no rotation of the plane of light in Chapter 27.
Determine if either 2-chloropentane or 3-chloropentane is a Chiral Molecule.
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