Chemistry- Functional Groups, Their Properties, and Reactions

Alkanes Melting and Boiling Points

Alkanes Melting and Boiling Points

• only interact via dispersion forces

• lowest melting and boiling point of all organic molecules

• as molecules become larger, melting and boiling point increase

• branched alkanes have lower boiling point because of their more compact structure (increase in branches decreases boiling point)

Alkanes Solubility

• nonpolar, insoluble

Alkanes Density

• less dense than water

Combustion of Alkanes

reactant- alkane and O2

product- CO2 + H2O + energy

Hydrogenation of Alkenes and Alkynes

• adding 2 hydrogens

• metal catalyst: Pt, Ni, or Pd

• breaks alkenes to alkanes and alkynes to alkenes

Hydration of Alkenes

• addition of water

• requires a strong acid as a catalyst- H2 or H2SO4

• H is added to carbon with larger number of Hs to begin with

Halogenation of Alkenes and Alkynes

• reaction with Cl2 or Br2

• no catalysts needed

• removes double bond and attaches there

Hydrohalogenation of Alkenes and Alkynes

• reaction with HCl or HBr

• no catalyst needed

• H adds to C atom with larger number of Hs

Alcohols Boiling Points

• hydrogen bonding between molecules

• 2nd highest boiling point

• length of chain increases boiling point

Alcohols Solubility

• hydrogen bonds form between alcohols and water

• soluble with 3 or less carbon atoms

• slightly soluble with 4 carbon atoms

• insoluble with 5+ carbon atoms

Ethers Boiling Point

• cannot form hydrogen bonds with itself

• have similar boiling points with alkanes

Phenol Boiling Point

• high boiling point because of hydrogen bonding

• slightly soluble due to aromatic ring

Ethers Solubility

• can hydrogen bond with water

• stronger intermolecular forces than hydrocarbons, weaker than alcohols

• slightly soluble in water with lower molecular weight

• not soluble if 5 or more carbon atoms

Dehydration of Alcohols

• requires a catalyst- H+ and heat

• elimination of H and OH from adjacent carbon atoms

• primary form an alkene and water

• secondary form two possible alkenes, take hydrogen from carbon with less (major product has fewer hydrogen atoms on double bond)

Oxidation of Alcohols

• [O]

• increases number of carbon oxygen bonds - add oxygen or remove hydrogens

• primary alcohols are oxidized to produce aldehyde then can react again to form a carboxylic acid (carbonyl bonded to OH)

• secondary alcohols are oxidized to produce a ketone

• tertiary alcohols do not oxidize because there are no hydrogen atoms on the carbon bonded to the OH group

Oxidation of Thiols

• an H atom is lost from each of the -SH groups

• product is disulfide

• uses 2 thiols to produce product

Reduction of Thiols

• [H]

• an H atom is added to each sulfur to create -SH groups

• disulfides will reduce to thiols

• 2 products

Thiols

-SH group

Ethers

R-O-R

Aldehyde

carbonyl attached to R and H

Ketone

carbonyl attached to R and R

Carboxylic Acid

carbonyl attached to R and -OH

• COOH

Ester

carbonyl attached to R and -OR

• RCOOR

Boiling Point Ketones

• experience dispersion and dipole dipole, but no hydrogen bonding within ketones

• higher boiling point than aldehydes, lower than alcohols

• boiling point increases as carbons increase

Boiling Point Aldehydes

• experience dispersion and dipole dipole, but no hydrogen bonding within aldehydes

• lower bp than ketones, higher than alkanes

Solubility Ketones and Aldehydes

• Form hydrogen bonds with water molecules between the carbonyl oxygen and hydrogen atoms on water molecules 

• Are very soluble when they have four or fewer carbons 

• More carbons/longer carbon chains are nonpolar, diminishing solubility effect of the polar carbonyl group 

Hemiacetal

OH and OR attached to same carbon atom

Acetal

OR and OR attached to same carbon atom

Oxidation Aldehydes

• aldehydes oxidize to carboxylic acids- carbonyl attached to R and OH

Chromic Acid (Jones Test)

