Alcohol, Phenol,And Ethers:

“Their Structures, Physical Properties and Nomenclature”

Mr. Blithe

Topic:

Structure and Physical Properties

ALCOHOLAn organic compound containing a hydroxyl group attached to an alkyl group.

a non-polar (alkane-like) chain.a polar hydroxyl group.

Alcohols have the general formula: R-OH, where “R” involves a saturated C-atom (bound to hydrogen's and/or other carbons).For example:

Classification of alcohols

• Alcohols may be classified as 1o (Primary), 2o (Secondary), or 3o (Tertiary), by considering the number of carbons bound to the hydroxyl-bearing carbon.

•Ethanol is a primary alcohol because there is only one alkyl group attached to the carbon that carries the  OH substituent. •The isopropyl alcohol found in rubbing alcohol is a secondary alcohol, •An example of a tertiary alcohol is tert-butyl (or t-butyl) alcohol or 2-methyl-2-propanol.

RCH2OH R3COHR2CHOH

R-O-H has a structure similar to that of water

Higher boiling points.Hydrogen Bond in Water

Hydrogen Bond in Alcohol

Classification of alcohols

SolubilityThe Lower the molecular weight of alcohols, the higher

the solubility in water.The water-solubility of alcohols depends on the length of

the alkyl chain in the alcohol. alcohols having chains longer than four carbons are not

very water-soluble. 3-4 carbons or less— ARE soluble in water

Alcohols with more than one hydroxyl group (polyhydroxyl alcohols) have higher boiling points than monohydroxyl alcohols.

We already saw that the boiling points of alkanes increase with increasing chain length. The same is true for alcohols.

O

CH3 H

O

CH3 H

Alcohols having chains SHORTER than four carbons are very water-soluble… Methanol is Soluble and Miscible in water…

Methanol

2HC

-2H

C-2

HC

-3H

C

oH

2HC

-2H

C-2

HC

-3H

Co

HButanol

Alcohols having chains LONGER than Three carbons are not very water-soluble… Butanol is Soluble but not Miscible in water…

Formula Name Solubility in Water (g/100 g)

CH3OH methanol infinitely soluble

CH3CH2OH ethanol infinitely soluble

CH3(CH2)2OH propanol infinitely soluble

CH3(CH2)3OH butanol 9

CH3(CH2)4OH pentanol 2.7

CH3(CH2)5OH hexanol 0.6

CH3(CH2)6OH heptanol 0.18

CH3(CH2)7OH octanol 0.054

CH3(CH2)9OH decanol insoluble in water

Solubilities of ALCOHOL in water

CH3CH2CH2OH

CH3CH2CH2CH3

CH3OHCH3CH3

CH3CH2OH

CH3CH2CH3

CH3CH2CH2CH2OH

CH3CH2CH2CH2CH3

Structural Formula NameMolecularWeight

bp(°C)

Solubilityin Water

methanol 32 65 infiniteethane 30 -89 insoluble

ethanol 46 78 infinite

propane 44 -42 insoluble

1-propanol 60 97 infinite

butane 58 0 insoluble

8 g/100 g117741-butanol

pentane 72 36 insoluble

Comparison between the Boiling points and Solubility of ALKANES and ALCOHOLs

PHENOL

Phenols are compounds in which the hydroxyl group is attached to a benzene ring.

Phenol is the simplest member of a family of compounds in which an -OH group is attached directly to a benzene ring.

Structure Of Phenol

O H

Physical properties

Pure phenol is a white crystalline solid, smelling of disinfectant. The crystals are often rather wet and discolored.Phenols have the formula Ar-OH

Ar must be an aromatic ring (e.g., Benzene)

Widely used in healthcare as: Germicides Antiseptics Disinfectants

Melting and boiling points

high melting and boiling points ...\Documents\Mr. BLITHE\Documents\my files\my academic files (2013-2014)\MY chem reports (organic Chem)\ACTUAL REPORT\attachment.pptx

Hydrogen bonds can form between a lone pair on an oxygen on one molecule and the hydrogen on the -OH group of one of its neighbors.Solubility in water

Phenol is moderately soluble in water - about 8 g of phenol will dissolve in 100 g of water.Phenol is somewhat soluble in water because of its ability to form hydrogen bonds with the water.

ETHERSEthers are a class of organic compounds characterized by an oxygen atom connected to two hydrocarbon groups.Ethers do not H-bond with themselves, so have boiling points similar to hydrocarbonsEthers are only slightly soluble in water and are highly flammable

Structure of ETHERS

 An ether is a characterized by an oxygen bonded to two alkyl or aryl groups, represented here by R and R'.  The substituent's can be, but do not need to be, the same.

Ethers can act as a hydrogen-bond acceptor, as shown in the figure on the right. But, they can't act as hydrogen-bond donors.

Solubility

Less likely to be soluble in water than the alcohol with the same molecular weight.The absence of an -OH group in an ether also has important consequences for its chemical properties.

Ethers are essentially inert to chemical reactions. They don't react with most oxidizing or reducing agents, and they are stable to most acids and bases, except at high temperatures.

However, extremely FLAMMABLE explode if exposed to air for longer periods of time, to form EXPLOSIVE PEROXIDES.

