and you can combine all this together to give one overall equation: You need to follow this through really carefully, because the two products of the reaction overall can look confusingly similar. Taking a general case of a reaction between ethanoyl chloride and a compound XNH2 (where X is hydrogen, or an alkyl group, or a benzene ring). This particular compound is N-methylethanamide. \text{XNH}_2 + \text{HCl} \longrightarrow {\text{XNH}_3}^+\text{Cl}^-, \text{CH}_3\text{COOH} + \text{XNH}_2 \longrightarrow \text{CH}_3\text{COO}^-{}^+\text{NH}_3\text{X}, (\text{CH}_3\text{CO})_2\text{O} + \text{NH}_3 \longrightarrow \underset{\color{#467abf}{\text{ethanamide}}}{\text{CH}_3\text{CONH}_2} +~\text{CH}_3\text{COOH}, \text{CH}_3\text{COOH} + \text{NH}_3 \longrightarrow \underset{\color{#467abf}{\text{ammonium ethanoate}}}{\text{CH}_3\text{COO}^-{}^+\text{NH}_4}, (\text{CH}_3\text{CO})_2\text{O} + 2\text{NH}_3 \longrightarrow \underset{\color{#467abf}{\text{ethanamide}}}{\text{CH}_3\text{CONH}_2} + \underset{\color{#467abf}{\text{ammonium ethanoate}}}{\text{CH}_3\text{COO}^-{}^+\text{NH}_4}, \text{CH}_3\text{COCl} + 2\text{NH}_3 \longrightarrow \text{CH}_3\text{CONH}_2 + {\text{NH}_4}^+\text{Cl}^-, (\text{CH}_3\text{CO})_2\text{O} + \text{CH}_3\text{NH}_2 \longrightarrow \underset{\color{#467abf}{\text{N-methylethanamide}}}{\text{CH}_3\text{CONHCH}_3} +~\text{CH}_3\text{COOH}, \text{CH}_3\text{COOH} + \text{CH}_3\text{NH}_2 \longrightarrow \underset{\color{#467abf}{\text{methylammonium ethanoate}}}{\text{CH}_3\text{COO}^-{}^+\text{NH}_3\text{CH}_3}, (\text{CH}_3\text{CO})_2\text{O} + 2\text{CH}_3\text{NH}_2 \longrightarrow \text{CH}_3\text{CONHCH}_3 + \text{CH}_3\text{COO}^-{}^+\text{NH}_3\text{CH}_3, \text{CH}_3\text{COCl} + 2\text{CH}_3\text{NH}_2 \longrightarrow \text{CH}_3\text{CONHCH}_3 + {\text{CH}_3\text{NH}_3}^+\text{Cl}^-, (\text{CH}_3\text{CO})_2\text{O} + 2\text{C}_6\text{H}_5\text{NH}_2 \longrightarrow \text{CH}_3\text{CONHC}_6\text{H}_5 + \text{CH}_3\text{COO}^-{}^+\text{NH}_3\text{C}_6\text{H}_5. In the first: If you compare this with the acyl chloride equation, you can see that the only difference is that ethanoic acid is produced as the second product of the reaction rather than hydrogen chloride. Comparing the structures of ammonia and primary amines. In the reaction between ethanoic anhydride and ammonia, the amide formed is called ethanamide. If you choose to follow the link, use the BACK button (or the HISTORY file or GO menu) on your browser to return to this page. in each case, you initially get hydrogen chloride gas - the hydrogen coming from the -NH2 group, and the chlorine from the ethanoyl chloride. The "N" simply shows that the substitution is on the nitrogen atom, and not elsewhere in the molecule. There is no essential difference between this reaction and the reaction with methylamine, but I just want to look at the structure of the N-substituted amide formed. It isn't particularly important in the context of the current page. Then the ethanoic acid reacts with excess ammonia or amine to give a salt â this time an ethanoate. The initial equation would be: The first product this time is called an N-substituted amide. Acetic anhydride reacts with ammonia … So in the first instance you get ethanoic acid and an organic compound called an amide. We'll take methylamine as typical of primary amines where the -NH2 is attached to an alkyl group. . The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. You can write the formula of phenylamine as C6H5NH2. These reactions are considered together because their chemistry is so similar. This particular compound is N-methylethanamide. If ammonia is basic and forms a salt with the ethanoic acid, excess methylamine will do exactly the same thing. There is also a great similarity between acid anhydrides and acyl chlorides (acid chlorides) as far as these reactions are concerned. . There is no essential difference between this reaction and the reaction with methylamine, but I just want to look at the structure of the N-substituted amide formed. The hydrogen is being replaced by an ethanoyl group, CH3CO-. and you can combine all this together to give one overall equation: You need to follow this through really carefully, because the two products of the reaction overall can look confusingly similar. The equation would normally be written: You can think of primary amines as just being modified ammonia. Have questions or comments? Looking at it this way, notice that one of the hydrogens of the -NH2 group has been replaced by an acyl group - an alkyl group attached to a carbon-oxygen double bond. In a primary amine, it is attached to an alkyl group (shown by "R" in the diagram below) or a benzene ring. All you need to know is that at each corner of the hexagon there is a carbon atom, together with a hydrogen atom apart from where the -NH2 group is attached. The reaction happens in two stages: So in each case, you initially get hydrogen chloride gas â the hydrogen coming from the -NH2 group, and the chlorine from the ethanoyl chloride. Then the ethanoic acid reacts with excess ammonia or amine to give a salt - this time an ethanoate. Acid