Preliminary Study On New Green Technology Of Methyl Ester Natural Products

Ester compounds was extracted from natural products.Because of its special application value,which can be used as the main ingredient of drugs and artificial fragrances and fragrances.So it is widely used in perfumes,cosmetics,pharmaceuticals and food industries and many other fields.Liquid acid is a commonly used catalyst in the conventional preparation of methyl esters,and mechanically stirred tanks and fixed bed reactors are commonly used reactors,in the actual industrial quantitative production process.However,problems Such as long reaction time,low mass transfer and heat transfer efficiency,high energy consumption,and strong corrosiveness to the equipment,environmental pollution,etc.These are contrary to the development of a sustainable environment.In this paper,salicylic acid and octanoic acid are used as the reaction raw materials,and cation exchange resin is used as the catalyst to prepare corresponding methyl ester compounds.The effect of the reaction on the reaction was investigated by the type of catalyst,the circulation flow of the reaction raw material,the amount of the catalyst in the total mass,the molar ratio of the reaction material,the reaction temperature,and the repeated use of the catalyst.A designed improvement of Micro Intensified Fixed Bed-Reactor(MIFR)was also adopted as a new type of high efficiency multiphase reactor.Because of its unique advantages of good mass transfer heat transfer efficiency,high conversion efficiency,simple design structure,low energy consumption,etc.In this paper,we mainly studied the synthesis of two kinds of lipids,investigated the process conditions,and enhanced the reaction.By calculating the thermodynamics and kinetics of the reaction and regression of the experimental data.In this paper,two kinds of methyl ester reactions were studied and micro-reinforced by the reactor designed by the research group.Which were optimized the process conditions and calculated the thermodynamic and kinetic parameters.All these provide the basis for the later exploration of MIFR in the design,optimization,and industrial amplification of the reaction process.The research progress made on this topic is as follows:1.Methyl Salicylate and reaction intensificationSalicylic acid and methanol were used as starting materials to prepare methyl salicylate,and finally the optimized process conditions were obtained:The catalyst was selected as NKC-9,the material ratio of salicylic acid to methanol was 1:6;the amount of catalyst was 20%of the total mass(w/w);reaction temperature was 348.15K;circulation flow was 1.5L/h and experimental results show that NKC-9 still has good reusability.In order to correct the non-ideality of the solution,the UNIFAC group contribution method was used,and the reaction equilibrium constants in the temperature range of 328.15?348.15 K were obtained.The relationship between the thermodynamic equilibrium constants of methyl salicylate and temperature is as follows:The reaction enthalpy(?rH0)and entropy(?rS0)were-5.59 kJ mol-1 and 3.25 J mol-1K-1,respectively,When in the operating temperature range.Kinetic study of the reaction of salicylic acid with methanol catalyzed by NKC-9 resin in MIFR were derived by using kinetic model based on Eley-Rideal(E-R)mechanism,under experimental conditions the reaction rate equation can be written as:The calculated value of this model is almost consistent with the experimental value of this study,indicating that E-R can be used to describe the esterification of salicylic acid with methanol.2.N-caprylic acid esterification and reaction intensificationSimilar to the above reaction,and the previous condition was explored,the anhydrous NKC-9 catalyst was directly selected.Finally,the optimum technological conditions for the reaction of octanoic acid with methanol to prepare methyl octanoate were as follows:the material ratio of N-caprylic acid to methanol was 1:6;the amount of catalyst was 20%of the total mass(w/w);reaction temperature was 318.15K;circulation flow was 1.2L/h and experimental results show that NKC-9 still has good reusability.In order to correct the non-ideality of the solution,the UNIFAC group contribution method was used,and the reaction equilibrium constants in the temperature range of 303.15?318.15 K were obtained.The relationship between the thermodynamic equilibrium constants of methyl salicylate and temperature is as follows:The reaction enthalpy(?rH0)and entropy(?rS0)were-5.69 kJ·mol-1 and 6.75 J·mol-1·K-1,When in the operating temperature range.NKC-9 also catalyzes the reaction of octanoic acid with methanol in MIFR,kinetic studies were derived using the kinetic model of the Eley-Rideal(E-R)mechanism,under experimental conditions the reaction rate equation can be written as:The calculated value of this model is almost consistent with the experimental value of this study,indicating that E-R can be used to describe the N-caprylic acid esterification.