Preparation Of Functional Ionic Liquids And Research On Catalyzing The Synthesis Of Terpineol From Turpentine

Turpentine is a secondary metabolite of plants,which is cheap and easy to obtain.Its main components are ?-pinene and ?-pinene,of which the content of ?-pinene is more than 90%.Alpha-pinene is a kind of renewable essential oil.It is an indispensable industrial raw material in the fields of food,biopharmaceuticals,perfumes,etc.It can react with a variety of active groups to produce various high-value industrial products,and can produce terpineol.The terpineol produced by it is widely used in flavor and fragrance,medicine,pesticide,printing industry,etc,and has good application prospects.Studying catalysts with high catalytic performance is of great significance for the deep processing of turpentine.There are many catalysts for preparing terpineol from turpentine,but ionic liquid catalysts show good catalytic performance,excellent recovery and reuse,and ionic liquid catalysts conform to the concept of green chemistry.The selectivity of the products after the reaction is higher than other catalysts.So in this thesis,an ionic liquid catalyst synthesized by a two-step synthesis method catalyzes the synthesis of terpineol from turpentine by esterification-saponification.The specific experiment content is as follows:(1)This article uses a two-step synthesis method to prepare different ionic liquid catalysts.The prepared ionic liquids are used to catalyze turpentine to prepare terpineol.The conversion rate of ?-pinene(X)and the selectivity of terpineol As an indicator,it is concluded that when the catalyst is bis-(3-methyl-1-imidazole)butylene dihydrogen sulfate,the conversion of turpentine oil to terpineol is the best,and the conversion rate of ?-pinene(X)is 93.67% and the selectivity of terpineol reaches 45.93%,and the catalyst is used to investigate the process conditions for the preparation of terpineol catalyzed by turpentine.(2)The effects of esterification agent,temperature,enoic acid ratio,catalyst dosage,reaction time and other factors on the reaction process of turpentine to terpineol were investigated through single factor experiments.After selecting acetic acid as the esterification agent,single factor investigation The reaction conditions are:6.8g turpentine,25 g acetic acid(the ratio of enoic acid is 1: 3)and the amount of catalyst 8%(wt%),the temperature of the esterification process is 80?,the mechanical stirring speed is 300 r / min,the reaction time is 8h;the saponification process The temperature is 80?,magnetic stirring for 1h,and the alkali-alcohol ratio is 20%.The final catalytic result is: the conversion rate(X)of ?-pinene is 99.03%,and the selectivity of terpineol is 78.15%.(3)Based on the single factor design experiment,the response surface method was used to optimize the process conditions.The optimized process conditions were: 6.8g turpentine,25 g acetic acid(acrylic acid ratio is 1: 3)and the amount of catalyst 8%(wt%),esterification process temperature 90?,mechanical stirring speed 300 r / min,reaction time 8h;saponification process temperature 80?,magnetic stirring 1h,alkali-alcohol ratio 20%,under this condition,?-pinene's The conversion rate(X)is100%,and the selectivity of terpineol is 85.91%.The reaction has good reproducibility and can be used 5 times.The selectivity of terpineol can still reach more than 60%,which is higher than other research options.(4)The prepared catalyst was characterized by infrared absorption spectroscopy and nuclear magnetic resonance.The characterization results were as expected.The reaction mechanism was preliminary discussed: the reaction-separation coupling mechanism is composed of the characteristics of ionic liquids and can be carried out in a two-phase system.Turpentine The ?-pinene in the compound undergoes a ring-opening reaction and combines with an acid to produce terpineol acetate,and then undergoes a saponification reaction to produce terpineol;in addition,the catalyst is deactivated because the chemical structure and ions of the organic products in the system after multiple uses There is a similar possibility for the structure of the liquid catalyst.When it is used repeatedly,there are some catalysts and products that are not completely separated.Some other substances that may be incorporated into the ionic liquid catalyst.When used several times,the purity of the ionic liquid catalyst is not as good as the initial use.The concentration gradually decreases,so the catalytic effect is not good.