Today was a busy but extremely successful days in many aspects. I started off the day searching literature and creating chemical structures on the computer while Dr. Van Horn was lecturing.
I ran my first successful TLC plate today. I used a 1:1 ratio of hexanes to ethyl acetate instead of a 6:1 ratio like in my first attempt. This seemed to be a perfect ratio because no starting material could be seen in the polymer product.
I also ran NMRs on the same starting material and polymer completely by myself! There wasn't even anyone else in the room. I was really excited; I think the NMR is my favorite thing I've used so far. The spectra could not have turned out any better! They showed a 100% conversion from monomer to polymer! 100%!!! Dr. Van Horn and I were astounded with excitement. This means we also found the perfect MARS settings for the polymerization. It was in the microwave for 2 hours at 110 degrees. These results were for the polymerization of caprolactone.
Hopefully these same techniques can be applied to my monomer tomorrow to create the polymer we have been after all month! I know my last day in Charleston sure will be an exciting one.
Wednesday, January 23, 2013
Monday, January 21, 2013
The Last Week
It's hard to believe my time in Charleston is quickly coming to an end. That means things in the lab are also wrapping up. The oxidation of my molecule on a five gram scale was finished by acid base extraction techniques.
We decided to also do the reaction on a 10 gram scale. That way the two can be combined as if the reaction was run on a 15 gram scale. This way a large polymer can hopefully be created by the end of the week.
A GPC was run on a previous sample that was run in the MARS and presented some really great results. It seems as if the perfect conditions to run the polymerizations in the MARS have been found!
I will have a busy last couple of days but I am excited to see the results from them!
We decided to also do the reaction on a 10 gram scale. That way the two can be combined as if the reaction was run on a 15 gram scale. This way a large polymer can hopefully be created by the end of the week.
A GPC was run on a previous sample that was run in the MARS and presented some really great results. It seems as if the perfect conditions to run the polymerizations in the MARS have been found!
I will have a busy last couple of days but I am excited to see the results from them!
Friday, January 18, 2013
Using the MARS
Yesterday was probably the best day I've had so far at College of Charleston. I feel like I really got a lot accomplished while learning a lot at the same time!
I ran my first polymerization today of caprolactone in the MARS (microwave accelerated reaction system). I set up the reaction by mixing caprolactone and benzyl alcohol in a 100:1 ratio and then adding .5 equivalent of Sn(Oct)2 and 5 mL of toluene. Then, the solution was simply placed in the MARS for 30 minutes and 110 degrees Celsius. The solution was removed and a sample was taken and placed under vacuum to remove the toluene. I then ran that sample on the NMR to calculate the percent conversion on monomer into polymer (I ran the NMR all by myself! I was really excited!). This process was repeated after 60 minutes and 90 minutes. As expected, more polymer was created from monomer the longer it was left in the microwave. After 90 minutes, there was almost a 50% conversion!
After this, I finally got to start to work with the chemical we've been waiting for to arrive! I started the Baeyer Villager oxidation of 2-methylcyclohexanone. In basically the same steps as my first Baeyer Villager oxidation, I massed out 2-methylcyclohexanone and mCPBA. The 2-methylcyclohexanone was mixed with dichloromethane and the mCPBA was added scoop wise to the solution. One major difference I noticed was that the solution did not get frothy at all when the mCPBA was added (very different than the first time). This makes me think we may get different results, but that's what we're looking for in this research project!
Today I am going to continue the oxidation, so we'll see how things go!
I ran my first polymerization today of caprolactone in the MARS (microwave accelerated reaction system). I set up the reaction by mixing caprolactone and benzyl alcohol in a 100:1 ratio and then adding .5 equivalent of Sn(Oct)2 and 5 mL of toluene. Then, the solution was simply placed in the MARS for 30 minutes and 110 degrees Celsius. The solution was removed and a sample was taken and placed under vacuum to remove the toluene. I then ran that sample on the NMR to calculate the percent conversion on monomer into polymer (I ran the NMR all by myself! I was really excited!). This process was repeated after 60 minutes and 90 minutes. As expected, more polymer was created from monomer the longer it was left in the microwave. After 90 minutes, there was almost a 50% conversion!
After this, I finally got to start to work with the chemical we've been waiting for to arrive! I started the Baeyer Villager oxidation of 2-methylcyclohexanone. In basically the same steps as my first Baeyer Villager oxidation, I massed out 2-methylcyclohexanone and mCPBA. The 2-methylcyclohexanone was mixed with dichloromethane and the mCPBA was added scoop wise to the solution. One major difference I noticed was that the solution did not get frothy at all when the mCPBA was added (very different than the first time). This makes me think we may get different results, but that's what we're looking for in this research project!
