AKUNGBA AKOKO, ONDO STATE.FACULTY OF EDUCATION

DEPT: SCIENCE & TECHNICAL EDUCATION

UNIT: INTEGRATED SCIENCE EDUCATION

LEVEL: 300

COURSE TITLE: CARBON COMPOUND II

COURSE CODE: ISE 308

GROUP II

QUESTION

Chemistry of Carbonyl Compound (Alkanal and Alkanone) 

NAMES MATRIC NO

ADESUYI GRACE ADEOLA 090224001

AJIBISE FEDELIX TOMIDE 090224005

AJIMUDA ABOSEDE CHRISTANA 090224006

KOLAWOLE REMILEKUN THERESA 090224018

  Lecturer-in-Charge

Dr. K.O. Oloruntegbe

CARBONYL GROUP OR COMPOUNDSALKANALS AND ALKANONESlkanal (Aldehydes) and Alkannone (Ketones) both contains the

carbonyl group. And this carbonyl compound is produced by which the carbon atom reacts with a double bond of oxygen atom.

OC Carbonyl group

Alkanal have at least one hydrogen atom bonded to the carbon atom as well as the oxygen.

OR C H where R= H alkyl

groupAlkanal therefore has two organic radicals attached to the carbon atom which may be the same or differ.

O R C Rl where R and Rl

are the two organic radicals.

You can tell whether a substance is an alkanal or ketone by looking at its formula. The alkanal have a common formula RCHO while,(2) The alkanone has its own formula as RR1COAliphatic alkanals are named after the corresponding alkane by replacing the ending “-e” with “-al”, e.g methanal (HCHO, ethanal (CH3CHO),e.t.c.

Aromatic alkanals are named hydrocarbon carbaldehyde e.g phenylmethanal (benzene carbaldehyde) C6H6CHO.

Aliphatic alkanones are named BY Changing the corresponding alkane ending with “-e” to “-one” e.g propannone (CH3COCH2). Pentane 2 –one (CH3 – CH2 – COCH3). The two common aromatic ketones are phenylethanone C6H5COCH3 and diphenylmethanone, (C6H5C0C6H5).

Name Other name Formula State At RoomTemp.(g) BoilingPoint(0C) Solubility in waterMethanal Formaldehyde HCHO 254 SolubleEthanal Acetaldehyde CH3CHO 1 294 Infinite

Propanal Propionaldehyde CH3CH2CHO 1 321 Soluble

Propanone Acetone CH3C0CH3 1 329 Infinite

Butanone Methylethyl Ketone CH3C0CH2CH3 1 353 Very soluble

Pentan-3-one CH3CH2COCH2CH3 1 375 Very soluble

Benzal-dhyde HO 1 451 Slight solublePhenyle-thanone Acetophenone C0CH3 1 475 Insoluble

PHYSICAL PROPERTIESAlkanals and Alkanones possess the following characteristics:

1. They are often sweet smelling, volatile and liquid in nature.

2. Ethanal has a sweet characteristic which may be detected near a rotten fruit (e.g you might try leaving an apple to rot, eventually you will smell ethanol coming from it).

3. They are polar and are therefore soluble in water i.e the ones with short carbon chains (1c to 5c).

4. The hydrogen bonding in alkanals and alkanone account for their comparatively high boiling point with rest molecular mass.

Question: Why are carbonyl compound polar?

Answer : They are polar owning to the electronegative oxygen drawing electron density towards itself.

METHOD OF PREPARING ALKANAL AND ALKANONE Oxidation of Alcohol: This is the simplest method, and it can be achieved by using acidified solution of sodium dichromate (v) or by passing the alcohol vapor over hot copper powder. Primary alcohols are oxidized to alkanals and secondary alcohols to alkanone. E.g.

H H(a) R – C - OH + (0) R – C = O + H2O

H from oxidizing alkanal agent

Primary alkanal E.g.