Melting and Boiling points

Boiling points and melting points are dictated by intermolecular forces. Compared with alkane of similar molar mass, an ether will have a similar boiling point. Compared to an alcohol of the same molar mass, the ether will have a much lower boiling point.

Medical use of Ethers

Ethers are often used as anestheticsAccumulate in the lipid material of nerve

cells interfering with nerve impulse transmission.

Today halogenated ethers are used routinely as general anestheticsLess flammableSafer to store and to work with

Nomenclature

ALCOHOL

Name the C-atoms of a single alkyl group as for alkanes.Add the word “alcohol” following a space after the alkyl name.

1) CH3--OH methyl alcohol

For example:

2) CH3 CH2--OH ethyl alcohol

COMMON NAME

IUPAC NAME

CH3CHCHCH3OH

CH3

For example:

Butane

Butanol1234

3-methyl-2-butanol

Try this one:

1. CH3-CH-CH2OH

CH3

2-methyl-1-propanol

Alcohols with more than one OH group

Polyhydroxyl alcohols possess more than one OH group.Alcohols which possess two OH groups are called “diols” and those with three OH groups are called “triols”

Naming this kind of Compound is simple, just follow this:

Alkane name + the number of the OH group

For example:

1. CH2-CH-CH2

OHOH OH

1,2,3-propanetriol

1,2-Ethanediol 1,2-Propanediol 1,2,3-Propanetriol

O HO HO HO H O H O HO H

Naming Alcohols…continuation

1. Name the parent compound.2. Replace the –e with –ol.3. Number the ring to minimize number of carbon with the –OH

group 4. Identify, name, and number all substituent/s.

OH

CH3

For example:

Six Carbon ring= CyclohexaneCyclohexanolnumber counterclockwise

methyl on C-3

Note: OH must be at C-1

3-methylcyclohexanol

PHENOLCompounds with additional substituent's are named as substituted phenolswhen there is only one other substituent, Ortho, Meta or Para are used.

Mono-substituted phenols are characterized using the prefix ortho (o-), meta (m-) or para (p-) depending on the placement of the substituent from the hydroxyl group.

ortho: (1,2-) meta :(1,3-) para : (1,4-)

ClClCl

o-chlorophenol m-chlorophenol p-chlorophenol

If there are two or more additional substituent's, each must be numbered, beginning at the OH and going in direction that gives substituent's lowest numbers (or alphabetical if same in both directions).

The simplest member of phenol is called phenol itself or hydroxybenzene and the rest are named as its derivatives.

Phenol or Hydroxybenzene

Functional group suffix = -common - phenol, systematic - benzenol 

Functional group prefix = hydroxy  di , tri and so forth are used to denote the number of

substituent.

For example:

OH

1,2-dihydroxybenzene

OH1,3-

dihydroxybenzene

CH3

3-methylphenol

NO2

NO2

NO2

2,4,6- trinitrophenol

NOTE: Many have common or trivial names that do not at all suggest the structure…

ETHERSCommon Name

For common names: name each alkyl group attached to the oxygen followed by ether.

For example:

1. CH3-CH2-O-CH2-CH3

Diethyl Ether

2. CH3-CH2-O-CH3 Ethyl methyl Ether

Methyl phenyl Ether

IUPAC NAME

For complex ethers IUPAC names are used

Step1: Name as an alkane, with larger alkyl group being the parent chain.Step 2: Find the smaller alkyl group and the O are named together as an alkoxy group (replace -yl with -oxy)

e.g., CH3CH2O = ethoxyStep 3: Number chain starting at end nearest alkoxy groupStep 4: Use a number to give location of alkoxy group

For example:

CH3CH2CH2CH2CH2-O-CH3

1-methoxypentane

Pentane

Methyl=Methoxy1

Try this one:

1. CH3-CH2-CH2---C---CH2-CH3

CH3

CH3

O

3-methoxy-3methylhexane

Naming Cyclic Ethers

Cyclic ethers are generally named by their common names.A cyclic ether containing two carbons is called ethylene oxide (generally known as epoxides)A cyclic ether containing 4 carbons (with 2 double bonds) is called a furanA cyclic ether containing 5 carbons (with 2 double bonds) is called a pyranA cyclic ether containing 4 carbons and 2 oxygens is called a dioxane

TRIVIA…

PHENOLS are next-generation anti-oxidant found throughout nature in some of the healthiest foods. PHENOLS are the common health-giving link that ties together foods, such as Red Wine, Green Tea, Dark Chocolate, and Super-Berries.

In human health these compounds are thought to be instrumental in combating oxidative stress, a process associated with some neurodegenerative diseases and some cardiovascular diseases.

Approximately 600,000 students per year are assaulted by a drinking student.

Research suggests that women are more vulnerable than men to many alcohol- induced problems. Some of these include, Organ Damage, Trauma, Legal and interpersonal difficulties.

Alcohol affects men and women differently. Women become more impaired than men from drinking the same amount of alcohol. This is because women:• Are generally smaller in size• Have less body water• Have less dehydrogenase.• Have more estrogen

Alcohol is a central nervous system depressant. In small amounts it can have a relaxing effect.

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