3 Biodiesel Titrations

Once you have your titration solution ready, it’s now time to start doing the titration. Remember on the board we explained how to do it. We’re basically going to take a known amount of the base solution. This is our .1 percent base solution, and I’m gonna pour some of this out into a little cup. It’s important that you never draw any of this with a syringe because it can contaminate this. That’s always why I put a little bit in a little cup. Seal it right back up, and that way I have a vessel for doing it. Now, I also have isopropyl alcohol, this is 91%, and I’m gonna put this in a vessel as well so that I don’t contaminate it either. To do a titration you have a sample of oil that you don’t know the acidity of, and you’re gonna get a syringe and you’re gonna suck up 1 milliliter of oil. These have milliliter markings on the side. These are kind of a handy little set of syringes. They actually say oil, alcohol, and titration solution. If you’d like these I carry them on my site as well at utahbio, but any syringe will do, but I just like it so I don’t mess up my syringes. I’m gonna suck up a milliliter of oil. I usually go a over and then I come back down. I’m gonna move it, I have a bubble on top that I want to get rid of. I’m gonna squirt down till I get to a milliliter of oil. I’ve got a milliliter of oil there. Before I put that into my solution here I’m going to put 10 milliliters of isopropyl alcohol in here. Now these actually have handy measurements on the side, so I can actually do it that way, but if you don’t you can suck up ten milliliters with a syringe, and get rid of your bubble. This is somewhat of a messy process so you want to wear gloves. You’ll notice that I have a little bit of oil and stuff around. There’s just no clean way to do biodiesel. I have yet to meet anyone who has. Buy some kitty litter if you want to make sure things are clean as the oil dries. Kay, so I’m gonna put ten milliliters of isopropyl alcohol into my jar here, and I’m gonna spray a milliliter of oil into this mixture. Now let the camera get up and kinda look at that real close. Now you’ll notice that is not really well mixed, and that’s because oil and water don’t like each other, so we’re gonna have to mix this up here. We’ll stir this here for a second. If you’d like you can heat the mixture a little bit. You don’t want to heat it too much ‘cause you don’t want to boil of your alcohol, but I’ve heard of some people heating the oil in the microwave in a little tiny dish before they use it. Our goal was just to basically get it to be one solution as you see here. To this mixture, we’re now gonna add about 3 or 4 drops of our phenolphalene. Again this is just a PH indicator, it’s nothing more than that. It’s not really important how many drops you need to put in here ‘cause all this is doing is indicating PH. Kay, so I’m gonna mix this up. Now what I’m gonna do is very slowly suck up some titration solution. I’ve got ten milliliters of titration solution in this syringe. I’m using a little stirrer and I’m just gonna start stirring this in. So I started with ten. I’m basically just looking for this to change colors. I don’t know if you can see that real well. Let me see if I can get you a closer view. As I put this in it is literally starting to change color drop by drop. You see that pink that’s occurring? Let’s see if I can do it a little differently here. That pink is my indicator solution. What’s going on is I’ve got a basic solution, I’ve got an unknown amount of acid, and it’s starting to neutralize that acid and taking the pH up over. How you know when you’re done is when that turns pink and stays pink for about 30 seconds. There we’re starting to come into it. There we’re a nice pink. Just a little bit more to be sure, and then we’ll sit and let that go for about 30 seconds. After 30 seconds if it is still that color, then we’re gonna write that number down. I’m gonna let this sit here while we look at our math. We started with ten milliliters, and we’re now at seven, so 8,9,10 that’s three, it took 3 milliliters of our titration solution to neutralize this acid in our oil. You’ll notice we’re staying this nice beautiful pink which is what we’re after there. A lot of times when you’re doing a titration it’s important to do it about three times to make sure that you’ve done it right. So we’re gonna do it, I’m gonna show you how to do it again one more time. ‘cause we kind of slopped around and made a little bit of a mess. You just want to make sure you always redo it, double-check your math. If after three times your number are plus or minus one, that’s your number. Average them out and that’s gonna be your titration number. So we’ll go ahead and pause here for a moment and we’ll get another one set up.

Kay, we’ve done our first titration and we got three so we’re gonna do another one. Again, one milliliter of oil. So I’ve got one milliliter of oil. Set that here. I’m gonna put ten milliliters of alcohol. Get that bubble out of the way. Ten milliliters of isopropyl alcohol into a container. One milliliter of oil. A couple of drops of my titrating solution. Again this is phenolphalene, phenol red, or toomric will work just fine. It also doesn’t matter how much of this I put in because it’s just my indicator solution. Now I’m gonna mix this up and get a really uniform batch of oil, alcohol and the indicator solution, and then using my titration solution, remember known amount of base, unknown amount of acid, in we go. We’ll move these out of the way so we get a little better view here. Slowly I’m just gonna start adding known amounts of base, starting at ten. We’ll swirl it around, it already started to turn a little bit pink which is what we want. There’s some pink and back to yellow, so we need a little bit more. Swirl it around. Oh, it’s getting there. Notice, it’s staying this good, nice pink color. Maybe just a little bit more. Okay here, so I’ve got that beautiful pink color. Phenol red turns sort of a redish color. Tumric turns kind of a pinkish color. This is phenolphalene you can see that it’s somewhat of a pink color, but your goal is just to hit that color and make it stay for about 30 seconds. Again, what that means is I’ve had an unknown amount of acid in the oil, a known amount of base that we add to it until we knock that pH, until we’ve neutralized it. This took, this is sitting at six this time. So we’re really close. We’ll do one more and then we’ll average everything together, then we’ll show you how much you’re gonna need to make a batch.

Kay, we’ll do our third and final titration. Again, we’re gonna do ten milliliters of alcohol. We’ll drop some indicator solution, one milliliter of oil, put it in, mix it up, and then we’re gonna slowly add in our titration solution. We’re gonna watch for the color change. Mix it around, it’s starting to turn. It’s getting there, and we changed. I’m at six, so I know, add a little bit more just to keep it there. So my first one was seven, my second was six, and my third one is about six and a quarter, so I’m gonna call this about six grams, or six milliliters extra. So what our titration would be, or how much we would add to our biodiesel that we’re gonna make, we’re gonna take 7.5 + 4 so about 12 grams we will add per liter of oil. So if we had 100 liters of oil we would add 1,200 grams of catalyst to that into our methanol to make biodiesel. And that’s how you do a titration.