Today I am going to continue the oxidation, so we'll see how things go!
Wednesday, January 16, 2013
Isolating the Monomer
Yesterday, we completed the Baeyer-Villager oxidation of cyclohexanone. The remaining liquid was rotavapped to remove the dichloromethane from the solution and just leave the monomer. I really thought this machine as awesome! It does the same thing as setting up a distillation, but reduces the time of the process by an amazing amount. Rotavapping only took about 10 minutes; I'm not sure exactly how long the distillation would have taken for this solution since we didn't run it, but I can imagine at least 45 minutes.
After the dichloromethane was removed from the product, Kristin (a senior at College of Charleston who is also working with Dr. Van Horn) took me upstairs to show me how to run an NMR on my product. We needed to run the NMR to ensure that what we were left with was only the monomer and no left over chemicals from earlier in the experiment. The NMR looked pretty good except there was a peak between 5 ppm and 5.5 ppm. After some research, Kristin and I realized that this peak represented some dichloromethane that escaped the rotavap process. There was no peak for mCPBA, which was the main concern, otherwise we would have had to redissolve the monomer in dichloromethane, extract it again, etc.
To double check our result, Kristin and I tried to run a TLC, but none of my product moved up the column. We weren't really sure why this happened, but we just moved on since we already knew what my product contained because of the NMR.
We placed my monomer under a vacuum to remove the rest of the dichloromethane. Almost immediately I could see it bubbling off. After everything excess is removed from the monomer, I expect it to look extremely viscous and kind of rubbery (hey, it really is a polymer!)
I was going to start the polymerization of caprolactone with Tin in the MARS (Microwave Accelerated Reaction System), but there was an error message when we turned it on. Also, my chemicals won't be arriving until late this afternoon, so it sounds like it's something I'll get to start on Thursday.
After the dichloromethane was removed from the product, Kristin (a senior at College of Charleston who is also working with Dr. Van Horn) took me upstairs to show me how to run an NMR on my product. We needed to run the NMR to ensure that what we were left with was only the monomer and no left over chemicals from earlier in the experiment. The NMR looked pretty good except there was a peak between 5 ppm and 5.5 ppm. After some research, Kristin and I realized that this peak represented some dichloromethane that escaped the rotavap process. There was no peak for mCPBA, which was the main concern, otherwise we would have had to redissolve the monomer in dichloromethane, extract it again, etc.
To double check our result, Kristin and I tried to run a TLC, but none of my product moved up the column. We weren't really sure why this happened, but we just moved on since we already knew what my product contained because of the NMR.
We placed my monomer under a vacuum to remove the rest of the dichloromethane. Almost immediately I could see it bubbling off. After everything excess is removed from the monomer, I expect it to look extremely viscous and kind of rubbery (hey, it really is a polymer!)
I was going to start the polymerization of caprolactone with Tin in the MARS (Microwave Accelerated Reaction System), but there was an error message when we turned it on. Also, my chemicals won't be arriving until late this afternoon, so it sounds like it's something I'll get to start on Thursday.
Friday, January 11, 2013
Separating the Organic and Aqueous Layers
After my solution stirred overnight, I came to the lab today to find exactly what I was hoping - a pretty clear solution with everything dissolved. The goal for today was to separate the organic layer from the aqueous layer using acid/base extraction techniques.
The organic layer was first extracted from the aqueous with 50 mL of sodium bicarbonate, being careful to regularly vent the separation funnel. In the same manner, the organic layer was extracted with 50 mL of sodium bisulfite and then 50 mL of brine.
The organic layer was extracted multiple times to ensure that only the wanted product, the monomer, was left behind. No leftover mCPBA is wanted in the organic layer, so multiple extractions ensure the removal of any excess. There also shouldn't be any water in the solution. 2.99 grams of sodium sulfate, a drying agent, was added to the organic layer to remove any water droplets that may have made it through the separation of the layers.
The flask containing the organic layer was then covered with aluminum foil and left in the lab until the next time I get down to Charleston.
In reflection of today's work, I was excited to use acid base extraction techniques. This is something I spent a lot of time working on last semester with Dr. Bass. It was one of the first labs we performed and the first of many organic chemistry induced mental breakdowns of the semester! After practicing conceptual problems and having Dr. Bass endlessly repeat the same concepts to me over and over, it finally clicked. After overcoming this first obstacle in the course, I realized that if I had the dedication to study the material, no matter how hard it seemed, I would eventually master it and be successful in organic.
