Organic Chemistry Chapter 9 Flashcards

Questions and Answers

What do alcohols, epoxides, and ethers have in common?

They are all non-polar

They all have polar C-O sigma bonds (correct)

They are all gases at room temperature

They contain a carbonyl group

What do alcohols contain?

A hydroxy group (OH) bonded to a sp3 hybridized carbon.

What do enols contain?

An OH group on a sp2 hybridized carbon of a C-C double bond.

What do phenols contain?

An OH group on a benzene ring. Signup and view all the answers

What is an ether characterized by?

Contains 2 alkyl groups bonded to an oxygen atom. Signup and view all the answers

A symmetrical ether has two different alkyl groups.

False Signup and view all the answers

Both alcohols and ethers are organic derivatives of H2O.

True Signup and view all the answers

What is an epoxide?

An ether having the oxygen atom in a three-membered ring. Signup and view all the answers

What is the hybridization of oxygen in alcohols, ethers, and epoxides?

sp3 hybridized. Signup and view all the answers

The bond angle around the O in an alcohol and ether is ____.

109.5° Signup and view all the answers

The C-O-C bond angle of an epoxide is ____.

60° Signup and view all the answers

What suffix is used to identify alcohols in the IUPAC system?

-ol Signup and view all the answers

When an OH group is bonded to a ring, the ring is numbered ending with the OH group.

False Signup and view all the answers

What are the two steps in naming an alcohol according to IUPAC?

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How do you assign simple alcohols a 'common name'?

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What are diols or glycols?

Compounds with two OH groups. Signup and view all the answers

What are triols?

Compounds with three OH groups. Signup and view all the answers

How do you name simple ethers?

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How do you name a complex ether?

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What are the three ways to name an epoxide?

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How do you name an epoxide as an epoxyalkane?

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How do you name an epoxide as an oxirane?

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How do you name an epoxide as an alkene oxide?

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What interactions do alcohols, ethers, and epoxides exhibit?

Dipole-dipole interactions. Signup and view all the answers

Alcohols are much more polar than ethers and epoxides.

True Signup and view all the answers

Increasing the number of R groups around the carbon bonded to OH does what to the extent of hydrogen bonding?

Decreases. Signup and view all the answers

What are two ways to increase the boiling point of alcohols, ethers, and epoxides?

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Determine the solubility conditions for alcohols, ethers, and epoxides:

Having <= 5C's = H2O soluble Having > 5C's = H2O insoluble Signup and view all the answers

In the host-guest complex known as the crown ether-cation complex, who is the host and who is the guest?

The crown ether is the host and the cation is the guest. Signup and view all the answers

What is molecular recognition?

The ability of a host molecule to bind to a specific guest. Signup and view all the answers

Alcohols and ethers are common products of what reaction?

Nucleophilic substitution. Signup and view all the answers

Alcohols and ethers are synthesized from alkyl halides in what type of reactions?

SN2 reactions using strong nucleophiles. Signup and view all the answers

What is the Williamson Ether Synthesis?

Formation of an ether from the reaction of an alkoxide ion with an alkyl halide. Signup and view all the answers

Which path is preferred for synthesizing unsymmetrical ethers?

The path that uses the less sterically hindered halide. Signup and view all the answers

What type of nucleophile is needed to synthesize an alcohol?

Hydroxide. Signup and view all the answers

What type of salt is needed to make an ether?

Alkoxide. Signup and view all the answers

A halohydrin can perform what type of reaction to form an epoxide?

Intramolecular reaction. Signup and view all the answers

Alcohols and alkyl halides both contain good leaving groups.

False Signup and view all the answers

Why does nucleophilic substitution with ROH not work?

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What must happen for an alcohol to undergo a substitution reaction?

The OH group must first be converted into a better leaving group by reacting with a strong acid. Signup and view all the answers

When the alcohol is treated with a strong acid, what does the -OH get converted to?

H2O. Signup and view all the answers

What is dehydration?

A β elimination reaction where OH & H are removed from the α & β carbons respectively. Signup and view all the answers

As the substitution of an alcohol increases, what happens to the rate of dehydration?

The rate of dehydration increases. Signup and view all the answers

What product is considered the major product in dehydration reactions?

The most substituted alkene. Signup and view all the answers

What elimination mechanism do 2° & 3° alcohols undergo?

E1. Signup and view all the answers

What elimination mechanism do 1° alcohols undergo?

E2. Signup and view all the answers

What are the three steps of a 2°/3° alcohol dehydration?

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What are the two steps of a 1° alcohol dehydration?

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What is Le Châtelier's Principle?

A system at equilibrium will react to counteract any disturbance to the equilibrium. Signup and view all the answers

What is carbocation rearrangement?

A less stable carbocation can rearrange to a more stable carbocation by shifting a hydrogen or alkyl group. Signup and view all the answers

What are the four steps of a 1,2 methyl shift in dehydration?

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In dehydration reactions, what happens when POCl3 is used?

Converts a poor leaving group into a good leaving group. Signup and view all the answers

What is the Protonation of OH from 1° form?

RX by SN2 Mechanism. Signup and view all the answers

What is the Protonation of OH from 2° and 3° form?

RX by SN1 Mechanism. Signup and view all the answers

What affects the reactivity of hydrogen halide?

Increasing acidity. Signup and view all the answers

What Lewis acid catalyst is used when 1° alcohols react with HCl?

ZnCl2. Signup and view all the answers

What kind of stereochemistry do 1° alcohols react in SN2 reaction to form?

Inversion. Signup and view all the answers

What do 3° alcohols yield when reacting in an SN1 Mechanism?

Racemic mixture. Signup and view all the answers

Carbocation rearrangement is possible in the SN1 reactions of 2° and 3° alcohols.

