michaelkim's blog

            In this lab, nutmeg was used to form trimyristin via extraction, filtration, recrystallization to simply withdraw or isolate it from nutmeg. Trimyristin with sodium hydroxide and water can form glycerol, sodium myristate, and myristic acid as seen in the reaction scheme. The first step of this lab experiment was to measure and weigh ground nutmeg (1 g). Being precise is better so exact 1 gram was taken. In a flask, with nutmeg, tert-butyl methyl ether (3 mL) was added to boil for 10 minutes. After distilling them, boiling them, and filtrating them first set of crystals were formed as a solid in a yellowish substance should form. This is called the crude trimyristin which about 0.622 g of the crude was obtained. Then acetone, sodium hydroxide, and ethanol were added to obtain crystals. 170 mg of crystals were obtained. When it was recrystallized the second time, only about 102 mg of crystals were obtained or recovered back. There were three majors parts to this lab experiment. First being extraction, second being recrystallization of trimyristin, and then lastly hydrolysis. After evening hours or overnight drying, the final weight of the crystals was 0.051 g with the melting point of 50-52. To find the % yield, theoretical of 0.170g x 1 mol / 723.16 then multiply by 3 mols and then divided 0.051 by 0.161 then multiply by 100 to get percentage. It ended up being 31.68%.

            Setting up sand bath is the first thing to do, turning it up to about 30 but not higher. Weigh and take about ground nutmeg (1g). Then use a round-bottomed flask and with the help of a funnel, transfer the nutmeg over into the flask. Add tert-butyl methyl ether (3 mL) and add a few boiling chips. Use plastic connector then distillate using air condenser. Use the small three-pronged clamp to help assist. Allow the mixture to boil very gently and the mixture with nutmeg will boil violently. Make sure it doesn’t bump out of the flask.  Heat it for about 10 minutes then remove from the heat and let it sit to cool down. Micro-scale filtration needs to be done after using a tiny plug of cotton in a glass pipet. Also, use a clean and dry Erlenmeyer flask (25 mL) Once it is all done, remove the condenser, tip the round-bottomed flask and transfer it over to the top of the filtration apparatus. Let gravity take care of the rest, but when it becomes slower, gently squeeze to apply pressure to complete the filtration. After repeating to get everything transferred out, add fresh tert-butyl methyl ether (2 mL) and do the same steps. That is called rinsing. It will help ensure that no trimyristin is left behind. Use gentle stream of air over the solution so all the solvent will evaporate. Yellowish solid should now remain. This is the crude trimyristin. Raise the sand bath to 30 again and recrystallize trimyristin. Crude trimyristin should be air dried for another 5 minutes. Then add acetone (1 mL) per crude (50 mg). Crystals should now start forming, but if it is not then scratch the inside surface a bit with glass stirring rod. Use ice water bath and let it sit for 15 minutes. Collect crystals now by vacuum filtration. Cover the crystals with ice-cold acetone (1 mL) and allow air to pass over the crystals. Hydrolysis now must happen using trimyristin (60 mg) and use new clean RB flask. Add 6 M sodium hydroxide (2 mL) and 95% ethanol (2 mL). Use boiling chips once again and put it on the sand bath for 45 minutes. During hydrolysis time, recrystallize the remaining trimyristin a second time but do it with room temperature for 10 minutes. Collect the MP and weight.  After 45 minutes passes by, allow the flask to cool to room temperature and put it in a beaker with water (8 mL). Then carefully drop hydrogen chloride (2 mL), myristic acid should disappear by precipitation. Cool the beaker after for 10 minutes and stir it. Filtration happens and crystals starts to show. Let it dry overnight and weigh it and take MP (also the % yield).

Post-lab Question:

           Using two TLC plate, one had to mark three spots 1cm above the bottom of the plate. If 3 UV active spots were in the crude material and co-spot TLC plate, and only one spot had the same R_f as the starting material and the other 2 are very different, predictions for the 2 non-starting material spots could be something in the middle of the mechanisms. There are four parts to the mechanism, so the second and third part of the mechanism would be the 2 non-starting material spots. This is due to the rate of the hydride attack on the carbon double bonded to the oxygen. It depends heavily on the R group present, and the more electron deficient it is, the faster the hydride can attack. But because they are different from the starting material spot, it would mean that it was caught somewhere in between and could not fully reduced and go to completion.

