Sciencemadness Discussion Board

Disability and Chemistry

Chemorg42 - 8-6-2020 at 17:48

Wasn't sure where to post this, mods, feel free to move this thread if there is a better sub-forum for it.
Ever since I joined this forum, I have been debating with myself whether to divulge this information. However, I now have a request which makes the sharing of said information essential. So here it goes.
Since birth, I have had almost no vision. Medically, I am visually impaired, however, for all intents and purposes, in common speech, I am blind. I generally have someone I trust help me in the lab.
Now, on to the request. I have quite a good grounding in chemical theory (both inorganic and basic organic), but my lack of vision has made it more difficult to understand certain concepts. In particular, I have been struggling for the last few weeks to understand several common organic reaction mechanisms, such as Fisher Esterification, as well as some other common mechanisms.
I have read articles, I have watched videos, but without exception, all rely on visual diagrams to explain the mechanism. Sure, some have descriptions to go along with each image, but these are always incomplete and rely on the images to make sense. I have a solid understanding of the various components of mechanisms (oxidation states, Lewis acids and bases, nucleophiles and electrophiles, protonation and deprotonation, etc), its just that I have know resources that accurately and completely explain these mechanisms.
So, here is my request. Are any of you both willing and qualified (or know someone who is willing and qualified) to explain these mechanisms to me (preferably over the phone or some other audio medium?)
I feel like a jerk for even asking, but I really don't know of any other options. If anyone has any suggestions on what to try, please share them.

arkoma - 8-6-2020 at 22:13

Do you have a "stick and ball" molecular model kit? The "atoms" are different sizes so you could tell what was where by touch and build a model of acetic acid and one of ethanol and combine them and feel where the water molecule comes from.

A thought.

Chemorg42 - 8-6-2020 at 22:38

Thank you for the suggestion, however, visualization is not the issue. I can visualize the molecules structures very well, it is understanding the electron movements. The only way a kit such as this would be useful would be if I had someone who could explain the mechanism, step by step, or a (very) detailed article on the subject.
Sincere thanks for this post, as well as your thoughtful message.

Bromolone - 8-6-2020 at 23:45

Hello Chemorg42.

Reaction mechanisms can be grasped well via text rather than images (Solomons' Organic Chemistry often beautifully writes the reaction mechanics below diagrams in several commonly encountered organic reactions). Translating the text into 'reaction diagrams' (electron transfers, rearrangements, and the like) is a skill that might require some practice, but as you hold a good grip on the basics, this might become easier.

I understand the difficulty of comprehending the mechanism of pericyclic reactions without visual aids, and I couldn't find suitable textual descriptions that explain which bond goes where and why in a pericyclic reaction.
But if you ask for a specific reaction (such as chlorinations with thionyl chloride), explanations are easy to provide.

Feel free to ask on the thread or via message.

The Fischer esterification is easily explained verbally.
(From Wikipedia):
Quote:


1.Proton transfer from acid catalyst to carbonyl oxygen increases electrophilicity of carbonyl carbon.
2. The carbonyl carbon is then attacked by the nucleophilic oxygen atom of the alcohol
3. Proton transfer from the oxonium ion to a second molecule of the alcohol gives an activated complex
4. Protonation of one of the hydroxyl groups of the activated complex gives a new oxonium ion.
5. Loss of water from this oxonium ion and subsequent deprotonation gives the ester.



A link that might be of some help:

https://www.nfb.org/sites/www.nfb.org/files/images/nfb/publi...

Also, please take appropriate safety measures while working in the lab. :)

[Edited on 9-6-2020 by Bromolone]

Chemorg42 - 9-6-2020 at 06:09

Thanks, excellent description of the mechanism.

ThoughtsIControl - 9-6-2020 at 21:42

Quote: Originally posted by Chemorg42  
Thank you for the suggestion, however, visualization is not the issue. I can visualize the molecules structures very well, it is understanding the electron movements. The only way a kit such as this would be useful would be if I had someone who could explain the mechanism, step by step, or a (very) detailed article on the subject.
Sincere thanks for this post, as well as your thoughtful message.


I am currently teaching myself organic chemistry via youtube. I was struggling with electron movements myself so let me tell you a revelation I had along the way that may seem obvious to some but wasn't to me until I paid closer attention. So, let me give it a shot to explain the best I can.

Each element has a state at which it is most stable. Nitrogen, for example, really likes to have three covalent bonds and a lone pair of electrons in order for Nitrogen to be in the most stable state. Perhaps I have ammonium (Nitrogen with 4 covalent bonds to Hydrogens). The ammonium will have a positive charge, because it has more protons than electrons. It is going to want to be more stable and trade that hydrogen for a lone pair of electrons. So if the ammonium reacts with a carbon chain of some sort, then it will react in a way that arranges the products in the most stable way. The process of achieving stability with charge is what a lot of organic chemistry is about.

Hope this helps

Chemorg42 - 10-6-2020 at 06:51

@Thoughts, thanks for the suggestion.
I have never thought about it in quite that way. At first, I simply thought of ionic and covalent bonds, sharing or donating single electrons. Now, I think of molecules donating single or pares of electrons to bonds of differing polarities.
As to reaction products, I have never thought of the stable configuration idea. I always simply follow the logical path and see where I end up. In fisher esterification, for example, of course the acidic proton of the catalyst will attack the carbonyl oxygen, it is the most nucleophilic part of either of the molecules (very polar double bond with carbon, resulting in an extremely low oxidation state.)