today we're going to be going over the synthesis of aspirin this is an introduction to organic chemistry you will learn how to synthesize it from starting materials the first thing we're going to do is use salicylic acid and we're going to weigh it to 1 grams so we've got our milligram balance here that goes to 3 decimal places so that you can get your milligrams so we're going to take this salicylic acid and we're going to put it into a 6-inch test tube okay next we're going to go ahead and add our acetic anhydride so we've got this right here you know measure that in a graduated cylinder you're going to put in two point five mils go ahead and pour that in with this you can kind of rinse down the sides of the test tube if you have a bunch of stuck salic acid and that I'm going to take our stirring rod give it a little stir then we're going to add three drops of phosphoric acid so we're going to do this very carefully one drop at a time add a drop let's get a little stir and another drop give it a little stir and add a third drop go ahead and stir that up make sure it's nice and stirred and then we're going to put this in our hot water bath and that is going to be in there for 15 minutes and we're going to stir it occasionally throughout that 15 minute period this is where the starting materials are reacting with each other to form our aspirin [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] okay so now 15 minutes has gone by you can see all of our cell and has dissolved you're now going to take out the test-tube I'm going to use these clamps because this water is not boiling but it is at seventy eight point six degrees Celsius so my tube is going to be hot go ahead and grab this and carefully transfer it into the ice bath I am now going to add chilled di water and I'm going to add 10 mils total but I'm going to add it gradually in small portions there we go now we got 10 mils so I'm going to go ahead and add a small portion in here just like a couple males and then I'm going to grab my stirring rod and stir that around you can see that I'm already starting to have products form in there go ahead and add a little bit more I'm gonna go ahead and add the last portion all right I'm just so that's gonna sit for ten minutes in the ice bath and you can already see there's a lot of aspirin in there but it's going to keep developing [Music] [Music] [Music] all right so I've got to get my vacuum filter set up all set up so we're gonna have this tube which is stored underneath the sink you got to make sure you attach that onto the bottom of the faucet and you're gonna have this Luber tube which is vacuum tubing that goes on to the side arm of your faucet and then it goes on to the side arm of your filter flask when you're putting this onto the filter flask you do need to get it on there nice and tight but kind of wiggle it on don't just jam it on or you might end up breaking this last sidearm you're then going to put in this black ring that is going to provide a seal between the filter flask and the funnel you are then going to pre weigh a filter in a way boat you are going to be weighing you are finding your product to actually offer the filter so you need to make in the weigh boat so you're going to need to make sure that you have an exact mass on the two of them together for this I got two point six five two grams and you want to go to that third decimal point that milligram place so we're going to go ahead and turn this on we're going to take filter paper place it on the top of the funnel make sure it's nice and centered you're then going to take a small amount of water and pour it on top of the filter that's going to help make sure the filter is down and in place before you start pouring your product in we are then going to take our product and pour it onto the filter we may need to use our stir rod to help encourage some of that product to come out there's a lot in there and it's gotten kind of stuck in there we are now going to use five mils of di water make sure it's nice ice-cold di water this is just going to be a rinse so this is not super important that it's exactly five mils but it should be right around five mils I'm going to use that to rinse out this tube so I'm gonna pour it in there do a couple of portions here pull it around pour it over my product one more time kinda encourage all that product to get unstuck from the sides of the tube and dump that in alright then we're going to use one more five mil portion to rinse off the product first I'm going to take my stir rod and I'm going to kind of spread my product out a little bit so we make sure all areas of it get rinsed and so that it'll dry faster and just kind of tap it around break it up a little bit so it's not in chunks and then I will take my rinse off mr. right a little bit and then just pour this water over my father now that's going to need to sit on the filter for a little while until it dries okay so now my product is fairly dry so we're going to go ahead and take it off it says in the manual to put it on a paper towel but I find that it works better to put it directly into the dish because you often end up losing some if you try to put it on to the paper towel I'm actually going to use one of these guys instead of mr. right I'm going to carefully pick up the edge of my filter and as you can see a lot of the product just kind of falls off the pill filter that's why we weigh it back in a dish rather than just weigh back the filter paper carefully transfer that into the dish and the rest of the product that fell off into the fall at this point you're going to put your tray into your drawer and let it sit until the next lab period if I then it should be completely dry and you can weigh it back to calculate your percent so now we're going to make up our standard solution this is going to be a one point standardization instead of a beer Lambert pot like we did earlier in this semester we are going to be doing this with just one point a standard and using that for comparison to figure out the concentrations in our products