The Catalist Synthesis Of Butyl P-hydroxybenzoate And Optimizing Of Manufacturing Technique

Comparing with some of traditional preservative,butyl p-hydroxybenzoate has many of apparent advantage such as low toxicity,excellent property of anticorrosion,low irritating and so on.As a kind of important new type preservative,butyl p-hydroxybenzoate was extensive used in many fields such as daily using chemical,food and fodder.Basing on butyl p-hydroxybenzoate remarkable economic benefit,more and more researchers paid attention to research the manufacturing technique of butyl p-hydroxybenzoate.In this paper,we synthesized many types of catalyst.For instance,porous carbon loading with KHSO₄,porous carbon loading with heteropolyacid and SO₄^2-/TiO₂ solid super acid were prepared,and there were used as catalist to catalyze production butyl p-hydroxybenzoate.（1）In the second section of this paper,we prepared ideal porous carbon as carrier by a simple calcine method.Subsequently,the KHSO₄ was loaded to porous carbon surface to construct catalyst of KHSO₄/C,and processed a series of characterization analysis.In the next,butyl p-hydroxybenzoate was synthesized by using KHSO₄/C as catalyst,pare hydroxybenzoic acid（PHBA）and n-butyl alcohol as raw material.We also researched the influence factors of acid conversion percent and product yield by the molar ratio of alcohol to acid,concentration of KHSO₄ solution,catalyst dosage and reaction time.We can clearly seen from the result that the acid conversion percent and product yield can reach 97.6%and 88.6%when the condition of reaction is that the catalyst was immersed in KHSO₄ solution with 12%concentration,the molar ratio of alcohol to acid is 2,the catalyst dosage is 3.5%of raw material weight and reaction for 3 h.We also researched the property of catalyst for recycle using,the result demonstrate that KHSO₄/C have poor property of recycle,and the product yield decreased 19.3%after cycling using for 6 times.（2）In the third section,we prepared porous carbon by the same method as before,and synthesized heteropolyacid/porous carbon catalyst by loading heteropolyacid in porous carbon surface.Using it as catalyst and PHBA and n-butyl alcohol as raw material,we synthesized butyl p-hydroxybenzoate,and we also researched the relationship between product yield with types of heteropolyacid.We found that it have an obvious distinction of product yield when different heteropolyacid was used as catalyst,and the catalyst activity of heteropolyacid is H₃PW₁₂O₄₀>H₃SiW₁₂O₄₀>H₃PMo₁₂O₄₀.In the next,we used H₃PW₁₂O₄₀/porous carbon as catalyst to research product yield influence by other reaction condition such as the molar ratio of alcohol to acid,capacity of heteropolyacid,catalyst dosage and reaction time.We found that the reaction have higher product yield when the reaction condition are:the molar ratio of alcohol to acid is 2,the capacity of heteropolyacid is 30%,the catalyst dosage is3.5%of raw material weight and reaction for 3 h.（4）In the forth section,we fabricated SO₄^2-/TiO₂ solid super acid,and characterized it by many of technologies such as XRD,SEM and infrared spectroscope.Using SO₄^2-/TiO₂ solid super acid as catalyst and PHBA and n-butyl alcohol as raw material,we synthesized butyl p-hydroxybenzoate.We also researched relationship between product yield of butyl p-hydroxybenzoate with the molar ratio of alcohol to acid,the claimed temperature of SO₄^2-/TiO₂ solid super acid and reaction time and catalyst dosage.The result prove that when the ratio of alcohol to acid is 2,the catalyst was claimed in 500℃and the weight of catalyst is 2.5%of raw material,the reaction time is 2.5h,we can reach higher product yield and acid conversation rate that is 88.8%and 97.4%,respectively.We can clearly seen that the SO₄^2-/TiO₂ solid super acid catalyst has excellent property of recycle,and the product yield drop 11.6%after recycle for 6 times.