固体超强酸催化剂S_2O_8^(2-)/ZrO_2-M_xO_y(M=Al,Ti,Cr,Mn,Fe)的研究

Study of Solid Superacid CatalystsS_2O_8^(2-)/ZrO_2-M_xO_y(M=Al,Ti,Cr,Mn,Fe)

以ZrOCl2 ·8H2 O、AlCl3、Ti(SO4 ) 2 、CrCl3、MnSO4 、FeCl3为原料 ,通过NH3·H2 O共沉淀、c〔(NH4 ) 2 S2 O8〕 =0 50mol/L浸渍 ,60 0℃焙烧 3 0h制得S2 O82 - /ZrO2 MxOy(M =Al,Ti,Cr,Mn,Fe)系列固体超强酸催化剂 ,用XRD、EBT、流动Hammett指示剂法和化学分析法测定了其晶型结构、比表面积、酸强度和硫含量 ,用乙酸和正丁醇的酯化反应研究了样品的催化活性。结果表明 :S2 O82 - /ZrO2 MxOy中ZrO2 主要以四方晶相 (tetragonalphase)存在 ,MxOy高度分散 ,样品的比表面积 89 0～ 1 1 4 5m2 / g,酸强度H0 <- 1 4 52 ,w(S) =3 1 6 %～ 5 1 2 %。样品对酯化反应表现出较高的催化活性 ,在反应条件为 :0 1 7mol乙酸、0 33mol正丁醇、1 0g催化剂、8 0mL环己烷 (带水剂 ) ,回流温度反应 2 0h ,乙酸的转化率可达 88 5 %～ 97 1 % ,在同样反应条件下 ,没有催化剂时乙酸的转化率仅为 2 9 6 %。催化剂易回收而且能重复使用 。

A series of new type solid superacid catalysts S 2O 8 2- /ZrO 2 M x O y (M=Al,Ti,Cr,Mn,Fe) were prepared from ZrOCl 2·8H 2O,AlCl 3,Ti(SO 4) 2,CrCl 3,MnSO 4 and FeCl 3 as raw materials by NH 3·H 2O coprecipitation,0 50 mol·L -1 (NH 4) 2S 2O 8 maceration and calcination at 600 ℃ for 3 0 h.Their crystal structure,surface area,acid strength and sulfur content were determined by means of XRD,EBT,flow Hammert indicator method and chemical analysis.The catalytic activity was studied by esterification reaction of acetic acid and n butanol.The results showed that ZrO 2 in S 2O 8 2- /ZrO 2 M x O y existed mainly as tetragonal phase,M xO y in S 2O 8 2- /ZrO 2 M x O y was highly dispersed,the surface area of the catalysts was 89 0 m 2/g-114 5 m 2/g,the acid strength of the catalysts was H 0<-14 52,and the sulfur content of the catalysts was 3 16%-5 12%.The catalysts had high activity in the esterification reaction.Thus,0 17 mol acetic acid, 0 33 mol n butanol,1 0 g catalyst and 8 mLcyclohexane(as water entrainer) reacted at the reflux temperature for 2 0 h,the conversion of acetic acid could reach 88 5%-97 1%,while under the same reaction conditions,the conversion of acetic acid was only 29 6% without the catalyst.The catalysts can be easily recovered and reused,and have very good stability of activity.