Study On The Synthesis,Purification And Kinetics Of The Important Intermediate Of Prothioconazole

Due to its broad-spectrum,low toxicity,discrete,long residual effect and good conductivity,and both protective and therapeutic effect characteristics,three triazole fungicide,one of the hot research and development of pesticide,is very liked by the market.As a new type of broad-spectrum triazole fungicide developed by Bayer company in Germany,prothioconazole has good internal absorption,long effective period,and wide bactericidal spectrum compared with the traditional triazole drugs.The introduction of the structure of thio-ketone in the chemical constitution gives the unique charm of life for it.In addition to the control efficiency of all kinds of wheat diseases,the disease control efficacy of rape,peanut and other crops is also pro minent.At present,with market prices of its gradually stabilized,in order to improve the yield and to satisfied the extensive use of it in the prevention and cure of many diseases such as cereal crops and legume crops,We should develop a new process for the production of prothioconazole.Meanwhile,we should improve the utilization value of agricultural and sideline products.An important intermediate of prothioconazole has become the biggest obstacle of its production.The main ideas in the paper is to carry out a lot of research and study for the synthesis process of the important intermediate — 1-(1-chlorocyclopropyl)-2-(1,2,4-triazol-1-yl)ethan-1-one,so as to pave the way for the synthesis and production of prothioconazole.With the aim of the improvement of the yield of prothioconazole,the shortening of the production process and the decrease of energy consumption,we have studied the synthesis of 1-(1-chlorocyclopropyl)-2-(1,2,4-triazol-1-yl)ethan-1-one in the paper,and the main contents are as follows:1.On the basis of the second route — Back Grignard method,the synthetic routes of prothioconazole has been redesigned in the paper.The experimental group designed that 2-chloro-1-(1-chlorocyclopropyl)ethan-1-one and 1,2,4-triazole taken as the starting materials and prothioconazole was prepared by 3 steps in all.2.The new method of synthesis and purification of 1-(1-chlorocyclopropyl)-2-(1,2,4-triazol-1-yl)ethan-1-one were studied,and single factor experiments and orthogonal experiments were used to deter mine the optimum process conditions and optimize the process in the article.The best purification method was deter mined after the analysis of the crude products of 1-(1-chlorocyclopropyl)-2-(1,2,4-triazol-1-yl)ethan-1-one.There are four main factors affecting the yield were deter mined in the synthetic process of 1-(1-chlorocyclopropyl)-2-(1,2,4-triazol-1-yl)ethan-1-one.Analysis of single factor experiments and the orthogonal experiment indicates the optimum combination of reaction conditions.Under these conditions,a yield of 98.4% could be achieved.Through the analysis of range and variance,the order of the influential degree of each factor was deter mined as the dosage of acid binding agent,reaction temperature,feed ratio and reaction time.In purification process,the appropriate of strong acid,salt for ming solvent and salt dissociated solvent were selected,and the three main factors affecting the purified yield were deter mined,including the temperature of salt formation,the cooling temperature after salt formation and the amount of concentrated nitric acid.On the premise of ensuring the high purity and and less loss of crude product,Analysis of single factor experiments indicates the optimum combination of purification conditions.The ultimate yield of the product after purified was 95.95%,with a purity of 99%.The experimental process has practical significance for shortening the process flow or reducing the consumption quota.3.This paper discussed the kinetics of the synthesis reaction of 1-(1-chlorocyclopropyl)-2-(1,2,4-triazol-1-yl)ethan-1-one,and established the kinetic model.According to experimental datas,the reaction is deter mined as two order reaction.The reaction kinetics equation is (?).The preexponential factor of the reaction rate constant is k0= 3.67 × 107 L·mol-1·h-1 and the activation energy is Ea= 46.63 kJ/mol.The obtained kinetic equation is verified by experiment.4.The accurate and reliable chemical analysis method was studied,which can be used to detect the quality of the experiment.Solving the problem of chemical analysis in the course of study and the qualitative and quantitative analysis of the experimental products was carried out by gas chromatography.The product was analyzed and characterized by Fourier transform infrared spectroscopy,gas chromatography mass spectrometry and NMR spectrometer.Meanwhile,the obtained spectra were analyzed.The spectral data show that the compounds is the same as the expected target structure,and the product is 1-(1-chlorocyclopropyl)-2-(1,2,4-triazol-1-yl)ethan-1-one.