| 摘要 |
<p>Terephthalic acid, isophthalic acid or their monomethyl esters are prepd. by oxidising p-xylene, m-xylene or the corresponding methyl esters of toluic acid in a soln. of an alkali metal acetate (pref. 0.1-5 wt.%) in acetic acid, using a catalyst contg. Co and Br at an elevated temp. (pref. 130-150 degrees C) and under a high pressure (pref. 2-6 atm). The alkali metal acetate is Na or K acetate. Immediately after its separation from the reaction mixt., the pdt. is washed with pure and/or aqs. acetic acid at 20-120 degrees C. Gives better molar yields and space time yields of the pdts. The pdts. are obtained in the form of crystals with a good shape and size, and a high purity. Corrosion of the appts. is reduced.</p> |
