尿素與苯胺合成n，n39;二苯基脲的清潔生產(chǎn)工藝研究

1、湘潭大學碩士學位論文尿素與苯胺合成N，N'-二苯基脲的清潔生產(chǎn)工藝研究姓名：游志敏申請學位級別：碩士專業(yè)：環(huán)境工程指導教師：戴友芝;李會泉20080519湘潭大學碩士學位論文 IIAbstract N, N'-diphenylurea is an important organic intermediate, which mainly used for the synthesis of sulfa drugs, isoc

2、yanate and other chemicals. The traditional method for the preparation of N, N'-diphenylurea utilizes phosgene as a raw material directly or indirectly, which is toxic, corrosive, expensive, and restricted to employ.

3、 The industrial synthesis of N, N'-diphenylurea from urea and aniline uses water as solvent and hydrochloric acid as catalyst, giving only 40% yield of N, N'-diphenylurea, and dischargeing aniline waste water and

4、 hydrogen chloride waste gas, which are both difficult to be handled. As urea is a cheap material and an important industrial chemical synthesized from CO2, there is high economic and environmental potential in N, N'

5、-diphenylurea synthesis from urea. But how to maximize the utilizing efficiency of raw materials and minimize the quantity of waste need further study. In this dissertation, a process of N, N'-diphenylurea catalytic

6、synthesis from urea and aniline in organic solvents, using neither water nor hydrochloric acid, was investigated. Based on this , a clean process of N, N'-diphenylurea synthesis from urea and aniline without any cata

7、lysts and solvents was developed, the reaction mechanism was also mentioned and proved. The main contents studied and results obtained shows as follow: (1) The synthesis of N, N'-diphenylurea from urea and aniline c

8、atalyzed by various catalysts in a variety of solvents was investigated. It is found that xylene is the optimal solvent, zinc acetate and p-toluenesulfonic acid - lead acetate catalysts are the optimal catalysts. The yie

9、ld of N, N'-diphenylurea reached 94.0% and 92.9% under the optimum reaction condition of temperature 144 , ani ℃ line/urea/xylene ratio 3:1:2 (molar ratio), reaction time 1.5 h, catalyzed by zinc acetate and p-tolu

10、enesulfonic acid - lead acetate, respectively. (2) The clean process of N, N'-diphenylurea synthesis from urea and aniline without any solvents and catalysts was investigated, the various reaction conditions on the y

11、ield of N, N'-diphenylurea were also studied. The results of FT-IR, MS, NMR and UV analysis showed that the product of the developed process was N, N'-diphenylurea with high purity, the yield of N, N'-dipheny

12、lurea reached 92.1% under the optimum reaction condition of temperature 180 , aniline/urea ratio 5:1 (molar ratio), reaction time 1.5 h. ℃(3) Investigation showed that the yield of N, N'-diphenylurea could be furth