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Description
The structure of acetate anions and the reactivity of acid chlorides examined.
The structure of acetate anions and the reactivity of acid chlorides examined.
| Item code: | S24-; 06 |
|---|---|
| First transmission date: | 25-03-1972 |
| Published: | 1972 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:23 |
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| Publisher: | BBC Open University |
| Keyword(s): | Bonds; Carboxylic frequencies; Derivatives; Infra-red spectrum; Reactivity of acid chlorides; Spectra comparisons |
| Footage description: | Len Haynes, with the infra red spectrum of ethanol, introduces the programme. He shows that the infra-red absorption characteristics of compounds containing the carboxylic acid group differ from the simple combination of characteristics associated with a hydroxyl group. Haynes looks in detail at the absorption spectra of sodium acetate and acetic acid. He proposes that the doublet pattern is explicable if one assumes that two C-O bonds in the salt are identical. Haynes examines an electron density contour diagram for confirmatory evidence that the C-O bonds are identical. R.R. Hill introduces the second part of the programme which examines the reactions of carboxylic acid derivatives. He explains why benzoyl chloride was not sent as part of the home experiment kit and that a less noxious acid chloride, acetyl chloride, will be used for most of the studio experiments. Hill with 3 test tubes of water. He adds an ester (ethyl acetate) to one, acetic anhydrid to the second and acetyl chloride to the third. A vigorous reaction marked by a rise in temperature and production of gas is noted in the third tube. Very little reaction is noted in the other tubes. Hill explains why this is so. Len Haynes explains how amides can be produced from ammonium salts. He uses a mag-board to show the equation for this reaction. Hill demonstrates the reaction by heating commercially available ammonium salt with acetic acid. He then distills the acetamide to further purify it. Hill explains the drawbacks of this method. Hill demonstrates a more versatile method of reaction. He adds a few drops of acetyl chloride to ammonia in water. A vigorous reaction at room temperature results. (The product of the reaction is acetamide). Hill demonstrates the reaction again this time using benzoyl chloride in place of acetyl chloride. The equation for the reaction is shown on the screen. Hill demonstrates a method of producing acid chlorides from thionyl chloride. The equation for the reaction is shown on the screen. Haynes with the equation (on mag-board) which represents a general procedure for making primary amides of this type. Haynes poses the question. Is this equation general enough to make secondary amides? Hill demonstrates such a reaction. To a primary amine, cyclohexylamine, he adds acetyl chloride. There ia a vigorous reaction which produces a white precipitate, the substituted amide. Haynes explains the disadvantages of the above method particularly when used to make tertiary amides. Hill explains the advantages and disadvantages of using esters when producing amides. He uses a molecular model of alcohol to aid his discussion. Hill asks students to write down their observations for the next experiment. To a sample of tertiary butyl alcohol, z-methyl, propan-2-ol, he adds acetyl chloride. He then takes the contents of this tube and adds it to another tube containing water. |
| Master spool number: | 6LT/70312 |
| Production number: | 00521_2164 |
| Videofinder number: | 1723 |
| Available to public: | no |