so the first thing we're going to do is put in the standard sales silic acid solution that's going to be 5 mils and that is in a 25 mil volumetric to put in the 5 mils you use this and a 5 mil glass pipette you're going to insert the glass pipette into your pipette holder and then you're going to you can draw up solution and let it back out now that we have the standard in here we are going to add 2 point 5 mils of 95 percent ethanol into the flask for this we can use a graduated cylinder it's just the standard that needs to be super precise so we need to use the glass pipette I'm gonna carefully pour this ethanol in here then I have my iron solution that is again 2.5 mils you can see it turned purple immediately I'm now gonna fill this to the line with DI water you can see a little line right there that is your mark that you're going to fill it to and you need to be really precise with this so we have these little bottles with DI water that help you to be super precise and so now that I've gotten to the end I'm gonna go real slow to make sure I get it right at the line there we go right on the line and then I'm going to put in my stopper and I'm going to invert this 15 times the thoroughly mix when doing this make sure you put your fingers on either side of the cap so that it does not fall out and you don't lose any of your solution okay now I can go ahead and move to the spectrometer okay so here we are at the spec I have my standard solution that I just made up the spec I set to 525 nanometers that is the max wavelength the lambda max for this particular complex that we made up and we are going to use this standard to do a one point calibration that we can use to figure out the molar absorptivity I now need to figure out if my two cuvettes are within 1% of each other so I have one keep that with the eye in it put a little bit more in there I'm going to put it in I'm going to press the zero absorbance button to set it to a hundred percent transmittance and it's at a hundred percent now I'm going to take my other cuvette and make sure that it matches so I'm going to put di into here I'll place that in and that is at exactly one hundred point zero so they match so that's great I'm going to empty these out and I'm going to be using one of these is my blank so I already have it set to they were exactly the same so it doesn't matter which one I use as my blank the other one I'm going to dry out any amount of di that is still in the cuvette will dilute my standard and then I will not have an accurate reading okay now that my cuvette is nice and dry I'm going to go ahead and transfer in my standard solution for this I'm going to use a little glass pipette and bulb it's easier than trying to pour it in all right I'm going to since I was touching the outside of this a bunch I'm going to take a chem wipe and I'm going to wipe down the outside so that's a little bubble in there so I'm going to look it a little bit to try and get rid of those bubbles okay wipe down the outside make sure it's nice and clear stick that into my cuvette or into the spectrometer and that is reading at thirty eight point nine percent transmittance so that is the point that I'm going to use to find my molar absorptivity you can take that out we are now going to rinse this cuvette a couple of times with DI and once again make sure it is nice and dry okay it is now time to make up our compound solutions so this has to be done on day two because we will need our dry crude product and we will need to recrystallize and get a cleaner final product and then we will be comparing the percent transmittance and the smaller objectivity of the two so today we come back on day two our product is nice and dry on the filter in our way boat we are going to weigh the whole thing together that comes to three point six five five grams and we can subtract the weight of the filter paper and dish to get the weight of just the product which will get allow us to calculate the percent yield we now want to set aside point two grams of our crude product we will be using this in step D and then we will recrystallize the rest of our product so I have another way boat here I'm going to tear that and then I'm going to porch 0.2 grams of this crude product into this way boat ok that is at point one nine nine so that's close enough I'm now going to take the rest set that aside and take the rest of my food product and we crystallized that so I just have this hot water bath set up here with water Addie I already in it this is at seventy five point six so that is good I'm going to take my six inch test tube I already have a hot test tube in there with the eye in it because we're going to need hot di water I'm now going to put my crude product into this six inch test tube and I'll break it up a little bit so that it's easy to pour into the test tube you don't want to scrape your filter paper too much or you'll get that's a filter paper in there but just kind of brush off the excess product all right at this point I'm going to put in two point five mils of 95% ethanol a bit much there there we go I'm going to pour this into my 6-inch test tube with my product and place this into the hot water bath as soon as it starts spoiling I want to be able to remove it but I also need all of this to dissolve so I'm gonna give it a little stir to help encourage everything to dissolve it's very important that it all dissolves that's more important than having it in there a minute after it starts boiling okay at this point it is all dissolved and it is simmering so I'm going to go ahead and take it out put that in my rack and now I need to put in five mils of the pre-warmed DI water that I have here a little bit over there there's no waste okay so now I'm going to add this into my test tube and now I'm going to let this sit if solid had immediately appeared when I added the water I would have needed to reheat it and then let it cool down again but that was not the case so now I'm going to let it sit at room temperature I'm not going to touch it I'm just gonna let it sit