Chemicals Based Technologies - Gallic Acid from Myrobalan (Terminalia Chebula)

Introduction

Gallic acid, chemically known as 3,4,5- Trihydroxy benzoic acid, finds primary use as the basic intermediate for a very important anti-bacterial drug, ‘Trimethoprim’. It is also used in pharmaceutical industry as astringent and styptic agent. Gallic acid esters has been in use various industries as antioxidant, photographic developer, in tanning, in testing of free mineral acids, di-hydroxy acetone and alkaloids.

The tannins of the gallic acid type are used in the manufacture of ink. They form colourless, water soluble ferrous salts which on aerial oxidation becomes insoluble black salt. Gallic acid, with N-propyl ester, is used as an anti oxidants for fats and oils. It is used as a powerful photographic developer. The various industrial chemicals and drugs manufactured from gallic acid are summarised below :

• Pharmaceuticals - Antibacterial (Trimethoprim), Sedatives (Trimeto-zyne), Vasodilators (Hexobendine), Tranquillisers (Triacetamide, Capo-benic acid, Local anaesthetics (Tri-methobenzomide, Methophenazone, Amoproxin, Trimethoquinol),
  
• Dyestuffs - Anthrogelol, Gallocya-nine, Galloflavin, Ruffi Gallic acid.
  
• Chemical industries - Pyrogallol, Fungicide, Bigallates,
  
• Food industry - Methyl and propyl gallates.
  

Process

The tannins are esters of gallic acid and are obtained from extraction of galls. The tannins are also obtained from dried and powdered leaves of sumac shrub, tea leaves, oak bark, horse chest nut, myrobalan fruits, etc. Gallic acid is produced by saponification of tannins,

The myrobalan fruits are abundantly available in India and the process developed, and being offered, is the extraction from the myrobalan fruit pulps,

The pulp of the fruit of Terminalia Chebula (Myrobalan) is cooked with a dilute mineral acid. the aqueous extract is filtered and extracted with a organic solvent. Crude gallic acid is obtained on removal of solvent which is crystallised to get pure gallic acid.

Advantages

• Low capital investment
  
• High employment potential
  
• Maximum use of local raw materials and manpower resources
  
• Adaptable levels of sophistication
  

Plant Parameters

Raw Material (Tonne per Tonne of Product)

Utilities (Per Tonne of Product)

Plant & Machinery

For further information please contact :

National Research Development Corporation
( A Government of India Enterprise )
20-22, Zamroodhpur Community Center
Kailash Colony Extension
New Delhi 110 048. India
Tel: 91-11-26419904, 26417821, 26480767, 26432627
Fax: 011-26231877, 26460506, 26478010
Website: www.nrdcindia.com

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