U. Simpson Stubbs, Jr. and Cyril F. Atkins Morgan State College Baltimore, Maryland
II
h i h e by
CI
Modified Jones Redudor Method
140 g zinc (10 mesh) is stirred with a mixture of 30 ml saturated mercuric chloride solution and 300 ml of 2.5 N HC1 for 5 minutes. The solution is poured off and the amalgam thoroughly washed with distilled water. (Any unused amalgam can be kept under water.) A small plug of glass wool is placed a t the bottom of the Jones reductor tube which is then filled within 15 cm of the top with the prepared zinc amalgam. The reductor is then fitted with a filter flask which is attached to a suction pump. .The stopcock is closed and the amalgam in the reductor is covered with water. Best results were obtained by adding 145 ml of 5 N HzSOIand 10 ml of nitrobenzene to the amalgam in the following manner: The water was drained from the reductor and 15 ml of the acid added with the stopcock partially opened. Small amounts of acid and nitrobenzene were added alternately. The stopcock and the suction were adjusted so as to keep a steady stream of product flowing. This part of the experiment must be carried out in such a way as to make certain that the reaction takes place within the body of the amalgam. Any aniline remaining in the reductor a t the end of the reaction was washed out with 5 N H,S04. The mixture in the filter flask was neutralized with a saturated solution of NaOH, the aniline steam distilled and extracted with ether. The ethereal solution was dried with solid NaOH, the ether distilled off, and the ISee, for example, COLEMAN,GEORGEH., WAWZONEK, boiling point of the residue taken. This residue (aniAND BUCKLES, ROBERTE., "Laboratory Manual of STANLEY, line) boiled a t 184°C. The phenylthiourea of aniline Organic Chemistry," Yrentice-Hall, Ine., New York, 1949, p. 65. was prepared which melted at 154°C. *HAMILTON,LEICESTERF., AND SIMPSON,STEPHENG., We hope both to increase the aniline yield and to "Quantitative Chemical Analysis," 10th ed., The Macmillan Co., New York, 1954, p. 212. apply the method to other compounds. One of the standard experiments in first year organic chemistry is the preparation of aniline by treating nitrobenzene with mossy tin and hydrochloric acid. This method, which is essentially a reduction of nitrobenzene to aniline, is described in a number of organic laboratory manuals.' We present here what we believe to be a more interesting laboratory preparation of aniline. This method also shows students that some inorganic preparations and methods can be utilized in organic preparations. Although the Jones reductor method has been used in previous years as a means of reducing certain inorganic substances, such as the reduction of iron in limonite2 before it is quantitatively determined, we find that by making certain simple modifications in the Jones reductor we can prepare aniline from nitrobenzene. While the yield is only 65-70'%, we believe that this is sufficient as a first-year organic student preparation. We do not intend to imply, however, that total reduction of nitrobenzene is achieved by this method. To separate the unreacted nitrobenzene from the aniline, the product (anilinenitrobenzene mixture) is treated with dilute acid. The aniline reacts with the acid to form a salt leaving the unreacted nitrobenzene, which can then be removed by washing with ether.
Volume 36, Number 12, December 1959
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