Organic 2 Review Problem 380

Organic 2 Review Problem 380 - /O CO H 2 C-CO and C 6 H 4 ^...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
364 PRACTICAL ORGANIC CHEMISTRY phenol and fuse very gently. A green fluorescent solution is produced on the addition of NaOH solution. Section 17. (A) Acid chlorides. R-COCl. (cf. Tables, pp. 543-545) (B) Acid anhydrides. R CO O CO R (A) ACID CHLORIDES. Acetyl chloride; benzoyl chloride (and substituted benzoyl chlorides). (B) ACID ANHYDRIDES. Acetic anhydride, succinic anhy- dride; phthalic anhydride (and substituted derivatives). (A) ACID CHLORIDES. Physical properties. Colourless liquids when pure, benzoyl chloride, C 8 H 6 COCl, is frequently pale yellow. Acetyl chloride, CH 3 COCl, has a pungent odour, fumes in moist air and is immediately hydrolysed by cold water. Benzoyl chloride also has a pungent odour, is lachry- matory, and is hydrolysed only slowly by cold water, in which it is insoluble. (B) ACID ANHYDRIDES. Physical properties. Acetic anhydride, (CH 3 CO) 2 O, is a colourless liquid with a sharp pungent odour, decomposed slowly by water, in which it is only slightly soluble. H 2 C-CO Succinic anhydride and phthalic anhydride (of structure
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: /O CO H 2 C-CO and C 6 H 4 ^ ^)O respectively) are both colourless crystalline solids C0 almost insoluble in cold water. The chemical reactions of the acid chlorides and anhydrides are so closely parallel that they are considered together. GENERAL REACTIONS. 1. Acid chlorides (but not acid anhydrides) precipitate silver chloride on treatment with aqueous AgNO 8 acidified with HNO 3 . 2. Hydrolysed by water or (more rapidly) by alkalis to corres-ponding carboxylic acid or salt. 3. Form esters with alcohols. 4. Acid chlorides, and some anhydrides, condense with aniline to give anilides. 5. Acid chlorides and anhydrides give hydroxamic acids with R-COCl+H-NHOH->R-CO-NH-OH-fHCl (R-CO) 2 O+H-NHOH-^2R-CO-NH-OH+H 2 O hydroxylamine (see p. 332). N.B. In all these reactions acetyl chloride reacts with much greater vigour than the other compounds, and accordingly tests with this substance must be carried out with extreme care....
View Full Document

Ask a homework question - tutors are online