The organic layer was first extracted from the aqueous with 50 mL of sodium bicarbonate, being careful to regularly vent the separation funnel. In the same manner, the organic layer was extracted with 50 mL of sodium bisulfite and then 50 mL of brine.
The organic layer was extracted multiple times to ensure that only the wanted product, the monomer, was left behind. No leftover mCPBA is wanted in the organic layer, so multiple extractions ensure the removal of any excess. There also shouldn't be any water in the solution. 2.99 grams of sodium sulfate, a drying agent, was added to the organic layer to remove any water droplets that may have made it through the separation of the layers.
The flask containing the organic layer was then covered with aluminum foil and left in the lab until the next time I get down to Charleston.
In reflection of today's work, I was excited to use acid base extraction techniques. This is something I spent a lot of time working on last semester with Dr. Bass. It was one of the first labs we performed and the first of many organic chemistry induced mental breakdowns of the semester! After practicing conceptual problems and having Dr. Bass endlessly repeat the same concepts to me over and over, it finally clicked. After overcoming this first obstacle in the course, I realized that if I had the dedication to study the material, no matter how hard it seemed, I would eventually master it and be successful in organic.
Thursday, January 10, 2013
Adding Sodium Bisulfite and Sodium Bicarbonate
Today I continued the oxidation of cyclohexanone. I came back to the lab and the solution that was left to stir overnight was completely dissolved. The solution was transferred to a 1000 mL Erlenmeyer flask (for reasons that will become clear later in this post).
Dichloromethane was used to transfer any remaining product from the RBF to the Erlenmeyer flask. After rinsing, the tots amount of dichloromethane in the flask was approximately 100 mL. 50 mL of water was then added to the flask.
The next step was to add 1.3 equivalents (relative to the mCPBA) of sodium bisulfite, followed by 1.3 equivalents of sodium bicarbonate. I calculated the amount of each chemical to be massed out through stoichiometry, resulting in 5.63 grams of sodium bisulfite and 4.55 grams of sodium bicarbonate.
The sodium bisulfite was added to he solution first in small scoops. The reason why the solution was transferred from the RBF to the Erlenmeyer flask now become clear: when the sodium bisulfite came Ito contact with the solution in the flask, it created a bubbly, frothy layer on top of the solution. The solution was transferred to ensure nothing spilled out over the top of the flask and out onto the counter.
After all of the sodium bisulfite was added, the sodium bicarbonate was added in the same manner. The same frothy layer appeared when it was added. After all of the sodium bicarbonate was added, the solution actually became clear. This is when we knew it was time to cover the flask with foil and allow it to stir overnight to ensure everything reacts completely.
So far my experience has been great at College of Charleston. Everyone has been so welcoming and very helpful for anything I might need. I feel so blessed to have found such a great group of people to work with this January. Right now I feel like I'm being a little clumsy in lab, but hopefully this is just nerves and will go away soon.
Dichloromethane was used to transfer any remaining product from the RBF to the Erlenmeyer flask. After rinsing, the tots amount of dichloromethane in the flask was approximately 100 mL. 50 mL of water was then added to the flask.
The next step was to add 1.3 equivalents (relative to the mCPBA) of sodium bisulfite, followed by 1.3 equivalents of sodium bicarbonate. I calculated the amount of each chemical to be massed out through stoichiometry, resulting in 5.63 grams of sodium bisulfite and 4.55 grams of sodium bicarbonate.
The sodium bisulfite was added to he solution first in small scoops. The reason why the solution was transferred from the RBF to the Erlenmeyer flask now become clear: when the sodium bisulfite came Ito contact with the solution in the flask, it created a bubbly, frothy layer on top of the solution. The solution was transferred to ensure nothing spilled out over the top of the flask and out onto the counter.
After all of the sodium bisulfite was added, the sodium bicarbonate was added in the same manner. The same frothy layer appeared when it was added. After all of the sodium bicarbonate was added, the solution actually became clear. This is when we knew it was time to cover the flask with foil and allow it to stir overnight to ensure everything reacts completely.
So far my experience has been great at College of Charleston. Everyone has been so welcoming and very helpful for anything I might need. I feel so blessed to have found such a great group of people to work with this January. Right now I feel like I'm being a little clumsy in lab, but hopefully this is just nerves and will go away soon.
Wednesday, January 9, 2013
Into the Lab
Today marked the start of what I have been looking forward to for so long: my first official day of undergraduate research. After Dr. Van Horn finished her lectures for the day, we headed into her research lab to begin my first project: the mCPBA oxidation of cyclohexanone by a Baeyer-Villiger reaction.