come down to room temperature and after that then I will move on to cooling it now I am going to move on to doing the speck portion of my experiment Part D this will be to determine the percent of salicylic acid in the product so in here I have two point five mils of 95 percent ethanol to this I am going to add about point one grams of the crude product so I'm going to weigh that out this needs to be written down exactly how much you did use so that you can calculate the concentration okay so that is exactly point one well that's stabilizing same point Oh 96 so that's close enough okay so now I have my point zero nine six grams of crude and I'm going to put it into my 2.5 mils of ethanol that are already in my 25 mil volumetric I am going to take a clean way boat and place my volumetric into it that way if I spill any product while I'm trying to get into the volumetric I can just get it out of the bottom of the way boat okay so that was good I got it all in there so I'm going to need to swirl this around a little bit make sure that it's all dissolved a little bit stuck on the sides so I'll need to wash that in with the iron solution so actually I'm gonna just stop her it make sure I get it all dissolves before I move on to the next step okay it's all dissolved now so now I can add my iron solution so I'm going to add again 2.5 mils go over there so they tend to do there we go I'll carefully add that into my volumetric you can see it already starting to turn color in color I'm now going to add my di right up until the line just like we did when we were making up the standard solution there we go stopper that and invert it 15 times okay I'm now ready to do the reading on this so now I'm going to get a percent transmittance on this how this works is the unreacted salicylic acid is what reacts with the iron complex and gives you the color so we can inversely figure out how much of the aspirin product we made based off of what the concentration of salicylic acid in this solution is I am going to be zero the spectrometer is good to do that before you run any experiments just to make sure that's the blank all right I'm going to wipe down first I'm going to get rid of the bubble gently flicking it and then I'm going to wipe down the sides of the cuvette with my chem wipe and put it in there and so what I get here is 58.3 now this has been sitting for about 20 minutes it has come down to room temp you can see the tiniest bit of crystals starting to form on the bottom of my test tube I'm now going to put this into the ice water and that should initiate the rest of the crystals to form this is going to stay in here for about ten minutes or until we see a good amount of crystal formation sometimes it does take a little bit longer [Music] [Music] [Music] [Music] [Music] I have my crystallized product here as you can see we have a lot of nice crystals I have my pre-weighed way boat and filter paper and take my filter paper and put it into my phone I'm going to turn on the water so that I get vacuum I'm going to pour a little bit of cold CI on to the filter to help hold it down and then I'm going to pour my crystallized product on to the filter and it may not want to altitude well let's write out my crystals a little bit to help facilitate drying I'm going to give this a tiny rinse with a tiny bit of di just a little bit throw that around dump it in and we will now wait for this to dry as you can see this is nice and white as compared to the crude which had more of a brown tinge to it this is very nice and white and that's because it's pure recrystallized product once it is mostly dry you can turn off the water you wanted to take your product and filter paper and put it onto a watch glass to help facilitate drying I wanted to be kind of spread out so that it dries faster we go this can now sit for a little bit and then you will find the mass of your product and use that to calculate your percent yield so now it is nice and dry I'm going to transfer all of this into my pre Wade way boat and I'm going to find the mass and now that I have the mass I can subtract my initial weight of the weigh boat plus filter paper and get the weight of my final recrystallized product and use that to calculate my percent yield so here I have my recrystallized product it's nice and dry I'm gonna weigh out about 0.1 grams and I will use this in making my solution that I will then use to find the percent transmittance and the molar absorptivity okay this is that exactly 0.1 grams and it take a clean way boat and put my volumetric which already has 2.5 mils of ethanol in it I'm going to put that in my way boot and I'm going to carefully transfer the product into the volumetric okay I want to make sure this gets totally dissolved and I want necessarily be able to see that once I add the ions I'm going to make sure that it's totally dissolved now I'm going to invert it a couple times just to get all the stuff that's stuck on the sides off and that looks nice and dissolved so now I will add two point five mils of the iron solution [Applause] it's not any good too much there there we go you can see it turning purple already I'm now going to fill to the line with DI water stop her that and invert 15 times okay I am now ready to move over to the specter potometer and take my reading so you can see this is purple colored I'm going to check and make sure that this is still blanked correctly again the purple color you see here is due to the cell silic acid so that's unreacted starting material and we can use that to figure out how much reacted aspirin we created and that reads sixty three point five i will now disassemble my vacuum filtration unit so i'm going to take off the vacuum tubing this will be returned to the stockroom I'm going to take off this part and this goes underneath the sink I will then disassemble my filtration unit and use the sink and wash it all out and then we turn all three pieces to the stacker for this experiment all of the waste products can go down the sink [Music] [Music] [Music] [Music] [Music] [Music] [Music]