一种高性能的苯酚羟基化用复合氧化物催化剂

用Hβ沸石对复合氧化物进行修饰和改性,制得一种高性能苯酚羟基化用复合氧化物催化剂Fe Hβ80〔w(Hβ) =7%〕。以Fe Hβ80做催化剂,对羟基化反应工艺条件进行了优化,优化的反应工艺条件为:反应温度65~70℃,反应时间0 25~0 5h,m(苯酚) /m(催化剂) =294~883,n(苯酚) /n(H2O2 ) =3 00~5 78,m(苯酚) /m(水) =0 43~0 91。以Fe Hβ80作催化剂,去离子水为溶剂,反应温度65℃,反应时间30min,苯酚5 3g,m(苯酚) /m(催化剂) =294,n(苯酚) /n(H2O2 ) =3 00,溶剂水10 0g,反应结果表明,羟基化反应诱导期不到1min,苯酚转化率22 3%,苯二酚选择性91 9%,过氧化氢有效利用率62 1%。与Fe Cu Sn Zn O/γAl2O3、Fe Mg O/γAl2O3 和TS分子筛等典型苯酚羟基化用催化剂相比较,由于Hβ沸石能为复合氧化物催化剂提供合适的酸性中心,从而缩短了苯酚羟基化反应诱导期,提高了催化活性和目标产物选择性,降低了过氧化氢在反应器中积累所带来的风险。Fe Hβ80催化剂用量仅为TS分子筛的1 /29 4(质量比), 但羟基化反应诱导期仅1min(TS分子筛为120min),证明Fe Hβ80是一种高性能的苯酚羟基化用催化剂。

A High Performance Catalyst of Composite Oxides for Hydroxylation of Phenol

A high performance catalyst (Fe-Hβ-80) for hydroxylation of phenol was prepared with the iron-based composite oxides modified by Hβ zeolite〔n(Si)/n(At)=80,w (Hβ)=7.0%〕.Because of the interposition of Hβ zeolite with suitable acid sites into the composite oxides,the activities of the catalyst was enhanced,and the utilizing efficiency of hydrogen peroxide and the selectivity of goal products were also improved greatly,while the operation risk of hydroxylation reactor was reduced with the lowering of hydrogen peroxide concentration in the hydroxylation reactor due to short induction period.The reaction conditions were optimized as reaction temperature 65～70 ℃,reaction time 0.25～0.50 h,m(phenol)/m(catalyst) 294～882,n(phenol)/n(hydrogen peroxide) 0.23～0.33 and m(phenol)/m(water) 0.43～0.91.Thus,using Fe-Hβ-80 as catalyst with 5.3 g phenol,m(phenol)/m(catalyst)=294,n(phenol)/n(hydrogen peroxide)=3.0,and m(phenol)/m(water)=0.5,reacting at 65 ℃,for 0.5 h conversion of phenol and selectivity for dihydroxybenzenes were 22.3% and 91.9% respectively.The induction period of hydroxylation is less than 1 min.Finally,the high performance catalyst Fe-Hβ-80 was compared with those typical catalysts such as Fe-Mg-O/γ-Al_2O_3,Fe-Cu-Sn-Zn-O/γ-Al_2O_3 and TS molecular sieves etc.