Study On Synthesis And Reaction Kinetics Of Diphenyl Phosphorazidate By Phase Transfer Catalysis

Diphenyl phosphorazidate is a colorless nonexplosive oil and is an important organic phosphor reagent.Because of its high reaction activity,it's been widely used in organic synthesis and medical synthesis.The technology at present(for the most of solvent method) of synthesis of DPPA is characterized by poor quality,compelx post treatment process,high cost etc.So the research of simple process,mild reaction conditions,simple post treatment process,high product purity and low cost becomes necessary.The studies to the establishment of product qualitative and quantitative analysis method,the selection of phase transfer catalyst,the technological conditions optimization and apparent kinetics etc.have a great scientific and applied significance for phase transfer catalysis synthesis of DPPA using diphenyl phosphoryl chloride(DPCP) as raw material.The analysis method of phase transfer catalysis reaction system using DPCP and sodium azide as raw material was rarely reported.So a reliable method of analyzing the content of DPPA is most significant to the whole process.The experimental conditions were on a C₁₈(150 mm×4.6 mm i.d),V(methanol): V(water)=70:30 as the mobile phase,and ultraviolet detector(determination at 254 nm) was used.The effects of catalysts,stirring speed and feeding way on the synthesis process was investigated,and was determined tetraethyl ammonium bromide as a better phase transfer catalyst,1700 r/min as a more proper stirring speed,and on the basis, orthogonal experimental method was employed.The optimized process conditions are as follows:reaction temperature was 35℃,reaction time was 13h,the molar ratio of sodium azide to DPCP was 1.9:1,the mass fraction of catalyst in reactant was 4.4wt%, and under the optimized technological conditions four times repeat experiments showed the yields of DPPA were above 88%,and the contents were above 96%.The apparent kinetics of synthesis for preparing DPPA from fined DPCP in the presence of phase transfer catalyst tetraethyl ammonium bromide was investigated and obtained:the reaction order of the synthesis was n=1,and the apparent activation energy was Ea=5.086 KJ/mol,pre-exponential factor was A=1.256 h^-1.By the obtained kinetics equation,the maximal relative deviation of conversion rate of DPCP at any reaction time between calculated and experimental values at 35℃was less than 10%,which indicates the kinetics equations can be suitable to applied to guide the synthesis process of DPPA.