The Study of Synthesis and Characterization of Dibutylmagnesium
|School||Wuhan Institute of Technology|
|Keywords||Dibutylmagnesium Grignard reagent Butyl lithium 2-chlorobutane orthogonal experimental|
Dibutylmagnesium (DBM) is an important organic metal compounds,whose chemical reactivity is better than Grignard reagent. Dibutylmagnesiumwas widely used in organic synthesis and as a raw material to prepare olefinpolymerization catalyst. Numerous attempts have been made to prepareDibutylmagnesium, such as magnesium powder deoxygenize alkyl mercury,Grignard reagents under the effect of dioxane to preparate dibutylmagnesium,etc. However, they were all accompanied by one or more problems such thatcomplex preparation steps were indispensible、diffcult post-processing wasresulted、expensive raw materials were required. Therefore, it was urgent todevelop a new synthetic route. In our research, the DBM, which has twodifferent ends, i.e. n-butyl and isobutyl, was prepared by a two-step synthesismethod according to the principle of synthesis of organometallic compounds,and the synthesis parameters was optimized. The specific work was asfollows:Firstly, the influences of reaction conditions, such as temperature, time,and ratio between different reactants on the synthesis of Grignard reagent werestudied by orthogonal experimental method. A97%of Grignard reagent wasobtained when the reaction temperature is35℃, the reaction timeis4h, theratio of magnesium powder to2-chlorobutane is1︰1.2and the ratio of etherto2-chlorobutane is7︰1.Secondly, The conditions of preparation of dibutylmagnesium withGrignard reagent and butyl lithium were optimized, the results showed thatwhen the reaction temperature is0℃, reaction timeis0.5h and the ratio ofGrignard reagent to n-butyllithium is1︰1, the yield of dibutylmagnesium was99%. The process will be outstanding for the industrial application because ofits good characteristics such as short reaction time, high yield, and stablequality.Thirdly, electrometric titration was used to determine the concentration of inorganic chlorine and total chlorine from dibutylmagnesium products, theresults showed it was very accurate and precise to use electrometric titrationmethod which could be used in the producing process and for product qualitycontrol.Fourthly, the structure of dibutylmagnesium product was disclosed by gaschromatography, nuclear magnetic resonance spectrum.Fifth, the performance evaluation of quality of dibutylmagnesium showedthat: the performance was as good as products abroad, and could meetindustrial application requirements.