Post-lab Question:

            If 3 UV active spots were in the crude material and co-spot TLC plate, and only one spot had the same R_f as the starting material and the other 2 are very different, predictions for the 2 non-starting material spots could be something in the middle of the mechanisms. There are four parts to the mechanism, so the second and third part of the mechanism would be the 2 non-starting material spots. This is because of the rate of the hydride attack on the carbon double bonded to the oxygen. It depends heavily on the R group present, and the more electron deficient it is, the faster the hydride can attack. But because they are different from the starting material spot, it would mean that it was caught between and could not fully reduced and go to completion.

            By using benzoin, ethanol, sodium borohydride, water, 6M HCL, and acetone the goal was to recover as much crystals back which 68.5 % was obtained. Benzoin (0.5g), ethanol (4mL) was used at first into a flask (25mL). Adding sodium borohydride (0.1g) and swirling it for 20 minutes made the benzoin very white. Adding water (7.5mL) and 6M HCl (0.3mL) then vacuum filtrating made the substance to come together as one big chunk. Using acetone, it was recrystallized. Then two TLC plates were used. On the left was starting benzoin for both plates. On the right was recrystallized one for the first one but the second one had the crude one. The middle had both of it contained. Running the TLC plates was the next step and by using the chamber and after it had dried the UV light was used to mark the spots. Desired reaction product will go all the way to the top without separating instead of staying down low when the TLC plate is used. There were total of 4 spots including the starting material. Benzoin had one spot, recrystallized in the first plate had 1 spot as well as for crude. The middle however that contained both the starting benzoin and either recrystallized or crude had 2 different spots. Instead of water, what if acetone was used? Acetone can dry up a substance quicker than water so by using acetone instead of water in the reaction equation, maybe it would have been more accurate and faster. Also, by using less amount of each substance, time could have been saved and it could be a possible modification needed for this lab. There is a double bond on the oxygen in the first equation, but by taking away the double bond, the hydrogen gets added to the oxygen in the final reaction. There were many times in this lab where waiting and swirling for a long time occurred, so by cutting down the amount would do a better faster job.

Experimental Procedure:

            First, add benzoin (0.5g) and ethanol (4mL) to an Erlenmeyer flask (25mL) swirling at room temperature until it is all dissolved. Add sodium borohydride (0.1g) using a micro spatula in small amounts for 5 minutes (swirl for addition 20 minutes at room temperature). Cool the mixture using ice bath, add water (5mL) after and 6M HCl (0.3mL). Wait 15 minutes to add more water (2.5mL). Then collect the product using vacuum filtration (reserve 1-2mg for TLC analysis) after 15 minutes. Recrystallize from acetone, using 25 mL flask. Let it all dry and come back for evening hours. MP, yield %, and mass needs to be determined. Dissolve a small amount of benzoin, using recrystallized product and reserved crude product in ethyl acetate. Spot 2 TLC plates, with starting material, reserved crude product, recrystallized product, and a spot that contains both in the middle. Run the TLC plates in 9:1 CH­­₂Cl₂: ethanol. Add eluent to TLC developing chamber, use tweezers to carefully put the TLC plate in the chamber and screw the cap. Allow the solvent to run from the baseline to about 1cm from the top. Remove the TLC plate when it is ready marking the solvent from it and allow it to dry. Use UV light and mark them once it is all dry. Tape the plates on a sheet of the lab notebook paper or take a picture and draw into the lab notebook. 

Contact

Michael Kim

michaelkim@umass.edu

230 Thicket St.

Weymouth, MA 02190

781-708-1552

Education

University of Massachusetts Amherst

Amherst

May, 2019

Bachelor’s degree

3.3 / 4.0

Experience

AP biology tutoring in Weymouth (2015-now), learned to teach. If I can’t teach the material that means I don’t know the material so it was a good lesson to teach myself by teaching.

Quan’s Kitchen in Weymouth as a manager 08-12-14 until now, learned basically everything through this management job. Not only did I learn to deal with finance but to also please customers and coworkers which is very important skill to have.

Assistant teacher at Quincy YoungSang Korean School in high school, once again great way to learn how to teach. Learned to work with my students.

Praise team leader at Quincy First Presbyterian Church high school until now, learned to lead and being a leader and leading a group of people is a very important skill to have in any given field.

