Preparation Of SO₄^2-/ZrO₂-MO₃ (M=Mo, W) Solid Acid And Catalytic Synthesis Of N-Butyl Acetate

Esterifications catalyzed by acid catalysts have been paid more attention. Liquid acid catalysts,such as H₂SO₄ is often used in the conventional esterification processing technology.Nonetheless,this liquid acid is unpopular because of its corrosiveness,producing large amount of by-products.For these reasons,there is a genuine desire to develop environmental friendly and acceptable solid catalysts.With the discovery of its strong acidity,sulfated zirconia has attracted much attention as a potential solid acid catalyst.Although SO₄^2-/ZrO₂ displays good initial activity for catalyzing esterification,the fast deactivation at high temperature prevents its application in industry.So mixing it with other oxides can get over these disadvantages.In this paper, SO₄^2-/ZrO₂-MoO₃ and SO₄^2-/ZrO₂-MoO₃-WO₃ have been prepared.The structures,morphology,textural of the catalysts were systematically characterized by XRD,FT-IR,DTA.SEM and TEM.Influence of doped amount of oxide and calcining temperature on crystalline temperature and crystal transformation temperature have been investigated.The results indicated that the introduction of MoO₃ markedly inhibited the phase transformation from tetragonal ZrO₂ to monoclinic ZrO₂ and the cooperation of WO₃ and MoO₃ can greatly improved the thermal stability.The SEM results suggested that the surface of ZrO₂ exhibits MoO₃ particles of a column shape.This column structure can improve the sintering temperature and reduce grain-growth rate by inserting into the surface of the zirconia particle, which reduces the mobility of defects on the grain surface.The mechanism was discussed that synthesis of n-butyl acetate with self-made solid acid,through the method of changing factor to search for the conditions of catalytic reaction.The best conditions were confirmed that:the quantity of SZMW-0.03-650 catalyst is 0.3g,and the yield of ester reaches 84.8%in the condition that the reaction time is 1.5h and the quantity of acid and alcohol are 6.0g and 8.88g.Under the same reaction condition,comparing with other solid acid catalyst, this catalyst had the advantages of high yield of product,easy to recover,better reuse quality,the yield of product was also 70.3%after the catalyst used 5 times.