M-Bromobenzoyl chloride

Preparation by dealkylation of 3-bromo-4 -ethoxy-benzophenone (SM) with hydrobromic acid (d = 1.49) in boiling acetic acid for 2 days. SM was obtained by action of m-bromobenzoyl chloride with phenetole in carbon disulfide in the presence of aluminium chloride at 55° (80%, m.p. 79°5). -Refer to Chem. Abstr., 17, 3497 (1923) . m.p. 171° Spectra (NA). 

The rates of reaction of substituted benzoyl chlorides with excess methanol at 0°C were measured. The pseudo-first-order rate constant for p-methylbenzoyl chloride is 0.0178mol/lmin and for p-nitrobenzoyl chloride is 0.413 mol/1 min. Calculate the rate constant for m-bromobenzoyl chloride, assuming these two examples give a good correlation [39]. (Of course, in a proper study a larger set of examples would he used to obtain a correlation.)... 

A solution of 8.5 g. (0.04 mole) of p-bromobenzoyl chloride (p. 41) in 10 ml. of benzene is added slowly with vigorous stirring to a mixture of 5 g. of sodium j)eroxide and 50 ml. of ice-cold water. The precipitated white solid is removed by filtration and recrystallized from methanol to give 5.5 g. (71%) of p-bromobenzoyl peroxide, m.p. 143.5 dec. 

Bromobenzoyl chloride [586-75-4] M 219.5, m 36-39 , 39.8 , 41 , b 62 /0.1mm, 104.5 /6mm, 126.4-127.2 /14mm. Check IR of a film to see if OH bands are present. If absent then recrystallise from petroleum ether and dry it in vacuo. If OH bands are weak, then distil it in vacuo and recrystallise if necessary. If OH bands ate very strong, then treat with an equal volume of redistilled SOCI2 reflux for 2 hours, then evaporate excess of SOCI2 and distil the residual oil or low melting solid. Store it in the dark away from moisture. LACHRYMATORY. [Martin Partington J C/jew Soc 1175 1936, Beilstein 9 IV 1023 ]... 

Preparation by demethylation of 4 -bromo-2-fluoro-4-methoxybenzophenone (SM) with 62% aqueous hydrobromic acid in acetic acid at 125°. SM was obtained by Friedel-Crafts acylation of m-fluoroani-sole with p-bromobenzoyl chloride in nitrobenzene in the presence of aluminium chloride [512]. 

---