Studies On Synthetical Technology Of P-nitrobenzyl Bromide

Bromine is the primary material in chemical industry.With the production of bromine going up,bromic chemical industry develop rapidly.At present,the government is energetically developing medicine industry to change the status of that most synthetic drugs depended on importation.It is predicted that series medicine of bromine would be the key research program,p-Nitrobenzyl bromide is a normal intermediate,applied in synthesis of new antirheumatic,cephalosporin antibiotic and medicals for septic shock.In this thesis,the synthesis and separation of p-nitrobenzyl bromide are researched scientifically.This study not only answer the call come from the government,but also is available in increasing benefits and improving competitiveness of the plants on the market.p-Nitrobenzyl bromide is prepared from p-nitrotolune via free-radical substitution in carbon tetrachloride with N-bromosuccinamide as brominating agent and benzoyl peroxide as initiator.The influences of the molar ratio of raw materials, reaction time,reaction temperature,initiator and initiator quality on the yield of the product are discussed by the advance expeiments,the orthogonal experiments and the single-factor optimized experiments.The experimental result shows that the optimum conditions are as follows:the molar ratio of p-nitrotolune,N-bromosuccinamide is 1.2:1,reaction time is 1.5h,reaction temperature is 80℃,and initiator is benzoyl peroxide.The yield of the product can be up to 90.17%under the optimum condition. Products are characterized by melting point,IR and NMR.The results fit closely with references,and the feasibility of the method using in this study is proved.In this paper,solubilities of p-nitrotolune and p-nitrobenzyl bromide in carbon tetrachloride,acetone,acetic acid,tolune,ethyl acetate and ethanol at normal pressure are determined systemically,using dynamic method with computer online laser-monitoring observation technique.The soluility curves are protracted and the heat of dissolution about every system are predicted.Results indicate that ethanol is the optimum solvent for recrystallization in the separation of p-nitrobenzyl bromide, and acetone,acetic acid,ethyl acetate would be available in the application of p-nitrobenzyl bromide.Solubility data of systems determined are correlated by the two parameters equation,the three parameters equation and theλh equation, respectively.The heat of dissolution and excess enthalpy of all systems are estimated by the model equations.The average relative error between the value calculated by those models and the experimental value of 133 data points are 2.80%,2.13%and 2.53%respectively.