| 摘要 |
<p>1,142,300. Nitrophenols. FRANCE, ARMED FORCES, MINISTER OF. 4 Aug., 1966 [6 Aug., 1965], No. 35053/66. Heading C2C. In a process for the preparation of substituted 4,6-dinitrophenols of the formula in which R 1 represents an alkyl radical containing at least 2 carbon atoms or a substituted or unsubstituted cycloalkyl, aralkyl or aryl radical and R 2 represents a hydrogen atom or an alkyl radical, a phenol of the formula in which R 1 and R 2 have the above meanings is subjected to direct nitration with aqueous dilute nitric acid alone having a concentration below 70% by weight at a temperature above 10‹ C. but below or at the boiling point of the reaction medium, an excess of nitric acid being employed so that the final residual acid titre after nitration is at least 4% by weight of the total acid plus water content of the reaction mixture. The process may be carried out continuously, the two reactants being passed into a centrifugal pump, Venturi tube, cyclone or emulsifier. In examples the 4,6-dinitro derivatives of oethyl-, o-isopropyl-, o-tert-butyl-, o-sec-butyl-, o-phenyl, o-cyclo-hexyl-, o-benzyl-, o-(p-chloro)- benzyl-, and 2-tert-butyl-5-methyl phenols are prepared. In some examples the starting material phenol is emulsified with water.</p> |