• K2CrO4/ H2SO4

• oxidizes alcohols and aldehydes

Benedict’s Test

• Cu(OH)2 / sodium citrate

• oxidizes aldehydes

• add O to H on carbonyl

Tollens’ Test

• Ag2O / NH4OH

• oxidizes aldehydes only

• add oxygen to H on carbonyl

Reduction of Aldehydes and Ketones

• add H2

• aldehydes reduce to primary alcohols

• ketones reduce to secondary alcohols

• reduced by H2 or NaBH4 and a metal catalyst (Ni, Pt, or Pd)

• decreases number of C-O bonds

Aldehyde and Ketone Reaction

• react with one mole of alcohol and acid to form a hemiacetal

Hemiacetal Reaction

• will react with 1 mole of alcohol and acid to form an acetal

Cyclic Hemiacetal Formation

• hydroxyl group is looped to carbonyl group

• bonds break to form cyclic, H goes goes to double-bonded O

Hydrolysis Reaction of Hemiacetals and Acetals

• Reverse of formation of hemiacetals/acetals 

• Requires water and acid (H2SO4) 

Aldehyde Common Name

• aldehydes of 1-4 carbons

• 1- formaldehyde

• 2- acetaldehyde

• 3- propionaldehyde

• 4- butyraldehyde

Ketones Common Name

• alkyl groups bonded to carbonyl group are turned into substituents and are listed in alphabetical order before ketone with spaces

• ex: 2-propanone - > dimethyl ketone

• ex: 2-butanone → ethyl methyl ketone

Phenols Common Name

• ortho (o)- substituents on 1 and 2

• meta (m)- substituents on 1 and 3

• para (p)- substituents on 1 and 4

Ethers Common Name

• names of each alkyl or aromatic group attached to the oxygen atom are written in alphabetical order then followed by ether

Ethers IUPAC

• An alkoxy group of a smaller alkyl group and the oxygen atom 

• Add the alkane name of the longer carbon chain 

• Add the locator number of where the alkoxy group is attached to the longer group 

isopropyl

CH3-CH-CH3 (bonds to central carbon at middle C)

propyl

CH3-CH2-CH2- (bonds to central carbon at end)

butyl

CH3-CH2-CH2-CH2- (bonds to central carbon at end)

isobutyl

sec-butyl

CH3- CH- CH2- CH3 (bonds to central carbon on second C)

tert-butyl

R Designation

• lowest priority on vertical

  • clockwise- R

• lowest priority on horizontal

  • counterclockwise- R

S Designation

• lowest priority on vertical

  • counterclockwise- S

• lowest priority on horizontal

  • clockwise- S

Haworth Structures

1. Turn Fischer projection clockwise 90 degrees

2. Fold to make a hexagon. OH on carbon 5 bonds with carbonyl 1. CH2OH becomes 5.

3. Join oxygen on last chiral center to carbonyl carbon. remove H from OH and add H to carbonyl. C = O becomes C- O

Anomeric Center

carbon formerly in the carbonyl, but is now bound to the ring O atom and a hydroxyl

alpha anomer

OH is below ring

beta anomer

OH is above ring

Mutarotation

a-anomer and b-anomer convert when in solution.

• cyclic structure opens + closes

• A-D-glucose → B-D-glucose

Oxidation of Monosaccharides

• requires Cu²

• Cu² is reduced to Cu+

• -ose to -onic acid

• add O to H

• forms a carboxylic acid

Oxidation of Ketoses

• ketone carbonyl group has to form an aldose and then be oxidized to a carboxylic acid using Benedict’s regent

• requires Cu²+ and OH

• forms carboxylic acid and Cu2O

Reduction of Monosaccharides: Aldoses

• requires H₂/Pd

• carbonyl group of an aldose is reduced to a primary alcohol

• produces a sugar alcohol- alditols

• -ose to -itol

Reduction of Monosaccharides: Ketoses

• carbonyl group of ketose is reduced to a secondary alcohol

• uses H2/Pd

• two possible products (OH can go on either side)

