NI_CO_B非晶态合金催化剂用于氯代硝基苯液相加氢制氯代苯胺_严新焕

文章编号:0253-9837(2006)02-0119-05

研究论文:119～123

收稿日期:2005-05-13.　第一作者:严新焕,男,1964年生,教授.

联系人:严新焕.Tel /Fax :(0571)88320791;E -mail :w hh97@sina .com .基金项目:国家自然科学基金(20276071)和浙江省重大自然科学基金(ZE0102)资助项目.

Ni -Co -B 非晶态合金催化剂用于氯代硝基苯

液相加氢制氯代苯胺

严新焕,　孙军庆,　徐颖华,　杨建峰

(浙江工业大学绿色化学合成技术国家重点实验室培育基地,浙江杭州310032)

摘要:用化学还原法制备了N i -Co -B 非晶态合金催化剂,并采用透射电子显微镜、扫描电子显微镜、选区电子衍射、X 射线衍

射、X 射线能谱和差热-热重分析等表征手段研究了催化剂的非晶性质和原子组成等.将此催化剂用于邻氯硝基苯和3,4-二氯硝基苯的液相催化加氢反应,结果表明,当Co /(Co +Ni )=0.5(摩尔比)时,N i -Co -B 催化剂具有较好的加氢性能和较高的抑制脱卤性能.在不加脱卤抑制剂的情况下,两种氯代硝基苯的转化率均接近100%,脱卤率分别为1.12%和0.42%,优于使用Ni -B 和Co -B 非晶态合金催化剂时的结果.还讨论了将Co 引入到Ni -B 非晶态合金催化剂时对其性能的影响.关键词:镍;钴;硼;非晶态合金;邻氯硝基苯;3,4-二氯硝基苯;催化加氢;氯代苯胺中图分类号:O643 文献标识码:A

Liquid -Phase Hydrogenation of Chloronitrobenzene to Chloroaniline

over Ni -Co -B Amorphous Alloy Catalyst

YAN Xinhuan ＊,SUN Junqing ,XU Yinghua ,YANG Jianfeng

(State Key Laboratory Breeding Bas e of Green Chemistry -Synthesis Technology ,Zhejiang University of Technolo gy ,Hangzhou 310032,Z hejiang ,China )

A bstract :The Ni -Co -

B bimetallic amorphous alloy with Co /(Co +Ni )molar ratio varying from 0to 1w as pre -pared by chemical reductio n of Ni (NO 3)2and Co (NO 3)2with KBH 4in solution .Its amorphous structure was verified by X -ray pow der diffraction and selected area electron diffraction .The thermostability of the amorphous alloy w as characterized by thermog ravimetry -differential thermal analysis .Scanning electron microscopy and transmission electro n microscopy w ere used to determine its morphology and particle size .The Ni -Co -B amor -phous catalyst w ith a Co /(Co +Ni )molar ratio of 0.5exhibits a much hig her activity and selectivity than the Ni -B and Co -B catalysts in the liquid -phase hydrogenation of chloronitrobenze to chloroaniline .The m aximum conversion of both o -chloronitrobenzene and 3,4-dichloronitrobenzene reaches 99.9%,w hereas the dechlorina -tion of chlo roaniline w as 1.12%and 0.42%,respectively ,show ing a good po tential for industrial applications .The higher activity and selectivity of the Ni -Co -B catalyst can be attributed to the electron donation from the al -loying B and metallic Co to the metallic Ni .Following this ,the B and Co atoms become electron -deficient w hereas the Ni atom becomes electro n -enriched ,w hich can activate the N =O bond ,inhibit the hydrodechlori -nation of chloronitrobenzene ,and increase the thermostability of the amo rphous alloy .Key words :nickel ;cobalt ;boron ;amorphous alloy ;o -chlo ronitrobenzene ;3,4-dichlo ronitrobenzene ;catalytic hydrogenation ;chloroaniline 卤代芳胺是重要的基础化工原料与有机中间体,在医药、农药和染料等领域有着广泛的用途,其

生产方法主要是芳香硝基化合物的还原,包括铁粉还原法、硫化碱还原法和催化加氢还原法等.其中,

第27卷第2期催　化　学　报

2006年2月Vol .27No .2

Chinese Journal of Catalysis

F ebruary 2006