It could be picked up by another molecule of ethanol. The result of the experiment is approximately pure isopentyl acetate of probable yield. And actually, before I do that, let me make sure this guy can lose a proton to the medium. Concentrated sulphuric acid is added whilst swirling the contents and washed with methanol. He has now left as water.
So this guy gives an electron to the proton, but the end result is the hydrogen leaves. The mechanism of this Fischer- Esterification process is outlined as follows: Carboxylic Acid Alcohol fig. Both benzoic acid and methanol are relatively cheap to obtain from a commercial source as well as being easy to store with a relatively long shelf life. In another word, the long chain alcohol cannot be used to react with carboxylic acid. And then this guy can take the electron back. This experiment aims to synthesize an.
Stage 3: The intermediate is stabilized by the elimination of water. He gave an electron to a hydrogen proton. And you would be tempted to call it heptanoic acid, but it is no longer a carboxylic acid. A better thing to do, instead of drawing these one-way arrows is to show that the reaction could actually go in either direction. It's already hogging these electrons. It can go in either direction.
Sulfur has six valence electrons, just like oxygen. This might be due to the mixture contain some impurities, so the temperature may fluctuate in the wider range of temperature. These are kind of in equilibrium with each other. Now, the reason why this is such a strong acid, is that if either of these oxygens take the electron from this proton, so actually give away the proton to the solution, there's a ton of resonance structures here. I'll actually draw its structure, because I always find it frustrating when people just write just the formula here without the actual structure, because the structure actually shows you why it's so acidic.
Let me do it in that same color. The methoxy group tends to leave the tetrahedral intermediate to form a stable methoxide, so the negative oxygen atom donates the electron back to the carbonyl carbon. The mixture is being refluxed for 1 hour, the mixture is poured into a separating funnel with 150ml of water after cooling. Let me draw it as getting picked up by another molecule of ethanol. Plus sulfur, two double bonds, two oxygens.
That ethanol has lost its hydrogen. Eventually, another hydroxyl group will donate the lone pair electron to the attached oxygen atom to form a more stable intermediate. Acetic acid was added to 4-methyl-2-pentanol, which was catalyzed by sulfuric acid. We started with a heptanoic acid, and now we have an ester. So one, two carbons, it has this original hydrogen over here. The boiling point of the ester was 143° C, only one degree off from the theoretical boiling point of the ester 1,3-dimethylbutyl, 144 ° C. The vapors were blocked from escaping the solution by a stream of cold water running up the reflux column.
It's just as likely to go from here to here as it is from there to there. So let me read redraw my heptanoic acid. So, there is more attraction to the lone pair electrons around oxygen which makes the hydroxyl group partially negative. The concentrated sulphuric acid is added as a catalyzed in this experiment. And this tells you what's on the other side of the oxygen in the ester.
Maybe we're in a solution of ethanol, and if we are in a solution of ethanol, it'll just add protons to the ethanol itself. So this guy can grab a proton either directly from sulfuric acid or maybe from one of the protonated ethanols, either one. Let me draw it like that. The purpose of using catalyze is to speed up the esterification because it is a slow process. These techniques allow the chemist to derive functional groups and isolate unknown compounds that can verify and identify unknown compounds often obtained through academic and commercial laboratory research projects.
Using the chemical and physical properties of organic compounds, an ester was catalyzed from the reaction of a carboxylic acid with an alcohol, producing an odor similar to that of pear oil. The process is a continuous reversible process until the equilibrium is reached. That hydrogen is now neutral. And this ester right here, and we'll probably talk more about esters in future videos, this ester right here, just to give you a hint of how to name it, you first start with the group that's attached to this oxygen right here. We now have two, three, four, five, six, seven carbons. So this proton might get lost, maybe by one of the other ethanol molecules, so let me draw that.
Or if I just actually grab protons in our reaction, that actually might make it a little bit simpler. It now has a negative charge. But we're now over here, and let me redraw my heptanoic acid. So you can imagine this guy right over here. So if I were to draw it, it would now look like this. Next is the addition of sodium carbonate to neutralize any acid which has been distilled which was later tested using litmus paper, washing with ice water, washing with calcium chloride and addition of anhydrous calcium chloride. Esterification reactions take place in the presence of an acid catalyst or dehydrating agent.