The document summarizes the Gattermann reaction, which is a chemical reaction that formylates aromatic compounds. Specifically, it involves treating benzene or its derivatives with hydrogen cyanide and hydrogen chloride in the presence of aluminum chloride. This leads to the formation of an electrophile that attacks the benzene ring. After hydrolysis, it produces benzaldehyde or substituted benzaldehydes. The reaction is named after German chemist Ludwig Gattermann and provides a method for obtaining chlorobenzene or bromobenzene.

1. GATTERMANN REACTION
NAME: KLIFFORD SANJAY
D.NO: 18PCH106
DEPARTMENT OF CHEMISTRY
ST JOSEPH COLLEGE (AUTONOMOUS)
TRICHY-02

2. GATTERMANN REACTION
INTRODUCTION:
THE GATTERMANN REACTION IS ALSO KNOWN AS GATTERMANN
FORMYLATION REACTION.
IT IS A CHEMICAL REACTION IN WHICH THE AROMATIC COMPOUNDS
ARE FORMYLATED BY A MIXTURE OF HYDROGEN CYANIDE(HCN)
AND HYDROGEN CHLORIDE(HCl) IN THE PRESENCE OF LEWIS ACID
CATALYST SUCH AS AlCl3.
IT IS NAMED AFTER GERMAN CHEMIST LUDWIG GATTERMANN.
IT IS SIMILAR TO FRIEDAL CRAFTS REACTION.

3. LUDWIG GATTERMANN

4. REACTION
WHEN BENZENE OR ITS DERIVATIVE IS TREATED WITH HCl AND HCN IN
THE PRESENCE OF LEWIS ACID CATALYST AlCl3, FOLLOWED BY
HYDROLYSIS IT GIVES BENZALDEHYDE OR SUBSTITUTED
BENZALDEHYDE.

5. MECHANISM
STEP 1: FORMATION OF FORMIMINO CHLORIDE

6. • STEP 2: FORMATION OF ELECTROPHILE

7. STEP 3: ATTACK OF ELECTROPHILE ON BENZENE RING

8. STEP 4: HYDROLYSIS OF BENZALDIMINE

9. APPLICATION
GATTERMANN REACTION IS USED FOR OBTAINING CHLOROBENZENE
OR BROMOBENZENE FROM BENZENE DIAZONIUM CHLORIDE BY
TREATING IT WITH Cu/HBr RESPECTIVELY.