Producing Ethanol: The Role of Lewis Structures in Chemical Bonding

  • Thread starter bjoyful
  • Start date
  • Tags
    Ethanol
In summary, producing ethanol for use as a gasoline additive can be achieved through the reaction of water vapor with ethylene, resulting in the formation of ethanol. This reaction is known as an electrophilic addition reaction, where the pi bond of the C=C and the O-H bond of water are broken, forming a carbocation and ultimately leading to the formation of ethanol. Another method for producing ethanol is through the fermentation of glucose by yeast, but this method only yields about 15% ethanol and requires anaerobic conditions. Lastly, ethene and water can also form ethanol under specific conditions of high temperature, the use of H₃PO₄ as a catalyst, and pressure of 65 atm.
  • #1
bjoyful
61
0
producing ethanol...

Homework Statement


One way to produce ethanol for use as a gasoline additive is the reaction of water vapor with ethylene: H2C=CH2 + H2O ----> CH2CH2OH Rewrite this equation on a piece of paper using Lewis structures, and use those structures to answer the following question: Was it necessary to break all of the chemical bonds in the reactants in order to form the product, ethanol? Explain your answer.

Homework Equations



The Attempt at a Solution



I rewote the equation on a piece of paper with the Lewis structures H2C= H-C-H, CH2= H-C-H, H2O= H-O-H, CH2= H-C-H, CH2= H-C-H, OH=O-H. I also wrote for ethanol: H-C=O=C-H (with single bonds of H coming off of the C on both top and bottom, due to format limitations, I can't right it..:( Is this right? Was it necessary to break all of the chemical bonds to form reactants?
Thanks!
 
Physics news on Phys.org
  • #2
errmm no you don't have to break all the bonds...

do you know the mechanism for this reaction?
 
  • #3
I am not sure about the mechanism for this reaction...I am totally new at this chemistry stuff! Thanks for your help:)
 
  • #4
this is called electrophilic addition reaction. basically electrophiles are species which are attracted by negatively charged species. so in ethene there is a pi bond in the C=C.

now, in water, there is oxygen atom which is very electronegative. it tends to pull the shared pair of electron across the O - H bond towards itself. hence, it gets a partial negative charge. the hydrogen consequently gets a partial positive charge. this is why water is polar.

when water molecules approach the pi bond, the pi electrons further repel the shared pair of electron in the O - H bond causing heterolysis. H+ and OH- are formed.

the H+ is attracted towards the pi bond(consisting of electrons). the pi electrons (in the pi bond) forms a covalent bond with the H+.

now, the ethene molecule becomes CH3C(+)H2. this is known as a carbocation. the carbon has a positive charge.

remember the OH- ion? it then forms a covalent bond with the carbocation(C+). ethanol is finally formed.

this is the simplest example of electrophilic addition reaction.

so, the only bonds broken are the pi bond of the C=C (not the sigma bond) and O - H from water.i hope this is your level of chemistry...
 
  • #5
So I don't have to break all the bonds to form ethanol, just the C=C and the O-H?
 
  • #6
another much more simple approach was to compare the lewis structures of both ethene and ethanol, to see which bonds have changed. it would be obvious that the C = C was broken as well as H - OH bond.

and i guess this was the approach required... sorry if i complicated things...
 
  • #7
in short yeah...
 
  • #8
No I think I am the one complicating things! I see what you are saying. I am taking this chemistry course online, and i am not sure that was the greatest idea! Oh well, thank God for people like you...
 
  • #9
anytime... good luck
 
  • #10
I think Glucose + Yeast also can become Ethanol
 
  • #11
yeah, but in the absence of oxygen (anaerobic)
however only about 15% ethanol will be obtained...
 
  • #12


Besides that, I noticed that Ethene + Water also can form Ethanol but 3 requirements is needed.
1. temperature 300°C
2. use H₃PO₄ as catalyst
3. pressure 65 atm
 

FAQ: Producing Ethanol: The Role of Lewis Structures in Chemical Bonding

What is ethanol and how is it produced?

Ethanol is a type of alcohol that is commonly used as a fuel source. It is produced through a process called fermentation, where yeast breaks down sugars in plants such as corn or sugarcane.

What are Lewis structures and why are they important in chemical bonding?

Lewis structures are diagrams that show the bonding between atoms and the placement of electrons within a molecule. They are important in chemical bonding because they help us understand how atoms bond together to form molecules and predict their properties.

How do Lewis structures play a role in producing ethanol?

In the production of ethanol, Lewis structures are used to represent the chemical bonds and electron placement in the molecules involved. This helps scientists and engineers understand the reactions and processes involved in producing ethanol.

Can Lewis structures be used to determine the efficiency of ethanol production?

While Lewis structures are important in understanding the chemical reactions involved in producing ethanol, they cannot be used to directly determine the efficiency of the production process. Other factors such as the type of feedstock and production methods also play a role in efficiency.

Are there any environmental concerns associated with producing ethanol using Lewis structures?

Lewis structures themselves do not pose any environmental concerns in the production of ethanol. However, the use of ethanol as a fuel source has raised concerns about its impact on food prices and land use.

Similar threads

Question about Calculating Bond Energies
Replies
4
Views
2K
Chemistry How do we know ##BF_3## has Lewis structure but ##Al_2S_3## does not?
Replies
1
Views
1K
Bond Dissociation Energy Problem
Replies
2
Views
6K
Lewis Reaction Questions (Organic Chemistry)
Replies
2
Views
5K
Chemistry: Heat of Sublimation and Hydrogem Bonds Problem
Replies
5
Views
2K
Lewis structure and thermochemistry problems
Replies
3
Views
3K
Heat of Formation: Solve Ethylene C2H4 Combustion
Replies
3
Views
14K
Structure of Molecule Based on Spectra Analysis
Replies
1
Views
2K
Hydrogen bond between tetrafluoromethane and water
Replies
1
Views
3K
Chemistry Determining the positive and negative poles of a molecule
Replies
6
Views
5K

Hot Threads

Recent Insights

Back
Top