Chemical processes, carbohydrate

Tetrose (Section 25 3) A carbohydrate with four carbon atoms Thermochemistry (Section 2 18) The study of heat changes that accompany chemical processes Thermodynamically controlled reaction (Section 10 10) Re action in which the reaction conditions permit two or more products to equilibrate giving a predominance of the most stable product... 

Electron-transfer reactions occur all around us. Objects made of iron become coated with mst when they are exposed to moist air. Animals obtain energy from the reaction of carbohydrates with oxygen to form carbon dioxide and water. Turning on a flashlight generates a current of electricity from a chemical reaction in the batteries. In an aluminum refinery, huge quantities of electricity drive the conversion of aluminum oxide into aluminum metal. These different chemical processes share one common feature Each is an oxidation-reduction reaction, commonly called a redox reaction, in which electrons are transferred from one chemical species to another. 

Alternatively, an entirely new downstream process and product chain, using renewable raw materials, can be conceived (the biorefinery ). The chemistry will be more focused on that of oxohydrocarbons (particularly carbohydrates) rather than hydrocarbons. Understanding the materials chemistry of biomass and related products would need to be enhanced. However, work has already been undertaken to identify the top sugar-derived intermediates (Figure 1.9) on which down-stream chemical processing might be derived. 

V. Carbohydrate Transformation in Chemical Processes, Including Humus... 

In some chemical processes, including natural humus formation, non-enzymic carbohydrate transformation, in aqueous media, into noncarbohydrate products is important. 

Photosynthesis, the process by which plants and other organisms use solar energy to convert water and carbon dioxide into complex energy-rich chemicals, the carbohydrates and oxygen, is essential to life on this planet. We now have a greater understanding of how this process works and hence we should be able to construct processes that mimic nature to our advantage. 

In the past four chapters, we have learned something about fats, carbohydrates, and proteins their structures and how these are determined, and the kind of reactions they undergo in the test tube. These, we said, are biomolecules they are participants in the chemical process we call life. But just what do they ciol What reactions do they undergo, not in the test tube, but in a living organism ... 

The use of renewable resources as substrates in chemical processes has recently been reviewed [1]. There are two major topics of current research (1) oleochem-ical reactions, and (2) chemical transformation of carbohydrates. Nevertheless, the chemical possibilities of renewable resources as substrates - using homogeneous catalysis - are still very far from being fully exploited. 

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