摘要
通过沉淀、老化、过虑、洗涤、干燥、浸渍和焙烧等过程 ,从TiCl4和H2 SO4制备了SO2 -4/TiO2 固体超强酸 ;用Hammett指示剂法和吡啶吸附的FT -IR光谱法测定了其酸强度和酸中心类型 ;以脂肪酸和脂肪醇为探针反应 ,研究了催化剂预处理温度对催化性能及反应物分子结构对酯化反应的影响。研究结果表明 ,当预处理温度在4 2 5～ 5 75℃范围内 ,SO2 -4/TiO2 催化剂体系可以形成固体超强酸 ,同时表面上存在Lewis酸中心和Bronsted酸中心 ,并且Lewis酸中心和Bronsted酸中心可以相互转化 ;SO2 -4/TiO2 在酯化反应中表现出良好的催化活性 ,但随着脂肪酸和脂肪醇的碳原子数增加或支链度增大 。
SO 2- 4/Tio 2 solid superacid catalysts was made from TiCl 4 and H 2SO 4 by precipitation, aging, filtering, washing,maceration and calcination processes whose acidity was determined by Hammett indicators and FT-IR spectroscopy of pyridine adsorption methods. The effects of the pre-treatment temperatures on the catalytic properties and reactants molecular on the esterificatoin were studied by using esterification of aliphatic acids with aliphatic alcohols as a probe reaction. It shows that solid superacid is formed in the SO 2- 4/TiO 2 system in the 425～575 ℃ temperatures range and their surface had Lewis and Bronsted acidic centers as well as Lewis acidic center and Bronsted acidic center might interchange; SO 2- 4/TiO 2 solid superacid catalyst has high catalytic activities in the esterification of aliphatic acids with aliphatic alcohols, The conversion is reduced as the carbon atomic numbers or the branch-degree of aliphatic alcohols and aliphatic acids increased.
出处
《石油化工高等学校学报》
CAS
2002年第4期34-36,共3页
Journal of Petrochemical Universities