This is kind of like a practice for what I will be doing next week hopefully; the chemicals necessary for the reaction I will be running still haven't come in yet. The reaction follows a very similar, if not the same, procedure though so I will be extra prepared for when the chemicals do come in. The products I am making will still be used by Dr. Van Horn and other researchers for other projects that are being done, so my time is not being wasted.
The reaction scale we used today started with 5 grams of cyclohexanone (1 eq.) to 1.3 eq of active mCPBA. The mCPBA we used was 77% pure, as 100% mCPBA is very dangerous. After calculations, this resulted in 9.3 grams of mCPBA.
For our procedure, I massed out 5 grams of cyclohexanone, added it to a 300 round bottom flask, and dissolved it in 50 mL of dichloromethane using a stir bar on the stir plate. After massing out 9.3 grams of mCPBA, it was added in small scoops to the mixture over a 30 minute period. The mCPBA was not added in its entirety because it reacts with the mixture right as it is added and gets slightly frothy at the top of the liquid, so we wanted to prevent the solution spilling out of the RBF.
The mCPBA and cyclohexanone need to react overnight, so the solution was left on the stir plate and the procedure will be continued tomorrow. So far, things have been running pretty smoothly; I'm excited for what's next!
This is kind of like a practice for what I will be doing next week hopefully; the chemicals necessary for the reaction I will be running still haven't come in yet. The reaction follows a very similar, if not the same, procedure though so I will be extra prepared for when the chemicals do come in. The products I am making will still be used by Dr. Van Horn and other researchers for other projects that are being done, so my time is not being wasted.
The reaction scale we used today started with 5 grams of cyclohexanone (1 eq.) to 1.3 eq of active mCPBA. The mCPBA we used was 77% pure, as 100% mCPBA is very dangerous. After calculations, this resulted in 9.3 grams of mCPBA.
For our procedure, I massed out 5 grams of cyclohexanone, added it to a 300 round bottom flask, and dissolved it in 50 mL of dichloromethane using a stir bar on the stir plate. After massing out 9.3 grams of mCPBA, it was added in small scoops to the mixture over a 30 minute period. The mCPBA was not added in its entirety because it reacts with the mixture right as it is added and gets slightly frothy at the top of the liquid, so we wanted to prevent the solution spilling out of the RBF.
The mCPBA and cyclohexanone need to react overnight, so the solution was left on the stir plate and the procedure will be continued tomorrow. So far, things have been running pretty smoothly; I'm excited for what's next!
Tuesday, January 8, 2013
First Meeting
Today was my first official day of Interim! I drove down to Charleston and met with Dr. Van Horn of College of Charleston. We were supposed to meet yesterday, but she had to push back our meeting until this morning due to a training meeting she had to attend.
Speaking with Dr. Van Horn went very well! She was so welcoming and seemed very excited about my working with her over the next few weeks. She introduced me to a few professors that were in their offices, whom were all nice and very intelligent! We then headed to the organic lab for a tour. I must say at this point, I started to feel a little overwhelmed by all of the fancy machines they have and by the prospect of what I am actually going to be doing. However, Dr. Van Horn seems confident in my ability to do what needs to be done, so I suppose I should be as well.
We then headed back to her office and straightened out some logistics: transportation, what days and times I would be working, any materials I would need, the idea of getting a College of Charleston ID, etc. We even discussed the idea of studying abroad, as she knows two professors over in England, and working at College of Charleston over the summer.
Overall, I am very excited about this opportunity and think it will be a great stepping stone for gaining experience and opening up other opportunities for me down the future. I can't wait to actually do some work in the lab tomorrow!
Speaking with Dr. Van Horn went very well! She was so welcoming and seemed very excited about my working with her over the next few weeks. She introduced me to a few professors that were in their offices, whom were all nice and very intelligent! We then headed to the organic lab for a tour. I must say at this point, I started to feel a little overwhelmed by all of the fancy machines they have and by the prospect of what I am actually going to be doing. However, Dr. Van Horn seems confident in my ability to do what needs to be done, so I suppose I should be as well.
We then headed back to her office and straightened out some logistics: transportation, what days and times I would be working, any materials I would need, the idea of getting a College of Charleston ID, etc. We even discussed the idea of studying abroad, as she knows two professors over in England, and working at College of Charleston over the summer.
Overall, I am very excited about this opportunity and think it will be a great stepping stone for gaining experience and opening up other opportunities for me down the future. I can't wait to actually do some work in the lab tomorrow!
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