Research And Optimization Of Synthesis Process Of Fosetyl-aluminum

Fosetyl-aluminum is an organic phosphorus fungicide with high efficiency and effective for many kinds of microorganisms or diseases.It can bidirectionally transmit up and down in plants,and it also has therapeutic and protective effects on plants.Fosetyl-aluminum has strong internal absorption and permeability.Otherwise,it has long-lasting effect,low toxicity and security.It has good market value.In this paper,the synthesis process of fosetyl-aluminum was studied by ammonium salt two-step method.Firstly,the synthesis of diethyl phosphite was studied.Diethyl phosphite is an important chemical product and an important intermediate for the synthesis of organophosphorus pesticides.It can be combined with other substances to form a composite flame retardant.Diethyl phosphite is widely used in organic synthesis.In the synthesis method of diethyl phosphite,the solventless method is a more economical route,and the synthesis process of diethyl phosphite has been a research hotspot in recent years.In this paper,the effects of phosphorus trichloride and ethanol molar ratio,reaction temperature and ethanol concentration on the content of diethyl phosphite were investigated by using phosphorus trichloride and ethanol as raw materials.By single factor study,the optimal reaction conditions for the synthesis process are: T=5-10?,the mole ration of phosphorus trichloride and ethanol is 1:3.2,97.5% ethanol,the content of diethyl phosphate can reach 79.8%.Secondly,the effects of reaction temperature and raw material dosage on the yield of fosetyl-aluminum were investigated by using pure diethyl phosphite,ammonia and aluminum sulfate as raw materials.The optimal conditions for the synthesis of fosetyl-aluminum were: the hydrolysis temperature is 35?,the holding temperature is 70?,the mole ration of diethyl phosphite and ammonia water is 1:1.15,the amount of aluminum sulfate is 1.05 times of the theoretical value,and the ammonia concentration is 25%,the yield of fosetyl-aluminum is87.8%.However,in industrial production,it is not feasible to synthesize fosetyl-aluminum by producing diethyl phosphite with a purity of more than 99%,which is inconvenient and uneconomical.Therefore,based on the single factor study,the continuous process of fosetyl-aluminum was studied by designing orthogonal experiments with three factors and three levels.The optimal conditions for the continuous synthesis process were the mole ration of phosphorus trichloride and ethanol is 1:3.3,ethanol content is 97.5%,the mole ration of trichlorination phosphorus and ammonia water is 1:0.8,and the yield of crude fosetyl-aluminum produced under the conditions is 91.4%,and the purity is 90.9%.The purity of the crude product after washing twice can reach 98% or more.During the experiment,the quantitative analysis of fosetyl-aluminum was carried out by ion chromatography,and carried out methodological validation,including linear relationship,precision and spike recovery.The standard curve fitting degree is0.999,and can be used to analyze data with good precision.Finally,according to the results of the pilot test,a preliminary plan for the industrialized production of the product was given,the process flow of some sections was briefly described,and the annual consumption of raw materials was calculated according to the requirement of annual output of 1000 tons,provide reference for follow-up process design.