H HCH3 – C – OH + (O) – CH3 – C = O + H2O

H Ethanal ethanal

R1 R1

b) R – C – OH + (O) R - C = O + H2O

from oxidizing alkanone agent

Secondary alkanolE.g

CH3 CH3

CH3 – C - OH + (O) CH3 – C = O + H2O

H propanone2. Ozonolysis: This can be used to convert an alkene into alkanal or

alkanones. It swaps to carbonyl groups for the carbon-carbon double bond in an alkene.a) H H H H

C = C C = O + O = C H H H H Ethene methanal methal

 

b) CH3 H CH3 H

C = C C = O + O = C H H H H But-1-ene propanal methanal

(3) CH3 H CH3 H

C = C C = O + O = C

CH3 H CH3 H

Propanone methal

REACTIONThe alkanal and alkanones undergoes addition reaction and the following reaction are

the addition reaction.(a) Hydrogen Sulphite Addition (HS03

-): This will add to both alkanal and alkanones. The net results of the addition is shown in this reaction.CH3COCH3 + HSO3

- CH3C(OH)(SO3-)CH3

O OH

C + HS03- C

CH3 CH3 CH3

CH3 SO3

Alchohol addition: Alkanals, but not alkanones, will give addition reactions with alcohols provided all the reagent are dry, and that Hydrochloric acid (HCL) is used to catalyse the reaction. The most common example of this type of addition is ethanol additing to ethanal.

dryCH3CHO + 2C2 H5 OH HCl CH3CH (OC2 H5)2 + H2O

1, 1 – diethoxyethane O twice

CH3 – C + 2C2 H5OH CH3 – C – OC2 H5 + H2O

H OC2 H5

The product, 1, 1 – diethoxyethane, was once known as Acetal. It is a type of other.

(3) Cyanide Reaction: (CN )This particular reaction is useful because it provides us a pathway for making mixed alcohol and acids. If a nitrile is hydrolysed, it is converted into “carboxylic acid”. Thus, we can carry out the changes.

H+

CH3CHO CH3 CH (OH)CN CH3CH (OH) COOH

Ethanal 2– hydroxyl propane- 2-hydroxyl propanoic Nitrile acid

O OH OH CH3 – C CN, H+ CH3 C CH3 C

H H CN COOH

2- Hydroxyl propanoic acid is also known as LACTIC ACID. It was been widely studied because it is one of the substance made when milk goes sour. The acid is formed by the action of a micro-organisms, Bacillus acidi lactici, on sugar. In the early 1900’s large amount of the bacteria were isolated and used to prepare lactic on an industry scale. The acid was used in dyeing and also in leather industry.

It was been widely studied because it is one of the substance made when milk goes sour. The acid is formed by the action of a micro-organisms, Bacillus acidi lactici, on sugar. In the early 1900’s large amount of the bacteria were isolated and used to prepare lactic on an industry scale.The acid was used in dyeing and also in leather industry.

(4) REDUCTION: Alkanals are reduced to primary alkanols while alkanones are reduced to secondary alkanols by powerful reducing agents like lithium Tetrahydrido aluminate (III) {LiAlh4} and sodium Tetrahydriobotrate (III) (NaBH4

-).

HCH3 – C = 0 + 2(H) CH3 CH2 - OH

Ethanal ethanol

CH3 CH3

CH3 – C = O + H CH3 – C – OH

Propanone H Propan 2- OC

(5) Oxidation: Alkanals are readily oxidized to alkanoic acids in the presence of strong oxidizing agent like acidified potassium tetraoxomanganate (VII) and acidified potassium heptaoxodi chromate (v) H OCH3 – C = O + (O) CH3 C

OHWhile alkanones are more different to oxidize because there is no oxizidable hydrogen attached to the carbonyl group and it involves breaking the C-C and C-H bonds. Only strong oxidizing agents like hot concentrated trioxonitrate (vi) acid and acidified KMno4 can oxidize alkanones. In the process, the Alkanones molecule is broken up into two acids.CH3COCH3 (O) CH3COOH + CO2 + H2O

CH3CH2CH2COCH3 (0) CH2CH2 COOH + CH3 COOH

USESAlkanals such as:

(a)Methanal are used in solution with water, sold as formalin a disinfectant (formaldehyde) in the preservation of same biological specimens.

(b) Methanal is also used as an imperative material in the production of plastic such as bakelite.

(c) Ethanal is used in the manufacture of ethanoic acid and its derivatives e.g ethanoic anhydride.

(d) More complex aldehydes are found in perfumes and flavourings. Alkanones such as

(e) Propanone (acetone) are used as a solvent. This is a more important used than you might think. E.g many artificial fibres are manufacture

(f) Some alkanones can be used as intermediate in the manufacture of other chemicals, e.g cyclohexanone is used in one stage of nylon manufacture.