Hydrogenation of Alkenes

How can you convert an unsaturated hydrocarbon such as an alkene, into a saturated hydrocarbon (an alkane)?
With the magic of chemistry (a catalyst), you can add hydrogen across the double bond in an alkene!
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Classification of Organic Reactions

Organic reactions are reactions in which the reactants and products are carbon-containing compounds, or organic compounds.
The chemical reactions that organic compounds take part in can be classified as:

• substitution reactions
• addition reactions
• elimination reactions
• oxidation reactions
• reduction reactions
• polymerisation reactions
• rearrangement reactions

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Producing Organic Compounds from Bip-oils

Many chemical feedstocks such as ethene and propene, the building blocks of many plastics, as well as aromatic compounds such as benzene and toluene used in dyes and plastics, are currently produced from petroleum.
University of Massachusetts Amherst scientists have reported that they have developed a way to produce these feedstocks from pyrolytic bio-oils, the cheapest liquid fuels available today derived from biomass. These pyrolytic bio-oils can be made from non-food agricultural crops and woody biomass.
The two-step, integrated catalytic approach starts with a "tunable", variable-reaction hydrogenation stage followed by a second, zeolite catalytic step. The zeolite catalyst has the proper pore structure and active sites to convert biomass-based molecules into aromatic hydrocarbons and alkenes.

Journal Reference
Tushar P. Vispute, Huiyan Zhang, Aimaro Sanna, Rui Xiao, and George W. Huber. Renewable Chemical Commodity Feedstocks from Integrated Catalytic Processing of Pyrolysis Oils. Science, 26 November 2010: 1222-1227 DOI: 10.1126/science.1194218

Further Reading
Nomenclature of Carbon Compounds
Naming Simple Alkenes
Ethene: properties, production and uses
Polythene: properties, production and uses
Polymers and Polymerization

Study Questions

1. Give the molecular formula and structural formula for ethene.
2. Give the molecular formula and structural formula for propene.
3. Give the molecular formula and structural formula for benzene.
4. Give the molecular formula and structural formula for toluene.
5. What is meant when an organic chemist refers to hydrogenation?
6. What is meant by the term pyrolytic?
   
7. Write an equation for the hydrogenation of ethene.
8. Write an equation for the hydrogenation of propene.
9. Why is benzene classed as an aromatic compound and not as an alkene?