Preparation Of Modified CNMS-SO₃H Solid Acid And Its Catalytic Synthesis Of Borneol

Chiral nematic mesoporous silicon(CNMS)has adjustable pore size,large specific surface area,and its surface is covered by a large number of silicon hydroxyl groups.It can be replaced by various functional groups and substituents,so it can provide active sites for the load,so that inorganic metal particles or organic functional groups can well combine with the carrier.CNMS is a new type of porous material with strong potential application.Borneol exists in the essential oils of nature.It is recognized as the world's recognized intermediate for high flavor and spice and pharmaceutical raw materials.It is widely used in the pharmaceutical industry.It has the effect of dispersing stagnation of fire,treating aphtha,removing the eyes and removing eyesight,relieving swelling and relieving pain.Borneol can be obtained from?-pinene in turpentine by esterification saponification reaction.China is a big producer of turpentine with rich output and low price.But the natural borneol has low annual output,high price and short supply.Therefore,the catalytic synthesis of borneol from?-pinene is of great practical significance.In this paper,three kinds of solid acid CNMS-SO₃H?Al₂O₃/CNMS-SO₃H?La³⁺/CNMS-SO₃H catalysts were prepared by modified CNMS,which were first used in the synthesis of borneol by?-pinene.The particular examination contents and achievement are as follows:(1)Synthesis of CNMS-SO₃H solid acid and its catalytic synthesis of BorneolCNMS was prepared by sol-gel method and CNMS-SO₃H solid acid catalyst was prepared by impregnation method.The relationship between the structure and properties of the catalyst was characterized by means of NH₃-TPD,Py-IR,BET,XRD,TG and FT-IR.The best preparation method after catalyst optimization is:sulfuric acid concentration is 1 mol/L,calcination temperature of activated catalyst is 500?.The effects of catalyst dosage,reaction time,the ratio of?-pinene to oxalic acid and reaction temperature on the conversion and yield of borneol were studied.The optimized process shows that the amount of cnms-so3h catalyst is 7%of turpentine,the time is 8 h,the ratio of enoic acid is 1:0.4,and the temperature is 100%The highest yield of borneol was 49.89%and the conversion of?-pinene was 100%.The amount of n-borneol in the product was 4 times of that of isoborneol.The yield of borneol decreased only 2.3%and the conversion of borneol was over 99%after 8 times of reuse of solid acid catalyst,which proved that the catalyst had good catalytic activity and stability.(2)Synthesis of Al₂O₃/CNMS-SO₃H solid acid and its catalytic synthesis of BorneolAl₂O₃/CNMS-SO₃H solid acid catalyst was prepared by impregnation method.The relationship between the structure and properties of the catalyst was characterized by means of NH₃-TPD,Py-IR,BET,XRD,TG and FT-IR.The best preparation method after catalyst optimization is:sulfuric acid concentration is 2 mol/L,calcination temperature of activated catalyst is 500?,m(CNMS):m(Al₂O₃)=2:1.The effects of catalyst dosage,reaction time,the ratio of?-pinene to oxalic acid and reaction temperature on the reaction and the yield of borneol were studied.The results show that the amount of Al₂O₃/CNMS-SO₃H catalyst is 9%of turpentine oil,the time is 9 h,the ratio of enoic acid is 1:0.5,and the temperature is 100 The yield of borneol was 55.20%and the conversion of?-pinene was 100%.The amount of n-borneol in the product was 1.2 times of that of isoborneol.The results showed that the increase of borneol yield was due to the increase of Lewis acid content in Al₂O₃/CNMS-SO₃H catalyst;The yield of borneol decreased only 4.6%and the conversion of borneol was over 99%after six times of reuse of solid acid catalyst,which proved that the catalyst had good catalytic activity and stability.(3)Synthesis of La³⁺/CNMS-SO₃H solid acid and its catalytic synthesis of BorneolLa³⁺/CNMS-SO₃H solid acid catalyst was prepared by impregnation method.The relationship between the structure and properties of the catalyst was characterized by means of NH₃-TPD,Py-IR,BET,XRD,TG and FT-IR.The optimal preparation method of the catalyst is as follows:sulfuric acid concentration is 2 mol/L,La³⁺concentration is 0.021 mol/L,calcination temperature of the activated catalyst is 500?.The effects of catalyst dosage,reaction time,the ratio of?-pinene to oxalic acid and reaction temperature on the reaction and the yield of borneol were studied.The optimized process shows that the amount of La³⁺/CNMS-SO₃H catalyst is 8%of turpentine quality,the time is 9 h,the ratio of enoic acid is 1:0.5,and the temperature is 100 The highest yield of borneol was 40.83%and the conversion of?-pinene was 100%.In the product,borneol was the only borneol but not isoborneol.The results showed that the increase of the yield of borneol was due to the increase of Br?nsted Acid in La³⁺/CNMS-SO₃H catalyst,while the decrease of the total yield of borneol was due to the decrease of the total acid amount;The yield of borneol decreased only 3%and the conversion of borneol was over 99%after six times of reuse of solid acid catalyst,which proved that the catalyst had good catalytic activity and stability.