anhydrides aren't so violently reactive as acyl chlorides, and the reactions normally need heating. Amides contain the group -CONH2. Legal. Looking at it this way, notice that one of the hydrogens of the -NH2 group has been replaced by an acyl group â an alkyl group attached to a carbon-oxygen double bond. The first product this time is called an N-substituted amide. So the second stage of the reaction is: Ethanoic anhydride is the only one you are likely to come across for UK A level purposes. We'll take ethanoyl chloride as typical of the acyl chlorides. Its old name is aniline. We'll take ethanoyl chloride as typical of the acyl chlorides. In phenylamine, there isn't anything else attached to the ring as well. Amides contain the group -CONH2. The hydrogen is being replaced by an ethanoyl group, CH3CO-. Because the formula is much easier, it helps to start with the acyl chlorides. Note: If you aren't sure about using this symbol for a benzene ring, you could follow this link to find out all about it. These reactions are considered together because their chemistry is so similar. The salt is called methylammonium ethanoate. So in the first instance you get ethanoic acid and an organic compound called an amide. The reactions are slower. . Amides contain the group -CONH 2. The reactions are slower. This reaction can sometimes look (even more!) Acid anhydrides aren't so violently reactive as acyl chlorides, and the reactions normally need heating. This particular compound is N-methylethanamide. For more information contact us at
[email protected] or check out our status page at https://status.libretexts.org. So the second stage of the reaction is: Ethanoic anhydride is the only one you are likely to come across for UK A-level purposes. If you compare the structure with the amide produced in the reaction with ammonia, the only difference is that one of the hydrogens on the nitrogen has been substituted for a methyl group. Note: The colour coding in these equations is to try to help you to see where everything ends up and where it came from, and to enable you to compare the two reactions more easily. chemistry. . \[ CH_3COOH + XNH_2 \longrightarrow CH_3COO^- + {^+}NH_3X \]. In the reaction between ethanoic anhydride and ammonia, the amide formed is called ethanamide. This is more usually (and more easily!) C H 3 C O N H 2 B. . Everything left over just gets joined together. There is also a great similarity between acid anhydrides and acyl chlorides (acid chlorides) as far as these reactions are concerned. You can write the formula of phenylamine as C6H5NH2. Initially, ethanoic acid is formed as the second product rather than hydrogen chloride gas. You will need to use the BACK BUTTON on your browser to come back here afterwards. This looks more difficult than the acyl chloride case because of the way the salt is written. The corresponding reaction with an acyl chloride is: \[ CH_3OCl + 2CH_3NH_2 \longrightarrow CH_3CONHCH_3 + CH_3NH_3^+ \, Cl^- \]. Again, the reaction happens in two stages. This looks more difficult than the acyl chloride case because of the way the salt is written. We'll take ethanoyl chloride as typical of the acyl chlorides. . We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. So in the first instance you get ethanoic acid and an organic compound called an amide. Because the formula is much easier, it helps to start with the acyl chlorides. The corresponding reaction with an acyl chloride is: In the ethanoate case, that makes it easier to draw the structure of the similar positive ion in the amine equations below. Taking a general case of a reaction between ethanoyl chloride and a compound XNH2 (where X is hydrogen, or an alkyl group, or a benzene ring). Amides contain the group -CONH 2. The second stage of the reaction involves the formation of an ethanoate rather than a chloride. This page looks at the reactions of acid anhydrides with ammonia and with primary amines. Click hereto get an answer to your question ️ Acetic anhydride and ammonia gives the product : LEARNING APP; ANSWR; CODR; XPLOR; SCHOOL OS; answr. It is just like ammonium ethanoate, except that one of the hydrogens has been replaced by a methyl group. It is just like ammonium ethanoate, except that one of the hydrogens has been replaced by a methyl group. You can say that the phenylamine has been acylated or has undergone acylation. Concentrate on these similarities as you go through this page because it should help you to remember. The corresponding reaction with an acyl chloride is: Note: There isn't anything difficult involved in the fact that I have moved the position of the positive charge in the ammonium ion in this equation compared with the previous one.In each case I have placed it as close as possible to the negative charge in the ethanoate ion or chloride ion. If ammonia is basic and forms a salt with the ethanoic acid, excess methylamine will do exactly the same thing. It is likely to take you some time, though, and you may have to visit several other pages as well. Its old name is aniline. We'll take methylamine as typical of primary amines where the -NH2 is attached to an alkyl group.