叔丁醇在H_(5)PMo_(10)V_(2)O_(40)/SiO_(2)催化剂上吸附的红外光谱研究

Infrared Study of Chemisorption and Conversion of Tert-Butanol on H_(5)PMo_(10)V_(2)O_(40)/SiO_(2) Catalyst

用FTIR研究了叔丁醇在H_(5)PMo_(10)V_(2)O_(4)0/SiO_(2)上的化学吸附和转化,叔丁醇在15℃质子酸的作用下形成(CH_(3))_(3)C^*吸附态,进而转化为类似π-烯丙基结构的吸附态H_(2)C^*=C(CH_(3))=C^*H_(2)和σ-烯丙基吸附态C^*H_(2)C(CH_(3))=CHPph_(3)C<O^*O^*,后者在110℃形成甲基丙烯酸离子吸附态,同时产生表面羟基,叔丁醇的催化转化实验表明,50℃时叔丁醇转化为异丁烯。

The chemisorption and catalytic conversion of tcrt-butanol have been investigated by means of FTIR.At 15℃,chemisorption of tert-butanol has been found to occur on the catalyst surface,the probable chemisorbed state being(CH_(3))_(3)C,π-allyl-like species CH_(2)=C(CH_(3))=CH_(2)andσ-allyl species CH_(2)C(CH_(3))=CH_(2).At 50℃,thisπ-allyl-like species desorbed to give gaseous isobutene.At still higher temperalure(110℃),σ-allyl species was converted into chemisorbed metha-crylate anion,CH_(2)=C(CH_(3))C<O^(*)O^(*)with appearance of surface hydroxyl at 3617cm^(-1).The results are in accord with the experimental fact that the same products are obtained from catalytic conversion of tert-butanol and form isobutcne over H_(5)PMo_(10)V2O_(4)0/SiO_(2)catalyst.