 Now, after this there are few chemical properties of phenol that we have to discuss, in which again there are reactions only, name reactions are there basically, okay. So, you will see the next one we have that is the properties of phenol, chemical properties. So, next one you see I will write down here, chemical properties of phenol. Chemical properties is nothing but the chemical reactions involved in this method. The first reaction we have is formation of ester, how ester forms from phenol, okay. For this we take sodium phenoxide, okay and sodium phenoxide we can prepare from phenol. Because the reaction is this phenol and when it is heated with NaOH, in this reaction H2O goes out and we will get sodium phenoxide which is ONA plus H2O. This is the reaction we have, okay. Now, this sodium phenoxide is allowed to react with, we can use acid chloride for this purpose, acid chloride or we can also use acetic anhydride, both we can use, we will see the both reaction. So, when this acid sodium phenoxide is allowed to react with acid chloride or anhydride it forms phenolic ester, okay. Acid chloride is what? Acid chloride is nothing but CS3 C double bond OCl, this acid chloride. Anhydride is nothing but CS3 CO whole twice this anhydride, okay. Now, this reaction, the reaction with anhydride it takes place in acidic medium, okay. That is for that purpose we are using concentrated H2O4, the medium is the reaction is this, for this the medium of the reaction is pyridine, medium of the reaction is pyridine solvent we use, right. Now, you see how the reaction we have over here. Suppose, I am taking first acid chloride, okay. So, how the reaction takes place in acid chloride, okay. So, we have sodium phenoxide which is ONA on the benzene ring, ONA and when it is allowed to react with acid chloride this ClC double bond O, CH3 and the solvent we are using is pyridine. It gives NaCl and its oxygen attached with C double bond O, CS3 plus NaCl. This is what the reaction is. This is phenyl acetate. The name of this compound is phenyl acetate. The general name is phenolic ester, the general name is phenolic ester. Another reaction with anhydride we will see. For the reaction of anhydride we can also take OH here phenol directly and when it is heated with CS3C double bond O, OC double bond O, CH3 with concentrated H2SO4. It gives the same compound here which is OC double bond O, CH3 plus we will get CS3COOH. So, acetic anhydride we are using here, acetic anhydride and we are getting phenyl acetate, phenolic ester in this one. Okay. So, what happens in this? This H plus comes over here and oxygen will have the positive charge on it and finally this positive charge takes this bond pair of electron goes out as CS3COOH. Okay. So, we will get an SI carbocation here. We will have the positive charge on this carbon. So, this lone pair of this oxygen attacks onto this carbon, behaves as a nucleophile, attacks onto this carbon and we will get O, C double bond O, CS3, OH will have here, oxygen will have the positive charge on it. Now, to stabilize this positive charge, H plus comes out and we will get this anhyl acetate. Okay. So, this is the method of preparation of esters we have from phenol, acid chloride we can use or we can also use anhydride. Okay. So, now this reaction we have already done now. Another thing which is important over here is like I will write down the node, one node you must write down here and the point is the phenolic esters, phenolic esters on heating with, on heating with AlCl3, AlCl3 gives ortho, or an para-acyl phenol, ortho and para-acyl phenol. This rearrangement of acyl group at ortho and para position, actually what happens, this is acyl group, this group rearrange itself at ortho and para position. This rearrangement we call it as Fries rearrangement. This is known as, known as Fries rearrangement. So, Fries rearrangement is the rearrangement of acyl group of phenolic esters at ortho and para position when it is heated with AlCl3. Right. The solvent we are using is carbon disulfide. For this purpose, the solvent is carbon disulfide. So, you see this reaction, how this reaction goes. Suppose, I will write down the general term here which is the phenolic esters and which is nothing but this molecule. We have O, C O R. This is phenolic ester. Now, this R can be aliphatic or aromatic, both possibility we have. R can be aliphatic or aromatic means phenyl group C stage 5. Now, when it is heated with anhydrous AlCl3, anhydrous AlCl3 in CS2, carbon disulfide solvent. Okay. The product we get here is, the product we get here is OH and here we have C O R plus OH and CO. Now, this reaction is temperature dependent reaction. Right. Depends upon, depends on temperature, what temperature you are taking. Both product can be the major product depending upon the temperature of the reaction. Like at low temperature, like this product is the major product, major product at low temperature. Low temperature means the temperature should be less than 100 degrees Celsius. This is the major product, high temperature means the temperature is greater than 100 degrees Celsius. Okay. So, this reaction is temperature dependent reaction. Depending upon the temperature, we will get the major or minor product in the reaction. Okay. Now, you see the mechanism of this reaction, C O R. Anhydrous AlCl3 is a Lewis acid, electron pair accepted. And that is why the lone pair present on oxygen molecule, this lone pair is accepted by AlCl3 and it forms O, C O R will be as it is. And here, we have AlCl3 minus because it accepts lone pair of electron and this will have positive charge. Okay. Now, in the next step, what happens? This C O R comes out. Okay. Leaving this electron pair behind, C O R comes out. This one. So, minus C double bond O R plus. And with AlCl3 minus, Cl minus also comes out. Okay. On heating. So, it forms a ring with O AlCl2. Now, this acyl carbocation, this one C double bond O R plus. This behaves as an electrophile and the pi electron of benzene ring takes this electrophile. It attacks over here and this will attach onto the benzene ring like this. O AlCl2, C O R, we have hydrogen here, positive charge on this carbon atom, these two bond will be as it is. Right. Now, to gain aromaticity, this H plus comes out and this H plus leaving this bond pair of electron behind so that the aromaticity of the molecule is cheap. And this H plus combines with Cl minus forms HCl. So, the product here is O AlCl2, C O R plus HCl2. In the last step in H2O, AlCl3 goes out and it forms OH on the top and C O R at ortho position. Okay. So, this is the ortho acyl phenol, ortho substituent product. Same kind of mechanism we have at para position. The only thing is here, this pi electron comes over here and this attacks onto this carbon atom and we will get the product. Okay. So, same kind of mechanism we can draw for para position. Got it. If para position is occupied, then we only get ortho substituent product. Okay. If para position is occupied, then we only get ortho substituent product. One note I will write down here. If para position is occupied, we get only ortho product. We get only ortho product. So, this reaction is Frye's rearrangement reaction. The reagent used is and I address AlCl3, okay, in CS2 solvent. Okay, carbon, disulfide. Okay. There are a few more reactions in this. There are name reactions like cold skimmy reaction. We have rhymer-tymon reaction. Okay. So, all these reactions we will see in the next session. Thank you.