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7th principle of green chemistry Use of renewable feedstocks: A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable. A feedstock is considered green if it satisfies the following conditions: • It should impose least demands on the earth's resources. • It‘s acquisition and refining should be safe. • It should be non-hazardous and relatively safe. • If possible, feedstock should always be renewable for example feedstocks from biomass that can be grown repeatedly should be given preference to depletable petroleum feedstocks. • Reusing of waste from bio-industries, if possible, as raw material or feedstock. Various examples are listed below: 1. Chitan, a waste from of seafood industry can be transformed into Chitosan by Deacetylation that has many applications as in water purification, biomedical and in other industries. It would definitely replace the petroleum feedstocks. 2. Lignin, a waste from paper and pulp industry, is used as feedstock for manufacture of Annelyn venelin DMSO Continued…. 3. Lipids and hydrocarbon terpenes are the oils, greases and waxes which have same properties as that of petroleum products and are used to synthesize the synthetic liquid fuels and also can be used directly as diesel fuel. 4. For chemical synthesis, the fatty acids from natural sources is advantageous because of the carboxylic acid group and the presence of reactive double bond between two carbon atoms in the carbon chain. For example oleic acid from sunflower, linolenic acid from soya bean and linseed, rinoleic acid from Castor oil etc. 5. The carbohydrates as feedstocks have advantages as they have many hydroxyl functional groups that may provide sites for the attachment of other functionalities or to initiate chemical reactions. 6. Cellulose another bio feedstock is mostly employed as plant biomass suppliants thus diminishing the need of petroleum feed stocks. Biological processes Biological processes produce a variety of biopolymers like cellulose. hemicellulose, lignin, starch, proteins, lipids, monosaccharides (glucose), disaccharides (sucrose), waxes, fats, oils, terpene hydrocarbons etc. The three main steps in acquisition of a feedstock and converting it into useful product are : 1. Source (lifetime methods and environmental impacts of extraction ) 2. Separation of desired components from the waste or byproduct matter 3. Conversion of isolated feedstock material to desired product Each of the above three steps have environmental effects and can benefit from the application of the Principles of green chemistry This Photo by Unknown Author is licensed under CC BY Conventional synthesis of Adipic acid from Cyclohexane This Photo by Unknown Author is licensed under CC BY-NC Green method for the synthesis of Adipic acid from D-Glucose
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