SDT sorority houseboy in Amherst This semester, served food and did dishes mostly but taught me patience and to serve others before me.

Missions Trip with my church at Mexico Junior year in high school, the kids I met here were a blessing. I learned to truly love and gave me passion to continue to serve the people in need.

Father Bill’s homeless shelter in Quincy High school until now, just like the missions trip, I learned to serve food, talk to them, and share the gospel. I think it is a skill that one must acquire in order to be successful, putting others before yourself and not being selfish.

Honors, activities, and outreach

Health award (forgot the name of the award but it was given in health class) Sophomore year in high school

Wild Cat award in Varsity basketball Senior year in high school was given for being the Most Valuable Player

Abigail Adams Scholarship Senior year in high school for doing better than average on MCAS

Zeta Beta Tau Greek fraternity Sophomore year until now

University of Massachusetts Minutemen Marching Band since freshman year until now

FTK (For the kids fundraiser) Junior year in college

Get on the ball (For children’s hospital) Sophomore year in college

Skill

Diligence, able to work at a fast pace, and ability to serve others.

I learned to work with many people and to be able to get along with them. Not only will I get the job done well but I will get it done at a fast pace. I am extremely diligent so I will not lack off. My goal is to be able to please and support others if they are in need because I love to serve others.

If only one pregnant mom and her puppies could be saved, I think that New Guinea singing dog breed should be the breed of dog that should be saved. If you are unsure why this certain breed should be the way to go, this is because they live the longest out of any living dog breeds. And you already know that dog years and human years are not the same meaning that if dogs live 10 years, it is not equivalent to humans living 10 years. New Guinea singing dog breed can live up to 18 years which is really long for dogs. Not only are they one of the rarest dog in the world, but there isn’t too many of them in this world. It is originated from New Guinea and it is well known for its singing howl. 

If we don’t take care of them, they might all die. Just because they are the longest living breed does not mean that they can just be treated without care. There’s no price that can be tagged or placed on them because they are already so rare. Research has shown that they are one of the more friendly and gentle dogs to humans. Not only will this be good to us, but for themselves. I am convinced that saving this breed can be the best solution as scientists can try to figure out a way to breed more of them or come up with a new solution, but at least we know that they are the longest living breeds so it gives us the time to come up with something.

1. As the temperature goes up, the retention time of the gas is decreased. As the temperature is rising, the gas needs to find its equilibrium between the two phases one of them being mobile phase and the other being gas absorbed phase called stationary.
2. Peaks for the impure sample which in this case will be cyclohexene will be easily identified. Area would be different for concentration of impure sample and concentration of cyclohexene. The different number of peaks can help identifying how many number of impurities there are apart from cyclohexene peak.
3. Type the formal reports, do the post lab questions and do the write ups.
4. Weigh the crystals and find boiling point at the evening hours before the lab tomorrow.

By using phosphoric acid, dehydration of cyclohexanol was possible. Also, to determine if it was whether alkene or alkane, bromine was used to yield a trans- 1,2-dibrominated product. Oxidizing cyclic alkene to a dicarboxylic acid. Having used all the procedures done before this experiment such as finding melting points, densities, molecular weights, and more combination of extraction, distillation, recrystallization, chromatography was done. Chromatography displays how polluted it is with different liquids. It was about 85% cyclohexanol and 15% something else. In its cyclohexene at about 2900 and 1440, there was a scan done. Higher the temperature of the liquid was, the longer the compounds need which results in better separation. Exactly 2.02 grams of cyclohexanol was used and having to find % yield, different combinations of methods were used to recover. Boiling points were at 63 to 69 degrees as first drop occurred at 66 degrees. At the end, 0.313 grams were recovered which is about 15.5% recovered from the total 2.02 grams used. The second part of the experiment was with cyclohexene and cyclohexane. Depending on which liquid was used, the colors were changed. Bromine in dichloromethane and 1% potassium permanganate and 10% sulfuric acid were used. The only unaffected color was cyclohexene with bromine in dichloromethane. All the other three tested were affected. Using cyclohexene with potassium permanganate with sulfuric acid turned it dark purple. Cyclohexane made the two given liquids either reddish-orange (with bromine in dichloromethane) and dark purple (with 1% potassium permanganate and 10% sulfuric acid).