True Signup and view all the answers

What does SOCl2 convert 1° and 2° alcohols into?

Alkyl chlorides. Signup and view all the answers

What does PBr3 convert alcohols into?

Alkyl bromides. Signup and view all the answers

Summarize converting ROH to RX.

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Alcohols are converted to alkyl tosylates by treatment of...

p-toluenesulfonyl chloride in the presence of pyridine. Signup and view all the answers

Since alkyl tosylates have good leaving groups, they undergo...

Both nucleophilic substitution and beta elimination. Signup and view all the answers

Summarize the two-step reaction of an alcohol with TsCl and pyridine.

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Summarize nucleophilic substitution and β elimination of alcohols.

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The leaving groups of ethers can only be converted to good leaving groups by reaction of which strong acids?

HBr or HI. Signup and view all the answers

Since both C-O bonds are broken in an ether, what occurs?

2 nucleophilic substitution reactions occur. Signup and view all the answers

The 2° or 3° alkyl groups of an ether oxygen are cleaved by what mechanism?

SN1 mechanism. Signup and view all the answers

Methyl or 1° alkyl groups are cleaved by what mechanism?

SN2 mechanism. Signup and view all the answers

In the mechanism of an ether with a strong acid HX, what is the first step?

HX protonates the oxygen to make it a good leaving group. Signup and view all the answers

In the mechanism of an ether with a strong acid HX, what is the second step?

HX provides a source of X- for substitution. Signup and view all the answers

Thiols and sulfides are sulfur analogues of what?

Alcohols and ethers respectively. Signup and view all the answers

What happens during nucleophilic attack on an epoxide?

Opens the strained three-membered ring. Signup and view all the answers

What are the two steps to opening an epoxide ring with a strong nucleophile?

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What type of mechanism do strong nucleophiles like -OH, -OR, -CN, -SR, and NH3 use when reacting with epoxides?

SN2 mechanism. Signup and view all the answers

In an unsymmetrical epoxide, where does the nucleophile attack?

Less substituted carbon atom. Signup and view all the answers

If the epoxide is symmetrical, nucleophilic attack occurs from where?

The back side at either C-O forming a racemic mixture. Signup and view all the answers

What are the two steps in the opening of an epoxide ring with H-Z?

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Study Notes

Alcohols, Ethers, and Epoxides

Alcohols, epoxides, and ethers contain polar C-O sigma bonds.
Alcohols feature a hydroxy group (OH) bonded to an sp3 hybridized carbon.
Enols possess an OH group on a sp2 hybridized carbon involved in a C-C double bond.
Phenols have an OH group substituted on a benzene ring.
Ethers consist of two alkyl groups connected to a single oxygen atom.
Symmetrical ethers have identical alkyl groups; unsymmetrical ethers have different ones.

Nomenclature

Alcohols are identified using the suffix -ol in the IUPAC naming system.
To name alcohols, first identify the longest carbon chain with the OH group, then number it to give the OH group the lowest number.
When naming ethers, both alkyl groups should be named and arranged alphabetically; for symmetrical ethers, add the prefix -di.

Properties and Interactions

Alcohols and ethers are derivatives of water formed by replacing hydrogen atoms on the oxygen.
Alcohols, ethers, and epoxides exhibit dipole-dipole interactions, while alcohols can also form hydrogen bonds.
Alcohols are more polar compared to ethers and epoxides, impacting their solubility and boiling points.

Solubility and Boiling Points

Compounds with 5 or fewer carbon atoms are water-soluble; those with more than 5 are organic-soluble only.
The boiling point of alcohols, ethers, and epoxides can be increased by enhancing intermolecular forces and hydrogen bonding.

Synthesis and Reactions

Alcohols and ethers can be synthesized via nucleophilic substitution reactions with alkyl halides, favoring strong nucleophiles and primary halides for optimal yield.
Williamson Ether Synthesis involves the reaction of alkoxide ions with alkyl halides to form ethers.
Unsymmetrical ethers are synthesized preferably using less sterically hindered halides.

Dehydration and Elimination Reactions

Dehydration involves the elimination of OH and H, moving to create alkenes, where the most substituted alkene is the major product.
For 2° and 3° alcohols, the E1 mechanism is followed, while 1° alcohols undergo the E2 mechanism.

Carbocation Rearrangements

Carbocation rearrangement can occur in reactions involving 2° and 3° alcohols to form more stable carbocations.

Reactions with Acids

Alcohols convert to better leaving groups by reacting with strong acids like HCl or H2SO4.
The mechanism for converting primary alcohols involves an SN2 pathway, resulting in inversion of configuration, while 3° alcohols form a racemic mixture via SN1 mechanism.

Rearrangement and Reactions of Ethers

Ethers react with strong acids to generate two nucleophilic substitution reactions, breaking C-O bonds.
Thiols and sulfides serve as sulfur analogues to alcohols and ethers, respectively.

Nucleophilic Attack on Epoxides

Nucleophilic attack on epoxides involves opening a three-membered ring structure, often at the less substituted carbon atom in unsymmetrical epoxides.
The reaction mechanism typically follows SN2 pathways with strong nucleophiles leading to ring-opening.

Summary and Conclusion

A comprehensive understanding of alcohols, ethers, and epoxides involves their structures, physical properties, naming conventions, synthesis routes, and distinctive reactivity patterns.
Mastery of these concepts is essential for navigating organic chemistry topics effectively.

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Description

Test your knowledge of key concepts in Organic Chemistry Chapter 9 with these flashcards. This chapter covers important functional groups such as alcohols, epoxides, ethers, and phenols. Study the definitions and properties to enhance your understanding of organic compounds.