Maltose

• made of glucose

Sucrose

Made of glucose and fructose

Lactose

Made of galactose and glucose

Glycosidic Linkage

• covalent bond joining two monosaccharides

• between one anomeric carbon center of the sugar at the left and of hydroxyl group of sugar at the right

• b if o is above, a if o is below

Reducing Sugar

contain a hemiacetal RO-C-OH

Amylose

• a (1→ 4) glycosidic bonds

• minor component of starch

• unbranched with helical shape due to hydrogen bonding

Amylopectin

• a (1→ 6) glycosidic bonds

• major component of starch

• branched polysaccharide

• branching occurs every 30 glucose units

Cellulose

• b (1→ 4) glycosidic bonds

• main component in wood, paper, and cotton

• unbranched D-glucose with a strong layered shape

• gives strength to plants due to hydrogen bonding

• humans cannot digest

Carboxylic Acid

• COOH

Naming Carboxylic Acids: IUPAC

• -e is replaced with -oic acid

• use the same naming rules as usual

• carboxylic acid does not require a locator number

Preparation of Carboxylic Acids

• can be prepared through oxidation from primary alcohols or aldehydes

Carboxylic Acid Boiling Point

• strongly polar because they have two polar groups, higher boiling point than alcohols

Carboxylic Acid Dimers

• carboxylic acids can form dimers, hydrogen bond with itself

• two hydrogen bonds between carboxyl groups

Carboxylic Acid Solubility

• can hydrogen bond with water

• very soluble with 1-5 carbons

Carboxylic Acid Dissociation

• carboxylic acids are weak acids

• they dissociate in water to form carboxylate ions

• lose H off carboyxlic acid, add to water

• negative charge on ion, positive on water

Carboxylic Acid Neutralization

• carboxylic acid reacted to a strong base, NaOH or KOH

• lose H from carboxylic acid, base loses OH

• forms water

• negative charge on salt + cation

Naming metal salts

name of metal cation + parent chain + ate

Esters

• contain a carbonyl group bound to an -OR group

• RCOOR

Esterification

• ester formation

• carboxylic acid + alcohol

• requires H+ and heat

• carboxylic acid loses OH, alcohol loses H

• forms water

Ester Acid Hydrolysis

• reverse of esterification

• adds water

• requires acid catalyst + heat

• produces an alcohol and a carboxylic acid

Ester Base Hydrolysis

• reaction of ester with a strong base + heat

• produces a carboxylate salt (ionic) + alcohol

• salt has a negative charge on O and positive on Na

Naming Esters

• -e to -oate

• parent chain includes carbonyl

• carbons on other side of O are treated as a substituent

Esters Boiling Point

• higher than alkanes and ethers'

• lower than alcohols and carboxylic acids of similar mass

Esters Solubility

soluble in water if they have 2-5 carbon atoms

Lipids

contain fatty acids or a steroid nucleus

Fatty Acids

• long unbranched carbon chains with a carboxylic acid group at the end

saturated fatty acid

do not contain carbon carbon double bonds

unsaturated fatty acid

contain carbon carbon double bonds

Myristic Acid

14 carbon atoms, 0 double bonds

Palmitic Acid

16 carbon atoms, 0 double bonds

Stearic acid

18 carbon atoms, 0 double bonds

Oleic acid

18 carbon atoms, 1 double bond

Linoleic acid

18 carbon atoms, 2 double bonds

Linolenic acid

18 carbon atoms, 3 double bonds

Arachidonic acid

20 carbon atoms, 4 double bonds

Saturated fatty acids properties

• C-C single bonds, fit close together in regular pattern

• strong dispersion forces

• higher boiling point/melting point

• solids

Cis double bonds in unsaturated fatty acids

• give the molecule an irregular shape, resulting in fewer interactions between molecules

• lower boiling/melting point compared to saturated fatty acids

Properties of Fatty acids

• as size of molecule increases, melting point increases

• cis bond decreases melting point

Delta System

• number starting at carbonyl carbon, use locator number and triangle for double bonds

Omega System

• start numbering with C farthest from carbonyl

• use locator number and w to indicate double bond

Waxes

esters of saturated fatty acids and long chain alcohols

ester bond connects fatty acid and alcohol