如何把苯环上的硝基还原成氨基.docx

如何把苯环上的硝基还原成氨基？1.最简单常见的方法是铁酸还原法。原料溶于50%左右的乙醇中，加入还原铁粉，滴加盐酸或醋酸，加热反应，然后加入氨水或氢氧化钠等碱调PH值到碱性，萃取或水蒸气蒸馏得到产品。缺点是后处理很麻烦，生成的铁泥不易过滤，且废渣污染环境。也有用氯化铵作为酸的还有用金属锌作为还原剂的2.催化氢化。原料溶于溶剂，用Ranry镍，钯碳，铂碳等为催化剂，通入氢气作为还原剂。（反应结束过滤掉钯炭就可以了，最简单，工业生产，有时需要加些压力。）3.硫化物为还原剂的。用硫化钠或二硫化钠作为还原剂。在苯环上有两个硝基时，可以通过控制还原剂的用量，来选择性地之还原其中一个硝基成氨基，令一个硝基不变。（硫酸亚铁加氨水试过可以）【加保险粉（连二亚硫酸钠）,甲醇和水作溶剂，室温搅拌，反应后，过滤下，就好了】4.金属的氢化盐。比如四氢铝锂，硼氢化钠等。但是比较昂贵。5.特殊催化剂催化下，用一氧化碳还原。不仅需要Ru3(CO)9(TPPTS)3这样的特殊催化剂，还需加入十六烷基三甲基溴化铵为相转移催化剂。然后通入一氧化碳。6.苯环上硝基还原成氨基，用的是氯化亚锡和浓盐酸，没有有机溶剂，把硝基化合物研碎，最好成粉状，加入氯化亚锡，盐酸加热反应，一个半小时后处理。（产率挺高，可以用非均相反应，效果也不错，做过）7.锌粉加氢氧化钠（很好，至少一些钯碳无法还原的，它可以）8.用铁粉在盐类电解质（低铁盐和氯化铵等）的水溶液中还原。可将芳香族硝基、脂肪族硝基或其他含氧氮功能基（如亚硝基、羟胺等）还原成相应的氨基。（一般对卤素、烯基等基团无影响，可用于选择性还原。还原用的铁粉应选用含硅的铸铁粉，熟铁粉、钢粉及化学纯度的铁粉效果差。实验室）9.SnCl2还原，乙醇溶剂，80度回流，不加盐酸也行。反应完加40%的NaOH，然后用乙酸乙酯萃取。丙酮、水，醋酸铵，TiCl3。室温搅拌，反应完，过滤，旋干10.硝基还原成氨基后，怎么保证不被氧化？1）过滤的时候，用氮气压滤，浓缩的时候在放真空时充入氮气，注意避光2）要想不氧化可以试试用酸使其成盐，成盐就稳定多了3）用保护基也可以，保护胺最常用叔丁氧羰基(BOC)含有硝基苯基的化合物中硝基还原成氨基的方法本发明公开了一种含有硝基苯基的化合物中硝基还原成氨基的方法，由下述步骤组成：（）分别称取硫化钠、硫代硫酸钠，用水完全溶解；（）称取硝基化合物加入适量有机溶剂溶解；（）将溶解的硫化钠水溶液、硫代硫酸钠水溶液加入到步骤（）制备的溶液中；（）间接加热，回流，搅拌，反应小时天，点硅胶板监测反应，与原料点比较有不同，停止加热，旋干有机溶剂，抽滤，滤饼反复用水淋洗至水溶液基本无色，真空干燥后即制得氨基化合物；本发明操作安全简便、还原介质主要为水或常用溶剂，溶剂可回收、常压既可顺利还原，在产物的后处理只需水洗干燥即可。如何把苯环上面的氨基氧化成硝基？1.用过量的双氧水来氧化（氨基苯通常是可溶于水的，氧化之后的硝基苯是与水分层的很好分离经济实惠还易操作效果非常好,有做过的）2.用过硫酸盐氧化（这样的收率不是很高）3.低温盐酸，亚硝酸钠重氮化就OKProcedureThirty-four grams (0.25 mole) of p-nitroaniline is dissolved in 110 cc. of fluoboric acid solution (Note 1) in a 400-cc. beaker. The beaker is placed in an ice bath and the solution stirred with an efficient stirrer. A cold solution of 17 g. (0.25 mole) of sodium nitrite in 34 cc. of water is added dropwise. When the addition is complete, the mixture is stirred for a few minutes and filtered by suction on a sintered glass filter. The solid diazonium fluoborate is washed once with 2530 cc. of cold fluoboric acid, twice with 95 per cent alcohol, and several times with ether (Note 2). The product weighs 5659 g. (9599 per cent of the theoretical amount).Two hundred grams of sodium nitrite is dissolved in 400 cc. of water in a 2-l. beaker, and 40 g. of copper powder is added (Note 3). The mixture is stirred with an efficient stirrer (Note 4), and a suspension of the p-nitrophenyldiazonium fluoborate in 200 cc. of water is added slowly. Much frothing occurs, and 45 cc. of ether is added from time to time to break the foam. The reaction is complete when all the diazonium compound has been added. The product is filtered with suction, washed several times with water, twice with dilute sodium hydroxide solution, and again with water. The solid is dried in an oven at 110, powdered, and extracted with 300-cc., 200-cc., and 150-cc. portions of boiling benzene. The benzene is evaporated on a water bath, and the residue is crystallized from 120150 cc. of boiling glacial acetic acid. The resulting reddish yellow crystals, melting at 172173, weigh 2834.5 g. (6782 per cent yield) (Note 5). Recrystallization from alcohol yields pale yellow crystals melting at 173.2,6-DICHLORONITROBENZENEBenzene, 1,3-dichloro-2-nitro-ProcedureCaution! The preparation and handling of peroxytrifluoroacetic acid should be carried out behind a safety screen. Precautions to be observed with 90% hydrogen peroxide are described in (Note 3) and should be carefully followed.A 300-ml. three-necked flask equipped with a Trubore stirrer, dropping funnel, and reflux condenser protected with a calcium chloride drying tube is charged with 100 ml. of methylene chloride (Note 1). To this solvent is added without stirring 5.4 ml. (0.20 mole) of 90% hydrogen peroxide (Note 2), (Note 3), (Note 4), (Note 5). The hydrogen peroxide is not miscible with the solvent and separates as the lower layer at the bottom of the flask. The flask is then cooled in an ice bath, and the stirrer is started. To this cold solution over a 20-minute period is added 34.0 ml. (0.24 mole) of trifluoroacetic anhydride. After addition is complete, the ice bath is removed and the solution is stirred at room temperature for 30 minutes.A solution is then prepared from 8.1 g. (0.05 mole) of 2,6-dichloroaniline (Note 6) and 80 ml. of methylene chloride. This solution is added dropwise over a 30-minute period to the previously prepared peroxytrifluoroacetic acid reagent (Note 7). During this addition the exothermic reaction causes the mixture to reflux. After addition is complete, the mixture is heated under reflux for 1 hour. It is then cooled and poured into 150 ml. of cold water. The organic layer is separated, washed with 100 ml. of water, with two 100-ml. portions of 10% sodium carbonate solution (Note 8), and finally with 50 ml. of water. The organic extract is treated with activated charcoal and anhydrous magnesium sulfate. After standing overnight, the volatile solvent is removed at aspirator pressure with the aid of a warm water bath. There is obtained 8.68.8 g. (8992%) of ye